A near-optimal multiuser detector for MC-CDMA systems using geometrical approach

An efficient sub-optimal algorithm, called HIS (hyperplane intersection and selection) detection algorithm, is proposed to solve the problem of joint detection of K users in an MC-CDMA system. Compared to existing solutions, the proposed algorithm has three characteristics very attractive for practical. systems. Firstly, it has nearly optimal performance. Secondly, it has a low computational complexity - O(K²) multiplications and O(K³) additions. Third, the algorithm has an inherent parallelism. To our knowledge, the HIS algorithm is not just an add-on to an existing algorithm, but rather a new decoding technique based on a singular value decomposition of the channel matrix, H. After giving the equation of the MC-CDMA multi-user detection problem, the HIS algorithm is described. Its performance is compared to known existing algorithms (ZF, MMSE, PIC and sphere decoding). For a BER as low as 10^-4, the HIS algorithm introduces only 0.2 dB degradation compared to the optimal sphere decoding algorithm for K=16 users against 3.8 dB for the PIC algorithm with two MMSE stages.