Energy efficient cooperative multicast based on relay selection and power allocation

Aimed at the problem that system energy consumption of traditional cooperative multicast is becoming larger with the increase of the number of users, a method of energy efficient relay selection is proposed. By using channel state information (CSI) among users, each user with poor channel condition selected a user, who had the best channel condition with it, as a relay, the selected user had decoded data correctly. Then two different approaches were taken to optimally allocate relays´ power. Results show that energy efficient cooperation reduces energy consumption while ensuring the fairness compared to traditional cooperation; besides, energy efficient cooperation of improved power allocation reduces the computational complexity compared to energy efficiency cooperation based on approximate optimal relays power allocation.