卷积码在井下电缆高速传输系统中的性能研究  

Performance of Convolution Coding in Downhole Cable High-speed Transmission System

作　　者：程星 刘得军[1] 张自成[2] 徐瑨 房华锋 CHENG Xing;LIU Dejun;ZHANG Zicheng;XU Jin;FANG Huafeng(College of Geophysics and Information Engineering,China University of Petroleum (Beijing),Beijing 102249,China;Logging & Testing Services Company,Daqing Oilfield Limited Company,Daqing 163453,Heilongjiang,China)

机构地区：[1]中国石油大学(北京)地球物理与信息工程学院,北京102249 [2]大庆油田有限责任公司测试技术服务分公司,黑龙江大庆163453

出　　处：《西安石油大学学报（自然科学版）》2017年第6期119-123,共5页Journal of Xi’an Shiyou University（Natural Science Edition）

基　　金：国家自然科学基金项目(41374151);国家重大科研装备研制项目"深部资源探测核心装备研发"(ZDYZ2012-1)-07子项目"深部矿床测井系统-02-01课题井下高速电缆传输系统研制"

摘　　要：测井电缆是典型的频率选择性衰落信道,其有效带宽窄,对频率100 k Hz以上的信号衰减严重。为提高井下高速电缆传输系统的抗误码能力,通常引入纠错能力较强的卷积编码技术。针对测井电缆信道特性,提出一种能够调整编码约束度与译码深度的混合卷积编码方案,并在FPGA上实现卷积编译码。仿真结果表明,卷积编码约束度越长,系统误比特率越低,但译码时间增长得更快;随着译码深度的增加,系统误比特率减小得不明显,但译码时间呈线性增加;与单一参数的卷积编码相比,所提出的混合卷积编码方案能获得更高的编码增益,且译码时间减小31%以上,实现了纠错性能与编译码复杂度的最优化。The logging cable is a typical selective frequency fading channel,its effective bandwidth is narrow,and there are serious attenuation to the signals whose frequency are above100kHz.In order to improve the error resilience of downhole high-speed cable transmission system,generally a forward error correction coding technology is introduced into the system.According to the channel characteristics of well logging cable,a hybrid convolutional coding scheme that can adjust coding constraint degree and decoding depth is proposed,and convolutional encoding and decoding is realized on FPGA.The simulation results show that the longer the constraint degree of convolutional coding is,the lower the bit error rate of the system is,but the decoding time grow faster;with the increase of decoding depth,the reduction of the bit error rate is not obvious,but the decoding time increases linearly;compared with convolutional encoding with single parameter,the proposed hybrid convolution encoding scheme can achieve higher encoding gain,the decoding time is reduced by more than31%,and the optimization of error correction performance and coding and decoding complexity is achieved.

关 键 词：正交频分复用 卷积码 维特比译码 FPGA 

分 类 号：TN911[电子电信—通信与信息系统]