Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
~ 92/17978 PC~r/US92/02552
`~10S380
1 0
USER FEATURES FOR NEXT GENERATION
CORDLESS TELEPHONE NETWORKS
Technical Field
This invention relates generally to the field of portable or
cordless telephones systems and more specifically to the
monitoring of the communicating capability of the transceiver of
these systems.
2S
Backç1ro~nd Art
A portable telephone system, such as the second-
generation digital cordless telephony (CT2), has multiple
transceivers which are located at a call point station or public
base station known as a telepoint. These transceivers allow
persons using portable or wireless telephones to access the
public telephonè network when in range or within a service area.
However, a range of distances up to about 400 feet,
depending on the surroundings, is possible. This distance, while
providing a convenience as to where calls can be placed ~rom
also creates two new problems. Unlike today's NcordedN phone_
.
,
wo 92/17978 2~.Q $~8 ~ PCr/US92/02~
booth where the caller has to actually reach it before a call can be
placed, there is no indication of an in range condition until after
the caller has failed to make a call in the wireless system.
Another problem is created when the caller, who is within
range of the cordless telephone booth, but cannot acquire a dial
tone to obtain an open line, since the transceivers of the base
station can handle only a limited number of simultaneous phone
calls made by different portable telephones~ Because the caller
does not know if one of the transceivers is available or they are
10 fully utilized until the caller attempts to access the transceivers, it
is fnustrating for the caller to find that a transceiver is not available
only after a phone call has been attempted. Even if a "busy"
visual annunciator was available at the telepoint, if a caller is too
far away or not within the line-of-sight of the annunciator, the
15 caller would still not receive any busy indication.
Unlike today's "corded" phone booths, the callers wait in
line and psychologically are prepared to wait, since they can see
their placement in the queue. However, a cordless telepoint user
on the other hand, is not prepared to wait, but is frustrated
20 instead, since there is no indication of a queue line being formed.
Therefore, a need arises for handset or cordless telephone
subscribers to obtain in range and busy information from CT2
base stations before their call attempts fail. Currently, losses of
revenue may occur since the quantity of calls that could not be
2~ made, due to a busy base or telepoint condition is not tracked.
Hence, there is also a need for a means of determining how many
call requests were attempted during a busy hour to justify system
expansion.
30 Summarv of the Invention
Accordingly, it is an advantage of the present invention to
transmit a call point signal for indicating in range condition and /or
the unavailability of a public telephone network from a portable
telephone interconnection device (telepoint) to a wireless phone
3~ due to being "busyn. Additionally, the telepoint can record
whether it has reached its maximum number of interconnections.
: . , ~ .
.: . . - :. :
.
.
~92/17978 o ~3 ~ o Pcr/vsg2/o2552
Briefly, according to the invention, a public telephone
network to portable telephone interconnection device is provided.
At least one transceiver interconnects a plurality of portable
telephones to the public telephone network. A channel monitor
monitors the transceivers to provide information. At least one
information transceiver interconnects the plurality of portable
telephones to and is responsive to the monitor for transmitting the
information to the plurality of portable telephones.
In one aspect of the invention, the availability of portable
telephones to public telephone network interconnections is the
information determined and provided.
In another aspect of the invention, the placement of the
requesting portable telephones in a queue is the information
determined and provided.
In a fur~her aspect of the invention, the available
transceiver or the information transceiver transmits information
representing a calling back of the portable telephones in the
queue.
In another aspect of the invention, the monitor monitors the
transceivers to determine whether the portable telephones are
within a service area of the transceivers.
Brief Description of the Drawinqs
Figure 1 conceptually shows a cordless telephone network
in accordance with the invention.
Figure 2 shows a basic block diagram of a public cordless
telephone base station in accordance with the invention.
Figure 3 shows a block diagram of a cordless telephone in
accordance with ~he invention.
Figure 4 is a system flow-chart in accordance with the
present invention.
- .
... . . .
';. : ' . ~ .. . .
WO 92/17978 2 1 0 S 3 8 0 PCl-/VS92/02~,
DetaTled Descri~tion o~ the Preferred Embodiment
Referring to FIG. 1, a communication system 10 for
providing services to a plurality of subscribers (not shown)
comprises a plurality of public base stations or CT2 call point
stations 20, 22, and 24 and a plurality of wireless mobi!e
subscriber units or cordless telephones (represented by a
handset 12). A telephone system, for example, a public switched
telephone network (PSTN) 16 allows subscribers to communicate
with other telephone users. The present invention can work with
any type of telephone system or network such as a public system
(PSTN) or a private system. Private systems include a key
system, a private branch exchange (PBX), or a private automated
branch exchange (PABX).
Each subscriber can communicate with the PSTN 16 via
the network of public base stations 20, 22, and 24. In this system,
a voice connection is established by RF transmission from the
cordless telephone handset 12 via the public base station or fixed
device 20, 22, or 24 to a telephone set not shown (but accessible
by the public switched telephone network 16).
Referring to Figure 2, a public base station (or wireless
phone booth or telepoint) 20, capable of receiving calls from the
portable telephones 12, in accordance with the invention is
shown in block diagram form. Each of the components of the
wireless phone booth 20 represented by a block is conventional.
A plurality of antennas 32a-n are each coupled to at least one RF
transceiver or CT2 multi-channel radio frequency transceiver 30a-
n for communication between the portable or wireless telephone
handset 12, which includes a corresponding radio frequency
transceiver 50 (see FIG. 3). The base station 20 also includes a
memory 36 for storing information including memory templates
containing information relating to subscribers such as their
address codes or identifications and a controller or channel
monitor 38 (e.g., a conventional microprocessor) for processing
the information received from the transceivers 30a-n and 82
and/or the information stored in the memory 36. A part of the
, ~
- . ; ~ ' ,' ~ .~ .
~ 92/17978 ` PCI`/US92/~2552
210~380
memory 36 may also provide call authentication and verification
statistic functions.
A PSTN interface module 34 provides an interface
between the public telephone network 16 and the transceivers
30a-n via phone lines coupled between the transceivers 30a-n
and the the PSTN interface module 34. The CT2 multi-channel
transceiver activity is monitored by the controller or the channel
usage monitor 38. The channel usage monitor controller 38
determines whether or not the CT2 multi-channel transceiver 30a-
n is utilizing all of its predetermined number of phone lines.
When such a phone line is granted by the controller 38, a dial
tone will also be transmitted to the handset 12 by one of the
transceivers 30a-n.
Given a set number of phone lines, the CT2 call point or
1~ base station 20 can handle only a predetermined number of
interconnections or phones lines for portable or wireless
telephone handsets 12 within its transceiving area or range. As a
result, a portable or wireless telephone 12 attempting to place a
call after the predetermined number of interconnections or phone
lines have been made will not be able to connect to the public
telephone network 16 via a phone line coupled between one of
the available transceivers 30a-n and the the PSTN interface
module 34 as permitted by the controller 38 and a dial tone will
not be received by the handset 12 from the transceiver 30a-n.
To provide more status information, the present invention
provides at least one additional transceiver called an in range
and busy transceiver (IRBT or IRB transceiver) 82 which is
incorporated in the base station 20 for the purpose of
communicating "in range" and "busy status" to those subscriber
handsets 12 that are adapted to receive the information and
correspondingly indicate the information. Along with the
controller 38, the IRBT 82 provides helpful statistics regarding
system traffic which will aid in planning for system expansion.
The same IRBT 82 could also be used for queuing and call back
purposes.
;' . ~ ' :
' ' :
wo 92/1797~ ~z~3~ Pcrtuss2to2~
The IRBT 82 is under the control of the base station`s main
controller 38 and is also connected to the antenna 32n. The main
controller 38 continually updates the IRBT 82 with information on
telephone line availability and/or the frequencies or channels in
5 use. Based on this information the IRBT 82, the channels or
frequencies in use will be neglected during its scan by the IRBT
82. The IRBT 82 continuously scans the remaining free channels
looking for requests for range or line availability requests from the
handset 12.
The data continuously collected by the IRBT base station
controller 38 concerning the quantity of calls that could not be
made due to a base busy condition is also stored in the memory
36. This information can be used to justify upgrades of the base
station for additional phone lines. Especially in heavy traffic
15 areas, additional IRBT's 82 can be added and will therefore be
even more useful in obtaining information for expansion, since a
busy unrecorded base station will never know of additional
attempts that could not be completed.
Referring to FIG. 3, a cordless handset 12 in accordance
20 with the invention is shown. Basically, within the syst.em 10 of
FlGs. 1 and 2, the base station 20, 22, or 24 performs connection
control based upon a request received from the handset 12. The
base station 20, 22 or 24 further transmits data information to the
handset 12. Operating as a means for requesting and
25 subsequently receiving a dial tone for a phone line connection in
the base station 20, the cordless telephone handset (or wireless
mobile subscriber unit) 12 comprises a conventional radio
transceiver 50. As the mastermind of the handset 12, a controller
52 includes memory 53 containing the address or identification of
30 the handset 12, the subscriber unit ID number, and/or other
system operation parameters. A keypad 62 allows the user to
type commands or information requests to the public base station
20 such as dialing a number sequence to request information
a~out range or availability or as conventionally, to request a
35 phone line connection.
. .
. : . .
:
. .. ~ . .
, : ' :
~ 92/17978 ` ` ; PCI`/US92/02552
~ 7 210S38~
The cordless telephone handset 12 further camprises an
audio section 49 connected to an earphone 55 and a microphone
54. A display 70 may provide the user with range or availability
information to determine when the phone line will not be
5 connected to disallow the call. An indicator 40, comprising the
display 70 or the microphone 54, or some other suitable
indication means, is responsive to the information gathered by the
channel monitor controller 38 and transmitted by the IRB
transceiver 82. The indicator may be an annunciator or a light
10 that is observable on the handset 12, a synthesized voice
message provided by the earphone 55, or a message or symbol
displayed on the display 70 of the handset 12.
The user of the portable telephone 12 can determine if the
call will not be connected to the public telephone network 16 by
15 observing the indication means or indicator 40 for representing
phone line unavailability or an out-of-range indication. If no "in
range" message is received, the handset can interpret this
absence as and provide an indication 40 of "out-of-range".
If the channel monitor or controller 38 of the base 20
20 determines that the maximum number of phone !ines are currently
being utilized, the indicator 40 at the handset 12 will indicate that
the call point is busy by lighting a busy sign or otherwise
representing such a message. Based on past statistics, the user
may receive a message about the waiting time from the IRBT 82.
25 In addition, the IRBT 82 may place the user in queue and call him
or her back when a line is available. Depending on the
circumstances then, the user either waits for the indicator 40 to
indicate that a channel is available, waits for a call back or travels
to another CT2 call point station. While the preferred
30 embodiment essentially utilizes a "busy" indication, an "available"
indication could also be utilized for this purpose.
On the other hand, if the maximum number of portable
telephone line connections are not being utilized and the handset
12 is in range, a dial tone will be received or alternately, an
35 available indicator may be turned on.
' ~
' . ' ' `'`' ~ ' '
, .` . : :
.
WO 92/17978 2 ~ O S 3 8 0 ` PCI/US92/02~
FIG. 4 shows a flowchart of the system operation in
accordance with the present invention. An initiating block or step
84 is the starting point of the routine for monitoring interconnect
availability and controlling the indicator 40 at the handset 12 by
information transmitted by the IRB transceiver 82. In normal
operation, a key press sequence (84) is initiated by the handset
subscriber to attempt to obtain a link or phone line access via a
keypad 62. In step 88, the base channel monitor controller 38,
responsive to the CT2 multi-channel radio frequency transceiver
30a-n, determines whether the transceiver 30a-n is fully utilizing
its predetermined number of phone lines available for
interconnecting the po~table telephones 12 to the public
telephone network 16.
If the handset 12 is in range and the base 20 is not busy,
and hence a line is available, the user or subscriber receives a
dial tone and a call is connected in step 92 after the "yes" path is
taken from the "in range" decision block 86 and the "no" path
branch is taken from the "base busy" decision block 88. Hence,
when a phone line is available, the subscriber would establish
the link with one of the base transceivers 30a-n and the phone
call would be connected (92) as in an normal CT2 operation.
Since the CT2 multi-channel transceiver 30a-n has not exceeded
its predetermined number of phone line interconnections, the
indicator 40 at the handset 12 need not be turned ~On".
When phone lines are available, the IRB transceiver 82
need only respond to requests for in range information, since the
handset 12 can automatically obtain a link as in normal operation.
To determine if the subscriber is within range of an IRBT
equipped base station 20, a unique key press sequence via the
keypad 62 or some other suitable method may be initiated. This
unique key press sequence can also be automatically initiated by
the hand set 12 for continuous monitoring of the "in range"
condition, if the unit was so pre-programmed in the controller 52.
Thus, a handset 12 can request in range information at any time
and will not tie up a phone line since the IRBT 82 is not connected
to the PSTN 16. Any available transceiver 30a-n not currently
~ . ., , ~ . . -.
. .
-'. ., '-: .. :. . -
,
. . .
. .
.
~ 92/17978 PCT/US92/025~2
... .
9 2io~3s~
connecting another subscriber's handset to a phone line aside
from the IRBT 82 could also momentarily grant a link (98) and
provide the handset 12 with the message "in range" or a
representation thereof as for the busy indication.
- Alternately, no "in range" indication need be given since
the phone line could then be connected and a dial tone provided
to indicate "link established". This ability of the handset 12 to
momentarily obtain a link before a phone line connection is made
will allow the subscriber to determine range status with an IRBT
1 0 equipped base station by the use of the "in range" indication.
Since the base is not busy, as determined by the decision
block 88, but the call is not connected as evidenced by the lack of
a dial tone or an "in range" transmission, the out-of-range
indication of step 94 will be provided by the handset 12 after
1 5 taking the "no" branch from the "in range" decision block 86.
It the CT2 multi-channel transceiver 30a-n is fully utilizing
its predetermined number of phone lines, the indicator 40 is
turned rOn" at step 108 upon a message sent to the handset 12 by
the IRB transceiver 82 in step 104. Since all the phone lines are
busy as determined by the controller 38 in decision block 88, and
therefore all base transceivers 30a-n are in use, the IRBT 82 will
establish a link with the subscriber (98) and transmit (104) the
message ~all lines are busy" to the handset 12. In this case
where the base is busy, and the handset is in range, satisfying
both "yes" branches from the decision blocks 86 and 88
respectively, the handset 12 is connected to the IRBT 82 in step
96 by establishing a link between the handset 12 and the IRBT 82
in step 98. Additionally, the link attempt is logged by the base
controller 38 in step 102. Meanwhile, a base busy message is
transmitted by the IRBT 82 to the handset 12 in step 104.
After the message is sent and received, the link is dropped
from the IRBT 82 to the handset 12 in step 106 if the queuing and
call back functions are not available at the base (109).
Meanwhile, the handset 12 will receive the message, decode it,
- 35 and indicate the information (108) of some kind of base busy
representation via many possible paths 40, either though a
';, ~ . . '' .' . ~'
. ~ . .. .
WO 92/~7978 PCI`/US92/02
2io~3so
synthesized message outputed by the earphone 55 or visually
displayed by the display 70. Optionally, an auto retry procedure
may also be initiated in step 108.
Alternately, if queuing and call back are available at the
base as determined by decision block 109), the base controller
38 may place the address of the handset 12 in a queue forthe
handset 12 to be called back when a phone line is available in
step 11 2. The rest of the flow chart describes a signalling
protocol to eliminate the uncertainty of the availability of a
1 0 wireless phone booth by providing the subscribers with queuing
information. A predetermined time interval between calls is used
to obtain all queuing information. Since the traffic statistics are
available at the base station controller 38 and based on past
performance, the handset subscribers can receive an average
1 5 waiting time before their call will be processed, as calculated by
the controller 38 and transmitted to the handset 12 via the IRBT
82. The user gets a number in queue and an average weight
time calculated by the controller 38 in that location as transmitted
by the IRBT 82 to the handset 12 in step 11 ~. Hence, if the
average waiting time is acceptable to the user, they remain at that
location, if not, they try to find another IRBT equipped base
station to provide them with similar status information or wait
without knowing at non-lRBT equipped base stations.
In step 11 6, the handset 12 looks for its address code as
transmitted by the IRBT or by one of the available transceivers
30a-n for a call back. The handset 12 returns to step 11 4 if the
base 20 has not processed the last call as determined by a
decision block 11 8 in the handset 12 since none of the
transceivers 30a-n or 82 has responded yet.
On the other hand, if the base 20 has processed the last
call, as determined by the decision block 118, one of the
available transceivers 30a-n sends the user address (which was
queued on a first in first out (FIFO) basis) and dial tone after
linking with ~he handset 12 in step 122 and dropping the link with
the IRBT 82.
~ 92~17978 PCT/US92/02552
0~380
In summary, the call point stations 20 are generally in
public areas and have a substantially limited radio frequency
coverage area. However, many people may be standing within
the coverage area, some having and using portable telephones
5 and others not. Thus, if not for this ir vention, the user would have
no reasonable method of determining who is and who is not
using ths telephone system within the coverage area, and if the
full capacity of the station is utilized. This invention thus provides
the user with a convenient and accurate indication of the
10 availability of the telephone system within the area in which it may
be used.
What is claimed is:
.
, .
