Title :
A new approach to greedy multiuser detection
Author :
AlRustamani, Amina ; Vojcic, Branimir R.
Author_Institution :
Dubai Internet City, United Arab Emirates
fDate :
8/1/2002 12:00:00 AM
Abstract :
We propose a new suboptimum multiuser detector for synchronous and asynchronous multiuser communications. In this approach, a greedy strategy is used to maximize the cost function, the maximum-likelihood (ML) metric. The coefficients of the ML metric are utilized as weights indicating in which order bits can be estimated. The complexity of the algorithm is approximately K2 log K per bit, where K is the number of users. We analyze the performance of the greedy multiuser detection in the additive white Gaussian noise channel as well as in the frequency-nonselective Rayleigh fading channel, and compare it with the optimum detector and several suboptimum schemes such as conventional, successive interference cancellation, decorrelator, sequential, and multistage detectors. The proposed greedy approach considerably outperforms these suboptimum schemes, especially for moderate and high loads in low and moderate signal-to-noise ratio regions. The results show that when there is a significant imbalance in the values of the coefficients of the ML metric due to moderate to high noise, fading, and asynchronous transmission, near-optimum performance is achieved by the greedy detection.
Keywords :
AWGN channels; Rayleigh channels; code division multiple access; interference suppression; maximum likelihood detection; multiuser channels; radiofrequency interference; AWGN channel; CDMA; ML metric coefficients; SNR; additive white Gaussian noise channel; asynchronous multiuser communications; asynchronous transmission; code-division multiaccess; cost function maximisation; decorrelator; frequency-nonselective Rayleigh fading channel; greedy multiuser detection; maximum-likelihood metric; multistage detector; near-optimum performance; optimum detector; performance analysis; sequential detector; signal-to-noise rati; suboptimum multiuser detector; successive interference cancellation; synchronous multiuser communications; Additive white noise; Cost function; Detectors; Fading; Frequency; Interference cancellation; Maximum likelihood detection; Maximum likelihood estimation; Multiuser detection; Performance analysis;
Journal_Title :
Communications, IEEE Transactions on
DOI :
10.1109/TCOMM.2002.801493