Multi-branch Fractional Multi-bit Differential Detection for GMSK Signals

The multi-branch fractional multi-bit differential detection for improving the performance of Gaussian minimum shift keying (GMSK) is studied. The essential of the technique is explained from its physical point of view, and the upper bound of the fractional bit duration for the maximum performance improvement is given. The computer simulation and analysis results show that the multi-branch fractional multi-bit differential detection technique increases the distance between phase states compared with one-bit differential detection; when the fractional bit duration is the maximal duration in which the symbol decision is not influenced, the maximum performance gain can be obtained.