Power allocation for nonregenerative OFDM relay links with outdated channel knowledge

This paper investigates the power allocation problem in a two-hop OFDM relay link with a nonregenarative relay where the available channel state information (CSI) is an outdated version of the actual instantaneous CSI. A power allocation method is proposed to maximize the expected capacity, assuming that the correlation between the outdated and instantaneous CSI is known. The performance is compared with that of the baseline method, where the power allocation is performed solely based on the outdated CSI. Results confirm that the proposed method outperforms the baseline method when the available CSI is highly outdated.