Energy efficient cooperative communication in single frequency networks

Cooperative multicast communication techniques for emerging broadband multimedia services, such as IPTV, over WiMAX channels reduces the network resource consumption, by multicasting the data once to multiple users simultaneously independently of their number, using a common shared downlink channel. Users distributed around the cell face different channel conditions due to fading, user location, mobility, and other related characteristics. Several schemes were reported in the literature that attempt to introduce cooperative multicasting, some of which are designed to reliably and efficiently utilize subscribers with good-channel as relaying subscriber stations to provide coverage for subscribers with bad-channel but fail to consider the huge amount of energy consumed in the process. In this paper, we propose an energy-efficient cooperative multicasting scheme by properly selecting relay agents (RAs) based on their location, channel condition and coverage. By exploiting the channel state information (CSI) and the location based service (LBS), a nearest neighbor protocol and two further optimized versions of it based on RA´s transmission distance and instantaneous CSI were simulated and studied in the context of WiMAX single frequency networks. They were found to considerably reduce the amount of energy consumed, providing a lower cost coverage solution with no dereliction in achieving high throughput for all multicast group members.