Reduced rank noncoherent interference suppression for CDMA communications

Noncoherent receivers are used for frequency-selective fading channels where the estimation of channel is difficult. The channel estimation can be more cumbersome for asynchronous code division multiple access (A-CDMA) systems due to multiaccess interference. A noncoherent reduced rank receiver which has less complexity as compared to noncoherent full rank linear minimum mean square error (MMSE) receiver is proposed for A-CDMA systems. The receiver for multipath channels consists of a reduced rank filter and a decision feedback differential detector (DF-DD) for each path. A generic bit error rate formula is provided for noncoherent reduced rank multistage decision feedback differential detection scheme.