After observing the correlative of pseudo noise code , we analyse the main cause of multi - access interference , and build the receiving model of multiuser system . in the thesis the optimum multiuser detectors with minimum probability of error and the near - optimum detectors are intrduced , and then pic multiuser detection is improved on 介紹了最佳多用戶檢測器和次最佳多用戶檢測器,并對現(xiàn)有一些并行干擾抵消多用戶檢測器進行了介紹并提出了改進的措施。對采用改進的算法的系統(tǒng)用montecarlo算法進行了誤碼性能分析。