Finite word length effects on the performance of MMSE receiver for DS-CDMA systems

The minimum mean square error (MMSE) receiver for a DS-CDMA system is capable of suppressing multiple access interference (MAI), unlike the conventional digital matched filter (DMF) receiver. Moreover, this type of receiver offers implementation advantages over optimum receivers for DS-CDMA systems. However, the performance of the MMSE receiver is affected by the quantization of the adaptive filter coefficients and the analog-to-digital converter (ADC) output. In this paper, the performance degradation of the MMSE receiver due to finite precision arithmetic of a digital signal processor is simulated for both non-fading and fading channels. The performance comparison between the MMSE receiver and the DMF receiver, for a given number of bits per sample, is also evaluated