Fast joint detector and comparison with single user detection [WCDMA systems]

This paper derives and analyzes a novel FFT based joint detection algorithm. The paper compares the performance and complexity of the FFT based joint detector to that of the Cholesky based joint detector and single user detection algorithms. The algorithm can operate at chip rate sampling as well as higher sampling rates. For the performance/complexity analysis the TDD mode of WCDMA is considered. The results indicate that the performance of the fast FFT based joint detector is comparable to that of the Cholesky based joint detector and superior to that of single user detection algorithms. On the other hand, the complexity of the fast FFT based joint detector is significantly lower than that of the Cholesky based joint detector and comparable to that of the single user detection algorithms. For the Cholesky based joint detector, the approximate Cholesky decomposition is applied.