Note: Descriptions are shown in the official language in which they were submitted.
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A SUBSCRIBER UNIT FO~ USE IN A
MULTIPLE ACCESS COMMUNICATION S'~STEM
Backqround of the Invention
The present invention relates to wireless communication systems.
More specifically, it relates to the subscriber units used in mobile wireless
communication systems.
Current efforts in wireless communications, particularly in the segment
of wireless communications referred to as Specialized Mobile Radio (SMR),
have the goal of providing greater functionality to the SMR user, commonly
known as a subscriber. These efforts have been limited by problems in the
present SMR equipment. One equipment area where severe limitations exist
is in the unit the subscriber uses to communicate, known as the subscriber
unit.
The limitations include a problematic electronic architectural design
that hinders the capabilities of the subscriber unit. As a result of this
limitation, the subscriber units are unable to efficiently process the signals
they communicate, including voice and data signals. Further, as a result of
the problematic architecture, the subscriber units are unable to efficiently
handle peripheral devices which may be necessary to efficiently process the
communication signals received by the subscriber unit.
Current subscriber units are also limited in the features that they
provide to their users, thereby causing inefficient use of communications
resources. Many of these limitations exist in dispatch communication,
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wherein businesses that have field employees -- employees working outside
the office environment -- communicate with one or more of those employees
at a time. One problem commonly encountered is that the field employees
often must leave their vehicles (where the subscriber units are mounted) in
order to perform their jobs and thus are not always able to hear the
dispatched information on their radio terminals. If the field employee is away
from the vehicle when a message is dispatched, the employee wiil miss the
dispatched message. Depending on the importance of the message, this can
lead to unfortunate results. This is but one example of the problems with
current subscriber units -- there are many others.
In view of these and other limitations, systems and methods for more
efficiently processing dispatched communications, therefore, are needed.
Summarv of the Invention
In accordance with the present invention, a new subscriber unit
architecture is utilized. The mobile subscriber unit of the present invention
includes two pieces of equipment, a radio unit and a subscriber terminal. In
accordance with a preferred embodiment of the present invention, the radio
unit is housed in the trunk of an automobile while the subscriber terminal is
housed in the passenger compartment of the automobile.
The radio unit includes a receiver, a transmitter, an inputloutput
terminal, and processing means. The radio unit processor means processes
the received and transmitted communication signals to provide
communication services information through the radio unit input!output
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terminal. The subscriber terminal includes an input/output terminal for
communicating with the radio unit input/output terminai, a display for
displaying information to the subscriber, a keypad through which the
subscriber can enter information and processor means. The subscriber
terminal processor means controls the display and the keypad. It also
processes the communication services information supplied by the radio unit.
It is also preferred to provide a second input/output terminal in the subscriberunit which is controlled by the processor means in the subscriber unit.
Peripheral devices such as magnetic swipe devices, printers, bar code
scanners and serial keyboards can be connected to this second input/output
device and operated under the control of the subscriber unit processor
means.
In accordance with another aspect of the present invention, dispatch
information is transmitted over a wireless communication system and is
processed in a subscriber unit. The subscriber unit stores all dispatch
activity in a memory. Then, when requested by the user of the subscriber
unit, the memory is accessed and a list of information related to the dispatch
communications is displayed along with the time of occurrence for each
dispatch communication. In accordance with a further aspect of the present
invention, the dispatch information can be used to enable the user of the
subscriber unit to call the entity that generated the dispatch communication.
To call that entity, the user selects one of the displayed dispatch activities
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by cursoring up and down the iist and then selecting the appropriate key.
The subscriber unit then causes a call to be made to the source of the
selected dispatch communication.
As part of a dispatch scanning function performed by the subscriber
unit, the subscriber unit stores a list of one or more groups to which the
subscriber is assigned to and, when a dispatch communication is received,
the subscriber unit determines the group to which the dispatch is directed
and informs the subscriber of the group. In accordance with yet another
aspect of the present invention, this dispatch scanning function is modified
to perform priority scanning, scan nuisance deiete and time scan disable.
In priority scanning, a priority level is assigned to each group and is
stored by the subscriber unit in the list of assigned groups. Whenever a
dispatch communication is received, the subscriber unit determines the
group to which the dispatch is directed and then accesses the table of
assigned groups and group priority levels. If there is an existing dispatch
communication being processed when a new dispatch communication is
received which is directed to one of the subscriber's groups, the subscriber
unit compares the priority level of the existing dispatch communication and
the priority level of the newly received dispatch communication and enables
the reception of the dispatch communication with the highest priority level.
In scan nuisance delete, during times when there is excess and
unwanted dispatch communication traffic to a group to which the subscriber
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unit is assigned, the subscriber can select that group and delete it from the
list which the subscriber unit maintains as part of the scanning function.
The subscriber unit then does not scan for dispatches to that group, thereby
eliminating the nuisance traffic.
In time scan disable, the subscriber can program the subscriber unit to
stop scanning the list of groups to which the subscriber unit is assigned and
then, after a selected period of time, enable the subscriber unit to
automatically start the scanning process again.
The invention will now be described in connection with certain
illustrated embodiments; however, it should be clear to those skilled in the
art that various modifications, additions and subtractions can be made
without departing from the spirit and scope of the claims.
Description of the Drawings
FIG. 1 illustrates a wireless communication system having a base
station, a dispatch station and a plurality of subscriber units;
FIG. 2 illustrates the air interface utilized by the base station, the
dispatch station and the subscriber units to communicate;
FIG. 3 shows a block diagram of the subscriber unit, including the
radio unit and the subscriber terminal;
FIG. 4 illustrates an external view of the subscriber terminal;
FIG. 5 illustrates the circuitry of the subscriber terminal;
FIG. 6 illustrates the circuitry of the radio unit;
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FIGS. 7 and 10 illustrate various screens shown on the display of the
subscriber terminal during the dispatch mode;
FIG. 8 illustrates the distribution of dispatch group information to
subscriber units;
FIG. 9 illustrates the steps taken by the subscriber unit upon reception
of a dispatch and the steps taken to display the dispatch history;
FIG. 11 illustrates steps taken by the subscriber uriit in implementing
the last dispatch function;
FIG. 12 illustrates the steps taken by the subscriber unit to perform
1 0 priority scanning;
FlG. 13 illustrates the steps taken by the subscriber unit to perform
scan nuisance deletion; and
FIG. 14 illustrates the steps taken by the subscriber unit to perform
time scan deletion.
DescriPtion of the Preferred Embodiment
Referring to FIG. 1, a communication system 1 is illustrated. The
system 1 includes a base station 2, a dispatch station 4 and a plurality of
subscriber units 6. The communication system 1 may be a frequency
hopping system which is divided into sectors 8 to 10 wherein sets of
frequencies are reused in each sector to provide wireless communications.
Note, however, that the present invention may be used on other types of
communication systems, including TDMA systems, CDMA systems and even
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analog based systems.
The base station 2 includes the communication equipment necessary
to provide the multiple access communications for the plurality of
subscribers units 6 and for the dispatch station 4. The base station 2 also
includes the communication equipment needed to provide communications
through the Public Switched Telephone Network (PSTN).
The dispatch station 4 includes equipment necessary to dispatch
communications from the dispatch station 4 to a number of subscriber units
6, commonly referred to as point-to-multipoint communications, and it also
includes equipment that provides point-to-point communications. The
subscriber units 6 generally consist of mobile or portable equipment
necessary to transmit, receive and process communication signals.
Referring to FIG. 2, the communication links between the base station
2, the dispatch station 4 and the subscriber units 6 -- referred to as the
common air interface -- are illustrated. The communication channels in FIG.
2 include a plurality of traffic channels (TCHs), at least one control channel
(CCH) and at least one access channel (ACH). In the communication system
1 of FIG. 1, all of these channels are present in each sector 8 to 10. The
TCHs operate in the uplink (transmissions from subscriber units 6 to the base
station 2) and in the downlink (transmissions from the base station 2 to the
subscriber units 6). The CCH and the ACH, however, operate only in one
direction -- the CCH in the downlink and the ACH in the uplink.
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In the illustrated embodiment of FIGS. 1 and 2, ten 25 kHz frequency
channels are used to define ten uplink channels and ten 25 kHz frequency
channels are used to define ten downlink channels. In each sector 8 to 10,
nine of the frequency channels are used to implement nine uplink TCHs and
nine of the frequency channels are used to implement nine downlink TCHs.
In each sector, the remaining frequency channels are used to transmit one
ACH and one CCH. Voice information, data information and inband
overhead control signals between the base station 2 and the subscriber units
6 are transmitted over the TCHs, preferably using frequency hopping and
time hopping communication methodology - - but any communication
method and any air interface may be used. Timing and control signals from
the base station 2 to the subscriber unit 6 are transmitted on the CCH.
Status and operational requests from the subscriber unit 6 to the base
station 2 are transmitted on the ACH. The common air interface of FIG. 2 is
also used in communications between the base station 2 and the dispatch
station 4.
Now that the communication system in which the subscriber unit 6 of
the present invention operates has been described, the subscriber unit 6 will
be described. Referring to FIG. 3, the subscriber unit 6 of the present
invention is divided into two pieces of equipment, a radio unit 12 and a
subscriber terminal 14. In general, the radio unit 12 transmits and receives
communication signals to and from the base station 2, the dispatch station 4
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or other subscriber units 6 through a pair of antennas 15 and 16 under the
control of the subsc,iber terminal 14.
The radio unit 12, as ~vill be seen in greater detail in later discussions
and figures, provides the processing power needed to transmit and receive
by performing essential communication processes. For example, the radio
unit 12 performs the needed signal processing on transmit and receive
signals, such as voice coding, error correction encoding, interleaving, Viterbi
decoding, frequency hopping, time hopping, automatic gain control,
automatic frequency modulation, diversity reception processing and
modulation. The radio unit 12 aiso determines whether communications are
voice communications, data communications or dispatch communications as
well as various attributes concerning these communicationtypesand uses
this information to generate information about the communication services
being provided. T his list will vary from communication system to
communication system, however, the architecture of the present invention
requires that the processing necessary to the communication system being
used be included in the radio unit 12.
The radio unit 12, therefore processes the received and transmitted
communication signals to provide communication services information. This
information is provided to the subscriber terminal 14 through the interfaces
17 and 18. The subscriber unit 14 provides a keypad and display interface
to a subscriber and r-ceives the communication services information from
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the radio unit 12. The subscriber unit 14 also has a processor that controls
the display and the keypad and also processes the communication services
information provided by the radio unit 12.
The architecture of FIG. 3 is a client-server architecture wherein the
subscriber terminal 14 is the client and the radio unit 12 is the server that
serves the communication needs of the client the subscriber terminal 14. In
the architecture of FIG. 3, the functions which provide an interface between
communication services (voice transmit, voice receive, dispatch, data
transfer, etc.) and the subscriber are performed by the subscriber terminal 14
while the functions which are necessary to interface to the communication
system 1 to provide communication services are performed by the radio unit
12. Then when the subscriber requires the use of a communication service,
the subscriber terminal 14 requests access to that service through the radio
unit 12 and it is provided.
FIGS. 4 to 6 illustrate various aspects of the subscriber unit 6. In
FIG. 4, an external view of a subscriber terminal 14, which is preferably
positioned next to the subscriber in the passenger compartment of a vehicle,
is illustrated. The subscriber terminal 14 includes a display 24, a keypad 26
and a handset 28. The keypad 26 includes five keys 30 to 34, commonly
referred to as soft keys, whose function is defined by the features shown on
the bottom of the display 24. The keypad 26 also includes a plurality of
keys 36 to 43 having a variety of functions. Each of the keys 36 to 41 is
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positioned ne~ct to a LED display 44 which is illuminated when the function
associated with the key is enabled. The handset 28 includes a numeric
keypad and the keys necessary to start and end a communication session.
The handset 28 aiso has the traditional push-to-talk button found on many
radio units.
In FIGS. 5 and 6, the processing circuitry of the subscriber terminal 14
and the radio unit 12, respectively, is illustrated. Referring to FIG. 5, the
subscriber terminal 14 includes a microprocessor 50, an oscillator circuit 52,
a power supply circuit 54, a serial interface circuit 56, a display driver circuit
58, a memory circuit 60, a keyboard interface circuit 62, an l/0 decoder
circuit 64, a LED driver 66 and an interface circuit 68. The subscriber
terminal 14 can also include a real time ciock 70, however, in a preferred
embodiment, the base station 2 distributes real time clock information during
its transmission to each of the subscriber units 6. In this preferred
embodiment, the microprocessor 50 extracts the real time clock information
from signals transmitted by the base station 2 and stores it in the memory
circuit 60. This information is combined with timing information generated
by the oscillator circuit 52 to provide the subscriber terminal 14 with real
time clock information. If the base station 2 distributed real time clock
information is utilized, then the real time clock 70, its back up power source,
the battery 72 and the battery management circuit 72 and 74 in the power
supply circuit 54, can be eliminated.
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The memory circuit 60 includes a decoder circuit 76, an address latch
78, a boot ROM 80, a flash memory 82 and a static RAM 84. The boot
ROM 80 stores the code necessary to initialize the microprocessor 50 and
the circuitry of the subscriber terminal 14 as well as code necessary to
download future software versions for the subscriber terminal 14. The flash
memory 82 is non-volatile re-writable memory which is utilized to store
information which must be maintained even during a loss of power. The
static RAM 84 is utilized as a working memory as needed.
The display driver circuit 58 includes the LCD display 24, a power
supply 86, a LCD controller 88, a memory circuit 90 and an address
controller 92. The display driver circuit 58 is accessed by the
microcontroller 50 via the l/O decoder 64. The information to be displayed
is downloaded from the microprocessor 50 to the memory circuit 90. The
display of the information on the display 24 is then controlled in a
conventional manner by the LCD controller 88.
The microprocessor 50 is responsive to the selection of the keys 30 to
34 and 36 to 43, as well as to the selection of the keys on the handset 28.
When the keys are selected, selection signals are processed through the
keyboard interface circuit 62 to the microprocessor 50. The microprocessor
50 also controls the LEDs 44 through the LED driver circuit 66. The RS-232
interface 94 provides communications between the subscriber terminal 14
and external devices, such as notebook computers, magnetic swipe devices
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used to read magnetic strips, printers, bar code readers and serial keyboards.
The RS-485 interface 96 and the interface circuitry 68 provides
communications between the subscriber terminal 14 and the receiver and
transmitter circuitry of the radio unit 12 (shown in FIG. 6).
In FIG. 6, the circuitry of the radio unit 12 is illustrated. The radio unit
12 includes antennas 102 and 104, a radio board 106, a baseband unit 108,
a service board 110, and a GPS interface 111. The radio unit circuitry
illustrated in FIG. 6, except the antennas 102 and 104, in a preferred
embodiment, is housed separately from the subscriber terminal 14, for
example, inside the trunk of an automobile. The antennas 102 and 104 are
preferably mounted externally on the automobile.
The radio board 106 includes transmitter and receiver circuitry. More
particularly, it includes a transmitter 112, two receiver channels 114 and
116, a duplexer 118, a frequency synthesizer 120, gain and frequency
control circuitry 122 and transmitter gain control circuitry 124. As
previously describer, the circuitry of the radio board 106 provides
communication via frequency hopping, that is, a communication signal is
transmitted and received by hopping the signal over several different
frequency channels.
The radio board 106 is interfaced with the baseband unit 108. The
baseband unit 108 includes a modem 126, a controller 128, a voice
processing package 130 and an interface circuit 132 to the subscriber
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terminal's 14 circuitry. This baseband unit 108 receives the signals to be
transmitted to the base station 2 from the subscriber terminal 14 and sends
the signals to the transmitter 1 12 in the radio board 106 for transmission.
This baseband unit 108 also receives the signals that the radio board 106
receives from the base station 2, performs some processing on the received
signals and sends them to the subscriber terminal 14 through the interface
1 32.
The subscriber terminal 14 has several operational modes, one of
which is the dispatch mode. When a subscriber seiects the DISP KEY 41 on
the subscriber terminal 14, the microprocessor 50 causes the subscriber
terminal 14 to enter the dispatch mode, thereby allowing the subscriber to
view information concerning the dispatch communications on the display 24.
Upon entering the dispatch mode, the microprocessor 50 preferably causes
the screen shown in FIG. 7 to be displayed on the display 24 . The screen
preferably has at least seven sequentially numbered lines. The second line
of the display 24 displays the word "DISPATCH", indicating that the
subscriber terminal 14 is in the dispatch operational mode.
The subscriber unit 6 of the present invention allows subscribers to be
divided into groups and, if desired, into subgroups as the dispatcher desires.
For example, all subscribers that respond to the dispatch station 4 could be
grouped according to their job function and subgrouped according to their
regionai responsibilities. In this example, if the dispatcher is communicating
-
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with sales, service and delivery personnel, the dispatcher could assign all
sales personnel to a first group, all service personnel to a second group and
- all delivery personnel in a third group. Then, calls which only concern sales
personnel can be directed to the first group and so on.
Referring-to FiG. 8, the process of distributing the group and subgroup
information to the subscriber units 6 is illustrated. In step 200, the grouping
and, if desired, the subgrouping desired by the dispatcher is transmitted from
the dispatch station 4 to the base station 2 over a TCH. The base station 2
updates a subscriber database that it maintains and then, in step 202,
transmits the group and subgroup information to all of the subscriber units 6
over a CCH. The group and subgroup transmitted by the base station 2 to
the subscriber unit 6 are preferably stored in the radio unit 12 in memory in
the controller 128 circuitry in step 204. It is possible for the subscriber to
be assigned to multiple groups or multiple subgroups, in which case each of
the assigned groups is stored in the controller 128. It is further preferred
that the dispatcher 4 be able to modify the assigned groups and subgroups
at any time by the method of FIG. 8. Whenever the grouping information is
transmitted, the controller 128 will receive this transmitted information and
store a new grouping and sub-grouping in its memory upon receipt.
When a subscriber belongs to more than one group, the subscriber
can cause the subscriber terminal 14 and the radio unit 12 to enter the scan
mode. The controller 128 in the radio unit 12 stores a list of the groups that
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a subscriber is assigned to. When in the scan mode, the controller 128
compares the group that a dispatch communication is directed to with the
groups in the controller's 128 list. If there is a match, then the controller
enables reception of that dispatch. If the group that the dispatch is directed
to is not on the controller's 128 list, then the controller 128 does not enable
reception of the dispatch.
Information concerning the dispatch group and subgroup that a
dispatch transmission is directed to is displayed on the third and sixth lines
of the display 24 shown in FIG. 7. In FIG. 7, the "12a" (or just "12" if
subgroup information is not being used) on the third line indicates the active
group and subgroup of the subscriber unit 16. The "12" indicates the group
and the "a" indicates the subgroup. The active group is the group which the
subscriber can both hear and transmit to in the dispatch mode. The "3c" on
the sixth line, just above the label LAST, indicates the last group and
subgroup on which there was a dispatch call. The "5a" on the sixth line,
just above the label PICK, indicates the group and subgroup to which an
incoming dispatch is directed.
The items displayed on the seventh line of the display of FIG. 7 define
the functions of the soft keys 30 to 34. In the dispatch mode, as shown in
FIG. 7, the soft keys are defined as follows: the first soft key 30 (labeled
"SCAN") implements the previously discussed scanning function, the second
soft key 31 (labeled "PICK"), when selected, allows the subscriber to change
16
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the active group as displayed on the third line of the display to the group
displayed just above the PICK label (5a in FIG. 7), the third soft key 32
- (labeled "1 T0 1") implements a function which is not relevant to this
invention, the fourth soft key 33 (labeled "HIST") implements a dispatch
communication processing function in accordance with one aspect of the
present invention and the fifth soft key 34 (labeled "LAST") implements
another dispatch communication processing function in accordance with
another aspect of the present invention.
Before further describing the functions performed when the HIST and
LAST soft keys are selected by the subscriber, some of the background
processing performed by the subscriber terminal 14 and the radio unit 12 will
be described. FIG. 9 illustrates some of the steps taken by the radio unit 12
and the subscriber terminal 14 each time a communication is received. In
step 300, the radio terminal 12 determines whether the transmission is a
dispatch communication. To allow the radio terminal 12 to perform step
300, the base station 2 adds control bits to transmitted communication
signals on the CCH that match a predetermined sequence when the
communication is a dispatch communication. The controller 128 processes
each communication signal received by the radio unit 12 to determine the
status of the control bits added to the communication signal by the base
station 2. The controller 128 compares these control bits to the
predetermined sequence which is stored in the controller 128 memory to
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determine whether the received communication signal is a dispatch
communication .
If the communication is not a dispatch communication, then the
controller 128 exits the processing routine of FIG. 9 to perform other tasks
on the receive communication signals. On the other hand, if the
transmission is a dispatched communication, then, in step 302, the controller
128 accesses the control information in the communication signal to
determine the group and subgroup (or groups and subgroups) that the
dispatch communication is directed to. Then in step 304, the controller 128
accesses its memory to determine which groups and/or which subgroups the
subscriber is allowed access to and compares this to the information
contained in the dispatch communication. In essence the controller 128
determines whether the base station 2 has indicated that the subscriber
belongs to the group.
If the subscriber is not permitted access to the dispatch, then the
controller 128 exits this process to perform other tasks. If the subscriber is
permitted access to the dispatch communication, then the controller 128
checks to see if the scan function is enabled or if the group is the active
group. If either the scan function is enable or the group is the active group,
the controller 128, in step 306, causes the dispatch communication signal to
be sent from the radio unit 12 to the subscriber terminal 14. Otherwise, this
process is exited.
18
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In step 308, in the subscriber terminal 14, the microprocessor 50
scans the static RAM 84 which stores various information relating to the
past dispatch communications received by the subscriber terminal 14 which
have been directed to a group and/or a sub-group that the subscriber has
been assigned to. The information stored includes the group and subgroup
of the dispatch communication as well as the time of the dispatch
communication. The microprocessor 50 determines whether there has been
a dispatch communication directed to the same group as the present
dispatch communication within a predetermined time period, preferably
within the last minute. If the microprocessor 50 determines that there has
been a dispatch communication directed to the group within the last minute,
the microprocessor 50 exits this routine. If, however, there has been no
dispatch sent to this group within the last minute, the microprocessor 50
continues to step 310 to process the dispatch communication. The purpose
of step 308 is to prevent rapidly repeated dispatch communications within a
group from being stored and displayed to the subscriber thus overwhelming
the history function.
In step 310, the dispatch communication is time tagged by the
microprocessor 50. The microprocessor 50 can time tag the dispatch either
by accessing the real time clock 70 or by utilizing real time clock information
that is distributed by the base station 10. After the time tagging, in step
312, the microprocessor 50 stores information associated with the dispatch
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communicat,on in the static RAM ~4 The stored information nc!udes the
group, subgroups and the time tag associated with the dispatch
communication .
In accordance with the present invention, the subscriber can access
the stored information concerning dispatch communications by selecting the
fourth soft key 33 ~hich is labeled "HIST" in the dispatch op~r2tional mode.
When the HIST key is selected and the subscriber terminal 1~ is in the
dispatch operational mode, the microprocessor 50 preferably causes the
subscriber terminal 14 to implement a function whereby a history of
information concerning or relating to the dispatch communications is
displayed to the subscriber. When the HIST soft key 33 is selected, the
microprocessor 50 causes the screen illustrated in FIG. 10 to be shown on
the display 24. The second line of the display of F~.10, "DISP: CALL
HISTORY", indicates that the subscriber terminal 14 is in the history mode.
Then, on lines 4 to 6, information relating to the last three dispatch
communications is displayed. The displayed information includes the group
to which each dispatch communication was directed as well as the time that
the dispatch communication was received. Also, the subgroup can be
displayed. In a preferred embodiment, the subscriber can access the last ten
dispatch communications that have information stored in memory by usins
the cursor up and cursor down keys 42 and 43 to cause the microprocessor
50 to display additional items from the lists of information that do not fit
2c
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onto the display 24
The microprocessor 50 causes this information to be displayed by
accessing the static RAM 84, retrieving the listing of stored information
relating to past dispatch communications, including the associated group and
time tags, and sending the information to the display 24 through the display
driver circuit 58. Referring to FIG. 10, it can be seen that the subscriber can
determine that the last dispatch communications received by the subscriber
unit 16 were directed to a variety of groups at a variety of times. In
particular, in this example, the display indicates to the subscriber that
dispatch communications were sent to Group 3 at 1 1:14 a.m., to Group 9
at 10:58 a.m. and to the Sales Group at 9:12 a.m.
The arrows on iine 4 of FIG. 10 indicate that the user of the radio
terminal 22 can scroll up and down the displayed listing of dispatch
information by using the keys 43 and 42, respectively. The subscriber
terminal 14 of the present invention also enables the subscriber to make a
call to the source of any of the dispatch communications. This is
accomplished by scrolling to the line where information relating to the
desired dispatch is displayed and then pressing a Push-to-Talk tPTT) button
on the subscriber unit 16, which is located on the handset 28 of the radio
terminal. The selection of the PTT button is recognized by the
microprocessor 50 which then causes a main screen to be displayed as well
as causing the transmission to occur, as described in the following. Upon
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recognition of the selection of the PTT button, the microprocessor 50
determines which group the subscriber wishes to communicate with by
accessing the memory 84 to see which listed dispatch communication the
subscriber has selected. This information is passed to the radio unit 12
where the controller 128 formats a communication signal to be directed to
the dispatch group which the subscriber selected. Communication signals
are then sent by the transmitter 1 12.
In accordance with another aspect of the present invention, the
subscriber can easily change the active group of the subscriber unit--
displayed on the third line of the display 24 -- to the last group -- the group
that was just previously active on the subscriber terminal 14 which is
dispiayed just above the LAST softkey -- by selecting the fifth soft key 34
which is labeled "LAST" while in the dispatch operational mode. The last
group then becomes what was the active group. As an example, in FIG. 7,
1 2a is the active group and 3c is the last group. If a subscriber selects the
LAST softkey, 3c becomes the active group and 1 2a becomes the last
group .
Referring to FIG. 11, This function is accomplished in the subscriber
terminal 14 by the microprocessor 50. The microprocessor 50 maintains the
active group and the last group in memory 84. The microprocessor 50, in
step 350, senses the selection of the LAST softkey and then, in step 352,
causes the active group and the last active group stored in the memory 84
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to be toggled. The microprocessor 50 also causes the groups shown in the
display 24 to be toggled. This allows a subscriber to quickiy respond to a
dispatch communication from another group.
Referring to FIG. 11, steps 354 to 364 illustrate the other steps
performed by the subscriber terminal 14 in implementing the last dispatch
function. In step 354, the microprocessor 50 determines when a dispatch is
received. When a dispatch is received, in step 356, the microprocessor 50
determines whether the PICK softkey is selected. If the PICK softkey is not
selected, the microprocessor 50 causes the group to which the incoming
dispatch was directed to become the last group, but the active group is not
changed. As an example, if the active group was 9, the last group was 6
and the group to which the incoming dispatch was directed was 3, the last
group would be changed to 3, but the active group would remain 9 if the
PICK softkey is not selected.
If the PICK softkey is selected, then in step 360, the microprocessor
50 changes the active group to the group to which the incoming dispatch is
directed and changes the last group to what was the active group. As an
example, if the active group was 9, the last group was 6 and the group to
which the incoming dispatch was directed was 3, then the last group would
be changed to 9 and the active group would be changed to 3.
If a new group is manually selected by a subscriber using keys on the
handset 28, the microprocessor 50 senses the selection in step 362. Then
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in step 364, the microprocessor 50 causes the active group to be changed
to the manually selected group and causes the last group to be changed to
the previously active group. As an example, if the active group was 9, the
Iast group was 6 and the manually selected group was 4, then the active
group would be 4 and the iast group would be 9. In an alternative
embodiment, in step 364, the microprocessor 50 changes the active group
to the manuaily selected group but does not change the last grGup. In the
above example, the active group would again be changed to 4 but the last
group would remain 6.
Referring now to FIG. 12, the steps performed by the controller 128 in
the radio unit 12 to implement the priority scan function are illustrated. In
step 40~:), the controller 128 determines whether a received signal is a
dispatch communications. If it is not, the controller 128 performs other
functions. If the received signal is a dispatch communication, then the
controller 128 determires in step 402 the group to which the disp~l-;h communication is
directed by accessing the control information associated with the
communication .
Then in step 404, the controller 128 accesses its memory to
determine whether the subscriber unit 6 belongs to the group to which the
dispatch communication is directed. Recall that this information is
transmitted by a dispatch station 4 through the base station 2 to the
subscriber terminal 14. If the subscriber unit 6 finds that it does not belong
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to the group, then the controller 128 goes on to perform other functions.
On the other hand, if the subscriber unit 6 finds that it does belong to the
group, then the controller 128 checks to see if the scan function is enabled.
Then, if scan is enabled, in step 406, determines whether there is a prior
dispatch communication being processed. If there is no prior dispatch
communication being processed, then the controller 128 goes on to perform
other functions, such as processing the current dispatch communication. If
there is a prior dispatch communication being processed, then the controller
128 determines whether the subscriber has selected priority scan or not.
The subscriber selects priority scan from the subscriber terminal 14 by
selecting the SETUP button 39 on the keypad 26. During the setup routine,
the subscriber will be given the option of enabling or disabling priority scan.
The subscriber terminal 14 transmits control signals to the radio unit 12 that
indicate the status of priority scan which are stored in the memory of the
radio unit 12. If priority scan is enabled, as part of the setup, the subscriberwill be able to assign a priority level to each group to which he is assigned.
Alternatively, the dispatcher can assign a priority level to the group and
transmit that information with the group assignments to the base station 2
and ultimately to the subscriber units 6. In any event, the controller 128, in
addition to storing the group assignments, stores the priority level of the
group in its memory. In a preferred embodiment, there are two priority
~ Ievels, high and low. In an aiternate embodiment, there are a plurality of
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priority levels which can be assigned to each of the groups.
Referring back to FIG. 12, if priority scan has been disabled, then
after step 408 the controller 128 performs other tasks. If, however, priority
scan has been enabled, then in step 410, the controller 128 accesses the
priority level of the dispatch communication being processed and the priority
Ievel of the newly received dispatch communication. The controller 128
then compares these priority levels. If the priority level of the newly
received dispatch communication is less than or equal to the priority level of
the dispatch communication being processed, then the controller 128 goes
on to perform other processing steps. If, however, the priority level of the
newly received dispatch communication is greater than the priority level of
the dispatch communication being processed, the controller 128 in step 412
causes the newly received dispatch communication to be received by the
subscriber on the subscriber terminal 14.
Referring now to FIG. 13, the steps performed by the controller 128 in
the radio unit 12 when implementing the scan nuisance delete function are
illustrated. In step 440, the controller 128 determines whether the
subscriber has enabled the scan nuisance delete function.
In a preferred embodiment, this function is enabled or disabled by the
subscriber during the setup mode. As before, the subscriber enters the
setup mode by selecting the SETUP button 39 on the keypad 26. During
setup, the subscriber will be prompted to either enable or disable the scan
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nuisance function. If the scan nuisance function is enabled, the subscriber
will also be prompted to enter one or more groups which are to be deleted
and to enter a length of time.
Referring back to FIG. 13, the subscriber terminal 14 transmits control
information to the radio unit 12 that indicates whether the scan nuisance
delete function is enabled or disabled and if enabled, which group or groups
are to be deleted and a length of time the deletion shall be implemented.
The controller 128 receives this information and, in step 442, determines
which group or groups to delete from the scan list. In step 444, the
controller 128 determines the length of time the group or groups shall be
deleted from the scan list.
Next, in step 446, in a preferred embodiment, the controller 128
prompts the subscriber terminal 14 to ask the subscriber for a password that
indicates that the subscriber is authorized to enable the scan nuisance delete
function. If the subscriber enters an incorrect password, then the controller
128 proceeds to other processing steps. If the subscriber enters a correct
password, then in step 448 the controller 128 causes the group or groups
selected by the subscriber to be deleted from the scan list for the length of
time selected by the subscriber. Then, in step 4~0, the controller 128, after
the passage of the selected length of time, causes the deleted group or
groups to be added back to the scan list.
~ In accordance with another preferred embodiment, the controller 128
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chec~s the priorit~/ of each of the groups seiected for tempor2 ~ deletion.
This priority can be set as previously described -- either by the subscriber or
by the dispatcher at the dispatcn station. When the scan nuis2nce delete
function is enabled, the controller 128, before deleting any grGups from the
scan list, checks the priority of each of the groups selected fcr deietion. If
the priority exceeds a predetermined threshold which is preferebly set by the
dispatcher at the dispatch station 4, then that group is not de!e~ed from the
scan list by the controller 128. Then the controller 128 sends a control
signal to the subscriber terminal 14 to inform the subscriber that the group
could not be deleted because of its priority level.
Referring to FIG. 14, the steps performed by the subscriber unit 6 to
implement the time scan disable function are illustrated. In step 460, the
controller 128 determines whether the time scan disable function is enabled
or disabled. This function is preferably enabled or disabled by the subscriber
in the setup mode, which is entered into by selecting the SETUP button 39.
During the setup mode, if the time scan disable function is enabled, the
subscriber can aiso enter a time which will be the time that the scanning
function is disabled(Step 462). This information is transmitted to the controller 128 so
that the controller 128 can determine the length of time that the scanning
function should be disabled for.
In accordance ~vith a preferred embodiment of the present invention, if
the subscriber attempts to enable the time scan disable function, the
2~
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subscriber terminal 14, in step 464 asks the subscriber for a password. The
password is preferably set by the dispatcher from the dispatch station
through transmissions through the base station 2. The subscriber then
enters the password. If the password is incorrect, the microprocessor 50 in
the subscriber terminal 14 determines that the subscriber is not authorized to
enable the time scan disable function. If the password is correct, then the
microprocessor 50 transmits the instruction to the controller 128 to stop the
scanning function.
In step 466, the controller 128, when it receives the instruction from
the microprocessor 50, stops scanning the previously described list of
groups that the subscriber belongs to. Part of the instruction sent by the
microprocessor 50 is the disabling time selected by the subscriber. The
controller 128 keeps the scanning function disable for the selected length of
time. Then, after the passage of the selected period of time, the controller
128 causes the scanning function to begin again.
It is understood that changes may be made in the above description
without departing from the scope of the invention. It is accordingly intended
that all matter contained in the above description and in the drawings be
interpreted as illustrative rather than limiting.
