Ant colony optimisation-based multiuser detection for direct-sequence CDMA systems with diversity reception

An ant colony optimisation (ACO)-based multiuser detector assisted by spatial diversity reception using direct-sequence CDMA is proposed. By taking advantage of heuristic values and the collective intelligence of ACO, the proposed detector offers almost the same bit error rate (BER) performance as the full-search-based optimum multiuser detector does, while greatly reducing the computational complexity. The near-far resistance of the ACO-based multiuser detector is also examined. The BER performance for a ten-user system deteriorates scarcely when the interfering users´ energy is 12 dB higher than that of the desired user.