Reliable cooperative multicasting for MBS WiMAX traffic

Cooperative multicast communication techniques for emerging broadband multimedia services over WiMAX reduces network resource consumption, by broadcasting the data simultaneously to multiple users independently of their number, on a common shared downlink channel. Users distributed around the cell face different channel conditions due to fading, user location, mobility, and other related issues. Recently, several schemes were reported in the literature that attempt to introduce cooperative multicasting reliably and efficiently, some of which utilize subscribers with good-channel as Relay Agents (RAs) to provide coverage for subscribers suffering bad-channel conditions but ignore the large amount of energy consumed in the process. In this paper, we propose energy-efficient cooperative multicasting schemes by properly selecting RAs based on their location, channel condition and coverage. By exploiting the channel state information (CSI) and the location based service (LBS), three protocols based on nearest neighbor, transmission distance and subscriber-subscriber interlink instantaneous CSI were proposed and implemented in order to improve the system’s energy consumption performance. Number of RAs was varied according to channel conditions on a frame-per-frame basis. This approach considerably reduces the amount of energy consumed as proven by analysis and simulation models, providing a lower cost coverage solution with no dereliction in achieved throughput.