| Summary: | 碩士 === 義守大學 === 電子工程學系 === 90 === In CDMA system, the complexity grown up with the user numbers increasing if we use the optimum receiver. The first part, we simulate several iterative multiuser detectors based on EM and relative algorithms. This simulation results show that in the same condition, MPEM detectors has the best performance, SAGE detector is normal , and EM detector has the worst. In convergence, SAGE detector is more fast, and than MPEM detector, EM detector converge after more stages. In complexity, MPEM detector has the most complexity with the more enduring of initial bits. Finally we simulate the effect of processing gain and initial bits.
The second part, we propose a new iterative EM HRD detector in multiuser multirate environments, and analyzes the detector performance in different conditions. We can observe the more iterations, the better performance. By another way, in the approximate complexity, te effect of the outside iterations is more than inside iterations. In the same number of users, the low rate users performance is better than high rate users; and in power control error simulation, we can increase the numbers of iteration, to decrease the effect of performance.
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