Throughput performance of incremental decode-and-forward using infra-structured relays and Adaptive Modulation and Coding

In this paper we investigate the combination of Adaptive Modulation and Coding (AMC) and Hybrid Automatic Re- peat reQuest (HARQ) techniques in an orthogonal cooperative scheme using infra-structured (fixed) relays. We consider realistic large scale and small scale path loss models, taking into account the antennas heights and the presence or not of line of sight (LOS). Results demonstrate that large gains in throughput can be obtained when the source and the relay are allowed to use different spectral efficiencies. Moreover, we also propose a discretized AMC scheme with only six levels, which achieves a performance close to optimum.