基于混沌理论的SCCPM联合迭代解调译码算法

发布时间：2018-07-11 12:17

本文选题：连续相位调制 + 暂态混沌　；参考：《四川大学学报(工程科学版)》2014年03期

【摘要】：针对DVB-RCS2下行链路物理层中定义的串行级联连续相位调制信号迭代检测中存在的系统复杂度高、低信噪比条件下收敛性较差的问题,从匹配滤波器组和迭代译码两方面对系统进行改进,提出了一种基于混沌理论的联合迭代解调译码算法。该算法利用修正高斯小波函数的快速收敛特性来控制混沌迭代过程的动态区,并且结合延迟反馈控制法,有效抑制了迭代译码中暂态混沌对系统性能的影响,改善了系统在低信噪比条件下的收敛性,同时减少了迭代译码的次数。为了进一步解决计算迭代译码中的码字先验信息需要大量匹配滤波器的问题,通过计算协方差矩阵的条件数可得有效匹配滤波器具有很强相关性,提出的算法使用截断小特征值法来减弱这种相关性,从而对匹配滤波器组进行简化,在实际应用中仅使用4个匹配滤波器即可满足要求。仿真结果表明,提出的算法与传统算法相比,可以有效地降低系统复杂度,同时具有良好的迭代收敛性,并且适用于所有类型的CPM调制方案。
[Abstract]:Aiming at the problems of high system complexity and poor convergence under the condition of low signal-to-noise ratio (SNR), the iterative detection of serial cascade continuous phase modulation signals defined in the downlink physical layer of DVB-RCS2 is of high system complexity. A joint iterative demodulation decoding algorithm based on chaos theory is proposed by improving the system from two aspects: matched filter banks and iterative decoding. This algorithm utilizes the fast convergence of modified Gao Si wavelet function to control the dynamic region of chaotic iterative process, and combines with the delay feedback control method to effectively suppress the effect of transient chaos on the system performance in iterative decoding. The convergence of the system under low signal-to-noise ratio (SNR) is improved and the number of iterative decoding is reduced. In order to further solve the problem that a large number of matched filters are needed to calculate the prior information of codewords in iterative decoding, it is found that the effective matched filters have strong correlation by calculating the conditional numbers of covariance matrix. The proposed algorithm uses the truncated small eigenvalue method to reduce this correlation, thus simplifies the matched filter banks. In practical application, only four matched filters can meet the requirements. Simulation results show that the proposed algorithm can effectively reduce the complexity of the system compared with the traditional algorithm and has good iterative convergence and is suitable for all kinds of CPM modulation schemes.
【作者单位】：解放军信息工程大学信息系统工程学院;
【基金】：国家自然科学基金资助项目(61072046) 河南省自然科学基金资助项目(102300410008)
【分类号】：TN911.3

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