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提出一种采用频域处理和差分相位检测的M进制连续相位调制(CPM)接收机。这种CPM接收机是通过在频域上均衡相关的CPM相位信号恢复多电平M进制信息数据,而不是通过传统的最大似然序列估计(如Viterbi算法)在时域上对信号进行译码检测。为了采用频域处理或频域相位均衡,发射机和接收机分别采用循环前缀协助发射和差分相位检测。所提出这种结合差分相位检测和频域相位均衡的方法克服了使用基于分解的相关器和最大似然序列估计器的传统CPM接收机计算复杂度大的缺点,其相对于传统CPM接收机的性能损失则很小。以CPM解调参数(如调制指数和相位制约长度)来衡量,提出的接收机计算复杂度成对数增长,而Viterbi算法的复杂度是成指数增长。另外,差分相位检测器和频域相位均衡器取代了传统基于分解的CPM接收机中的一组相关器和滤波器。数学仿真结果表明提出的CPM接收机与采用基于分解的相关器的基于Viterbi算法的译码器的误比特性能接近。
A M-ary continuous phase modulation (CPM) receiver using frequency-domain processing and differential phase detection is proposed. This CPM receiver restores multilevel M-ary information data by equalizing the related CPM phase signals in the frequency domain, rather than translating the signal in the time domain by conventional maximum likelihood sequence estimation (eg, Viterbi algorithm) Code detection. In order to use frequency-domain processing or frequency-domain phase equalization, the transmitter and receiver respectively use a cyclic prefix to aid transmission and differential phase detection. The proposed method combining differential phase detection and frequency-domain phase equalization overcomes the drawback of the computational complexity of conventional CPM receivers using decomposition-based correlators and maximum likelihood sequence estimators, which overcomes the disadvantages of traditional CPM receivers Performance loss is small. In terms of CPM demodulation parameters (such as modulation index and phase constraint length), the proposed receiver computational complexity increases logarithmically, while the complexity of the Viterbi algorithm increases exponentially. In addition, the differential phase detector and frequency-domain phase equalizer replace the traditional decomposition-based CPM receiver in a group of correlators and filters. The mathematical simulation results show that the CPM receiver proposed has the similar bit error performance as the decoder based on the Viterbi algorithm based on the decomposition correlator.