多调制指数CPM信号的新分解方式及其准相干解调

针对卫星通信等资源受限的无线通信系统,研究了多调制指数连续相位调制(Multi-h continuous phase modulation, Multi-h CPM)信号的调制与解调相关问题。首先提出了一种新的分解方式来简化Multi-h CPM信号的调制过程,并给出了相应的周期性状态网格图。然后根据新的分解方式设计了一种适用于Multi-h CPM信号的导频辅助准相干解调算法,并从功率谱和误码性能两方面对所设计的Multi-h CPM信号和单调制指数CPM(Single-h CPM)信号进行了评估与比较。仿真结果表明:无论采用何种频率脉冲, Multi-h CPM信号都要比Single-h CPM信号具有更加光滑的功率谱曲线;仅两个导频符号辅助下,未编码Multi-h CPM系统较未编码Single-h CPM系统有将近2 dB的性能增益,且在低信噪比下,编码Multi-h CPM系统性能要比编码Single-h CPM系统好0.1~0.25 dB。

Decomposition and quasi-coherent demodulation of Multi-h CPM signal

Considering resource-limited wireless communications such as satellite communications, the relevant problems of modulation and demodulation of multi-h continuous phase modulation (multi-h CPM) signals are studied. A new way of decomposition is first designed to simplify the modulation process of the multi-h CPM signals, followed by a periodic state trellis. Then, a pilot-aided quasi-coherent demodulation algorithm is proposed to detect the multi-h CPM signals according to the designed decomposition. Moreover, the multi-h CPM signals and the single-h CPM signals are evaluated and compared from the two aspects of power spectrum and bit error performance. Simulation results show that, no matter what frequency pulse is used, the multi-h CPM signals have smoother power spectrum curves than the single-h CPM signals; only with the assistance of two pilot symbols, the performance gain of the uncoded multi-h CPM system is nearly 2 dB compared with that of the uncoded single-h CPM system, and the coded multi-h CPM system can achieve performance gain of 0.1 dB to 0.25 dB more than the coded single-h CPM system at low signal-to-noise ratios (SNRs).