Title :
Analysis of quasi-ML multiuser detection of DS/CDMA systems in asynchronous channels
Author :
Kim, Kwang Soon ; Song, Iickho ; Kim, Yun Hee ; Lee, Yong Up ; Lee, Jooshik
Author_Institution :
Dept. of Electr. & Comput. Eng., California Univ., San Diego, La Jolla, CA, USA
fDate :
12/1/1999 12:00:00 AM
Abstract :
We consider the quasi-maximum-likelihood (quasi-ML) detectors of the reverse link system that uses antenna arrays in asynchronous channels when the channel vector is time-invariant and time-varying. A channel vector estimation method based on eigendecomposition for time-invariant channels and its adaptive version suitable for the time-varying channels are also proposed. It is shown that the proposed quasi-ML detector can be regarded as a beamformer followed by a decorrelating filter and that the proposed system performs better than the conventional decorrelator scheme. It is also observed that the performance gain of the proposed scheme over the conventional decorrelator system increases as the numbers of active users and antenna arrays increase
Keywords :
adaptive antenna arrays; adaptive estimation; array signal processing; code division multiple access; decorrelation; eigenvalues and eigenfunctions; filtering theory; matrix decomposition; maximum likelihood detection; multiuser channels; radio links; recursive estimation; spread spectrum communication; time-varying channels; DS/CDMA systems; adaptive estimation; antenna arrays; asynchronous channels; beamformer; channel vector estimation method; correlation matrix; decorrelating filter; decorrelator system; eigendecomposition; fast recursive algorithm; mobile radio; performance gain; quasi-ML multiuser detection; quasi-maximum-likelihood detectors; reverse link system; time-invariant channel vector; time-invariant channels; time-varying channel vector; time-varying channels; Antenna arrays; Decorrelation; Detectors; Filters; Multiaccess communication; Multiuser detection; Performance gain; Sensor arrays; Time varying systems; Time-varying channels;
Journal_Title :
Communications, IEEE Transactions on
