DocumentCode :
1273625
Title :
Turbo multiuser detection with unknown interferers
Author :
Reynolds, Daryl ; Wang, Xiaodong
Author_Institution :
Dept. of Electr. Eng., Texas A&M Univ., College Station, TX, USA
Volume :
50
Issue :
4
fYear :
2002
fDate :
4/1/2002 12:00:00 AM
Firstpage :
616
Lastpage :
622
Abstract :
We consider the problem of turbo multiuser detection for synchronous and asynchronous code-division multiple-access (CDMA) in the presence of unknown users. Turbo multiuser detectors, as previously developed, typically require knowledge of the signature waveforms of all of the users in the system and ignore users whose signature sequences are unknown, e.g., users outside the cell. We develop turbo multiuser detection for CDMA uplink systems and other environments in which the receiver has knowledge of the signature waveforms of only K˘⩽ K users. Subspace techniques are used to estimate the interference from the unknown-users and the interference estimate is subtracted from the received signal. We see that the new receiver significantly outperforms the conventional turbo multiuser receiver for moderate and high signal-to-noise ratios. It is also seen that the traditional turbo receiver provides little gain through iteration when unknown users are present
Keywords :
code division multiple access; interference suppression; multiuser channels; radio links; radio receivers; radiofrequency interference; signal detection; turbo codes; CDMA uplink systems; MMSE group-blind multiuser detector; SNR; asynchronous CDMA; code-division multiple-access; interference suppression; interferers; signal-to-noise ratio; signature sequences; signature waveforms; simulation results; subspace techniques; synchronous CDMA; turbo codes; turbo multiuser detection; turbo receiver; Convolutional codes; Detectors; Filtering; Interference cancellation; Intersymbol interference; Iterative decoding; Multiaccess communication; Multiuser detection; Signal to noise ratio; Turbo codes;
fLanguage :
English
Journal_Title :
Communications, IEEE Transactions on
Publisher :
ieee
ISSN :
0090-6778
Type :
jour
DOI :
10.1109/26.996076
Filename :
996076
Link To Document :
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