Optimal decoding for hard-decision forwarding aided cooperative spatial multiplexing systems

In this letter, the optimal decoding strategy for cooperative spatial multiplexing (CSM) aided systems is derived. In CSM systems, the multiple relay stations (RSs), which compose a virtual antenna array (VAA), independently decode the packets received from the mobile stations (MS) and forward them to the base station (BS). When the BS decodes the signal forwarded from the RSs, the potential decoding errors encountered at the RSs will result in erroneous forwarding, but their effects are mitigated by the proposed solution. Our simulation results show that when the relay link has a significantly higher signal-to-noise ratio than the direct link, the proposed decoding algorithm achieves an approximately 3 dB better performance than conventional CSM, which does not consider the deleterious effects of erroneous forwarding from the RSs.