Joint Power Allocation and Subcarrier Pairing for Cooperative OFDM AF Multi-Relay Networks

For conventional subcarrier pairing scheme in cooperative orthogonal frequency division multiplexing amplify-and-forward multi-relay networks, to avoid interference, each subcarrier pair (SP) is assigned to only one relay, over a specific subcarrier, the destination receives signals transmitted from only one relay. In this letter, we propose to assign each SP to all the relays. Thus, over a specific subcarrier, the destination receives signals transmitted from all the relays. We propose a joint power allocation and subcarrier pairing scheme which maximizes the transmission rate subject to total network power constraint. The problem is simplified and solved by using dual method.