Optimized Selective OFDMA in multihop network

Selective OFDMA is a powerfull relaying technique with subcarrier based selection. This scheeme has a high potential to considerably improve the performance of cooperative OFDM systems. However, in practice, the implementation of this technique may suffer from multiple problems caused by the separation of the subcarriers from each other´s. In this Contribution, we propose a new selection scheme denoted “Optimized Selective OFDMA” that approaches selective OFDMA performance in terms of outage probability while reducing its synchronization problems that may be caused by the subcarriers separation. The outage probability and diversity order of the proposed scheme are derived. The number of the used paths is also analyzed. We proved that for high SNR, the introduced scheme gives exactly the same performance of selective OFDMA with only one path for all the subcarriers.