Capacity Analysis for a Distributed MIMO-OFDM System in Composite Spatially Correlated Channels

Distributed antenna systems (DAS) have gained wide spread interest as an efficient means to expand system capacity, decrease transmission power and mitigate inter cell interference. In this paper, a distributed MIMO-OFDM system is studied over composite Rayleigh-lognormal multipath fading channels. Two kinds of information-theoretic capacity measures - ergodic capacity and outage capacity are evaluated. We also investigate the impact of spatial fading correlation on the capacity. From simulation results, we find that the distributed MIMO-OFDM scheme can bring a certain degree of capacity improvement because of macroscopic shadow fading diversity gain. Moreover, we show that, due to the decrease in spatial fading correlation, the distributed MIMO-OFDM scheme can provide capacity improvement compared with the conventional centralized MIMO-OFDM scheme.