Application of Wagner coding method to multi-DPSK system

A concrete example of the application of the Wagner coding method to the multi-DPSK system is presented. It is shown that the method can be applied to a parity check coding scheme which can be used in the DPSK channel accompanied by errors with memory, to a scheme for extracting channel measurement information in a multi-DPSK system, and to an error correcting scheme used following a differential decoder. Detailed theoretical analyses of bit error rate performance in the application of the proposed method to 4DPSK are made for the case when white Gaussian noise is assumed as a signal quality degradation factor and the case where phase jitter is contained in the recovered carrier. The effectiveness of the proposed method is confirmed in an experimental application to the 4DPSK system.