Note: Descriptions are shown in the official language in which they were submitted.
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WIRELESS NETWORK SYNCHRONIZATION
OF CELLS AND CLIENT DEVICES ON A NETWORK
INVENTORS: DAVID L. BROWN AND FRED S. HIRT
CROSS-REFERENCE TO RELATED APPLICATIONS
[00011 The present application claims priority, under 35 U.S.C. 119, of U.S.
Provisional Patent Application No. 60/760,362, filed January 6, 2006 and
entitled "Securing
Transactions Between an Electric Key and Lock Within Proximity of Each Other,"
and U.S.
Patent Application No. 11/620,603, filed January 5, 2007 and entitled
"Integrated Power
Management of a Client Device via System Time Slot Assignment;" U.S. Patent
Application
No. 11/620,600, filed January 5, 2007 and entitled "Dynamic Cell Size
Variation Via
Wireless Link Parameter Adjustment;" U.S. Patent Application No. 11/620,577,
filed January
5, 2007 and entitled "Dynamic Real-Time Tiered Client Access;" and U.S. Patent
Application
No. 11/620,581 filed January 5, 2007 and entitled "Wireless Network
Synchronization of
Cells and Client Devices on a Network," the entireties of which are hereby
incorporated by
reference.
BACKGROUND
[00021 Optimizing sales transactions, providing secure access to physical and
digital
assets, uniquely identifying individuals, and generally improving
communications and data
exchange are challenges faced by many businesses and organizations. Ensuring
that these
processes are safe, efficient, reliable, and simple is important to companies,
merchants,
service providers, users, and consumers. Well-known technologies such as user-
specific
magnetic cards (e.g., credit and debit cards, employee badges), and more
recent developments
such as contactless cards designed to allow access or authorization when
placed near a
compatible reader, are examples of attempts to address the need to instill
efficiency and
integrity in, for example, the general classes of transactions described
above.
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SUMMARY
[0003] According to at least one aspect of one or more embodiments of the
present
invention, a system includes: a first wireless device having a first range of
wireless coverage;
a second wireless device having a second range of wireless coverage; and a
synchronization
S device having a third range of wireless coverage and configured for
communication with the
first wireless device and the second wireless device, where an operation of
the first fixed
wireless device and an operation of the second fixed wireless device are
coordinated based on
synchronization information wirelessly broadcast by the synchronization
device.
[0004] According to at least one other aspect of one or more embodiments of
the
present invention, a gaming system includes: an electronic gaming machine; and
a first
wireless device operatively coupled to the electronic gaming machine and
arranged to
wirelessly detect a presence of a portable wireless user device in proximity
to the electronic
gaming machine.
[0005] According to at least one other aspect of one or more embodiments of
the
present invention, an apparatus includes a physical, portable key device,
where the key device
has: a wireless transceiver adapted to wirelessly receive synchronization
information from a
network device, and processing circuitry adapted to communicate data with a
fixed-proximity
sensing reader device in accordance with the synchronization information.
[0006] According to at least one other aspect of one or more embodiments of
the
present invention, an apparatus includes a predetermined reader device, where
the reader
device has: a wireless transceiver adapted to wirelessly detect presence of a
portable wireless
client device, and processing circuitry adapted to communicate data with the
client device in
accordance with synchronization information received from a network device.
100071 According to at least one other aspect of one or more embodiments of
the
present invention, an apparatus includes a predetermined network device, where
the network
device has: a wireless transmitter configured to broadcast synchronization
information in a
wireless coverage area of the network device to coordinate a data exchange
between a first
wireless device and a second wireless device located in the wireless coverage
area.
[0008] According to at least one other aspect of one or more embodiments of
the
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present invention, an apparatus includes: a first wireless transceiver
configured to wirelessly
receive synchronization data from a network device; and a second wireless
transceiver
configured to communicate data with a portable wireless client device in
accordance with the
synchronization data.
[00091 According to at least one other aspect of one or more embodiments of
the
present invention, a method for facilitating data exchange includes: using a
first wireless
transceiver to wirelessly receive synchronization information from a network
device; and
using a second wireless transceiver to wirelessly communicate data with a
proximity detected
portable wireless client device in accordance with the synchronization
information.
[00101 The features and advantages described herein are not all inclusive,
and, in
particular, many additional features and advantages will be apparent to those
skilled in the art
in view of the following description. Moreover, it should be noted that lhe
language used
herein has been principally selected for readability and instructional
purposes and may not
have been selected to circumscribe the present invention.
BRIEF DESCRIPTION OF DRAWINGS.
[0011] Figure I shows a single wireless cell in which a reader decoder circuit
(RDC)
and a personal digital key (PDK) are present_
[0012] Figure 2 shows partially overlapping RDC cells.
[0013] Figure 3 shows synchronized partially overlapping RDC cells.
[0014] Figure 4 shows a synchronized multi-cell system in accordance with one
or more
embodiments of the present invention.
100151 Figure 5 shows a PDK in accordance with one or more einbodiments of the
present invention.
[0016] Figure 6 shows a portion of the PDK shown in Figure S.
[0017] Figure 7 shows a portion of the PDK shown in Figure 5.
[00181 Figure 8 shows an RDC in accordance with one or more embodiments of the
present invention.
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[0019] Figure 9 shows an RDC in accordance with one or more embodiments of the
present invention.
[0020] Figure 10 shows an arrangement of a timeslot in accordance with one or
more
embodiments of the present invention.
[0021] Figure 11 shows a superframe in accordance with one or more embodiments
of
the present invention.
[0022] Figure 12 shows a coordinator superfranne in accordance with one or
more
embodiments of the present invention.
[0023] Figure 13 shows an overall framing structure in accordance with one or
more
embodiments of the present invention.
[0024] Figure 14 shows an RDC beacon for use in a single cell system in
accordance
with one or more embodiments of the present invention.
[0025] Figure 15 shows a single cell system in accordance with one or more
embodiments of the present invention.
[0026] Figure 16 shows a PDK-RDC handshake in accordance with one or more
embodiments of the present invention.
[0027] FigLire 17 shows a coordinator beacon configuration in accordance with
one or
more embodiments of the present invention.
[0028] Figure 18 shows a PDK transmit timeslot enable operation in accordance
with
one or more embodiments of the present invention.
[0029] Figure 19 shows a location tracking system configuration in accordance
with one
or more embodiments of the present invention.
[0030] Figure 20 shows a coordinator RDC (CRDC) location tracking handshake in
accordance with one or more embodiments of the present invention.
[0031] Figure 21 shows a configuration in which RDCs and PDKs are coordinated
within a CRDC cell in accordance with one or more embodiments of the present
invention.
[00321 Figure 22 shows a CRDC framing and PDK timeslot response operation in
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accordance with one or more embodiments of the present invention.
[0033] Figure 23 shows a CRDC beacon and PDK response handshake in accordance
with one or more embodiments of the present invention.
[0034] Figure 24 shows a PDK/RDC association in a CRDC cell in accordance with
one or more embodiments of the present invention.
[0035] Figure 25 shows an RDC beacon transmission in accordance with one or
more
embodiments of the present invention.
[0036] Figure 26 shows a deep sleep state diagram in accordance with one or
more
embodiments of the present invention.
[0037] Figure 27 shows an authorization denial handshake operation in
accordance with
one or more embodiments of the present invention.
[0038] Figure 28 shows an authorization grant and association handshake in
accordance
with one or more embodiments of the present invention.
[0039] Figure 29 shows a single cell with multiple PDK access in accordance
with one
or more embodiments of the present invention.
100401 Figure 30 shows multiple*single cell RDCs with cell overlap in
accordance with
one or more embodiments of the present invention.
[0041] Figure 31 shows a floor layout and cell distribution in accordance with
one or
more embodiments of the present invention.
[0042] Figure 32 shows a gambling table with RDCs in accordance with one or
more
embodiments of the present invention.
[0043] Figure 33 shows a CRDC beacon to central server flow in accordance with
one
or more embodiments of the present invention.
[0044] Figure 34 shows a CRDC beacon to central server handshake in accordance
with
one or more embodiments of the present invention.
[0045] Figure 35 shows a configuration of overlapping CRDC cells in accordance
with
one or more embodiments of the present invention.
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[0046] Figure 36 shows a c-beacon handoff for RDC-PDK communication in
accordance with one or more embodiments of the present invention.
[0047] Figure 37 shows a PDK wakeup and response state flow in accordance with
one
or more embodiments of the present invention.
[0048] Figure 38 shows a configuration of an electronic game with an
iintegrated RDC
in accordance with one or more embodiments of the present invention.
[0049] Figure 39 shows an electronic game player tracking and game enable
handshake
in accordance with one or more embodiments of the present invention.
[0050] Figure 40 shows an electronic game player association handshake in
accordance
with one or more embodiments of the present invention.
[0051] Figure 41 shows a configuration of an electronic game with an
integrated RDC
in accordance with one or more embodiments of the present invention.
[0052] Figure 42 shows an electronic game player tracking and game enable
handshake
in accordance with one or more embodiments of the present invention.
[0053] Figure 43 shows an electronic game player association handshake in
accordance
with one or more embodiments of the present invention.
[0054] Each of the figures referenced above depict an embodiment of the
present
invention for purposes of illustration only. Those skill.ed in the art will
readily recognize
from the following description that one or more other embodiments of the
structures,
methods, and systems illustrated herein may be used without departing from the
principles of
the present invention.
DETAILED DESCRIPTION
[0055] In the following description of embodiments of the present invention,
numerous
specific details are set forth in order to provide a more thorough
understanding of the present
invention. However, it will be apparent to one skilled in the art that the
present invention
may be practiced without one or more of these specific details. In other
instances, well-
known features have not been described in detail to avoid unnecessarily
complicating the
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description.
[0056] In general, embodiments of the present. invention relate to a technique
for
synchronizing (or "coordinating") multiple wireless cells, in any one of which
an individual
(or "user") can reliably and securely conduct one or more wireless
transactions with some
device in one or more of the cells. Particularly, in one or more embodiments,
wireless cells
are synchronized in order to prevent wireless collisions and extend the
battery life of
individual user units.
[0057] At perhaps a most basic level, one or more embodiments includes a
personal
digital key ("PDK") and a reader decoder circuit ("RDC"). In general, a PDK is
a portable
wireless device that may be conveniently carried by an individual to
facilitate wireless
tracking and/or allow the individual to wirelessly access various
applications, assets, and/or
services. As further described in detail below with reference to Figures 5 -
7, a PDK may be
any device that (i) may be worn, placed in a pocket, wallet, or purse of a
user, or attached to
equipment, (ii) has a bi-directional wireless communications transceiver, and
(iii) stores
public and/or secret electronic identification numbers, as possibly some set
of cryptographic
keys. The form factor of the PDK is not limiting, so long as the PDK may be
portably, and
preferably conveniently and seamlessly, carried by an individual. For example,
a PDK may
be in the form of a "key fob" or a card, or in certain embodiments, a PDF may
actually be
integrated with or implemented in another device, such as a watch or mobile
computing
device (e.g., cellular phone, personal digital assistant (PDA)).
[00581 An RDC, as used in one or more embodiments, is a device that can
wirelessly
interact with a PDK to link the PDK user with various applications, assets,
and/or services.
The RDC may be a fixed access point serving as a gatekeeper for a PDK
requesting access to
a particular system. An RDC may be used in various settings and/or
applications. For
example, an RDC may be physically incorporated into a casino floor itself, an
electronic
game, a doorway, a pedestrian traffic monitoring point, a personal computer
application, an e-
commerce device (e.g., an automatic teller machine (ATM)), or any other
application
requiring a secure transaction or access control.
[0059] Further, secure data exchange for various financial and/or retail
applications may
be facilitated through use of a PDK and RDC in accordance with one or more
embodiments.
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For example, a purchasing system may be implemented whereby a consumer can
purchase
goods or services using his/her personal "key" (e.g., a PDK) based on the key
being in
detectable wireless proximity of a reader device (e.g., an RDC). The purchase
transaction
may then be carried out based on some data exchange between the key and the
reader device,
where the key stores accessible, and possibly encrypted or encoded,
information about the
consumer (e.g., name,- address, phone number, bank account information,
biometric
information, credit or debit card information). The validation or
authentication of the
consumer may occur either on the key itself and/or by the reader device. In
the case of "on-
key" validation, for example, the reader device may pass some information
about the
consumer (e.g., a biometric input, such as fingerprint data) to the key, which
then matches the
data provided by the reader device with permanently stored secure data about
the consumer.
j00601 Various other applications or uses involving any number of PDK and RDC
devices are possible in accordance with one or more embodiments. Accordingly,
while
examples of scenarios and applications are described herein for purposes of
illustration and
clarity, the present invention is not limited to any particular application,
scenario, setting, or
use.
Sinzle Cell Operation of the RDC and PDK
[0061] Now referring to Figure 1, it shows a single cell 10 in which, at some
point in
time, an RDC 12 and a PDK 14 are present. The RDC 12 may be some fixed device
that has
a cell radius defined by its wireless coverage boundary. When an individual
carrying the
PDK 14 comes into proximity of the RDC 12 by entering a coverage area of the
RDC 12, a
wireless communications session is initiated between the PDK 14 and the RDC
12. If the
RDC 12 determines that the PDK 14 is authorized to communicate, information
between the
PDK 14 and the RDC 12 may be securely exchanged..Information securely obtained
from the
user's PDK 14 may then be. used locally or sent through a back-end
communications channel
to a central server (not shown). When the transaction completes or when the
PDK 141eaves
the coverage area of the RDC 12, wireless communication between the RDC 12 and
the PDK
14 ceases. Thereafter, the RDC 12 may remain idle (i.e., be in a"tracking"
mode) until a
PDK again enters the cell 10.
Unsynchronized Multi-Cell Operation o Multiple RDCs and PDKs
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[00621 Now referring to Figure 2, in certain implementations, multiple RDC
cells 20,
22, 24 may exist in an area. The RDCs in the multiple cells 20, 22, 24 may or
may not be
aware of each other, but are able to interact with one or'more PDKs. The PDKs,
in turn, are
capable of interacting with the RDCs. As shown in Figure 2, there are three
partially
overlapping RDC cells 20, 22, 24. An RDC 26, 28, 30 in cells 20, 22, 24,
respectively, is
independent and may not be in association with the other RDCs. Although the
cells 20, 22,
24 partially overlap, each RDC 26, 28, 30 is capable of wirelessly
communicating with any
PDK 29, 31 within its cell boundary.
[0063] In one or more embodiments, the RDC 26, 28, 30 is capable of
determining if
energy is present on any given wireless channel. The RDC 26, 28, 30 may then
determine the
best channel to operate on and continue to place an identification marker (or
"beacon") out
for any PDK 29, 31 that enters its cell boundary.
[0064) The PDK 29, 31 itself may be responsible for locating an RDC 26, 28, 30
by
searching through available wireless channels, communicating with an RDC 26,
28, 30, and
notifying the. RDC 26, 28, 30 of its presence. In an implementation where two
RDCs can
communicate with one another (e.g., RDCs 26, 28 in cells 20, 22 shown in
Figure 2), the
RDCs may select different comrnunication frequencies. However, in the case
where cells
overlap, but each RDC cannot directly communicate with one another (e.g., RDCs
28, 30 in
cells 22, 24 shown in Figure 2), any PDK intending to access an RDC, may have
to alert the
RDC of possible collisions on the wireless channel on which the RDC is
operating.
Synchronized Multi-Cell Operation of 11Multiple RDCs and PDKs
[0065] In certain implementations, multiple RDCs may be placed to allow an
overlap of
cells between each adjacent RDC within a confined area. This permits each RDC
to be aware
of its surrounding RDCs, thereby allowing synchronization of each RDC to the
other. For
example, now referring to Figure 3, there are shown three partially
overlapping RDC cells 40,
42, 44 with RDCs 46, 48, 50. The cell 40, 42, 44 of each respective RDC 46,
48, 50 overlaps
the cell of the adjacent RDC 46, 48, 50. In such a manner, each RDC 46, 48, 50
may initiate
wireless communication with an adjacent RDC 46, 48, 50. This begins a
negotiation process
among the RDCs 46, 48, 50 to determine which RDC 46,.48, 50 should be the
coordinator
and on what channel to communicate.
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[0066] Although any of the RDCs 46, 48, 50 may be the coordinator, in the
example
shown in Figure 3, RDC 48 in cell 42 may be a favorable candidate. Its
selection permits
ubiquitous coverage of the RDCs 46, 48, 50 shown iri 'Figure 3, additionally
providing
multiple transactions and timing alignment through a "daisy chain" whereby RDC
46
synchronizes RDC 48 and RDC 48 synchronizes RDC 50.
[0067] Still referring to Figure 3, each RDC 46, 48, 50 may also share
frequency and
timeslot information among each other and with one or more PDKs. It is noted
that if a PDK
is located at an edge of, for example, cell 40, that PDK. may still monitor
the other channels
that adjacent RDCs 48, 50 are operating on, but may not have access to these
RDCs. Thus, in
a configuration such as that shown in Figure 3, a PDK may be forced to consume
more energy
due to the monitoring of multiple channels. Further, it is noted that as cell
density increases,
more collisions may begin occurring and/or active communication times may
increase.
Coordinated Multi-Cell O,peratiQn
[0068] Now referring to Figure 4, it shows an exemplar synchronized (or
"coordinated") multi-cell system 60 in accordance with one or more
embodiments. As will
be apparent from the description below, a synchronized multi-cell system may
provide
ubiquitous PDK and RDC synchronization as well as PDK battery conservation
within the
system 60. Further, in addition to ubiquitous synchronization, channel and
frequency
capacity may both be coordinated, thereby reducing collisions while increasing
system
throughput.
[0069] Turning now to Figure 4 particularly, a coordinator RDC ("CRDC") 62 has
ubiquitous coverage of a plurality of cells 64, 66, 68 in the system 60. , In
one or more
embodiments, the CRDC 62 provides beacon transmissions, which can be tised to
synchronize a plurality of devices within the coverage area 76 of the CRDC 62.
In other
2S words, by providing wide-area coverage, a plurality of devices, both RDCs
70, 72, 74 and
PDKs (shown, but not labeled in Figure 4), in the coverage area 76 are able to
monitor a
wireless transmission beacon broadcast by the CRDC 62 and determine how and
when to
communicate in a coordinated manner. Further, in one or more embodiments, the
CRDC 62
may broadcast additional information including, but not limited to, a beacon
transmission
rate, framing information, channel information, system identification, and/or
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identification. Moreover, it is noted that although the CRDC 62 may provide
timing and
certain system related information, RDCs 70, 72, 74 and PDKs may still
communicate among
themselves.
[0070] As described above with reference to Figures 1- 4, there are at least
three
different types of devices (or software entities) that may be used, for
example, in a
synchronized multi-cell system, such as that shown in Figure 4. A PDK is a
trackable device
having secure electronic keys and that may be portably carried by a user. An
RDC is a device
that acts as a gatekeeper controlling access of a PDK to a particular system.
A CRDC is a
device that is used to synchronize one or more RDCs and PDKs within a
particular
lo geographic area formed of either a single cell or multiple cells. A more
detailed description
of each of these components is now provided below.
PDK
[0071] Now referring to Figure 5, it shows an example PDK 80 in accordance
with one
or more embodiments. Based on a specific application or use of the PDK 80, the
PDK 80
may have different configurations for interacting with the PDK user. For
example, the PDK
80 may have no user input mechanism or display, may have a single button input
mechanism,
may have a multi-button input mechanism, may have a biometric input mechanism,
and/or
may have an interactive user input mechanism and/or display.
[00721 As shown in Figure 5, the PDK 80 has a wireless radio frequency (RF)
media
access control (MAC) and physical layer device 82 that facilitates bi-
directional
communications with external wireless RF devices, such as an RDC (not shown).
In one or
more embodiments, the wireless RF MAC and physical layer device 82 may
communicate
according to an IEEE 802.15_4 protocol. However, in one or more other
embodiments, the
PDK 80 may be capable of communicating according to one or more different
wireless
protocols.
[0073I The PDK 80 also has a service and applicatiom layer controller 84 that
includes a
MAC portion 94 that serves as an interface with the wireless RF MAC and
physical layer
device 82. Further, the service and application layer controller 84 also
includes portions that
provide specific functions used to protect electronic keys and services of the
PDK 80. Further
still, the service and application layer controller 84 may support an optional
user interface 86,
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which if implemented, allows user interaction with the PDK 80. A cryptography
engine 88
may also be resident on the PDK 80.
[0074] Now also referring to Figure 6, it shows a non-volatile memory storage
90 and a
volatile memory storage 92 of the PDK 80. These two devices 90, 92 are related
to security
storage. In one or more embodiments, these devices 90, 92 may be accessible by
an RDC
(not shown) having the appropriate security algorithms and by private service
providers
having the correct security information. However, in one or more other
embodiments, certain
secured data may not be wirelessly communicated at all, in which case,
validation or
authorization occurs on the PDK 80 itself.
[0075] Specifically as to the non-volatile memory storage 90, a public serial
number
may be used to identify the PDK 80 and allow secure look-up of a secure serial
number and a
cryptography key via a remote server (not shown). The secure serial number may
be thought
of as being equivalent to, for example, encoded user identification
information stored in a
magnetic strip of a credit card, whereby such information is not visible to
the outside world.
The cryptography key may be used to allow decoding of the secure serial number
from, for
example, an RDC (not shown).
[0075I Further, it is noted that in one or more embodiments, the non-volatile
memory
storage 90 and associated parameter lengths may be dynamically assigned, with
overall
constraints depending on, for example, available memory in the PDK 80.
[0077] Now, specifically as to the volatile memory storage 92, this area may
be used for
security and may allow a service provider to store a profile containing secret
keys and other
secure information, such as privilege information. A service provider
identification value
may be stored to allow the service provider to easily identify the user. In
addition, a service
provider service identification value may be stored and used to allow that
service provider to
access that information. The PDK 80 validates that service provider
identification value via
the service provider secret key before allowing access to that service
provider's profile area in
the PDK 80. Further, as shown in Figure 6, the volatile memory storage 92 may
have a
number of service provider profiles.
[0078] Now also referring to Figure 7, the service provider profile area may
be of a
variable length and allow a service provider the flexibility to store various
parameters. The
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length may be determined by a byte count following the service provider's
secret key in the
memory area as shown in Figure 7.
RDC
[0079] Next, turning to a more detailed description of an RDC 100 according to
one or
more embodiments, reference is made below to Figures 8 and 9. In general, an
RDC 100, as
described above, may be fixed and used to allow a PDK access into a particular
system (e.g.,
gaming/casino system, financial institution, retail system). The RDC 100 may
have different
configurations to support different types of secure transactions. Some
examples of
applications and uses of RDCs include, but are not limited to, casino slot
machines and
gaming consoles, secure entryway control, user/equipment location tracking,
personal
computers and components thereof (e.g., disk drives), financial institution
interactions, and
retail purchasing. In the case of a personal computer, or any computer system
for that matter,
a reader device, such as an RDC, may be used to control access to certain data
stored in the
computer system. Thus, in such embodiments, an RDC 100 may be thought of as
providing a
form of digital content management.
[0080] In certain cases, the RDC 100 effectively acts as a gatekeeper allowing
authorized individuals access to specific information or transactions. In
other cases, because
an RDC 100 may use proximity detection for determining if a PDK is within a
particular
geographical area, the RDC 100 may also be used for tracking one or more PDKs
within a
given area or network. In still other cases, an RDC 100 may be used for both
location
tracking and secure transaction purposes.
[0081] Figure 8 shows a type of RDC 100 that uses a single wireless RF MAC and
physical layer device 102. In RDC 100, communications are passed through the
single
wireless RF MAC and physical layer device 102. The single wireless RF MAC and
physical
layer device 102 facilitates bi-directional communication with one or more
external RF
wireless devices, such as a PDK (not shown). Thus, the single wireless RF MAC
and
physical layer device 102 may communicate with both PDKs according to assigned
time slots
(further described below) and one or more CRDCs (described in further detail
below).
Further, it is noted that in one or more embodiments, the single wireless RF
MAC and
physical layer device 102 may wirelessly communicate according to an IEEE
802.15.4
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protocol. However, in one or more other embodiments, the RDC 100 may be
capable of
communicating according to one or more different wireless protocols.
[0082] The RDC 100 also has a service and application layer controller 104.
The
service and application layer controller 104 has a MAC portion 106 specific to
a wireless
protocol of the RDC 100. The service and application layer controller 104 may
further
provide functions related to associating and tracking PDKs (not shown), as
well as providing
information back to a service provider.
[00831 The service and application layer controller 104 includes system
parameters and
configuration information 108 that may be used to identify the RDC 100 and
define how the
RDC 100 operates within a given environment. Further, the system parameters
and
configuration information 108 may define how the RF link is time slotted
and/or how RF
frequencies are used in the system. In one or more embodinients, these values
may be
optimized to reduce power consumption within one or more PDKs (not shown).
[00841 Still referring to the RDC 100 shown in Figure 8, a cryptography engine
110
may also be present. One or more of various storage elements may also exist in
the service
and application layer controller 104. A secure key storage area 112 may be
programmed to
define public, secret, and/or cryptography keys for the RDC 100.
[00851 Further, in one or- more embodiments, the service and application layer
controller 104 may have additional memory areas, one or more of which may
dynamically
change dependent on system changes and wireless PDK connections. A volatile
service
provider storage 114 may allow a service provider to store semi-static
information related to a
specific PDK (not shown) or group of PDKs (not shown) for real-time access for
those
devices. An example might relate to a hotel room door lock. With a hotel room
door, service
provider information related to a PDK may be stored in the RDC: When a user
comes within
proximity of the door, the door could unlock. Thus, in this example, the RDC
is not required
to interface with a back-end server in real-time, thereby reducing bandwidth
consumption to
the back-end server, while allowing the user immediate access. Moreover, in
one or more
embodiments, the RDC may have a connection to a network or other
infrastructure for
receiving control signals as to which PDKs should be allowed to unlock the
door.
100861 The service and application layer controller 104 may also have a
proximity
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tracking PDK list 116 that includes PDK identity information, signal quality
metrics, and/or
time stamps for each PDK (not shown) that is in proximity of the RDC 100. Such
information may be used in the RDC 100 to perform an operation and/or may be
relayed to a
back-end server when, for example, location tracking is desired.
- S [0087] Still referring to Figure 8, the service and application layer
controller 104 may
also have an associated PDK parameter storage 118. The associated PDK
parameter storage
118 may contain a list of one or more PDKs (not shown) actively performing
transactions
with the RDC 100. It is noted that in one or more embodiments, although such
transactions
are performed with the RDC 100, the actual processing result of the RDC 100
to/from PDK
transaction may be passed to a back-end server for further processing.
[0088] A service provider interface 120 may allow both control and query of
the RDC
100. The service provider interface 120 may further provide the transport for
keys from a
PDK (not shown). In one or more embodiments, the service provider interface
120 may use a
universal asynchronous transmitter receiver (UART) interface and may allow
some level of
control and status of the RDC 100.
[0089] An externai service provider controller 122 may be attached to the
service
provider interface 120 with a system stack 124 residing in the external
service provider
controller 122. The system stack 124 may allow a third party to easily
interface with the RDC
100, possibly requiring function calls to the system stack 124. Further, the
external service
provider controller 122 may provide translation of data. It is still further
noted that the
external service provider controller 122 and the RDC 100 may reside on the
same physical
component (e.g., circuit board).
[0090] Now referring to Figure 9, it shows another type of RDC 130, which has
an
additional wireless RF MAC and physical layer device 13Z. In this
configuration,
components having like reference numbers as those reference numbers in Figure
8 function
identically or similarly to the corresponding components in Figure.8. The
additional wireless
RF MAC and physical layer device 132 may be used to maintain synchronization
with a
CRDC (not shown) and pass networking related information, while the other
wireless RF
MAC and physical layer device 102 may be used to communicate with one or more
PDKs
(not shown) within a cell of the RDC 130. Further, the service and application
layer
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controller 104 may have an additional MAC portion 134 to interface with the
additional
wireless RF MAC and physical layer device 132.
[0091] Still referring to the RDC 130, the use of dual wireless transceivers
102, 132
may allow for increased throughput and efficient use of the RF spectrum
available to the
-system. Thus, in other words, these multiple wireless links allow
simultaneous reception of
data from client devices (e.g., PDKs) and of CRDC timing information on
separate channels,
thereby eliminating the need for back-channel synchronization of the network.
Further, the
multiple wireless links may allow for the simultaneous proximity sensing of
multiple client
devices (e.g., PDKs) in a "tracking" mode, along with the association of a
client device with
one particular cell for wireless application (e.g., secure transaction)
purposes. For example,
an RDC serving as a wireless player tracking device on a casino floor may,
while keeping
track of multiple transient players entering and leaving the zone of coverage
of that particular
tracking device, invite a particular player to begin a gaming session. This
session may also
include the exchange of player information with, for example, both the game
and its back-end
server to allow credit for games played and money spent. In another scenario;
the system may
facilitate another entire suite of applications, such as, for example,
unlocking a hotel room
door, while simultaneously keeping track of unrelated client devices coming
and going within
its coverage range.
CRDC
[0092I Next, turning to a more detailed description of a CRDC according to one
or
more embodiments, a CRDC may, for example, be an RDC of either of the types
described
above with reference to Figures 8 and 9. At least one difference, however,
between a CRDC
and an RDC is that the CRDC has increased RF power output, or more generally,
casts a
broader range of wireless coverage. Another difference is that, in one or more
embodiments,
a CRDC may not communicate bi-directionally with a PDK, whereas an RDC of the
types
described above with reference to Figures 8 and 9 may. Moreover, a CRDC may be
capable
of communicating with another CRDC, and may also be capable of communicating
with an
RDC. It is noted that CRDC-CRDC communication may allow for frame
synchronization
and frequency planning without requiring a wired connection between the CRDCs.
The same
may be true for CRDC-RDC communications. In certain implernentations, it may
occur that
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CRDC cell boundaries do not overlap, and thus, the corresponding CRDCs may not
be able to
directly communicate with another. In this case, an RDC that is between the
cells may
communicate with both CRDCs and act as a communication bridge to pass
frequency and
other control information in an effort to coordinate the system.
[0093] Still describing the general application and use of a CRDC in -
accordance with
one or more embodiments, the CRDC may serve as a stand-alone wireless beacon
that may be
used to coordinate the timing and activities of individual, physically
separated wireless
providers (e.g., RDCs) with defined coverage areas, along with their clients
(e.g., PDKs) in an
autonomous, wireless proximity sensing and data transfer network. A CRDC may
also be
used to propagate -system-wide information (e.g., periodic changes in
cryptographic keys),
thereby relieving traffic otherwise loading a wired back-end network linking
individual cells
to the back-end system. Thus, the CRDC may act as a system-wide master clock
across
multiple cells that may not be close enough to synchronize with each other
directly without a
wired connection.
Wireless Protocol
[0094] As described above, a system in accordance with one or more embodiments
may
rely, or at least partly be based, on an IEEE 802.15.4 protocol. In relation
to a protocol usable
in one or more embodiments, a"timeslot" is defined as a period of time that
information is
communicated between two devices. Figure 10 shows an example of portions of a
timeslot in
accordance with one or more embodiments. The timeslot is divided into a frame
(or physical
packet data unit (PPDU)) and inter-frame spacing (IFS). The frame includes
synchronization
information and carries the payload of data. The IFS allows time for a
receiving end unit to
process the data in the frame and transmitter turn-around time. Both the PPDU
and the IFS
may be variable in length as determined by an amount of data carried in the
frame.
[00951 The frame is broken down into a sync header (SHR), a physical header
(PHR),
and a physical service data unit (PSDU). The SHR may contain a preamble
sequence and
start-of-frame delimiter (SFD) that allows a receiving device to acquire the
RF signal and
synchronize to the frame. The PSDU may then be used to carry both 802.15.4 MAC
and user
data information. Further, it is noted that the PSDU may be of a variable
length that is
determined by the type of MAC and data information being carried.
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100961 Still referring to Figure 10, the frame may be further divided into
symbols,
which, in turn, are divided into bits. In one or more embodiments, each symbol
may includes
4 bits that are sent least significant bit to most significant bit at the base
band level.
[00971 Now refeming to Figure 11, a "superframe" is formed of multiple
timeslots. The
superframe may be used in a beacon-enabled synchronous network where PDKs can
find an
RDC and/or CRDC fixed device. The superframe may allow a PDK to efficiently
determine
if an RDC is present on any given frequency.
[0098] The superframe may be configured such that timeslot 0(TSo) is the
"beacon
timeslot." Each superframe that is transmitted may start with a beacon
timeslot. Further,
each timeslot may be equally spaced so that a PDK and RDC can communicate.
[00991 Further, it is noted that in one or more embodiments, a superframe may
be of a
variable length dependent on the resolution to a timeslot. The initial number
of timeslots
within a superframe may be, for example, 16; but, in one or more other
embodiments, a
superframe may have a different number of timeslots.
[00100] Now referring to Figure 12, a "coordinator superframe" (c-superframe)
may be
formed of multiple superframes. In one or more embodiments, a c-superframe may
be
generated by a CRDC. A c-superframe may provide one or more advantages over a
superframe. For example, a c-superframe may provide better battery management
for a PDK,
as well as provide distributed superfrarne and timeslots in a high density
networking
environment.
[00101] As shown in Figure 12, a c-superframe may have multiple superframes.
Because
each superframe may have a beacon, as described above with reference to Figure
11, multiple
beacons may be transmitted per c-superframe. This may allow a PDK to quickly
determine if
it is within a system. A c-superframe may also number the superframes, so -
that both an RDC
and a PDK can realize their position within the framing structure.
[00102] Figure 13 shows an overall framing structure of a timeslot as
described above
with reference to Figure 10, a superframe as described above with reference to
Figure 11, and
a c-superframe as described above with reference to Figure 12.
Beacons
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[00103] As discussed above with reference to Figure 11, a beacon may be sent
in every
superframe. The beacon is used to alert PDKs (and RDCs when a CRDC is present)
of
system information and timing of the framing structure employed. In one or
more
embodiments, such a configuration may be implemented using an IEEE 802.15.4
protocol.
However, in one or more other embodiments, communication may occur according
to one or
more different wireless protocols.
[00104] In a single cell configuration in which one RDC is present (shown, for
example,
in Figure 1), the beacon may be transmitted in timeslot 0 of a superframe
boundary. By
transmitting the beacon periodically, a PDK may wake up and find the beacon
within a short
period of time and realize that it is within some particular network.
[00105] In an unsynchronized multi-cell configuration in which multiple RDCs
are
geographically located near each other, but no synchronization between RDCs is
implemented (shown, for example, in Figure 2), a PDK may still wake up, detect
the presence
of the RDCs, and synchronize and communicate with each RDC due to the presence
of the
beacon on each RDC.
[001061 In a high density area in which multiple RDCs are present, a CRDC may
most
likely be present. In such a configuration, the CRDC may transmit the beacon,
and all RDCs
and PDKs in the coverage area of the CRDC align to the CRDC beacon. The CRDC
may
send a beacon on each superframe, as well as a c-superframe and other
configuration
information to the RDCs and PDKs.
[00107] Now referring to Figure 14, in a single cell configuration (shown, for
example,
in Figure 1), a beacon is periodically output based on a specific number of
timeslots. Further,
in one or more embodiments, the beacon may be used in accordance an IEEE
802.15.4
protocol, with additional data attached indicating it is an RDC. At the end of
each
superframe, there may exist an additional idle period that allows tolerance in
an over-the-air
protocol.
[00108] After a beacon is transmitted, a PDK may immediately respond provided
it
follows the rules of what is know in the art as "carrier sense multiple access
- collision
avoidance" (CSMA-CA). If a PDK finds that the channel is busy in the current
timeslot, the
PDK may back-off and attempt again to access the RDC in another timeslot
following the
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same rules. In the case the PDK is not able to communicate with the RDC, the
PDK may
wait for the next beacon and attempt again.
[00109] Figure 15 shows a single cell configuration in accordance with one or
more
embodiments. As shown in Figure 15, a single fixed RDC 140 may be connected to
a back-
end server (not shown). The single cell system shown in Figure 15 includes,
for example: a
computing controller with an operating system, an application, a back-end
server interface,
and a system stack; the RDC 140, which is the gateway for a PDK and performs
authorization
(the system stack and RDC 140 together allow a user who has a PDK to access
the
application dependent on authorization from the back-end server); and a PDK
142 that
includes necessary security information and is within reasonable proximity to
wirelessly
communicate with the RDC 140.
[00110] An example handshake of the PDK 142 with the RDC 140 is shown in
Figure
16. The RDC 140 outputs a periodic beacon based on timeslot 0 of a superframe.
Eventually, a user walks within the coverage area of the RDC 140, and the
user's PDK 142
detects the beacon from the RDC 140. The PDK 142 determines if it is
registered to this
RDC 140 (or network), and, if so, responds with a PDK location response. The
RDC 140
then detects the PDK location response and performs a link request to the PDK
142. The
PDK 142 then accepts the request by replying with a link grant, and the two
devices 140, 142
are now in data exchange mode. In data exchange mode, the two devices 140, 142
may
transfer specific security information that result in the RDC 140 enabling
access to the system
through the system stack, computing controller, andlor back-end central
server.
[00111] Periodically, data may be exchanged between the RDC 140 and the PDK
142 to
ensure that the PDK 142 is still within close proximity of the RDC 140. As
long as data
exchange continues on a periodic basis, the application may remain enabled and
the user can
continue to access the application.
[00112] After some amount of time, the user walks away from the RDC 140
causing the
data exchange to cease, in which case, the system stack indicates to the
computing controller
that the PDK 142 is out of range. The computing controller then disables the
application to
prevent unauthorized access. Regardless of data exchange, the RDC 140 may
continue to
transmit periodic beacons to guarantee that other PDKs may gain access to the
application.
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[00113] Now referring to Figure 17, a configuration of a "coordinator beacon"
(c-
beacon) is shown. The coordinator beacon may be generated by a CRDC, or RDC
behaving
like a CRDC. As described above, a CRDC may cover a large geographic area
covering a
plurality of RDCs and PDKs within that area. The c-beacon may be a standard
beacon sent in
the first timeslot of each superframe as shown in Figure 17.
[00114] A c-beacon, in accoTdance with one or more embodiments, may have
properties
that are different than those associated with an IEEE 802.15.4 standard
beacon. For example,
the standard c-beacon carries a field indicating the beacon is a c-beacon.
Further, a c-beacon,
in normal operation, is a unidirectional transmission from a CRDC. Further
still, a c-beacon
may contain other c-beacon related information: number of slots in a
superframe; number of
superframes in a c-superframe; the channels on which adjacent CRDCs operate;
current
superframe number; current c-superframe number; site ID; CRDC ID; PDK
superframe mask;
and PDK timeslot mask.
[001151 Further, it is noted that while beacons may be transmitted from a CRDC
on
timeslot 0 of each superframe, remaining timeslots of a superframe may be left
open for
unsynchronized communications between PDKs and RDCs. The term "unsynchronized"
is
used to describe communications between the PDKs and the RDCs because the RDC
and
PDK share a common CRDC beacon, but the PDK may not get synchronized directly
to an
RDC beacon. In this manner, the PDK and RDC may appear to represent a peer-to-
peer
network.
[00116] C-beacon information described above relates to configuration fields
that allow
the system to operate efficiently when using a CRDC. In the case of, for
example, a large
scale system, a service provider of the system may have knowledge of RDC
coverage relative
to the CRDC. The following description provides details of these fields.
[001171 A "superframe len" field may be governed by an IEEE 802.15.4 protocol.
The
number of slots may be from, for example, 21 to 214. The number of slots in a
superframe
may be used to define the repetition rate for the beacon.
[00118] A"c-superframelen" field may be used to define a higher layer counter
used for
extended power savings in a PDK. The c-superframe len value may also define
the number
of beacons within a superframe. If the superframe is configured to not have a
beacon, then
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this field may be ignored.
Name Type Valid Range Description
C- Integer 0 to 15 Defines the number of Superframes in
Superframe Len a C-Superframe. Number of
Superframes is defined as
2C-Superframe_Len
[001191 A "CRDC chan flags" field may be used to indicate to a PDK what
channels
are used by adjacent CRDCs.
Name Type Bit Description
CRDC Chan Flags Binary When any bit in this field is set to a
1, an adjacent CRDC is transmitting
on that frequency.
Binary 0 1 = Channel 0 available
0= Channel 0 not available
Binary 1 1 = Channel 1 available
0= Channel 1 not available
Binary 2 1 = Channel 2 available
0= Channel 2 not available
Binary 3 1 = Channel 3 available
0 = Channel 3 not available
Binary 4 1 = Channel 4 available
0= Channel 4 not available
Binary 5 1= Channel 5 available
0= Channel 5 not available
Binary 6 1 = Channel 6 available
0= Channel 6 not available
Binary 7 1 = Channel 7 available
0= Channel 7 not available
Binary 8 1= Channel 8 available
0= Channel 8 not available
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Binary 9 1 Channel 9 available
0 = Channel 9 not available
Binary 10 1= Channel 10 available
0 = Channel 10 not available
Binary 11 1= Channel 11 available
0 = Channel 11 not available
Binary 12 1 = Channel 12 available
0= Channel 12 not available
Binary 13 1 = Channel 13 available.
0= Channel 13 not available
Binary 14 1= Channel 14 available
0= Channel 14 not available
Binary 15 1 = Channel 15 available
0= Channel 15 not available
[00120] A"superframe cnt" field may be used to define a current superframe (or
beacon) count within a c-superframe. If the superframe is configured to 'not
have a beacon,
then this field may not be transmitted.
Name Type Valid Range Description
Superframe Cnt Integer 0 to 65535 Defines the current Superframe count.
[001211 A"c-superframecnt" field may be used to define a current c-superframe
count.
If the superframe is configured to not have a beacon, then this field may not
be transmitted.
Name Type Valid Range Description
C- Integer 0 to 65535 Defines the current C-Superframe
Superframe Cnt count.
[00122I A "PDK sf ts msk" field may be used to define the bits of a superframe
count
and the timeslot count to use for PDK superframe and timeslot sequencing while
in a tracking
mode. If the superframe is configured to not have a beacon, then this field
may not be
transmitted.
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Name Type Valid Range Description
PDO SF TS Msk Defines which bits are to be used
for determining PDK superframes
and timeslots to communicate with
an RDC during location tracking.
Superframe Mask Binary 0000000000000 Defines the Superframe mask
to I = enable bit
1111111111111 0=maskbit
Timeslot Mask Binary 000 to 111 Defines the Timeslot mask
1 = enable bit
0 = mask bit
[001231 The PDK sf ts msk value may be used in conjunction with a portion of
the
service provider unique PDK identification value and may be used to determine
the exact
superframe and timeslot the PDK is permitted to transmit a location identifier
back to the
RDCs. The necessary logic and variables required to perform this operation are
illustrated in
s Figure 18_
[00124] Further, in one or more embodiments, to set the mask value of a
particular PDK,
a "set_pdkmsk val" function may be used. The mask may be used over the
superframe and
timeslot counts and service provider's PDK ID to determine the superframe and
timeslot the
PDK is active on in the framing structure. In other words, the set_pdk_msk_val
function may
be used to set a mask for the PDK in an effort to establish at what times the
PDK can
communicate with an RDC. The function may return a pass or fail indication to
indicate
whether the mask has been successfully set. Conversely, to obtain the mask
value being used
by a particular PDK, a "get_pdk rnsk val" function may be used to retrieve the
current PDK
superframe and timeslot mask parameters.
[001251 Using, for example, the masking approach described above, individual
client
devices (e.g., PDKs) within a given cell (e.g., an RDC's wireless coverage
area) may be
addressed via real-time re-provisioning on command. Thus, in other words, by
reserving time
slots for both client device transmission and reception (based on masks
established by the
network), client transmission and reception time slots may be efficiently
coordinated to
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reduce collision likelihood and allow for tiered client access, assignment of
specific classes,
and/or targeting an individual user for preferential, non-contended system
access. Further, in
one or more embodiments, bit masks may be changed to iinclude or exclude
specific users (or
classes of users). Still further, in one or more embodiments, bit masks may be
changed to
dynamically alter access to the network by users or. classes of users as
traffic load on the
network changes. Moreover, it is noted that once a specific client exits the
network,
previously reserved time slots of that client may be reassigned to one or more
other client
devices in the network.
[00126] To provide an example, there may be multiple client devices (e.g.,
PDKs) in
proximity of a particular fixed reader device (e.g., an RDC). Each of these
client devices,
other than providing a location response, may request some data exchange with
the reader
device in order carry out a secure transaction. In an effort to reduce
collision and coordinate
the time slots that each client device "talks" with the reader device, a mask
may be
communicated to each client device to set the times at which the client device
is to
communicate with the reader device. Further, certain ones of the client
devices may be
afforded some level of priority, in which case the masks would be set
accordingly. For
example, masks may be set according to a class of a user of a PDK or to a
class of the PDK
itself. To facilitate such differentiation, priority level or tier level data
may be present in an
RDC or CRDC to be used when setting a mask for a particular client device or
group thereof.
Thus, in such a manner, there is provided a technique for dynamic real-time
tiered client
access. Moreover, it is noted that in one or more embodiments, a CSMA-CA
mechanism
may be implemented as a backup approach to facilitate data exchange.
[00127] Further, in one or more embodiments, utilization of a tiered access
system to
transfer and receive data to/from a specific user or client device anywhere
within a wireless
network may allow for simultaneously operating network-wide two-way
communications
without altering the network. Thus, in other words, although one or more
embodiments relate
to an autonomous wireless proximity sensing and data transfer network, such a
network may
be used to notify, page, or transfer data possibly unrelated to one or more of
the applications
which a majority of the client devices on the network are using (or typically
use) (such
applications being for the purposes of, for example, tracking, access control,
and/or digital
rights management). In another example, a network device may be able to
associate a PDK
CA 02636167 2008-07-03
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ID to a particular user and then provide messaging capability based on the
identity of the user.
Thus, in this ca'se, one or more embodiments may be combined with tiering to
provide
multiple messaging levels for different users.
[00128] The ability to assign tiers to the network may also enable low latency
responses
from targeted client devices. Accordingly, by integrating features into the
client device that
may take advantage of a two-way network capability, a system in accordance
with one or
more embodiments may allow for the simultaneous communication and control of
external
devices via real-time client command along with a general purpose low data
rate two-way
network.
[00129] Continuing with the description of c-beacon information in accordance
with one
or more embodiments, a"site ID" field may carry a value that each CRDC
transmits to all
PDKs and RDCs within a coverage area of the CRDC. The site ID value allows a
PDK to
determine if it can access the current site or if it needs to request
permissions to access the
site's network.
Name Type Valid Range Description
Site ID Integer 0 to 65535 Defines the current sites ID.
[00130] A "CRDCID" field may carry a value that each CRDC transmits to all
PDKs
and RDCs within a coverage area of the CRDC. The CRDC ID may be used, for
example,
for geographical reference.
Name Type Valid Range Description
CRDC ID Integer 0 to 65535 Defines the current CRDC ID.
[00131] Now turning to a description of a use of a c-beacon, reference is made
to Figures
19 and 20. A location tracking example in accordance =with one or more
embodiments is
shown in Figure 19. There are various different types of devices in the system
150 shown in
Figure 19. First, there is a CRDC 152 that may provide system information and
facilitate
synchronization for RDCs and PDKs. The system 150 also has RDCs 154, 156,
which listen
for PDKs and report the status of each PDK found within its respective cell
158, 160. The
system 150 further includes a PDK 162 that is mobile and capable of being
moving around.
Further, the system 150 has a server 164, which is the back-end computer that
controls the
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CRDC 152, acquires information from the RDCs 154, 156, and may provide a
graphical
representation to monitoring personnel via a computer monitor (not shown).
[001321 Accordingly, Figure 19 shows how location tracking of a PDK is
possible and a
handshake between different parts of the system 150. A handshake example of
PDK location
tracking in a CRDC configuration. is shown in Figure 20. The CRDC 152.
periodically
broadcasts a beacon in timeslot 0 of each superframe. Enabled client devices
within the
CRDC cell boundary receive the beacon. After the PDK 162 receives the beacon
and
determines that the beacon is from a system that it is registered to, the PDK
162 broadcasts a
PDK location response that is received by the RDCs 154, 156. Both RDC 154 and
RDC 156
receive the response, log the PDK ID, the signal quality metrics, and
timestamps the
information. The packet of information may then be sent to the server 164,
where the server
164 processes the data from each RDC 154, 156 and performs a location
estimation that may
then be presented to an operator. At the beginning of the next superframe, the
beacon is again
transmitted and the process is repeated until the PDK 162 can no longer be
heard due to it
being out of range.
[00133] Now referring to Figure 21, it shows a system 170 in which both PDKs
and
RDCs are coordinated within a CRDC cell boundary. Because, in one or more
embodiments,
RDCs are stationary devices and may occasionally be relocated, the RDCs may be
initially
coordinated by manually configuring both timeslots and frequencies they
operate on.
[00134] As shown in Figure 21, one CRDC cell 172 and 6 smaller RDC cells 174,
176,
178, 180, 182, 184 exist. The CRDC cell 172 provides ubiquitous coverage to
the RDC cells
174, 176, 178, 180, 182, 184. Each RDC cell 174, 176, 178, 180, 182, 184
overlaps its
adjacent RDCs in a manner resulting in a high rate of collisions if the RDCs
186, 188, 190,
192, 194, 196 attempt to communicate with a PDK 198 on the same channel. It is
envisioned
that all the RDCs 186, 188, 190, 192, 194, 196 could be on different
frequencies, but then the
PDK 198 would be required to access each frequency for some duration,
resulting in reduced
battery life. To eliminate interference between the RDCs 186, 188, 190, 192,
194, 196 and
provide the PDK 198 with an efficient means to conduct secure transactions,
the system 170
shown in Figure 21 may be used.
[00135] To optimize the system 170 for battery conservation of the PDK 198,
each RDC
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186, 188, 190, 192, 194, 196 may be provided with a dual RF physical
interface. 'The primary
interface is for monitoring a c-beacon and the PDK 198 located in close
proximity, and to
signal the PDK 198 to switch to another channel for further communications
with that
particular RDC. In this case, the CRDC (not shown) may transmit c-beacons,
whereby all
RDCs and PDKs will gain timing synchronization.
[00136] Based on the configuration shown in Figure 21, the c-beacon fields
described
above may be configured as follows: superframe len = 4 (24 = 16 timeslots); c-
superframe len = 4(2a = 16 superframes); CRDC chan flags = b0000000000000010
(most
significant bit to least significant bit - CRDC channels); PDK sf ts msk =
b000000000011111 (mask all but 2 least significant bits of the superframe
count and don't
mask any timeslot bits); site ID = 0x1234 (arbitrary site identification); and
CRDC ID =
Ox0001 (arbitrary CRDC ID).
[001371 Another piece of information that may be inherent to the PDK is a
unique
service provider PDK ID. The unique service provider PDK ID is located in the
PDK and
may be compared with the superframe and timeslot count prior to applying the
mask, but may
not affect the superframe and timeslot counts from a time reference
standpoint. In this case,
the unique service providers PDK ID for this PDK may be equal to 0x0003.
[001381 Using the above described values for the c-beacon, the following
system
attributes result (the superframe is 16 timeslots long, so once out of every
16 timeslots, a c-
beacon is created allowing the PDK to determine if a system with the correct
system ID
exists): the c-superframe length is set to 16; the CRDC chan flags indicate to
the PDK the
number of CRDC channels available in the system; the PDIC sf ts msk indicates
which bits
to logically AND with the superframe and timeslot count to determine which
slots to respond
on (in this case, the PDK sf ts msk is a hex value of Ox001F that is ANDed
with the
superframe and timeslot count resulting in one response timeslot); and the
site ID and CRDC
ID are arbitrary values and may be left to the service provider for selecting
unique
identification values.
[00139] Using the above described exemplar system configuration information
and
having a PDK with a unique service provider ID of 0x0003, Figure 22 shows how
the PDK
may operate in a CRDC framing structure. As shown in Figure 22, the c-
superframe len is
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set to 16 - thus, the superframe count counts from 0 to 15 and then starts
over at 0. Each
superframe then includes 16 timeslots of which the first timeslot is timeslot
0 and includes the
beacon. The superframe len is also set to 16 - thus, there are 16 timeslots
for each
superframe. Again, the timeslots are numbered from 0 to 15, and restart at 0
for each
superframe.
[00140] In one or more embodiments, based on the parameters set by the system
and the
unique service provider PDK ID, the PDK may periodically transmit a PDK
location response
in timeslot 3 of each superframe on a modulo 4 basis. This causes the PDK to
respond in
timeslot 3 of superframes 0, 4, 8, and 12 of a c-superframe. It is noted that
the PDK may
1o follow the CSMA-CA standard and if the PDK cannot respond in its timeslot,
it may wait for
its next designated superframe and timeslot to respond.
[00141] If an RDC requests to begin communication with a PDK, the RDC may
immediately respond on the next even timeslot, which, in this case, is
timeslot 4. Any RDC,
may respond, but RDCs may have to use the CSMA-CA rule prior to responding to
the PDK
transmission. If an RDC begins communications with a PDK, the following
timeslot may be
used to instruct the PDK to go to another channel, where bi-directional
conununications may
cornmence.
[00142] Further, in one or more embodiments, an active superframe may occur
when
unmasked bits in the superframe count equal the corresponding unmasked bits in
the unique
20_ service providers PDK ID. In this case, the superframe mask is a value of
0x003 and the
unique service provider PDK ID is 0x0003.
[00143] With this information, the following calculation occurs:
b000000000000 superframe count[ 15:4]
xor b000000000000 unique Service Provider PDK ID[14:3]
b000000000000 result of xor function
and b000000000111 Superframe Mask[11:0]
b000000000000 result of AND function
nor all bits
1 result is true
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[00144] As shown above, a portion of the superframe count is exclusive-ORed
with a
portion of the unique service provider PDK ID. The result of the exclusive-OR
is all 0's.
Then, the superframe mask is ANDed with the result of the exclusive-OR
function. The
AND operation also results in all 0's. The result of the AND function is then
compared to
zero by NORing all of the bits together and results in a 1 or "-true" output,
indicating the bits
compared between the superframe count and the unique service provider PDK ID
are a match.
[00145] An active timeslot occurs when the unmasked bits in the 3 most
significant
positions of the timeslot count equal the unmasked bits in the unique service
provider PDK
ID's 3 least significant bits and the timeslot count least significant bit is
a 1(the PDK
transmits on odd frames). In this case, the timeslot mask is a value of 0x7
and the unique
service providers PDK ID's 3 least significant bits are Ox3.
[001461 With this information, the following calculation occiirs:
b0l 1 timeslot count[3 :1 ]
xor bOl l unique Service Provider PDK ID[2:0]
b000 result of xor function
and b 111 Timeslot Mask
b000 result of AND function
nor all bits
1 result is true
[00147] As shown above, the timeslot count is exclusive-ORed with a portion of
the
unique service provider PDK ID. The result of the exclusive-OR is al10's.
Then, the timeslot
mask is ANDed with the result of the exclusive-OR function. The AND operation
also
results in all 0's. The result of the AND function is then compared to zero by
NORing all of
the bits together and result in a 1 or "true" output, indicating the bits
compared.between the
timeslot count and the unique service provider PDK ID are a match.
[00148] The last portion of the calculation that needs to be completed (as
described
above) is to verify the last bit of the slot count is a'1,' indicating an odd
slot. If the
unmasked superframe and timeslot bits do not match the appropriate unique
service provider
PDK ID, the results will be "false" and no match will occur. In the examples
described
above, the superframe mask was set to unmask the 2 least significant bits of
the superframe
CA 02636167 2008-07-03
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count to show that it is possible to allow a PDK to come up more frequently
than the c-
superframe count. By increasing the superframe mask to 4 bits, this example
would allow the
PDK to respond once per c-superframe (because the c-superframe was set to 16)
and the
modulo for the mask would be 24, or 16.
[00149] The timeslot mask may be set to allow all timeslot bits to be
correlated to
determine the timeslot, allowing the PDK to respond once per superframe.
Further, it is noted
that it may be possible to mask some of the timeslot bits to increase the
number of times a
PDK can respond within a superframe.
[00150] In one or more embodiments, a PDK may periodically wake up to
determine
whether it is within a particular system. Upon a periodic wake up, the PDK
will detect a c-
beacon indicating that the particular system is present, along with system
information. The
PDK will collect the system information and determine the cun: ent'superframe
count of a c-
superframe. The PDK may also put parameters (e.g., PDK sf ts msk) in place to
start
immediate battery save in the system.
[00151] Based on an approximate time, the PDK may awake just prior to where it
believes the next superframe is that it should communicate on, and will listen
for the beacon
and begin responding with the PDK location response message.
.[00152] As shown in Figure 23, a CRDC may update its system information on
each
superframe and output a c-beacon with current information to all PDKs and
RDCs. The PDK
then waits for its predefined superframe and timeslot and responds. This
scenario continues
to occur until the PDK leaves the CRDC cell or an RDC responds to the PDK.
[001531 As described above, a CRDC may continue to output a c-beacon, and the
PDK
periodically awakes to re-align to the superframe and respond to the c-beacon.
If a RDC is
present and wants to communicate with the PDK, the RDC may respond on the even
timeslot
immediately available after the PDK's transmission. Figure 24 shows how the
communications handshake between the PDK and RDC may occur. Particularly,
Figure 24
depicts one CRDC, one RDC with two active channels (i.e., using two wireless
links), and a
PDK.
[00154] With continued reference to Figure 24, the CRDC outputs a c-beacon of
which
the RDC and PDK are aligned. The PDK realizes that the c-beacon's superframe
count
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correlates to its internal predefined active superframe count, and then waits
for the
appropriate timeslot to respond to the system with its PDK location response.
When the PDK
responds on the c-beacon channel, the RDC detects the response and determines
that it wants
to associate with the PDK. The RDC then creates a message including its own
RDC ID, the
PDK's ID, a command to switch to channel 2, and a predicted superframe and
timeslot the
PDK should respond on. The PDK, in response, switches to channel 2 and waits
for the
appropriate superframe and timeslot count and transmits a link request along
with its PDK ID
and the destination RDC ID. The destination RDC then receives the information
and
responds back to the PDK with a link grant. Communications may now begin
between the
two devices exchanging the appropriate information to maintain the PDK-RDC
link. To
maintain synchronization, the RDC may define the periodic communication
frequency with
the PDK and will periodically generate a request to the PDK to exchange
information. The
PDK may then reconfigure its wake parameters to that of the RDC, as the RDC is
maintaining
superframe synchronization.
[00155] It is noted that in one or more embodiments, such as that described
immediately
above, the RDC may have a dual physical interface, maintaining synchronization
with the
CRDC on channel 1, while associating with one or more PDKs on channel 2. The
physical
interface connected to channel 1 provides timing to the physical interface on
channel 2.
[001561 Further, because the RDC may have intelligence on both channels, the
RDC may
provide coordination of PDKs that it wants to redirect to channel 2 and PDKs
that are on
channel 2. More specifically, the RDC may move the superframe and timeslot
that a PDK
communicates to the RDC on; if another PDK with the same timeslot requirements
is present
on channel 1 and the RDC wants to associate with it.
CRDC Slot and Channel coordination
2s [001571 In one or more embodiments, a CRDC may be configured via a remote
connection to a server or automatically. Using remote configuration, the
server may have
knowledge of RDCs located within the CRDC cell boundary and may perform
optimum
channel and timeslot planning.
[001581 When the CRDC is configured automatically, the CRDC may scan all
channels
and find the channel with the least interference. The CRDC may then begin
transmitting a c-
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beacon.
[001591 All RDCs located within a CRDC cell boundary may place the CRDC into
its
local CRDC database =and complete scanning all other channels to determine if
other CRDCs
are present. In the case multiple CRDCs are found, the RDC may communicate to
each
CRDC its findings if possible.
[001601 Each CRDC may coordinate through that RDC to setup channels and
timeslots
to prevent interference between CRDCs. In one or more cases, the CRDC may
select another
channel and disregard the timeslot information because CRDCs may not be
required to be
timing coordinated. Further, it is noted that any RDC that detects more than
one CRDC may
select the CRDC with the best signal quality.
Protocol Operation
[001611 The following describes a protocol operation in a single cell
coordinated system
using a CRDC configuration. In one or more embodiments, there may be
additional protocol
fields required to allow interoperability between single cell and coordinated
multi-cell
configurations. Such additional protocol fields may provide information to
RDCs and PDKs
that are located in near proximity to each other, or within a CRDC cell.
[00162] A network format field may provide information to RDCs and PDKs
related to
the specific configuration the single cell or coordinated cells are operating
in.
Name Type Valid Range Description
Proxense NWK FMT Defines the network configuration
employed for an RDC or CRDC
Network Type Integer 0 to 7 Defines the network type employed.
0 = Single Cell
1 = Multi-Cell coordinated
2 = Multi-Cell coordinated w/
CRDC
3-7=RFU
Beacon Source Binary 0 or 1 Defines the source of the beacon.
O=RDC
I = CRDC
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Broadcast Flag Binary 0 or 1 Defines if this is a broadcast
message.
0 = not broadcast
1 = broadcast
Timeslot Select Integer 0 to 3 Defines how an RDC and PDK
utilize timeslots in a system.
0 = no timeslots assigned
1 = 802.15.4 Beacon enabled
2= PDK uses even timeslots /
RDC uses odd timeslots
3 = PDK uses odd timeslots /
RDC uses even timeslots
[00163] A network type value may be used to define a cell network
configuration. An
RDC receiving this field may determine its operating mode based on this field.
If an RDC
receives a network type of single cell from another transmitting RDC, the RDC
may tune to
another channel to avoid collisions with the other RDC. If the RDC-receives a
network type
of coordinated multi-cell, the RDC may join the multi-cell coordinated system.
If the RDC
receives a network type of coordinated multi-cell with CR.DC, the RDC may join
the CRDC
network if the site ID is the same.
[00164] The PDK may also receive this information and adjust its operating
mode to
comply with the system employed. If the PDK detects the system to be single
cell, the PDK
may conform to more of an IEEE 802.15.4 protocol, communicating with the RDC
in such a
manner. The PDK may be aware that it is required to communicate with a
specific RDC ID.
The PDK may still have the capability to periodically monitor other channels
for other RDCs
in the local vicinity.
[001651 If a PDK detects the system is multi-cell coordinated, the PDK may
receive
further information indicating the other RDC frequencies in use in the
coordinated network
and may adjust its system operating parameters appropriately.
[00166] If the PDK determines the system is multi-cell CRDC coordinated, the
PDK may
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adjust its operating parameters appropriately. The PDK may acknowledge that a
c-beacon is
present and may broadcast a PDK location response. The PDK may also understand
that an
RDC with a different ID other than a CRDC ID may attempt to communication with
the
PDK.
[00167] A "beacon source" field may indicate to all RDCs and PDKs in the
general
proximity of the type of beacon being generated. This information may be
helpful,
specifically when in a multi-cell CRDC system, and allows. RDCs to distinguish
between
RDC generated beacons and CRDC generated beacons.
[00168] A "broadcast flag" may indicate to all recipients that the information
being sent
is intentionally being broadcast to all devices that can receive particular
protocol information.
In some cases, a message that may be sent to a specific PDK may also be
broadcast to all
PDKs. This flag assists the PDKs in determining how to treat the information.
[001691 A timeslot select field may indicate to PDKs and RDCs how the
timeslots are
configured in the system. This field may further be used to determine if an
RDC and PDK are
to use even-based or odd-based timeslots for responding.
[00170I In order for an RDC or PDK to determine that a network is of a
particular type, a
network identifier may be used.
Name Type Valid Range Description
Proxense Network ASCII Proxense An 8 byte ASCII value identifying
Identifier the network to be a Proxense
network
Single Cell Standalone Operation
[00171] The following description is based on, for example, an electronic game
(such as
one that may be found in a casino) operating in a single cell configuration
and attached to
some central server. However, it is noted that as described above, examples of
applications
and uses are for purposes of illustration and clarity and do not limit the
present invention.
[00172] The game has a resident RDC integrated into its hardware and has a
system
stack that allows access to the game. The RDC may be attached to the game
controller, or
may use a separate controller containing the system stack and an interface to
the central
CA 02636167 2008-07-03
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server.
[00173) For clarity, any interactions between the RDC and the server will
assume that
the reader understands that the system stack and server interface application
are taken into
account in the transactions described.
[00174] This description covers the basic initialization of the system and RDC
/ PDK
interactions that occur while associated in the system. The following concept
defines how,
for example, a casino game in a single cell configuration may be setup with
multiple player
PDKs. Upon power being applied to the game and RDC, the internal circuits
perform an
initialization function and the operating system and game load. The game and
RDC indicate
to the central server that power has been applied. The system stack also loads
in the
controller and the RDC device is started in a static mode with its transceiver
disabled. The
RDC may first be configured to operate in a single cell environment and
requires some basic
setup requirements as will be understood by those skilled in the art.
[001751 The server places the game into a particular configuration mode where
it can set
the RDC for auto-discover mode, or may choose to manually configure parameters
related to
the RDC's operation. If the server places the RDC into auto-discovery mode,
the RDC
generates a random value for its RDC ID and its password, which is then passed
back to the
server.
[001761 If the server chooses to manually setup the RDC, the server may supply
the RDC
ID and password. The server may also send the network topology and preferred
channels the
RDC will.operate on. The central server may then send its site information to
the game
controller, which is also used by the RDC to allow access to the game. Once
the server has
configured the RDC, the server will enable the RDC and game.
[00177] The configuration information shown in the table immediately below may
be
used for RDC provisioning.
Site ID Ox0100 Generic value for a single cell RDC.
RDC ID Ox1234 Arbitrary value
C-Superframe Length 32 2.5 second 'superframe period for PDK
wakeup
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Superframe Length 16. 16 slots per superframe
Proxense Network Proxense Defines system as a Proxense system
Identifier
Proxense Network Format
Network Type 0 Single Cell
Beacon Source 0 RDC
Broadcast Flag I Broadcast
Timeslot Select 1 802.15.4 timeslots
[00178] In this configuration of a standalone RDC (without a site identifier):
the site ID
is set to 0 because this is a single cell RDC and no site information is
required; the RDC ID is
arbitrarily selected; the c-superframe length is set to 32 superframes
indicating to the PDK
that it needs to wake up once every 32 superframes in superframe 0 to exchange
information
with the RDC to remain associated; the superframe length is set to 16, which
may be the
standard value for a superframe in a particular system; the network identifier
allowing a PDK
to understand the beacon is from an enabled RDC; and the network format
indicates one or
more of several parameters (e.g., the network type indicates to the PDK that
it is a single cell
network - indicating to the PDK no other RDC is associated with this RDC and
therefore no
other RDC should be attempting access on this channel, the beacon source
indicates to the
PDK that the beacon is from an RDC and not a CRDC device, the broadcast flag
indicates to
the PDK that the message is being broadcast from the RDC, the timeslot select
field indicates
that a PDK should use IEEE 802.15.4 beacon-based handshaking with the RDC).
The RDC
then scans all channels (or preconfigured channels) to determine if any other
IEEE 802.15.4
or client devices are present or if any other interference is found.
[001791 With the pre-configured information, the RDC then begins beacon
transmission
on the least interfered channel with a c-superframe count, superframe count,
and the
information located in the table immediately described above.
[00180] Now, as shown in Figure 25, in standalone mode, the RDC will continue
to
transmit beacons on every superframe. The information in the table immediately
described
above may be transmitted along with the superframe count in every superframe
to allow the
PDK to configure and synchronize with the system. When the superframe count is
the
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superframe length minus one, the superframe count will start counting from 0
for the next c-
superframe.
[001811 At the end of each beacon transmission, a frame check sequence (FCS)
may be
appended as part of the IEEE 802.15.4 physical layer. The FCS provides
protection for the
data carried in the frame. Because the beacon may not occupy the entire frame*
(or timeslot),
hashed lines are shown indicating additional idle time between the FCS and
IFS. The RDC
maintains the beacon transmission until the RDC is disabled or power is
removed. At this
point in the sequence of operations, there are no PDKs registered with the
RDC, so no PDK
can gain access without registering and receiving authorization from the RDC.
[001821 Again referring to the casino game example described above, a player
with a
PDK that has not yet been registered to the property enters the RDC cell. The
PDK is in
battery save mode and periodically wakes up looking for a network. As shown in
Figure 26,
the PDK starts in a deep sleep state. The wakeup timer eventually expires,
causing the PDK
to enable and tune its receiver. The PDK then monitors the channel that it
tuned to for a
period of one 17 timeslots (one superframe plus one slot), or approximately 83
milliseconds.
The 17 timeslot limit is based on a superframe of 16 timeslots, and the fact
that the PDK,
upon initial reception, could miss the beginning of a beacon. The additional
slot provides the
overlap necessary to guarantee reception of a beacon if one is present.
[00183] If no beacon is detected, the channel number is incremented (modulo
16) and the
PDK resets its wakeup timer and returns to deep sleep mode. If a beacon is
detected, the
PDK checks for a network ID and if one is not found, it again increments the
channel number,
resets its wakeup timer, and returns to deep sleep mode. If the network ID is
detected, the
PDK attempts to establish a communications link with the RDC. At this point,
the PDK has
found a single cell network on channel 1 with an RDC ID of 0x1234, and the RDC
is in
broadcast mode indicating that it is attempting to gain the attention of any
PDKs in the local
proximity.
[00184] Now referring to Figure 27, in which an authorization denial handshake
is
shown, the RDC broadcasts its beacon with the information as described above.
The PDK
detects the beacon in broadcast mode, determines the network configuration and
RDC ID and
returns a PDK location response with the RDC ID and PDK ID included. The RDC
detects
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the response from the PDK and alerts the central server that a PDK with a
public ID of
0x9876 (arbitrary) wants to attach and enable the game for play. In the
meantime, the RDC
may immediately respond back to the PDK indicating that the PDK should wait
for
authorization. This keeps the PDK responding to beacons as defined by the
fields located in
s the beacon until the beacon is no longer present (i.e., the PDK is no longer
in the RDC cell),
or until a response is returned by the RDC.
[00185] The central sever, in conjunction with the system stack, may then
choose to not
recognize a particular PDK's public ID that has not yet been registered to the
property. The
RDC continues to output its beacon. Upon the next wakeup and PDK location
response from
the PDK, the RDC detects the PDK ID and, within its database, looks up the
authorization
parameters for this PDK. It determines that authorization has been denied and
sends an
"authorization deny" command to the PDK. In the case that a particular PDK is
not
recognized or not authorized, a notification may sent to a staff member of the
property to
register a user of the PDK, and/or, in one or more embodiments, one or more
machines may
be used to prompt the user to register with the property.
[00186] The PDK temporarily stores the RDC ID in its local memory with a flag
indicating that it shall no longer respond to this RDC ID. The PDK may then go
back into
battery save mode and periodically scans all charmels as previously described
above with
reference to Figure 26.
[00187] Still referring to Figure 27, because the PDK may not constantly be
aware of its
geographical location, the PDK may continue to monitor each channel and decode
each
beacon. Eventually, the PDK returns to the channel that the RDC is still
transmitting beacons
on, decodes the beacon information including the RDC ID, and determines that
it is not to
respond.
[00188] Further, the PDK may maintain the RDC ID in its local database until
the
beacon is no longer present during scanning, at which time the RDC ID is
removed from the
database. The period of time that the beacon is absent before removing the RDC
ID from the
database may be determined during prior system testing.
[00189] Assuming the RDC beacon is absent for a given period of time indicates
to the
PDK that the PDK has left the RDC cell. Upon the next detection of that RDC
beacon, the
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PDK may again attempt to gain access to the RDC as shown in Figure 27. The
difference this
time is the PDK ID is in the RDC's local database and the RDC may deny
authorization
without alerting the host system. The PDK may then operate as previously
described after
authorization has been denied.
[00190] In one or more embodiments, once a host system grants authorization
for the
PDK to operate within the property, then one or more different scenarios may
exist. In one
scenario, the RDC may transmit the PDK ID as part of the beacon transmission,
alerting the
PDK that the RDC wants to communicate, and the PDK may then respond with a PDK
location response. In another scenario, the PDK returns to the RDC cell, and
after detection
of the beacon (with or without the PDK ID), it retums the PDK location
response. In either
case, after the RDC detects the PDK location response with the PDK's public
ID, the RDC
then issues a link request attempting to initiate a link between the RDC and
PDK. Figure 28,
for example, shows a handshake between the RDC and PDK for a PDK authorization
grant.
[00191] As shown in Figure 28, the RDC may broadcast the beacon on every
superframe.
Although not shown, the superframe counter value is also included, which the
PDK may use
for battery conservation. The beacon may be broadcast in one of more different
methods.
The system may have just authorized a PDK and the beacon includes the PDK's
public ID for
a period of time or, in another method, the beacon may be transmitted without
the PDK's
public ID. As described above, if the PDK is in the RDC cell and has
deactivated its
response, when the PDK detects its ID in the beacon, it may reactivate its
response to the
RDC and transmit both the RDC ID and PDK public ID in its PDK location
response.
[00192] If the PDK has just re-entered the RDC cell and detects the RDC beacon
(with
or without the PDK's public ID), the PDK may again respond with the RDC ID and
its own
PDK public ID. The RDC may then detect its RDC ID and the PDK public ID and
immediately sends a link request to the PDK with both its RDC ID and the PDK's
public ID
indicating it wants to initiate a link with the PDK. The PDK may detect the
request and
respond with a link grant with both IDs included. The RDC and PDK may enter
into
association mode and then provide data exchange on a periodic basis insuring
the PDK
remains in range of the RDC. This periodic data exchange may occur based on
parameters
previously described above. Interleaved between the data exchange may be
beacons that
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other PDKs may use to access the RDC. Eventually, the RDC may terminate the
data
exchange based on inactivity, as determined by the server, or as based on the
PDK leaving the
RDC cell, in which case the RDC realizes the PDK is no longer in range.
[001931 Further, it is noted that due to radio interference issues that might
occur in
wireless systems, the RDC and PDK may not relinquish the link based on the
lack of a single
data exchange. Because the RDC is not necessarily battery limited, the RDC may
continue to
monitor all timeslots in a superframe with the exception of those frames it
transmits on. In
contrast, it is noted that a PDK is likely battery limited and therefore may
need to intelligently
choose when to receive and transmit.
[00194] In the case the RDC and PDK lose communications during the predefined
period
they are attempting to communicate, both devices may have equal knowledge of
such an
event. Because the PDK is battery limited, the PDK may try on the next
available timeslot to
regain synchronization with the RDC. After a period of time in the RDC, or a
predefined
number of attempts by the PDK, the link may be considered lost.
[00195) Referring again to the casino game example, in one or more
embodiments, an
enabled single cell game facilitates multi-player access via the central
server. Individual
players may consecutively play the game provided they have the appropriate
PDK, or in some
instances, multiple players may be able to simultaneously play the game. The
RDC allows
for simultaneous multi-player access, so long as the central server supports
and authorizes
such play.
[001961 In the case where multiple PDKs may simultaneously access an RDC, the
RDC
may provide superframe coordination information to the PDKs to interleave them
in a manner
to avoid contention between RDC and PDK communications. For example, as shown
in
Figure 29, the RDC may assign a superframe and timeslot count to each PDK
accessing the
RDC. Through link setup and data exchange, the RDC may direct the PDK to use a
specific
superframe and timeslot (or multiple superframes and timeslots) for periodic
data exchange.
By using such a technique, the RDC may alter the wakeup superframe for each
PDK and may
efficiently distribute them so as to reduce contention between the PDKs.
Because the PDKs
are given a specific superframe and timeslot (or superframes and timeslots),
the PDK is
required to wake up during that superframe(s) and timeslot(s) to communicate
with the RDC.
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This technique, in turn, may greatly extend PDK battery life.
[00197] Now referring to Figure 30, it shows a configuration in which multiple
games
operating as single cell RDCs are co-located in close proximity with
overlapping RDC cell
coverage. In such a configuration, each RDC 200, 202 may not be aware of the
presence of
the other RDC 200, 202 but a PDK 204 that resides in the area of overlapping
coverage may
detect the presence of both RDCs 200, 202. A technique of restricting or
allowing PDK
access to one or more of the RDCs 200, 202, and the technique of enabling game
play may
depend on the system stack for that specific configuration.
[00198] In a configuration where multiple RDCs are co-located without the
knowledge
of each other, and where a PDK is registered to both RDCs, a technique of
determining and
gaining access to each RDC may be enforced. There are one or more possible
scenarios that
may occur. For example, in one case, a player may desire'simultaneous access
to a game and
another device, sucli as a drink or food purchase device, with both being
physically located
near each other and without disrupting the game play. In another case, a
player may be
registered to multiple RDCs, but wants to associate with one RDC at any given
time.
[00199I In addition to an RDC granting permission to the PDK for access, the
RDC may
also dictate to the PDK the number of simultaneous associations allowed. The
purpose of
defining the number of associations permitted may reduce the possibilities
that the PDK can
sirnultaneously associate with and enable two or more RDCs within close
proximity of each
other. This may prevent unauthorized use of a player's PDK on adjacent enabled
devices,
thereby disallowing a player from using another player's identity. The
capability of
configuring the number of associations for a particular RDC may be implemented
in a system
stack and controlled by the attached controller's application.
[002001 Referring again to the case where a player desires simultaneous access
to a game
and another device, a PDK may be capable of associating to multiple RDCs based
on the
physical limitation of the maximum number of simultaneous connections the PDK
can handle
and based on the number of associations the RDC permits.
[00201] Further, it is noted that under the conditions the PDK is associated
with more
than one RDC, the PDK may relay information back to each RDC indicating its
timing
relative to the other RDC. This information may be important in the event a
single PDK is
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associated with more than one RDC because the clock frequency error between
the RDCs
may cause eventual timing drift that will eventually cause timeslot and
superframe overlap
and prevent the PDK from communicating with both units on a periodic basis.
This situation
is also noted: where two PDKs -are associated with the same RDC and each PDK
is also
associated with a different second RDC. Additionally, each of the second RDCs
may also
have other PDKs associated with 'them that are also associated with even
different RDCs.
Eventually, such an uncoordinated system may appearing like a mesh network. A
system of
such complexity may require a CRDC to be used to address synchronization
issues.
[00202] As to the case where a player may be registered to multiple RDCs, but
wants to
associate with one RDC at any given time, there may one or more techniques
that may be
employed to control how a PDK associates with a specific RDC. In one way, a
PDK is
associated with a single RDC. Using this technique, the PDK may attempt to
associate to
other RDCs, but the other RDCs will deny association through the back-end
central server,
causing the PDK to ignore the other RDCs as previously described above. It is
noted that
such a technique may eliminate a cell size issue, where the cell must be
constrained to prevent
other RDCs the PDK is registered to from accessing the PDK_
[00203] In another technique for directing a PDK to communicate to one RDC in
a
configuration where multiple RDCs exist of which the PDK is registered to, by
significantly
reducing the RF power level from the RDC and providing this information along
with a
request for the PDK to reduce its RF power, a close proximity cornmunications
channel may
be created. The close proximity communications channel may then operate as if
a single cell
network exists. More particularly, if the RDC is configured to have a reduced
RF power
output, the RDC's cell boundary shrinks causing the PDK to have to be within
closer
proximity of the RDC to receive a beacon from that RDC. If, in turn, the RDC
indicates in
the beacon that it is at reduced RF power, the PDK is aware that the RDC is in
extremely
close proximity. In addition, if the beacon includes a command to instruct the
PDK to reduce
RF power, the chance of surrounding RDCs receiving a response or interference
from the
PDK may be minimized. When the communications channel is terrninated. and the
PDK no
longer sees the beacon from that RDC, the PDK may readjust its RF power level
to normal
levels for a larger cell coverage area. Such dynamic RF power level adjustment
may be
implemented in the system stack.
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[00204] Thus, in one or more embodiments, there exists a scheme to dynamically
adjust
a transmission power and/or reception sensitivity of a wireless reader device
along with an
ability to command a client device to do likewise to permit both cell coverage
and client
device response area programmability. This may enable the dynamic tracking of
transient
client devices within and through the cell's extended or default coverage area
with full power
and sensitivit.y at both ends, while concurrently allowing the association of
a particular client
device in close proximity to the reader device for command and control of an
application or
service during a session. Those skilled in the art will note that by
dynamically varying a size
of a cell in which a secure transaction takes place between a PDK and an RDC
(or in which a
PDK accesses an application via an RDC), at least some level of security may
be achieved in
that eavesdropping may be prevented. Moreover, unnecessary and potentially
unsafe
propagation of a wireless signals beyond a certain distance may be avoided.
[002051 For example, a plurality of PDKs may be located in a default wireless
coverage
range of an RDC. This default wireless coverage range may represent a cell of
the RDC at
full power. As the plurality of PDKs enter and exit the RDC's cell, the RDC
reports
corresponding location tracking information back to, for example, a central
server. When one
of the PDKs requests access to an application secured by the RDC, the RDC may
follow by
reducing its RF power and commanding the requesting PDK to also lower its RF
power,
thereby in effect requiring that the requesting PDK be "drawn in" to the RDC
in order for the
PDK to access the application. It is noted that while the RDC may communicate
with the
requesting PDK via low power RF signals, the RDC may continue to maintain its
default
wireless coverage range for tracking other PDKs. When the requesting PDK is
moved away
from the RDC or the session is otherwise terminated, both ends return to their
default full RF
power settings.
[002061 As described above, reception sensitivity of the RDC and/or PDK may be
changed as part of a cell size variation technique in accordance with one or
more
embodiments. Reception sensitivity may be adjusted using an RF attenuator
(e.g., a step,
variable, or programmable RF attenuator) that is either specific to a receive
path or common
to both receive and transmit paths. It is noted that even= if the attenuator
is common to both
receive and transmit paths, transmit power may be independently controlled.
Further, in one
or more embodiments, a separate attenuator may be used to allow for
independent control of
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transmission power and reception sensitivity.
[002071 To determine how much to adjust the size of a wireless cell without
severing a
wireless connection between an RDC and a PDK, one or more of various metrics
may be
used. For example, in one or more embodiments, a signal strength of the PDK
may be
monitored to determine by how much to power down a transmission power of the
RDC
and/or the PDK. If the signal strength is determined to be relatively strong,
then the RDC
may cause a reduction in transmission power that is greater than if the signal
strength were
detected as being weak. Conversely, if the signal strength is detected as
being weak, the RDC
may lower transmission power by a small amount or not at all. Instead of or in
addition to
relying on signal strength, a bit error rate may be assessed to determine by
how much to
power down the transmission power. For example, if the bit error rate of
communications
between the RDC and PDK is determined to be low, then the RDC may lower
transmission
power by an amount greater than if the bit error rate was determined to be
relatively high.
[00208] -Further, as described above, the transmission power and/or reception
sensitivity
1.5 of either or both of an RDC and a PDK may be adjusted. In one or more
embodiments, only a
transmission power of the PDK may be adjusted. This may done to, for example,
"bring in"
the PDK and reduce the likelihood of that PDK interfering with other RDCs. In
one or more
other embodiments, the transmission power of both the RDC and the PDK may be
adjusted in
an effort to draw in the PDK to the RDC. In still one or more other
embodiments, in addition
to or instead of adjusting transmission power, reception sensitivity of either
or both of the
RDC and the PDK may be changed.
[00209] Moreover, in one or more embodiments, an RDC may have multiple
wireless
transceivers, whereby at least one of the transceivers is at full power for
PDK location
tracking purposes, while orie or more of the other transceivers are used to
establish adjustable
wireless cells for particular associations with PDKs. For example, in the case
of an ATM
machine having an RDC, the RDC may carry out a secure transaction with a PDK
in an
adjusted wireless cell, while at the same time, casting a broader wireless
cell to monitor and
identify one or more PDKs around the transacting PDK. In such a manner, for
example, a
security measure may be implemented by which the RDC can identify individuals
behind a
transacting user. Further, as an added or alternative security measure,
transmission power
CA 02636167 2008-07-03
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may be adjusted dependent on a sensitivity of the type of data requested to be
exchanged in a
particular transaction. Such data sensitive transactions may be conducted at
low power with
additional security measures such as password entry or biometric input.
Application Utilizing Multi-Cell Coordination
[002101 The following describes a system architecture and operation of a
system within,
for example, a casino application. Referring to Figure 31, a CRDC (not shown)
and multiple
RDCs (shown, but not individually labeled) are distributed throughout a casino
floor. In =such
embodiments, a single CRDC generates a cell 210 that provides ubiquitous
coverage of the
entire floor. On the left side of Figure 31, multiple RDCs (shown, but not
labeled) provide
overlapping cell coverage and blanket the casino floor and gaming table area
212 all the way
to an entrance of the casino with continuous wireless service coverage. These
RDCs may be
dedicated to PDK location tracking, allowing the casino operator to know where
a player
carrying his/her PDK is geographically located on the floor. These RDCs may be
mounted in
the floor or ceiling, creating, for example, relatively symmetrical cells.
[00211] Another set of RDC cells (showin, but not labeled) are shown to exist
in the right
side of Figure 31 and are integrated in gaming machines (shown, but not
labeled) within an
electronic gaming area 214. The cell orientation for these RDCs is more oblong
and focused
at players that are within close proximity and in front of the electronic
gaming machines,
noting that cell orientation and shape may be set according to antenna
position and/or
configuration. The cells extend outward towards the center of the isle to
detect the presence
of a player that may be walking by. Toward the lower right part of Figure 31
is a registration
cell 216 that sits at a registration desk (shown, but not labeled) where a
player may register
and acquire a PDK the first time the player enters the casino. The
registration cell 216 may
be smaller in size to enable local communications between the RDC and PDK
without
2.5 allowing extemal RF monitoring devices to capture and record the
interaction between the
devices.
[00212] It is noted that in Figure 31, a PDK 218 that is currently out of the
range of all
RDCs, but still in range of the CRDC. This represents a PDK carried by a
player, which is
being used to track the player's position and provide additional services.
Such services are
further described below.
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[00213] Further, still referring to Figure 31, there is a central server 220_
The central
server 220 may contain a player's financial information (credit card numbers,
gambling
limits, and other information related to a player). In addition, the central
server 220 may be
physically wired (not shown) to all RDCs andlor CRDCs located throughout the
casino.
[00214] Although not shown in Figure 31, within the PDK location tracking
system,
RDCs may be gambling tables that also have RDCs embedded within the table
itself. A
representative gambling table is shown in Figure 32.
[002151 As shown in Figure 32, a gambling table 230 has RDCs 232, 234, 236,
238, 240,
242, 244, 246 embedded within it. RDC 246 may be a dealer RDC that has a cell
geometry
covering the dealer's area, allowing the dealer to freely move around in this
area. There are
an additional RDCs 232, 234, 236, 238, 240, 242, 244 that are located at each
player position.
Each of these RDC cell's coverage areas are oblong and are directed to where
the player
would be sitting/standing. It is noted that each player position's RDC 232,
234, 236, 238,
240, 242, 244 allows for some coverage of the region directly behind each
player position,
allowing the RDC 232, 234, 236, 238, 240, 242, 244 to report back through the
system the
presence and identity of anyone behind the player. The RDC cell's coverage
areas may be
minimized to cover the area where a dealer or player may be located relative
to the table.
Those skilled in the art will note that the actual cell footprints may vary
from those shown in
Figure 32. Utilizing distributed RDCs with directional, highly attenuated,
antennas allows the
casino operator to know the location of both dealers and players, and the
amount of time they
remained at the table.
[00216] The CRDC, PDK location tracking RDCs, and gambling table RDCs, may
interoperate in a system such as that shown in Figure 33. Figure 33 shows a
graphical
representation of the sequence of events that may occur when a c-beacon is
transmitted in, for
example, a casino application. As shown in Figure 33, first, a CRDC 250
transmits the c-
beacon to all RDCs and PDKs (shown, but not labeled) within the CRDC's cell
radius. All of
the RDCs and PDKs setup and synchronize their timing to the beacon. Next, each
PDK, in its
appropriate timeslot, transmits a PDK location response ID. Any RDC that is in
the vicinity
of the PDK's response receives the PDK location response ID and logs specific
information
related to the reception. Then, each RDC packetizes the information received
from the PDK
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and, through a wired back channel, relays the information to a central server
252. The central
server 252 may then utilize this information to indicate to an operator, by
either graphical or
text format, the geographic location of each player.
[00217] Representing the flow in a different manner, the interactions for a
single PDK is
shown in Figure 34. -In addition to providing location tracking information,
when the PDK
outputs a PDK location response ID, certain events may occur from an RDC based
device. In
the event the RDC based device is an electronic game, via the central server,
the electronic
game may entice the player over to it by flashing information on the screen
related to that
specific player. In one example, an electronic gaming machine may offer the
player a free
game, gaining the player's attention and ultimately enticing the player to
play the game. In
order to identify the player, further steps may be taken between the PDK and
the RDC that are
described below.
[002181 In the event the RDC device is used for location tracking, it may
perform further
interrogation of the PDK to determine whether the PDK is legitimate. A more
detailed
description of such interrogation is provided below.
[00219] Now referring to Figure 35, it shows two CRDCs with overlapping cell
coverage, but not to the poiht where each. CRDC can see the other CRDC. As
shown in
Figure 35, the CRDC cells are non-uniform in nature due to obstructions
blocking the
transmit radio path. The CRDC cell overlap may cause a number of RDCs to be in
each
CRDC cell. It is envisioned that other CRDCs may overlap in the same region if
they are
placed above and below the RDC micro-cellular structure. In this case, for
example, up to 4
channels may be occupied just for CRDC beacon transmission.
[00220] Due to the possibility of interferers in the coverage area of the
CRDC, the'
central server may manually configure the CRDC, or the central server may also
instead or
additionally have the capability to auto-configure. In the case the central
server performs
manual configuration, upon initial installation, power up, and provisioning,
the CRDC is
configured to remain in a dormant state until the central server interacts
with the device and
instructs it to perform specific tasks. The central server may first instruct
the CRDC to enable
the receiver, scan all channels, and report back the findings of each channel.
When the
CRDC scans each channel, it collects signal quality metrics and any IEEE
802.15.4 radio
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transmissions. The operator of the central server may then analyze all of the
signal quality
metric information and any IEEE 802.15.4 framing information to determine the
best channel
the CRDC should transmit its beacon on. Once determined, the operator at the
central server
may command the CRDC to store the specific channel that it will transmit on
and enable it to
S begin transmitting. The operator may then select the next CRDC and perform
the same
operations, until all CRDCs have been configured in the network.
[00221] In an automatic configuration mode, the CRDC scans each channel and
collects
signal quality metrics and determines if other - IEEE * 802.15.4 devices
(including another
CRDC) are present. The CRDC may then select the quietest channel to begin its
beacon
transmission on. Further, it is noted that it may be recommend that initial
auto-configuration
of a CRDC occur when there is a single CRDC present. This recommendation is
based on the
fact that the CRDC may have overlapping coverage with another CRDC as shown in
Figure
35, but the CRDC is not aware of the overlap, causing two CRDCs to transmit
their beacons
on the same channel. Eventually, due to potential timing inaccuracies in the
CRDCs, they
may overlap and become direct interferers to RDCs and PDKs in the overlapping
area. An
exception to this recommendation is when the system is configured to allow the
CRDC to
report back the channel that it occupies (or intends to occupy) to the central
server, and the
server can then analyze the CRDC channel lineup on all CRDCs and reassign a
channel for
any given CRDC.
[00222] Once a channel has been assigned and stored in a local non-volatile
memory of
the CRDC, upon next power up, the CRDC scans all channels again and return to
their last
assigned channel provided that it is not occupied by an interferer or by
another CRDC
beacon. In such a case, the CRDC may have to again go through the
initialization process.
[00223] Although a synchronized system may lead to higher. , throughput and
may
possibly lead to better battery life, in one or more embodiments, it may not
be necessary for
CRDCs to be synchronized. Because each CRDC operates on a separate channel,
there may
be no timing-specific consideration that needs to be addressed between CRDCs.
Instead, a
concern may relate to how the PDK aligns to multiple unsynchronized CRDCs.
From a PDK
location-tracking standpoint, the PDK may be required to lock to a single CRDC
beacon. The
CRDC beacon will indicate to PDKs what other channels a CRDC may be located
on. The
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PDK may not need to attempt receiving from any other CRDC, provided the signal
quality
metrics for the current CRDC it is monitoring has sufficient signal quality to
receive error
free data. In the case the signal quality degrades, the PDK may then
periodically switch to
other channel(s) to determine if a better signal quality can be obtained. If a
better signal
quality is determined to be on an alternate channel, the PDK may then
immediately switch to
the alternate channel, provided it is not in association with an RDC at that
instance in time. If
the PDK has begun association to an RDC, the PDK may have to attempt to finish
the
association before switching to the alternate channel. It is noted that once a
PDK is in
association with a RDC, the PDK is no longer required to monitor the CRDC
beacon, until
the association ends between the devices by releasing the link or by the PDK
leaving the RDC
cell.
[00224] When an RDC is powered up for the first time, the RDC may not be aware
of the
network it belongs to or its configuration within the network. The RDC may
default to a
single cell configuration. For this reason, -RDCs placed in a CRDC cell
configuration may by
default remain in a dorrnant state upon its first initial power *up in the
network. This may
allow the central server to configure any specific information related to the
network into the
RDC prior to operation. Some of this information may include, for example, the
site ID, a
local RDC ID, and other parameters related to the wireless transmission
protocol. The site ID
is important, because the property owner may not want their RDCs to become
associated with
another property; thus, the RDC should synchronize to beacons transmitted with
that site's
ID. The RDC ID is used in communication between a PDK and RDC; hence, there
should be
one RDC ID per RDC device in the network. Other application-dependent
parameters may
include how the unit operates when associated with a PDK and whether the RDC
sends data
back to the server when data is ready, or if the server must poll the RDC for
the information.
The central server may then command the RDC to enable its receiver and scan
all channels to
determine the signal quality of each channel and which CRDCs may be received
by the RDC.
The operator of the central server may allow the RDC to automatically, select
which CRDC
Beacon to lock to, or can command the RDC to select a specific CRDC beacon.
After
reviewing the channel list for signal quality, the system may then command
which channels
the RDC can use for alternate channels for RDC-PDK communications, or the
system may
command the RDC to automatically select the alternate channels. The system may
then place
CA 02636167 2008-07-03
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the RDC in operation mode, and the RDC then tunes to the selected CRDC beacon
channel
and remains there listening for CRDC beacons and any PDK that sends a PDK
location
response ID. While receiving the c-beacon, the RDC may configure its timeslot
information
similar to that described above. This defines the superframe structure as well
as defining
which timeslots (odd or even) the RDC is permitted to communicate with a PDK
on the
beacon channel.
[00225] In the background, on the alternate wireless link described above with
reference
to Figure 9, the RDC may continue to scan the alternate channels, updating its
list of clear
channels. This updated list may then be used when a RDC determines it wants to
extend its
communication with a PDK in association mode and selects which channel that
communication will occur on. The RDC, in operational mode, may perform frame
and slot
alignment to the CRDC and listen for a PDK location tracking response. On a
periodic basis,
the RDC may send information back to the central server indicating that it is
still operational
and indicating the status of the communications channels (e.g., CRDC beacon,
alternate
channels).
[00226] In one or more embodiments, a registration RDC may be used to
initially enable
and to configure a PDK. The registration RDC may have a small cell coverage
area by
design, measured, for example, in inches. This may require that the
unregistered PDK must
be in extremely close proximity, e.g., placed on the registration RDC housing,
to
communicate with the registration RDC, reducing the likelihood of RF
eavesdroppers gaining
access to PDK setup infornzation.
[00227] The registration RDC may be directly connected to a central server. In
addition
to specific security features, the registration RDC installs and configures
service provider
information located on the central server (described above with reference to
Figures 6 and 7).
Such information may include the service provider ID, secret key, and other
parameters that
the service provider wants to designate for access within their network. These
other
parameters may vary in size in the PDK and may be defined by the host system
to meet the
needs of the property. Information transferred to a PDK may include, for
example, the
service provider site ID, the service provider's assigned PDK ID, the service
provider's secret
service ID, the service provider's secret key, and service provider specific
access infornlation.
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[002281 Now describing an example of an operation in accordance with one or
more
embodiments, once a system has been installed and properly provisioned, a
rated player may
walk into the casino. They are greeted by a host and walked over to the
registration desk,
where the player's information, already in the central server, is linked to a
PDK that is given
to the player and assigned with specific privileges. The player places the PDK
in their pocket
and begins to walk throughout the casino. Once the PDK leaves the registration
cell, the
PDK enters discovery mode and scans the channels for a c-Beacon. If the PDK
does not
locate the c-beacon, it continues to scan for an undetermined period of time
until it either goes
into battery save mode or finds a c-beacon.
[00229] Once the PDK finds a c-Beacon, the PDK determines if the c-beacon is a
particular type of network and the site ID is in its local service provider
database. If the site
ID is not in the= database, the PDK ignores that c-beacon and keeps looking
for other c-
beacons on other channels until one is found that is in its local database.
Once a valid c-
beacon containing a site ID that is in the PDK's local database is found, the
PDK extracts the
CRDC channel availability flags and checks the other channels in the CRDC
channel
availability list. The PDK then determines which CRDC has the best signal
quality metrics.
The PDK switches to that channel and begins receiving c-beacons. The PDK
extracts the
CRDC and network configuration inforrnation as described above. This
information may
define the framing structure and how the PDK should operate within the
network. The PDK
then applies the c-beacon parameters to its radio transceiver parameters,
configuring the sleep
interval and response superframe and timeslot information. Because the PDK has
just
received a c-beacon, the PDK is now aware of the current superframe count. The
PDK then
configures its timer to wake up just prior to the expected superframe count
that it may
communicate on.
[00230] Now also referring to Figure 36, when the sleep timer expires, the PDK
may
wake up, listen for a specific c-beacon, and -verify the superframe count. It
then waits a
predetermined period of time for its slot to be available and performs CSMA-
CA, and if no
other device is attempting to respond, it responds with its PDK location
tracking response. If
another device was detected on the channel, the PDK may then reset its timers
and wait for
the next predefined superframe and timeslot to wake up and attempt again.
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[00231] It is noted that a PDK in accordance with one or more embodiments may
be
powered by an internal battery of, for example, a type commonly used to power
small
electronic devices such as watches, calculators, and mbbile computing devices.
The power of
such a client device battery is consumed when the PDK is active. In an effort
to reduce
and/or minimize battery consumption, in one or more embodiments, the active
time of a PDK
as a percentage of total time may be reduced by management of transmission and
reception
times_ For example, as described above, a network in accordance with one or
more
embodiments may be designed to configure time slots (e.g., frames), groups of
time slots
(e.g., superframes), and/or coordinating beacon superframes (e.g., c-
superframes) in a manner
such that a client device is caused to both listen and respond within specific
time slots.
Because these time slots are configured by the network, they may be precisely
predicted,
thereby allowing the client device to set a timer, return to sleep mode, and
waken when a
specific, time-slotted interaction is expected or required of the client
device. Further, in one
or more embodiments, because a network in accordance with one or more
embodiments may
ls implement programmable c-superframe lengths, an operator or system may
individually tailor
performance to maximize (or at least improve) battery life and/or minimize (or
at least
reduce) system inter-message latency without requiring access of the client
device itself or
physical alteration of the client device.
[00232] When the PDK responds with a PDK location tracking response, every RDC
within local proximity that can receive the response may log the response
message in its
database along with signal quality metrics and a timestamp. They will then
send the
information back to the central server. The response may be sent by the server
polling the
RDC or by the RDC if it has data to send. Once the central server receives the
PDK
information from one or multiple RDCs, the server may then determine if any
further
communication with the PDK is necessary. If, for example, the system wants to
validate the
PDK, it can perform a validation. The server may then send a command to a
specific RDC to
set up communications with a specific PDK and wait for a response from that
RDC. Because
the communication between the RDC and the central server may not be
instantaneous, the
RDC may have to wait for the next PDK location tracking response. After
performing
CSMA-CA, it may immediately instruct the PDK to switch to the altemate
channel. If,
during the CSMA-CA, the RDC detected another device on the channel, the RDC
may wait
53
CA 02636167 2008-07-03
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for the next PDK location tracking response from that PDK and then re-attempt
PDK channel
reassignment. The PDK may then switch to the altexnate channel, perform CSMA-
CA, and
send a link request to that specific RDC ID with its own ID included. The RDC,
looking for
the link request with its specific ID and a particular PDK ID, detects the
request and then
responds with a link grant. Further, the RDC may alert the central server of
the link, and a
data exchange occurs with information the server is interested in collecting
by interrogating
that PDK. After the data exchange occurs, the central server commands the RDC
to terminate
the link. The RDC may then terminate the link, and the PDK may returns to the
c-Beacon
channel, re-synchronizing to the beacon, and begin monitoring for its
timeslot. The PDK may
then continue to send responses back to all RDCs in its immediate vicinity
when its specific
superframe count and timeslot are valid.
[00233] It is noted that the foregoing description detailing a process of PDK
validation
and interrogation relates to one or more embodiments. However, in one or more
other
embodiments, the central server may have also altered the service provider
information within
the PDK.
[00234] If, during the switch to the altemate channel for RDC to PDK
communications,
the PDK determines the channel is occupied or the PDK does not receive a link
grant back
from the RDC, the PDK may perform one or more additional attempts. If after
all attempts,
the PDK does not receive a response from an RDC, that PDK may return to the c-
beacon
channel, realign to the beacon, and then begin sending its PDK location
tracking ID.
[002351 If the RDC was unable to receive the link request from the PDK on the
alternate
channel, for a predefined period of time, the RDC may flag the error and
continue listening on
the channel. If the same RDC is again instructed to establish communications
with the same
PDK, the RDC may choose to use a different altemate channel and redirect the
PDK to the
new alternate channel for communications.
[002361 Now referring to Figure 37, it shows a PDK wakeup and response flow in
a
CRDC coordinated system. For purposes of describing Figure 37, it is assumed
that the PDK
has acquired system synchronization and has gone into the sleep mode after
setting its timers
to wake up on the next predefined superframe. The PDK remains in sleep mode
until the
wakeup timer expires and wakes up the PDK. The PDK then enables and tunes its
receiver to
54
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the c-beacon channel and listens for the beacon for a predefined period of
time. If no beacon
is detected, the PDK checks for other CRDC channel available flags in its
local memory. It
then reassesses signal quality and beacons on the alternate CRDC channels.
[002371 After the PDK assesses the other CRDC channels and no beacon is found,
the
-PDK goes back into rediscovery mode scanning all channels looking for a c-
beacon. If no c-
Beacon is found, the PDK then starts its deep sleep mode. In the event that
other CRDC
channels are present, the PDK assesses the signal quality of each channel and
selects the best
channel. The PDK then selects that channel and tunes to it listening for the
CRDC beacon.
[00238I - When the PDK receives the beacon, it checks all of the parameters
associated
with it including the superframe count. If the PDK determines the superframe
count is not the
correct one for it to wake up and respond on, it sets its internal sleep timer
to wake up just
before the next expected superframe it should respond to and returns to sleep
mode. If the
PDK determines that the beacon is on the PDK's expected superframe count, the
PDK then
stays awake, but stops listening until just before its expected timeslot. The
PDK may then
perform CSMA-CA to determine if the channel is busy. If the PDK determines the
channel is
busy, the PDK may again set its internal sleep timer for the next expected
superframe and
return to the sleep mode.
[002391 If the PDK finds the channel to be available, the PDK then transmits
its location
tracking response and waits for one additional timeslot for a response from an
RDC. If the
PDK receives a response from an RDC, it then performs the command sent by the
RDC (e.g.,
to switch to the alternate communications channel). If the PDK does not
receive a response
from an RDC, the PDK may again set its internal sleep timer to wake up just
before the next
expected superframe it should respond to and then return to sleep mode.
[00240] As described above with reference to Figure 31, in one or more
embodiments, an
RDC may be located within an electronic game on an electronic gaming floor.
Each game
may have an integrated dual wireless link RDC, such as that described above
with reference
to Figure 9. The RDC may be used for PDK location tracking and PDK
association. There
are various approaches in integrating an RDC into an electronic game or other
equipment
housing. In one approach, shown in Figure 38, the integration of the RDC is
from a physical
perspective; no electrical connections exist between the RDC and the game. In
this
CA 02636167 2008-07-03
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configuration, the RDC and electronic game need not even reside within the
same enclosure;
they coexist as two physically close, but separate, devices. They may not be
connected in any
way other than physical proximity. The purpose of placing them in close
physical proximity
is to allow the RDC to perform proximity detection for any player carrying a
PDK that may
be positioned near the front of the machine. In this configuration, each
device (RDC and
electronic game) may have -separate connections to a central server (or an
external data
concentrator) used to connect both devices to a single wired connection back
to the server. It
is noted that the game may operate autonomously, with the possible exception
of responses to
any commands sent to it by the server. In this case, the RDC may provide both
proximity
detection and association with PDKs.
[00241] Now also referring to Figure 39, it shows an example of a handshake
that may
take place from the time a player carrying a PDK is detected to the time the
game is enabled
for that player. For purposes of clarity, the CRDC is not shown in Figure 39.
The handshake
starts by the PDK detecting a c-beacon. Each time the c-beacon is detected on
the expected
superfrarne and timeslot, the PDK may send out a PDK location tracking
response.
[00242] The RDC near the game detects the response and sends the PDK's
information
back to the central server. The server realizes the user is close to the game
and may send a
command back to the game instructing it to display a message for the player in
an effort to
entice the player to play. In this example, the player may see the message and
sit down at the
game and press a button to commence play. In turn, the game sends a message
back to the
server indicating that the button has been pressed. The server then requests
the RDC to make
a connection with the player's PDK. Upon the next c-beacon, the player's PDK
responds and
the RDC receives the response. The RDC then transmits back to the PDK to
change to
another channel for association mode to begin. It is noted that up until this
time, the PDK
was in tracking mode. The PDK then switches to the altemate channel indicated
by the RDC
and sends out a PDK link request with both the PDK ID and the RDC ID. The RDC
detects
the request and sends back a PDK link grant. The PDK and the RDC then exchange
secure
information to establish trust, prior to establishing a secure link for
validation of the PDK.
The RDC may also lower its RF power and instruct the PDK to lower its RF power
in order to
enforce close proximity. Periodic data exchange may continue to between the
RDC and
PDK.
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[00243] After the secure link is established, the RDC may report back to the
central
server that the link is established between the RDC and PDK. The central
server may then
send a command to the game to display a message, which 'the game then
displays. The player
may see the message on the screen and presses his PDK's button causing it to
transmit this
event over the secure link to the RDC. The RDC relays this information back to
the server.
When the central Server receives the button press message, it can enable the
game so that the
player may begin playing.
[00244] The handshake continues as shown in Figure 40. After the game has been
enabled for the player to play, the server may then send a command to the RDC
to start
polling the player's PDK. The RDC then periodically polls the PDK and may have
returned
the responses of each poll back to the server, as shown in Figure 40.
[00245] Still referring to the example being described with reference to
Figures 39 and
40, the player may continue to play the game for a while, then finishes and
decides to leave.
When the player exits the coverage area of the RDC near the game, the
communications link
is broken: The RDC attempts to poll the PDK, but receives no response. The RDC
continues
a few more times with no response. The RDC then reports back to the central
server that the
link was lost and the PDK is out of range. The central server then sends a
message to the
game to return it to an idle state so that another player can play, then
requests the game to
send back the player's game play information (if not already obtained), which
the server logs.
[00246] As described above with reference to Figures 39 and 40, a central
server may be
the communications medium linking an RDC to a game. It communicates with the
game,
tying the PDK to that game. If either device loses connection to the central
server, game play
may stay enabled.
[00247] Now referring to Figure 41, it shows an electronic game with an
integrated RDC,
internally connected to communicate directly with the game. Thus, all power
and
communication for the RDC may go through the electronic game. In this
configuration, both
the RDC and game reside within the same game enclosure where they jointly
coexist. All
information exchanged between the RDC and Bally Central Server must flow
through the
electronic game's controller and network interface. The purpose of placing
them in the same
enclosure allows the RDC to perform proximity detection for any player
carrying a PDK
57
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WO 2007/081839 PCT/US2007/000349
that may be positioned near the front of the machine.
[002481 At least one difference iri the configuration shown in Figure 41
relative to the
configuration shown in Figure 38 is that the game's intemal controller may act
to reduce the
traffic loading on the back-end network and perform more local verification of
the
communications link between the PDK and the RDC. To illustrate a difference in
interaction
between these two configurations, reference is made to the handshake diagrarri
shown in
Figure 42. More particularly, Figure 42 shows a handshake that may take place
from the time
a player carrying a PDK is detected to the time the game is enabled for that
player. For
purposes of clarity, the CRDC is not shown in Figure 42. The handshake starts
by the PDK
detecting a c-beacon. Each time the c-beacon is detected on the expected
superframe and
timeslot, the PDK sends out a PDK location tracking response. The RDC within
the game
detects the response and sends the PDK information back .to a central server
via the game's
internal controller. The server is made aware that the user is close to the
game and sends a
command back to the game controller instructing the game to, for example, give
the user a
free game along with optionally displaying the user's name. The game then
displays a
message for the player in an effort to entice the player to play. The player
may then see the
message, sit down at the game, and press a button to commence game play. In
turn, the game
controller detects the button press and requests the RDC to make a connection
with the
player's PDK. Upon the next c-beacon, the PDK responds and the RDC receives
the
response. The RDC may then transmit back to the PDK a command to change to an
alternate
channel for association. The player's PDK then switches to the alternate
channel indicated by
the RDC and sends out a PDK link request with both the PDK ID and the RDC ID.
The RDC
detects the request and sends back a PDK link grant. The PDK and the RDC may
then
exchange secure information to establish trust, prior to establishing a secure
link for
validation of the PDK.. The RDC may also lower its RF power and instruct the
PDK to lower
its RF power in order to enforce close proximity. Periodic data exchange may
then continue
between the RDC and PDK.
[00249] After the secure link is established, the RDC reports back to the game
controller
that the link is established between the RDC and PDK. The game may then
display an
instructional message for game play. The player may see the message on the
screen and
presses the player's PDK button, causing the PDK to transmit this event over
the secure link
59
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to the RDC. The RDC may then send this information back to the game
controller. When the
game controller receives the button press message, it can enable the game so
that the player
can begin playing.
[002501 The handshake continues as shown in Figure 43. After the game was
enabled
for the player to play, the game controller sends a command. to the RDC to
start polling the
player's PDK. The RDC then periodically polled his PDK and had the option of
returning the
responses of each poll back to the controller, as shown in Figure 43.
[00251I Returning to the example described above with reference to Figures 42
and 43,
the player may continue to play the game for a while, then finishes and
decides to leave.
1o When the player exits the coverage area of the RDC near the game, the
communications link
is broken. The RDC attempts to poll the PDK, but receives no response. The RDC
may
continue a few more times, with no response. The RDC then reports back to the
game
controller that the link was lost and the PDK is out of range. The game
controller returns
itself to an idle state so that another player can play and indicates back to
the central server
that the PDK is out of range. The server may then request the game to send the
player's game
play information (if not already received), which is then logged.
[00252] As described above with reference to Figures 42 and 43, in one or more
embodiments, the game controller may become more involved in the RDC to PDK
association, thereby potentially reducing the back-end system network's
traffic loading
relative to that experienced with 'the configuration where an RDC is
electrically separate from
the game controller. The game controller may also react faster to the user
walking out of
range and may not require any response from the server in order to maintain
the link. It is
further noted that a broken link between the central server, game controller,
and RDC may
not result in any loss of any interaction between the RDC and the game
controller.
[00253] While the invention has been described with respect to a limited
number of
embodiments, those skilled in the art, having benefit of the above
description, will appreciate
that other embodiments may be devised which do not depart from the scope of
the present
invention as described herein. Accordingly, the scope of the present invention
should be
limited only by the appended claims.
59
