Performance of adaptive fuzzy spreading coded selection tree combining for 2-D spreading OFCDM communication systems

In this paper, to compromise between the diversity gain and the multiple access interference (MAI), we propose a selection tree to choose a suitable combining scheme for 2-D spreading orthogonal frequency coded division multiplexing (OFCDM) communication system. Simulation results show that the proposed selection tree adaptive combining (STAC) scheme can not only suppress the MAIs induced by the non-orthogonality for heavy system load (SL) but also exploit the diversity gain for light system load over time and frequency selective fading channels. Moreover, we propose an adaptive fuzzy-based spreading coded (AFSC) selection tree combining scheme to further exploit the benefit of frequency and time diversity gain.