DS-CDMA receiver with sigma-delta modulation encoding

In this paper, a new direct-sequence code-division-multiple-access (DS-CDMA) receiver with very simple architecture is proposed. The new design is based on sigma-delta (ΣΔ) modulation encoding and hence it is named as ΣΔ-CDMA receiver. Unlike the conventional receiver, the ΣΔ-CDMA receiver does not have a ΣΔ demodulator and a root-raised-cosine (RRC) filter, and its despreader is simply XNOR gates. The bit-error-rate performance is analyzed and simulated. It is shown that the predicted performance agrees closely with the simulated one at sufficiently high over-sampling-ratio or in the presence of multiple users. The performance difference between the proposed and conventional CDMA receiver is also very small under the same conditions.