Title :
Turbo Multi-User Detection for OFDM/SDMA Systems Relying on Differential Evolution Aided Iterative Channel Estimation
Author :
Zhang, Jiankang ; Chen, Sheng ; Mu, Xiaomin ; Hanzo, Lajos
Author_Institution :
Sch. of Inf. Eng., Zhengzhou Univ., Zhengzhou, China
fDate :
6/1/2012 12:00:00 AM
Abstract :
A differential evolution (DE) algorithm aided iterative channel estimation and turbo multi-user detection (MUD) scheme is proposed for multi-user multi-input multiple-output aided orthogonal frequency-division multiplexing / space-division multiple-access (OFDM/SDMA) systems. The proposed scheme iteratively exchanges the estimated channel information and the detected data between the channel estimator and MUD employing a turbo technique, which gradually improves the accuracy of the channel estimation and the MUD, especially for the first iteration. Quadrature amplitude modulation (QAM) is employed in most wireless standards by virtue of providing a high throughput. However, the optimal maximum likelihood (ML)-MUD becomes extremely complex for employment in QAM-aided multi-user systems. Hence, two different DE aided MUD schemes, the DE aided minimum symbol error rate (MSER)-MUD as well as the discrete DE aided ML-MUD, were developed, and their achievable performance versus complexity was characterized. The simulation results demonstrate that the proposed DE aided channel estimator is capable of approaching the Cramer-Rao lower bound with just two or three iterations. The ultimate bit error rate lower-bound of the single-user additive white Gaussian noise scenario has been approached in the range of Eb / N0 ≥ 10 dB and Eb / N0 ≥ 6 dB for the DE aided MSER-MUD and the discrete DE aided ML-MUD, respectively.
Keywords :
MIMO communication; OFDM modulation; channel estimation; evolutionary computation; iterative methods; maximum likelihood estimation; multiuser detection; quadrature amplitude modulation; space division multiple access; Cramer-Rao lower bound; OFDM system; QAM; SDMA system; additive white Gaussian noise; differential evolution aided iterative channel estimation; multiuser multi-input multiple-output system; optimal maximum likelihood multiuser detection; orthogonal frequency division multiplexing system; quadrature amplitude modulation; space division multiple access system; turbo multiuser detection; Channel estimation; Modulation; Multiaccess communication; Multiuser detection; OFDM; Optimization; Vectors; Orthogonal frequency division multiplexing (OFDM); differential evolution (DE) algorithm; minimum symbol error rate (MSER); multiuser detection (MUD); space-division multiple-access (SDMA);
Journal_Title :
Communications, IEEE Transactions on
DOI :
10.1109/TCOMM.2012.032312.110400