MIMO-OFDM Transmission Adaptation using Rank

In this paper, adaptive transmission using channel rank for MIMO-OFDM system is considered. Different transmission schemes have different diversity and multiplexing tradeoff characters. Adjusting MIMO transmission scheme according to channel quality indicator (CQI) or channel state information will improve system performance. We propose a new transmission adaptation solution depending on two-dimensional channel quality indicators with the aim to enhance system throughput performance. This is realized by using different space-time modulation schemes, which support different data streams. The proposed scheme is verified by simulation with practical radio propagation models, where different correlation scenarios are considered. In contrast to fixed transmission mode and only SNR based adaptive method, the proposed two dimensional CQI solution has more throughput gain with limited feedback.