Subspace-based blind multiuser detection for quasi-synchronous MC CDMA systems

A subspace-based linear minimum mean-square error (MMSE) multiuser detector is proposed for quasi-synchronous multicarrier code-division multiple-access (MC-CDMA) systems. The proposed receiver is totally blind, i.e., it is both channel- and delay-independent and, unlike many subspace-based algorithms, requires only an upper bound (rather than the exact knowledge) of the channel order, without needing explicit delay estimation. The effectiveness of the proposed blind approach is tested by computer simulation results, which show that it assures satisfactory performances in severe near-far scenarios, while exhibiting a lower computational complexity in comparison with existing subspace-based methods.