Analysis of quasi-ML multiuser detection of DS/CDMA systems in asynchronous channels
Kwang Soon Kim, Iickho Song, Yun Hee Kim, Yong Up Lee, Jooshik Lee · IEEE Transactions on Communications · 1999
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.