Multicasting within a wireless communications system

Abstract

An access network determines to transmit multicast messages on a downlink shared channel. The access network receives a multicast registration message and a traffic channel request from at least one access terminal. The access network assigns a traffic channel to the at least one access terminal, and transmits the multicast messages on the downlink shared channel. In another example, the access network can determine a channel type upon which the support a multicast session, can indicate the channel type selection to the at least one access terminal in an announce message and can then transmit the multicast messages for the multicast session on the selected channel type. The at least one access terminal receives the announce message, requests a traffic channel and receives a traffic channel assignment, registers to the multicast session and monitors the downlink shared channel for multicast messages.

1 . A method of multicasting within a wireless communications system, comprising:
 receiving an announce message for announcing a multicast session to a plurality of multicast group members;   determining a channel type upon which to support the multicast session;   configuring the announce message to indicate the determined channel type;   transmitting the configured announce message to the plurality of multicast group members within at least one of a plurality of sectors; and   transmitting multicast messages associated with the announced multicast session on the determined channel type only within sectors that are expected to include one or more of the plurality of multicast group members.   
     
     
         2 . The method of  claim 1 , wherein determining comprises selecting a downlink shared channel as the channel type upon which to support the multicast session. 
     
     
         3 . The method of  claim 2 , wherein the downlink shared channel is a downlink control channel or a downlink broadcast channel. 
     
     
         4 . The method of  claim 1 , wherein configuring comprises generating a supplemental message for indicating the determined channel type, and the transmission of the configured announce message corresponds to a transmission of the supplemental message along with the announce message. 
     
     
         5 . The method of  claim 1 , wherein the determining is performed on a per-subnet basis, such that different subnets are capable of selecting different channel types upon which to support the multicast session. 
     
     
         6 . The method of  claim 5 , wherein a first subnet performing the determining determines to support the multicast session on a downlink shared channel and a second subnet determines to support the multicast session on a downlink broadcast channel. 
     
     
         7 . The method of  claim 1 ,
 wherein the determining is performed independently for each of a plurality of groups of sectors within a given subnet,   wherein a first instance of the determining determines to support the multicast session on a downlink shared channel for a first group of sectors within the given subnet, and   wherein a second instance of the determining determines to support the multicast session on a downlink broadcast channel for a second group of sectors within the given subnet.   
     
     
         8 . The method of  claim 1 , further comprising:
 receiving a multicast session registration from each of the one or more multicast group members to request registration to the announced multicast session; and   if the determining determines to support the multicast session on a downlink shared channel, receiving a traffic channel request from each of the one or more multicast group members, and assigning a downlink traffic channel to each of the one or more multicast group members,   wherein the multicast messages are transmitted, on the downlink shared channel, only in sectors including the one or more multicast group members from which the multicast session registrations are received.   
     
     
         9 . An access network within a wireless communications system, comprising:
 logic configured to receive an announce message for announcing a multicast session to a plurality of multicast group members;   logic configured to determine a channel type upon which to support the multicast session;   logic configured to configure the announce message to indicate the determined channel type;   logic configured to transmit the configured announce message to the plurality of multicast group members within at least one of a plurality of sectors; and   logic configured to transmit multicast messages associated with the announced multicast session on the determined channel type only within sectors that are expected to include one or more of the plurality of multicast group members.   
     
     
         10 . A non-transitory computer-readable storage medium comprising instructions encoded thereon, which, when executed by an access network within a wireless communications system, cause the access network to perform operations, the instructions comprising:
 program code to receive an announce message for announcing a multicast session to a plurality of multicast group members;   program code to determine a channel type upon which to support the multicast session;   program code to configure the announce message to indicate the determined channel type;   program code to transmit the configured announce message to the plurality of multicast group members within at least one of a plurality of sectors; and   program code to transmit multicast messages associated with the announced multicast session on the determined channel type only within sectors that are expected to include one or more of the plurality of multicast group members.   
     
     
         11 . The access network of  claim 9 , wherein the logic configured to determine comprises logic configured to select a downlink shared channel as the channel type upon which to support the multicast session. 
     
     
         12 . The access network of  claim 9 , wherein the logic configured to determine generates a supplemental message for indicating the determined channel type, and the transmission of the configured announce message corresponds to a transmission of the supplemental message along with the announce message. 
     
     
         13 . The access network of  claim 9 , wherein the logic configured to determine determines the channel type on a per-subnet basis, such that different subnets are capable of selecting different channel types upon which to support the multicast session. 
     
     
         14 . The access network of  claim 9 ,
 wherein the logic configured to determine determines the channel type independently for each of a plurality of groups of sectors within a given subnet,   wherein the logic configured to determine determines to support the multicast session on a downlink shared channel for a first group of sectors within the given subnet, and   wherein the logic configured to determine determines to support the multicast session on a downlink broadcast channel for a second group of sectors within the given subnet.   
     
     
         15 . The access network of  claim 9 , further comprising:
 logic configured to receive a multicast session registration from each of the one or more multicast group members to request registration to the announced multicast session; and   logic configured to receive, if the logic configured to determine determines to support the multicast session on a downlink shared channel, a traffic channel request from each of the one or more multicast group members, and to assign a downlink traffic channel to each of the one or more multicast group members,   wherein the multicast messages are transmitted, on the downlink shared channel, only in sectors including the one or more multicast group members from which the multicast session registrations are received.   
     
     
         16 . The non-transitory computer-readable storage medium of  claim 10 , wherein the program code to determine comprises program code to select a downlink shared channel as the channel type upon which to support the multicast session. 
     
     
         17 . The non-transitory computer-readable storage medium of  claim 10 , wherein the program code to determine generates a supplemental message for indicating the determined channel type, and the transmission of the configured announce message corresponds to a transmission of the supplemental message along with the announce message. 
     
     
         18 . The non-transitory computer-readable storage medium of  claim 10 , wherein the program code to determine determines the channel type on a per-subnet basis, such that different subnets are capable of selecting different channel types upon which to support the multicast session. 
     
     
         19 . The non-transitory computer-readable storage medium of  claim 10 ,
 wherein the program code to determine determines the channel type independently for each of a plurality of groups of sectors within a given subnet,   wherein the program code to determine determines to support the multicast session on a downlink shared channel for a first group of sectors within the given subnet, and   wherein the program code to determine determines to support the multicast session on a downlink broadcast channel for a second group of sectors within the given subnet.   
     
     
         20 . The non-transitory computer-readable storage medium of  claim 10 , further comprising:
 program code to receive a multicast session registration from each of the one or more multicast group members to request registration to the announced multicast session; and   program code to receive, if the program code to determine determines to support the multicast session on a downlink shared channel, a traffic channel request from each of the one or more multicast group members, and to assign a downlink traffic channel to each of the one or more multicast group members,   wherein the multicast messages are transmitted, on the downlink shared channel, only in sectors including the one or more multicast group members from which the multicast session registrations are received.