Dynamic channel mapping strategies in adaptive MIMO systems

A channel mapping strategies and their impact on bit error rate (BER) and on system capacity for multiple-input multiple-output MIMO systems in a quasistatic flat fading channel is analysed. MIMO orthogonal subchannels are split into reliable subchannels, where the target BER can be guaranteed, and unreliable subchannels, where the requirements of target BER cannot be met. The modulation level of M-QAM signal transmitted in a reliable subchannel is dynamically adapted to channel state information. The information is transmitted only in reliable subchannels in the elementary channel mapping strategy, while in advanced channel mapping strategies, one, two or more subchannels are combined to increase the system capacity. The average channel capacity achieved by an elementary mapping strategy does not differ significantly from that for advanced ones for high SNR (signal to noise ratio), while at low and medium SNR only the advanced channel mapping strategies guarantee the target BER in the communication link.