Adaptive modulation for OFDM based multi-hop wireless networks

In a cellular network with relays, the mobile station (MS) can benefit from both coverage extension and throughput enhancement. To improve the throughput of such cellular multi-hop networks, we propose an adaptive modulation (AM) combined with orthogonal frequency division multiplexing (OFDM). Using AM with OFDM enables the transmitter to change the order of the modulation on each subcarrier separately depending on channel conditions resulting in a higher throughput in the network. Simulation results show that our proposed scheme can significantly improve the end-to-end throughput.