HK1070503B

HK1070503B - Method and system for signaling in broadcast communication system

Info

Publication number: HK1070503B
Application number: HK05102993.8A
Authority: HK
Inventors: R．辛那拉加; J.王; P.E.本德; T.陈; E.G.小蒂德曼
Original assignee: 高通股份有限公司
Priority date: 2001-08-20
Filing date: 2002-08-20
Publication date: 2010-12-17

Description

Method and system for signaling in a broadcast communication system

Background

FIELD

The present invention relates to broadcast communications, also known as point-to-multipoint or group communications, in wired circuit or wireless communication systems. In particular, the present invention relates to a system and method for signaling in such a broadcast communication system.

Background

Communication systems have evolved to allow information signals to be transmitted from an origination station to a physically separate destination station. In transmitting an information signal from an origin station over a communication channel, the information signal is first converted into a form suitable for efficient transmission over the communication channel. The conversion or modulation of the information signal involves varying a parameter of the carrier wave in accordance with the information signal such that the resulting modulated carrier wave spectrum is confined within the communication channel bandwidth. At the destination station, the original information signal is reproduced from the modulated carrier wave received over the communication channel. Such a reproduction is typically obtained using the inverse of the modulation process used at the origination station.

Modulation also facilitates multiple access, i.e., the simultaneous transmission and/or reception of several signals over a common communication channel. Multiple-access communication systems typically include multiple subscriber units that require intermittent service of relatively short duration rather than continuous access to a common communication channel. Several multiple access techniques are known in the art, such as Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), and amplitude modulation multiple Access (AM). Another type of multiple access technique IS the Code Division Multiple Access (CDMA) Spread Spectrum System, which conforms to the "TIA/EIA/IS-95 Mobile Station-Base Station compatibility Standard for Dual-Mode Wide-band Spread Spectrum Cellular System", hereinafter referred to as the IS-95 standard. The use of CDMA techniques IN MULTIPLE ACCESS COMMUNICATION SYSTEMs is described IN U.S. patent No. 4,901,307, entitled "forward speech COMMUNICATION SYSTEM SATELLITE OR TERRESTRIAL REPEATERS," and U.S. patent No. 5,103,459, entitled "SYSTEM AND METHOD FOR GENERATING COMMUNICATION channels IN a CDMA cellular telephone SYSTEM," both of which are assigned to the assignee of the present invention.

Multiple-access communication systems may be wireless or wired and may communicate voice and/or data. An example of a communication system that communicates voice and data IS a system in accordance with the IS-95 standard, which specifies the transmission of voice and data over a communication channel. A METHOD FOR transmitting data in fixed length code channel frames is described in detail in U.S. patent No. 5,504,773, entitled "METHOD AND APPARATUS FOR THE FORMATTING OF data FOR TRANSMISSION," which is assigned to THE assignee OF THE present invention. According to the IS-95 standard, data or speech IS segmented into code channel frames, 20 milliseconds in width and 14.4kbps in data rate. Additional examples of communication systems that communicate voice and data include those that conform to the 3rd generation Partnership Project (3GPP), which IS embodied in a series of files including file numbers 3G TS 25.211, 3G TS 25.212, 3G TS 25.213, and 3GTS 25.214(W-CDMA standard), or the TR-45.5 physical layer standard for CDMA2000 spread spectrum systems (IS-2000 standard).

In a multiple access communication system, communication between users is conducted through one or more base stations. A first user on one wireless subscriber station communicates with a second user on a second wireless communication subscriber station by transmitting data on a reverse link to a base station. A base station receives data and may route the data to another base station. Data is transmitted on the forward link of the same or other base station to a second subscriber station. The forward link refers to transmission from a base station to a wireless subscriber station, and the reverse link refers to transmission from a wireless subscriber station to a base station. Likewise, communication may be between a first user on a wireless subscriber station and a second user on a landline station. The base station receives data on a reverse link from a first user on a wireless subscriber station and routes the data through a Public Switched Telephone Network (PSTN) to a second user on a landline station. In multiple communication systems, such as IS-95, W-CDMA, IS-2000, the forward link and reverse link are assigned to different frequencies.

The above-described wireless communication service is an example of a point-to-point communication service. In contrast, the broadcast service provides a central station-to-multipoint communication service. The basic model of a broadcast system consists of a broadcast network of users served by one or more central stations, which transmit information with a certain content, such as news, movies, sports, etc., to the users. Each broadcast network user's subscriber station monitors a common broadcast forward link signal. Because the central station fixedly determines the content, the user typically does not communicate back. Examples of commonly used broadcast service communication systems are television broadcasts, radio broadcasts, and the like. Such communication systems are typically highly specialized communication systems. With the recent development of wireless cellular telephone systems, point-to-point cellular telephone systems using existing infrastructure, primarily broadcast services, are beginning to be of interest. (the term "cellular" system as used herein includes cellular and PCS frequencies)

The introduction of a common broadcast forward link into a cellular telephone system requires the combination of broadcast services and services provided by the cellular telephone system. A subscriber station needs to be able to support functionality in which the subscriber station can operate in both a broadcast mode and a communication mode. Accordingly, there is a need in the art for a method and system for signaling in a cellular telephone system that provides a broadcast service that allows a subscriber station to complete both services.

Abstract

The embodiments disclosed herein address the above stated needs by providing a method for a subscriber station to register in a broadcast communication system, the method comprising receiving an HSBS channel that modulates a first frequency, monitoring a timer status of the HSBS channel and performing registration with a broadcast service that transmits the HSBS channel if the timer status is expired, setting the timer of the HSBS channel to enabled, and then starting the timer of the HSBS channel. The base station receives a broadcast service registration from a subscriber station of the sector, adds a paging identifier to the user's station paging set, and starts a timer for the paging identifier.

In another aspect, a base station sends a paging message to a subscriber station based on a status of a paging set.

According to another aspect, the above need is met by providing a method for paging a subscriber station in a broadcast communication system that does not require registration by the subscriber station.

Brief Description of Drawings

FIG. 1 illustrates a conceptual block diagram of a high speed broadcast service communication system;

fig. 2 illustrates the concept of physical and logical channels of the HSBS.

Fig. 3 illustrates maintenance of a paging set in accordance with an embodiment.

Description of The Preferred Embodiment

Definition of

The word "exemplary" is used herein to mean "serving as an example, instance, or illustration. Any embodiments described herein are not necessarily to be construed as preferred or advantageous over other embodiments.

The term point-to-point communication is used herein to mean communication between two subscriber stations over a dedicated communication channel.

The terms group service, point-to-multipoint communication, push-to-talk, or dispatch service are used herein to denote a communication in which multiple subscriber stations typically receive a communication from one subscriber station.

The term packet is used herein to mean a group of bits, including data (payload) and control elements, arranged into a particular frame. The control unit includes components such as a preamble, quality metrics and others known to those skilled in the art. Quality metrics include such things as Cyclic Redundancy Check (CRC), parity bits, and other components known to those skilled in the art.

The term access network is used herein to refer to a Base Station (BS) and a collection of controllers for one or more base stations. An access network transports data packets between multiple subscriber stations. The access network may also be connected to additional networks outside the access network, such as a cooperating intranet or the internet, and may transport data packets between each access terminal and such outside networks.

The term base station is used herein to refer to the hardware used by subscriber station communications. A sector refers to either hardware or a geographic coverage area, as determined by the context in which the term is used. A sector is a partition of a sector. The principle described in sectors can be extended to sectors, since sectors have the property of sectors.

The term subscriber station is used herein to mean the hardware with which an access network communicates. A subscriber station may be mobile or stationary. A subscriber station may be any such data device: this data device communicates through a wireless channel or through a wired channel, for example using fiber optic or coaxial cables. A subscriber station may also be any of several devices including, but not limited to: PC card, compact flash, external or internal modem, or wireless or wireline phone. A subscriber base station that is in the process of establishing an active traffic channel connection with a base station is said to be in a connection setup state. A subscriber base station that has established an active traffic channel connection with a base station is called an active subscriber station and is said to be in a traffic state.

The term physical channel is used herein to denote the communication route over which a signal described in terms of modulation and coding features propagates.

The term logical channel is used herein to mean a communication route within a protocol layer within a base station or subscriber station.

The term communication channel/link is used herein to mean a physical channel or a logical channel, chosen specifically according to the context.

The term reverse channel/link is used herein to refer to a communication channel/link through which a subscriber station sends signals to a base station.

A forward channel/link is used herein to mean a communication channel/link over which a base station sends signals to a subscriber station.

The term soft handoff is used herein to mean communication between a subscriber station and two or more sectors, where each sector belongs to a different sector. Reverse link communications are received by two sectors and the forward link is simultaneously on the forward links of two or more sectors.

The term softer handoff is used herein to refer to communication between a subscriber station and two or more sectors, where each sector belongs to the same sector. Reverse link communications are received by two sectors and the forward link is simultaneously conducted on the forward link of one of the two or more sectors.

The term erasure is used herein to mean a failure to recognize information.

Detailed Description

As discussed above, the basic model of a broadcast system includes a user's broadcast network, served by one or more central stations that transmit information to the user with certain content, such as news, movies, sporting events, and the like. Each broadcast network user's subscriber station monitors a common broadcast forward link signal. Fig. 1 illustrates a conceptual block diagram of a communication system 100, communication system 100 being capable of performing High Speed Broadcast Services (HSBS) in accordance with an embodiment of the present invention.

The broadcast content is generated from a Content Server (CS). The content server may be located within a carrier network (not shown) or the external Internet (IP) 104. The content is delivered in packets to a Broadcast Packet Data Serving Node (BPDSN) 106. The term BPSDN is used because although the BPSDN may be physically co-located or similar to a conventional PDSN (not shown), the BPSDN is logically different from a conventional PDSN. The BPDSN106 delivers the packet to a Packet Control Function (PCF)108 according to the packet's destination. The PCF is a control entity that controls the functions of the base station 110 for the HSBS, since the base station controller is used for conventional voice and data services. To illustrate the high level principle of HSBS in conjunction with a physical access network, fig. 1 shows the PCF physically co-located or even identical, but logically distinct from the Base Station Controller (BSC). Those of ordinary skill in the art will appreciate that this is for pedagogical purposes only. BSC/PCF108 provides the packets to base station 110.

Communication system 100 enables High Speed Broadcast Services (HSBS) by introducing a forward broadcast shared channel (F-BSCH)112, where F-BSCH112 supports high data rates for reception by a large number of subscriber stations. The term forward broadcast shared channel is used herein to mean a single forward link physical channel that carries broadcast traffic. A single F-BSCH may carry one or more HSBS channels that are multiplexed in a TDM fashion within the single F-BSCH. The term HSBS channel is used herein to denote a single logical HSBS broadcast session defined by the broadcast content of the session. Each session is defined by broadcast content that changes over time, such as 7 am-news, 8 am-weather, 9 am-movies, and so forth. Fig. 2 illustrates the physical and logical channel principles of the HSBS in question.

As illustrated in fig. 2, the HSBS is provided on two F-BSCHs 202, each F-BSCH202 transmitting on a separate frequency fx, fy. Thus, for example, in the cdma2000 communication system described above, such physical channels may include, for example, a forward supplemental channel (F-SCH), a forward broadcast control channel (F-BCCH), a forward common control channel, other common and dedicated channels, and combinations of channels. The use of public AND private channels FOR the broadcast of information is described in U.S. patent No. 60/279,970 entitled "METHOD AND APPARATUS FOR GROUP usage d edidcated AND COMMON CHANNELS IN WIRELESS network, published 2001, 3/28, assigned to the assignee of the present invention. Those of ordinary skill in the art understand that other communication systems use channels that perform similar functions and therefore the present principles apply to other communication systems. The F-BSCH202 transmits broadcast traffic, which includes one or more broadcast sessions. The F-BSCH202b carries one HSBS channel 204c, and the two HSBS channels 204a, 204b are multiplexed on the F-BCCH202 a. The contents of an HSBS channel are formatted into packets including a payload 206 and header 208.

Those skilled in the art will appreciate that the HSBS broadcast service operation illustrated in fig. 2 is for instructional purposes only. Thus, within a given sector, HSBS broadcast services may be deployed in several ways according to the characteristics supported by the implementation of a particular communication system. Implementation characteristics include, for example, the number of HSBS sessions supported, the number of frequency allocations, the number of broadcast physical channels supported, and other implementation characteristics known to those skilled in the art. Thus, for example, more than two frequencies and F-BSCHs may be used within a sector. Also, more than two HSBS channels may be multiplexed to one F-BSCH. Also, a single HSBS channel may be multiplexed onto more than one broadcast channel within a sector, serving subscribers present in those frequencies on different frequencies.

Because one or more different HSBS channels can be multiplexed onto the same F-BSCH physical channel, the different HSBS channels must be distinguished from each other. Thus, each packet assigned by the base station to a particular HSBS channel has a broadcast service reference identifier (bsrid) that can distinguish one HSBS channel from another. Based on the BSR _ ID value within the received packets, the demultiplexer of the subscriber station distinguishes from each other which packets are to be delivered to the decoder of the monitored HSBS channel. Therefore, the bsrid has radio broadcast validity (i.e., between the subscriber station and the BS).

As discussed above, the HSBS channel represents a single logical HSBS broadcast session defined by the broadcast content of the HSBS channel. Thus, although the BSR _ ID allows the subscriber station to distinguish between physical broadcast transmissions of HSBS channels, the identifier of each logical HSBS channel is required so that the subscriber station can shadow the content of the HSBS channel to the physical broadcast transmissions of the HSBS channel, i.e., the subscriber stations must be distinguished from each other, e.g., movie HSBS is distinguished from news HSBS. Thus, each HSBS channel has a unique identifier (HSBS _ ID) that connects the HSBS content/service subscribed to by the subscriber station and the corresponding physical broadcast transmission. The HSBS _ ID has end-to-end validity (i.e., between subscriber stations and content servers). The HSBS _ ID value is known by external means, i.e. when the subscriber station user subscribes to the broadcast content/service, the subscriber station user needs to obtain the HSBS _ ID corresponding to the HSBS channel. For example, the entire schedule of the game for a particular sporting event is known in advance and advertised, for example, in mass media, service provider campaigns, and the like. News, on the other hand, is broadcast on a periodic schedule. Alternatively, external means include, for example, email, Short Message System (SMS) broadcast, and other means known to those of ordinary skill in the art. In an embodiment, the schedule is provided in an HSBS broadcast session.

Finally, because the HSBS channels are multiplexed on the F-BSCH physical channels, there are multiple possibilities for how to transmit the HSBS channels within the G-BSCH channels, the subscriber station needs to know which HSBS channel (hsbsjd/bsrid) is transmitted on which F-BSCH (fbschjd). This information is specified by a logical to physical mapping. In the described embodiment, the logical-to-physical mapping is completely specified by the set { HSBS _ ID, BSR _ ID, FBSCH _ ID }.

Broadcast service parameter signaling

Because the base station performs logical-to-physical mapping, the logical-to-physical mapping information needs to be signaled over the air to the subscriber station so that the subscriber station that needs to listen to a given HSBS channel can determine which F-BSCH channel it should monitor. Thus, the broadcast physical channel parameters, broadcast logical channel parameters, and logical-to-physical mapping need to be signaled to the subscriber station over the air interface.

In one embodiment, the broadcast service parameters are signaled within overhead messages present on channels provided by the communication system for the overhead messages. However, because the subscriber station used must monitor for overhead messages, even subscriber stations that are not subscribed or do not support HSBS users receive this message and need to decode at least the header of this message. In one embodiment, the header provides information, such as a sequence number that informs the subscriber station whether the message content has changed. All subscriber stations must decode the remainder of the message whenever the message content associated with the overhead parameters changes.

Thus, in another embodiment, the broadcast service parameters are signaled within a broadcast service specific overhead message (BSPM). Only subscriber stations subscribed to or interested in the HSBS service need to monitor this message. Because the subscriber station can start monitoring the HSBS channels at any time, the BSPM needs to be continuously transmitted by each sector, which configures one or more broadcast channels in the frequency of any one sector. According to one embodiment, the BSPM is transmitted on a channel provided by the communication system for additional overhead messages. In a communication system according to the cdma2000 standard, the channels provided by the communication system for overhead messages include, for example, the forward paging channel (F-PCH), the forward broadcast control channel (F-BCCH), and other channels known to those skilled in the art that are provided by communication systems for overhead messages. Those of ordinary skill in the art understand that other communication systems use channels that perform similar functions and therefore the principles apply to other communication systems.

However, the subscriber station can only monitor the channel provided by the communication system for the appended overhead messages while in the idle state. Thus, the subscriber station does not access the BSPM when the subscriber station is engaged in another call, i.e., in a dedicated mode, while monitoring the F-BSCH. Thus, in an embodiment, the broadcast service parameters are signaled to the subscriber station in dedicated mode through messages present on one or more dedicated channels. However, because this embodiment requires that the message be sent once using a dedicated channel rather than on a channel provided by the communication system for overhead messages, the message must be sent separately to each subscriber station. Thus, in an alternative embodiment, the subscriber station continues to use the parameters received within the BSPM while confirming that these parameters may be outdated.

It will be apparent to those of ordinary skill in the art that the BSPM may be used to transmit additional broadcast-related information. For example, the BSPM further includes, for each physical channel, a list of neighbor stations that transmit the same information so that the subscriber station can perform a handover. The handover METHOD and SYSTEM are described IN detail IN co-pending U.S. patent No. XX/XXXXXX entitled "METHOD and SYSTEM FOR a hand off IN a BROADCAST COMMUNICATION SYSTEM," published 8/20/2001. Also, the BSPM may include broadcast service registration related information, as described in detail below. In addition, the BSPM may include HSBS schedule signaling, as described in detail below.

HSBS schedule signaling

Subscriber station users need to know the start time of the HSBS session so that they can monitor the HSBS session. The user also needs to know the duration and end time of the HSBS session. Generally. HSBS channel content schedule signaling is beyond the scope of the air interface/communication system because, as described above, users subscribed to HSBS services may know the schedule of the HSBS broadcast session. However, the user needs convenience without relying on an external method, and can retrieve the HSBS schedule using the subscriber station.

Thus, in one embodiment, the base station notifies the subscriber station of the HSBS session start by messaging on the paging channel. This may be in the form of a broadcast paging message or in the form of a broadcast Short Message System (SMS). This short message indicates the start time of the HSBS session. All subscriber stations listening to the paging channel receive this message and only subscriber stations configured to act on this message inform the subscriber station user of this message. If the subscriber station user chooses to listen to the HSBS session, the subscriber station tunes to the appropriate frequency to monitor the F-BSCH. However, if the subscriber station has been so programmed, it may begin monitoring the F-BSCH without prompting the user.

Since the subscriber station user may decide to listen to the HSBS session at a time later than the session start time, it is not sufficient for the base station to send a message to the subscriber station once just before the session start, since subscriber stations that are not monitoring the paging channel at that time have not received this message. A subscriber station may not monitor the paging channel for a variety of reasons, such as power off, in fading, in a voice call, and others known to those skilled in the art. Therefore, the message needs to be repeated during the entire HSBS session. The more often this message is repeated, the less the average delay for a given subscriber station to join an ongoing session.

In another embodiment, the base station notifies the subscriber station of the start of the HSBS session by messaging on a channel provided by the communication system for additional overhead messages, such as the broadcast service parameters message described above. The information transmitted is the same as that sent on the paging channel, in particular the start time and the duration or end time. However, because the overhead messages are repeated, the information is continuously transmitted. To prevent the user from repeatedly reading the same message (no change in content), a sequence number is added to the overhead message. The subscriber station ignores messages containing the same sequence number. Such use of serial numbers is well known to those skilled in the art. In this embodiment, when using the broadcast service parameters message, the sequence number of the BSPM is incremented only when its content changes, such as when a session starts and when it ends.

The termination of the HSBS session to the user listening to the F-BSCH is indicated by a special termination message sent on the F-BSCH. This requires the multiplex sublayer to know to which frame the broadcast data corresponds and to which frame the signalling data corresponds (end message). In one embodiment, the value of BSR _ ID, e.g., BSR _ ID ═ 000, indicates that the packet carries signaling data. In another embodiment, the base station sends a NULL frame on the F-BSCH without a special message. In yet another embodiment, the base station turns off the F-BSCH. The subscriber station detects that no energy is being transmitted on the F-BSCH and concludes that the HSBS session is over.

Alternatively, each of the above embodiments representing the start of a session may be used to represent the end of a session. In one embodiment, the message content indicating the start of the session includes information of the duration or end of the session. In another embodiment, an explicit message is sent to indicate that the HSBS session is ended.

Because a subscriber station engaged in another call also wishes to monitor the F-BSCH at the same time, the start of an HSBS session must also be signaled to the subscriber station in a dedicated mode. Each of the embodiments corresponding to each of the above-described embodiments in the common mode of operation has equal applicability.

Frequency hashing and paging

When a base station receives a request to communicate with a subscriber station, the base station generates a paging message for the subscriber station. The base station then determines which paging channel the subscriber station monitors and sends a paging message on the paging channel. Because a base station of a communication system may support multiple paging channels per frequency and/or multiple frequencies, a method has been developed to determine at the base station and at the subscriber station which frequency and paging channel the subscriber station monitors. A method based on the cdma2000 standard is described. Those skilled in the art will appreciate that the cdma2000 standard was chosen for instructional purposes and may be replaced by any method that ensures consistency between the base station and the subscriber station.

The subscriber station inputs the system determination sub-state at power up, and selects the system in which to perform the acquisition attempt. In one embodiment, after selecting a system for system determination, the subscriber station transitions to a pilot acquisition sub-state in which the subscriber station attempts to demodulate the pilot signal according to the acquisition parameters retrieved in the system determination sub-state. The subscriber station attempts to acquire a CDMA pilot signal in accordance with the acquisition parameters. When the subscriber station detects that the pilot signal energy is above a predetermined threshold, the subscriber station transitions to a synchronization channel acquisition sub-state and attempts to acquire a synchronization channel. Typically, the synchronization channel broadcast by the base station includes basic system information such as System Identification (SID) and Network Identification (NID), but most importantly provides timing information to the subscriber station. The subscriber station adjusts the station timing of the subscriber according to the synchronization channel information and then enters the subscriber station idle state. The subscriber station begins idle state processing by receiving an additional overhead channel identified in the synchronization channel message, and if the base station acquired by the subscriber station supports multiple frequencies, the subscriber station and the base station use a hash function to determine which frequency to use for communication. The subscriber station and the base station then determine a paging channel that the subscriber station monitors using a hashing function. In one embodiment, the hashing function accepts an entity number to be hashed, such as frequency, paging channel, etc., and an international subscriber station identity (IMSI) and outputs one entity.

The above method (hereinafter referred to as the current hashing method) is very suitable for use in a point-to-point communication system. However, the current hash method cannot be directly applied to a broadcast service, which is explained with reference to fig. 3. Fig. 3 illustrates two HSBS channels 302a, 302b multiplexed on an F-BSCH channel 304a transmitted on frequency fx and one HSBS channel 302c multiplexed on an F-BSCH channel 304b transmitted on frequency fy. There is no HSBS channel on frequency fz. Paging channels 306a, 306b, and 306c are transmitted on frequencies fx, fy, and fz, respectively. Although only one paging channel per frequency is shown in fig. 3, those skilled in the art will appreciate that this is for pedagogical purposes only, as the mapping of the subscriber station on a certain paging channel is determined by a hashing function. If a subscriber station subscribes to all three HSBS channels 302, it will be free to change reception from one HSBS channel 302 to another HSBS channel 302. The term subscription is used herein to mean that a subscriber station is allowed to receive a particular HSBS channel.

Without loss of generality, assume that at time t₁The subscriber station power is increased. For example, using the hashing method described above, the subscriber station tunes toFrequency fz, registers with the base station and begins monitoring the paging channel 306 c. The base station uses the same hashing method to determine that the subscriber station is monitoring the paging channel 306c at frequency fz. At time t₂Subscriber station determination

The HSBS channel 302a is monitored. As explained above, a subscriber station wishing to receive an HSBS channel must monitor a frequency containing F-BSCH channels that are modulated by the HSBS channel. Thus, the subscriber station tunes to frequency fx and begins receiving HSBS channel 302 a. Due to limitations at the subscriber station, which allows the subscriber station to tune to only one frequency, the subscriber station monitors the paging channel 306a at frequency fx. Because the subscriber station needs to be able to receive pages while receiving the HSBS channel, the page message to the subscriber station must be sent on the paging channel at frequency fx. However, the current hashing method does not account for situations where the subscriber station may change frequencies. Thus, hashing the subscriber station on the paging channel 306c at frequency fz the base station is unaware of the subscriber station's retuning. Thus, the paging message sent by the base station on the paging channel 306c at frequency fz will fail. Therefore, there is a need for a method and system to estimate on which frequency a base station pages a subscriber station. Those skilled in the art understand that once the frequency is determined, the current paging channel determination method may be used.

Thus, in accordance with one embodiment of the present invention, subscriber stations register with the base station each subscriber station subscribes to and monitors it for HSBS channel identities of interest. Since each HSBS channel modulates a respective F-BSCH on a certain frequency, the base station knows on which set of frequencies the subscriber station can be found, so that the subscriber station can be successfully paged. Registration using the HSBS channel during handover. The goal of the handoff is to transfer the subscriber station from the HSBS channel transmitted by the first base station to the HSBS channel transmitted by the second base station. However, the HSBS channel may modulate different frequencies at the first and second base stations, but the HSBS has the same unique identifier HSBS _ ID; since each base station knows on which frequency a given HSBS _ ID is transmitted (through logical to physical mapping), the base station can successfully page the subscriber. Therefore, registering the identity of each HSBS channel facilitates handover. According to another embodiment, the subscriber station registers with the base station the modulated frequencies that the user subscribes to and is interested in monitoring the HSBS channel. Registration is performed periodically according to the timer status for a particular HSBS channel.

To enable such registration, subscriber stations subscribe to each subscriber station and are interested in monitoring the HSBS channel (HSBS _ TIMER _ STATUS)_S) The state of the timer is maintained. The HSBS channel is identified by a unique identifier (HSBS _ ID). HSBS _ TIMER _ STATUS of each TIMER_SEither "active" (calculator running) or "time out" (i.e., timer not running). The subscriber station also monitors each HSBS channel (T) that the subscriber station is interested in_HSBS) A counter, the broadcast service registration timer, is maintained. The counter is incremented at predetermined time intervals. When the counter reaches a predetermined value (HSBS _ REG _ TIMER), the subscriber station indicates that the TIMER has expired and will HSBS _ TIMER _ STATUS_SSet to "timeout".

When power is up, the subscriber station initializes the HSBS _ TIMER _ STATUS for all channels_SIs "time out". When a subscriber station tunes to a frequency and registers with the base station that transmitted the frequency according to the current hashing method. If HSBS _ TIMER _ STATUS when the subscriber station tunes to the frequency of HSBS channel modulation identified by HSBS _ ID ═ i_S[i]Set to 'timeout', the subscriber station registers the broadcast service for the HSBS channel with the base station, registers the HSBS _ TIMER _ STATUS_S[i]Set to "active" and start counter T_HSBS[I]. When counter T_HSBS[I]Timeout while the subscriber station is still monitoring the HSBS channel i, the subscriber station registers the broadcast service again with the base station for the HSBS channel, HSBS _ TIMER _ STATUS_S[i]Set to "active" and start counter T_HSBS[I]. When a subscriber station is tuned to a certain frequency (either as a result of an initial power-up registration procedure or as a result of monitoring HSBS channel i) and wishes to monitor HSBS channel j on the same frequency, if HSBS _ TIMER _ STATUS_S[j]Set to 'timeout', the subscriber station registers the broadcast service for the HSBS channel j with the base station, registers HSBS _ TIMER _ STATUS_S[j]Set to "active" and start counter T_HSBS[j]。

Each base station maintains a paging SET (PAGE _ SET) for each subscriber station. Page _ SET of subscriber station when receiving a registration of power increase from the ith subscriber station_jIs initialized to the frequency to which the subscriber station tunes according to the current hashing method, i.e., Page _ SET_j＝{f_POWER-UP}. When a base station receives a broadcast service registration from a subscriber station for an HSBS channel identified by HSBS _ ID ═ i, the base station adds an HSBS channel identifier (HSBS _ ID) to a paging SET PAGE _ SET_j＝{f_POWER-UPI } and starts a counter T_HSBS[I]. If the counter T corresponds to HSBS channel i_HSBS[I]For the subscriber station time out, the base station deletes the HSBS _ ID i from the paging set. When a call arrives for a subscriber station, the base station uses the logical-to-physical mapping to determine one or more frequencies corresponding to all HSBS channels having the identification in the paging set. The base station then sends a paging message to the subscriber station on all of these frequencies. Therefore, the timer of the subscriber station and the timer of the base station must be synchronized or the counter of the base station does not time out before the subscriber station timer times out. If the base station's timer expires before the subscriber station timer expires, the base station deletes the HSBS _ ID i from the paging set and the subscriber station is still on the HSBS channel.

As described above, when the counter T is set_HSBS[I]Registration occurs periodically when a value determined by the value HSBS _ REG _ TIMER is reached, which is a configurable parameter that the base station sends to the subscriber station. The value HSBS REG TIMER is determined as an optimum between the signaling load generated by the subscriber station broadcasting service registration and the signaling load generated by the uncertainty of what frequency the subscriber station needs to be paged. To reduce the signaling load, the broadcast service registration may be combined with another type of registration, such as time-based registration, distance-based registration, area-based registration, and other types of registration known to those skilled in the art. For example, in time-based registration, the base station configures the subscriber station to register at predetermined time intervals. If the subscriber station performs a broadcast service registration, the subscriber station need not perform a time-based registration during that periodInter-registration because the base station determines where the subscriber station is from the broadcast service registration.

Referring again to fig. 3, a method by which a subscriber station and a base station perform in accordance with the above-described embodiments of the present invention is illustrated. At time t₁Subscriber station power up, tuning to frequency fz using the current procedure, setting HSBS _ TIMER _ STATUS for all HSBS channels_SIs "timed out" and registered. The base station initializes the paging set of the subscriber station to frequency fz. (Page _ SET)_i{ fz }). (the pin code i identifies the subscriber station).

At time t₂The subscriber station needs to monitor the HSBS channel 302 a. (HSBS _ ID ═ 1). The subscriber station tunes to frequency fx to send a broadcast wireless service registration for the HSBS channel 302a, setting HSBS _ TIMER _ STATUS_S[1]To "activate", a counter T is then started_HSBS[1]. Base station setting PAGE _ SET_i＝{1，fz}。

At time t₃The subscriber station is no longer interested in monitoring the HSBS channel 302a, but wishes to monitor the HSBS channel 302 b. The subscriber station sends a broadcast service registration for the HSBS channel 302b, setting HSBS _ TIMER _ STATUS_S[2]To "activate", a counter T is then started_HSBS[2]. Base station setting PAGE _ SET_i＝{2，1，fz}。

At time t₄The subscriber station is no longer interested in monitoring the HSBS channel 302b, but wishes to monitor the HSBS channel 302 c. The subscriber station sends a broadcast service registration for the HSBS channel 302c, setting HSBS _ TIMER _ STATUS_S[3]To "activate", a counter T is then started_HSBS[3]. Base station setting PAGE _ SET_i＝{3，2，1，fz}。

At time t₅Counter T_HSBS[1]Timeout, therefore the subscriber station sets HSBS _ TIMER _ STATUS_S[1]Is "time out". Because the subscriber station is no longer monitoring the HSBS channel 302a, the subscriber station does not have to send a broadcast service registration for the HSBS channel 302a, so the base station deletes the HSBS _ ID 1 from the paging set. Thus Page _ SET_i＝{3，2，fz}。

At time t₆Counter T_HSBS[2]Timeout, therefore the subscriber station sets HSBS _ TIMER _ STATUS_S[2]Is "time out". Because the subscriber station is no longer monitoring the HSBS channel 302b, the subscriber station does not have to send a broadcast service registration for the HSBS channel 302b, so the base station deletes the HSBS _ ID 2 from the paging set. Thus Page _ SET_i＝{3，fz}。

At time t₇Counter T_HSBS[3]Timeout, therefore the subscriber station sets HSBS _ TIMER _ STATUS_S[3]Is "time out". Because the subscriber station monitors the HSBS channel 302c, the subscriber station sends a broadcast service registration for the HSBS channel 302c, setting HSBS _ TIMER _ STATUS_S[3]To "activate", a counter T is then started_HSBS[3]. Base station maintains Page _ SET_i＝{3，fz}。

At time t₈The subscriber station is no longer interested in any HSBS channel. In one embodiment, the subscriber station tunes to fz and enters an idle state. Page _ SET_iThere is no change in {3, fz }. In another embodiment, the subscriber station remains on frequency fy.

At time t₉Counter T_HSBS[3]And (6) timing out. According to the present embodiment, in which the subscriber station tunes to fz and enters the idle state, the subscriber station sets the HSBS _ TIMER _ STATUS_S[3]Is "time out". Because the subscriber station is no longer monitoring the HSBS channel 302c, the subscriber station does not have to send a broadcast service registration for the HSBS channel 302c, so the base station deletes the HSBS _ ID 3 from the paging set. Thus Page _ SET_iAnd { fz }. According to the present embodiment, where the subscriber station tunes to fy and enters the idle state, the subscriber station sends a broadcast service registration for the HSBS channel 302c, setting HSBS _ TIMER _ STATUS_S[3]To "activate", the counter T is then restarted_HSBS[3]. Base station maintains Page _ SET_i＝{3，fz}。

In an alternative embodiment, registration is not required. In one embodiment, the HSBS channels are transmitted on all frequencies of a sector. Thus, the current hashing method may be used. In some cases, this embodiment may not be practical because the resource allocation to invoke the F-BSCH on all frequencies is too burdensome. Also, the F-BSCH modulated by the HSBS channel is a high energy channel, so it acts as a kind of interference.

Thus, in another embodiment, the subscriber station initially tunes to a frequency according to the current hashing method, and the base station transmits paging messages on the paging channel for that frequency and the paging channels for all frequencies modulated by the HSBS channel. This embodiment replaces the use of current hashing methods to process simple paging decisions for increased paging load at multiple frequencies and on multiple paging channels without knowing the subscriber station HSBS subscription details.

To reduce paging load, subscriber stations are classified into two categories according to another embodiment. The first category includes subscriber stations that are not subscribed to or do not support HSBS services, and the second category includes subscriber stations that are subscribed to HSBS services. The base station is provided with subscription information for the subscriber station to be paged. The subscriber information is provided, for example, from a Home Location Register (HLR), HSBS content server, or similar entity in the communication system. If there is no HSBS session in progress, all subscriber stations tune to multiple frequencies according to the current hashing method. So that the base station pages the subscriber station on the appropriate frequency and paging channel. When HSBS service starts, subscriber stations of interest to an HSBS session belonging to the second class tune to the appropriate HSBS channel. The base station pages subscriber stations belonging to the first class according to the current hashing method. The base station knows that the HSBS session is on or off and that the subscriber profile of each subscriber station belonging to the second class is known. Thus, the base station sends paging messages to users belonging to the second class on a paging channel on the frequency to which the subscriber station was initially tuned and on a paging channel on the frequency of the HSBS channel modulation to which the subscriber station was subscribed. The present embodiment is directed to the need to know subscriber station subscription information and instead to use a low paging load without modifying the current hashing method.

To prevent uneven distribution of the subscriber station along the frequency due to the subscriber station tuning to different frequencies modulated by the HSBS channel, the above embodiment may be modified by: for subscriber stations belonging to the first class, only the unmodulated frequency of the HSBS is input for the hash function. Also for subscriber stations belonging to the second class, if the HSBS session is in progress, only HSBS modulated frequencies may enter the hash function. Those skilled in the art will appreciate that other combinations of frequencies may be used in accordance with the manner in which the access network is used.

Thus, in another embodiment, the subscriber station notifies the base station as soon as the subscriber station starts or ends monitoring the HSBS channel. Therefore, the subscriber station starts tuning to a frequency according to the existing hashing method. When the subscriber station wishes to monitor an HSBS channel, the subscriber station sends a notification message to the base station indicating that it is desired to monitor the HSBS channel and tune to the frequency of the HSBS channel modulation. When the subscriber station is no longer interested in receiving the HSBS channel, the subscriber station sends a notification message indicating a desire to stop monitoring the HSBS channel and tunes back to the initial frequency. This embodiment assumes a trusted relationship between the subscriber station and the access network. If such a relationship is not established, the base station, upon receipt of the notification message, immediately confirms that the subscriber station subscribes to the requested HSBS channel and either allows or denies the request. Upon receiving the access grant, the subscriber station tunes to the frequency of the HSBS channel modulation. Because the base station is explicitly informed of the frequency to which the subscriber station is currently tuned, it can successfully page the subscriber station. This embodiment replaces the simple paging decision, does not require modification of the current hashing method, does not require knowledge of the subscriber station's subscription and does not eliminate large reverse link signaling loads that are potentially bursty, e.g., at the beginning or end of a typical procedure.

In another embodiment, to reduce the reverse link signaling load, the base station is only notified when the subscriber station changes frequency. Thus, the subscriber station initially tunes to a frequency according to the current hashing method. When the subscriber station wishes to monitor an HSBS channel modulated at a different frequency than the frequency monitored by the subscriber station, the subscriber station sends a notification message to the base station indicating that it is desired to monitor the HSBS channel and then tune to the frequency of the HSBS channel modulation. When the subscriber station is no longer interested in receiving the HSBS channel, the subscriber station no longer continues HSBS monitoring. Because the subscriber station does not change frequency, no action needs to be taken on the part of the subscriber station. Because the base station is explicitly informed about the current frequency to which the subscriber station is tuned, it can successfully page the subscriber station. As in the embodiment described above, a request for a response may be required if a trusted relationship has not been established between the subscriber station and the access network. This embodiment employs a simple paging decision, does not require modification of the current hashing method, does not require knowledge of the subscriber station's subscription and eliminates large reverse link signaling loads that are potentially bursty, e.g., at the beginning or end of a typical procedure.

Those skilled in the art will appreciate that although the flow chart is drawn in order for understanding, certain steps may be performed in parallel in an actual implementation.

Those of skill in the art would understand that information and signals may be represented using any of a variety of different technologies and techniques. For example, related data, instructions, commands, information, signals, bits, characters, and chips may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof throughout the above description.

Those of skill would further appreciate that the various illustrative logical blocks, modules, and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, and such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.

By way of example, implementation or execution of the various illustrative logical blocks, modules, and algorithm steps described in connection with the embodiments described herein may be: a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other programmable logic device, discrete gate or transistor logic, hardware components such as registers and discrete hardware components, or any combination of devices designed to perform the functions described herein. The processor is preferably a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, or multiple microprocessors, one or more microprocessors in conjunction with a DSP core or other such configuration.

The steps of a method or algorithm described in connection with the embodiments disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC (not shown). The ASIC may reside in a user terminal (assuming it was previously broadly defined). In the alternative, the processor and the storage medium may reside as discrete components in a user terminal.

The previous description of the disclosed 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 herein may be applied to other embodiments without the use of the inventive faculty. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

A portion of this disclosure contains material which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the patent and trademark office, but otherwise reserves all copyright rights whatsoever.

Claims

1. A method for subscriber station registration in a broadcast communication system, comprising:

receiving an HSBS channel modulating a first frequency; and

monitoring a timer status of the HSBS channel; and if the timer status is timeout:

registering a broadcast service to a sector transmitting an HSBS channel;

setting a timer status of an HSBS channel to active; and

a timer for the HSBS channel is started.

2. The method of claim 1, wherein said registering for broadcast service to the sector transmitting the HSBS channel comprises:

a paging identifier is sent to the sector.

3. The method of claim 2, wherein said sending a paging identifier to a sector comprises:

an identifier of an HSBS channel monitored by the subscriber station is transmitted to the sector.

4. The method of claim 2, wherein said sending a paging identifier to a sector comprises:

an identifier of a frequency monitored by the subscriber station is sent to the sector.

5. The method of claim 1 further comprising setting the timer status of all HSBS channels to timeout upon a power up of the subscriber station.

6. A method for subscriber station registration in a broadcast communication system, comprising:

receiving a broadcast service registration at a sector from a subscriber station;

adding a paging identifier to a paging set of the subscriber station;

starting a timer for a paging identifier; and

monitoring timer status for all paging identifiers of a paging set for all subscriber stations; and if the timer status of the paging identifier for a subscriber station is expired:

the paging identifier is removed from the subscriber station's paging set.

7. The method of claim 6 further comprising adding a frequency identifier monitored by the subscriber station to a paging set of the subscriber station upon a power rise.

8. The method of claim 6, wherein said adding a paging identifier to a paging set of a subscriber station comprises:

the HSBS channel identifier monitored by the subscriber station is added to the paging set of the subscriber station.

9. The method of claim 6, wherein the adding the identifier to the paging set of the subscriber station comprises:

an identifier of a frequency modulated by an HSBS channel monitored by the subscriber station is added to a paging set of the subscriber station.

10. A method for subscriber station registration in a broadcast communication system, comprising:

determining a state of a paging set of the subscriber station;

determining on which paging channels to page the subscriber station according to the determined states of the paging set of the subscriber station using a hash function; and

paging the subscriber station on all of the determined paging channels.

11. The method of claim 10, wherein the determining the state of the paging set for the subscriber station comprises:

receiving, at a subscriber station, an HSBS channel that modulates a first frequency;

monitoring, at the subscriber station, a timer status of the HSBS channel; and if the timer status is timeout:

registering a broadcast service to a sector transmitting an HSBS channel;

setting a timer status of an HSBS channel to active; and

starting a first timer for an HSBS channel;

receiving a broadcast service registration at the sector from a subscriber station;

adding a paging identifier to the subscriber station's paging set at the sector; and

initiating a second timer for a paging identifier at the sector;

monitoring, at a sector, a timer status of all paging identifiers of a paging set of all subscriber stations; and if the timer status of the paging identifier for a subscriber station is expired:

the paging identifier is removed from the subscriber station's paging set.

12. The method of claim 10, wherein said determining on which paging channels to page the subscriber station according to the determined status of the paging set of the subscriber station comprises:

determining on which frequencies to page the subscriber station according to a paging identifier contained in a paging set of the subscriber station;

determining, for each frequency, on which paging channels to page the subscriber station; and

paging the subscriber station on all of the determined paging channels.

13. The method of claim 10, wherein the determining the state of the paging set for the subscriber station comprises:

sending a first notification from the subscriber station of a desire to receive a broadcast channel;

sending a second notification from the subscriber station that reception of the broadcast channel is desired to stop;

adding a paging identifier to a paging set of the subscriber station upon receiving the first notification;

the paging identifier is deleted from the subscriber station paging set upon receipt of the second notification.

14. The method of claim 13, further comprising:

transmitting a permission to receive a broadcast channel from the sector in response to the first notification; and

the broadcast channel is received at the subscriber station after the grant is received.

15. The method of claim 10, wherein the determining the state of the paging set for the subscriber station comprises:

sending a notification from the subscriber station of a desire to receive a broadcast channel that modulates a second frequency different from the first frequency monitored by the subscriber station;

deleting the identifier of the first frequency from the subscriber station paging set upon receipt of the notification;

an identifier of the first frequency is added to the subscriber station paging set upon receipt of the notification.

16. The method of claim 15, further comprising:

17. A method for paging a subscriber station in a broadcast communication system, comprising:

modulating all frequencies of the sector with a broadcast channel;

determining on which paging channels to page the subscriber station for each frequency using a hash function; and

paging the subscriber station on all of the determined paging channels.

18. A method for paging a subscriber station in a broadcast communication system, comprising:

determining the frequency monitored by the subscriber station when the power rises;

determining all frequencies modulated by the broadcast channel;

paging the subscriber station on all of the determined paging channels.

19. A method for paging a subscriber station in a broadcast communication system, comprising:

determining the frequency monitored by the subscriber station when the power rises; and if at least one broadcast channel is transmitted:

determining all frequencies modulated by at least one broadcast channel subscribed by the subscriber station;

paging the subscriber station on the determined paging channel.

20. The method as recited in claim 19, further comprising:

determining on which paging channel to page the subscriber station for the monitored frequency of the user while the power is increasing; and

if no broadcast channel is transmitted,

paging the subscriber station on all of the determined paging channels.