HK1083287B

HK1083287B - Method and system for a multicast service initiation in a communication system

Info

Publication number: HK1083287B
Application number: HK06103240.6A
Authority: HK
Inventors: R．辛那拉雅; J.王; N．K．N．里昂; 陈道
Original assignee: 高通股份有限公司
Priority date: 2002-07-09
Filing date: 2003-07-09
Publication date: 2010-03-26

Description

Method and system for initiating multicast service in communication system

Technical Field

The present invention relates to multicast communication in a wired or wireless communication system. More particularly, the present invention relates to a method and system for initiating a multicast service in such a communication system.

Background

Communication systems were developed to allow the transmission of information signals from a source station to a physically separate destination station. In transmitting an information signal from a source station over a communication channel, the information signal is first converted into a form suitable for efficient transmission over the communication channel. Conversion, or modulation, of the information signal involves varying the parameters of the carrier wave in accordance with the information signal in such a way that the resulting spectrum of the modulated carrier wave is confined within the bandwidth of the communication channel. At the destination station, the original information signal is reconstructed from the modulated carrier wave received over the communication channel. Generally, this reconstruction is achieved by using the inverse of the modulation process used by the original station.

Modulation may also facilitate multiple access, i.e., simultaneous transmission and/or reception of multiple signals over a common communication channel. Multiple access communication systems typically include a plurality of remote subscriber units that require intermittent access of relatively short duration to a common channel rather than continuous access. Several multiple access techniques are known in the art, such as Time Division Multiple Access (TDMA), and Frequency Division Multiple Access (FDMA). Another type of multiple access technology IS a Code Division Multiple Access (CDMA) spread spectrum system according to the TIA/EIA/IS-95 mobile station-base station compatibility standard for dual-mode wideband spread spectrum cellular systems, hereinafter referred to as the IS-95 standard. The use of CDMA technology IN multiple ACCESS COMMUNICATION SYSTEMs is disclosed IN U.S. patent No. 4,901,307, entitled "forward speech-ACCESS COMMUNICATION SYSTEM USING SATELLITE OR terrestrial transmissions", and U.S. patent No.5,103,459, entitled "SYSTEM AND method propagation method IN a CDMA CELLULAR TELEPHONE SYSTEM", both assigned to the assignee of the present invention.

Multiple-access communication systems may be wireless or wired and may carry voice traffic and/or data traffic. One example of a communication system that carries both voice and data traffic in one system IS the system in accordance with the IS-95 standard, which specifies transmitting voice and data traffic over a communication channel. One METHOD OF transmitting DATA in fixed size code channel frames is described in detail in U.S. Pat. No.5,504,773, entitled "METHOD AND APPARATUS FOR THE FORMATTING OF DATA FOR TRANSMISSION", assigned to THE assignee OF THE present invention. According to the IS-95 standard, data traffic or voice traffic IS divided into 20 microsecond wide coded channel frames at a data rate of 14.4 Kbps. Other communication systems carrying both voice and data traffic include those conforming to the third generation partnership project (3GPP), which IS described in a group of documents including the document nos.3G TS 25.211, 3G TS 25.212, 3G TS 25.213, 3GTS 25.214(W-CDMA Standard), or the TR-45.5 Physical Layer Standard for CDMA2000 Spread Spectrum System (IS-2000 Standard).

In a multiple-access wireless communication system, communication between users is conducted through one or more base stations. The term user refers to both active and inactive entities. A first user on a wireless subscriber station communicates with a second user on a second wireless subscriber station by carrying information signals on a reverse link to a base station. The base station receives the information signal and conveys the information signal on the forward link to the second subscriber station. If the second subscriber station is not within the service range of the base station, the base station routes the data to other base stations, the second subscriber station being within the service range of the base station. The second base station then conveys the information signal on the forward link to the 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. Similarly, 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 from a first user on a wireless subscriber station over a reverse link and routes the data to a second user on a landline station over a Public Switched Telephone Network (PSTN). In many communication systems, for example, IS-95, W-CDMA, IS-2000 forward and reverse links are assigned separate frequencies.

The wireless communication system described above is an example of a point-to-point service where information from a first user is only intended for a second user. In contrast, a multicast service is a service in which the information provided by a source, user or content server is prepared for a subset of all users. The model of the multicast system includes a selected group of users, defined by the user group members. The group members include users of subscriber stations that subscribe to a particular multicast content. For simplicity, the term "member subscriber station" is used to mean "a user on a subscriber station," among other things.

In one such model, member subscriber stations may be provided with information having certain content, e.g., news, movies, sporting events, etc., by one or more content servers through an access network. The term access network is used herein to refer to a base station and a set of one or more base station controllers. Each member subscriber station monitors a forward link channel on which information is communicated. The forward link channel may be shared among the member subscriber stations or may be established between each member subscriber station and a station accessing the network, e.g., a base station serving the member subscriber station. Since the content server fixedly determines the content, the member subscriber stations generally do not communicate back to the access network.

Alternatively, the source of the information is a user who is a member of the selected group; the user provides information to be used for the remaining members of the selected group. If the user wishes to provide information, the user notifies the communication system, for example, by pressing a "push-to-talk" (PTT) button. Typically, user-provided information is routed from the subscriber station to the base station over a dedicated reverse link. The base station then conveys the user-provided information on a multicast forward link. As is the case in point-to-point communication systems, multicast communication systems allow both landline and wireless subscriber stations to access the system. The above-mentioned services are also referred to as group services. Examples of group service communication systems include dispatch services such as local police radio systems, taxi dispatch systems, federal bureau of investigation and confidential services operations, and general military communication systems.

The multicast service communication systems described above are generally highly specialized communication systems. With the recent development of wireless cellular telephone systems, there is interest in using the existing (mostly point-to-point) infrastructure of cellular telephone systems for multicast services. (As used herein, the term "cellular" system includes both cellular and PCS frequencies).

The introduction of multicast systems in cellular telephone systems requires the integration of multicast services with point-to-point services provided by current cellular telephone systems. In particular, both the access network and the subscriber station need to be able to support functionality that allows both multicast mode and point-to-point communication mode. Because point-to-point cellular telephone systems do not support multicast services, there is a need in the art for a method and system for multicast service procedures, and in particular multicast service initiation.

Summary of The Invention

The embodiments disclosed herein address the above stated needs by: determining a multicast group identifier; and including the multicast group identifier in at least one periodically repeated message on the first channel. The subscriber station monitoring periodically repeated messages on the channel; and decoding the periodically repeated message to determine whether a multicast service announcement is included in the periodically repeated message.

Another embodiment meets the above-described need by: determining the identity of subscriber stations belonging to a multicast group; determining a time slot of a channel according to the identity of the subscriber station; and transmitting a multicast service announcement in the time slot on a channel. The subscriber station monitoring the time slot of the channel; and decoding the message communicated in the slot to determine whether a multicast service announcement is included in the message.

Another embodiment meets the above-described need by: including an indicator into a predetermined time slot on a first channel; and including a multicast service announcement into the message communicated in the slot on the second channel, the slot corresponding to a predetermined slot on the first channel if the multicast service announcement is indicated by the indicator. The subscriber station decodes an indicator from a predetermined slot on the first channel and decodes a multicast service announcement in a slot on the second channel, the slot corresponding to the predetermined slot on the first channel if the multicast service announcement is indicated by the indicator.

Another embodiment meets the above-described need by: including an indicator into a first time slot on a first channel; and including a multicast service announcement into a message conveyed in a second slot on the second channel, the slot corresponding to a predetermined slot on the first channel if the multicast service announcement is indicated by the indicator. The subscriber station decoding an indicator from a first time slot on a first channel; and decoding the multicast service announcement in a second slot on the second channel, the first slot corresponding to the first slot if the multicast service announcement is indicated by the indicator.

Another embodiment meets the above-described need by: establishing a link layer protocol between subscriber stations belonging to a multicast group and a multicast service source; and communicating a multicast service announcement over the link layer protocol. The subscriber station participates in the establishment of the link layer protocol; and receiving a multicast service announcement over the link layer protocol.

Brief Description of Drawings

Fig. 1 illustrates a conceptual block diagram of a communication system capable of providing multicast services according to an embodiment of the invention;

FIG. 2 illustrates a message flow according to one embodiment of an advertisement;

FIG. 3 illustrates a conceptual block diagram of a paging message;

FIG. 4 illustrates a message flow according to another embodiment of an advertisement;

FIG. 5 illustrates the relationship between signaling communicated on the forward quick paging channel and signaling communicated on the forward common control channel or the forward paging channel in one embodiment;

FIG. 6 illustrates a message flow according to another embodiment of an advertisement;

FIG. 7 illustrates the relationship between signaling communicated on the forward quick paging channel and signaling communicated on the forward common control channel or the forward paging channel in another embodiment; and

FIG. 8 illustrates a message flow according to another embodiment of an advertisement;

FIG. 9 illustrates a message flow in accordance with another response/channel assignment embodiment;

FIG. 10 illustrates a message flow in accordance with another response/channel assignment embodiment;

FIG. 11 illustrates a message flow in accordance with another response/channel assignment embodiment;

FIG. 12 illustrates a message flow in accordance with another response/channel assignment embodiment;

FIG. 13 illustrates a message flow in accordance with another response/channel assignment embodiment;

FIG. 14 illustrates a message flow in accordance with another response/channel assignment embodiment;

FIG. 15 illustrates a message flow in accordance with another response/channel assignment embodiment;

FIG. 16 illustrates a message flow in accordance with another response/channel assignment embodiment;

FIG. 17 illustrates a message flow in accordance with another response/channel assignment embodiment;

FIG. 18 illustrates a message flow in accordance with another response/channel assignment embodiment;

fig. 19 illustrates a message flow in accordance with another response/channel assignment embodiment.

Detailed Description

Definition of

The term "exemplary" is used herein to mean "serving as an example, instance, or illustration. Any embodiment described herein as "exemplary" is 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 receive communication from typically one subscriber station.

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

The term base station is used herein to refer to the hardware that communicates with a subscriber station. A cell refers to either hardware or a geographic coverage area, the meaning of which term is determined by context. A sector is a portion of a cell. Since a sector has the properties of a cell, the principles described in the term cell can equally be extended to a sector.

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

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

The term logical channel is used herein to mean the routing of communications in the protocol layers of a base station or subscriber station.

The term communication channel/link is used herein to mean either a physical channel or a logical channel, depending on 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.

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

Detailed Description

As described, the model of the multicast system includes a selected group of users, which are defined by members of the user group. The group members include users of subscriber stations that subscribe to a particular multicast content. One or more content servers or other users provide the multicast content. Fig. 1 illustrates a conceptual block diagram of a communication system 100 capable of providing multicast services (also referred to as multicast paging) in accordance with an embodiment of the present invention.

As described, the multicast content may be generated at a Content Server (CS). The content server may be located in the network, CS 1102 (1), or outside the Internet (IP)104, CS 2102 (2). The content may be delivered to the Multicast Packet Data Serving Node (MPDSN)106 in the form of packets. The term MPSDN is used because although an MPDSN may be physically integrated or provide functionality consistent with a common PDSN (not shown), an MPSDN may be logically different from a common PDSN. Depending on the destination of the packet, the MPDSN106 passes the packet to a Packet Control Function (PCF) 108. The PCF is a control entity that controls the functions of the base station 110 for any packet data service, including multicast packet data services, like a base station controller for ordinary voice traffic and data traffic services. To illustrate the high-level conceptual connection between a multicast packet data service and a physical access network, fig. 1 shows that the PCF is physically co-located, but logically distinct from the Base Station Controller (BSC). Those skilled in the art will appreciate that this is for illustrative purposes only. The BSC108 provides the packets to the base station 110. Although the term base station is used, those skilled in the art will recognize that these embodiments are equally applicable to sectors.

Similarly, if the content is generated in CS 1102 (1), the content may be delivered to the Public Switched Telephone Network (PSTN) 112. The PSTN 112 delivers the content to the base station controller BSC108, according to its destination. The BSC108 provides the content to the base station 110.

In another embodiment, the content generated in CS 1102 (1) may be delivered to PSTN 112 in the form of packets through interworking function 120. The PSTN 112 delivers the content to the base station controller BSC108, according to its destination. The BSC108 provides the content to the base station 110.

The base station 110 provides content to the member subscriber stations on the forward channel 114. As discussed, the forward channel may be shared among the member subscriber stations or established between each member subscriber station and the base station serving the member subscriber station. The use of a shared forward link is disclosed IN co-pending U.S. patent application Ser. No.10/113,257, entitled "METHOD AND APPARATUS FOR POINT-TO-MULTIPOINTSERVICE PROVIDED IN COMMUNICATION SYSTEMS", filed on 3/28/2002. The use of public AND private channels FOR information broadcast is disclosed in co-pending U.S. patent application Ser. No.10/113,098 entitled "METHOD AND APPATUS FOR CHANNEL MANAGEMENT FOR PROPOINT-TO-MULTIPOINT SERVICE IN A COMMUNICATION SYSTEMS", filed 3/28/2002, which is assigned TO the assignee of the present application. However, those skilled in the art will appreciate that the cited application is for illustrative purposes only and that other communication systems use channels to perform similar functions and, therefore, the principles may be applied to other communication systems.

Alternatively, a member subscriber station, e.g., member subscriber station 116(1), may transmit multicast content to other member subscriber stations, e.g., member subscriber station 116(2), via an access network. Member subscriber station 116(1) sends multicast content to the group on a reverse link channel 118 assigned to that subscriber station 116(1) by the access network. Reverse link channel assignments are well known in the art, for example, in the above-mentioned application serial numbers 10/113,257 and 10/112,098. Base station 110(1) routes the received information to base station 110(2), and base station 110(2) then transmits the routed information on forward channel 114(2) to member subscriber stations 116 (2).

When multicast services are to be provided, a procedure that enables multicast paging initiation must be followed. The process can be divided into several stages. In the first phase, the member subscriber stations to be provided with the multicast service must be notified. In the next (optional) phase, the interested member subscriber stations respond to the announcement. During the next phase, the channel for delivering the content is selected and allocated.

Notification of multicast paging start

As discussed above, when a multicast page is initiated, subscriber stations that are members of the multicast group must be notified.

In one embodiment, the access network initiates a multicast page by broadcasting notification information to subscriber stations via periodically transmitted messages, such as overhead messages. The term overhead message is used herein to denote a message pertaining to a system parameter, periodically transmitted by each sector. An overhead message containing a multicast paging announcement is transmitted by a sector whose coverage area includes member subscriber stations on a forward link monitored by all subscriber stations not participating in another page. An example of such an arrangement IS an overhead message transmitted on a forward paging channel (F-PCH) or a forward broadcast control channel (F-BCCH) in a communication system according to the IS-2000 standard.

The multicast page is advertised by including an identifier (GROUP _ ID) of the multicast GROUP whose member subscriber stations are desired in the overhead message. If more than one multicast page is initiated, the overhead message contains the identifiers of all multicast groups that are desired for the multicast page. The identifier may be sent in one overhead message, several overhead messages, or all overhead messages included during the multicast paging duration. The last option allows the subscriber station to join the multicast page that is already in preparation. If the identifier is included in the overhead message during the multicast paging duration, the particular multicast group identifier is removed from the message when the multicast paging for the particular multicast group ends. In addition to the identifier, the overhead message may provide other information related to advertising the multicast page, such as the type of traffic channel assignment, the type of bearer transmission used, and other related information known to those skilled in the art. Of course, the remainder of the overhead message includes system-related information as discussed above.

An example of a message flow according to the above-described embodiment is illustrated in fig. 2. At time t₁The sector S receives an indication GROUP IDx,to indicate that a multicast page to be sent to the GROUP with the identifier GROUP _ IDx is to be initiated. The indication may be provided by other entities of the communication system, e.g. a base station controller, a PSTN, an information source (not shown), other entities. Alternatively, the sector S receives the identities of the subscriber stations MS _1 and MS _ 2. The sector S then determines whether the identifier of the multicast GROUP _ IDx includes the subscriber stations MS _1 and MS _2, e.g., by querying a database. As discussed, the information source may include, for example, a server, other subscriber stations, or any other source known to those skilled in the art. Sector S includes an identifier in the overhead message, which in one embodiment includes a broadcast system parameter message BSPM (GROUP _ IDx) and at time t₂The BSPM (GROUP _ IDx) is broadcast. Subscriber stations MS _1 and MS _2 are members of a GROUP with an identifier and receive the BSPM (GROUP _ IDx) and take appropriate action, such as initiating monitoring of the physical channel on which the identified multicast page is to be transmitted, transmitting a response to the access network, notifying the user, and other actions as designed by the particular communication system. Fig. 2 illustrates an embodiment in which an identifier is included in an overhead message during a multicast page. Since the overhead message BSPM is repeated periodically, this identifier is similarly transmitted in the next instance of the overhead message BSPM. At time t₃Only one example is shown.

At time t₄The sector S receives an indication GROUP _ IDy from an information source (not shown) to indicate that a multicast page sent to the GROUP with the identifier GROUP _ IDy is to be initiated. Sector S includes this identifier in an overhead message such as BSPM. Since there are two GROUPs that need to be notified about this multicast page, the broadcasted overhead message transmitted at time t5 contains two identifiers BSPM (GROUP _ IDx, GROUP _ IDy). The subscriber station MS _3 is a member of the GROUP having the identifier GROUP _ IDy, receives the overhead message BSPM (GROUP _ IDx, GROUP _ IDy) and takes the appropriate action as described above.

At time t₆The sector S receives an indication GROUP _ IDx ends from an information source (not shown) to indicate that the multicast page sent to the GROUP with the identifier GROUP _ IDx is to be terminated. Sector areaS removes the identifier from the overhead message, such as the BSPM, and at time t₇An overhead message containing only the identifier GROUP _ IDy, BSPM (GROUP _ IDy) is broadcast. Subscriber stations MS _1 and MS _2 are GROUPs with an identifier GROUP _ IDx, receive the overhead message BSPM (GROUP _ IDy), and take appropriate action, e.g., terminate monitoring the physical channel that is transmitting the multicast page corresponding to the identifier GROUP _ IDy. Multicast paging BSPM (GROUP _ IDy) is not affected and will continue until terminated. After termination, the identifier GROUP _ IDy is removed from the BSPM.

Since the broadcast information is repeated periodically, the subscriber station may join the page at any time after the page begins. To prevent the broadcast message from affecting the paging channel capacity, it is desirable to limit the length of the broadcast message. Therefore, the number of groups that can be included in the broadcast message is limited. In addition, since the broadcast message changes with the start and termination of each page, the subscriber station must monitor each update of the broadcast message. In another embodiment, subscriber stations that are each a member of a multicast group are notified of the start of a multicast page by addressing individual messages sent to the subscriber stations. In one embodiment, the individual messages include an individual multicast page (MCP). The concept of individual MCPs IS explained in the context of a communication system according to the IS-2000 standard. As conceptually illustrated in fig. 3, a paging message 300 may carry a number of pages 302, each ready to be sent to a different subscriber station or group of subscriber stations. Paging message 300 may include, for example, a General Paging Message (GPM) or a Universal Paging Message (UPM), as the GPM or UPM may carry different paging record types. Paging messages are conveyed on the F-PCH or forward common control channel (F-CCCH). The individual pages 302 carried in the paging message are referred to as paging record types, each paging record type including the address 306 of the target subscriber station, the type 308 of page (i.e., individual or broadcast), the content 310 (i.e., service option of page), and other information, such as the sequence number 304. Addressing is specified in a paging address TYPE (ADDR _ TYPE), e.g., Temporary Mobile Station Identifier (TMSI), International Mobile Station Identifier (IMSI), for individually addressing a subscriber station, or an address TYPE for addressing all subscriber stations. Upon receiving the paging message 300, the subscriber station decodes the address 306 to determine whether the page 302 is ready to be sent to the subscriber station. If the address 306 indicates that the page 302 is ready to be sent to the subscriber station, the subscriber station decodes the type 308 to determine the type of page and decodes the content 310 to determine the details of the page. Each type of page, i.e., voice page, data page, and S033 page in a point-to-point communication system, has a corresponding page record. Since multicast paging is a new paging type as discussed, individual MCPs must be defined as new paging record types.

The multicast page is advertised by including a multicast GROUP (GROUP _ ID) into an individual MCP. The individual MCPs are included in the paging message and transmitted to the member subscriber stations using the specific addresses of the member subscriber stations on a forward channel, e.g., F-PCH or F-CCCH. In addition, the MCP may provide further information related to the advertised page, such as the type of traffic channel assignment, the type of bearer transmission used, and other related information known to those skilled in the art.

An example of a message flow according to the above described embodiment is illustrated in fig. 4. At time t₁The sector S receives an indication GROUP _ IDx to indicate that a multicast page sent to the GROUP with the identifier GROUP _ IDx is to be initiated. The indicator may be provided by other entities of the communication system, e.g. a base station controller, a PSTN, an information source (not shown), other entities. The sector S then determines the identity of the subscriber stations MS _1 and MS _2, e.g. by querying a database. Alternatively, the sector S receives the identities of the subscriber stations MS _1 and MS _ 2. The sector S then creates an individual MCP containing the identifier GROUP IDx for the subscriber stations MS _1 and MS _ 2.

Those skilled in the art will appreciate that the paging channel may operate in either a slotted or non-slotted paging mode, as such modes have been described in documents well known to those skilled in the art. By way of example, this mode IS described IN the IS-95 standard, U.S. Pat. No.5,392,287, entitled "METHOD AND DAPPARATUS FOR REDUCING POWER CONSUMPTION IN A MOBILE COMMUNICATION RECEIVER", published on 21.2.1995, assigned to the assignee of the present application. For purposes of illustration, FIG. 4 illustrates a configured communication system in which a subscriber station monitors the F-PCH or F-CCCH in a slotted mode; however, those skilled in the art will appreciate that non-slotted mode may also be used. As will be appreciated by those skilled in the art, the term slot refers to a portion of a physical channel whose length is expressed in time, number of chips, or other suitable units.

Sector S waits until time t₂Waiting paging slots are allocated to the subscriber station MS _1, followed by delivery of individual MCPs for MS _1 as part of a paging message, e.g., GPM, as shown. Subscriber station MS _1 may take appropriate actions such as begin monitoring a physical channel on which to prepare a multicast page to be transmitted corresponding to identifier GROOP _ IDx, transmit a response, notify the user, and other actions as per the particular communication system design. Sector S then waits until time t₃Waiting paging slots are allocated to the subscriber station MS _2 and then individual MCPs are delivered for MS _2 as part of a paging message, e.g., GPM, as shown. The subscriber station MS _2 may take appropriate action as described above. In another embodiment, each member subscriber station is notified of the start of the multicast page by a common channel message addressed to subscriber stations belonging to the group. In one embodiment, the common message comprises a common multicast page (MCP). As explained previously, because the common MCP is ready to be sent to multiple, but not all, subscriber stations, and because the multicast page is a new type of page, the common MCP must be defined as a new page record type. Referring to the structure of paging message 300 shown in fig. 3, new paging record type 302 includes a new paging ADDRESS, a multicast ADDRESS (MC _ ADDRESS)304, which specifies that paging record type 302 is ready to be sent to multiple subscriber stations, and type 308, content 310, and other information, such as sequence number 304.

The start of a new multicast page is advertised by including an identifier of a multicast paging GROUP _ ID into the MCPs of member subscriber stations belonging to the multicast GROUP identified by the GROUP _ ID. The common MCP is included in a paging message and transmitted to a desired subscriber station of the common MCP using MC _ ADDRESS on a forward channel, e.g., F-PCH or F-CCCH. In addition, the MCP may provide other information related to the advertised page, such as the type of traffic channel assignment, the type of bearer transmission used, and other related information known to those skilled in the art. However, as explained above, in current communication systems, a subscriber station is assigned to monitor a paging channel slot in which a page for the subscriber station is to be sent. However, the subscriber stations belonging to the GROUP identified by the GROUP _ ID need not be allocated the same slot on the paging channel. Furthermore, the entity that can respond to the page, such as a Base Station Controller (BSC), may not know which subscriber station is a member of a particular multicast group, and therefore, the BSC cannot perform mapping between individual subscriber stations and the MC _ ADDRESS. This may occur, for example, when multicast services are provided over Internet Protocol (IP) because MCP is triggered upon receiving an IP packet over a multicast IP address. Therefore, a method is required that allows for efficient delivery of multicast paging initiation information. Thus, according to one embodiment, the common MCP is transmitted in the first slot of the Broadcast Paging Cycle (BPC). The concept of BPC IS explained in the form of a paging channel implemented in a communication system according to the IS-2000 standard. As illustrated in fig. 5, the F-PCH and F-CCCH are divided into time slots. To allow periodic broadcast paging, a broadcast paging cycle is defined in the form of a duration (number of slots of F-PCH/F-CCCH), given as follows:

BPC＝B+X (1)

wherein B is given as follows:

B＝2ⁱx16, where 1 ≦ i ≦ 7 for F-PCH and 2 ≦ i ≦ 8 for F-CCCH. (2)

X is a fixed offset. For example in a communication system according to the IS-2000 standard, the value on F-PCH IS 3 and the value on F-CCCH IS 7.

The value of the broadcast INDEX i (BCAST _ INDEX) is sent by the sector in an Extended System Parameter Message (ESPM) for F-PCH and in a multi-carrier radio resource parameter Message (MCRR) for F-CCCH.

A subscriber station in slotted mode monitors a slot and is determined according to the following equation:

B＝2^jx16, where j is 1 ≦ j ≦ 7 for F-PCH and j is 2 ≦ 8 for F-CCCH. (3)

Wherein the value of the slot INDEX j (BCAST _ INDEX) is sent by the sector in an Extended System Parameter Message (ESPM) for F-PCH and in a multi-carrier radio resource parameter Message (MCRR) for F-CCCH.

Thus, for any combination of broadcast index i and slot index j, there will be a conflict between the broadcast slot that the subscriber station monitors for broadcast according to equation (2) and the slot that is monitored by the subscriber station in slotted mode by the individual addressing message according to equation (3). Collisions will repeat within the same time slot; therefore, subscriber stations monitoring a particular slot always need to face a conflict between multicast paging and individual paging. The introduction of the offset X in equation (2) resulting in equation (1) does not completely eliminate the collision, but prevents the collision from occurring periodically in the same time slot, and thus the collision spreads among all subscriber stations. Thus, each subscriber station may decode messages in slots that are not affected.

The first slot of each BPC is an F-PCH/F-CCCH slot for which the following equation holds:

t/4mod(BPC)＝t/4mod(BPC+X)＝0， (3)

where t represents the system time in frames; and

mod denotes the modulo algorithm.

Such an arrangement requires that each subscriber station be woken up and need monitor not only the time slots individually assigned to the mobile station for other types of messages, but also each first time slot of the BPC of the F-PCH/F-CCCH, thus increasing power consumption. To avoid such power consumption, the time slot of the forward quick paging channel (F-QPCH) containing the Broadcast Indicator (BI) bit, associated with the F-PCH/F-CCCH, is used to inform the subscriber station to monitor the F-QPCH for the occurrence or non-occurrence of MCP on the first time slot of BPC of the corresponding F-PCH/F-CCCH. If there is a common MCP ON the first slot of the BPC of the F-PCH/F-CCCH, the BI bit of the corresponding F-QPCH slot is set to ON, causing the subscriber station to start monitoring the first slot of the BPC ON the F-PCH/F-CCCH. Although the subscriber station requires the BI bit of the first F-QPCH slot to be woken up and monitor the BPC, battery loss occurs because the duration of the BI is shorter than the duration of the F-PCH/F-CCCH slot, and the wake-up interval is also shorter.

One disadvantage of the above-described embodiment is that since all MCPs for multicast pages are transmitted ON the first slot of BPC ON F-PCH/F-CCCH, the BI bit ON the corresponding F-QPCH is set to ON when an MCP is present. Thus, each subscriber station monitoring the BI indicator must be awake and monitor the first time slot on the F-PCH/F-CCCH to determine if the MCP is ready to be sent to the subscriber station. Therefore, subscriber stations not belonging to the multicast group to which the MCP is ready to transmit still increase power consumption. As illustrated in FIG. 5, a GPM includes a header for subscriber stations MS belonging to a multicast group (GC _1)₁And MS₂Is transmitted in the first Slot (Slot 0_ p) of the BPC on the F-PCH/F-CCCH. However, since the BI bits in the corresponding Slot (Slot 0_ q) ON the F-QPCH are set to ON, all subscriber stations MS₁-MS₄Must be woken up and monitor Slot 0_ p of the F-PCH/F-CCCH. Similarly, a GPM includes a subscriber station MS for belonging to a multicast group (GC _2)₃Is transmitted in the first Slot (Slot 4_ p) of the next BPC of the F-PCH/F-CCCH. Thus, the BI bits in the corresponding Slot (Slot 0_ q) ON the F-QPCH are set to ON and all subscriber stations MS are set₁-MS₄Must be woken up and monitor Slot 4_ p of the F-PCH/F-CCCH, although the GPM contains only one Slot ready to be sent to the subscriber station MS₃Is disclosedAnd (4) MCP.

Those skilled in the art will recognize that the above-described embodiment uses the first slot of the BPC as a yield (contract) to the existing standard. Thus, in general, this restriction is not necessary and any time slot of the BPC previously agreed upon by the access network and the subscriber station may be used. Thus, according to another embodiment, the constraint that the MPC can only be transmitted in the first time slot of the BPC of the F-PCH/F-CCCH is removed. For reasons of terminology uniformity, the term BPC is replaced by the term Multicast Paging Cycle (MPCY). Those skilled in the art will appreciate that the concepts of BPC and MPCY are consistent. Since it is still desirable that subscriber stations not be woken up to monitor every slot of the F-PCH/F-CCCH, a procedure needs to be established to allow a sector to determine in which slot to send a message to a particular multicast group and to allow subscriber stations belonging to that multicast group to determine which slot to monitor. The process is defined by a mapping function, e.g., a hashing function, accepts input parameters, e.g., the total number of slots in the MPCY, and the GROUP _ ID, and outputs a number that identifies a slot in which a paging message containing the common MCP of subscriber stations belonging to the multicast GROUP identified by the GROUP _ ID is to be transmitted. Alternatively, the mapping may be implemented as a table or any other algorithm that maps GROUP _ IDs to slot numbers. Since the subscriber station is given the GROUP _ ID of each GROUP to which the subscriber station belongs, for example, according to a subscription for a re-GROUP; the subscriber station may use a hash function to determine the F-QPCH time slots to monitor to read the BI indicators. This reduces the false alarm probability, i.e., the probability that the subscriber station is awakened for MCP of the multicast group to which the subscriber station does not belong. Those skilled in the art will appreciate that the hash function is used as an example only and that any other mapping function that allows both the access network and the subscriber station to arrive in the same time slot given the same input parameters is acceptable.

An example of a message flow according to the above-described embodiment is illustrated in fig. 6. At time t₁The sector S receives an identifier GROUP _ IDx from an information source (not shown) to indicate a transmission to the GROUP having the identifier GROUP _ IDxThe multicast paging is to be initiated, the group comprising subscriber stations MS _1 and MS _ 2. As discussed, such information sources may include, for example, a server, another subscriber station, or other sources. The sector S creates a common MCP containing GROUP _ IDx for the subscriber stations MS _1 and MS _2 and enters the GROUP _ IDx and the number of slots of MPCY together into a mapping function. Referring to fig. 7, the hash function returns an indication that MCP for GROUP _ IDx is ready to be sent in Slot 0_ p. At time t2, indicating the beginning of the time Slot (Slot 0_ q) of the F-QPCH corresponding to Slot 0_ p of the F-CCCH, sector S sets the BI bit to ON. The same hash function is used to determine which subscriber station MS _1 and MS _2 monitoring the Slot of the F-QPCH detects that the BI bit in Slot 0_ q is set to ON. The subscriber stations MS _1 and MS _2 are subsequently woken up to be at the time t₃Slot 0_ p is monitored. At time t₃Indicating the start of Slot 0_ p, sector S transmits MCP as part of a paging message, e.g., GPM.

As represented in fig. 5, MS _3 is a member of a multicast GROUP other than the multicast GROUP represented by GROUP _ IDx. Since no request for a multicast page for the multicast group to which MS _3 belongs is received, there is no need to announce in Slot 1_ p of the F-CCCH, while the BI bit in the F-QPCH Slot corresponding to Slot 1_ q of the F-CCCH is set to OFF.

In another embodiment, the subscriber station is notified of a multicast page through a higher protocol layer than the air interface signaling layer. As is well known in the art, layering (layering) is a method of organizing communication protocols with well-defined encapsulated data between otherwise decoupled (de-coupled) processing entities, i.e., layers. The protocol layers are implemented on both the base station 110 and the remote station 116. According to the Open Systems Interconnection (OSI) model, protocol layer L1 provides for the transmission and reception of radio signals between a base station and a remote station, layer L2 provides for the correct transmission and reception of signaling messages, and layer L3 provides for control messaging for the communication system. Layer L3 initiates and terminates signaling messages according to the semantics and timing of the communication protocol between base station 110 and remote station 116. In cdma2000 systems, the air interface signaling layer L1 refers to the physical layer, L2 refers to the Link Access Control (LAC) layer or the medium access control layer (MAC), and L3 refers to the signaling layer. Above the signaling layer are the layers numbered L4-L7 according to the 0SI model and referred to as the transport layer, session layer, presentation layer and application layer.

According to this embodiment, a link layer session is established between an information source and a subscriber station using an existing communication system interface. Such link layer protocols may include, for example, point-to-point protocol (PPP), Serial Line Internet Protocol (SLIP), or other link layer protocols known to those skilled in the art may be used without departing from the scope of the invention. The link layer protocol IS described in documents well known to those skilled in the art, such as the IS-707 standard. The multicast page announce message is then sent over an Internet Protocol (IP) connection of the link layer session.

Fig. 8 illustrates an example of a message flow according to another embodiment. At time t1, sector S receives an indication Page (MS _1) from the information source through the Packet Service Data Node (PSDN) that a multicast Page to be sent to the group including subscriber station MS _1 is to be initiated. The sector S generates a paging record to be sent to the subscriber station MS _1 for requesting a page setting of ppp (dp). Because the requested page is a point-to-point type page, the page record is individual for each member subscriber station. According to IS-707, such a service option IS S033. As discussed above, the service option is included in part of the content of the paging record. Sector S is followed by the generation of an appropriate paging message, e.g. GPM, and waits until time t₂Waiting paging slots are allocated to the subscriber station MS _ 1. At time t₂The paging message is transmitted to MS _1 as part of the GPM (DP: S033). In one embodiment, subscriber station MS _1 acknowledges receipt of MCP at time t 3. As illustrated in fig. 8, in a communication system in accordance with the IS-2000 standard, the response includes a page response message (PRM (S033)) modulated on a reverse channel, e.g., an access channel. At time t₄Sector S sends an announcement indicating which channel is ready for multicast paging. In a communication system according to the IS-2000 standard, such notification IS carried out on an Extended Channel Assignment Message (ECAM)Is transmitted. Thus, an S033 page is established on the channel allocated by ECAM. PPP between the source PDSN and the subscriber station MS _1 at time t when the S033 page is established₅Is established. MS _1 is then notified via PPP about the start of the multicast page. The remaining subscriber stations belonging to the multicast group and interested in the multicast page follow the process described above. (only one additional subscriber station MS _2 is shown for simplicity). According to another embodiment, after receiving an advertisement from a source for a multicast page for a GROUP identified by a GROUP _ ID, a sector transmits a multicast address page record to all subscriber stations in the GROUP to which the multicast page is to be sent to request establishment of a link layer protocol. As discussed above, subscriber stations belonging to the group identified by the GRPUP _ ID need not be assigned the same time slot on the paging channel. Therefore, any of the solutions described above for the correct delivery of multicast addressed pages can be applied.

When a subscriber station belonging to the group responds to the multicast addressed page by sending a PRM, the sector and the subscriber station set a link layer protocol, e.g., S033, as discussed above and inform the subscriber station about the start of the multicast page through the link layer protocol. The link layer protocol paging setup and announcement is then repeated for each remaining subscriber station. Such individual link layer protocol settings are possible because although the access network does not need to know the identity of the individual subscriber station when sending the multicast addressed page, these identities are revealed when receiving a response from the subscriber station.

Response to multicast paging initiation announcement

As discussed above, when a multicast page is initiated, subscriber stations that are members of the multicast group must be notified. When a subscriber station receives an announcement that multicast is being initiated, there are several options for whether and how the subscriber station responds to the announcement.

Alternatively, a subscriber station is not required to respond even though the subscriber station is interested in participating in the multicast communication. This choice may be acceptable, for example, in multicast services, services of general interest and not important for delivering which service to each subscriber station, such as stock market information updates, video streaming, and other information of a similar nature.

Alternatively, if a subscriber station is interested in participating in the multicast communication, the subscriber station is always required to respond. The response includes: for example, a message is sent to the access network on the reverse channel. An example of such a message in a communication system in accordance with the IS-2000 standard IS a page response message transmitted on a reverse access channel (R-ACH), a reverse enhanced access channel (R-EACH), and a reverse common control channel (R-CCCH). Such a response must contain information for the next action to be taken by the access network. Depending on the design characteristics of the communication system, such information may indicate whether the subscriber station is interested in joining the multicast; whether the subscriber station is not interested in joining the multicast; whether the subscriber station is interested but cannot join because it does not support the required configuration, e.g., data rate.

The access network waits for a response from the member subscriber stations before channel assignment. This selection is required for services that require the access network to know whether each subscriber station is participating. In addition, the response allows the access network to decide whether to allocate a shared channel or a dedicated channel for the multicast content. This response prevents the access network from allocating dedicated traffic channels to the participating subscriber stations when a decision is made to allocate a dedicated channel to each subscriber station.

As explained above, in one embodiment, each subscriber station that is a member of a multicast group is notified of the start of a multicast page to be sent to the group by a common message addressed to the member subscriber stations. When a subscriber station that is not a member of the group identified in the common message receives an announcement, the subscriber station may ignore the announcement and not respond. However, if ad hoc multicast group information is supported, all subscriber stations receiving the announcement are required to respond. The term ad hoc multicast group is used herein to denote a multicast group that is not subscribed to, but is created upon initiation of a multicast page. Regardless of whether ad hoc multicast group information is supported, the requirement for a response to the common message announcement elicits a response from the subscriber station receiving the announcement. Since many subscriber stations will respond, a method of staggering these response messages, e.g., page response messages from subscriber stations in the group, may be implemented to avoid collisions from response bursts.

According to another option, a subscriber station is always required to respond even if the subscriber station is not interested in joining the multicast service. This option is required for services that require the access network to know with certainty whether each subscriber station is participating. Unlike previous options, this option allows the access network to positively distinguish between subscriber stations that do not respond because they are not interested in the multicast page and subscriber stations that do not respond because they fail to receive an advertisement. Thus, the access network may take appropriate action, such as repeating the advertisement. Other considerations described with respect to the previous selection are applicable.

Those skilled in the art will appreciate that the foregoing options are for different purposes of illustration only. The communication system may use any suitable choice for a multicast page. For example, when a multicast page origination for which delivery to each subscriber station is not important, no response from the member subscriber stations may be required. A response may be required when the same member subscriber station needs to participate in a subsequent multicast page. An indication of whether and what responses are required to access the network may be indicated to the subscriber station, for example, by signaling contained in the announcement message. However, any other form of response indication is envisioned.

Channel allocation for multicast paging initiation

As mentioned above, communication system 100 provides content to member subscriber stations over forward link channel 114. Thus, the forward link channel, whether shared between member subscriber stations or established individually between each member subscriber station and the base station, must be assigned by an entity of communication system 100 before multicast services can be initiated.

As discussed above, there are multiple methods of advertising, multiple methods of responding, and multiple methods of channel allocation. Thus, many possible combinations of advertisements, responses and channel assignments are as described in the following embodiments:

as discussed, in one embodiment, the member subscriber stations are notified about the multicast page by a common overhead message or a common paging message. Since the multicast service announcement is broadcast to multiple subscriber stations in a common message rather than to individual subscriber stations, the entity generating the common message need not know the identity of the individual member subscriber stations of the multicast group.

If the member subscriber station does not require a response, multicast service traffic channels, such as channel identification (Walsh code in a communication system according to the IS-2000 standard), data rate, and other assignment information, may be included as part of the notification, as IS well known to those skilled in the art. Thus, in the case of advertising via a common overhead message, the channel allocation information may be part of the overhead message; the channel allocation information may be part of the MCP in case of being advertised by a common paging message. Since the channel allocation information is multicast and does not require a response, the type of channel allocation must be a shared channel. Alternatively, the channel allocation information may be communicated to the subscriber station separately from the announcement.

Upon processing of the message by the subscriber station, the subscriber station of interest begins monitoring the assigned channel to receive multicast service traffic.

An example of a message flow according to the above-described embodiment is illustrated in fig. 9. At time t₁The sector S receives an indication GROUP _ IDx to indicate that a multicast page sent to the GROUP with the identifier GROUP _ IDx is to be initiated. The indication may be provided by other entities of the communication system, e.g. a base station controller, a PSTN, an information source (not shown), other entities. Alternatively, the sector S receives the subscriber stations MS _1 and MS _2And (5) identifying. The sector S then determines the identifier of the multicast GROUP _ IDx comprising the subscriber stations MS _1 and MS _2, e.g. by querying a database. As discussed, the information source may include, for example, a server, other subscriber stations, or any other source known to those skilled in the art.

The sector S includes the identifier and channel assignment information in the overhead message, which in one embodiment includes a broadcast system parameters message BSPM. Sector S at time t_2oThe BSPM (GROUP _ IDx, channel assignment Information) is broadcast. Subscriber stations MS _1 and MS _2, which are members of the GROUP having the identifier, receive BSPM (GROUP _ IDx), process BSPM and will be at time t₃Appropriate action is taken, for example, tuning to and starting monitoring the physical channel on which the identified multicast page is to be transmitted. At time t₄The content of the multicast service starts to be transmitted on the Traffic channel (Traffic for group _ IDx). As discussed, the overhead message BSPM repeats itself periodically, so if an identifier and channel allocation information are included in each message, the identifier and the channel allocation information will be transmitted in the next instances of the overhead message BSPM, similarly. Only at time t_2oAn example of (2).

Alternatively, sector S includes the identifier and channel assignment information in a paging message, such as a General Paging Message (GPM). The sector S determines the time slot to monitor on the paging channel by using the member subscriber stations of any of the above embodiments. The sector then at time t_2pGPM (MCP: GROUP _ IDx, Channel Assignment Information) is transmitted in this slot. Subscriber stations MS _1 and MS _2 are members of the GROUP having the identifier and receive GPM (MCP: GROUP _ IDx, Channel Assignment Information) at time t₃The GPM is processed and appropriate action is taken, e.g., tuning to and starting monitoring the physical channel on which the identified multicast page is ready to be transmitted. At time t₄The content of the multicast service starts to be transmitted on the Traffic channel (Traffic for Group _ IDx).

If a member subscriber station is required to respond prior to channel assignment, the interested subscriber station sends a response upon receiving the multicast service announcement in the common message. Such a response includes, for example, a signaling message (a new type of message, e.g., a multicast service join message as a response to the common overhead message or a page response message as a response to the common page message) to indicate that the interested subscriber station wishes to join the multicast service.

Upon receiving the responses, the entity of the access network for channel allocation considers the number of responses to determine the type of channel to be allocated. In one embodiment, the access network compares the number of responses to a threshold and assigns a channel type according to the result of the comparison. If the entity decides to allocate a shared channel, the access network sends a shared message channel allocation message, such as a Multicast Channel Allocation Message (MCAM), which contains information for the shared multicast service traffic channel. Thus, the MCAM uses the multicast address to assign the shared channel to the subscriber station of interest.

As explained above, subscriber stations belonging to the GROUP identified by GROUP _ IDx need not be assigned the same time slot on the paging channel. Therefore, a method capable of efficiently delivering multicast paging initiation information is required.

In one embodiment, upon receiving the notification, the subscriber station is required to monitor the paging channel in an unslotted mode; thus, the MCAM may be transmitted using any paging channel slot.

In another embodiment, the MCAM is transmitted over a slot using the same method as used to determine the slot to transmit the multicast address advertisement.

In another embodiment, the common overhead message or the common paging message indicates a paging channel slot number, which is a slot in which the subscriber station is required to monitor the MCAM.

In another embodiment, the MACM is transmitted on every time slot monitored by the subscriber station.

Those skilled in the art will appreciate that the embodiments described herein are treated separately for illustration only. The communication system will use the appropriate embodiments for multicast paging services. The selection of an embodiment may, for example, be specified in the advertisement.

An example of a message flow according to the above-described embodiment is illustrated in fig. 10. At time t₁The sector S receives an indication GROUP _ IDx to indicate that a multicast page sent to the GROUP with the identifier GROUP _ IDx is to be initiated. The indication may be provided by other entities of the communication system, e.g. a base station controller, a PSTN, an information source (not shown), other entities. Alternatively, the sector S receives the identities of the subscriber stations MS _1 and MS _ 2. The sector S then does include the identifier of the multicast GROUP IDx determined by the subscriber stations MS _1 and MS _2, e.g., by querying a database. As discussed, the information source may include, for example, a server, other subscriber stations, or any other source known to those skilled in the art.

The sector S includes an identifier in the overhead message, which in one embodiment includes a broadcast system parameters message BSPM. Sector S at time t_2oThe BSPM (GROUP _ IDx) is broadcast. Subscriber stations MS _1 and MS _2 are members of the GROUP having this identifier, receive the BSPM (GROUP _ IDx), process the BSPM and take appropriate action, e.g., send a response message. As discussed, the overhead message BSPM repeats itself periodically, so if an identifier is included in each message, it will be transmitted in the next instance(s) of the overhead message BSPM. Only at time t_2oAn example of (2).

Alternatively, sector S includes the identifier in a paging message, such as a General Paging Message (GPM). Sector S then determines the time slot on the paging channel monitored by the member subscriber station and at time t_2pGPM (MCP: GROUP _ IDx) is transmitted in this slot. The subscriber stations MS _1 and MS _2 are provided withThe members of the GROUP of identifiers, receiving the GPM (MCP: GROUP _ IDx), process the GPM and take appropriate action, e.g., send a response message.

Whatever common message is used for notification, the subscriber stations MS _1 and MS _2 are at time t, respectively₃And t₄And sending a response. When a response is received, the entity of the access network responsible for channel allocation determines to allocate a shared channel. The sector S determines the method of sending the common channel assignment message, e.g. MCAM, and at time t₅Transmitting the MCAM including information for sharing a multicast service traffic channel MCAM (channel Assignment information). The subscriber stations MS _1 and MS _2 process the MCAM and take appropriate action, e.g. at time t₆Tune to and begin monitoring the physical channel on which the identified multicast page is ready to be transmitted. At time t₇The content of the multicast service starts to be transmitted on the Traffic channel (Traffic for Group _ IDx).

In another embodiment, if the entity decides to allocate a shared channel, the access network sends an Individual Channel Assignment Message (ICAM) containing the shared multicast service traffic channel for each responding member subscriber station. In the context of a communication system in accordance with the IS-2000 standard, the ICAM may include, for example, an extended channel assignment message.

Such individual assignment is possible because although the access network does not need to know the identity of the individual subscriber station when the advertisement is sent, these identities are revealed upon receiving a response from the subscriber station.

It is noted that since the shared multicast service traffic channel is individually allocated as in point-to-point paging, any known method for point-to-point traffic channel allocation may be used. Thus, the problem of when to send the ICAM for each subscriber station does not arise because the access network knows when each interested subscriber station is going to monitor the paging channel.

An example of a message flow according to the above-described embodiment is illustrated in fig. 11. At time t₁The sector S receives an indication GROUP _ IDx to indicate that the multicast page sent to the GROUP with identifier GROUP _ IDx is to be initiated. The indication may be provided by other entities of the communication system, e.g. a base station controller, a PSTN, an information source (not shown), other entities. Alternatively, the sector S receives the identities of the subscriber stations MS _1 and MS _ 2. The sector S then determines the identifier of the multicast GROUP _ IDx comprising the subscriber stations MS _ I and MS _2, e.g. by querying a database. As discussed, the information source may include, for example, a server, other subscriber stations, or any other source known to those skilled in the art.

The sector S includes an identifier in the overhead message, which in one embodiment includes a broadcast system parameters message BSPM. Sector S at time t_2oThe BSPM (GROUP _ IDx) is broadcast. Subscriber stations MS _1 and MS _2 are members of the GROUP having the identifier and receive the BSPM (GROUP _ IDx) to process the BSPM and take appropriate action, e.g., send a response message. As discussed, the overhead message BSPM repeats itself periodically, so if an identifier is included in each message, the identifier will be transmitted at the next instance of the overhead message BSPM. Only at time t_2oAn example of (2).

Alternatively, sector S includes the identifier in a paging message, such as a General Paging Message (GPM). Sector S then determines the time slot on the paging channel monitored by the member subscriber station and at time t_2pGPM (MCP: GROUP _ IDx) is transmitted in this slot. Subscriber stations MS _1 and MS _2 are members of the GROUP with the identifier, receive a GPM (MCP: GROUP _ IDx) process the GPM and take appropriate action, e.g., send a response message.

Whatever common message is used for notification, the subscriber stations MS _1 and MS _2 are at time t, respectively₃And t₄And sending a response. Upon receiving the response, the entity of the access network responsible for channel assignment determines to assign a dedicated channel. Since the sector S knows the identities of the subscriber stations MS _1 and MS _2 from the received response, the sector S determines in which time slot the subscriber stations MS _1 and MS _2 are to monitor the paging channel according to the response. Sector S waits until time t₅Waiting for a paging slot monitored by the subscriber station MS _1 and delivering a respective icam (channel Assignment information) to the subscriber station MS _ 1; similarly, sector S waits until time t₆Waits for a paging slot monitored by the subscriber station MS _2 and delivers a respective icam (channelsignation information) to the subscriber station MS _ 2. Subscriber stations MS _1 and MS _2 process the ICAM and take appropriate action, e.g., at time t, respectively₅And t₆Tune to and begin monitoring the physical channel on which the identified multicast page is ready to be transmitted. At time t₇The content of the multicast service starts to be transmitted on the traffic channel (Trafficfor Group IDx).

In another embodiment, if the entity decides to assign a dedicated channel to each responding member subscriber station, the access network sends an individual channel assignment message containing information for the dedicated multicast service traffic channel to each responding member subscriber station.

Such individual assignment is possible because although the access network does not need to know the identity of the individual subscriber station when sending the announcement, these identities are revealed upon receiving a response from the subscriber station.

Since the multicast service traffic channels are individually allocated as in point-to-point paging, any known allocation for point-to-point traffic channels may be used. In particular, the access network knows when each interested subscriber station is to monitor the paging channel.

An example of a message flow according to the above-described embodiment is illustrated in fig. 12. At time t₁The sector S receives an indication GROUP _ IDx to indicate that a multicast page sent to the GROUP with the identifier GROUP _ IDx is to be initiated. The indication may be provided by other entities of the communication system, e.g. a base station controller, a PSTN, an information source (not shown), other entities. Alternatively, the sector S receives the identities of the subscriber stations MS _1 and MS _ 2. The sector S then determines the identifier of the multicast GROUP _ IDx comprising the subscriber stations MS _1 and MS _2, e.g. by querying a database. As discussed, information sources may include, for example, servers, othersA subscriber station, or any other source known to those skilled in the art.

The sector S includes the identifier in an overhead message, which in one embodiment includes a broadcast system parameters message BSPM. Sector S at time t_2oThe BSPM (GROUP _ IDx) is broadcast. Subscriber stations MS _1 and MS _2 are members of the GROUP having the identifier and receive the BSPM (GROUP _ IDx) to process the BSPM and take appropriate action, e.g., send a response message. As discussed, the overhead message BSPM repeats itself periodically, so that if the identifier is included in each message, it will be transmitted in the next instance(s) of the overhead message BSPM. Only at time t_2oAn example of (2).

Whatever common message is used for notification, the subscriber stations MS _1 and MS _2 are at time t, respectively₃And t₄And sending a response. Upon receiving the response, the entity of the access network responsible for channel assignment determines to assign dedicated channels. Since the sector S knows the identity of the subscriber stations MS _1 and MS _2 from the received response, the sector S determines in which time slot the subscriber stations MS _1 and MS _2 are to monitor the paging channel according to the response.

Sector S waits until time t₅Waiting for the paging slot monitored by the subscriber station MS _1 and then delivering a respective icam (channel Assignment information) to the subscriber station MS _ 1. The subscriber station MS _1 processes the ICAM and takes the appropriate action, e.g., at time t₅Tune to and begin monitoring the physical channel on which the identified multicast page is ready to be transmitted.

LikeSector S waits until time t₇Waits for a paging slot monitored by the subscriber station MS _2 and then delivers a separate icam (channel Assignment information) to the subscriber station MS _ 2. The subscriber station MS _2 processes the ICAM and takes the appropriate action, e.g., at time t₆Tune to and begin monitoring the physical channel on which the identified multicast page is ready to be transmitted.

At time t₇The content of the multicast service starts to be transmitted on a dedicated Traffic channel (Traffic for Group _ IDx).

In another embodiment, if the entity decides to assign a dedicated channel to each responding member subscriber station, the access network sends a common channel assignment message, a Multicast Channel Assignment Message (MCAM), which contains information for each individual multicast service traffic channel. Thus, one MCAM uses the multicast address to assign one dedicated multicast service traffic channel to each subscriber station of interest.

As explained, the subscriber stations belonging to the GROUP identified by GROUP _ ID do not have to be allocated the same time slot on the paging channel. Therefore, a method for efficiently delivering multicast paging initiation information is needed.

In another embodiment, the MCAM is transmitted over a slot using the same method as used to determine the slot in which to transmit the multicast address advertisement.

In another embodiment, the common overhead message or the common paging message indicates a paging channel slot number, which is the slot number required by the subscriber station to be required to monitor the MCAM.

Those skilled in the art will appreciate that the embodiments described herein are treated separately for illustration only. The communication system may use suitable embodiments for multicast paging services. The selection of an embodiment may, for example, be specified in the advertisement.

Once the subscriber station processes the message, the interested subscriber station begins monitoring the assigned channel to receive multicast service traffic.

An example of a message flow according to the above-described embodiment is illustrated in fig. 11. At time t₁The sector S receives an indication GROUP _ IDx to indicate that a multicast page sent to the GROUP with the identifier GROUP _ IDx is to be initiated. The indication may be provided by other entities of the communication system, e.g. a base station controller, a PSTN, an information source (not shown), other entities. Alternatively, the sector S receives the identities of the subscriber stations MS _1 and MS _ 2. The sector S then determines the multicast GROUP _ IDx comprising the subscriber stations MS _1 and MS _2, e.g. by querying a database. As discussed, the information source may include, for example, a server, other subscriber stations, or any other source known to those skilled in the art.

The sector S includes the identifier in the overhead message, which in one embodiment comprises a broadcast system parameters message BSPM. Sector S at time t_2oThe BSPM (GROUP _ IDx) is broadcast. Subscriber stations MS _1 and MS _2 are members of the GROUP having the identifier and receive the BSPM (GROUP _ IDx) to process the BSPM and take appropriate action, e.g., send a response message. As discussed, the overhead message BSPM repeats itself periodically, so if an identifier is included in each message, that identifier will be transmitted at the next instance(s) of the overhead message BSPM. Only at time t_2oAn example of (2).

Alternatively, sector S includes the identifier in a paging message, such as a General Paging Message (GPM). Sector S then determines the time slot on the paging channel monitored by the member subscriber station and at time t_2pGPM (MCP: GROUP _ IDx) is transmitted in this slot. Subscriber stations MS _1 and MS _2 are members of a GROUP having the identifier, receive a GPM (MCP: GROUP _ IDx), process the GPM, and adoptTake an appropriate action, e.g., send a response message.

Whatever common message is used for notification, the subscriber stations MS _1 and MS _2 are at time t, respectively₃And t₄And sending a response. When a response is received, the entity of the access network responsible for channel assignment determines to assign a dedicated channel. The sector S determines a method of transmitting the common channel Assignment message, e.g., MCAM, and transmits MCAM including information for the dedicated multicast service traffic channel MCAM (channel Assignment information) at time t 5.

The subscriber station MS _1 processes the MCAM and takes the appropriate action, for example at the time t₆Tune to and begin monitoring the physical channel on which the identified multicast page is ready to be transmitted.

Similarly, subscriber station MS _2 processes MCAM and takes appropriate action, e.g. at time t₆Tune to and begin monitoring the physical channel on which the identified multicast page is ready to be transmitted.

At time t₇The content of the multicast service starts to be transmitted on the Traffic channel (Traffic for Group _ IDx).

In one embodiment, each member subscriber station is notified about the multicast service through an individual paging message. Since the multicast service is transmitted to multiple subscriber stations through multiple individual paging messages, the entity generating the individual paging message does not need to know the identity of the individual member subscriber stations.

If the member subscriber station does not require a response, a multicast service traffic channel, such as a channel identifier (Walsh code in a communication system according to the IS-2000 standard), channel assignment information for the data rate, and other assignment information known to those skilled in the art, can be included as part of the advertisement. Thus, in the case of advertising via a common overhead message, the channel allocation information may be part of the overhead message; in the case of announcement through an individual paging message, the channel allocation information may be part of the individual paging message. Since the channel allocation information is provided in an individual paging message, the types of the allocated channels may be a shared channel as well as a dedicated channel.

Since the member subscriber stations do not require a response to the multicast service announcement, in the case where the entity generating the individual paging message decides to allocate a dedicated channel to each member subscriber station, the entity may allocate dedicated resources for member subscriber stations not interested in participating in the multicast service. It is therefore desirable to be able to determine whether member subscriber stations assigned a dedicated channel are interested in participating in the multicast service, so that the dedicated channel for the group of non-participating members can be reclaimed (replayed) and reused for other services, such as conventional point-to-point paging. In one embodiment, the access network determines whether the member subscriber stations are active on the assigned reverse link channel after the dedicated channel is assigned and the multicast service has been initiated.

An example of a message flow according to the above embodiment is illustrated in fig. 14, where a shared channel is allocated. At time t₁The sector S receives the identities of the subscriber stations MS _1 and MS _2GROUP _ IDx, which comprise a GROUP with an identifier GROUP _ IDx for which a multicast call is to be initiated. Alternatively, the sector S receives the GROUP identifier GROUP _ IDx. This information may be provided by other entities of the communication system, e.g., a base station controller, PSTN, information source (not shown), other entities. The sector S then determines the identity of the subscriber stations MS _1 and MS _2, e.g. by querying a database. The sector S then creates an individual MCP containing the identifier GROUP IDx and channel allocation information for each subscriber station MS _1 and MS _2 and includes this MCP in a paging message, e.g., a General Paging Message (GPM).

The sector S then determines the time slots on the paging channels by the member subscriber stations MS _1 and MS _ 2. At time t₂Sector S transmits GPM (MCP: GROUP _ IDx, Channel Assignment) on a time slot monitored by member subscriber station MS _1Info). Subscriber station MS _1 receives the GPM (MCP: GROUP _ IDx, channel assignment Info), processes the GPM and takes appropriate action, e.g., tunes to and starts monitoring the physical channel on which the identified multicast page is to be transmitted.

At time t₂Sector S transmits GPM (MCP: GROUP _ IDx, Channel Assignment Info) on the time slot monitored by member subscriber station MS _ 2. Subscriber station MS _2 receives the GPM (MCP: GROUP _ IDx, Channel Assignment Info), processes the GPM and takes appropriate action, e.g., tunes to and starts monitoring the physical Channel on which the identified multicast page is to be transmitted.

At time t₄The content of the multicast service starts to be transmitted on a shared Traffic channel (Traffic for Group _ IDx).

An example of a message flow according to the above embodiment is illustrated in fig. 15, where a dedicated channel is allocated. At time t₁The sector S receives the identities of the subscriber stations MS _1 and MS _2GROUP _ IDx, which comprise a GROUP with an identifier GROUP _ IDx for which a multicast page is to be initiated. Alternatively, the sector S receives a set of identifiers GROUP _ IDx. This information may be provided by other entities of the communication system, e.g., a base station controller, PSTN, information source (not shown), other entities. The sector S then determines the identity of the subscriber stations MS _1 and MS _2, e.g. by querying a database. The sector S then creates an individual MCP containing the identifier GROUP IDx and channel allocation information for each subscriber station MS _1 and MS _2 and includes this MCP in a paging message, e.g., a General Paging Message (GPM).

The sector S then determines the time slots on the paging channel monitored by the member subscriber stations MS _1 and MS _ 2. At time t₂Sector S transmits GPM (MCP: GROUP _ IDx, Channel Assignment Info for MS _1) on a time slot monitored by member subscriber station MS _ 1. Subscriber station MS _1 receives the GPM (MCP: GROUP _ IDx, Channel Assignment Info for MS _1), processes the GPM and takes appropriate action, e.g., at time t₃Tuning to and starting to monitor for ready to transmit (Traffic for MS _1) for a subscriber stationPhysical channel for multicast paging of MS _ 1.

At time t₄Sector S transmits GPM (MCP: GROUP _ IDx, Channel Assignment Info for MS _2) on a time slot monitored by member subscriber station MS _ 2. Subscriber station MS _2 receives the GPM (MCP: GROUP _ IDx, channel Assignment Info for MS _2), processes the GPM and takes appropriate action, e.g., at time t₃Tune to and begin monitoring physical channels ready to transmit (Traffic for MS _2) multicast paging for MS _2

If a member subscriber station is required to respond prior to channel assignment, when a multicast service announcement is received in an individual paging message, the interested subscriber station sends a response, e.g., a signaling message similar to the paging response message, to indicate the interested subscriber station's desire to participate in the multicast service

When receiving the response, the entity of the access network responsible for channel allocation may consider the number of responses to determine the type of channel allocated. In one embodiment, the access network compares the number of responses to a threshold for corruption and assigns a type of channel according to the result of the comparison. If the entity decides to allocate a shared channel, the access network sends a common channel allocation message, e.g., a Multicast Channel Allocation Message (MCAM), which contains information for the shared multicast service traffic channel. Thus, MCAM uses a multicast address to assign a shared channel to subscriber stations of interest

As explained above, subscriber stations belonging to the GROUP IDx identified by GROUP _ IDx do not have to be allocated the same time slot on the paging channel. Therefore, a method for efficiently delivering multicast paging initiation information is needed.

In another embodiment, the MCAM is transmitted over a slot using the same method as used to determine the slot to transmit the multicast address advertisement. In addition to

In one embodiment, the common overhead message or the common paging message indicates a paging channel slot number, which is a slot in which the subscriber station is required to monitor for MCAM

Those skilled in the art will appreciate that the embodiments described herein are treated separately for illustration only. The communication system may use suitable embodiments for multicast paging services. The choice of embodiment may be, for example, specified in the announcement.

When a subscriber station processes a message, the interested subscriber station begins monitoring the assigned channel to receive multicast service traffic

An example of a message flow according to the above-described embodiment is illustrated in fig. 16. At time t₁The sector S receives the identities of the subscriber stations MS _1 and MS _2GROUP _ IDx, which comprise a GROUP with an identifier GROUP _ IDx for which a multicast page is to be initiated. Alternatively, the sector S receives the GROUP identifier GROUP _ IDX, which information may be provided by other entities of the communication system, e.g. a base station controller, PSTN, an information source (not shown), other entities. The sector S then determines the identity of the subscriber stations MS _1 and MS _2, e.g. by querying a database. The sector S then creates an individual MCP containing the identifier GROUP IDx and channel allocation information for each subscriber station MS _1 and MS _2 and includes this MCP in a paging message, e.g., a General Paging Message (GPM).

The sector S then determines the time slots on the paging channel monitored by the member subscriber stations MS _1 and MS _ 2. At time t₂The sector S transmits a GPM (MCP: GROUP _ IDx) on a time slot monitored by the member subscriber station MS _ 1. Subscriber station MS _1 receives GPM (MCP: GROUP _ IDx) and at time t₃A response is sent.

At time t₄On the time slot monitored by the member subscriber station MS _2, the sector S sendsAnd GPM (MCP: GROUP _ IDx). Subscriber station MS _2 receives GPM (MCP: GROUP _ IDx) and at time t₅A response is sent.

When a response is received, the entity of the access network responsible for channel allocation determines to allocate the shared channel. Sector S waits until time t₆Waits for a paging slot monitored by the subscriber station MS _1 and then delivers a separate icam (channel Assignment information) to the subscriber station MS _ 1. The subscriber station MS _1 processes the ICAM and takes appropriate action, e.g., tunes to and starts monitoring the physical channel on which the identified multicast page is ready to be transmitted.

Similarly, sector S waits until time t₇Waits for a paging slot monitored by the subscriber station MS _2 and then delivers a separate icam (channel Assignment information) to the subscriber station MS _ 2. The subscriber station MS _2 processes the ICAM and takes appropriate action, e.g., tunes to and starts monitoring the physical channel on which the identified multicast page is ready to be transmitted.

At time t₈The multicast service starts to be transmitted on the Traffic channel (Traffic for Group _ IDx).

Such individual assignment is possible because although the access network does not need to know the identity of the individual subscriber station when the advertisement is sent, these identities are revealed when a response is received from the subscriber station.

It is noted that since the shared multicast service traffic channel is individually assigned in point-to-point paging, any known method for point-to-point traffic channel assignment may be used. Thus, the problem of when to send the ICAM for each subscriber station is not present because the access network knows when each interested subscriber station is going to monitor the paging channel.

An example of a message flow according to the above-described embodiment is illustrated in fig. 17. At time t₁The sector S receives the identities of the subscriber stations MS _1 and MS _2GROUP _ IDx, which comprise a GROUP with an identifier GROUP _ IDx for which a multicast page is to be initiated. Alternatively, the sector S receives the GROUP identifier GROUP _ IDx. This information may be provided by other entities of the communication system, e.g., a base station controller, PSTN, information source (not shown), other entities. The sector S then determines the identity of the subscriber stations MS _1 and MS _2, e.g. by querying a database. The sector S then creates an individual MCP containing the identifier GROUP IDx and channel allocation information for each subscriber station MS _1 and MS _2 and includes this MCP in a paging message, e.g., a General Paging Message (GPM).

The sector S then determines the time slots on the paging channel monitored by the member subscriber stations MS _1 and MS _ 2. At time t₂In the time slot monitored by the member subscriber station MS _1, the sector S transmits GPM (MCP: GROUP _ IDx). Subscriber station MS _1 receives GPM (MCP: GROUP _ IDx) and at time t₃A response is sent.

At time t₄The sector S transmits a GPM (MCP: GROUP _ IDx) on a time slot monitored by the member subscriber station MS _ 2. Subscriber station MS _2 receives GPM (MCP: GROUP _ IDx) and at time t₅A response is sent.

When a response is received, the entity of the access network responsible for channel allocation determines to allocate some shared channels. The sector S determines the method of sending an individual channel assignment message, e.g. ICAM, to each subscriber station MS _1 and MS _2 and respectively at time t₆And t₇Transmitting an ICAM including information for a shared multicast service channel (ICAM). The subscriber stations MS _1 and MS _2 process the ICAM and take appropriate action, e.g., at time t₇Tune to and begin monitoring the physical channel on which the identified multicast page is ready to be transmitted. At time t₇The multicast service content starts to be transmitted on the Traffic channel (Traffic for Group _ IDx).

In another embodiment, if the entity decides to allocate a dedicated channel, the access network sends a common channel assignment message, a Multicast Channel Assignment Message (MCAM), which contains information for the dedicated multicast service traffic channel. Thus, the MCAM uses the use of multicast addresses to assign shared channels to interested subscriber stations.

As explained above, the subscriber stations belonging to the GROUP identified by GROUP _ IDx do not have to be allocated the same time slot on the paging channel. Therefore, a method for efficiently delivering multicast paging initiation information is needed.

In one embodiment, upon receiving the notification, the subscriber station is required to monitor the paging channel in an unslotted mode; thus, the MCAM may be transmitted in any paging channel slot.

When a subscriber station processes a message, the interested subscriber station begins monitoring the assigned channel to receive multicast service traffic.

An example of a message flow according to the above-described embodiment is illustrated in fig. 18. At time t₁The sector S receives the identities of the subscriber stations MS _1 and MS _2GROUP _ IDx, which comprise a GROUP with an identifier GROUP _ IDx,a multicast page is to be initiated for the group. Alternatively, the sector S receives a set of identifiers GROUP _ IDx. This information may be provided by other entities of the communication system, e.g., a base station controller, PSTN, information source (not shown), other entities. The sector S then determines the identity of the subscriber stations MS _1 and MS _2, e.g. by querying a database. The sector S then creates an individual MCP containing the identifier GROUP IDx and channel allocation information for each subscriber station MS _1 and MS _2 and includes the MCP in a paging message, such as a General Paging Message (GPM).

Upon receiving the response, the entity of the access network responsible for channel allocation determines to allocate a dedicated channel. Sector S determines the method of transmitting a common channel assignment message, e.g. MCAM, and at time t₆Transmitting an MCAM containing traffic channels for a dedicated multicast service MCAM (Channel Assignment Information for MS _1, Channel Assignment Information for MS _ 2). The subscriber stations MS _1 and MS _2 process the ICAM and take appropriate action, e.g., at time t₇And t₈Tune to and begin monitoring physical channels Traffic for MS _1 and Traffic for MS _2, respectively, on which to prepare the physical channel on which the identified multicast page is to be transmitted, respectively.

In another embodiment, if the entity decides to allocate a dedicated Channel, the access network sends Individual Channel Assignment messages (independent Channel Assignment Message-ICAM) that contain information for the shared multicast service traffic Channel to each responding member subscriber station. In the context of a communication system in accordance with the IS-2000 standard, the ICAM may include, for example, the use of an extended channel assignment message.

It is noted that since the shared multicast service traffic channel is individually allocated as in point-to-point paging, any known method for point-to-point traffic channel allocation may be used. Thus, the problem of when to send the ICAM for each subscriber station is not present because the access network knows when each interested subscriber station is going to monitor the paging channel.

An example of a message flow according to the above-described embodiment is illustrated in fig. 19. At time t₁The sector S receives the identities of the subscriber stations MS _1 and MS _2GROUP _ IDx, which comprise a GROUP with an identifier GROUP _ IDx for which a multicast page is to be initiated. Alternatively, the sector S receives a set of identifiers GROUP _ IDx. This information may be provided by other entities of the communication system, e.g., a base station controller, PSTN, information source (not shown), other entities. The sector S then determines the identity of the subscriber stations MS _1 and MS _2, e.g. by querying a database. The sector S then creates an individual MCP containing the identifier GROUP IDx and channel allocation information for each subscriber station MS _1 and MS _2 and includes this MCP in a paging message, e.g., a General Paging Message (GPM).

At time t₄In the time slot monitored by the member subscriber station MS _2, the sector S transmits GPM (MCP: GROUP _ IDx). Subscriber station MS _2 receives GPM (MCP: GROUP _ IDx) and at time t₅A response is sent.

Upon receiving the response, the entity of the access network responsible for channel allocation determines to allocate a dedicated channel. Sector S waits until time t₆Waiting for seeking monitored by subscriber station MS _1Call slot and then deliver individual ICAM (Channel Assignment Information for MS _1) to subscriber station MS _ 1. The subscriber station MS _1 processes the ICAM and takes the appropriate action, e.g., at time t₇Tunes to and starts monitoring a physical channel ready to transmit (Traffic for MS _1) for a multicast page for subscriber station MS _ 1.

Similarly, sector S waits until time t₈And waits for a paging slot monitored by the subscriber station MS _2 and then delivers a separate ICAM (Channel Assignment Information for MS _2) to the subscriber station MS _ 2. The subscriber station MS _2 processes the ICAM and takes the appropriate action, e.g., at time t₉Tunes to and starts monitoring a physical channel that is ready to transmit a multicast page for (Traffic for MS _2) subscriber station MS _ 2.

Those skilled in the art will appreciate that the foregoing embodiments have been presented separately for purposes of illustration only. A communication system may use any embodiment suitable for multicast services. For example, different embodiments may be used for each sector for multicast services to be delivered to a multicast group whose members are within the coverage area of different sectors. Thus, one sector can use multicast advertisements, request responses, and allocate dedicated channels. Another sector may use individual advertisements, request responses, and allocate shared channels. Another sector may use multicast announcement, request a response and assign a shared channel to some subscriber stations and a dedicated channel to the remaining subscriber stations.

Those skilled in the art will appreciate that although the flow diagrams are shown in a serial order for ease of understanding, certain steps may be implemented 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, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

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 illustrative 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, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.

The implementation or execution of the various illustrative logical blocks, modules, and algorithm steps described in connection with the embodiments described herein may be implemented or performed with: a general purpose processor, 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, discrete hardware components, or any combination designed to perform the functions described herein. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any 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. The ASIC may reside in a user terminal. 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 the disclosure of this patent document may contain material that 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 patent file or records, but otherwise reserves all copyright rights whatsoever.

Claims

1. A method for multicast service advertisement in a communication system, comprising:

including an indicator into a first time slot on a first channel; and

if the multicast group service announcement is indicated by the indicator, the multicast service announcement is included in a message communicated in a second time slot on the second channel, the second time slot corresponding to the first time slot.

2. The method of claim 1, wherein including an indicator into the first time slot comprises:

determining a broadcast paging cycle; and

determining the first time slot according to the multicast paging cycle and a multicast group identifier.

3. The method of claim 2, wherein determining the first time slot according to the multicast paging cycle and a multicast group identifier comprises:

inputting the multicast paging cycle and the multicast group identifier into a hash function; and

the first time slot is set to the output value of the hash function.

4. The method of claim 1, wherein the step of including the multicast service announcement into a message communicated in a second slot on a second channel comprises:

the multicast service announcement is included in a message communicated in a second slot on a second channel, the second slot being offset from the first slot by a predetermined interval.

5. The method of claim 4, wherein the second time slot is offset from the first time slot by 100 milliseconds.

6. A method for multicast service notification for a subscriber station in a communication system, comprising:

decoding an indicator from a first slot on a first channel; and

decoding the multicast service announcement in a second slot on the second channel if the multicast service announcement is indicated by the indicator, the second slot corresponding to the first slot.

7. The method of claim 6, wherein decoding an indicator from a first slot on a first channel comprises:

determining a broadcast paging cycle; and

determining a first slot according to the multicast paging cycle and a multicast group identifier.

8. The method of claim 7, wherein determining the first time slot according to the multicast paging cycle and a multicast group identifier comprises:

the first time slot is set to the output value of the hash function.

9. The method of claim 6, wherein the second time slot is offset from the first time slot by a predetermined interval.

10. The method of claim 9, wherein the second time slot being offset from the first time slot by a predetermined interval comprises:

the second time slot is offset from the first time slot by 100 milliseconds.

11. A method for multicast service advertisement in a communication system, comprising:

establishing a link layer protocol between subscriber stations belonging to a multicast group and an entity accessing a network; and

communicating the multicast service announcement over the link layer protocol;

wherein, the establishing of the link layer protocol comprises the following steps:

including an indicator into a predetermined time slot on a first channel; and

if the multicast group service announcement is indicated by the indicator, a link layer protocol setup request is included into a message communicated in a time slot on a second channel, the second time slot corresponding to a predetermined time slot on the first channel.

12. The method of claim 11, wherein the step of including an indicator into the predetermined time slot comprises:

determining a broadcast paging cycle; and

an indicator is included into the nth slot of each broadcast paging cycle.

13. The method of claim 11, wherein including an indicator into the nth slot of each broadcast paging cycle comprises: the indicator is included into the first slot of each broadcast paging cycle.

14. The method of claim 11, wherein the step of including a link layer protocol setup request into a message communicated in a time slot on the second channel comprises:

a multicast service announcement is included into a slot on the second channel that is offset from a predetermined slot on the first channel by a predetermined interval.

15. A method for multicast service announcement in a communication system, comprising:

receiving a multicast service announcement on the link layer protocol;

wherein the step of establishing a link layer protocol comprises:

decoding an indicator from a predetermined time slot on a first channel; and

if the link layer protocol setup request is indicated by the indicator, the link layer protocol setup request in a time slot on the second channel, the time slot corresponding to a predetermined time slot on the first channel, is decoded.

16. The method of claim 15, wherein the step of decoding an indicator from a predetermined slot on the first channel comprises:

determining a broadcast paging cycle; and

an indicator in the nth slot of each broadcast paging cycle is decoded.

17. The method of claim 16, wherein the step of decoding the indicator in the nth slot of each broadcast paging cycle comprises:

an indicator in a first slot of each broadcast paging cycle is decoded.

18. The method of claim 15, wherein the time slot is offset from a predetermined time slot on the first channel by a predetermined interval.

19. A method for multicast service advertisement in a communication system, comprising:

communicating the multicast service announcement over the link layer protocol;

wherein the step of establishing a link layer protocol comprises:

including an indicator into a first time slot on a first channel; and

if the link layer protocol setup request is indicated by the indicator, a link layer protocol setup request is included into a second time slot on the second channel, the second time slot corresponding to the first time slot.

20. The method of claim 19, wherein the step of including an indicator into the first time slot comprises:

determining a broadcast paging cycle; and

21. The method of claim 20, wherein determining the first time slot according to the multicast paging cycle and a multicast group identifier comprises:

the first time slot is set to the output value of the hash function.

22. The method of claim 19 wherein the second time slot is offset from the first time slot by a predetermined interval.

23. The method of claim 22 wherein the second time slot is offset from the first time slot by 100 milliseconds.

24. A method for multicast service announcement in a communication system, comprising:

receiving a multicast service announcement on the link layer protocol;

decoding an indicator from a first slot on a first channel; and

if the link layer protocol setup request is indicated by the indicator, decoding a link layer protocol setup request included in a second time slot on the second channel, the second time slot corresponding to the first time slot.

25. The method of claim 24, wherein decoding an indicator from a first slot on a first channel comprises:

determining a broadcast paging cycle; and

26. The method of claim 25, wherein determining the first time slot according to the multicast paging cycle and a multicast group identifier comprises:

the first time slot is set to the output value of the hash function.

27. The method of claim 24, wherein the second time slot is offset from the first time slot by a predetermined interval.

28. The method of claim 27, wherein the second time slot is offset from the first time slot by 100 milliseconds.

29. An apparatus for multicast service advertisement in a communication system, comprising:

means for including an indicator into a first time slot on a first channel; and

means for including the multicast service announcement in a message communicated in a second slot on the second channel, the second slot corresponding to the first slot, if the multicast group service announcement is indicated by the indicator.

30. The apparatus of claim 29, wherein means for including an indicator into a first time slot comprises:

means for determining a broadcast paging cycle; and

means for determining the first time slot according to the multicast paging cycle and a multicast group identifier.

31. The apparatus of claim 30, wherein means for determining the first time slot according to the multicast paging cycle and a multicast group identifier comprises:

means for inputting a multicast paging cycle and a multicast group identifier into a hash function; and

means for setting the first time slot to be the output value of the hash function.

32. The apparatus of claim 29, wherein the second time slot is offset from the first time slot by a predetermined interval.

33. The apparatus of claim 32, wherein the second time slot is offset from the first time slot by 100 milliseconds.

34. An apparatus for multicast service notification for a subscriber station in a communication system, comprising:

means for decoding an indicator from a first slot on a first channel; and

means for decoding the multicast service announcement in a second slot on the second channel if the multicast service announcement is indicated by the indicator, the second slot corresponding to the first slot.

35. The apparatus of claim 34, wherein means for decoding an indicator from a first slot on a first channel comprises:

means for determining a broadcast paging cycle; and

means for determining a first slot according to the multicast paging cycle and a multicast group identifier.

36. The apparatus of claim 35, wherein means for determining the first time slot according to the multicast paging cycle and a multicast group identifier comprises:

37. The apparatus of claim 34, wherein the second time slot is offset from the first time slot by a predetermined interval.

38. The apparatus of claim 37, wherein the second time slot is offset from the first time slot by 100 milliseconds.

39. An apparatus for multicast service advertisement in a communication system, comprising:

means for establishing a link layer protocol between subscriber stations belonging to a multicast group and an entity accessing a network; and

means for communicating the multicast service advertisement over the link layer protocol;

wherein the means for establishing a link layer protocol comprises:

means for including an indicator into a predetermined time slot on a first channel; and

means for including a link layer protocol setup request into a message communicated in a slot on a second channel, the second slot corresponding to a predetermined slot on the first channel, if the multicast group service announcement is indicated by the indicator.

40. The apparatus of claim 39, wherein the means for including an indicator into a predetermined time slot comprises:

means for determining a broadcast paging cycle; and

means for including an indicator into the nth slot of each broadcast paging cycle.

41. The apparatus of claim 39, wherein means for including an indicator into an nth slot of each broadcast paging cycle comprises: means for including the indicator into the first slot of each broadcast paging cycle.

42. The apparatus of claim 39, wherein the means for including a link layer protocol setup request into the message communicated in a time slot on the second channel comprises:

means for including a multicast service announcement into a slot on the second channel, the slot being offset from a predetermined slot on the first channel by a predetermined interval.

43. An apparatus for multicast service advertisement in a communication system, comprising:

means for receiving a multicast service advertisement on the link layer protocol;

wherein the means for establishing a link layer protocol comprises:

means for decoding an indicator from a predetermined time slot on a first channel; and

means for decoding a link layer protocol setup request in a time slot on the second channel, the time slot corresponding to a predetermined time slot on the first channel, if the link layer protocol setup request is indicated by the indicator.

44. The apparatus of claim 43, wherein means for decoding an indicator from a predetermined slot on a first channel comprises:

means for determining a broadcast paging cycle; and

means for decoding the indicator in the nth slot of each broadcast paging cycle.

45. The apparatus of claim 44, wherein means for decoding the indicator in the nth slot of each broadcast paging cycle comprises:

means for decoding an indicator in a first slot of each broadcast paging cycle.

46. The method of claim 43, wherein the time slot is offset from a predetermined time slot on the first channel by a predetermined interval.

47. An apparatus for multicast service advertisement in a communication system, comprising:

wherein the means for establishing a link layer protocol comprises:

means for including an indicator into a first time slot on a first channel; and

means for including a link layer protocol setup request into a second time slot on the second channel, the second time slot corresponding to the first time slot, if the link layer protocol setup request is indicated by the indicator.

48. The apparatus as claimed in claim 47, wherein the means for including an indicator into the first time slot comprises:

means for determining a broadcast paging cycle; and

49. The apparatus as claimed in claim 48 wherein said means for determining said first time slot according to said multicast paging cycle and a multicast group identifier comprises:

50. The apparatus of claim 47 wherein the second time slot is offset from the first time slot by a predetermined interval.

51. The apparatus of claim 50 wherein the second time slot is offset from the first time slot by 100 milliseconds.

52. An apparatus for multicast service advertisement in a communication system, comprising:

means for decoding an indicator from a first slot on a first channel; and

means for decoding a link layer protocol setup request included in a second time slot on the second channel, the second time slot corresponding to the first time slot, if the link layer protocol setup request is indicated by the indicator.

53. The apparatus of claim 52, wherein means for decoding an indicator from a first slot on a first channel comprises:

means for determining a broadcast paging cycle; and

54. The apparatus of claim 53, wherein means for determining the first time slot according to the multicast paging cycle and a multicast group identifier comprises:

55. The apparatus of claim 52, wherein the second time slot is offset from the first time slot by a predetermined interval.

56. The apparatus of claim 55, wherein the second time slot is offset from the first time slot by 100 milliseconds.