Performance analyses of adaptive noncoherent receivers for MC‐CDMA communications

Abstract

SUMMARYIn this paper, we propose differential phase-shift keying (DPSK) noncoherent receivers for multicarrier code division multiple access systems in multipath channels. The noncoherent receivers are composed of a linear equalizer and a decision-feedback differential detector to detect DPSK signals. The performances of the proposed noncoherent receivers can be improved by increasing the number of feedback symbols. For an infinite number of feedback symbols, the optimum weight can be derived analytically, and the performances of the proposed noncoherent receivers approach that of the conventional coherent receiver. For adaptation of the equalizer coefficients, modified least mean square and recursive least squares algorithms are proposed. Furthermore, the reduced-rank schemes are proposed to simplify the system complexities. Some simulation examples are given to show the system performances of the four proposed receivers.