Dynamically addressable communications system and method

A dynamically-addressable communications system provides either a list or set of dynamic addresses to selected receivers for broadcasting information packets from a transmission source to the selected receivers. Each dynamic address provided in the set is associated with a particular information packet designated to be received by the particular selected receivers to which that dynamic address is provided. Additionally, each broadcasted information packet includes at least one dynamic address identical to the dynamic address provided to its associated selected receivers. Thus, the broadcasted information packet which includes such identical dynamic address may be received by its associated selected receivers, which then modify the dynamic address list. Preferably, after each selected receiver receives a broadcasted information packet, the dynamic address associated with that particular received information packet is removed from the list of dynamic addresses provided to that selected receiver at least temporarily.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to electronic communication systems, particularly to 
such communication systems capable of addressably broadcasting information 
to certain receivers. 
2. Description of the Background Art 
Conventional communication systems are available for broadcasting signals 
from a transmission source over designated channels to various receivers 
listening to such channels. In such broadcasting configuration, however, 
it is sometimes desirable to control which receivers may receive the 
broadcasted information. Thus, so-called "addressable" communication 
systems, such as electronic remote paging systems, are provided which 
enable only addressed receivers to receive the broadcasted information. 
Known addressable communication systems, however, are limited to the extent 
that the addressability of their receivers is not easily reconfigurable, 
particularly once the system has been deployed and also with respect to 
the specific type of information broadcasted. Therefore there is a need 
for addressable communication systems which facilitate dynamic 
reconfiguration of receiver addresses, preferably depending on the 
specific information broadcasted, thereby providing improved spectrum 
efficiency. 
SUMMARY OF THE INVENTION 
In accordance with one embodiment of the present invention, either a list 
or set of dynamic addresses is provided to selected receivers in a 
communication system for addressably broadcasting information packets from 
a transmission source to such selected receivers. Each dynamic address 
provided in the list or set is associated with a particular information 
packet designated to be received by the selected receivers to which that 
dynamic address is provided. Additionally, each broadcasted information 
packet includes at least one dynamic address identical to the dynamic 
address provided to its associated selected receivers. 
Thus, the broadcasted information packet which includes such identical 
dynamic addresses may be received by its associated selected receiver, at 
which time, the associated selected receiver modifies the list or set of 
dynamic addresses. Preferably, after each selected receiver receives a 
broadcasted information packet, the dynamic addresses associated with that 
particular received information packet is removed from the list or set of 
dynamic addresses provided to such selected receiver.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
FIG. 1 shows a block diagram of dynamically-addressable communications 
system 10, including broadcast source or sender 12 for transmitting 
information packet 200 through broadcast channels or network 14 to various 
receiver units 100. System 10 is dynamically-addressable to enable 
different users to receive the same or different information packets and 
to allow reconfiguration of different addresses at different times. 
System controller 13 may cause sender 12 to send, or receive, packets 200 
through channels 14, which may be one or two-way, wired or wireless 
broadcast channels, such as satellite, microwave, telephone, or the like. 
Moreover, packets 200 may be fixed or variable-length, digitally-encoded 
message streams or frames, including digital data and/or analog voice 
information. Thus, communication through channels 14 may comply with 
conventional broadcast communication technology. 
Multiple receiver units 100(1)-(N) communicate through channels 14 to 
receive simultaneously, and optionally send separately in a two-way 
configuration, packets of information to and from sender 12. As shown in 
FIG. 2 in additional detail, each receiver unit 100 includes communication 
controller 110, memory 120, interface 130, and power supply 140. 
Communication controller 110 includes conventional digital communications 
equipment for receiving 111, transmitting 112, decoding 113, and encoding 
114 information signals as packets 200. 
In addition, controller 110 includes conventional analog-to-digital (A/D) 
118 and digital-to-analog (D/A) 119 circuitry for converting certain 
information contained in packets 200 into appropriate form. For example, 
received decoded packet information containing analog voice or music 
signals may be converted to digitized form for proper storage in memory 
120. Controller 110 also includes processor 115, which may be a 
conventional microprocessor or microcontroller for processing information 
within receiver 100. 
Memory 120 includes static 122 and dynamic 124 memory portions. Static 
memory 122 stores static address 123. Preferably, each receiver unit 100 
stores a different static address 123 such that packets 200 destined for 
that particular receiver unit 100 may be addressed uniquely thereto. 
Dynamic memory 124 stores dynamic address list 125 and time and frequency 
"stamp" information 127. 
Furthermore, user interface unit 130 includes microphone, speaker or audio 
interface 132, video display screen or visual interface 134, and switch 
key or keyboard interface 136. Audio interface 132 includes audible (e.g., 
speaker) 132 or visual (e.g., light bulb, LCD or the like) alert device 
134. Keying interface 136 includes manual switch or entry device 137 to 
allow direct user request for information or for requesting for additional 
information. Power supply 140 is provided to provide power to receiver 100 
components. 
In accordance with the present invention, system 10 provides a list or set 
of dynamic addresses 125 to selected receivers 100 for receiving 
broadcasted information packets 200 from transmission source 12, 13 to 
selected receivers 100. Each receiver 100 may also be provided separately 
with unique static address 123. Each dynamic address provided in list 125 
is associated with a particular information packet 200 designated to be 
received by particular selected receiver or receivers 100 to which that 
dynamic address 125 is provided. Additionally, each broadcasted 
information packet 200 includes at least one dynamic address 204, 207 or 
static address 202 which is identical to dynamic address in list 125 or 
static address 123 provided to selected receivers 100. 
Thus, the broadcasted information packet 200 which includes such identical 
dynamic address 125 may be received by its associated selected receivers 
100 and stored for subsequent retrieval, preferably according to 
prioritized storage sequence, in dynamic memory 124, where dynamic address 
list 125 may then be modified. Such storage may occur silently, i.e. 
without alerting the user of receiver 100, or noticeably by triggering 
device 133 to alert such user. 
Preferably, after each selected receiver 100 receives broadcasted 
information packet 200, the dynamic address 125 associated with that 
particular received information packet 200 is removed or deleted by 
processor 115 from the list of dynamic addresses 125 provided to that 
selected receiver 100. Optionally, the removed dynamic addresses are 
stored temporarily, separately from list 125 in dynamic memory 124 in 
receiver 100. 
The temporary storage of previously-removed dynamic addresses enables the 
user of receiver 100 to define or generate, according to a hierarchical 
address algorithm, additional dynamic addresses derived from or related to 
any of the temporarily stored addresses, for addition to and storage in 
list 125. In this way, after a user receives a certain packet 200 having a 
particular dynamic address 125, 204, 207 at which time such dynamic 
address is tentatively removed from list 125, the user may effectively 
request from sender 12 additional information related to such packet 200. 
Requesting additional information is accomplished by including such 
derived or related dynamic address or addresses in list 125. 
Preferably, sender 12 is provided by system controller 13 with the same or 
equivalent algorithm for providing or assembling for transmission 
requested packets 200, such that dynamic addresses of such packets 200 are 
related to or derived from the temporarily stored addresses. For example, 
such requested packets 200 are defined and broadcasted by sender 12 such 
that the dynamic addresses associated with the requested packets are 
configured to be a hierarchical variation of the temporarily stored 
addresses, thereby enabling the user of receiver 100 to request 
effectively by defining different groups or subgroups of additional 
packets. The dynamic address may be iteratively varied by appending an 
incremental index thereto, for indicating sequential request relationship 
or hierarchical information derivation. 
Moreover, users of receiver 100 may acquire or request, possibly by 
purchasing beforehand, list entries for dynamic addresses corresponding 
with "billing" or authorization credits to receive selected groups or 
subgroups of additional packets of information. To this end, such billing 
credits may be included in either initial or subsequent packets. 
Optionally, dynamic address list 125 is provided by broadcast source or 
sender 12 which transmits dynamic address list 125 to receivers 100 over a 
predefined or "stamped" transmission frequency and time period 127, as 
stored previously in dynamic memory 124. The predefined transmission 
frequency and time period 127 are provided to broadcast source 12, by 
receivers 100 in a two-way communication configuration, or by system 
controller 13 in a one-way communication configuration to selected 
receivers. 
At predefined intervals, system controller 13 may cause sender 12 to 
retransmit the same, previously transmitted dynamic address list 125. This 
retransmission ensures proper list reception by receivers 100. To ensure, 
however, that the same list is not received and stored duplicatively, 
receivers 100 store the time stamp information 106 from each received list 
in dynamic memory 124, and receiver processor 115 compare such stored 
information to identify redundant time stamp information. Thus, a 
duplicate list is received when redundant time stamp information is 
identified, and processor 115 causes receiver 100 not to store such 
duplicate list information. 
When system 10 is operating, sender 12 may broadcast or transmit packets 
200 to receiver 100 in one of three transmission modes: (1) Information 
Transmission, (2) Dynamic Address List Transmission, or (3) Download 
Information Transmission. In any mode, receiver 100 may receive 
information "silently," i.e., without alerting its user of incoming or 
received information, per user selection. 
In FIGS. 3A-3C, various forms of information packet 200 are shown, in 
right-to-left transmission direction (i.e., where preamble 201 leads the 
transmitted information stream of each packet,) corresponding respectively 
to the transmission modes of system 10: (1) Information Transmission 
Packet 210, (2) Dynamic Address List Transmission Packet 220, and (3) 
Download Information Transmission Packet 230. 
For each packet type 210, 220, and 230, preamble portion 201 preferably 
includes a toggling binary signal (e.g., . . . 0101010 . . . ) followed by 
an identifiable start-code pattern which serves to begin the digital bit 
stream. Next, for packet types 210 and 220, static address field 202 is 
included in the packet to correspond with information stored in static 
address 123 in memory 120 of receiver 100. In comparison, for packet type 
230, dynamic address field 207 is included corresponding to information 
stored in either static address 123 or dynamic addresses 125. After 
address field 202 or 207, an activation code field 203 is included to 
identify which transmission mode (i.e., (1), (2), or (3)) and packet type 
210, 220, or 230 apply to that packet 200. 
In the case of packet types 210, 230, activation code field 203 is followed 
by fixed or variable-width message field 212, which may include analog 
voice and/or digital data information. Then, for such packet types 210, 
230, an "inverse" activation code field 209 follows message field 212 to 
indicate end of packet. 
When message field 212 is formatted as having a particular fixed width, 
multiple message fields 212 included in different packets 210, 230 may be 
separately received and combined in proper sequence by receiver 100 to 
create or assemble a message stream having a bit width which is wider than 
the particular fixed-width. 
Preferably, processor 115 in receiver 100 monitors incoming packet field 
information to recognize when fixed-width message field 212 is intended to 
be combined with other such fixed-width message fields 212, as may be 
designated by multiple-message flag included in priority field 205 
associated with such received message fields 212. 
Moreover, in the case of packet type 220, activation code field 203 is 
followed by a list, set or series of at least one dynamic address field 
204. Dynamic address fields 204 are followed by prioritization field 205, 
which defines the sequential order by which subsequent message packet or 
field 212 is stored in memory 124 upon receipt of downloaded information 
packet 230. Prioritization field 205 is followed by time stamp field 206, 
which includes time period and frequency information corresponding to time 
period and frequency information 127 stored in dynamic memory 124 in 
receiver 100. 
Finally, time stamp field 206 is followed by "inverse" activation code 
field 209 to indicate end of packet type 220. Note that particular packet 
types 210, 220, or 230 may follow additional packet types serially in 
transmission, as shown. 
In FIG. 4, a flow chart of steps performed generally by receiver unit 100 
for receiving packet 200 is shown. The process flow may be started at step 
301 (packet request), or, more typically, by entering directly at step 302 
(monitor channels), thereby bypassing step 301 which is optional. 
In step 301, a particular receiver 100 may indicate to system controller 
13, in optional two-way communication configuration, that such receiver 
100 requests packet transmission. In this regard, processor 115 in 
communication controller 110 for such receiver 100 causes transmit 112 and 
encode 114 units to send an upstream signal to sender 12, for example, 
requesting packet information by including in such request specific 
dynamic address 125 information associated with the requested information. 
Such requests for information are handled internally in receiver 100 and 
enabled by user entry through keying interface 136 in interface 130. Also, 
information request may be achieved by user through either keypad entry or 
voice recognition at interface 130, if appropriately configured to receive 
such additional information request. 
Preferably, however, step 301 is omitted because receivers 100 do not 
necessarily request packet transmission, but rather react to packets sent 
on a one-way channel. Even without requesting packets at step 301, system 
10 may nonetheless operate by enabling receivers 100 to monitor 
intermittently or continuously various broadcast channels or transmission 
networks 14, through which information packets 200 may be sent from sender 
12. When information packet 200 is so transmitted, receiver 100 receives 
such information packet 200, at least temporarily at step 304, by 
communication controller recognizing preamble 201. At decision step 306, 
forward error correction is performed by processor 115 in communication 
controller 110 on the received information packet 200, such that if error 
correction fails, then the information packet 200 is ignored at step 305 
and channel-monitoring step 302 is repeated. 
Next, at decision step 309, processor 115 reads address field 202 or 207 to 
recognize whether the address contained in that information packet 200 is 
identical to any address in memory 120 of the particular receiver 100 
(i.e., static address 123 or dynamic addresses 125). If such comparison 
does not result in recognizing the same address (i.e., the received packet 
200 is not designated for reception at that receiver 100), then the packet 
200 is ignored at step 307 and channel-monitoring step 302 is repeated. 
Next, at decision step 308, processor 115 reads activation code field 203 
to identify which of the transmission mode (i.e., 1, 2, or 3), and, thus, 
corresponding packet type (i.e., 210, 220, or 230) applicable to the 
received packet 200. Hence, if transmission mode is "1", then Information 
Transmission operational step 310 is performed. In step 310, packet type 
210 is further processed, and the content of message field 212 is 
downloaded by processor 115 at step 311 for storing in dynamic memory 124 
and optional alerting of user. In this way, alert device 133 may be 
activated, in conventional paging operation, and an alert message may be 
generated either visually or audibly, for example, using visual interface 
134 or audio interface 132, to notify user of receiver 100 about incoming 
stored information. Note that in this operational mode, only static 
addresses are included in packet type 210. 
If processor 115 determines from activation code field 203 at decision step 
308 that transmission mode is "2", then Dynamic List Transmission 
operational step 320 is performed. In step 320, packet type 220 is further 
processed, and data or address list information contained in dynamic 
address fields 204 in packet type 220 are stored or downloaded 321, 
"silently," to dynamic addresses 125 in dynamic memory 124 of memory 120 
of those receivers 100 which receive packet 220. Optionally, processor 115 
may dynamically define a modifiable, maximum limit on the size of message 
packets 212 which each receiver 100 may download into dynamic memory 124. 
Additionally in the case of including downloadable "credits" in message 
packets 212, a similar limit on the size and number of such message 
packets 212 may be defined. 
Next, at step 322, prioritization information from priority field 205 is 
read by processor 115 and stored in dynamic memory 124 to prioritize the 
sequential access subsequently of stored information, i.e., by 
prioritizing the sequential memory pointers for accessing message packets 
212. Next, at step 323, time stamp field 206 is stored in dynamic memory 
at information field 127. Preferably, time/frequency information stored in 
field 127 is read by processor 115 to cause power supply 140 to power-on 
and enable the receiver to receive information on an assigned channel 
frequency and at designated packet broadcast periods, even to override 
manual shut-off, thereby saving available power of receiver 100. 
Next, at step 324, processor 115 performs memory checking to determine 
whether any of the dynamic addresses 204 for downloading were previously 
in dynamic memory 124. If so, such redundant dynamic addresses 204 are not 
downloaded and are ignored. 
If processor 115 determines from activation code field 203 at decision step 
308 that transmission mode is "3", then Download Transmission operational 
step 330 is performed. In step 330, packet type 230 is further processed, 
and information contained in message field 212 is stored or downloaded 331 
in dynamic memory 124 of memory 120 in receiving receiver 100, possibly 
silently without alerting the user. Note that dynamic address 125 stored 
in memory 124 refers to corresponding address of packet to be received, 
not necessarily to address in memory where message packet 212 is actually 
stored. 
This downloaded information may be retrieved subsequently, preferably 
according to predefined prioritization stored in dynamic memory 124, by 
the user of receiver 100 for playback through audio or visual interfaces 
132, 134, and either deleted or saved for future retrieval. 
Next, at step 332, processor 115 performs memory checking to determine 
whether dynamic memory 124 is close to capacity for storing additional 
information packet 200 information therein. If so, processor 115 may 
either stop storing such additional information, or store only higher 
priority dynamic addresses 204, according to prioritization field 205, 
until remaining memory is fully utilized. Note that after information is 
successfully downloaded in dynamic memory 124 corresponding to particular 
dynamic address 125, that particular dynamic address is deleted or 
removed, preferably tentatively, by processor 115 from dynamic memory 124, 
at step 333. 
Next, at step 334, the removed dynamic address is temporarily stored 
separately in dynamic memory 124 for possible subsequent use when user of 
receiver 100 effectively issues additional information request, 
particularly when such request derives from or relates to specifically a 
prior information packet 200 having such removed dynamic address. As 
discussed above, such additional information request is accomplished by 
the user requesting additional information, which in turn generates new 
dynamic addresses which are a predefined variant of the removed dynamic 
address to dynamic address list or set 125. It is also contemplated that 
user request of primary information may be accomplished through keypad 
communication. 
At the end of each operational step 310, 320, and 330, inverse activation 
codes 209 are identified by processor 115 respectively at steps 319, 329, 
and 339, to recognize the end of each particular packet type. Finally, 
channel-monitoring step 302 may be repeated.