Hybrid Iterative Multiuser Detection for Channel Coded Space Division Multiple Access OFDM Systems

Abstract

Abstract-Space division multiple access (SDMA) aided orthogonal frequency division multiplexing (OFDM) systems assisted by efficient multiuser detection (MUD) techniques have recently attracted intensive research interests. The maximum likelihood detection (MLD) arrangement was found to attain the best performance, although this was achieved at the cost of a computational complexity, which increases exponentially both with the number of users and with the number of bits per symbol transmitted by higher order modulation schemes. By contrast, the minimum mean-square error (MMSE) SDMA-MUD exhibits a lower complexity at the cost of a performance loss. Forward error correction (FEC) schemes such as, for example, turbo trellis coded modulation (TTCM), may be efficiently combined with SDMA-OFDM systems for the sake of improving the achievable performance. Genetic algorithm (GA) based multiuser detection techniques have been shown to provide a good performance in MUD-aided code division multiple access (CDMA) systems. In this contribution, a GA-aided MMSE MUD is proposed for employment in a TTCMassisted SDMA-OFDM system, which is capable of achieving a similar performance to that attained by its optimum MLD-aided counterpart at a significantly lower complexity, especially at high user loads. Moreover, when the proposed biased Q-function based mutation (BQM) assisted iterative GA (IGA) MUD is employed, the GA-aided system's performance can be further improved, for example, by reducing the bit error ratio (BER) measured at 3 dB by about five orders of magnitude in comparison to the TTCMassisted MMSE-SDMA-OFDM benchmarker system, while still maintaining modest complexity.Index Terms-Biased Q-function based mutation (BQM), genetic algorithm (GA), minimum mean-square error (MMSE), multiuser detection (MUD), orthogonal frequency division multiplexing (OFDM), space division multiple access (SDMA), turbo trellis coded modulation (TTCM).

Multiuser MIMO-OFDM for Next-Generation Wireless Systems

“…In order to further improve the achievable performance of MIMO SDMA-OFDM systems, the enhanced GA-based MUDs of [281], [282] can be employed, which improve the detector's performance by each or both of the following two aspects.…”

Interference - mitigating waveform design for next-generation wireless systems

“…The novel IGA-aided technique employed the novel Biased Q-function Based Mutation (BQM) technique proposed in [15] for the sake of approaching the performance of the ML detector at the cost of a substantially lower complexity. Observe in the figure that both perfect and imperfect channel estimation scenarios were considered and that the number of users was L= 6 -8, while the number of SDMA receiver antenna elements was P=6.…”

A High Throughput Configurable SDR Detector for Multi-user MIMO Wireless Systems

“…However, direct implementation of ML grows exponentially with the number of antennas and the modulation scheme, making its ASIC or FPGA implementation infeasible for all but low-density modulation schemes using a small number of antennas. Sphere detection [1], and its K-best variation, has been proposed [2], analyzed [3] and implemented [4][5][6][7][8][9].…”