一种改进的星载AIS信号非相干解调算法  

An Improved Non-coherent Demodulation Algorithm for Satellite-based AIS Signals

作　　者：程欢[1,2] 王小华[1] 曹志锋[1] 

机构地区：[1]长沙理工大学电气与信息工程学院,长沙410015 [2]镇江船艇学院,江苏镇江212003

出　　处：《电讯技术》2014年第2期169-173,共5页Telecommunication Engineering

摘　　要：针对星载船舶自动识别系统（AIS）无法避免的信号混叠问题,研究了AIS系统中应用最广泛的1比特差分和2比特差分解调,提出了一种1、2、3比特联合差分反馈的AIS信号非相干解调算法.该算法基于贝叶斯线性模型建立了最大似然估计的1、2、3比特联合差分解调结构,验证了在加性高斯信道中该算法比传统非相干解调算法有更好的抗信号混叠能力.仿真实验表明：该算法的解调误码率与1、2比特联合差分及2、3比特联合差分相比,当误码率（BER）等于10-2时,在加性高斯信道（AWGN）下具有1.5dB的性能优势,同道干扰信道（CCI）下具有1~2dB的性能优势.关键词：星载AIS;非相干解调;差分反馈;A non-coherent algorithm based on combined 1, 2 and 3-bit differential detection with decisionfeedback is proposed in this paper to demodulate AIS （Automatic Identification System） signals, so as toenhance the abilities of the widely-used 1 and 2-bit differential detection ones in adaptation to co-channelinterference（CCI）. The algorithm is based on the Bayesian linear model, and establishes a maximum likelihood detection formulation. Theoretical analysis demonstrates the predominance of the proposed algorithmagainst the existing non-coherent counterparts in adaption to CCI. Simulation results then show that, whencompared with the two algorithms developed via 1 and 2-bit joint differential detection and 2 and 3-bitjoint differential detection with the bit error rate（BER） is set to 10-2, the proposed algorithm gains an improvement of 1. 5 dB in signal - to - noise ratio （SNR） in the case of additive white Gaussian noise（AWGN）, and an improvement of 1 ~2 dB in signal-to-interference ratio （SIR）.

关 键 词：星载AIS 非相干解调 差分反馈 误码率分析 

分 类 号：TN924[电子电信—通信与信息系统]