Adaptive coding and modulation in MIMO OFDMA systems

Adaptive coding and modulation are well known techniques for enhancing the performance of systems transmitting over quasi-static fading channels. Especially their application in OFDM based systems promises gains in spectral efficiency. In former work we presented an efficient method for the joint optimization of code rate and modulation formats if rate-compatible punctured codewords are mapped onto sub-symbols with heterogeneous channel quality and modulation formats. In this paper, we demonstrate the application of our scheme to MIMO techniques. More specifically, we investigate non-orthogonal spatial multiplexing schemes in bit-interleaved coded OFDM systems. The techniques are evaluated within the context of the OFDMA/TDMA system designed within the EU FP6 Integrated Project WINNER.