Throughput performance of incremental decode-and-forward using infra-structured relays and rate allocation

In this paper we investigate the combination of rate allocation (RA) and Hybrid Automatic Repeat reQuest (HARQ) techniques in an orthogonal cooperative scheme using 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 and coverage area can be obtained when the source and the relay are allowed to use different spectral efficiencies. Moreover, we also propose a discretized RA scheme with only six levels, which achieves a performance close to optimum.