摘要
北京S1线车地通信的信息帧仅有128 bit,需在消耗尽量少校验位的同时,拥有较高的信息检错能力。首先介绍了CRC漏检原理;其次基于BSC信道,针对包含数据位、校验位在内的128 bit信息帧,采用概率方法,对CRC-24(0x1974f0b)与IEEE 802.3中CRC-32(0x104c11db7)的检错能力,进行了定量对比;最后使用误码率的离散点进行分析计算,用极限运算证明了分析结论在低误码率时均成立。理论分析和实验均表明:在128 bit信息帧场景下,若BSC信道误码率低于2.83841×10-5,CRC-24(0x1974f0b)不但比CRC-32(0x104c11db7)少消耗8 bit校验位,同时还能提供更优的检错能力,且误码率越低优势越显著。因此,在实践中选择CRC生成多项式时,应综合考虑信道误码率、数据位bit数、以及对检错能力的要求等。
The information frame of Beijing S1 line train-wayside communication system,with only has 128 bits,requires both low check bits consumption and high error check ability.Firstly,CRC miss checking principle was introduced.Then a BSC-based quantitative comparison on error check ability of CRC-24(0x1974f0b)and CRC-32(0x104c11db7),which were used in IEEE 802.3,in 128 bits frame(including data bits and CRC bits)was done via probability methods.The analysis calculation used discrete bit error ratio(e)value,and limit operation demonstrated that the analysis conclusion is always true with low bit error ratio.Theoretical analysis and experiments show that CRC-24(0x1974f0b)not only consumes 8 fewer check bits than CRC-32(0x104c11db7),but also provides better error check ability and the lower e along with the better error check ability,in 128 bits frame,when e<2.83841×10-5.Therefore,in practice,the number of data bits,bit error ratio,and error check ability requirement should be considered comprehensively when choosing CRC generator polynomial.
作者
吴炳昊
董俊超
阮秋琦
WU Binghao;DONG Junchao;RUAN Qiuqi(CRSC Research & Design Institute Group Co.,Ltd.,Beijing 100070,China;CRSC Urban Rail Transit Technology Co.,Ltd.,Beijing 100070,China;Institute of Information Science, Beijing Jiaotong University, Beijing 100081,China)
出处
《铁道学报》
EI
CAS
CSCD
北大核心
2021年第1期115-121,共7页
Journal of the China Railway Society
