子载波信道模型盲均衡非合作水声正交频分复用类内调制识别  

Non-cooperative underwater acoustic OFDM intra-class modulation recognition based on subcarrier channel model blind equalization

作　　者：方涛 华波 韦佳利 王凯 刘今 王彪[1] FANG Tao;HUA Bo;WEI Jiali;WANG Kai;LIU Jin;WANG Biao(Ocean College,Jiangsu University of Science and Technology,Zhenjiang 212008;Systems Engineering Research Institute,CSSC,Beijing 100094)

机构地区：[1]江苏科技大学海洋学院,镇江212008 [2]中国船舶集团有限公司系统工程研究院,北京100094

出　　处：《声学学报》2024年第5期1061-1072,共12页Acta Acustica

基　　金：江苏科技大学科研启动基金项目(1202932204);江苏省高等学校基础科学(自然科学)研究项目(23KJB510003)资助。

摘　　要：针对水声多径信道下传统正交频分复用(OFDM)类内调制识别特征稳健性不足导致识别方法失效的问题,提出了基于子载波信道模型盲均衡的水声OFDM类内调制识别方法,可识别类内调制方式包括BPSK、QPSK、8PSK及16QAM。首先,提出一种针对OFDM子载波映射符号的分块策略提高盲均衡的性能。然后,利用期望最大化(EM)算法,在该分块策略下对每个分块内的子载波映射符号进行处理,估计出信道衰落系数和噪声功率;进一步利用K均值聚类(K-means)算法得到该分块映射符号对应的信道衰落系数,并将该信道衰落系数作为EM算法的初始值,使EM算法能够快速收敛。最后,利用最大似然(ML)分类器实现OFDM类内调制识别。仿真和实验结果表明,提出的EM-Block-ML方法实现了水声多径信道下高可靠的OFDM类内调制识别,验证了所提识别方法的有效性。In order to address the problem of insufficient robustness in the traditional orthogonal frequency division multiplexing(OFDM)intra-class modulation recognition features within underwater acoustic multipath channel,which has resulted in recognition method failures,this paper studies the intra-class modulation recognition method of underwater acoustic OFDM based on blind equalization of subcarrier channel model,including BPSK,QPSK,8PSK and 16QAM modulations.Firstly,the block strategy for OFDM subcarrier mapping symbols is proposed based on the channel characteristics.Then,the expectation maximization(EM)algorithm is employed to process the subcarrier mapping symbols within each block to estimate the channel fading coefficient and noise power under the block strategy.The K-means clustering algorithm is utilized to obtain the channel fading coefficient corresponding to the block mapping symbols,and this coefficient is used as the initial value for the EM algorithm,thereby facilitating rapid convergence.Finally,the intra-class modulation recognition of OFDM is realized by maximum likelihood(ML)classifier.The simulation and experimental results show that the proposed EM-Block-ML method can achieve highly reliable intraclass modulation recognition of OFDM in underwater acoustic multipath channel,verifying the effectiveness of the proposed recognition method.

关 键 词：类内调制识别 子载波信道模型 盲均衡 期望最大化 

分 类 号：TN929.3[电子电信—通信与信息系统]