RFID系统空中接口性能分析与编解码设计
摘要
RFID(无线射频识别)是一种自动的无线数据采集技术,其历史可以追溯到20世纪40年代的末期,随着集成电路和无线电技术的发展,RFID技术得到了巨大而又显著的进步。近年来,超高频(Ultra High Frequency UHF)射频识别系统在物流管理领域的应用中日益受到关注,但由于其应用环境一般非常恶劣,易受外界环境的干扰,严重影响了其大规模的商业应用,因此,对UHF RFID系统的研究和改进具有重要的意义。但是由于硬件开发设计周期长、制作过程复杂、费用昂贵、难以修改,可利用软件的开发设计来解决以上难题。
本文首先研究了ISO/IEC18000-6标准中A、B、C三类标准里所规定的前向链路和反向链路的调制解调模式以及数据的编码方式,对各种调制方式以及编码方式的信号特征进行了详细的分析,比较了振幅键控(ASK)、抑制载波的双边带振幅键控(DSB-ASK)、抑制载波的单边带振幅键控(SSB-ASK)、反向振幅键控(PR-ASK)、相移键控(PSK)的调制解调方法和这几种调制方式的优缺点,比较了脉冲间编码(PIE)、双向间隔编码(FM0)、曼彻斯特编码、Miller编码的编码方式及抗噪能力。然后,本文以虚拟仪器技术为基础,在LabVIEW软件平台上对这四种编码方式进行了编解码设计,在解码设计中用多点采样求平均值的方法来消除噪声影响,重点对易受噪声干扰的FM0编码做出了抗噪声解码的设计,以减小对滤波器设计的要求,并且模拟一段含干扰的数据来进行测试,事实证明软件设计能对数据快速地编码,并且能正确地解码来恢复信息。最后,分析了循环冗余校正码(CRC)的原理以及软件实现。本设计既可以应用于RFID测试系统,也可为商业RFID阅读器的设计提供参考,提高其准确性。
RFID (Radio-frequency identification) is an automatic wireless data-collection technology with a long history that can be traced back to the late 1940s. Since then, RFID has significantly advanced and experienced a tremendous growth due to developments in integrated circuits and radios. Recently, there are increased interesting in UHF RFID from many fields, such as logidtics, commerce and trade and so on. But it always working in a hostile environment, the readers are easily interfered by noise, therefore seriously influenced its large-scale commercial applications. Based on above reason, it's of great significance to the research and improvement of UHF RFID system. However, due to there are many shortage of hardware exploration, such as the long period for design, complicated procedure for manufacturing, expensive and difficulty for correction. Meanwhile, the software design can solve above problems.
The first, this paper investigates the forward link and return link data encoding method and modulation method according to types A, B and C in ISO/IEC18000-6, the power spectral dendity of modulation and encoding were characterized by analysis and calculation, and the advantages and disadvantages of ASK, DSB-ASK, SSB-ASK, PR-ASK and PSK, the antinoise ability and encoding methods of PIE, FMO, Manchester, Miller coding were compared. The second, based on the virtual instrument technology as the foundation, we designed the code-decode method on Lab VIEW, and in decoding design with multi-point sampling averaged method to eliminate noise effects, as the sensitive of FMO encoding, we gave a effective decode methord Specifically, it can reduce the design requirement of filter, and fially gave the result of testing of a data with noise. All of these facts prove software design for data quickly coding, and can correctly decoding to restore information. In the end, we analyse the principle and software realization of cyclic redundancy correction codes (CRC). This design can not only be applied to the RFID testing system, but also provide the reference for commercial RFID reader in order to improve its accuracy.
本文首先研究了ISO/IEC18000-6标准中A、B、C三类标准里所规定的前向链路和反向链路的调制解调模式以及数据的编码方式,对各种调制方式以及编码方式的信号特征进行了详细的分析,比较了振幅键控(ASK)、抑制载波的双边带振幅键控(DSB-ASK)、抑制载波的单边带振幅键控(SSB-ASK)、反向振幅键控(PR-ASK)、相移键控(PSK)的调制解调方法和这几种调制方式的优缺点,比较了脉冲间编码(PIE)、双向间隔编码(FM0)、曼彻斯特编码、Miller编码的编码方式及抗噪能力。然后,本文以虚拟仪器技术为基础,在LabVIEW软件平台上对这四种编码方式进行了编解码设计,在解码设计中用多点采样求平均值的方法来消除噪声影响,重点对易受噪声干扰的FM0编码做出了抗噪声解码的设计,以减小对滤波器设计的要求,并且模拟一段含干扰的数据来进行测试,事实证明软件设计能对数据快速地编码,并且能正确地解码来恢复信息。最后,分析了循环冗余校正码(CRC)的原理以及软件实现。本设计既可以应用于RFID测试系统,也可为商业RFID阅读器的设计提供参考,提高其准确性。
RFID (Radio-frequency identification) is an automatic wireless data-collection technology with a long history that can be traced back to the late 1940s. Since then, RFID has significantly advanced and experienced a tremendous growth due to developments in integrated circuits and radios. Recently, there are increased interesting in UHF RFID from many fields, such as logidtics, commerce and trade and so on. But it always working in a hostile environment, the readers are easily interfered by noise, therefore seriously influenced its large-scale commercial applications. Based on above reason, it's of great significance to the research and improvement of UHF RFID system. However, due to there are many shortage of hardware exploration, such as the long period for design, complicated procedure for manufacturing, expensive and difficulty for correction. Meanwhile, the software design can solve above problems.
The first, this paper investigates the forward link and return link data encoding method and modulation method according to types A, B and C in ISO/IEC18000-6, the power spectral dendity of modulation and encoding were characterized by analysis and calculation, and the advantages and disadvantages of ASK, DSB-ASK, SSB-ASK, PR-ASK and PSK, the antinoise ability and encoding methods of PIE, FMO, Manchester, Miller coding were compared. The second, based on the virtual instrument technology as the foundation, we designed the code-decode method on Lab VIEW, and in decoding design with multi-point sampling averaged method to eliminate noise effects, as the sensitive of FMO encoding, we gave a effective decode methord Specifically, it can reduce the design requirement of filter, and fially gave the result of testing of a data with noise. All of these facts prove software design for data quickly coding, and can correctly decoding to restore information. In the end, we analyse the principle and software realization of cyclic redundancy correction codes (CRC). This design can not only be applied to the RFID testing system, but also provide the reference for commercial RFID reader in order to improve its accuracy.
引文
[1]贾晓林.RFID技术的发展历史和标准现状.家电科技,2008,(19)：32-34
[2]蒋皓石,张成,林嘉宇.无线射频识别技术及其应用和发展趋势.电子技术应用,2005,31(5)：1-4
[3]沈宇超,沈树群.射频识别技术及其发展现状.电子技术应用,1999,(1)：4-5
[4]徐永成,罗日荣,陶利民等.射频识别技术国内外应用现状、问题与对策.测控技术,2008,27(11)：1-3
[5]Nikitin P V, Rao K V S. LabVIEW-based UHF RFID tag test and measurement system. Industrial Electronic,2009,56(7):2374-2377
[6]陈锡辉,张银鸿.LabVIEW 8.20程序设计从入门到精通.北京：清华大学出版社,2007,4-8
[7]慈新新,王苏滨,王硕.无线射频识别(RFID)系统技术与应用.北京：人民邮电出版社,2007,9-15
[8]谭民,刘禹,曾隽芳等.RFID技术系统工程及应用指南.北京：机械工业出版社,2007,11-16
[9]Khan M A, Sharma M, Prabhu R B. FSM based FMO and Miller encode for UHF RFID tag emulator. In:2009 IEEE International Advance Computing Conference. Patiala,2009,1317-1322
[10]ZOU Wen bin, WU Yun, ZHAO Yong. Automatic testing system for UHF passive RFID tag performance. In:Networking and Digital Society. Guiyang Guizhou. 2009,79-82
[11]ISO/IEC 18000-6. Radio frequency for item management, Part 6:Parameters for air interface communications at 860MHz to 960MHz. Switzerland:ISO/IEC, 2006,43-155
[12]张纲,杨庆森,程君侠等.ISO/IEC 18000-6(CD)研究综述.信息技术与标准化,2004,(4)：23-28
[13]EPC C1G2. EPCTM Radio-Frequency Identity Protocols Class-1 Generation-2 UHF RFID Protocol for Communications at 860 MHz～960MHz Version 1.0.9. USA:EPC Global,2005,51-55
[14]罗海勇,李锦涛,郭俊波等.新一代超高频RFID无线接口标准EPCCLASS-1/Gen-2研究.电子技术应用,2006,(5)：131-133
[15]周陈锋.基于Simulink的UHF RFID系统的数据传输分析与仿真：[湖南大学 硕士学位论文].长沙：湖南大学,2009,11-13
[16]Theodore S. Rappaport.无线通信原理与应用.蔡涛,李旭,杜振民译.北京：电子工业出版社,1999,163-165
[17]樊昌信,徐炳祥,吴成柯等.通信原理.北京：国防工业出版社,2002,123-142
[18]周晓光,王晓华.射频识别(RFID)技术原理与应用实例.北京：人民邮电出版社,2006,60-75
[19]胡乃英.UHF频段RFID空中接口协议的研究：[西北大学硕士学位论文].西安：西北大学,2008,33-35
[20]Liu Wei, Li Yongming, Zhang Chun, etal. Self-adaptive low-voltage current mode ASK demodulator for RFID tags.半导体技术,2009,34(1):10-11
[21]Jin Li, Cheng Tao. Analysis and simulation of UHF RFID system. In:Signal Processing,2006 8th International conference. Beijing,2006,1-5
[22]Wen Wei, Mendel, J M. Maximum-likelihood classification for digital amplitude-phase modulations. IEEE Transactions on Communications,2000,48(2): 189-193
[23]熊美英,李迟生,戴仁林.通信信号调制识别方法研究.现代电子技术,2007,30(15)：32-33
[24]袁杰,赵知劲,张福洪.基于FPGA的RFID调制解调器设计.电子器件,2008,31(5)：1636-1638
[25]高天宝,王敬超,张春等.超高频RFID读写器调制解调模块的设计.半导体学报,2008,29(7)：1403-1405
[26]谈熙,常若艇,闵昊等.超高频射频识别系统信号特征分析及应用.通信学报,2009,30(6)：89-94
[27]Hecht M, Guida A. Delay modulation. Proceedings of the IEEE,1969,57(7): 1314-1316
[28]林君勉,洪卫军,李书芳.射频识别系统的建模与特性分析.金卡工程(经济与法),2008,(6)：7-8
[29]Marco Chiani, Maria G. On sequential frame synchronization in AWGN channels. IEEE Transcations on communications,2006,54(2):339-342
[30]林艺文,方展伟.用FPGA实现曼彻斯特编解码.汕头大学学报(自然科学版),2004,19(2)：63-66
[31]王兰勋,张锁良.一种帧同步码检测方案及实现.河北大学学报(自然科学版),2004,24(2)：180-183
[32]胡莉,张力伟,周希元.帧同步检测技术的研究进展.无线电工程,2009, 39(2)：12-15
[33]江建军,杨彪,邵晖等.近高频射频识别读写器虚拟仪器系统设计与实现.仪器仪表学报,2007,28(6)：1024-1028
[34]Ayer N, Engels D W. Evalution of ISO 18000-6C artifacts. In:2009 IEEE International conference on RFID. Orlando,2009,123-127
[35]黄晨灵,刘圆,韩益锋.基于FPGA的RFID数字接收机的设计.计算机工程,2007,33(13)：230-232
[36]Sung Jin kim, Min Chang Cho, Joonhyun, etal. An ultra low power UHF RFID tag front-end for EPCglobal Gen2 with novel clock-free decoder. In:IEEE International Symposium on Circuits and System. Seattle,2008,660-663
[37]钟汉.超高频RFID阅读器基带信号解码方法.中国专利.200710027631,2007-09-19
[38]李鹏,高远,黄志敏等.RFID系统中基于ISO 18000-6的信号编解码设计.测绘信息与工程,2008,33(5)：92-93
[39]单承翰,柴斌.无源RFID中密勒码编解码技术与实现.通信与计算机,2004,(2)：37-39
[40]肖自铧,马琪,顾伟等.一种应用于超高频射频识别的密勒解码器.杭州电子科技大学学报,2008,28(6)：13-16
[41]邱祖江,郭亚炜,杨莲兴.一种改进Miller编解码的实现方法.微电子学,2000,30(3)：176-178
[42]Goth, G. RFID:not quite prime time, but dawdle at your own risk. Distributed Systems Online,2005,6(2):1-8
[43]杨梅娟,尹德春.CRC算法的研究.计算机与数字工程,2006,34(2)：30-32
[44]陈金平,王生泽,吴文英.基于LabVIEW的CRC检错码校验方法.自动化仪表,2004,25(5)：74-76
[45]Tung S, Jones A K. Physical layer design automation for RFID systems. In: Parallel and Distributed Processing,2008. IPDPS 2008. Miami,2008,1-8
[2]蒋皓石,张成,林嘉宇.无线射频识别技术及其应用和发展趋势.电子技术应用,2005,31(5)：1-4
[3]沈宇超,沈树群.射频识别技术及其发展现状.电子技术应用,1999,(1)：4-5
[4]徐永成,罗日荣,陶利民等.射频识别技术国内外应用现状、问题与对策.测控技术,2008,27(11)：1-3
[5]Nikitin P V, Rao K V S. LabVIEW-based UHF RFID tag test and measurement system. Industrial Electronic,2009,56(7):2374-2377
[6]陈锡辉,张银鸿.LabVIEW 8.20程序设计从入门到精通.北京：清华大学出版社,2007,4-8
[7]慈新新,王苏滨,王硕.无线射频识别(RFID)系统技术与应用.北京：人民邮电出版社,2007,9-15
[8]谭民,刘禹,曾隽芳等.RFID技术系统工程及应用指南.北京：机械工业出版社,2007,11-16
[9]Khan M A, Sharma M, Prabhu R B. FSM based FMO and Miller encode for UHF RFID tag emulator. In:2009 IEEE International Advance Computing Conference. Patiala,2009,1317-1322
[10]ZOU Wen bin, WU Yun, ZHAO Yong. Automatic testing system for UHF passive RFID tag performance. In:Networking and Digital Society. Guiyang Guizhou. 2009,79-82
[11]ISO/IEC 18000-6. Radio frequency for item management, Part 6:Parameters for air interface communications at 860MHz to 960MHz. Switzerland:ISO/IEC, 2006,43-155
[12]张纲,杨庆森,程君侠等.ISO/IEC 18000-6(CD)研究综述.信息技术与标准化,2004,(4)：23-28
[13]EPC C1G2. EPCTM Radio-Frequency Identity Protocols Class-1 Generation-2 UHF RFID Protocol for Communications at 860 MHz～960MHz Version 1.0.9. USA:EPC Global,2005,51-55
[14]罗海勇,李锦涛,郭俊波等.新一代超高频RFID无线接口标准EPCCLASS-1/Gen-2研究.电子技术应用,2006,(5)：131-133
[15]周陈锋.基于Simulink的UHF RFID系统的数据传输分析与仿真：[湖南大学 硕士学位论文].长沙：湖南大学,2009,11-13
[16]Theodore S. Rappaport.无线通信原理与应用.蔡涛,李旭,杜振民译.北京：电子工业出版社,1999,163-165
[17]樊昌信,徐炳祥,吴成柯等.通信原理.北京：国防工业出版社,2002,123-142
[18]周晓光,王晓华.射频识别(RFID)技术原理与应用实例.北京：人民邮电出版社,2006,60-75
[19]胡乃英.UHF频段RFID空中接口协议的研究：[西北大学硕士学位论文].西安：西北大学,2008,33-35
[20]Liu Wei, Li Yongming, Zhang Chun, etal. Self-adaptive low-voltage current mode ASK demodulator for RFID tags.半导体技术,2009,34(1):10-11
[21]Jin Li, Cheng Tao. Analysis and simulation of UHF RFID system. In:Signal Processing,2006 8th International conference. Beijing,2006,1-5
[22]Wen Wei, Mendel, J M. Maximum-likelihood classification for digital amplitude-phase modulations. IEEE Transactions on Communications,2000,48(2): 189-193
[23]熊美英,李迟生,戴仁林.通信信号调制识别方法研究.现代电子技术,2007,30(15)：32-33
[24]袁杰,赵知劲,张福洪.基于FPGA的RFID调制解调器设计.电子器件,2008,31(5)：1636-1638
[25]高天宝,王敬超,张春等.超高频RFID读写器调制解调模块的设计.半导体学报,2008,29(7)：1403-1405
[26]谈熙,常若艇,闵昊等.超高频射频识别系统信号特征分析及应用.通信学报,2009,30(6)：89-94
[27]Hecht M, Guida A. Delay modulation. Proceedings of the IEEE,1969,57(7): 1314-1316
[28]林君勉,洪卫军,李书芳.射频识别系统的建模与特性分析.金卡工程(经济与法),2008,(6)：7-8
[29]Marco Chiani, Maria G. On sequential frame synchronization in AWGN channels. IEEE Transcations on communications,2006,54(2):339-342
[30]林艺文,方展伟.用FPGA实现曼彻斯特编解码.汕头大学学报(自然科学版),2004,19(2)：63-66
[31]王兰勋,张锁良.一种帧同步码检测方案及实现.河北大学学报(自然科学版),2004,24(2)：180-183
[32]胡莉,张力伟,周希元.帧同步检测技术的研究进展.无线电工程,2009, 39(2)：12-15
[33]江建军,杨彪,邵晖等.近高频射频识别读写器虚拟仪器系统设计与实现.仪器仪表学报,2007,28(6)：1024-1028
[34]Ayer N, Engels D W. Evalution of ISO 18000-6C artifacts. In:2009 IEEE International conference on RFID. Orlando,2009,123-127
[35]黄晨灵,刘圆,韩益锋.基于FPGA的RFID数字接收机的设计.计算机工程,2007,33(13)：230-232
[36]Sung Jin kim, Min Chang Cho, Joonhyun, etal. An ultra low power UHF RFID tag front-end for EPCglobal Gen2 with novel clock-free decoder. In:IEEE International Symposium on Circuits and System. Seattle,2008,660-663
[37]钟汉.超高频RFID阅读器基带信号解码方法.中国专利.200710027631,2007-09-19
[38]李鹏,高远,黄志敏等.RFID系统中基于ISO 18000-6的信号编解码设计.测绘信息与工程,2008,33(5)：92-93
[39]单承翰,柴斌.无源RFID中密勒码编解码技术与实现.通信与计算机,2004,(2)：37-39
[40]肖自铧,马琪,顾伟等.一种应用于超高频射频识别的密勒解码器.杭州电子科技大学学报,2008,28(6)：13-16
[41]邱祖江,郭亚炜,杨莲兴.一种改进Miller编解码的实现方法.微电子学,2000,30(3)：176-178
[42]Goth, G. RFID:not quite prime time, but dawdle at your own risk. Distributed Systems Online,2005,6(2):1-8
[43]杨梅娟,尹德春.CRC算法的研究.计算机与数字工程,2006,34(2)：30-32
[44]陈金平,王生泽,吴文英.基于LabVIEW的CRC检错码校验方法.自动化仪表,2004,25(5)：74-76
[45]Tung S, Jones A K. Physical layer design automation for RFID systems. In: Parallel and Distributed Processing,2008. IPDPS 2008. Miami,2008,1-8