CPM receiver with immunity from carrier phase deviation

When perfect carrier estimation can not be obtained, which is a matter of frequent occurrence with a coherent demodulator, a receiver structure that is immune from or insensitive to the carrier deviation is preferable. Such a CPM receiver is proposed. The received signal, after being converted to baseband, is compared with a series of reference signals. By using the module constancy of the CPM signals, a decision criterion is derived. The reference message that matches the decision criterion best is selected to be the transmitted message. The receiver is completely immune from carrier phase deviation and is insensitive to frequency deviation. When a deviation of the carrier phase or frequency exists, the proposed receiver shows much better performance than the simplified coherent receiver. Simulation results that confirm the analysis are also given