SWITCHING CARRIERS TO JOIN A MULTICAST SESSION WITHIN A WIRELESS COMMUNICATIONS NETWORK

• US 20090252076A1
• Filed: 03/26/2009
• Published: 10/08/2009
• Est. Priority Date: 04/02/2008
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: SONG, BONGYONG
• Granted Patent: US 8,654,690 B2
• Time in Patent Office: Days
• US Class Current: 370/312
• CPC Class Codes: H04W 60/00 Affiliation to network, e.g. registration; Terminating affiliation with the network, e.g. de-registration
• CPC Class Codes: H04W 72/0453 Resources in frequency domain, e.g. a carrier in FDMA
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal
• CPC Class Codes: H04W 72/30 Resource management for broadcast services
• CPC Class Codes: H04W 76/15 Setup of multiple wireless link connections

Abstract

Embodiments are directed to supporting a multicast session in a wireless communications network are provided. A request to register for an announced multicast session (e.g., a push to talk (PTT) session) is sent from an access terminal to an access network. The access terminal has a traffic channel on a first carrier. The access network determines whether the announced multicast session is being carried on the first carrier. The access network transmits a traffic channel assignment message allocating the access terminal a traffic channel on a second carrier if the determining step determines that the given multicast session is not being carried on the first carrier and is being carried on the second carrier. Thus, the access terminal need not send a connection request to be allocated a traffic channel on the second carrier, thereby reducing a channel outage during the carrier switch.

Claims

1. A method of supporting a multicast session in a wireless communications network, comprising:

receiving, from an access terminal, a request to register for a given multicast session, the access terminal being allocated a traffic channel on a first carrier;

determining whether the given multicast session is being carried on the first carrier; and

transmitting a traffic channel assignment message allocating the access terminal a traffic channel on a second carrier if the determining step determines that the given multicast session is not being carried on the first carrier and is being carried on the second carrier.

2. The method of claim 1, further comprising:

transmitting to the access terminal, after the transmission of the traffic channel assignment message, a scheduling message on the second carrier, the scheduling message identifying the given multicast session and indicating how multicast messages associated with the given multicast session can be decoded on a downlink channel of the second carrier.

3. The method of claim 2, wherein the scheduling message is a broadcast overhead message (BOM) that identifies the given multicast session by listing a broadcast and multicast service (BCMCS) flow identifier (ID) associated with the given multicast session, and the BOM further includes an interlace-multiplex (IM) pair and a transmission format associated with the listed BCMCS flow ID.

4. The method of claim 1, further comprising:

transmitting multicast messages associated with the given multicast session on the second carrier at least within a serving sector of the access terminal.

5. The method of claim 1, wherein the request to register to the given multicast session is received from the access terminal in response to a previously sent announce message on the first carrier that announces the given multicast session.

6. The method of claim 1, wherein the request to register to the given multicast session is received from the access terminal in response to a previously sent scheduling message on the first carrier that identifies the given multicast session and indicating that the given multicast session is being carried on the second carrier.

7. The method of claim 6, wherein the previously sent scheduling message is a broadcast overhead message (BOM) that identifies the given multicast session by listing a broadcast and multicast service (BCMCS) flow identifier (ID) associated with the given multicast session.

8. The method of claim 1, wherein the transmitting step transmits the traffic channel assignment message on the first carrier.

9. The method of claim 1, further comprising:

determining whether the second carrier includes at least one available traffic channel.

10. The method of claim 9, wherein the transmitting step is performed only after the determining step determines that the second carrier includes at least one available traffic channel.

11. The method of claim 1, further comprising:

transmitting to the access terminal, before the transmission of the traffic channel assignment message, a scheduling message on the first carrier, the scheduling message identifying the given multicast session and indicating that the given multicast session is being carried on the second carrier.

12. The method of claim 11, wherein the receiving step receives the request to register in response to the scheduling message.

13. The method of claim 1, wherein the transmitting step is only performed if the determining step determines that the given multicast session is not being carried on the first carrier and is being carried on the second carrier.

14. The method of claim 1, wherein the request to register to the given multicast session is a broadcast and multicast service (BCMCS) flow registration message.

15. The method of claim 1, wherein the request to register for the given multicast session is interpreted as a request to perform the transmitting step such that the access terminal need not send a connection request to be allocated the traffic channel on the second carrier.

16. A method of switching carriers to participate in a multicast session in a wireless communications network, comprising:

sending, from an access terminal, a request to register for a given multicast session, the access terminal being allocated a traffic channel on a first carrier; and

receiving a traffic channel assignment (TCA) message allocating the access terminal a traffic channel on a second carrier if the given multicast session is not being carried on the first carrier and is being carried on the second carrier.

17. The method of claim 16, further comprising:

tuning to the second carrier.

18. The method of claim 17, further comprising:

receiving a scheduling message on the second carrier, the scheduling message identifying the given multicast session and indicating how multicast messages associated with the given multicast session can be decoded on a downlink channel of the second carrier.

19. The method of claim 18, wherein the scheduling message is a broadcast overhead message (BOM) that identifies the given multicast session by listing a broadcast and multicast service (BCMCS) flow identifier (ID) associated with the given multicast session, and the BOM further includes an interlace-multiplex (IM) pair and a transmission format associated with the listed BCMCS flow ID.

20. The method of claim 17, further comprising:

transitioning a communication session at the access terminal carried over the traffic channel on the first carrier to the traffic channel on the second channel, the traffic channel on the second channel being allocated by the received TCA message.

21. The method of claim 18, further comprising:

receiving multicast messages associated with the given multicast session on the downlink channel of the second carrier; and

decoding the received multicast messages based on the received scheduling message.

22. The method of claim 16, wherein the sending step is performed in response to a previously received announce message on the first carrier that announces the given multicast session.

23. The method of claim 16, wherein the sending step is performed in response to a previously received scheduling message on the first carrier that identifies the given multicast session and that indicates the given multicast session is being carried on the second carrier.

24. The method of claim 23, wherein the scheduling message is a broadcast overhead message (BOM) that identifies the given multicast session by listing a broadcast and multicast service (BCMCS) flow identifier (ID) associated with the given multicast session.

25. The method of claim 16, wherein the TCA message is received on the first carrier.

26. The method of claim 16, further comprising:

receiving a scheduling message on the first carrier that identifies the given multicast session and that indicates the given multicast session is being carried on the second carrier, before receiving the TCA message.

27. The method of claim 26, wherein the sending step sends the request to register in response to the received scheduling message.

28. The method of claim 16, further comprising:

starting a timer having a given timer period after the sending step.

29. The method of claim 28, further comprising:

releasing the traffic channel on the first carrier before receiving the TCA message allocating the traffic channel on the second carrier if the timer expires before receiving the TCA message.

30. The method of claim 28, wherein the TCA message allocating the traffic channel on the second carrier is received before the timer expires.

31. The method of claim 30, further comprising:

tuning to the second carrier; and

transitioning a communication session at the access terminal carried over the traffic channel on the first carrier to the traffic channel on the second channel.

32. The method of claim 16, wherein the request to register to the given multicast session is a broadcast and multicast service (BCMCS) flow registration message.

33. The method of claim 16, wherein the request to register for the given multicast session is interpreted, at an access network, as a request to perform the first transmitting step such that the access terminal need not send a connection request to be allocated the traffic channel on the second carrier.

34. An access network in a wireless communications network, comprising:

means for receiving, from an access terminal, a request to register for a given multicast session, the access terminal being allocated a traffic channel on a first carrier;

means for determining whether the given multicast session is being carried on the first carrier; and

means for transmitting a traffic channel assignment message allocating the access terminal a traffic channel on a second carrier if the means for determining determines that the given multicast session is not being carried on the first carrier and is being carried on the second carrier.

35. The access network of claim 34, further comprising:

means for transmitting to the access terminal, after the transmission of the traffic channel assignment message, a scheduling message on the second carrier, the scheduling message identifying the given multicast session and indicating how multicast messages associated with the given multicast session can be decoded on a downlink channel of the second carrier.

36. The access network of claim 34, further comprising:

means for transmitting multicast messages associated with the given multicast session on the second carrier at least within a serving sector of the access terminal.

37. The access network of claim 34, further comprising:

means for transmitting to the access terminal, before the transmission of the traffic channel assignment message, a scheduling message on the first carrier, the scheduling message identifying the given multicast session and indicating that the given multicast session is being carried on the second carrier.

38. An access terminal in a wireless communications network, comprising:

means for sending a request to register for a given multicast session, the access terminal being allocated a traffic channel on a first carrier; and

means for receiving a traffic channel assignment (TCA) message allocating the access terminal a traffic channel on a second carrier if the given multicast session is not being carried on the first carrier and is being carried on the second carrier.

39. The access terminal of claim 38, further comprising:

means for tuning to the second carrier.

40. The access terminal of claim 39, further comprising:

means for transitioning a communication session at the access terminal carried over the traffic channel on the first carrier to the traffic channel on the second channel, the traffic channel on the second channel being allocated by the received TCA message.

41. The access terminal of claim 39, further comprising:

means for receiving a scheduling message on the second carrier, the scheduling message identifying the given multicast session and indicating how multicast messages associated with the given multicast session can be decoded on a downlink channel of the second carrier.

42. The access terminal of claim 39, further comprising:

means for receiving multicast messages associated with the given multicast session on the downlink channel of the second carrier; and

means for decoding the received multicast messages based on the received scheduling message.

43. An access network in a wireless communications network, comprising:

logic configured to receive, from an access terminal, a request to register for a given multicast session, the access terminal being allocated a traffic channel on a first carrier;

logic configured to determine whether the given multicast session is being carried on the first carrier; and

logic configured to transmit a traffic channel assignment message allocating the access terminal a traffic channel on a second carrier if the logic configured to determine determines that the given multicast session is not being carried on the first carrier and is being carried on the second carrier.

44. The access network of claim 43, further comprising:

logic configured to transmit to the access terminal, after the transmission of the traffic channel assignment message, a scheduling message on the second carrier, the scheduling message identifying the given multicast session and indicating how multicast messages associated with the given multicast session can be decoded on a downlink channel of the second carrier.

45. The access network of claim 43, further comprising:

logic configured to transmit multicast messages associated with the given multicast session on the second carrier at least within a serving sector of the access terminal.

46. The access network of claim 43, further comprising:

logic configured to transmit to the access terminal, before the transmission of the traffic channel assignment message, a scheduling message on the first carrier, the scheduling message identifying the given multicast session and indicating that the given multicast session is being carried on the second carrier.

47. An access terminal in a wireless communications network, comprising:

logic configured to send a request to register for a given multicast session, the access terminal being allocated a traffic channel on a first carrier; and

logic configured to receive a traffic channel assignment (TCA) message allocating the access terminal a traffic channel on a second carrier if the given multicast session is not being carried on the first carrier and is being carried on the second carrier.

48. The access terminal of claim 47, further comprising:

logic configured to tune to the second carrier.

49. The access terminal of claim 48, further comprising:

logic configured to transition a communication session at the access terminal carried over the traffic channel on the first carrier to the traffic channel on the second channel, the traffic channel on the second channel being allocated by the received TCA message.

50. The access terminal of claim 48, further comprising:

logic configured to receive a scheduling message on the second carrier, the scheduling message identifying the given multicast session and indicating how multicast messages associated with the given multicast session can be decoded on a downlink channel of the second carrier.

51. The access terminal of claim 48, further comprising:

logic configured to receive multicast messages associated with the given multicast session on the downlink channel of the second carrier; and

logic configured to decode the received multicast messages based on the received scheduling message.

52. A computer-readable medium comprising instructions, which, when executed by an access network in a wireless communications network, cause the access network to perform operations, the instructions comprising:

program code to receive, from an access terminal, a request to register for a given multicast session, the access terminal being allocated a traffic channel on a first carrier;

program code to determine whether the given multicast session is being carried on the first carrier; and

program code to transmit a traffic channel assignment message allocating the access terminal a traffic channel on a second carrier if the program code to determine determines that the given multicast session is not being carried on the first carrier and is being carried on the second carrier.

53. The computer-readable medium of claim 52, further comprising:

logic configured to transmit to the access terminal, after the transmission of the traffic channel assignment message, a scheduling message on the second carrier, the scheduling message identifying the given multicast session and indicating how multicast messages associated with the given multicast session can be decoded on a downlink channel of the second carrier.

54. The computer-readable medium of claim 53, further comprising:

program code to transmit multicast messages associated with the given multicast session on the second carrier at least within a serving sector of the access terminal.

55. The computer-readable medium of claim 53, further comprising:

program code to transmit to the access terminal, before the transmission of the traffic channel assignment message, a scheduling message on the first carrier, the scheduling message identifying the given multicast session and indicating that the given multicast session is being carried on the second carrier.

56. A computer-readable medium comprising instructions, which, when executed by an access terminal in a wireless communications network, cause the access terminal to perform operations, the instructions comprising:

program code to send a request to register for a given multicast session, the access terminal being allocated a traffic channel on a first carrier; and

program code to receive a traffic channel assignment (TCA) message allocating the access terminal a traffic channel on a second carrier if the given multicast session is not being carried on the first carrier and is being carried on the second carrier.

57. The computer-readable medium claim 56, further comprising:

program code to tune to the second carrier.

58. The computer-readable medium of claim 57, further comprising:

program code to transition a communication session at the access terminal carried over the traffic channel on the first carrier to the traffic channel on the second channel, the traffic channel on the second channel being allocated by the received TCA message.

59. The computer-readable medium of claim 57, further comprising:

program code to receive a scheduling message on the second carrier, the scheduling message identifying the given multicast session and indicating how multicast messages associated with the given multicast session can be decoded on a downlink channel of the second carrier.

60. The computer-readable medium of claim 57, further comprising:

program code to receive multicast messages associated with the given multicast session on the downlink channel of the second carrier; and

program code to decode the received multicast messages based on the received scheduling message.