Performance evaluation of differential GMSK using k-th order detectors

The relationship between k consecutive outputs of the conventional differential detector and the output of a differential detector with a k-bit delayer for a minimum shift keying (MSK) and Gaussian-filtered MSK (GMSK) system is investigated. It is shown that the output of the k-th order detector for the MSK and GMSK signal, using a k-bit delay circuit, is the product of k successive outputs of the conventional differential detector. This relationship is used to achieve performance gains over conventional differential detection. The error rate performance of the proposed method is carried out by computer simulation, and performance improvement is achieved for differential MSK and GMSK systems.