A variable step-size EASI algorithm based on PI for DS-CDMA system blind estimation

To solve the problem of the direct sequence code division multiple access (DS-CDMA) system multiuser detection, this paper proposes a variable step-size based on performance index (PI) EASI algorithm for information code and chip sequence blind estimation. Contrasting blind source separation (BSS) and DS-CDMA system model, the algorithm uses adaptive method to estimate the mixing matrix for estimating the chip sequence, and uses the demixing matrix to separate the observation signal for estimating the information code. In addition, the algorithm uses evaluation performance index (PI) to adjust the step-size, this makes the convergence speed and stability of the algorithm reach an ideal balance. The experimental results show that the algorithm has good resistance to multi-access interference (MAI). The bit error rate (BER) of information code is below 10⁻² in 0 dB.