OFDMA Capacity Analysis in MIMO Channels

In this paper, the performance of orthogonal frequency division multiple access orthogonal frequency division multiple access (OFDMA) is studied in the context of the general multiuser multicarrier multiple-input multiple-output (MIMO) (M 3 ) system for both uplink (UP) and downlink (DL) channels. The relationship between OFDMA and the optimal M 3 solution is investigated from an information theoretical point of view. Specifically, the necessary and sufficient conditions of OFDMA being the capacity-maximizing M 3 transmission scheme is derived. In addition, OFDMA optimality is explicitly analyzed in some special cases.