To satisfy energy and complexity constraints, embedded wireless systems require fixed-point arithmetic implementation. To optimize the fixed-point specification, existing approaches are based on fixed-point simulations to evaluate the performances. In this paper, the approach used to optimize the fixed-point specification for a WCDMA receiver is presented. The dynamic range and the fixed-point accuracy are evaluated analytically in our approach. The analytical accuracy constraint expression according to the bit error rate (BER) is proposed. The results show that the optimized ixed point specification depends on the input receiver signal-to-noise ratio (SNR).