基于Rimoldi分解的连续相位调制信号Turbo频域均衡算法

摘要

To solve the issues of the high complexity and poor performance in the equalization of high order and partial response Continuous Phase Modulation (CPM) signals, a new framework of tilted phase CPM transmitted signals is designed from the perspective of Rimoldi decomposition. A novel frequency domain equalization algorithm for high order CPM signals is proposed based on the combination of single-carrier Frequency Domain Equalization (FDE) and Turbo equalization. This algorithm avoids the large matrix inversions in computation of the equalizer coefficients in time domain by transforming the signal equalization to frequency domain. Simultaneously, it improves the system performance by soft information iterative process. The analysis and simulation results show that in multipath fading channels with serious inter-symbol interference the proposed algorithm provides a relatively lower computational complexity and a performance gain of about 1.5 dB in signal-noise ratio compared with the previously proposed FDE algorithm based on symbol for fourth-order and partial response CPM signals.%针对高阶部分响应连续相位调制(CPM)信号均衡中存在的复杂度高和性能较差等问题，该文从 Rimoldi分解的角度出发，设计了一种新的适用于倾斜相位 CPM 信号的发射帧结构，并在此基础上结合单载波频域均衡(FDE)和Turbo均衡的思想，提出了一种适用于高阶CPM信号的Turbo频域均衡算法。该算法通过将信号均衡转化到频域进行处理，避免了时域均衡算法在计算均衡器系数时存在的大矩阵求逆问题，同时使用 Turbo 均衡的软信息迭代处理来改善系统的性能。理论分析和仿真结果表明，对于四阶部分响应CPM信号，在存在严重符号间干扰的多径衰落信道的条件下，该算法与现有的基于符号的频域均衡算法相比，在保持较低复杂度的同时，具有大约1.5 dB的性能增益。