【作者】 王素芬；

【导师】 刘智；

【作者基本信息】 长春理工大学 ， 电子与通信工程（专业学位）， 2018， 硕士

【摘要】 激光通信因其速率高、通信容量大、抗干扰能力强,保密性能好,带宽非常宽等优点,在各个领域得到了广泛应用。由于大气信道中大气吸收和散射及大气湍流运动等的影响,会导致链路误码率增大、速率降低、数据丢失,甚至会导致链路中断。信道编码技术具有较强的差错控制能力,能有效缓解大气湍流效应等所带来的影响,从而大大降低了通信传输的误码率,改善通信系统的可靠性。LDPC因为性能逼近Shannon理论极限、结构灵活、可并行操作、编译码复杂度低和适合硬件实现等优点,在大气激光通信系统中得到广泛的应用。本文针对大气激光通信系统中的LDPC码开展研究,在分析了激光大气传输基本理论的基础上,对大气激光通信系统中信道编码的现状,编译码的方法进行系统了描述,着重对LDPC码的编译码原理进行了深入细致的研究和分析,采用矩阵分裂技术和掩码技术对LDPC进行了编码,并设计构建了实验大气激光通信系统,将LDPC码和传统的编码方式对误码率的改善情况进行了野外实验验证,并把实验的验证结果同理论仿真结果进行了对比分析。分析结果表明,采用LDPC编译码方法能够对大气激光通信系统通信过程中的误码进行有效地差错控制。在相同的信道条件下,采用优化后的LDPC码比传统的信道编码的纠错性能高,仿真结果与实验结果基本一致。更多还原

【Abstract】 Laser communication has been widely used in various fields due to its high speed,large communication capacity,strong anti-interference ability,good security performance,wide bandwidth.Due to atmospheric absorption and atmospheric scattering and atmospheric turbulence movement,etc.,the link error rate will increase,the rate will decrease,the data loss,and even the link will be interrupted.The channel coding technology has strong error control capabilities,can effectively mitigate the effects of atmospheric turbulence effects,etc.,thereby greatly reducing the error rate of communication transmission and improving the reliability and stability of the communication system.At present,channel codes commonly used in the atmosphere include RS codes,Turbo codes,and LDPC codes.LDPC has been widely used in atmospheric laser communication systems because of its advantages of approaching Shannon’s theoretical limit,flexible structure,low error leveling,parallel operation,low coding and decoding complexity,and hardware implementation.This paper studies the LDPC codes in atmospheric laser communication systems.Based on the analysis of the basic theory of laser atmospheric transmission,the present situation of channel coding in atmospheric laser communication system and the method of encoding and decoding are systematically described.The principle of encoding and decoding of LDPC codes is studied and analyzed in detail,and the matrix is adopted.The splitting technique and masking technique are used to encode LDPC,and an experimental atmospheric laser communication system is designed and constructed.The BERC code and traditional coding methods are tested in field experiments to improve the BER,and the experimental verification results are obtained.The theoretical simulation results were compared and analyzed.Under the same channel conditions,the optimized LDPC code has higher error correction performance than traditional channel coding.The simulation results are basically consistent with the experimental results.更多还原