Method and apparatus for multicast tree management in multi-hop relay communication system

1. A method in a wireless multi-hop relay network, said method comprising:

receiving multiple requests for a multicast service;

generating parameters associated with binding paths to a multicast tree to provide said requested multicast service, wherein parameters include a multicast connection identification; and

binding said paths to said multicast tree using said multicast connection identification, wherein said binding further comprises one of unicasting and multicasting a first message including said generated parameters to a relay station along said paths, wherein said parameters also include parameters for said multicast connection identification, a number of paths to which said multicast connection identification is to be bound and a list of paths to which said multicast connection identification is to be bound.

2. The method according to claim 1 , further comprising:

determining if said requests for multicast service can be accepted;

determining if a multicast tree identification has already been assigned, if said requests for multicast service can be accepted;

determining if all paths are already in a multicast tree, if said multicast tree identification has already been assigned;

updating tree information for all paths already in said multicast tree;

updating tree information for paths in said multicast tree; and

receiving a second message from said relay station.

3. The method according to claim 2 , further comprising sending a third message to said relay station for forwarding along all paths that have been bound to said multicast connection identification accepting said request for multicast service.

4. The method according to claim 2 , further comprising sending a third message to said relay station for forwarding along all paths that have not been bound to said multicast connection identification denying said request for multicast service.

5. The method according to claim 2 , further comprising denying said request for multicast service, if said multicast service cannot be accepted.

6. The method according to claim 2 , further comprising:

assigning said multicast tree identification, if said multicast tree identification was not already assigned; and

creating said multicast tree.

7. The method according to claim 1 , wherein said method is performed in a multicast relay base station.

8. The method according to claim 1 , further comprising:

receiving a multicast tree identification with said requests for multicast service;

binding said multicast tree identification to paths satisfying a quality of service level for said multicast tree identification; and

transmitting a first message to a multi-hop relay base station.

9. The method according to claim 8 , wherein said first message is sent for paths for which a relay station that transmitted said first message is a leaf node.

10. The method according to claim 8 , further comprising:

determining if there are any paths that cannot satisfy said quality of service level of said multicast tree identification; and

transmitting said first message to said multicast relay base station along paths that cannot satisfy said quality of service level of said multicast tree identification.

11. The method according to claim 10 , further comprising:

determining if all paths have a same next relay station;

forwarding said first message to said same next relay station, if all paths have said same next relay station;

coding information including a multicast connection identification, parameters for said multicast connection identification, a number of paths to which said multicast connection identification is to be bound and a list of paths to which said multicast connection identification is to be bound into different data structures for paths having different next relay stations; and

transmitting different second messages along paths with different next relay stations.

12. The method according to claim 10 , further comprising multicasting a second message to a next relay station, if there are paths for which a relay station that transmitted said first message is not a leaf node.

13. The method according to claim 12 , further comprising:

determining if said relay station that transmitted said first message is on any of the paths specified in said request for multicast service;

dropping said request for multicast service, if said relay station is not on any of the paths specified in said request for multicast service; and

ignoring any paths to which said relay station is not on any of the paths specified in said request for multicast service.

14. The method according to claim 8 , wherein said method is performed by a relay station.

15. A method in a wireless multi-hop relay network, said method comprising:

receiving requests to delete multicast service from client devices served by multiple paths;

generating parameters associated with unbinding paths from a multicast tree to delete said multicast service, wherein parameters include a multicast connection identification; and

unbinding said paths from said multicast tree using said multicast connection identification, wherein said unbinding further comprises one of unicasting and multicasting a first message including said generated parameters to a relay station along said paths, wherein said parameters also include parameters for said multicast connection identification, a number of paths to which said multicast connection identification is to be unbound and a list of paths to which said multicast connection identification is to be unbound.

16. The method according to claim 15 , further comprising:

updating tree information for paths in a multicast tree;

determining if there are any paths that still have client devices requiring said multicast service; and

transmitting a second message to said relay station for forwarding along paths that still require said multicast service.

17. The method according to claim 16 , further comprising:

receiving said second message from said relay station;

deleting paths having no client devices still requiring said multicast service from said multicast tree; and

transmitting a third message to client devices that were using said deleted paths.

18. The method according to claim 15 , wherein said method is performed by a multicast relay base station.

19. The method according to claim 15 , further comprising:

generating parameters associated with unbinding paths for which a relay station that transmitted said first message is not a leaf node.

20. The method according to claim 19 , wherein said unbinding further comprises one of unicasting and multicasting a first message including said generated parameters to said relay station along said paths.

21. The method according to claim 20 , wherein said request to delete said multicast service includes a multicast tree identification.

22. The method according to claim 21 , further comprising:

unbinding said multicast tree identification from all paths specified in said requests to delete multicast service;

determining if there are any paths for which said relay station is a leaf node; and

transmitting a second message to a multicast relay base station for which said relay station is a leaf node.

23. The method according to claim 21 , further comprising:

determining if said relay station belongs to any of the paths specified in the requests to delete multicast service;

unbinding said multicast tree identification from all paths specified in said requests to delete multicast service;

determining if there are any paths for which said relay station is a leaf node; and

transmitting a second message to a multicast relay base station for which said relay station is a leaf node.

24. The method according to claim 19 , wherein said method is performed by said relay station.