Performance evaluation of adaptive MIMO-OFDM systems with imperfect feedback in measurement based channels

This paper presents a performance evaluation of enhanced link adaptation techniques for MIMO-OFDM systems with imperfect feedback and channel estimation. In the link-level simulations, the channel modeling is based on MIMO channel measurements in line-of-sight and non line-of-sight scenarios. An adaptation process that switches between beamforming, diversity and multiplexing modes in combination with various modulation schemes is based on the effective SINR. Mutual information effective SINR mapping method is used as a part of the spatial and modulation scheme selection process due to its capability for estimating the error rate performance of large variety of MIMO channels accurately. Simulation results show that a simple adaptive system which applies diversity and multiplexing modes attains good performance in realistic 2 times 2 MIMO channels. It is also shown that the imperfect feedback and channel estimation can have a significant impact on the system performance.