基于分段求解含错方程的扰码初态估计  

Estimation of initial state of scrambler based on piecewise solution of error equation

作　　者：谭继远 张立民 钟兆根 TAN Jiyuan;ZHANG Limin;ZHONG Zhaogen(School of Aviation Operations Service,Naval Aviation University,Yantai 264001,China;Navy Submarine Academy,Qingdao 266199,China;School of Aviation Basis,Naval Aviation University,Yantai 264001,China)

机构地区：[1]海军航空大学航空作战勤务学院,烟台264001 [2]海军潜艇学院,青岛266199 [3]海军航空大学航空基础学院,烟台264001

出　　处：《北京航空航天大学学报》2023年第11期3039-3046,共8页Journal of Beijing University of Aeronautics and Astronautics

基　　金：国家自然科学基金(91538201);泰山学者工程专项(ts201511020);信息系统安全技术重点实验室基金(6142111190404)。

摘　　要：针对低信噪比下扰码初态正确估计率低的问题,提出一种基于求解含错方程的扰码初态估计算法。根据初态递推关系,利用接收的软判决序列建立含错方程,将初态估计问题转化为含错方程组的求解;采用平均校验符合度来衡量含错方程组成立的可能性大小,通过遍历初态集合完成初态估计;通过分段寻优求解的方法来确定校验方程,该方法极大降低了高阶数下需要遍历的初态数。实验结果表明:所提算法在信噪比为0 dB的情况下,扰码初态正确估计率能达90%以上,相比于传统的卷积码快速相关攻击算法约有1~2 dB的性能提升。A method of initial state estimation of scrambling code based on solving the error equation is provided in order to address the issue of a low correct estimation rate of the initial state of scrambling code under a low signal-to-noise ratio.According to the initial state recurrence relation,the received soft decision sequence is used to establish the error-containing equation,and the initial state estimation problem is transformed into the solution of the error-containing equation system.The average check coincidence degree is proposed to measure the possibility of the establishment of the error-containing equation system,and the initial state estimation is completed by traversing the set of initial states.A piecewise solution equation method for finding the calibration equation is proposed,which greatly reduces the number of initial states that need to be traversed under high-order numbers.The experimental results show that the proposed algorithm can reach more than 90%of the correct estimation rate of the scrambled code initial state with a signal-to-noise ratio of 0 dB,which is about 1-2 dB performance improvement compared with the traditional fast correlation attack algorithm for convolutional codes.

关 键 词：同步扰码 初态估计 含错方程组 软判决 校验符合度 

分 类 号：V243.1[航空宇航科学与技术—飞行器设计] TN911.7[电子电信—通信与信息系统]