非对称成对载波多址信号的相位误差分析及幅度改进算法

针对由主站和小站信号同频混合而成的非对称成对载波多址（PCMA）信号解调问题，构建了一种实现此类信号解调的框架。参数估计是非对称PCMA通信系统在实现两路信号分离解调时不可或缺的环节，对于幅度参数估计精度问题，提出一种基于四次方法的搜索式幅度估计算法。首先建立非对称PCMA系统解调模型并作出基本假设，然后对不同假设下的相位误差进行对比并分析相位误差对幅度估计算法的影响，最后提出一种新的幅度估计算法。实验结果表明在相同信噪比（SNR）下，正态相位误差下的小站信号解调性能要劣于其均值条件下的解调性能。当误比特率（BER）在数量级为10^-4时，改进算法下小站信号的解调性能提升了1 dB，说明改进算法优于四次方法。

Phase error analysis and amplitude improvement algorithm for asymmetric paired carry multiple access signal

To solve the signal demodulation problem of asymmetric Paired Carry Multiple Access (PCMA) composed of the same frequency of main station and small station signals, a framework to realize this kind of signal demodulation was constructed. Parameter estimation is an indispensable part in the realization of two-way signal separation and demodulation for asymmetric PCMA communication systems. For the estimation accuracy of amplitude parameters, a searching amplitude estimation algorithm based on fourth-power method was proposed. Firstly, the demodulation model for asymmetric PCMA systems was established and the basic assumptions were made. Then the phase errors under different assumptions were compared with each other and the influence of phase error on the amplitude estimation algorithm was analyzed. Finally, a new amplitude estimation algorithm was proposed. Experimental results show that, under same Signal-to-Noise Ratio (SNR), the demodulation performance of the small station signal under normal phase error is inferior to its demodulation performance under mean value condition. When the order of magnitude of the Bit Error Rate (BER) is 10^-4, the demodulation performance of small station signal is improved by 1 dB with the improved algorithm, proving that the improved algorithm is better than fourth-power method.