Adaptive parallel interference cancellation receiver in CDMA satellite system

摘要

Future satellite communication systems will be characterized by broadband, multimedia services, and large capacity of mobile terminals. Low Earth Orbit (LEO) system with multiple spot-beams per satellite using Code Division Multiple Access (CDMA) is a good choice. In this paper, an adaptive parallel interference cancellation detector is proposed for reverse link with both intra-beam and inter-beam multiple access interference (MAI). The proposed linear adaptive receiver achieves essential advantages with respect to MAI with a little more complex than the conventional matched-filter receiver. The receiver structure is all feed-forward and more stable than many other multiuser detectors. We then study several adaptive algorithms with the aid of training sequence, and compare them with blind algorithm in order to find the good tradeoff among the performance, complexity and bandwidth-extension. With only small modification, the receiver can work well in multirate cases which are usually hopeful in multimedia services. With the test of simulations under AWGN and time-varying Ricia'n channels, the proposed receiver can reach good performance with considerable increasing user capacity.