Patent ID: 7301914

Claim:
A method in a communication system that supports sending multicast messages from an access point (AP) to communication units (CUs) belonging to a plurality of multicast groups each having a multicast address, the method for selectively awakening the CUs belonging to a particular multicast group, the method comprising: conveying to the CUs of the plurality of multicast groups, a first indication that the AP supports the method; receiving, by the AP, a multicast message directed to a receiving one of the plurality of multicast groups; determining, by the AP, that the CUs belonging to said receiving one of the plurality of multicast groups also support the method; signaling, by the AP, a second indication to selectively awaken the CUs belonging to said receiving one of the plurality of multicast groups; transmitting, by the AP, the multicast message to said receiving one of the plurality of multicast groups; allowing at least one CU not belonging to the receiving one of the plurality of multicast groups to remain asleep during said transmitting; receiving, by the AP, from a CU belonging to a multicast group, a first command to associate said multicast group with a private address associated with the CU for sending a unicast message; and associating, by the AP, said multicast group with said private address, in response to receiving said first command, and wherein said signaling comprises sending the second indication referring to said private address.