Detection and channel estimation algorithms for chip-level space-frequency block coded MC-CDMA systems

A combined space-frequency (SF) block coding and multi-carrier code division multiple access (MC-CDMA) scheme for downlink transmissions is presented, in which SF block coding is performed at the chip level, i.e. after code spreading. For this scheme, we develop linear single-user joint SF decoding and detection algorithms that exhibit low complexity, low decoding delay and enhanced performance for frequency-selective fading channels compared to their symbol-level counterparts. In addition, it is demonstrated that by exploiting the signal structure imposed by the chip-level SF block coding, blind channel estimation (with only a scalar ambiguity) is feasible, without assigning multiple signatures to each user. Finally, simulation examples demonstrate the performance of the proposed algorithms.