Title :
Directly estimated adaptive detectors for code-division multiple-access signals
Author :
Karayiannis, Nicolaos B. ; Chookiarti, Jackrit
Author_Institution :
Dept. of Electr. & Comput. Eng., Univ. of Houston, TX, USA
Abstract :
This paper presents adaptive multiuser detectors for code-division multiple-access (CDMA) signals in wireless communication systems. Directly estimated adaptive (DEA) detectors are developed by formulating CDMA detection as an inverse problem in the presence of channel-induced interference and noise. The detector parameters are computed by a fully sequential adaptive algorithm that requires no matrix inversion, and can be implemented online as the data arrive at the receiver. The proposed DEA detector is experimentally evaluated in terms of its robustness to noise, resistance to the near-far problem, and ability to handle multipath fading signals. This experimental study indicates that the proposed DEA detector requires shorter training sequences of bits to achieve the performance levels attained by existing adaptive implementations of the minimum mean-square error detector.
Keywords :
adaptive signal detection; code division multiple access; fading channels; least mean squares methods; multipath channels; multiuser detection; radiofrequency interference; recursive estimation; channel-induced interference; code-division multiple-access signal; directly estimated adaptive detector; minimum mean-square error detector; multipath fading signal; multiuser detection; recursive least-square method; sequential adaptive algorithm; wireless communication system; Adaptive algorithm; Adaptive signal detection; Adaptive systems; Detectors; Fading; Interference; Inverse problems; Multiaccess communication; Noise robustness; Wireless communication; Adaptive detector; code-division multiple access (CDMA); minimum mean-square error (MMSE); multiuser detection (MUD); near–far problem; recursive least-squares (RLS); wireless communications;
Journal_Title :
Communications, IEEE Transactions on
DOI :
10.1109/TCOMM.2004.842008