Space-frequency filtering for multicarrier CDMA systems

In this paper, we consider blind signal detection in a multicarrier direct-sequence code-division multiple- access system using an antenna array. A space-frequency filtering approach is proposed to coherently combine the desired signal contribution from all the space-frequency branches. Under the assumption of ideal knowledge of the channel and direction of arrival parameters, it is shown that the proposed space-frequency matched filtering approach provides the same performance as that of beamforming with maximum ratio combining. When blind detection is considered, however, the proposed approach exhibits superior performance to the latter. Numerical results are presented to demonstrate the effectiveness of the proposed blind detection approach.