A method and apparatus for maximizing standby time in remote stations configured to receive broadcast databurst messages

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DESCRIPTION

Method and apparatus for maximizing wait time at remote stations configured to receive broadcast data burst messages.

Background of the invention

I. Field of the invention

The present invention relates to the transmission and reception of broadcast data burst messages within a telecommunications system. More particularly, the present invention relates to a novel and improved method and apparatus for increasing the waiting time of the broadcast data burst message receiver in a wireless telecommunications system.

II. Description of the prior art

The proposed cdma2000 cell phone regulation published by the Telecommunications Industries Association (TIA), entitled “cdma2000 Series TIA / EIA / IS-2000”, published in August 1999, hereinafter referred to as cdma2000 , uses advanced signal processing techniques to provide high-quality and efficient telephone service, and is incorporated herein by reference. For example, a cdma2000-compatible cellular phone system uses decoding, error detection, direct error correction (FER), interleaving, and spread spectrum modulation to make the use of available radio frequency (RF) bandwidth more efficient. efficient, and to provide more robust connections. Overall, the benefits provided by the cdma2000 include longer talk time and fewer dropped calls compared to other types of cell phone systems.

To carry out communications in an orderly manner, the cdma2000 standard provides a set of highly encrypted channels through which data that have different functions is transmitted. These highly scrambled channels include one or more full page channels, to carry page messages that notify cellular phones or other types of wireless terminals, hereinafter referred to as remote stations, that an incoming request is pending. Communication. The full search channel is described further below. Additionally, the cdma2000 provides a channel that is a highly unscrambled channel, the fast paging channel, which is further described below, to extend the remote station standby time. There is currently a new version of cdma2000, often referred to as cdma2000 Version A, which is being put to a vote. The voting version of cdma2000 Version A can be found in the December 1999 versions of the following six TIA documents: PN-4693, PN-4694, PN-4695, PN-4696, PN-4797, and PN-4898. This voted version of cdma2000 Version A is hereinafter referred to as cdma2000A. The cdma2000A introduces the Common Direct Control Channel (FCCCH) and the Direct Broadcast Channel (F-BCCH). While the cdma2000 full page channel uses a full page channel to carry both general page messages (to be described later) and broadcast data burst messages, the cdma2000A uses the F-CCCH to carry the page messages. general search, and uses the F-BCCH to carry broadcast data burst messages. The present invention relates to both cdma2000 systems and cdma2000A systems.

A similar structure of search channels is disclosed in US Publication Nos. 5,481,254 and WO 9854919.

The invention relates to a method according to claim 1, a terminal according to claim 5, a system according to claim 9 and a base station according to claim 13.

Fig. 1 is a block diagram of a simplified cellular telephone system that can be used to implement the present invention. Remote stations such as stations 10 (typically cell phones) are located between base stations 12. The remote stations 10a and 10b are in an active mode and therefore are communicating by interface with one or more base stations 12 using radio frequency (RF) signals modulated in accordance with the CDMA signal processing techniques of the cdma2000 standard. . A system and method for modulating RF signals according to CDMA modulation are described in US Patent No. 5,103,459 entitled "System and Method for Generating Signal Waveforms in a CDMA Cellular Telephone System" assigned to the assignee of the present invention. The other remote stations 10 are in standby mode and are therefore monitoring either a full search channel for search messages indicating a communication request, or they are monitoring a fast search channel for indicator bits indicating if a message is expected on a full search channel. In US Patent Application Serial No. 09 / 252,846, filed February 19, 1999, entitled "A Method And Apparatus For Maximizing Standby Time Using A Quick Paging Channel," which is a partial continuation of US Patent Application Serial No. 08 / 890,355 filed July 9, 1997, entitled "Dual Event Slotted Paging," which is a partial continuation of US Patent Application Serial No. 08 / 865,355 filed May 30, 1997, also of the same title, A quick search channel is provided as an example.

In one of the preferred embodiments, each base station 12 generates forward link signals comprised of a set of forward link channels. Channels are established using a set of Walsh codes

ES 2 323 391 T3 orthogonal. A Walsh code is used to modulate the data associated with a particular channel. The channels are classified according to function and include a pilot channel over which a phase shift pattern is repeatedly transmitted, a synchronization channel through which synchronization data is transmitted including absolute system time and phase shift. associated pilot channel phase, and traffic channels through which data directed to terminals 10 is transmitted. Traffic channels are typically assigned to transmit data to a particular remote station 10 for the duration of the interface with that particular base station. It should be understood that other code types and code lengths may be used in similar systems, along with other control channels.

Additionally, according to one of the embodiments, one or more of the Walsh channels is designated as a fast search channel, and one or more of the Walsh channels is designated as a full search channel. The designation and operation of the full search channel is preferably performed in accordance with the search channel specified by the cdma2000 standard. In US Patent No. 5,392,287 entitled "Apparatus And Method For Reducing Power Consumption In A Mobile Communications Receiver" and US Patent No. 5,509,015 entitled "Method And Apparatus For Scheduling Communications Between Transceivers", both assigned to the assignee of The present invention describes some methods and apparatus for conducting searches substantially in accordance with the cdma2000 standard.

As described in US patents 5,392,287 and US 5,509,015, and as specified by the cdma2000 standard, the full search channel is divided into time slots. The time slots are assigned in groups of remote stations 10. The assignment is made based on the International Mobile Subscriber ID (IMSI) that is unique for each remote station 10, or other terminal identification information such as one or more numbers identification number of mobiles (MIN). In alternative embodiments, other identification information may also be used including the electronic serial number (ESN) of the remote station 10 or the temporary mobile subscriber ID (TMSI). The various types of identifying information that can be used will hereinafter be referred to collectively as Mobile ID. Quick Search channels are also divided into time slots.

In US Patent Application Serial No. 09 / 252,846 filed February 19, 1999, entitled "A Method And Apparatus for Maximizing Standby Time Using A Quick Paging Channel," features of the full search channel are described along with an explanation. detailed channel search quick. The search schemes disclosed in US Patent Application Serial No. 08 / 890,355 filed July 9, 1997, entitled "Dual Event Slotted Paging," and in US Patent Application Serial No. 08 / 865,355 filed May 30, 1997, illustrate the basic implementation of a full paging channel in combination with a fast paging channel to provide terminal paging.

A full page channel is a shared channel, which means that messages transmitted on this channel can be decoded simultaneously by many remote stations. The highly coded full page channel, which is divided into time intervals of a predetermined duration called full page intervals, contains among other messages, page messages to indicate when there is an incoming call for a particular remote station. These page messages can also be used to instruct a remote station to enter a dedicated traffic channel to receive a data burst message directed to it. Data burst messages that are addressed to an individual remote station are referred to hereinafter as point-to-point data burst messages, and are commonly referred to as SMS (short message service) messages. “Joe, I got caught in a meeting. I'll be home 30 minutes late for dinner, ”is an example of the content of the text portion of a point-to-point data burst message.

In an alternative embodiment that follows the techniques of cdma2000A, the previously described page messages are transmitted over the F-CCCH instead of the full page channel.

A fast page channel is a shared channel that indicates to a remote station whether a page for that remote station is about to be transmitted on the page channel. The fast search channel is divided into fast search intervals of a predetermined duration, which are preferably shorter than the duration of the entire search intervals. In an illustrative embodiment, each fast search interval is 80 milliseconds (ms) long, while each full search interval is 1.28 seconds. In the illustrative embodiment, a new full search interval begins every 80 ms. Thus, in any 1.28 second period there are 16 full search intervals that partially overlap each other, and there are 16 fast search intervals that do not overlap each other. In the illustrative embodiment, fast search intervals are associated with full search intervals with the following one-to-one correspondence. Each quick search interval that ends is associated with the next full search interval that begins after its completion.

To help clarify the situation, please see Fig. 2. In Fig. 2, the top row is representative of the fast search intervals, each with an illustrative duration of 80 ms, and in which the Next quick search interval begins immediately after another one ends. The middle row, which may be referred to as the FPA interval cycle, is representative of a set of complete search intervals within illustrative limits of 1.28 seconds. The third row, which can be referred to as a cycle of intervals

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FPB, is representative of another set of full search intervals that repeat at illustrative limits of 1.28 seconds. The timing chart at the bottom shows that:

FPA1 full search interval starts in 0.1 second (100 ms) FPB1 full search interval starts in 0.18 seconds (180 ms) FPA2 full search interval starts in 1.38 seconds (1,380 ms) interval FPB2 full seek interval begins in 1.46 seconds (1,460 ms) FPA3 full seek interval begins in 2.66 seconds (2,660 ms) FPB3 full seek interval begins in 2.74 seconds (2,740 ms)

Fig. 2 also shows the time intervals for various fast searches. In Fig. 2 at point 120, time 0, fast search interval 1 begins at point 122, time 80 ms, fast search interval 1 ends at point 124, time 160 ms, fast search interval 2 ends at point 126, time 240 ms, fast search interval 3 ends at point 130, time 1,360 ms, fast search interval 17 ends at point 132, time 1,440 ms, fast search interval 18 ends at point 140, time 2,640 ms, fast search interval ends33 at point 142, time 2,720 ms, fast search interval ends34

Since fast search interval 1 ends at point 122 (time 80 ms), it is associated with FPA1, the next full search interval that will start after time 80 ms. Similarly, since fast search interval 2 ends at point 124 (time 160 ms), it is associated with full search interval FPB1, the next full search interval that will start after time 160 ms. By the same reasoning, fast search interval 17 is associated with full search interval FPA2, and fast search interval 18 is associated with full search interval FPB2.

As can be seen in Fig. 2, there is a delta time between the end of a fast search interval and the beginning of the full search interval to which it is associated. This delta time exists to allow the remote station time to switch from monitoring the unencoded fast paging channel to monitoring the highly coded full paging channel. In the cdma2000, and in the illustrative embodiment shown in Fig. 2, this delta is 20 ms. However, the delta may have a lower value (as low as a 0 ms delta) or a higher value in alternative embodiments.

Each fast search interval contains indicator bits that are used to indicate to remote stations which remote stations a search will be broadcast for. When an indicator bit is set for a particular remote station in a fast paging interval, subsequently a paging message is transmitted during the full paging interval that is associated with that fast paging interval. For example, referring to Fig. 2, if in fast search interval 2 flag bits were set to indicate that a search was to be sent to a particular remote station 10c (not shown), then a search would be transmitted to the IMSI of remote station 10c during the full search range FPB1.

In an illustrative embodiment, in each 80 ms fast search interval there are 384 bits. Each fast search interval is subdivided into a first 40 ms section and a second 40 ms section, each of 192 bits. In order to achieve redundancy, each bit transmitted as "on" in the first section has a corresponding bit transmitted as "on" in the second section. Similarly, each bit transmitted as "off" in the first section has a corresponding bit transmitted as "off" in the second section. The two corresponding bits will hereinafter be referred to as bit pairs. Every time a remote station is going to monitor a fast search interval, the remote station's hash function will take the system time as one of the inputs, and will generate a representative number of the incoming search bit flag to monitor for the first few 192 bits. The hashing function is also used to determine the other bit of the pair of bits that needs to be monitored in the second group of 192 bits. In other words, each remote station will determine, for each fast paging interval that it monitors, an X bit location, in the first 192 bits, and a Y bit location, in the second 192 bits. The remote station can monitor the X bit and the Y bit over the fast search interval to determine whether or not it should search for an incoming search over the full search channel.

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FIG. 3 is a representation of a two-section interval of an illustrative fast paging channel. In the illustrative embodiment, each slot in a fast paging channel is 80 ms long and is comprised of 384 bits. In the illustrative embodiment, the fast paging channel slots are equally divided into two 40 ms sections, each containing 192 bits. Although the QPS (see diagram) has a value of 384 in the illustrative embodiment, the QPS value as well as the duration of the fast search interval may take other values ​​in illustrative embodiments.

Point 210 is the location of the first bit in the first section of the fast search range. Point 214 is the location of the last bit in the first section of the fast search range. Point 212 is the location of a hashed X bit location, which is located somewhere in the first section of QPS / 2 bits.

Point 220 is the location of the first bit in the second section of the fast search range. Point 224 is the location of the last bit in the second section of the fast search range. Point 222 is the location of a hash Y bit location, which is located somewhere in the second section of QPS / 2 bits. Both X and Y were determined using the same IMSI_S as input, and therefore X and Y constitute a pair of bits of equivalent values. The cdma2000 uses a case of this embodiment, where an 80 ms interval contains 192 bit pairs (QPS = 384). Of the 192 bit pairs, 2 bit pairs, corresponding to the first 2 bits in each 40 ms section, are reserved for future use. The remaining 190 bit pairs correspond to 190 unique hash values, and can be set either on or off to tell remote stations whether or not to monitor a full search channel interval associated with a one channel interval. quick search. Those skilled in the art will appreciate that other embodiments are available, such as embodiments that do not match bits for redundancy, and therefore allow 384 bit locations that are not mutually correlated. Additionally, in alternative embodiments, more or fewer bits could be transmitted in fast paging intervals of various durations.

In describing fast paging intervals and full paging intervals, it should be noted that any given remote station is associated with exactly one full paging interval cycle. A "loop" is a group of full search intervals that begin and end at substantially the same time. For example, referring to Fig. 2, the second row (containing intervals FPA1, FPA2, and FPA3) is a cycle of intervals, while the third row (containing intervals FPB1, FPB2, and FPB3) is another cycle of intervals. These cycles are continuous.

Since a remote station is only associated with one cycle of slots, it is efficient for a base station to only transmit indicator bits for a given remote station in fast paging slots that end exactly before transmission of the full paging slots to the that a remote station is associated. Hence it follows that any given remote station is associated only with fast paging slots that end exactly before the start of each full paging slot in that remote station's slot cycle. For example, referring to Fig. 2, a remote station that is associated with the FPB slot cycle is associated with slots 2, 18, 34, and all other multiples of 2 + 16 * K. Remote stations only need to monitor the quick search intervals to which they are associated.

As embodied in the cdma2000 standard, the base station and remote station use a hashing function to determine which flag bits of the fast paging channel are to be associated with each individual remote station. Each remote station has a unique International Mobile Station Identifier (IMSI) assigned to it, with which it registers with the base stations. The hashing function uses IMSI_S (the abbreviated IMSI, which is the last 10 bits of the IMSI in cdma2000) as one of the inputs, and therefore the hashing function has a single entry for each remote station. In cdma2000, the hashing function also uses system time as input to the hash function. Thus, different indicator bits are set for a particular remote station depending on the transmission time. The receiving remote station can use the same inputs to its hashing function, so that it knows which flag bits to examine in any particular fast seek interval.

By examining the flag bits that the hash function generates, a remote station can tell, by looking at one or more flag bits in the fast search channel, whether or not there will be a message addressed to it in the next interval of the full page channel. As monitoring a small group of one or more flag bits in a fast search channel, which uses a simple modulation on off (OOK), requires much less power than monitoring a multi-bit message in a search channel. highly coded, a remote station can save power when it uses a quick search channel to monitor to find searches. In this way, remote stations can increase their wait time when using a quick search channel to monitor for incoming searches.

Today, a large portion of the data burst messages transmitted in commercial wireless telephone systems are point-to-point data burst messages. As mentioned above, point-to-point data burst messages can be sent to remote stations first by transmitting an incoming page message in order to establish a transmission channel for subsequent transmission of the page burst message. data. In this way, use of the quick search channel can increase the wait time for remote stations configured to receive point-to-point data burst messages.

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The cdma2000 and its predecessors (the Telecommunications Industries Association (TIA) family of protocols known as IS-95, IS-95A, and IS-95B) also support broadcast data burst messages. Broadcast data burst messages, hereinafter referred to as broadcast messages, are data burst messages that are addressed to a group of mobiles. An example of the content of a broadcast data burst message, commonly referred to as a broadcast SMS message by those skilled in the art, is a text message that says “New call forwarding plans available; for more details type * 611 to speak to a customer service representative ”. Although some broadcast messages can be sent to all subscribers, there are also means to send broadcast messages to various groups of remote stations based on the preferences presented by each individual subscriber. The cdma2000 has currently reserved support for 2^Λ16 categories of broadcast messages, of which a small subset has now been defined. These general broadcast categories are described in the document entitled “Short Message Service for Spread Spectrum Systems ANSI / TIA / EIA / IS-637A”, published in September 1999, incorporated herein by reference, in which it is made reference to broadcast categories as service categories.

Remote stations can be configured to receive only broadcast messages from categories in which a particular subscriber is interested. For example, a particular remote station would only receive broadcast messages from the sports category if sports were a broadcast category to which the remote station subscribed. Similarly, a particular remote station would only receive broadcast messages from the local traffic updates category if traffic was a broadcast category to which the remote station subscribed. “TRAFFIC REPORT: detentions on Highway 8 North on Main Street due to an accident. 40 Minute Delays Expected ”is an example of the text of a broadcast message that is only addressed to remote stations that have been configured to receive a category of broadcast messages containing traffic information.

Although the method of monitoring a fast search channel on the cdma2000 allows a remote station to save power when trying to monitor to find a point-to-point data burst message using the fast search channel to monitor to find searches incoming messages addressed to your IMSI, this method does not work for the reception of broadcast messages. The reason it does not work for broadcast messages is that a broadcast message is not directed to a subscriber's remote station, as a point-to-point message does, but is instead directed to all remote stations configured to receive broadcast messages of a particular category. Since there is no correlation between the IMSIs or remote stations and the categories of broadcast messages that they are configured to receive, another method of receiving broadcast messages was developed.

A method of monitoring for the purpose of finding general broadcast messages has now been developed. The method uses the general search message (GPM). In addition to containing incoming page notifications for individual remote stations, a GPM can contain a list of categories of broadcast messages to be transmitted, the channels on which they are to be transmitted, and the time intervals during which each will be transmitted. from them. Each indication of when and on which channel a particular category of broadcast message will be transmitted is hereinafter referred to as a broadcast pointer. In relation to a particular remote station configured to receive a set of one or more categories of broadcast messages, a broadcast pointer of interest is a broadcast pointer that refers to a category in the aforementioned set of categories. A remote station that is configured to receive broadcast messages will periodically monitor transmitted GPM messages at the beginning of their full page intervals. Although the GPM messages are not schematically represented in Fig. 2, in an illustrative embodiment the GPMs are at the beginning of the full search intervals. On the cdma2000A, monitors are performed to find GPM messages within the first 80 ms of each full search interval on the F-CCCH. Due to the methodology the base station uses to transmit GPM, the remote station only needs to monitor for GPM messages during the first 80 ms of the remote station's full search cycle. A remote station may be configured to monitor GPM messages towards the beginning of each full search interval in its interval cycle, or it may be configured to monitor GPM messages at the beginning of one of every N full search intervals. The lower the frequency of monitoring to find GPM with broadcast information, the less power the remote station will consume. The broadcast interval cycle index is a numerical value that corresponds to how often a remote station monitors for GPMs with broadcast information. The higher a remote station's broadcast interval cycle rate, the less frequently a remote station will monitor for GPMs with broadcast information.

In the cdma2000, GPM messages are transmitted on the full page channel, and refer to broadcast messages at a subsequent time interval on the same full page channel. In the cdma2000A, GPM messages are transmitted on an F-CCCH, and refer to broadcast messages in a subsequent time slot on an F-BCCH.

Since many users do not need to receive broadcast messages immediately, remote stations are typically configured with a high broadcast interval cycle rate. In such cases, the remote station does not monitor for GPM with broadcast broadcasts very frequently, thus saving a lot of battery power. In fact, at present, there may be many remote stations

ES 2 323 391 T3 configured not to receive general broadcast messages. However, with the explosion of information, it is believed that new users will begin to demand the reception of broadcast messages of various categories with very little delay. In such a situation, where a user is likely to request a low broadcast interval cycle rate, the power consumption inefficiencies of the above broadcast method scheme will come to light. A method and apparatus are required to maximize the wait time at remote stations configured to receive broadcast data burst messages.

Summary of the invention

The present invention relates to a mobile radio communication system that includes a base station, a plurality of remote stations, a first channel over which general page messages are periodically transmitted containing search information and data burst message references. broadcast, and an auxiliary channel containing broadcast data burst notification indicators. The present invention relates to the use of the auxiliary channel to increase the wait time in remote stations that are configured to receive broadcast data burst messages.

The auxiliary channel in one of the illustrative embodiments is an uncoded modulated on-off (OOK) direct sequence spread spectrum signal that is used by remote stations operating within the station's coverage areas. base.

In an illustrative embodiment, the broadcast data burst notification flags are one or more flag bits set to indicate to a remote station whether it needs to scan the first channel for broadcast data burst message references. general. In an illustrative embodiment, the locations of the flag bits are determined using a hashing function.

In an illustrative embodiment, a fast paging channel is used as the auxiliary channel, in which broadcast data burst notification indicators are multiplexed onto a fast paging channel along with incoming paging notification indicators. In another illustrative embodiment, a new channel is used as the auxiliary channel for the transmission of broadcast data burst notification indicators. In an illustrative embodiment, an F-CCCH is used as the first channel.

In one embodiment of the invention, a method is provided for receiving broadcast messages in a spread spectrum telecommunications system. The method comprises:

associating categories to bit rates of a stream of broadcast indicator bits;

periodically producing triggers to receive one or more bits of the stream of broadcast indicator bits located at said bit indices;

receive said or said bits;

comparing each of said bit or said bits with a value of on or off; and determining, from said comparison, whether or not to subsequently receive and decode an encoded bit stream following said broadcast indicator bit stream in a predetermined time frame.

The stage in which categories are associated may further comprise the stage in which desirable categories of broader messages are hashed through a predetermined hashing function to determine said bit rates.

The stage in which said bit or said bits are received may further comprise the stage in which a spread spectrum signal is demodulated by direct sequence, with on-off modulation, uncoded.

The method may further comprise the step in which one or more incoming search indicator bits are received on the same channel as said or said bits after receiving said or said bits.

The stage in which said bit or bits are received may further comprise the stage in which a first signal is demodulated on a modified fast search channel.

The stage in which one or more incoming search bits are received may further comprise the stage in which a second signal is demodulated on said modified fast search channel after demodulating said first signal.

The stage in which said bit or said bits are received may further comprise the stage in which said or said bits and said search indicator bit (s) are received in an overlay configuration on a modified fast search channel.

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The stage in which said bit or said bits are received may further comprise the stage in which a first signal is demodulated on an auxiliary channel that is orthogonal with respect to a fast search channel.

The method may further comprise: receiving one or more incoming paging indicator bits on a fast paging channel, wherein the stage in which one or more incoming paging indicator bits are received comprises the sub-stage in which a second is demodulated signal on said fast search channel.

In another embodiment of the invention, a method is provided for receiving broadcast messages in a spread spectrum telecommunications system, the method comprising:

associating categories to bit rates of a stream of broadcast indicator bits by hashing desirable categories of broadcast messages through a predetermined hashing function to determine said bit rates;

periodically producing triggers to receive one or more bits of the stream of broadcast indicator bits located at said bit indices;

receive said bit (s) on a modified fast paging channel:

receiving one or more incoming paging indicator bits on said modified fast paging channel; each of said bit (s) and each of said incoming search indicator bit (s) is compared with an on or off value;

determining, from said comparison, whether or not to subsequently receive and decode an encoded bit stream following said broadcast indicator bit stream in a predetermined time frame.

The stage in which said or said bits are received on a modified fast paging channel may further comprise the stage in which an uncoded, onoff modulated, direct sequence spread spectrum signal is demodulated.

In another embodiment of the invention, a method is provided for transmitting broadcast messages in a spread spectrum telecommunications system, the method comprising:

a) determining before the beginning of a first time slot the categories of broadcast messages to be transmitted during said first time slot;

b) determining zero or more bit rates to associate with a stream of broadcast indicator bits of a predetermined length based on said determined categories of broadcast messages from step a);

c) generating said stream of broadcast indicator bits in which bits located in said bit indices are set to a value on, and in which all of the other bits in said stream of broadcast indicator bits are set to an off value;

d) transmitting said stream of broadcast indicator bits on a first channel during a second time interval occurring before said first time interval, wherein said second time interval precedes said first time interval by a default space; Y

e) transmitting during said first time interval an encoded stream of bits containing zero or more broadcast pointers corresponding to said categories of broadcast messages from step a).

The stage in which zero or more bit rates are determined may further comprise the stage in which a hash function is applied to said categories of broadcast messages from stage a) through a predetermined hashing function to determine said zeroes. or more bit rates.

The method may further comprise the step in which a stream of incoming search bits is transmitted on a first channel.

The stage in which an incoming search bit stream is transmitted may further comprise the stage in which said incoming search bit stream is transmitted on said first channel, wherein said first channel is a fast search channel modified.

The stage in which an incoming search bit stream is transmitted may further comprise the stage in which said incoming search bit stream is transmitted on said first channel, wherein said first channel is a fast search channel .

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The stage in which said stream of broadcast indicator bits is transmitted may further comprise the stage in which said stream of broadcast indicator bits is transmitted over a second channel, wherein said second channel is orthogonal with respect to to said first channel.

In another embodiment of the invention, a method is provided for transmitting broadcast messages in a spread spectrum telecommunications system, the method comprising:

a) determining before the beginning of a first time interval the categories of broadcast messages to be transmitted during said first time interval by applying a hash function;

b) determining zero or more bit indexes to associate with a stream of broadcast indicator bits of a predetermined length by applying a hash function to said categories of broadcast messages through a predetermined hashing function;

c) generating said stream of broadcast indicator bits in which bits located in said bit rates are set to a value on, and in which all of the remaining bits in said stream of broadcast indicator bits are set to an off value;

d) generating a stream of incoming search bits;

e) generating a stream of overlay bits by superimposing said stream of broadcast indicator bits on said stream of incoming search bits; and transmitting said stream of overlay bits on a modified fast paging channel during a second time interval that occurs before said first time interval, wherein said second time interval precedes said first time interval by a default space.

In another embodiment of the invention, an apparatus is provided for transmitting a continuous stream of broadcast indicator bits, the apparatus comprising:

a control processor for generating multiple streams of bits to be transmitted wirelessly;

a convolutional encoder for convolutionally encoding bit streams to provide error correction;

a block interleaving module for interleaving bits in a stream of bits provided by said convolutional encoder;

an orthogonal spreading modulation unit for multiplying spreading codes with bit streams received from one or more sources;

a digital modulator for modulating bit streams provided by said orthogonal spread modulation unit;

an rf transmitter for wirelessly transmitting modulated data bits, provided by said digital modulator; a bidirectional bus for coupling said control processor, said block interleaving module, said digital modulator, said orthogonal spread modulation unit, and said convolutional encoder to each other;

a bus for coupling said digital modulator to said rf transmitter; and a control line for coupling said control processor to said rf transmitter.

The control processor can also be used to:

a) determining before the beginning of a first time slot the categories of broadcast messages to be transmitted during said first time slot;

b) determining zero or more bit rates to associate with a stream of broadcast indicator bits of a predetermined length based on said determined categories of broadcast messages from step a);

c) generating said stream of broadcast indicator bits in which bits located in said bit indices are set to a value on, and in which all of the other bits in said stream of broadcast indicator bits are set to an off value;

d) providing said stream of broadcast indicator bits to said orthogonal spreading modulation unit prior to said first time slot.

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In another embodiment of the invention, an apparatus is provided for receiving wireless transmissions, the apparatus comprising:

an rf receiver for receiving wireless transmissions of modulated data bits;

a digital demodulator for demodulating bit streams provided by said rf receiver;

an orthogonal spreading demodulation unit for multiplying spreading modulation codes with bit streams provided by said digital demodulator;

a block deinterleaving module for deinterlacing bits into a continuous stream of bits provided by said orthogonal spreading demodulation unit;

a convolutional decoder for convolutionally decoding bit streams provided by said block deinterleaving module;

a control processor for receiving multiple streams of bits;

a bidirectional bus for coupling said control processor, said block deinterlacing module, said digital demodulator, said orthogonal spreading demodulation unit, and said convolutional decoder to each other;

a bus for coupling said digital modulator to said rf receiver; and a control line for coupling said control processor to said rf receiver.

The control processor can also be used to:

associating categories to bit rates of a stream of broadcast indicator bits by hashing desirable categories of broadcast messages through a predetermined hashing function to determine said bit rates;

producing triggers of said rf receiver periodically to receive one or more bits of the stream of broadcast indicator bits located at said bit indices;

receive said or said bits; comparing each of said bit (s) with an on or off value;

determining from said comparison whether or not to enable said rf receiver and said convolutional decoder to subsequently receive and decode a stream of bits encoded in a first time interval to be used in determining whether or not to receive a broadcast message in a second time interval that occurs after said first time interval.

Brief description of the drawings

The features, objectives, and advantages of the present invention will become more apparent from the detailed description that follows, when considered in conjunction with the drawings, in which like reference characters identify the same shape features. corresponding throughout the document:

Fig. 1 is a block diagram of a cellular telephone system;

Fig. 2 is a timing diagram illustrating slot timing in a fast search channel and a full search channel;

FIG. 3 is a schematic representation of an illustrative embodiment of a two-section fast search range;

Fig. 4 is a schematic representation of N broadcast category indicator bits to be transmitted on an auxiliary channel of the present invention;

FIG. 5 is a schematic representation of a modified fast paging channel slot of the present invention;

FIG. 6 is a basic flow chart of a method used by a base station of the present invention to transmit broadcast category notifications;

Fig. 7 is a basic flow chart of a method used by a remote station of the present invention to receive notifications from the broadcast category;

Fig. 8 is a diagram of the relationship in time and the association between the modified fast search intervals with respect to the GPMs to which they are associated;

FIG. 9 is a diagram of the relationship over time and the association between the conventional fast paging slots and the slots of the new direct broadcast indicator channels of the present invention with respect to the GPMs with which they are associated;

Fig. 10 is a block diagram showing a simplified illustration of a remote station configured in accordance with an embodiment of the present invention; and Fig. 11 is a block diagram showing a simplified illustration of a base station configured in accordance with an embodiment of the present invention.

Detailed description of preferred embodiments

As described above, general page messages are broadcast on highly scrambled channels, and can be used to indicate to remote stations on which channels and in what time slots broadcast messages of particular categories will be transmitted through broadcast pointers. general dissemination. In relation to a particular remote station configured to receive a set of one or more categories of broadcast messages, a broadcast pointer of interest is a broadcast pointer that refers to a category in the aforementioned set of categories. Because broadcast pointers are long, and because broadcast pointers are transmitted over a highly scrambled channel that uses convolutional encoding to ensure integrity, a remote station consumes a considerable amount of power each time it monitors to find a broadcast pointer. of interest. The method of the present invention uses indicator bits on an unencrypted channel in conjunction with broadcast pointers to save power at a remote station.

Fig. 6 is a basic flow chart of a method used by a base station of the present invention to transmit broadcast category notifications. In block 510, a base station determines the categories of broadcast messages to be transmitted in time slots t1 to tX. The process then continues to block 520.

In block 520, the base station supplies the determined categories to a predefined hashing function. The hashing function produces an output that corresponds to one or more bits out of a set of N bits, where N is a default value. In an illustrative form of illustration, N is 8 and the hashing function produces a bit index of a value between 0 and 7. Alternative embodiments could use different values ​​for N. In an illustrative embodiment, only the general broadcast categories are used for the implementation of the hashing function. As is known to those of skill in the art, a hash function such as this can be implemented with a simple query on a table. In an alternative embodiment, the system time is additionally used as input to the hash function. In such an embodiment, the output of the hash function for any given category can produce a different output at two different system times. Next, the process moves to block 530.

At block 530, the base station generates the stream of broadcast indicator bits of the present invention. The stream of broadcast indicator bits is made up of N bits, in which the bits corresponding to the output of the hashing function described in block 520 are set to an "on" value. All other bits in the broadcast indicator bit stream are set to "off". This becomes clearer with an example.

For the purposes of example, it should be assumed that, in a particular illustrative embodiment, the leftmost bit is referred to as bit N-1, the rightmost bit is referred to as bit 0, N is 8, a bit value of 0 means “off”, and a bit value of 1 means “on”. In such a case, a continuous bit stream of the 8 bits 00000000 means that during the time intervals t1 to tX no general broadcast categories will be transmitted. Similarly, a stream of bits of 00001001 means that during the time intervals t1 to tX, categories that with the hash function gave an index value of 0 and categories that with the hash function gave an index value of 3 will be transmitted. .

Although steps 520 and 530 are outlined as separate steps occurring in sequential order, in which all categories are hashed and then all corresponding bits are set, those skilled in the art will appreciate that this is not the case. It is necessary that the stages occur in a mutually exclusive way. For example, in an illustrative embodiment, a category of categories to be transmitted could be hashed, after which the corresponding bit is set in the stream of broadcast indicator bits. A second category of the categories could then be hashed, after which the stream of broadcast indicator bits could be modified to also have the corresponding bit of the last hash function application set.

The process then continues to block 540. At block 540, the broadcast indicator bit stream set in block 530 is transmitted. In an illustrative embodiment, the bit stream is transmitted over an auxiliary channel. which is a direct sequence spread spectrum signal, with modulation

ES 2 323 391 T3 on-off (OOK), unencrypted, used by remote stations operating within the coverage areas of a base station. The base station uses the auxiliary channel to inform remote stations whether or not they should monitor a particular GPM message to find broadcast pointers of certain categories.

Fig. 4 is a diagram of N bits indicating the general broadcast category to be transmitted on an auxiliary channel of the present invention, and they are representative of the continuous stream of bits to be transmitted in block 540. In Fig. 4, the dot 410 is the first bit in the broadcast indicator bit stream. Point 414 is the location of bit N^esimo in the broadcast bit stream. Point 412 is the location of bit X^esimo in the broadcast indicator bit stream, located within the N bits of the bit stream. In an illustrative embodiment, the auxiliary channel and a conventional fast search channel are transmitted at the same time, the auxiliary channel slots being substantially aligned in time with the slots on a conventional fast search channel. In such an embodiment, the bits on the auxiliary channel are transmitted using a different Walsh code with respect to which the bits are transmitted on the fast paging channel.

In another illustrative embodiment, the broadcast indicator bit stream is transmitted in a modified version of a conventional fast paging channel slot. This modified fast paging channel interval is outlined in Fig. 5. While a conventional fast paging channel has intervals of QPS length, and is divided into two sections, as described with reference to Fig. 3, the fast search channel of an illustrative embodiment of the present invention is divided into three sections, as shown in Fig. 5. As shown in Fig. 5, the interval of the fast search channel It is composed of QPS bits, in which the first N bits of the fast paging interval comprise the stream of broadcast indicator bits of the present invention. The second section and the third section of the modified fast search channel contain the incoming search hash bits based on an IMSI_S as is present in the prior art. However, the two hash sections in Fig. 5 differ in length from the prior art. While an existing fast paging channel slot is composed of two QPS / 2-bit sections for incoming page flag bits, the modified fast paging channel slots of the present invention have two (QPS- N) / 2. For example, if a prior art system had a fast search interval of 80 ms, a QPS of 384, in which the incoming search indicator bits were divided into two sections of 192 bits each, then one could creating a modified fast paging channel of the present invention with a value of N = 8, in which the incoming paging indicator bits would be divided into two 188-bit sections. As such, the inbound search hashing function of the modified fast search channel should have an output space that is 4 bits (192-188) smaller than the output space of the prior art hashing function. Although the N bits of the broadcast indicator bit stream are at the beginning of the modified fast paging interval in this illustrative embodiment, the invention in the present case is not limited to such placement. One skilled in the art will appreciate that, in alternative embodiments, the bits may be located in other parts of the modified fast paging channel, such as the last N bits.

In an alternative illustrative embodiment, the stream of broadcast indicator bits is transmitted redundantly for the same reasons that search indicator bits are transmitted redundantly. In one of these illustrative embodiments, each bit of the N bits of the broadcast indicator bit stream is a part of a pair of bits, in which another corresponding bit is set to the same value in the last half of the channel. Quick search modified. A modified fast paging channel of this illustrative embodiment would have N broadcast indicator bits followed by (QPS-2N) / 2 incoming page indicator bits, followed by N redundant broadcast indicator bits followed by (QPS2N) / 2 Redundant Incoming Search Flag bits.

In yet another alternative illustrative embodiment, the broadcast indicator bits may be superimposed on top of the search indicator bits. For example, in the modified fast paging channel, any one bit (or pair of bits in a redundant scenario) that is transmitted as "on" in the overlapping embodiment signals to a remote station that there is either a search. incoming imminent for a remote station that has an IMSI_S that hash this particular bit, or there is an impending broadcast pointer to a category that hash this particular bit.

Fig. 8 is a diagram of the relationship in time and the association between the modified fast paging intervals with respect to the GPMs to which they are associated. In FIG. 8, it is seen that the modified fast paging intervals, including the broadcast bit indicator stream, are associated with GPMs occurring towards the beginning of the next transmitted full paging interval.

In an alternative illustrative embodiment, the fast paging channel of the present invention remains unchanged from the prior art. In this embodiment, the fast paging channel slots are the same as in Fig. 3. In this embodiment of the present invention, the stream of broadcast indicator bits is transmitted on a separate channel, hereinafter referred to as the Broadcast Indicator Direct Channel (F-BICH). The F-BICH uses its own dedicated Walsh code for transmission, and is divided into slots of the same length and duration as the fast paging channel slots. It is necessary to use the first N bits of each slot of the F-BICH to carry the stream of broadcast indicator bits. All the remaining bits can be reserved for future use. Fig. 9 is a diagram of the time relationship and association between the conventional fast paging slots and the new F-BICH slots.

ES 2 323 391 T3 with respect to the GPMs with which they are associated. In Fig. 9, it is seen that the F-BICH slots coincide with the transmission of the fast paging slots. Furthermore, it is noted that the F-BICH slots are associated with the same GPMs as the conventional fast paging slots, namely the GPMs that occur towards the beginning of the next transmitted full paging slot.

Returning to block 540, the process then continues to block 550. In block 550, the base station waits a predetermined amount of time before moving to block 560. The amount of time required is sufficient to allow a remote station to switch. from monitoring the channel that carries the stream of broadcast indicator bits to decoding the messages on the channel that carries the broadcast messages. In an illustrative embodiment, the wait time is 20 ms. However, the waiting time may be longer or shorter in alternative embodiments. The process then moves to block 560.

In block 560 general page messages are transmitted. They are broadcast over a full search channel. In an embodiment corresponding to the cdma2000A, the general page messages are transmitted on the F-CCCH. The general page messages, which contain the broadcast pointers, are transmitted in the same way as in the prior art. It should be noted that the general broadcast categories supplied to the hashing function of block 520 are the same categories that are used to generate the GPM messages in this time interval. In other words, all the categories present in the broadcast pointers of the GPM messages transmitted in block 560 were used as input to the hashing function of block 520. As an example, if a Sports category was referenced in a broadcast pointer found in a GPM message transmitted in block 560, and if a Sports category produces a bit rate of three in the hashing function of block 520, then the stream of broadcast indicator bits in block 540 would have the third bit set to "on". Thus, the stream of broadcast indicator bits in block 540 correlates with the broadcast pointers present in the GPM messages transmitted in block 560.

After block 550, the process moves back to block 510 where the same process is performed for the set of categories to be transmitted in the time intervals t2 to tX + 1.

Fig. 7 is a basic flow diagram of a method used by a remote station of the present invention to receive notifications of broadcast categories. At block 710, a remote station disables a part of its RF unit, since the remote station is currently in an interval suspend mode in which it does not need to enable parts of the RF unit to monitor any of the wireless channels until it elapses. a predetermined amount of time. In some embodiments, other parts of the remote station may also be disabled when the remote station is in an interval sleep mode. The process then moves to block 720.

At block 720, the remote station determines the location of the broadcast indicator bits that it needs to monitor by taking the categories the remote station is configured to receive and using them as input to a hashing function that produces the same output as the hashing function used. by the base station in block 520. Furthermore, in an illustrative embodiment, the remote station also determines the incoming page flag bits that it should monitor. The process then moves to block 730, where the remote station waits until a predetermined time before it needs to enable the RF unit to successfully monitor the aforementioned indicator bits. The process then moves to block 740.

At block 740, the part of the RF unit necessary to monitor flag bits is turned on. Any other part of the remote station that may require to be enabled to process the reception of flag bits is also activated. The process then moves to block 750.

In an illustrative embodiment, the broadcast indicator bit stream is received over a modified version of a conventional fast paging channel slot. This transmission embodiment is described with reference to Fig. 5. In such an embodiment, at block 750 the broadcast flag bits determined at block 720 are selectively monitored from the first N bits of the modified fast paging channel slot. Additionally, if the remote station is monitoring for incoming searches during the current fast paging channel interval, then in block 750 the incoming search indicator bits determined in block 720 are selectively monitored from the bits following the first. N bits of the modified fast search channel interval. In such a case, it should be noted that the inbound search hashing function of the modified quick search channel should have less output than the prior art hashing function. Although the N bits of the broadcast indicator bit stream are at the beginning of the modified fast paging slots in this illustrative embodiment, the invention is not hereby limited to such placement. One skilled in the art will appreciate that the bits can be located in other parts of the modified fast paging channel, such as the last N bits, in alternative embodiments.

In an alternative illustrative embodiment, the stream of broadcast indicator bits is transmitted redundantly for the same reasons that search indicator bits are transmitted redundantly. In one of these illustrative embodiments, each bit of the N bits of the bit stream

ES 2 323 391 T3 broadcast flags is a part of a bit pair, in which there is another corresponding bit set to the same value in the last half of the modified fast paging channel.

In yet another alternative illustrative embodiment, the broadcast indicator bits may be superimposed on top of the search indicator bits. For example, in the modified fast paging channel, any one bit (or pair of bits in a redundant scenario) that is transmitted as "on" in the overlapping embodiment signals to a remote station that there is either a search. incoming imminent for a remote station that has an IMSI_S that hash this particular bit, or there is an impending broadcast pointer to a category that hash this particular bit.

In an alternative illustrative embodiment, the fast paging channel is unchanged, and the broadcast indicator bits are transmitted over the F-BICH of the present invention. This alternative transmission embodiment is also described with reference to Fig. 5. In such an embodiment, in block 750 the broadcast indicator bits determined in block 720 are selectively monitored from the first N bits of the F-BICH interval. Additionally, if the remote station is monitoring for incoming searches during the current fast paging channel interval, then in block 750 the incoming paging indicator bits determined in block 720 are selectively monitored from the fast paging channel interval. conventional.

The process then moves to block 760. In block 760, it is checked if any of the monitored bits were set "on".

If none of the monitored flag bits were set, then the station has communicated to the remote station, with these few bits, that it is not required to monitor the GPMs during the next full search interval. In such a case, the remote station returns to step 710 so that it can quickly return to its interval suspend mode.

In an illustrative embodiment one or more of the monitored flag bits were set to "on", and then the process shifts to block 770. In one embodiment, if a bit is a member of a pair of bits (obtained in view of redundancy in the prior art), it is not monitored as "on" unless the other bit of the pair of bits is also received as "on". At block 770, GPMs are monitored in the same manner as done in the prior art. On the cdma2000, they are monitored on the full search channel. On the cdma2000A, they are monitored on the F-CCCH. The process then moves to block 780.

At block 780, normalized processing is performed depending on the content of the monitored GPMs. Standard processing is performed according to conventional processing based on the reception of GPM messages. For example, if an incoming page is received, the remote station will process it accordingly. In such a case, the processing could involve opening a dedicated communication link with a base station (and subsequently dosing it) before finally reverting to slots suspend mode and returning to block 710. In another example, if a GPM message were received With a broadcast pointer to a message of interest, the remote station would monitor the appropriate channel at the appropriate time based on the content of the broadcast pointer. In another example, the GPM may not contain any messages of interest, and therefore the remote station does not have any standard processing other than the recognition that there are no messages of interest to it.

The process returns to block 710 after completing the normalized processing of block 780.

FIG. 10 is a block diagram showing a simplified illustration of remote station 10 configured in accordance with an embodiment of the invention. The digital demodulator 1012, the Walsh spreading demodulation unit 1013, the block deinterlacing module 1014, the convolutional decoder 1016, and the control processor 1018 are coupled via a digital bus, and the RF receiver 1010 is coupled to the demodulator. digital 1012. During interval sleep mode, control processor 1018 periodically triggers RF receiver 1010 and digital demodulator 1012 to process either a) a modified fast search channel or b) both a conventional fast search channel and an F- BICH, depending on the method of the present invention selected. RF receiver 1010 downstream and digitizes RF signals, and digital demodulator 1012 performs digital demodulation for a first duration, using PN spreading demodulation techniques known in the art. The digitally demodulated data is passed to the Walsh spreading demodulation unit 1013. In an embodiment using a modified fast paging channel of the present invention, the Walsh spreading demodulation unit multiplies the demodulated data by a Walsh code corresponding to the Walsh code of the modified fast paging channel, and provides the output to control process 1018. In an embodiment where a conventional fast paging channel is used in conjunction with an F-BICH of the present invention, the Walsh spreading demodulation unit multiplies the demodulated data by both a fast paging channel Walsh code and by a Walsh code from the FBICH. In such a case, the output of both Walsh output streams is provided to the control processor 1018. In either case, both the broadcast category indicator bits and the search indicator bits are provided to the control processor 1018. Control processor 1018 examines the broadcast indicator bit stream to determine if it needs to monitor GPM for a broadcast pointer of interest. Additionally, the control processor 1018 may monitor the indicator bits for

ES 2 323 391 T3 incoming search to determine if it needs to monitor GPM to find an incoming search. The control system 1018 will decide to monitor GPMs in the next full search interval if the inbound search flag bits or broadcast flag bit stream indicate that it should monitor these GPMs for messages of interest. Additionally, in an illustrative embodiment, if the signal has been received in poor quality, determinable by many conventional methods such as checking the intensity of the pilot signal, the control system 1018 may decide to monitor the GPM regardless of the content of the bit stream.

In the event that the control system 1018 decides to monitor to find these GPMs, it activates the block deinterleaver module 1014 and the 1016 convolutional decoder to begin processing the full search channel (the F-CCCH on the cdma2000A ) for a second duration that is greater than the first duration. The control system 1018 then monitors the data received through the full search channel to find GPM messages that are of interest to it. At this time, the normalized processing of the GPM messages is performed (block 780 of Figure 7). After the normalized message processing has been completed, the control system 1018 deactivates the block deinterleaver module 1014 and the convolutional decoder 1016 and returns to the interval sleep mode. Additionally, in an illustrative embodiment, the RF receiver 1010 synthesizer is also disabled.

One skilled in the art will recognize that control processor 600 can be implemented using field programmable gate arrays (FPGAs), programmable logic devices (PLD), digital signal processors (DSP), one or more microprocessors, integrated circuits of specific application (ASIC) or other device capable of performing the functions described above.

As should be apparent from the description provided above, the present invention allows a remote station 10 to consume less power when monitoring to find broadcast messages during time-out mode when using a continuous stream of bits. indicators of general diffusion. Consuming less power in Interval Suspend Mode allows Remote Station 10 to run longer on battery power and for longer periods of time. thus extends remote station 10 standby time. How remote stations 10 are typically used In mobile telecommunications, it is often necessary to go long periods of time without recharging or replacing the battery in the remote station 10. Therefore, to provide greater convenience, and to reduce the likelihood of lost broadcast messages due to battery depletion, extending the standby time for a given battery size is highly desirable.

FIG. 11 is a block diagram showing a simplified illustration of base station 12 configured in accordance with an embodiment of the invention. The digital modulator 1118, the Walsh spreading demodulation unit 1116, the block deinterlacing module 1114, the convolutional encoder 1112, and the control system 1110 are coupled via a digital bus, and the RF transmitter 1120 is coupled to the modulator. digital 1118.

At an instant in time prior to time slot t1, control processor 1120 determines the categories of broadcast messages to be transmitted in time slots t1 to tX. The control processor 1120 performs a hashing function on these categories, which produces outputs corresponding to one or more bits of a set of N bits, where N is a predetermined value. The control processor 1120 then generates a continuous stream of broadcast indicator bits made up of N bits, in which the bits corresponding to the output of the hashing function are set to an "on" value. All other bits in the broadcast bit stream are set to "off". In an illustrative embodiment, the "on" bits have a value of one while the "off" bits have a value of 0. This continuous stream of indicator bits is supplied to the Walsh spreading modulator 1116.

In an embodiment using a modified fast paging channel of the present invention, the Walsh spread modulation unit 1116 multiplies the supplied bit stream by a Walsh code corresponding to the modified fast paging channel, and provides the same to the 1118 digital modulator.

In an embodiment in which a conventional fast paging channel is used in conjunction with a FBICH of the present invention, the control processor 1120 supplies a continuous stream of pager indicator bits to the Walsh spreading modulation unit 1116. substantially at the same time as providing the broadcast indicator bit stream to the Walsh spreading modulation unit 1116. In such an embodiment, the Walsh spreading modulation unit 1116 multiplies the stream of broadcast indicator bits supplied by a Walsh code corresponding to the F-BICH of the present invention, and multiplies the stream of reporter bits search provided by a Walsh code corresponding to the quick search channel. Next, the Walsh spread modulation unit 1116 combines the two outputs of the independent multiplication operations, and then supplies the combined output to digital modulator 1118. The digital modulator 1118 performs digital modulation on the output of the Walsh spread modulation unit 1116 for a first duration, using PN spreading modulation techniques known in the art, and provides the modulated signal to the RF transmitter 1120, where the signal is converted upstream and transmitted wirelessly.

ES 2 323 391 T3

In one embodiment using a modified fast paging channel of the present invention, the control processor 1110 provides a continuous stream of incoming paging indicator bits to the Walsh spreading modulation unit 1116 after providing the stream. stream of broadcast indicator bits to the spread modulation unit 1116. In such an embodiment, the Walsh spreading modulation unit 1116 multiplies the continuous stream of incoming search indicator bits supplied by a Walsh code corresponding to the modified fast search channel and provides the same to the digital modulator 1118. The digital modulator 1118 performs digital modulation on the output of the Walsh spread modulation unit 1116 for a first duration, using PN spreading modulation techniques known in the art, and provides the modulated signal to the RF transmitter 1120, where the signal is converted upstream and transmitted wirelessly. In this embodiment, the signal flow through the system is such that the transmitted signal is representative of the broadcast indicator bits that are followed by the incoming page indicator bits on the same Walsh channel.

At a subsequent point in time, the control processor 1110 generates general paging messages containing broadcast pointers corresponding to the broadcast categories supplied to the hashing function described above. Broadcast pointers refer to broadcast messages that will subsequently be transmitted between the time slots of t1 and tX. Additionally, the control processor 1110 generates page-in messages corresponding to the previously generated page-in indicator bits. The paging messages are supplied to the convolutional encoder 1112 where they are converted into a convolutionally coded stream of bits to provide error correction. Convolutional encoder 1112 provides the convolutionally coded stream of bits to interleaving module 1114, in which the bits are interleaved or rearranged. The interleaved bit stream is provided to the Walsh spread modulation unit 1116 in which the bit stream is multiplied by a Walsh code corresponding to a full search channel (the F-CCCH in cdma2000), and is provides the 1118 digital modulator. Digital modulator 1118 performs digital modulation on this continuous stream of bits for a second duration, wherein said second duration is greater than said first duration, using PN spreading modulation techniques known in the art. Digital modulator 118 provides the modulated signal to RF transmitter 1120, where the signal is upconverted and transmitted wirelessly.

The methods and techniques disclosed herein can be used in conjunction with various alternative modulation techniques, including TDMA, WCDMA, and EDGE without deviating from the present invention.

The preceding description of the preferred embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined therein can be applied to other embodiments without the use of inventiveness. Therefore, the present invention is not intended to be limited to the embodiments shown herein.