Adaptive power allocation scheme for energy efficient OFDMA relay networks

An adaptive power allocation algorithm called two-hop power allocation (THPA) is proposed to guarantee two-hop data rate balance in regenerative OFDM relay systems. The aim of this algorithm is power efficiency at the transmission node. The base station (BS) or relay station (RS) adjust power adaptively in terms of the difference between the first hop link data rate and the second hop link data rate of each RS. The transmission power on the link with the larger data rate will be reduced while the transmission power on the other link remaining the same. In this way, the data rate on the two hops of one RS will be matched and the total transmission power will be reduced. The simulation with different RS location is given and it is shown that the THPA algorithm can reduce the power of BS and RS efficiently while not affecting the system throughput and user fairness.