A Novel Two-Stage CMA-Based Blind Receiver With Adaptive Stepsize

In the direct sequence code division multiple access (DS-CDMA) system with high data rate over frequency-selective channel, the two-stage blind receiver based on constant modulus algorithm (CMA) can implement joint equalization and multiuser detection in DS-CDMA system over frequency-selective channel, while the real-time performance capability of it has been proved to be well. In the two-stage CMA adaptive blind receiver, however, the adaptive algorithm of the first stage’s detector is based on Recursive Least Square (RLS) algorithm, and this algorithm has some shortcomings in robustness of convergence and so on, that will lead to the performance degradation of the whole adaptive blind receiver. In this paper, we substitute Recursive Least Square algorithm by Dai-Yuan (DY) adaptive stepsize algorithm in the first stage’s detector, and we also give the whole implementation scheme for our proposed algorithm. The theoretical analysis and computer simulation both show that our proposed algorithm outperforms the original algorithm, it has much lower bit error rate (BER) and much higher signal to interference plus noise ratio (SINR).