Handing off an access terminal during a multicast session within a wireless communications system

Abstract

Methods and apparatuses for multicasting within a wireless communications system are disclosed. In one embodiment a method of multicasting within a wireless communications system operating in accordance with a given wireless communication protocol includes monitoring multicast messages associated with a given multicast session in a first sector. A handoff occurs from the first sector to a second sector. It is determined whether the second sector is transmitting multicast messages associated with the given multicast session. Then, based on the determination, a registration request for the given multicast session within the second sector is transmitted on a reverse link access channel in an earlier slot than a next designated slot for registration requests as defined by the wireless communication protocol.

1 . A method of multicasting within a wireless communications system operating in accordance with a given wireless communication protocol, comprising:
 monitoring multicast messages associated with a given multicast session in a first sector;   receiving a first scheduling message within the first sector that advertises the given multicast session as carried in the first sector and at least a second sector, and further indicates how an access terminal can tune to the given multicast session in the first and second sectors;   handing off from the first sector to the second sector;   determining, based on the first scheduling message, that the second sector is carrying the given multicast session;   refraining from transmitting a registration request for the given multicast session within the second sector based on the first scheduling message; and   attempting to monitor multicast messages associated with the given multicast session in the second sector.   
     
     
         2 . The method of  claim 1 , further comprising:
 receiving a second scheduling message within the second sector that advertises the given multicast session as carried in the second sector, and further indicates how an access terminal can tune to the given multicast session in the second.   
     
     
         3 . The method of  claim 2 , wherein the second scheduling message indicates at least one other neighboring target sector that is carrying the given multicast session on the same Interlace-Multiplex (IM) pair as the second sector. 
     
     
         4 . The method of  claim 3 , further comprising:
 establishing an initial list of sectors known to be carrying the given multicast session based on the first scheduling message;   updating, at the access terminal, the initial list of sectors known to be carrying the given multicast session based on the second scheduling message,   wherein, after the updating, the attempting includes attempting to soft combine multicast messages associated with the given multicast message that are received from the second sector and the at least one neighboring target sector.   
     
     
         5 . The method of  claim 1 , wherein the attempting continues until (i) the access terminal cannot decode multicast packets associated with the given multicast session, an application layer cannot sufficiently correct errors in the given multicast session or a packet error rate reaches an unacceptable level, or (ii) a second scheduling message is received within the second sector that advertises the given multicast session as carried in the second sector, and further indicates how an access terminal can tune to the given multicast session in the second sector. 
     
     
         6 . The method of  claim 1 , wherein the first scheduling message corresponds to a broadcast overhead message (BOM). 
     
     
         7 . A non-transitory computer-readable storage medium comprising instructions, which, when executed by at least one processor provide for multicasting within a wireless communications system operating in accordance with a given wireless communication protocol, the instructions comprising:
 instructions to monitor multicast messages associated with a given multicast session in a first sector;   instructions to receive a first scheduling message within the first sector that advertises the given multicast session as carried in the first sector and at least a second sector, and further indicates how an access terminal can tune to the given multicast session in the first and second sectors;   instructions to hand off from the first sector to the second sector;   instructions to determine, based on the first scheduling message, that the second sector is carrying the given multicast session;   instructions to refrain from transmitting a registration request for the given multicast session within the second sector based on the first scheduling message; and   instructions to attempt to monitor multicast messages associated with the given multicast session in the second sector.   
     
     
         8 . An apparatus configured for multicasting within a wireless communications system operating in accordance with a given wireless communication protocol, the apparatus comprising:
 logic configured to monitor multicast messages associated with a given multicast session in a first sector;   logic configured to receive a first scheduling message within the first sector that advertises the given multicast session as carried in the first sector and at least a second sector, and further indicates how an access terminal can tune to the given multicast session in the first and second sectors;   logic configured to hand off from the first sector to the second sector;   logic configured to determine, based on the first scheduling message, that the second sector is carrying the given multicast session;   logic configured to refrain from transmitting a registration request for the given multicast session within the second sector based on the first scheduling message; and   logic configured to attempt to monitor multicast messages associated with the given multicast session in the second sector.   
     
     
         9 . The non-transitory computer-readable storage medium of  claim 7 , further comprising:
 instructions to receive a second scheduling message within the second sector that advertises the given multicast session as carried in the second sector, and further indicates how an access terminal can tune to the given multicast session in the second.   
     
     
         10 . The non-transitory computer-readable storage medium of  claim 9 , wherein the second scheduling message indicates at least one other neighboring target sector that is carrying the given multicast session on the same Interlace-Multiplex (IM) pair as the second sector. 
     
     
         11 . The non-transitory computer-readable storage medium of  claim 10 , further comprising:
 instructions to establish an initial list of sectors known to be carrying the given multicast session based on the first scheduling message;   instructions to update, at the access terminal, the initial list of sectors known to be carrying the given multicast session based on the second scheduling message,   wherein, after the initial list of sectors is updated by the instructions to update, the instructions to attempt attempts to soft combine multicast messages associated with the given multicast message that are received from the second sector and the at least one neighboring target sector.   
     
     
         12 . The non-transitory computer-readable storage medium to of  claim 7 , wherein the instructions to attempt continue attempting to monitor until (i) the access terminal cannot decode multicast packets associated with the given multicast session, an application layer cannot sufficiently correct errors in the given multicast session or a packet error rate reaches an unacceptable level, or (ii) a second scheduling message is received within the second sector that advertises the given multicast session as carried in the second sector, and further indicates how an access terminal can tune to the given multicast session in the second sector. 
     
     
         13 . The non-transitory computer-readable storage medium of  claim 7 , wherein the first scheduling message corresponds to a broadcast overhead message (BOM). 
     
     
         14 . The apparatus of  claim 8 , further comprising:
 logic configured to receive a second scheduling message within the second sector that advertises the given multicast session as carried in the second sector, and further indicates how an access terminal can tune to the given multicast session in the second.   
     
     
         15 . The apparatus of  claim 14 , wherein the second scheduling message indicates at least one other neighboring target sector that is carrying the given multicast session on the same Interlace-Multiplex (IM) pair as the second sector. 
     
     
         16 . The apparatus of  claim 15 , further comprising:
 logic configured to establish an initial list of sectors known to be carrying the given multicast session based on the first scheduling message;   logic configured to update, at the access terminal, the initial list of sectors known to be carrying the given multicast session based on the second scheduling message,   wherein, after the initial list of sectors is updated by the logic configured to update, the logic configured to attempt attempts to soft combine multicast messages associated with the given multicast message that are received from the second sector and the at least one neighboring target sector.   
     
     
         17 . The apparatus of  claim 8 , wherein the logic configured to attempt continues to attempt to monitor until (i) the access terminal cannot decode multicast packets associated with the given multicast session, an application layer cannot sufficiently correct errors in the given multicast session or a packet error rate reaches an unacceptable level, or (ii) a second scheduling message is received within the second sector that advertises the given multicast session as carried in the second sector, and further indicates how an access terminal can tune to the given multicast session in the second sector. 
     
     
         18 . The apparatus of  claim 8 , wherein the first scheduling message corresponds to a broadcast overhead message (BOM). 
     
     
         19 . The method of  claim 1 , further comprising:
 starting a timer after handing off from the first sector to the second sector; and   in response to the attempting failing to monitor the multicast messages associated with the given multicast session in the second sector prior to expiration of the timer, stopping the refraining by transmitting the registration request for the given multicast session within the second sector.   
     
     
         20 . The method of  claim 1 , wherein, based upon the first scheduling message, the attempting occurs after the handoff without waiting for any scheduling messages to be received within the second sector.