Differential detection of correlative encoded continuous phase modulation schemes using decision feedback

The authors generalize a differential detection technique, which was introduced by A. Yongacoglu et al. (1988) for a Gaussian minimum shift-keying (GMSK) scheme, to include any correlative encoded continuous phase modulated (CECPM) signaling format. As in the previous work, the proposed symbol-by-symbol receivers use decision feedback to partially remove the effects of the destructive intersymbol interference (ISI), which corrupts the differentially detected CECPM signal. After achieving wider eyeopening with the decision feedback, the outputs of the two or more differential detectors are used together to further improve the performance. As a typical example of the CECPM family of signals, and because of its excellent spectral characteristics, the new receiver configurations using up to 3-b differential detectors have been applied to a tamed frequency modulation (TFM) signal. Bit-error rate performance evaluation results have indicated that performance improvements of more than 5 dB over the conventionally differential-detected TFM scheme are possible