Rapid iterative multiuser detection for UTRA-TDD in a time-variant multipath environment

Iterative multiuser detection has gained increasing attention, as a powerful method to mitigate the effects of multiple access interference (MAI) in CDMA systems. The polynomial expansion (PE) multiuser detector discussed in this paper can also be seen as an iterative approach to approximate the MMSE multiuser detector. It is shown that the PE detector can be applied such that it has fast convergence (few iterations) and high performance (comparable to the MMSE multiuser detector), while its computational complexity O(N²) remains well below that of most multiuser detectors. Simulation results for the third generation mobile communication system UTRA-TDD show the viability of the detector. Even in a time-variant multipath channel the PE detector can sustain its properties. The fast convergence of the PE detector is due to a very close estimation of the eigenvalues of the correlation matrix.