Maximization of Energy Efficiency for Multi-Relay Cooperative System employing AF Protocol

Abstract

To maximize the system capacity in the multi-relay assisted cooperative network system, an energy efficient resources allocation scheme is presented in this paper. Under the total power constraint, the energy efficiency problem is modeled as the standard convex optimization, where the Karush-Kuhn-Tucher (KKT) condition is used to derive the total power allocation at each relay node. To compute the efficiency of the proposed algorithm, two power allocation strategies are compared for different number base stations at various signal-to-noise ratio (SNR). In optimal or equal power allocation, each relay use optimal power while in equal power allocation strategy, all relays would use the maximum available transmit power. Total power and per-relay power constraints are used to limit the maximum transmit power. For different number of relays stations, symbol error rate (SER) is also computed and compared for both optimal and equal power allocation.