DocumentCode :
1343172
Title :
Blind multiuser detection: a subspace approach
Author :
Wang, Xiaodong ; Poor, H. Vincent
Author_Institution :
Dept. of Electr. Eng., Princeton Univ., NJ, USA
Volume :
44
Issue :
2
fYear :
1998
fDate :
3/1/1998 12:00:00 AM
Firstpage :
677
Lastpage :
690
Abstract :
A new multiuser detection scheme based on signal subspace estimation is proposed. It is shown that under this scheme, both the decorrelating detector and the linear minimum-mean-square-error (MMSE) detector can be obtained blindly, i.e., they can be estimated from the received signal with the prior knowledge of only the signature waveform and timing of the user of interest. The consistency and asymptotic variance of the estimates of the two linear detectors are examined. A blind adaptive implementation based on a signal subspace tracking algorithm is also developed. It is seen that compared with the previous minimum-output-energy blind adaptive multiuser detector, the proposed subspace-based blind adaptive detector offers lower computational complexity, better performance, and robustness against signature waveform mismatch. Two extensions are made within the framework of signal subspace estimation. First, a blind adaptive method is developed for estimating the effective user signature waveform in the multipath channel. Secondly, a multiuser detection scheme using spatial diversity in the form of an antenna array is considered. A blind adaptive technique for estimating the array response for diversity combining is proposed. It is seen that under the proposed subspace approach, blind adaptive channel estimation and blind adaptive array response estimation can be integrated with blind adaptive multiuser detection, with little attendant increase in complexity
Keywords :
adaptive estimation; adaptive signal detection; adaptive signal processing; array signal processing; code division multiple access; computational complexity; correlation methods; direction-of-arrival estimation; diversity reception; least mean squares methods; multipath channels; spread spectrum communication; tracking; DS-CDMA; MMSE detector; antenna array; asymptotic variance; blind adaptive array response estimation; blind adaptive channel estimation; blind adaptive multiuser detector; blind multiuser detection; computational complexity; decorrelating detector; diversity combining; linear detectors; linear minimum-mean-square-error; minimum-output-energy; multipath channel; signal subspace estimation; signal subspace tracking algorithm; signature waveform mismatch; spatial diversity; subspace-based blind adaptive detector; Adaptive arrays; Antenna arrays; Computational complexity; Decorrelation; Detectors; Diversity reception; Multipath channels; Multiuser detection; Robustness; Timing;
fLanguage :
English
Journal_Title :
Information Theory, IEEE Transactions on
Publisher :
ieee
ISSN :
0018-9448
Type :
jour
DOI :
10.1109/18.661512
Filename :
661512
Link To Document :
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