Phase differential block demodulation of hardlimited MSK signals

We investigate a block detection strategy for hard limited MSK signals. In contrast to the published work of Leib and Pasupathy (see EEE-TC, vol.40, p.1430-1441, September 1992) on optimal incoherent block detection, only first order phase differentials are exploited. This reduces the implementation complexity of a block detector significantly, since no complex valued calculations are necessary. A near-maximum likelihood detection metric is derived by suitably approximating the joint probability density function of a block of phase differentials. It is shown that the proposed detection scheme approaches the performance of coherent detection with increasing block lengths. Compared to coherent antipodal signalling, a degradation in performance still remains which is determined by the predetection filter