An efficient multiple relay selection scheme for wireless sensor networks under global power constraint

In this paper, we propose a multiple relay selection scheme, which allocates the global power optimally to best relays which are selected to maximize signal to noise (SNR) ratio. First, all available relays are sorted from the highest priority to the lowest priority to cooperate in transmission by using the idea of relay ordering. Then, the total relay power is allocated optimally to different sets of relays to maximize received SNR. Finally, a relay set which is resulted in the highest SNR subject to total relay power constraint is selected. Simulation results show that proposed scheme provides full diversity and considerably better performance than schemes assume all relay nodes participate with same global power constraint. In addition, less relays are engaged in transmission, while the relay selection scheme has linear complexity.