Title :
Iterative reduced-state multiuser detection for asynchronous coded CDMA
Author :
Qin, Zhiliang ; Teh, Kah Chan ; Gunawan, Erry
fDate :
12/1/2002 12:00:00 AM
Abstract :
The conventional maximum a posteriori receiver for coded code-division multiple-access (CDMA) systems has exponential computational complexity in terms of the number of users and the memory of the channel code. In this letter, we propose a low-complexity soft-input soft-output (SISO) multiuser detector based on the reduced-state a posteriori probability algorithm. Per-survivor processing and soft interference cancellation are used to remove the residual past and future interference in the branch metric computation. The complexity of the proposed receiver is related to the reduced memory of the CDMA channel and can be adjusted according to the complexity/performance tradeoff. Simulation results show that for asynchronous convolutionally coded systems, the proposed receiver can achieve the near-single-user performance for moderate to high signal-to-noise ratios.
Keywords :
code division multiple access; computational complexity; convolutional codes; interference suppression; iterative methods; multiuser detection; probability; radio receivers; radiofrequency interference; AWGN channel; CDMA channel; SISO multiuser detector; SNR; additive white Gaussian noise channel; asynchronous coded CDMA; asynchronous convolutionally coded systems; channel code memory; coded code-division multiple-access; complexity/performance tradeoff; exponential computational complexity; interference; iterative reduced-state multiuser detection; maximum a posteriori receiver; near-single-user performance; per-survivor processing; reduced-state a posteriori probability algorithm; signal-to-noise ratio; simulation results; soft interference cancellation; soft-input soft-output multiuser detector; Computational complexity; Computational modeling; Convolution; Convolutional codes; Detectors; Interference cancellation; Matched filters; Multiaccess communication; Multiuser detection; Signal to noise ratio;
Journal_Title :
Communications, IEEE Transactions on
DOI :
10.1109/TCOMM.2002.806526