Reliable wireless message distribution system

An acknowledge-back selective call system (100) transmits a first acknowledge-back page (300) that includes a first message data (306) and address information (302) that matches a first predetermined address (140) at an acknowledge-back selective call transceiver (130) and a second acknowledge-back page (300) that includes a second message data (306) and address information (302) that matches a second predetermined address (142) at the acknowledge-back selective call transceiver (130). The acknowledge-back selective call transceiver (130) receives the second acknowledge-back page (300), and, in response thereto, transmits an acknowledge-back confirmation response (500), the acknowledge-back confirmation response (500) including a message reception status information (502) indicating a message reception status for the first acknowledge-back page (300) and a message reception status information (504) indicating a message reception status for the second acknowledge-back page (300).

FIELD OF THE INVENTION 
This invention relates in general to selective call communications and more 
specifically to a method and apparatus for increasing communication 
throughput and for reducing contention among transmissions in a two-way 
selective call system. 
BACKGROUND OF THE INVENTION 
Contemporary selective call systems, e.g., paging systems, employ messaging 
schemes that can typically deliver voice, numeric, or alphanumeric 
messages to subscribers. The majority of selective call systems transmit 
address and message information using a communication protocol such as 
Great Britain's Post Office Code Standardization Advisory Group, POCSAG, 
or Motorola's Golay Sequential Code, GSC. More recently, the ReFlex.TM. 
protocol of Motorola, Inc., of Schaumburg, Ill. allows selective call 
systems to handle two-way communication, e.g., acknowledge-back (ack-back) 
messaging, with portable transceivers, such as with the Motorola Tango.TM. 
personal messaging unit (PMU), or pager. In an ack-back communication 
system a central system can send wireless messages to a portable 
transceiver unit such as a PMU, and the PMU can send wireless messages to 
the central system. 
Two-way communication allows a central system to verify that a portable 
transceiver unit (portable unit) received a wireless message transmitted 
by the central system and destined for reception by the portable unit. A 
confirmation wireless message, e.g., an ack-back response message, sent 
from the portable unit back to the central system in response to having 
received a wireless message therefrom provides an affirmative confirmation 
back to the central system that the wireless message was reliably 
delivered and received by the portable unit. This handshake messaging, 
i.e., sending a confirmation response message back to a central system for 
each wireless message received by a portable unit, can significantly 
enhance the reliability of communication in a selective call system. 
However, the increased number of transmitted messages due to the handshake 
messaging increases the message communication and message processing time 
delays in the selective call system. This added delay tends to reduce the 
message communication efficiency of the selective call system, which may 
not be acceptable under certain operational conditions of the selective 
call system, as will be discussed below. 
Under certain operational conditions in the selective call system, for 
example, messaging traffic may be high for an available message 
communication throughput capacity for the selective call system. Any 
significant additional message traffic can detrimentally affect the 
operational efficiency of system resources, such as limited by a messaging 
throughput capacity of a wireless communication channel, or limited by 
messaging throughput capacity of communication links, or limited by an 
operational efficiency of central system resources such as near-full 
memory queues or overloading of tasks for devices that handle messaging 
operations, or a combination of all of the above communication phenomena. 
Generally, the number of messages that a selective call system can handle 
during peak communication traffic periods constrains the number of total 
customers that can be serviced by the selective call system. The total 
number of customers handled by the selective call system typically 
determines the commercial viability of the selective call system. 
Furthermore, although conventional ack-back messaging can maintain a high 
level of reliability in message communication by sending an immediate 
ack-back message in response to every wireless message received by a 
portable unit, under certain messaging conditions transmitting an 
immediate ack-back message response for every wireless message received by 
a portable unit may not be commercially practicable. 
Specifically, to enhance the likelihood of commercial viability of a 
selective call system the messaging throughput capacity of the selective 
call system should be as high as possible. Normally, a selective call 
system has a one-way messaging throughput capacity that is constrained by 
the maximum number of wireless messages that the central system can 
transmit to the portable units over a unit of time. The selective call 
system also has a two-way messaging throughput capacity that is 
constrained by the maximum number of wireless messages that the central 
system can transmit to portable units while the portable units send 
ack-back messages back to the central system in response to receiving the 
wireless messages therefrom over a unit of time. For a particular 
selective call system, the one-way messaging throughput capacity is 
normally higher than the two-way messaging throughput capacity. Therefore, 
to enhance the likelihood of commercial viability of a selective call 
system the messaging throughput capacity of the selective call system 
should be as high as possible, preferably approaching the one-way 
messaging throughput capacity that is higher than the two-way messaging 
throughput capacity. 
As a first example, under high communication traffic conditions the 
selective call system's total messaging throughput capacity can be 
significantly constrained by the messaging throughput capacity consumed by 
the portable units sending ack-back response messages to the central 
system. The additional communication traffic and processing time delays 
due to the ack-back response messages may reduce the total number of 
wireless messages that can be delivered by the selective call system 
during the high communication traffic conditions. 
As a second example, the central system may transmit a multi-recipient 
ack-back wireless message (a group page) destined for a large group of 
recipient portable units. This may be the case while providing information 
services to subscribers of the selective call system, or while providing 
data updates to members of ack-back groups in the selective call system, 
or generally while providing wireless messages to members of ack-back 
groups in the selective call system. In response to receiving the group 
page, recipient portable units would transmit back to the central system 
their ack-back response messages to confirm a message reception status for 
the group page. The large number of ack-back response messages that the 
selective call system would have to handle over a relatively short amount 
of time could severely reduce, if not totally bottleneck, the wireless 
messaging throughput of the selective call system. Such a reduction in the 
wireless messaging throughput would create significant message 
communication delays in the selective call system. Typically, this 
condition would not be acceptable to customers of the selective call 
system thereby detrimentally affecting the commercial viability of the 
selective call system. 
Thus, what is needed is a method and apparatus, in an acknowledge-back 
selective call system, for increasing the reliability of communication 
under the varying message communication traffic loads and the two-way 
messaging communication requirements of the acknowledge-back selective 
call system.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring to FIG. 1, an acknowledge-back selective call system 100 
(hereinafter, selective call system) delivers acknowledge-back pages to 
subscribers thereof, according to the preferred embodiment of the present 
invention. Preferably, the selective call system 100 utilizes the Motorola 
ReFlex.TM. communication protocol to deliver messages to and from 
subscribers of the selective call system 100. The ReFlex protocol is more 
fully described in the following U.S. Pat. applications assigned to the 
assignee of the present invention: Ser. No. 08/131,243 entitled "Method 
and Apparatus for Identifying a Transmitter in a Radio Communication 
System" filed Oct. 4, 1993 by Simpson et al.; U.S. Pat. Ser. No. 
08/398,274 entitled "Method and Apparatus for Optimizing Receiver 
Synchronization in a Radio Communication System" filed Mar. 3, 1995 by 
Ayerst, et al.; U.S. Pat. Ser. No. 08/404,698 entitled "Method and 
Apparatus for Improved Message Reception at a Fixed System Receiver" filed 
Mar. 15, 1995 by Ayerst et al.; U.S. Pat. Ser. No. 08/498,212 entitled 
"Forward Channel Protocol to Enable Reverse Channel Aloha Transmissions" 
filed Jul. 5, 1995 by Ayerst et al.; and U.S. Pat. Ser. No. 08/502399 
entitled "A System and Method for Allocating Frequency Channels in a 
Two-way Messaging Network" filed Jul. 14, 1995 by Wang et al., which are 
hereby incorporated by reference herein. However, any conventional 
wireless communication protocol that supports two-way paging communication 
can be utilized by the selective call system 100. 
Specifically, an acknowledge-back central system 102 (hereinafter, central 
system 102) is coupled to at least one message originating device 104, 
such as via a public switched telephone network 106 (PSTN). The message 
originating device 104 comprises, for example, a telephonic entry device 
that utilizes dual tone multi-frequency (DTMF) signaling, or a computing 
device and modem arrangement utilizing modem signaling, or a page entry 
terminal device, or other message originating device that can be coupled 
via a telephone network. Further, a message originating device 104 that 
comprises a computing device can couple to the central system 102 via 
other network interfaces, such as via an Internet network interface, via 
an ethernet network interface, or via other high speed network interface, 
or even via a dedicated line interface between the message originating 
device 104 and the central system 102. Furthermore, a message originating 
device 104 that comprises a wireless network interface can couple to the 
central system 102 via a wireless network, such as an infrared 
communication network or a terrestrial or satellite-based radio frequency 
(RF) communication network. 
An input controller 108 comprises a network interface for the central 
system 102 compatible with the type of network being used to couple 
messages from a message originating device 104. For example, the input 
controller 108 comprises a telephone interface to couple messages via the 
PSTN 106. A central system controller 110 controls the acknowledge-back 
paging function of the central system 102. The central system controller 
110 is coupled to the input controller 108 for receiving messages 
associated with acknowledge-back page requests, such as that originated 
from the message originating device 104. 
The central system controller 110 is coupled to a message memory 112 for 
storing acknowledge-back messages and associated information. The message 
memory 112 is preferably a non-volatile memory. The central system 
controller 110 is also coupled to an output controller 114 for 
transmitting outbound acknowledge-back pages containing messages or 
information for subscribers of the central system 102. 
The central system controller 110 is also coupled to a timer 116 for 
keeping track of time and date information for the central system 102. The 
central system controller 110 can utilize the time and date information 
provided by the timer 116, for example, for scheduling transmission of 
acknowledge-back pages at predetermined times, as will be more fully 
discussed below. 
The central system controller 110 is coupled to a confirmation response 
tracking database memory 118. The confirmation response tracking database 
memory 118 is utilized by the central system 102 to keep track of 
acknowledge-back paging status for subscribers of the selective call 
system 100, as will be more fully discussed below. 
The output controller 114 is coupled via a communication link 120 to at 
least one acknowledge-back transceiver or selective call transceiver base 
station 122 (hereinafter, base station 122) that is typically located in a 
predefined coverage area 124. The coverage area 124 comprises a region, 
such as a geographical region, for conducting wireless message 
communication between the base station 122 and the at least one ack-back 
capable selective call transceiver 130 (pager). The selective call system 
100 typically comprises a plurality of predefined coverage areas that 
cover, for example, a wide geographical territory. 
The communication link 120 can comprise a direct wireline communication 
link, a modem communication link such as over a telephone network, a 
satellite communication link, an RF communication link, or other 
contemporary communication linking means, or a combination of the 
aforementioned communication links. The base station 122 operates to 
transmit an outbound acknowledge-back page 126 (hereinafter, page 126) to 
at least one acknowledge-back selective call transceiver 130 (hereinafter, 
selective call transceiver 130) located within the coverage area 124. 
Further, the base station 122 receives an inbound acknowledge-back 
confirmation response, or ack-back response, 128 transmitted by the at 
least one selective call transceiver 130. The base station 122 forwards 
the ack-back response 128, via the communication link 120, to the output 
controller 114 of the central system 102. In this way, the central system 
102 transmits a page 126 to the at least one selective call transceiver 
130, and then receives an ack-back response 128 therefrom to confirm a 
message reception status of the page 126 for the at least one selective 
call transceiver 130. This two-way paging communication between the 
central system 102 and the at least one selective call transceiver 130 
provides affirmative confirmation to the central system 102 that page 126 
transmitted to the at least one selective call transceiver 130 was 
successfully received thereby. This message confirmation mechanism 
increases the overall reliability of a message delivery system because it 
allows the selective call system 100 to re-transmit a message to the 
selective call transceiver 130 until the selective call transceiver 130 
acknowledges that the message was successfully received by the selective 
call transceiver 130. 
The hardware of the central system controller 110 preferably includes a 
Wireless Messaging Gateway (WMG.TM.) Administrator|.TM. paging terminal, a 
RF-Conductor|.TM. message distributor, and a RF-Usher|.TM. multiplexer, 
manufactured by Motorola, Inc. The controller has software elements and 
preferably runs under a UNIX operating system. The software elements are 
modified in accordance with the present invention. The hardware of the 
base station 122 preferably includes a Nucleus.RTM. Orchestra|.TM. 
transmitter and a RF-Audience|.TM. receiver, manufactured by Motorola, 
Inc. A more detailed description of the hardware of the central system 
controller 110 and of the base station 122 is described in "Introduction 
to The Wireless Concert|", published 1995 by Motorola, Inc., which is 
available for sale to the public as part No. 6880491G01 from Motorola, 
Inc., Ft. Worth, Tex., and which is hereby incorporated by reference 
herein. 
The operation of the selective call transceiver 130 is described more fully 
in U.S. Pat. No. 5,124,697 entitled "Acknowledge Back Pager" issued Jun. 
23, 1992 to Moore; U.S. Pat. No. 5,153,582 entitled "Method and Apparatus 
for Acknowledging and Answering a Paging Signal" issued Oct. 6, 1992 to 
Davis; and U.S. Pat. No. 4,875,038 entitled "Frequency Division 
Multiplexed Acknowledge Back Paging System" issued Oct. 17, 1989 to Siwiak 
et al., which are assigned to the assignee of the present invention and 
which are hereby incorporated by reference herein. The ack-back capable 
selective call transceiver 130 is preferably a Motorola Tango.TM. pager 
modified to perform the operations described hereinafter. The Tango pager 
is compatible with the ReFlex protocol. The Tango pager is described more 
fully in the Motorola Product Family 255 Service Manual published 1995 by 
Motorola, Inc., and in the Motorola Product Family 255 Series Controller 
Supplement, published 1995 by Motorola, Inc., which are available for sale 
to the public from Motorola Paging Products Group, Boynton Beach, Fla. as 
part No. 6881024B80 and part No. 68881104B36, respectively, and which are 
hereby incorporated by reference herein. A software element, residing in 
non-volatile memory, preferably read-only memory (ROM), of selective call 
transceiver 130 is modified to operate the microprocessor, preferably a 
Motorola M68HC11PH8, within the pager in accordance with the invention. A 
person skilled in the art of programming modifies the software using a 
Motorola HC11 Reference Manual, published 1991 by Motorola, Inc., and 
using a Motorola MC68HC11PH8 Technical Data, published 1995 by Motorola, 
Inc., which are available for sale to the public from Motorola, Inc., 
Phoenix, Ariz. 
An selective call transceiver 130 may not reliably receive the page 126, or 
may even miss the page 126, because of certain communication conditions 
related to the selective call system 100. For example, a selective call 
transceiver 132 can be located at a fringe region of the coverage area 124 
where certain wireless communication phenomena such as noise interference 
and other interference signals can detrimentally affect the reliable 
reception of pages. A selective call transceiver 134 can be located, as a 
second example, outside of the coverage area 124 consequently not being 
capable of receiving pages 126. Furthermore, the selective call 
transceiver 130, even if located within the coverage area 124, can miss 
reception of a transmitted page 126. For example, a physical blocking 
structure, e.g., a steel beam structure in a building or other similar RF 
blocking structure, can be located within the coverage area 124 interposed 
between the base station 122 and the selective call transceiver 130 
thereby preventing a transmitted signal comprising page 126 from reaching 
the selective call transceiver 130. Additionally, the power of the 
selective call transceiver 130 can have been turned off at the time when 
the signal comprising the page 126 was transmitted by the base station 
122. Consequently, the selective call transceiver 130 would not receive 
the transmitted page 126 from the base station 122. 
Under certain communication conditions, it can be undesirable for the at 
least one selective call transceiver 130 to transmit the ack-back response 
128 to the central system 102. For example, under high message 
communication traffic conditions, such as can exist from time to time in 
the coverage area 124 or in the communication link 120, the 
acknowledge-back message communication throughput capacity of the 
selective call system 100 can severely limit the number of additional 
wireless pages 126 (i.e., a single recipient acknowledge-back page) that 
can be handled by the selective call system 100. The additional message 
communication and processing time required to transmit ack-back responses 
128 to the central system 102 for the pages 126 that were received by the 
at least one selective call transceiver 130 consume the available message 
communication throughput capacity. This available message communication 
throughput capacity could be alternatively better utilized to transmit 
additional wireless pages 126 without immediately transmitting the 
ack-back responses 128 therefor to help improve the overall wireless 
message communication throughput of the selective call system 100, such as 
during peak message communication traffic conditions. 
As a second exemplary communication condition, a multi-recipient 
acknowledge-back page (hereinafter, group page) is transmitted by the 
selective call system 100 for reception by a large group of selective call 
transceivers 130, 132, 134. The selective call system 100 broadcasts, via 
at least one multi-recipient page, many different types of information to 
subscribers of the selective call system 100. For example, the selective 
call system 100 can broadcast information services such as news, weather, 
sports, financial information and other useful information to subscribers 
of the selective call system 100. The selective call system 100, as a 
second example, can broadcast at least a portion of a software program for 
delivering software updates, via at least one group page, to subscribers 
of the selective call system 100 and to the software update service. As a 
third example, the selective call system 100 can broadcast, via at least 
one group page, group messages to members of the group, such as a work 
group, or a group of family members or friends. 
A transmission of a group page to a large group of selective call 
transceivers 130, 132, 134, such as discussed above, can result in 
significantly increased message communication traffic and a long 
processing delay to acknowledge reception of the group page from the 
members of the large group of selective call transceivers 130, 132, 134. 
The increased message communication traffic and the long processing delay 
can bottle-neck message communication traffic in the selective call system 
100. This bottle-neck condition and the associated communication delays 
can severely inconvenience subscribers of the selective call system 100. 
The selective call system 100 can improve the overall message 
communication throughput and avoid a bottle-neck condition by, for 
example, temporarily inhibiting the wireless transmission of the ack-back 
responses 128 from the large group of selective call transceivers 130, 
132, 134, until a later time and while maintaining reliable wireless 
message communication for the group page, as will be more fully discussed 
below. 
In summary, under a number of acknowledge-back paging conditions, as 
discussed above, it can be undesirable, and even unnecessary, for the at 
least one selective call transceiver 130 to immediately transmit back to 
the central system 102 a confirmation via the ack-back response 128. It 
can be more advantageous for the ack-back response 128 to be transmitted 
at a later time, and under different message traffic conditions, as will 
be more fully discussed below. 
The at least one selective call transceiver 130 can be selectively 
addressed by the selective call system 100 by transmitting a page 126 that 
comprises address information that matches predetermined address 
information at the at least one selective call transceiver 130. For 
example, the at least one selective call transceiver 130 comprises an 
address memory that contains a first predetermined address information 140 
and a second predetermined address information 142. The selective call 
transceivers 130, 132, 134, in the selective call system 100 likewise can 
be configured with predetermined address information to be selectively 
addressable by more than one address in the selective call system 100. 
For example, the second selective call transceiver 132 comprises a first 
predetermined address 144, i.e., with an exemplary address value of 3, and 
a second predetermined address 146, i.e., with an exemplary address value 
of 4. Additionally, a third selective call transceiver 134 comprises a 
third predetermined address 148, with an exemplary address value of 5, and 
a second predetermined address 150, with an exemplary address value of 6. 
The selective call transceivers 130, 132, 134, individually comprising a 
plurality of predetermined addresses can each be selectively addressed by 
the selective call system 100 transmitting a page 126 comprising address 
information that matches at least one of the plurality of predetermined 
addresses of the selective call transceivers 130, 132, 134. 
The at least one selective call transceiver 130, for example, is configured 
to be individually selected by a page 126 comprising address information 
that matches a second predetermined address information 142 at the 
selective call transceiver 130. Further, the at least one selective call 
transceiver 130 can be a member of a large group of selective call 
transceivers 130, 132, 134, that is selectively addressable by a group 
address that matches the first predetermined address information 140 of 
the at least one selective call transceiver 130. This group addressing 
scheme will be more fully discussed below. 
An addressing scheme for an acknowledge-back group can utilize a common 
predetermined address information for each of the members of the 
acknowledge-back group. For example, the first predetermined address 140 
at the at least one selective call transceiver 130, and the first 
predetermined address 144 at the second selective call transceiver 132, 
and the first predetermined address 148 at the third selective call 
transceiver 134 all match the same group address information for an 
acknowledge-back group. In this way, the selective call system 100 can 
transmit a page comprising a single group address to select all the 
members of the acknowledge-back group. 
Alternatively, members of the acknowledge-back group can each have 
different predetermined address information mapped to the acknowledge-back 
group at the central system 102. In this group addressing scheme, the 
selective call system 100 transmits a group page comprising a plurality of 
addresses for selectively addressing all of the members of the 
acknowledge-back group. 
Of course, a combination of the two addressing schemes discussed above can 
also be utilized by an selective call system 100 whereby a portion of the 
members of an acknowledge-back group are selectively addressed by a single 
group address while the remaining members of the acknowledge-back group 
are each selectively addressed by different address information. The group 
page, in this case, would comprise a plurality of addresses for 
selectively addressing all of the members of the acknowledge-back group. 
Therefore, the at least one selective call transceiver 130 comprising a 
plurality of predetermined address information 140, 142, can be 
selectively addressed by the selective call system 100 as an individual 
subscriber to the selective call system 100 or as a member of an 
acknowledge-back group in the selective call system 100. 
According to the preferred embodiment of the present invention, the 
selective call system 100 can determine when the at least one selective 
call transceiver 130 should not immediately transmit back an 
acknowledge-back confirmation response, e.g., the ack-back response 128, 
to acknowledge a message reception status of a previously transmitted page 
126. 
For example, if the selective call transceivers 130, 132, 134, are members 
of a large acknowledge-back group, the selective call system 100 inhibits 
the wireless transmission of the ack-back responses 128 from the members 
of the large acknowledge-back group. The members of the large 
acknowledge-back group inhibit their ack-back responses 128, as a first 
example, by recognizing that they received a group page 126 and that they 
are members of the acknowledge-back group being selectively addressed by 
the group page 126. The selective call transceivers 130, 132, 134, for 
example, are pre-configured to recognize their membership in the 
acknowledge-back group. The members of the large acknowledge-back group 
inhibit their ack-back responses 128, as a second example, by receiving an 
instruction in the group page 126, such as within a page header field (not 
shown) in the group page 126, that instructs the members of the large 
acknowledge-back group to inhibit wireless transmission of their ack-back 
responses 128 for the group page 126. 
The at least one selective call transceiver 130, for example, can save its 
ack-back response 128 for transmission at a later time, such as when 
conditions have changed for the communication channel for the selective 
call system 100. The at least one selective call transceiver 130, 
according to the preferred embodiment of the present invention, can 
wirelessly transmit its ack-back response 128 as part of a subsequent 
transmission to the central system 102, which will be more fully discussed 
below. In this way, the message communication throughput and the message 
communication reliability of the selective call system 100 are maintained 
at relatively high levels during varying message communication traffic 
conditions, and where an ack-back response 128 for every page 126 is not 
always necessary at the present time. Referring to FIG. 2, an selective 
call transceiver 130 is shown according to the preferred embodiment of the 
present invention. The selective call transceiver 130 preferably operates 
under the ReFlex protocol to receive pages 126 from the central system 102 
and to transmit ack-back responses 128 back to the central system 102. 
However, any conventional wireless communication protocol that supports 
two-way paging communication can be utilized by the selective call 
transceiver 130 as supported by the selective call system 100. 
The selective call transceiver 130 comprises an antenna 202 coupled to a 
transceiver 204 for receiving and for wirelessly transmitting messages in 
the selective call system 100 of FIG. 1. The transceiver 204 includes a 
receiver for receiving pages that were wirelessly transmitted in the 
selective call system 100. The wireless transceiver 204 also includes a 
transmitter for wirelessly transmitting an acknowledge-back confirmation 
response. 
A decoder 206 is coupled to the transceiver 204 and to a controller 210 for 
decoding received messages, such as from pages 126 destined for the 
selective call transceiver 130. An encoder 208 is coupled to the 
transceiver 204 and to the controller 210 for encoding messages that are 
transmitted from the selective call transceiver 130 to the central system 
102, such as the ack-back response 128. The controller 210 is coupled to 
the transceiver 204 via a control line to control the mode of operation of 
the transceiver 204, such as for receiving messages or for transmitting 
messages via the antenna 202. 
The controller 210 is coupled to an address memory 212 that is preferably a 
non-volatile memory. The address memory 212 stores the predetermined 
address information, such as the first predetermined address 140 and the 
second predetermined address 142 shown in FIG. 1. When the decoder 206 
decodes a page and couples the information associated with the page to the 
controller 210, the controller 210 compares the address information from 
the page to the predetermined address information stored in the address 
memory 212. If the controller 210 determines a match exists between the 
address information from the page and the predetermined address 
information in the address memory 212 then the controller 210 stores an 
acknowledge-back message from the page into a message memory 214. The 
message memory 214 is preferably a non-volatile memory, such as battery 
backed-up RAM. 
The controller 210 is coupled to a sensible alert means 216, such as an 
audible alert transducer or a tactile alert transducer. The audible alert 
transducer provides an audible alert to a user of the selective call 
transceiver 130, while the tactile alert transducer provides a silent 
alert to the user. The type of alert that is provided to a user will 
typically be pre-configured by a selection made by the user via a user 
input means 220 that is coupled to the controller 210. The user input 
means 220 may comprise buttons, keys, touch pads, or switches, such as for 
providing a user of the selective call transceiver 130 with a means of 
entering information and controlling the functions of the selective call 
transceiver 130. Consequently, after the controller 210 determines a match 
exists between the address information from the page and a predetermined 
address in the address memory 212, the controller 210 alerts, either 
audibly or silently as configured for the selective call transceiver 130, 
the user of the selective call transceiver 130 via the sensible alert 
means 216 that a page has been received. 
The controller 210 is coupled to a display 218, for providing visual 
information to the user of the selective call transceiver 130. The display 
218 preferably comprises a liquid crystal display. The display 218, the 
user input means 220, and the sensible alert means 216, constitute a user 
interface for the user of the selective call transceiver 130. 
When the user is informed of the reception of the page, such as via the 
sensible alert means 216, the user can operate the user input means 220 to 
request that the received acknowledge-back message be displayed on the 
display 218. The controller 210, in response to the activated user input 
means 220, couples the acknowledge-back message from the message memory 
214 to the display 218 for viewing by the user. Furthermore, the user can 
operate the user input means 220 to send a message back to the central 
system 102 and thereby to a caller, such as a message originating device 
104. The user would send the message as part of an ack-back response 128 
transmitted from the selective call transceiver 130. The user configures a 
message to be included with the ack-back response 128, or the user selects 
one message from a set of pre-configured messages to include in the 
ack-back response 128, or the user may utilize a combination of both 
methods. 
The controller 210 is coupled to a non-volatile data memory 222 that can 
alternatively comprise a program memory 224, a parameter memory 226, other 
non-volatile data storage, or a combination thereof as may be configured 
for the selective call transceiver 130 for a particular implementation of 
the selective call system 100. The non-volatile data memory 222 can store 
information that is updated by the controller 210 using information from a 
message provided by at least one page received by the selective call 
transceiver 130, as will be more fully discussed below. 
For example, a computer program is stored in the program memory 224. The 
computer program, for example, provides instructions and data for 
controlling execution of functions performed by a computer. The computer, 
in a first exemplary configuration, comprises the controller 210. However, 
the computer does not have to include the controller 210, and, in a second 
exemplary configuration can include a computing device that is external to 
the selective call transceiver 130 and coupled thereto via a computer 
interface (not shown) in a manner well known in the art. 
The controller 210 upon receiving a page 126 retrieves a message from the 
page 126 and utilizes information from the message to update the computer 
program that is stored in the program memory 224. This page 126, in one 
system implementation, comprises an acknowledge-back group page for 
providing an efficient and reliable means for mass distribution of 
software updates that are transmitted through wireless communication in 
the selective call system 100 to members of an acknowledge-back group in 
the selective call system 100. By utilizing an acknowledge-back group page 
to mass distribute the software updates, the selective call system 100 can 
confirm the reliable reception of the software updates by the members of 
the acknowledge-back group by monitoring the ack-back responses 128 from 
the selective call transceivers 130, 132, 134, that are members of the 
acknowledge-back group. Further, by inhibiting wireless transmission of 
ack-back responses 128 from the selective call transceivers 130, 132, 134, 
at the present time, and by deferring transmissions of the ack-back 
responses 128 to a later time, the selective call system 100 can level its 
wireless message communication traffic loads over time and maintain a 
relatively high wireless message communication throughput while reliably 
delivering the software updates to the members of the acknowledge-back 
group, as will be more fully discussed below. 
In a similar fashion, the data stored in the parameter memory 226 can be 
updated through pages 126 in the selective call system 100. The selective 
call system 100 can defer transmissions of the ack-back responses 128 from 
the selective call transceivers 130, 132, 134, to a later time to maintain 
a relatively high wireless message communication throughput while reliably 
delivering the data updates. Additionally, in likewise fashion, a database 
stored in the non-volatile data memory 222 could similarly be updated via 
reliable wireless message communication in the selective call system 100. 
A timer 228 is coupled to the controller 210 for providing time and date 
information to the controller 210. The controller 210 could utilize the 
time and date information provided by the timer 228, for example, to 
activate or disable functions for the selective call transceiver 130 at 
predetermined times. The controller 210 is also coupled to a power 
conservation module 230 that is further coupled to the transceiver 204 to 
conserve power in a power source not shown during predetermined time 
intervals in accordance with a power conservation scheme. In one preferred 
mode of operation, the central system 102 can transmit at least one group 
page to the selective call transceivers 130, 132, 134, that are members of 
an acknowledge-back group to inform the selective call transceivers 130, 
132, 134, when a subsequent group page will be transmitted to them. The 
subsequent group page would contain, for example, a large message 
comprising a software update. By informing the selective call transceivers 
130, 132, 134, of a future time interval when the software update will be 
transmitted in the selective call system 100, it also instructs the 
selective call transceivers 130, 132, 134, to override a power off state 
and to make certain that the selective call transceivers 130, 132, 134, 
will be turned on and operating to receive the subsequent group page 
during the future time interval. Therefore, the timer 228 at the selective 
call transceiver 130 and the timer 116 at the central system 102 can help 
the selective call system 100 schedule messages, such as long messages in 
acknowledge-back group pages, to time intervals where message 
communication traffic is expected to be much lower. This can additionally 
help to level message communication traffic over time in the selective 
call system 100 to maintain a relatively high message communication 
traffic throughput while reliably delivering messages to subscribers of 
the selective call system 100. 
Referring to FIG. 3, an exemplary page 300 is shown, in accordance with a 
preferred embodiment of the present invention. The page 300 comprises 
address information that can include one or more addresses for selectively 
addressing an selective call transceiver 130 as an individual subscriber 
or for addressing a group of selective call transceivers 130, 132, 134, in 
the selective call system 100. Optionally, a response status information 
304 is included in the page 300 to indicate to the selective call 
transceiver 130 certain information relating to an page or to an 
acknowledge-back confirmation response from the selective call transceiver 
130, as will be more fully discussed below. 
The response status information 304 preferably includes message 
identification information (not shown), such as a message identification 
number, that identifies a message, such as the message being transmitted 
with the page 300. Optionally, the response status information 304 also 
includes address information coupled to the message identification 
information to identify a message transmitted in a page. 
The selective call transceiver 130 and the central system 102 can utilize 
the message identification number to communicate between each other a 
message reception status, or other information, associated with the 
message identified by the message identification number. As a first 
example the response status information 304 includes an instruction to 
instruct the selective call transceiver 130 to remain powered on during a 
future time interval to operate to receive a subsequently transmitted page 
300 during the future time interval, as has been discussed above with 
respect to the timer 228. Further, the response status information 304, as 
a second example, includes an instruction to instruct the selective call 
transceiver 130 to inhibit the wireless transmission of an ack-back 
response 128 at the present time. Alternatively, when an ack-back response 
128 is desired by the central system 102, the response status information 
304 includes an instruction to instruct the selective call transceiver 130 
to wirelessly transmit the ack-back response 128. The central system 102 
also can instruct the selective call transceiver 130 via an instruction in 
the response status information 304 to wirelessly transmit the ack-back 
response 128 during a predetermined time interval and according to other 
communication parameters for the selective call system 100. 
The central system 102 optionally includes in the response status 
information 304 of a current page 300 a message identification 
information, such as a message identification number, and/or address 
information, to identify a message that was transmitted in a previous page 
300. The selective call transceiver 130 would subsequently transmit an 
ack-back response 128 in response to the current page 300. The ack-back 
response 128 would include an acknowledgment including a message reception 
status information for the message that was transmitted in the previous 
page 300. The message reception status information would include, for 
example, a message identification number and/or address information to 
identify the message transmitted in the previous page 300. In this way, 
the central system 102 can affirmatively request that the selective call 
transceiver 130 transmit an acknowledgment for a particular message that 
was previously transmitted thereto, and to include the acknowledgment in 
the ack-back response 128 in response to the current page 300. 
Note that including in the response status information 304 of the current 
page 300 an express identification of a message transmitted in a previous 
page 300 is an optional feature. For example, the selective call 
transceiver 130 can be pre-configured to always respond in the current 
ack-back response 128 with a message reception status information 
indicating a message reception status of at least one previously 
transmitted message, such as a previously transmitted message whose 
ack-back response 128 was previously inhibited from wireless transmission 
back to the central system 102. 
The use of the response status information 304 is optional for an selective 
call system 100. For example, an selective call transceiver 130 is 
pre-configured to inhibit wireless transmission of an ack-back response 
128 as a response to an acknowledge-back group page. In this case, the 
selective call transceiver 130 stores information for the ack-back 
response 128, such as in the message memory 214, to include the 
information in a subsequent ack-back response 128 that would respond to 
both a subsequent page 126 and to the current page 126. 
Additionally, the page 300 comprises message data 306 which constitutes the 
acknowledge-back message being transmitted with the page 300. The message 
data 306, for example, includes an information service update, or a 
computer program update, or a data update, as discussed above, that is 
destined for reception by a group of selective call transceivers 130, 132, 
134. 
Referring to FIG. 4, an exemplary acknowledge-back message database 400 for 
a group of selective call transceivers 130, 132, 134, is shown according 
to the preferred embodiment of the present invention. The acknowledge-back 
message database 400 for the group can be stored in the confirmation 
response tracking database memory 118 that is shown in FIG. 1. The central 
system, 102 utilizes the acknowledge-back message database 400 to keep 
track of acknowledge-back paging status for members of an acknowledge-back 
group. The central system 102 updates the acknowledge-back paging status 
for the members of the acknowledge-back group as the central system 102 
receives and processes ack-back responses 128 from the members of the 
acknowledge-back group, as will be more fully discussed below. 
In this example, the acknowledge-back message database 400 comprises 
information for a message destined for reception by members of an 
acknowledge-back group. The acknowledge-back message database 400 for the 
group, in this example, is identified by an acknowledge-back group 
identification number and a message identification number. In this case, 
the group identification number is one and the message identification 
number is one. The acknowledge-back message database 400, therefore, 
tracks acknowledge-back paging status information for message number one 
destined for reception by the members of the acknowledge-back group number 
one. 
Each of the group members is identified by an address that corresponds to 
the particular group member, as illustrated by the group member address 
column 402. In this example, the acknowledge-back group comprises the 
selective call transceivers 130, 132, 134, that are shown in FIG. 1. The 
first predetermined address 140, 144, 148, for each of the selective call 
transceivers 130, 132, 134, respectively, comprises a common group 
address. The second predetermined address 142, 146, 150, for each of the 
selective call transceivers 130, 132, 134, respectively, comprises an 
individual acknowledge-back address for each of the selective call 
transceivers 130, 132, 134. In the acknowledge-back message database 400 
for the group, in this example, the members of the acknowledge-back group 
are preferably identified by their individual subscriber acknowledge-back 
addresses. This is illustrated in the group member address column 402. 
The next column in the acknowledge-back message database 400 indicates 
acknowledge-back reception status 404 for each of the members of the 
acknowledge-back group. At the present time interval, as shown, none of 
the group members have acknowledged reception of a wirelessly transmitted 
page 300. However, when an acknowledge-back confirmation response is 
received by the central system 102 from one of the members of the 
acknowledge-back group number one for message number one, the central 
system controller 110 (FIG. 1) would update the acknowledge-back message 
database 400 for that particular member to indicate a reliable reception 
thereby of a previously transmitted page 300 comprising message number 
one. 
Optionally, the acknowledge-back message database 400 also keeps track of 
time and date information for scheduling when a next page 300 is to be 
sent to members of the acknowledge-back group number one that require a 
re-transmission of the page 300, as indicated by the acknowledged message 
reception status 404 for the members of the acknowledge-back group. The 
re-transmission of the page 300, of course, would also include message 
number one. The next time and date for transmitting the page 300 is 
preferably maintained in the acknowledge-back message database 400 for 
each of the members of the acknowledge-back group number one, for message 
number one, as shown in the next group page time and date column 406. The 
central system 102 can re-transmit the page 300 selectively addressing 
those members of the acknowledge-back group that still have not confirmed 
a reliable reception of the message number one. A re-transmission of the 
page 300 can preferably be scheduled at a certain time interval where the 
members of the acknowledge-back group that still have not confirmed a 
reliable reception of the message number one will be ready to receive the 
page 300. 
Further, the re-transmission time interval can be selected by the central 
system 102 such that the message communication traffic capacity during 
such time interval would be capable of handling the additional message 
communication traffic due to the page 300. The central system 102, for 
example, communicates the selected future time interval to the members of 
the acknowledge-back group by transmitting a page 300 that includes a 
response status information 304 identifying the next time interval for 
transmission of message number one. In this way, the central system 102 
can re-transmit the page 300 comprising the message number one, such as on 
a periodic basis, until most of the members of the acknowledge-back group 
have responded that they reliably received the message number one. The 
remaining members that have not responded to the page 300, or to 
re-transmissions thereof, over a predetermined amount of time, could be 
handled by the selective call system 100 in a number of ways. As a first 
example, a system operator could attempt to individually contact the 
remaining members that did not reliably receive the message number one. To 
contact the remaining members, for example, the operator sends individual 
pages to the remaining members. As a second example, the selective call 
system 100 could flag these members to receive periodic group pages that 
would include a brief message informing the subscribers to contact the 
central system to receive message number one, such as via a telephone 
modem communication. 
Referring to FIG. 5, an acknowledge-back confirmation response 500 from an 
selective call transceiver 130 is shown, according to the preferred 
embodiment of the present invention. The acknowledge-back confirmation 
response 500 (ack-back response) comprises an acknowledgment for a page. 
The acknowledgment preferably includes a message reception status 
information 502 that comprises an address information for indicating to 
the central system 102 the particular predetermined address of an 
selective call transceiver 130 that is being acknowledged by the ack-back 
response 500. Further, a message identification information (not shown), 
such as a message identification number, is preferably coupled to the 
address information in the message reception status information 502 in the 
acknowledgment to affirmatively identify to the central system 102 the 
particular message that is being acknowledged by the acknowledgment in the 
ack-back response 500. 
The ack-back response 500 can also include an acknowledgment to a previous 
page. This acknowledgment preferably includes a message reception status 
information 504 that comprises address information coupled to a message 
identification information, such as a message identification number (not 
shown), to acknowledge back to the central system 102 a message reception 
status of a previously transmitted page 300. The previously transmitted 
page 300 comprised a message identified by the message identification 
number. The address information of the message reception status 
information 504 corresponds to a predetermined address for the selective 
call transceiver 130. It also corresponds to address information in the 
previously transmitted page 300 having been transmitted for reception by 
the selective call transceiver 130. Note that the message identification 
information, such as the message identification numbers, are optionally 
included in the ack-back response 500. 
In summary, the selective call transceiver 130 can confirm both the current 
page 300 message reception status and at least one previous page 300 
message reception status by transmitting a single ack-back response 500 to 
the central system 102. The selective call system 100 gains significant 
advantages by utilizing a single ack-back response 500 to acknowledge two 
or more previously received pages 300 at the selective call transceiver 
130. For example, as discussed before, the selective call system 100 can 
increase communication traffic efficiency during certain high message 
communication traffic periods of time by inhibiting a wireless 
transmission response from the selective call transceiver 130 during that 
period of time, and then delivering that response in a subsequent 
wirelessly transmitted ack-back response 500 from the selective call 
transceiver 130, such as when wireless message communication traffic is 
lower for the selective call system 100. 
This mechanism for inhibiting and then deferring a confirmation response to 
be included as part as a wireless transmission of a subsequent ack-back 
response 500 can be very useful for reliably distributing a wireless 
broadcast message to a large group of subscribers, such as for delivering 
computer program updates over a wireless communication channel for the 
selective call system 100. The subscribers that receive a page 300 
comprising a computer program update message do not immediately respond 
with a confirmation of a message reception status therefor. Instead, for 
example, they can include the confirmation response as part of a 
subsequent ack-back response 500 that is normally responding to a 
subsequently transmitted page 300 for the particular subscriber. 
In this way, the selective call system 100 can avoid handling a large 
number of acknowledge-back confirmation responses over a relatively short 
time interval for confirming reception of a computer program update, which 
could unreasonably delay, or potentially block, message communication 
traffic in the selective call system 100. The selective call transceivers 
130, 132, 134, for example, can confirm back to the central system 102 
their message reception status for the computer program update as part of 
subsequent ack-back responses 500 that are also responding to other pages 
300. These subsequent ack-back responses 500 can be transmitted when 
message communication traffic is experiencing lower traffic conditions for 
the selective call system 100. This advantageously balances the message 
communication traffic loads being handled over time by the selective call 
system 100 to maintain a relatively high message communication throughput 
over time while reliably delivering the computer program update message to 
the large group of subscribers of the selective call system 100. 
Referring to FIG. 6, an exemplary acknowledge-back paging sequence between 
the central system 102 and the at least one selective call transceiver 130 
is shown, in accordance with the preferred embodiment of the present 
invention. In a first step, the central system 102 wirelessly transmits a 
first page 602 for reception by the at least one selective call 
transceiver 130. In a second step, the central system 102 wirelessly 
transmits a second page 604 destined for reception by the at least one 
selective call transceiver 130. In this example, the first page 602 
selectively addresses a first predetermined address at the selective call 
transceiver 130, while the second page 604 selectively addresses a second 
predetermined address at the selective call transceiver 130. The first 
predetermined address at the selective call transceiver 130, in this 
example, is configured as a group acknowledge-back address. The selective 
call transceiver 130, in response to receiving the first page 602 that 
selectively addresses the first predetermined address, inhibits 
transmission of an acknowledge-back confirmation response for the first 
page 602. In this way, the selective call transceivers 130, 132, 134, that 
are members of an acknowledge-back group do not immediately respond via 
wireless transmission to the first page 602 that was destined for 
reception by a group comprising the selective call transceivers 130, 132, 
134. 
However, in response to a subsequent page, such as the page 604 that 
selectively addresses a second predetermined address at the selective call 
transceiver 130, the selective call transceiver 130 wirelessly transmits 
to the central system 102 an acknowledge-back confirmation response 606 
that includes acknowledgment for the second page 604 and acknowledgment 
for the first page 602. Therefore, the selective call transceiver 130 
wirelessly transmits the acknowledge-back confirmation response 606 to 
acknowledge both the current page 604 and a previous page 602. The 
acknowledge-back confirmation response 606, in this example, identifies 
the acknowledgment to the previous page 602 by including a representation 
of the address of the previous page 602. In similar fashion in this 
example, the acknowledgment to the current page 604 includes a 
representation of the address of the current page 604 as identification of 
an acknowledgment response thereof. 
Referring to FIGS. 7, 8, 9, and 10, the flow diagrams shown illustrate a 
number of exemplary operational sequences for the selective call system 
100 of FIG. 1, including the selective call transceiver of FIG. 2, in 
accordance with the preferred embodiment of the present invention. FIGS. 
7, 8 and 10 illustrate exemplary operational sequences at the central 
system 102, while FIG. 9 illustrates an exemplary operational sequence at 
the selective call transceiver 130. 
First, in an operational sequence that is not shown in FIGS. 7, 8, 9, and 
10, the central system controller 110 (FIG. 1) couples messages comprising 
address information and message data from the input controller 108 to the 
message memory 112 for sending pages, such as sending pages, to the 
selective call transceivers 130, 132, 134, for delivering the messages to 
subscribers of the selective call system 100. As was discussed above with 
respect to the message originating device 104 in FIG. 1, the message 
originating device 104 typically couples requests to send pages to the 
input controller 108, which then couples the messages to the central 
system controller 110. The messages are then stored in the message memory 
112. Note that the requests can originate via a number of different 
interfaces between the message originating device 104 and the central 
system 102, as discussed above. 
Referring next to FIGS. 1 and 7, the central system controller 110 enters, 
at step 702, an operational sequence for controlling an acknowledge-back 
message transmission process. The central system controller 110 determines 
whether there are any acknowledge-back messages in the message memory 112 
for transmission into the selective call system 100. If there are no 
acknowledge-back messages in the message memory 112, at step 704, then the 
central system controller 110 exits this operational sequence, at step 
706, and can perform other functions for the central system 102. 
On the other hand, if an acknowledge-back message is found in the message 
memory 112, at step 704, then the central system controller 110, in this 
example, gets a message identification information, such as a message 
identification number, associated with the acknowledge-back message in the 
message memory 112 and checks the confirmation response tracking database 
memory 118 to determine if an acknowledge-back message database exists for 
the particular acknowledge-back message identification number, at step 
708. 
If no acknowledge-back message database exits in the confirmation response 
tracking database memory 118, at step 708, then the central system 
controller 110 will initialize an acknowledge-back message database for 
the current message identification number, at step 710. For example, refer 
to FIG. 4 for an illustration of an acknowledge-back message database 
representing an acknowledge-back group identified by the number one and a 
message identified by the number one. 
After the central system controller 110 locates an acknowledge-back message 
database in the confirmation response tracking database memory 118 for the 
message identification number for the acknowledge-back message in the 
message memory 112, the central system controller 110 determines whether 
it is time to transmit a page with the acknowledge-back message, at step 
712. The page would be wirelessly transmitted, in this example, to all the 
selective call transceivers 130, 132, 134, that are identified in the 
acknowledge-back message database 400 as having a page reception time that 
is currently due, as illustrated in FIG. 4. The time to transmit the page 
in this example is set for Aug. 31, 1995 at 3 am, as shown in the next 
group page time and date column 406. 
If the central system controller 110 determines, at step 712, that the time 
to transmit the acknowledge-back message is not currently due yet, then 
the central system controller 110 gets the next acknowledge-back message 
that is found in the message memory 112, at step 714, to see whether it is 
time to transmit the next acknowledge-back message. If there are no more 
acknowledge-back messages found in the message memory 112, at step 716, 
then the central system controller 110 exits the current operational 
sequence, at step 706, and can perform other functions for the central 
system 102. Otherwise, if a next acknowledge-back message is found in the 
message memory 112, then the central system controller 110 can process the 
next acknowledge-back message in a similar method, as discussed before for 
steps 708, 710, and 712, to determine if it is time to transmit the next 
acknowledge-back message. 
When it is time to wirelessly transmit an acknowledge-back message located 
in the message memory 112, at step 712, the central system controller 110 
formats the acknowledge-back message and couples address information 
thereto to provide a page that can be wirelessly transmitted using a 
communication protocol such as the ReFlex protocol. The central system 
controller 110 uses the information in the next group page time and date 
column 406 of the acknowledge-back message database 400, at step 718, to 
select the address information that is coupled to the acknowledge-back 
message to provide the page. In this way, the central system 102 only 
selectively addresses those selective call transceivers 130, 132, 134, 
that have an acknowledge page time that is currently due. Additionally, in 
this example, the central system controller 110 optionally sets a response 
status information for the page, at step 720. The response status 
information 304 in the page 300, for example as shown in FIG. 3, can 
provide additional information to the selective call transceiver 130, 132, 
134, such as with respect to the current page or with respect to a 
previous page, as was discussed above with respect to the response status 
information 304 of FIG. 3. 
After a response status information is optionally added to the page, at 
step 720, the central system 102 then wirelessly transmits the page, at 
step 722. The selective call system 100 wirelessly transmits the page into 
at least one coverage area 124 (FIG. 1) for an acknowledge-back 
communication channel. The wireless transmission of the page is handled by 
the central system controller 110 coupled to at least one output 
controller 114 that routes the page via at least one communication link 
120 to at least one base station 122. After the central system controller 
110 handles the wireless transmission of the page, at step 722, the 
central system controller 110 exits the current operational sequence, at 
step 706, and can perform other functions for the central system 102. 
Referring to FIG. 8, when the central system controller 110 determines, at 
step 720, that a response status information is necessary in the page, the 
central system controller 110 enters, at step 802, the following 
operational sequence. First, the central system controller 110 determines, 
at step 804, whether a special response mode is necessary for the current 
page. 
For example, the central system controller 110 can send an instruction to 
affirmatively instruct all the recipients of the page to inhibit wireless 
transmission of an acknowledge-back confirmation response. The central 
system controller 110, at step 806, sets the response status information 
in the page to a special response mode such as to inhibit wireless 
transmission of an acknowledge-back confirmation response from the 
recipients at this time. Alternatively, at step 808, the central system 
controller 110 can set the response status information in the page to 
normal response mode to allow, for example, the recipients of the page to 
respond with an acknowledgment. 
The central system controller 110, at step 810, determines whether the 
recipients of the page should also respond to a previous acknowledge-back 
message. If a response is called for, at step 810, the central system 
controller 110, at step 812, sets the response status information in the 
page to request a status information of a previous page message that is 
identified by a message identification information, such as a message 
identification number. Additionally, address information can be coupled to 
the message identification information in the response status information 
to identify the previous page message. The central system controller 110 
then, at step 814, exits the current operational sequence and processes 
the transmission of the page, at step 722, as discussed before for FIG. 7. 
Referring to FIG. 9, the controller 210 (see FIG. 2) of the selective call 
transceiver 130 enters an operational sequence, at step 902, for 
controlling an acknowledge-back message reception process and an 
acknowledge-back confirmation response transmission process. After the 
selective call system 100 transmits a page into at least one coverage area 
124, the selective call transceiver 130 operates to receive the page, at 
step 904. If, for example, the page comprises a computer program update 
message, then the controller 210 updates a computer program in a program 
memory 224 by utilizing the computer program update message. 
The controller 210 gets the response status information from the page that 
was optionally included in the page by the central system 102. The 
controller 210, at step 908, determines whether a special response mode is 
requested by the central system 102. If a special response mode is 
requested, at step 908, the controller 210, at step 910, inhibits an 
acknowledge-back confirmation response from being transmitted back to the 
central system 102 at this time. The controller 210 then exits the 
operational sequence, at step 912, and can perform other functions for the 
selective call transceiver 130. 
On the other hand, if a special response mode is not called for, at step 
908, then the controller 210 prepares, at step 914, an acknowledge-back 
confirmation response for immediate wireless transmission back to the 
central system 102. This acknowledge-back confirmation response, for 
example, includes an acknowledgment that the message of the current page 
was successfully received by the selective call transceiver 130. 
Alternatively, for example, the acknowledgment indicates that the message 
of the current page was not received by the selective call transceiver 
130. Other types of acknowledgment can be included in the acknowledge-back 
confirmation response to indicate other communication related status with 
respect to at least one page destined for reception by the selective call 
transceiver 130. 
Additionally, the controller 210 determines, at step 916, whether an 
acknowledge-back confirmation response is required for a previous 
acknowledge-back message. This is the case, for example, if the received 
response status information in the page specifically requests a response 
to a previous page. However, an acknowledgment to a previous page can be 
included in the current acknowledge-back confirmation response even if not 
requested by the central system 102. 
For example, a previous acknowledge-back confirmation response was 
inhibited, as indicated, for example, by information associated with a 
previous page that is stored in the message memory 214. Specifically, if a 
previous page comprises, for example, a software update to a computer 
program resident in program memory 224, or to other data stored in the 
non-volatile data memory 222, a previous acknowledge-back confirmation 
response to that page can also be stored in the message memory 214 to 
indicate to the controller 210 to include the acknowledgment in a 
subsequent acknowledge-back confirmation response for transmission to the 
central system 102. 
If a response to a previous page is required, at step 916, the controller 
210, at step 918, sets the current acknowledge-back confirmation response 
to include the acknowledgment of a previous acknowledge-back message 
identified by a message identification information, such as a message 
identification number. Then, at step 920, the controller 210 and the 
encoder 208 operate to format and encode the acknowledge-back confirmation 
response according to a communication protocol such as the ReFlex 
protocol. The controller 210 then activates the transceiver 204 to 
transmit the acknowledge-back confirmation response back to the central 
system 102. After transmitting the acknowledge-back confirmation response, 
the controller 210 exits the current operational sequence, at step 912, 
and can perform other functions for the selective call transceiver 130. 
Referring to FIG. 10, the central system controller 110 enters an 
operational sequence, at step 1002, for controlling an acknowledge-back 
confirmation response reception process, such as for receiving an 
acknowledge-back confirmation response from the selective call transceiver 
130. The central system controller 110 operates with the output controller 
114 to receive an acknowledge-back confirmation response, at step 1004. 
The central system controller 110 stores the received acknowledge-back 
confirmation response in the message memory 112. Based on the information 
contained in the acknowledge-back confirmation response 500, as shown in 
FIG. 5, the central system controller 110 updates an acknowledge-back 
message database 400, such as shown in FIG. 4, in the confirmation 
response tracking database memory 118 for an acknowledge-back message 
identified by a message identification information, such as a message 
identification number, provided in the acknowledge-back confirmation 
response, at step 1006. 
If the central system controller 110, at step 1008, determines that a 
previous acknowledge-back message is also being acknowledged in the 
current acknowledge-back confirmation response, the central system 
controller 110 then updates, at step 1010, an acknowledge-back message 
database in the confirmation response tracking database memory 118 for the 
previous acknowledge-back message identified by a message identification 
number in the acknowledge-back confirmation response. 
After updating at least one acknowledge-back message database in the 
confirmation response tracking database memory 118, the central system 
controller 110 exits the current operational sequence, at step 1012. The 
central system controller 110 can then perform other functions for the 
central system 102. 
In summary, the central system 102 can keep track of those selective call 
transceivers 130, 132, 134, that responded with an acknowledge-back 
confirmation response. The central system 102 determines from the received 
acknowledge-back confirmation responses over time which of the selective 
call transceivers 130, 132, 134, have reliably received a previously 
transmitted page. The central system 102 can determine whether a 
subsequent, duplicate page should be wirelessly transmitted to allow the 
selective call transceivers 130, 132, 134, an additional opportunity to 
reliably receive the desired acknowledge-back message. The central system 
102, for example, can wirelessly transmit a duplicate page at one or more 
selected times over a time interval to give the selective call 
transceivers 130, 132, 134, opportunity to reliably receive the page while 
maintaining a relatively high message communication traffic throughput for 
the selective call system 100. By deferring an acknowledge-back 
communication response from the selective call transceivers 130, 132, 134, 
to be included as part of subsequent acknowledge-back confirmation 
responses therefrom, the selective call system 100 can advantageously 
reduce acknowledge-back confirmation response communication traffic while 
allowing a higher level of acknowledge-back paging traffic in an 
acknowledge-back communication channel. The acknowledge-back confirmation 
response communication traffic can be deferred to a later time interval 
where the selective call system 100 can better handle the additional 
traffic. In the case of a one-channel acknowledge-back selective call 
system using time division multiplexing, the invention will advantageously 
reduce contention among both the outbound transmissions of the base 
station and the inbound transmissions of the selective call transceivers. 
In the case of a supernumerary channel acknowledge-back selective call 
system using frequency division multiplexing, the invention will 
advantageously directly reduce contention among inbound transmissions of 
the selective call transceivers, and, as a result, indirectly permit the 
immediate transmission of certain outbound messages that require an 
immediate acknowledgement. 
While a detailed description of a preferred embodiment of the invention has 
been given, it should be appreciated that many variations can be made 
thereto without departing from the scope of the invention as set forth in 
the appended claims. Further, the invention is not limited to selective 
call transceivers, or two-way pagers, but can be used with other types of 
two-way communication devices, both fixed and portable, both wireless and 
wireline.