Multiuser detection of asynchronous CDMA with frequency offset

This letter presents a near–far resistant detection scheme for asynchronous code-division multiple access with frequency offset. Based on a one-shot technique and Taylor expansion, a zeroth-order and a first-order one-shot linear decorreating detector (LDD) are proposed. The zeroth-order LDD has simple architecture but suffers performance degradation for large frequency offset. The first-order one-shot LDD, with increased complexity, has very good near–far resistant property even for large frequency offset. Two versions of the first-order one-shot LDD are investigated according to different Taylor expansion approaches. The feasibility of the proposed detectors is demonstrated by computer simulations.