Khatri-Rao space-time codes

Space-time (ST) coding techniques exploit the spatial diversity afforded by multiple transmit and receive antennas to achieve reliable transmission in scattering-rich environments. ST block codes are capable of realizing full diversity and spatial coding gains at relatively low rates; ST trellis codes can achieve better rate-diversity tradeoffs at the cost of high complexity. On the other hand, V-BLAST supports high rates but has no built-in spatial coding and does not work well with fewer receive than transmit antennas. We propose a novel linear block-coding scheme based on the Khatri-Rao matrix product. The proposed scheme offers flexibility for achieving full-rate or full-diversity, or a desired rate-diversity tradeoff, and it can handle any transmit/receive antenna configuration or signal constellation. The proposed codes are shown to have numerous desirable properties, including guaranteed unique linear decodability, built-in blind channel identifiability, and efficient near-maximum likelihood decoding.