MIMO-OFDM outage channel capacity with practical imperfect CSI

Link adaptation is one of the key features of modern 3G and 4G communication systems, enabling a significant boost in achievable throughput. Accurate link error prediction (related to channel capacity estimation) is required for implementation of link adaptation. Practical link adaptation algorithms almost universally require extensive simulation effort. On the other hand, research based on information theory, while considering non-ideal Channel State Information (CSI), has been limited to MMSE estimation algorithms, which are frequently not used in practice. In this paper we attempt to bridge the gap between these two approaches by extending the MIMO-OFDM outage capacity lower bound to practical Channel Estimation (CE) algorithms, such as Least Squares (LS) estimation combined with linear interpolation, and RF imperfections such as frequency offset. Numerical results show the significant impact of practical CE methods on outage capacity in both low and high SNR region. Conversely, frequency offset is shown to have relatively small impact at low SNR, while limiting outage capacity at high SNR.