Noncoherent detection of hardlimited O-QPSK

The authors present a detection technique that is suitable for a mobile communication system using a hardlimited 100% root-raised cosine O-QPSK signal. A noncoherent detection algorithm is presented with an example. The algorithm takes advantage of the mid-bit samples of the received signal by correlating them with a set of hypotheses. The best hypothesis is chosen and the mid-bit estimates are differentially detected in the inphase and quadrature separately to yield the transmitted bits. Simulation results are shown to illustrate the performance of the technique for channels typical of the mobile communication scenarios. The performances are shown to be as good as π/4-QPSK with multiple symbol differential detection. The performances are compared with π/4-QPSK for a typical single channel per carrier system with adjacent channel interference. The O-QPSK scheme is shown to be significantly better than π/4-QPSK for all practical scenarios