Single parameter optimization approach to the optimal power allocation of OFDM relaying system

In this paper, we investigate the power allocation optimization problem for dual-hop nonregenerative OFDM relaying networks, where an aggregate power constraint is imposed on all relays. We first formulate the model into a single-parameter optimization problem, in which we found the related functions are monotonically decreasing. Then based on the monotonicity, we propose a bisection algorithm to solve the problem. We further illustrate that pairing of OFDM subcarriers will not provide performance gain when the aggregate power constraint is very large.