基于OCDM的光网络中两项关键技术研究
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摘要
光码分多址(OCDMA)技术是CDMA技术与光纤通信的融合,具有抗干扰、用户随机接入、管理方便、优良的安全性能等优点。光码分复用(OCDM)在光域对各路信号进行编码和解码,对用户数据进行全光信号处理,是实现真正意义上的全光通信最有希望的多址复用技术之一。本文对基于OCDM的光网络技术进行研究,主要包括基于OCDM的光分插复用器(OADM)研究和基于OCDM的OPS(光分组交换)研究两部分,具体工作内容如下:
(1)把光硬限幅器引入到现有基于OCDM的OADM结构中,使用马尔科夫链模型和状态转移概率矩阵,得到基于这种OADM的环网中各用户的误码率表达式。计算表明,基于OCDM的OADM中下路单元(即码字消除单元Code Drop Unit)虽然能够有效地把码字从环网中消除掉,避免码字在环网中循环产生干扰累加,但是会明显恶化经过下路单元的其它用户的误码率。论文中还讨论了基于这种OADM的环网中用户的误码率与码长、判决阈值的关系。最后,提出了一种基于误码率监测及反馈的方法,来降低下路单元造成的误码率恶化。仿真结果表明,该方法能有效改善用户的误码率性能。
(2)结合一种基于OCDM的OPS系统模型,重点研究了作为OPS标签的四相OCDM码的生成方法、相关值及其分布、实现,理论分析了基于四相OCDM码的OPS系统分组间干扰的影响。通过仿真比较了码长为63和127的四相OCDM码OPS系统和光正交码OCDM的OPS系统的性能,仿真结果表明,四相码OCDM字更适合作为基于OCDM的OPS系统的标签。
OCDMA is an integration of CDMA and optical fiber communication. It offers several unique advantages, such as strong resistance against interference, asynchronous accessing, convenient management, strong security performance and so on. Due to the user’s data is coded and decoded by all-optical signal processing, OCDM is regarded as a most promising technology to relize all-optical communication. This paper presents theoretical research on OADM and OPS based on OCDM technology.The main contents are given as following:
(1) Optical hard limiter is introduced into the structure of OADM base on OCDM. The code drop unit in OCDM ring networks is analyzed. Expressions of BER performance of every user are obtained by using Markov Chain model and state transition probability matrix. The results show that even though code drop unit removes the code effectively from the ring network, it will deteriorate the BER performance of other users. The relation between BER performance and code length, code weight is analyzed in detail. After that, we propose an OCDM ring network access control method which can improve the network’s BER performance by BER monitoring and feedback, with chip time control and codes random selection. Simulation result shows that the method can efficiently improve the BER performance of users in the OCDM ring network.
(2) An OPS system model is introduced. The generation method, correlation, correlation distribution and coder/decoder of 4-phase OCDM codes are studied. The performance of interference between optical packets is analyzed. The performance of systems based on 4-phase OCDM with code length 127 and 63is simulated. The result shows that 4-phase OCDM codes is regards as a better label in OPS based on OCDM.
(1)把光硬限幅器引入到现有基于OCDM的OADM结构中,使用马尔科夫链模型和状态转移概率矩阵,得到基于这种OADM的环网中各用户的误码率表达式。计算表明,基于OCDM的OADM中下路单元(即码字消除单元Code Drop Unit)虽然能够有效地把码字从环网中消除掉,避免码字在环网中循环产生干扰累加,但是会明显恶化经过下路单元的其它用户的误码率。论文中还讨论了基于这种OADM的环网中用户的误码率与码长、判决阈值的关系。最后,提出了一种基于误码率监测及反馈的方法,来降低下路单元造成的误码率恶化。仿真结果表明,该方法能有效改善用户的误码率性能。
(2)结合一种基于OCDM的OPS系统模型,重点研究了作为OPS标签的四相OCDM码的生成方法、相关值及其分布、实现,理论分析了基于四相OCDM码的OPS系统分组间干扰的影响。通过仿真比较了码长为63和127的四相OCDM码OPS系统和光正交码OCDM的OPS系统的性能,仿真结果表明,四相码OCDM字更适合作为基于OCDM的OPS系统的标签。
OCDMA is an integration of CDMA and optical fiber communication. It offers several unique advantages, such as strong resistance against interference, asynchronous accessing, convenient management, strong security performance and so on. Due to the user’s data is coded and decoded by all-optical signal processing, OCDM is regarded as a most promising technology to relize all-optical communication. This paper presents theoretical research on OADM and OPS based on OCDM technology.The main contents are given as following:
(1) Optical hard limiter is introduced into the structure of OADM base on OCDM. The code drop unit in OCDM ring networks is analyzed. Expressions of BER performance of every user are obtained by using Markov Chain model and state transition probability matrix. The results show that even though code drop unit removes the code effectively from the ring network, it will deteriorate the BER performance of other users. The relation between BER performance and code length, code weight is analyzed in detail. After that, we propose an OCDM ring network access control method which can improve the network’s BER performance by BER monitoring and feedback, with chip time control and codes random selection. Simulation result shows that the method can efficiently improve the BER performance of users in the OCDM ring network.
(2) An OPS system model is introduced. The generation method, correlation, correlation distribution and coder/decoder of 4-phase OCDM codes are studied. The performance of interference between optical packets is analyzed. The performance of systems based on 4-phase OCDM with code length 127 and 63is simulated. The result shows that 4-phase OCDM codes is regards as a better label in OPS based on OCDM.
引文
[1] 李传起,孙小菡.OCDMA 系统地址码理论.合肥:中国科技大学出版社,2005:109-115
[2] Seo S W.Transparent optical networks with time-division multiplexing. IEEE J Select Areas Communication,1996,14:1039-1051
[3] Brackett C A.Dense wavelength division multiplexing networks:Principle and application.IEEE J Selected Areas Communication,1990,8:948-964
[4] Hui,J Y.Pattern code modulation and optical decoding-a novel code-division multiplexing technique for multifiber network. IEEE J Selected Areas Communication,,1985,3(6):916-927
[5] Salehi J A,Brackett C A.Code Division Multiple-Acess Techniques in Optical Fiber Network –Part I Fundamental Principle.IEEE Transaction on Communication,1989,37(8):824-833
[6] Salehi J A,Brackett C A.Code Division Multiple-Acess Techniques in Optical Fiber Network -Part II:System performance analysis.IEEE Transaction on Communication,1989,37(8):834-842
[7] Sok A,Sargent E H.Lighting the local network:Optical code division multiple access and quality of services provisioning.IEEE Network, 2000, 14(6): 42-46
[8] H,Rusch L A.Robust optical FFH-CDMA communications:Coding in place of frequency and temperature controls.Journal of Lightwave Techology,1999,17(8):1284～1293
[9] Davies, P. A.; Shaar, A. A.Asynchronous multiplexing for an optical-fibre local-area network,Electronics Letters,1983,19(10):3900-392
[10] Park E.Temporal/spatial codes for asynchronous fiber optic CDMA network : Design ,demonstration comparison with temporal network.IEEE Photonics Technology Letters,1992,4(10):1160-1162
[11] Yang G C,Kwong C.Performance comparison of multiwavelength CDMA and WDMA+CDMA for fiber optic networks.IEEE Transaction on Communication , 1997, 45(11):1426-1436
[12] Chang T W F,Sargent E H.Optical CDMA using 2-D codes:the optimal single-user detector.IEEE Communication Letters,2001,5(4):169-171
[13] Min, Seong-Sik; Yoo, Hark; Won, Yong.Time-wavelength hybrid optical CDMA system with tunable encoder/decoder using switch and fixed delay-line.Opticscommunications,2003,216(4-6):335-342
[14] Jun S Y,Kim Y I,Lee C H.Design concept of an CDMA system with optical fiber delay line.CLEO/Pacific99:515-516
[15] Griffin R A,Sampson D D,Jackson D A.Modification of optical coherence using spectral phase coding for use in photonic code-division multiple access systems.Electronics Letter,1993,29(25):2214-2216
[16] David M M,Ara V D.Superimposed Fiber Bragg Grating Simulation by the Method of Single Expression for Optical CDMA system.IEEE Photonics Technology Letters,2003, 15(11):1546-1548
[17] Jepsen A G,Johnson A E,Maniloff E S.Fiber Bragg grating based spectral encoder/decoder for lightwave CDMA.Electronics Letters,1999,35(13):1096-1097
[18] Teixeira, Antonio. All optical router based on OCDMA codes and SOA based devices. ICTON 2005, 2005,:183-188
[19] Wang X,Wada N.Demonstration of OCDMA traffic over optical packet switching with PLC and SSFBG endecoders for time domain OC processing.ECOC2005,2005:357-358
[20] P Seddighian, S. Ayotte, Label stacking using spectral amplitude code labels for optical packet switching. OFC 2006,2006
[21] Xuehong Zhang, Yuefeng Ji, Xue Chen,Code routing technique in optical network, APCC/OECC '99,1999,1: 416-419
[22] C S. Bres, I. Glesk, R. J. Runser,et al, "All-optical OCDMA code-drop unit for transparent ring networks"[J], IEEE Photon. Technol. Lett, vol. 17(5), 2005: 1088-1090
[23] F.Chung. Optical Orthogonal Codes: Desigh, Analysis and Applications. IEEE Trans.,1989, 35(6):595-604
[24] L.Tancevski. Wavelength hopping/time spreading code division multiple access systems. Electron Lett, 1994, 18(8): 1388-1390
[25] L.S.Holmes, R.R. Syms. All-optical cdma using quasi-prime codes. IEEE Journal of Lightwave Technology, 1992., 10(2): 279-286
[26] Jian-Guo Zhang, Wing C.Kwong, A.B.Sharma. 2n modified prime codes for use in fibre optic CDMA networks. Electronics Letters, 1997, 33(22): 1840-1841
[27] S.V.Maric. New family of algebraically designed optical orthogonal codes for use in CDMA fibre-optic networks. Electronics Letters, 1993, 29(6):538-539
[28] L.Bin. One-conincidence sequence with specified distance between adjacent symbols of frequency-hopping multiple access. J.Lightwave Tech., 1999, 17(4):570-578
[29] Zaccarin, M.Kavehrad. New architecture for incoherent optical CDMA to achieve bipolar capacity. Electronics Letters, 1994, 30(3):258-259
[30] C.Chang, H.P.Sardesai, A.M.Weiner. Code-Division Multiple-Access Encoding and Decoding of Fem to second Optical Pulses over a 2.5-km Fiber Link. IEEE Photonics Tech.Lett, 1998, 10(1):171-174
[31] Xu Wang, Keys Towards Practical OCDMA Networks[A] IEEE International Conference on Optoelectronics, Fiber Optics and Photonics (Photonics 2004)[C], December 2004.
[32] 吉建华, 徐铭, 杨淑雯, 等.采用光硬限幅器和 RS 码的多波长 OCDMA 性能分析[J].光电子·激光,2005,16 (11) :1312-1315
[33] FU Xiao-mei; YU Jin-long; WANG Wen-rui, et al, The Characteristics of Two-dimension Optical Othrogonal Code Encoding OCDMA Communication with Bragg Gragting Arrays, [J]. Journal of Optoelectronics·Laser(光电子·激光)16(12),2005:1259-1260(in Chinese)
[34] Sharon Goldbergy, Varghese Babyy,Ting Wangz,et al.Source-Matched Spreading Codes for Optical CDMA[J/OL]. www.princeton.edu/~goldbe/Goldberg_Puncturing.pdf 2006[2006-6-23]
[35] JI Jian-hua, XU Ming, YANG Shu-wen , et al. Performance Analysis of Multi-wavelength OCDMA Employing Optical Hard-limiters and RS Code [J]. Journal of Optoelectronics·Laser(光电子·激光)16 (11) ,2005, :1312-1315(in Chinese)
[36] 邵嘉裕 .组合数学.上海:同济大学出版社.1991:54-56
[37] S. Boztas and P.V.Kumar. 4-phase sequences with near-optimum correlation properties. IEEE Trans. Inform.Theory, 1992, IT-38: 1101~1113
[38] L.R.Welch. Lower bounds on the maximum cross correlation of signals. IEEE Transactions of Information Theory, 1974, IT-20(3): 397~399
[39] 范平志. 广义正交信号理论及其应用. 计算机与信息技术, 1999, 24(5): 33-38
[40] Chung F R K, Salehi J A, Wei V K. Optical orthogonal codes:design, analysis and applications[J]. IEEE Trans Inform Theory, 1989, 35(3): 595-604
[41] 艾兴芳. 基于 6.4Tbit/s 传输系统的光码分复用技术研究:[硕士学位论文].武汉:华中科技大学,2004
[42] 樊昌信,张甫翊,徐炳祥,等.通信原理.北京:国防工业出版社,2001,328-329
[43] 朱近康. 扩展频谱通信及其应用. 合肥:中国科技大学出版社,1993
[44] 顾畹仪,李国瑞. 光纤通信系统. 北京:北京邮电大学出版社,1999
[45] H. Lundqvist and G. Karlsson. On Error-Correction Coding for CDMA PON. Journal of Lightwave Technology, 23(8), 2005, 2342-2351
[46] A. Srivastava, S. Kar, V.K. Jain. Forward error correcting codes in fiber-optic synchronous code-division multiple access networks, Optical Communications, v202, 2002, 287-296
[2] Seo S W.Transparent optical networks with time-division multiplexing. IEEE J Select Areas Communication,1996,14:1039-1051
[3] Brackett C A.Dense wavelength division multiplexing networks:Principle and application.IEEE J Selected Areas Communication,1990,8:948-964
[4] Hui,J Y.Pattern code modulation and optical decoding-a novel code-division multiplexing technique for multifiber network. IEEE J Selected Areas Communication,,1985,3(6):916-927
[5] Salehi J A,Brackett C A.Code Division Multiple-Acess Techniques in Optical Fiber Network –Part I Fundamental Principle.IEEE Transaction on Communication,1989,37(8):824-833
[6] Salehi J A,Brackett C A.Code Division Multiple-Acess Techniques in Optical Fiber Network -Part II:System performance analysis.IEEE Transaction on Communication,1989,37(8):834-842
[7] Sok A,Sargent E H.Lighting the local network:Optical code division multiple access and quality of services provisioning.IEEE Network, 2000, 14(6): 42-46
[8] H,Rusch L A.Robust optical FFH-CDMA communications:Coding in place of frequency and temperature controls.Journal of Lightwave Techology,1999,17(8):1284～1293
[9] Davies, P. A.; Shaar, A. A.Asynchronous multiplexing for an optical-fibre local-area network,Electronics Letters,1983,19(10):3900-392
[10] Park E.Temporal/spatial codes for asynchronous fiber optic CDMA network : Design ,demonstration comparison with temporal network.IEEE Photonics Technology Letters,1992,4(10):1160-1162
[11] Yang G C,Kwong C.Performance comparison of multiwavelength CDMA and WDMA+CDMA for fiber optic networks.IEEE Transaction on Communication , 1997, 45(11):1426-1436
[12] Chang T W F,Sargent E H.Optical CDMA using 2-D codes:the optimal single-user detector.IEEE Communication Letters,2001,5(4):169-171
[13] Min, Seong-Sik; Yoo, Hark; Won, Yong.Time-wavelength hybrid optical CDMA system with tunable encoder/decoder using switch and fixed delay-line.Opticscommunications,2003,216(4-6):335-342
[14] Jun S Y,Kim Y I,Lee C H.Design concept of an CDMA system with optical fiber delay line.CLEO/Pacific99:515-516
[15] Griffin R A,Sampson D D,Jackson D A.Modification of optical coherence using spectral phase coding for use in photonic code-division multiple access systems.Electronics Letter,1993,29(25):2214-2216
[16] David M M,Ara V D.Superimposed Fiber Bragg Grating Simulation by the Method of Single Expression for Optical CDMA system.IEEE Photonics Technology Letters,2003, 15(11):1546-1548
[17] Jepsen A G,Johnson A E,Maniloff E S.Fiber Bragg grating based spectral encoder/decoder for lightwave CDMA.Electronics Letters,1999,35(13):1096-1097
[18] Teixeira, Antonio. All optical router based on OCDMA codes and SOA based devices. ICTON 2005, 2005,:183-188
[19] Wang X,Wada N.Demonstration of OCDMA traffic over optical packet switching with PLC and SSFBG endecoders for time domain OC processing.ECOC2005,2005:357-358
[20] P Seddighian, S. Ayotte, Label stacking using spectral amplitude code labels for optical packet switching. OFC 2006,2006
[21] Xuehong Zhang, Yuefeng Ji, Xue Chen,Code routing technique in optical network, APCC/OECC '99,1999,1: 416-419
[22] C S. Bres, I. Glesk, R. J. Runser,et al, "All-optical OCDMA code-drop unit for transparent ring networks"[J], IEEE Photon. Technol. Lett, vol. 17(5), 2005: 1088-1090
[23] F.Chung. Optical Orthogonal Codes: Desigh, Analysis and Applications. IEEE Trans.,1989, 35(6):595-604
[24] L.Tancevski. Wavelength hopping/time spreading code division multiple access systems. Electron Lett, 1994, 18(8): 1388-1390
[25] L.S.Holmes, R.R. Syms. All-optical cdma using quasi-prime codes. IEEE Journal of Lightwave Technology, 1992., 10(2): 279-286
[26] Jian-Guo Zhang, Wing C.Kwong, A.B.Sharma. 2n modified prime codes for use in fibre optic CDMA networks. Electronics Letters, 1997, 33(22): 1840-1841
[27] S.V.Maric. New family of algebraically designed optical orthogonal codes for use in CDMA fibre-optic networks. Electronics Letters, 1993, 29(6):538-539
[28] L.Bin. One-conincidence sequence with specified distance between adjacent symbols of frequency-hopping multiple access. J.Lightwave Tech., 1999, 17(4):570-578
[29] Zaccarin, M.Kavehrad. New architecture for incoherent optical CDMA to achieve bipolar capacity. Electronics Letters, 1994, 30(3):258-259
[30] C.Chang, H.P.Sardesai, A.M.Weiner. Code-Division Multiple-Access Encoding and Decoding of Fem to second Optical Pulses over a 2.5-km Fiber Link. IEEE Photonics Tech.Lett, 1998, 10(1):171-174
[31] Xu Wang, Keys Towards Practical OCDMA Networks[A] IEEE International Conference on Optoelectronics, Fiber Optics and Photonics (Photonics 2004)[C], December 2004.
[32] 吉建华, 徐铭, 杨淑雯, 等.采用光硬限幅器和 RS 码的多波长 OCDMA 性能分析[J].光电子·激光,2005,16 (11) :1312-1315
[33] FU Xiao-mei; YU Jin-long; WANG Wen-rui, et al, The Characteristics of Two-dimension Optical Othrogonal Code Encoding OCDMA Communication with Bragg Gragting Arrays, [J]. Journal of Optoelectronics·Laser(光电子·激光)16(12),2005:1259-1260(in Chinese)
[34] Sharon Goldbergy, Varghese Babyy,Ting Wangz,et al.Source-Matched Spreading Codes for Optical CDMA[J/OL]. www.princeton.edu/~goldbe/Goldberg_Puncturing.pdf 2006[2006-6-23]
[35] JI Jian-hua, XU Ming, YANG Shu-wen , et al. Performance Analysis of Multi-wavelength OCDMA Employing Optical Hard-limiters and RS Code [J]. Journal of Optoelectronics·Laser(光电子·激光)16 (11) ,2005, :1312-1315(in Chinese)
[36] 邵嘉裕 .组合数学.上海:同济大学出版社.1991:54-56
[37] S. Boztas and P.V.Kumar. 4-phase sequences with near-optimum correlation properties. IEEE Trans. Inform.Theory, 1992, IT-38: 1101~1113
[38] L.R.Welch. Lower bounds on the maximum cross correlation of signals. IEEE Transactions of Information Theory, 1974, IT-20(3): 397~399
[39] 范平志. 广义正交信号理论及其应用. 计算机与信息技术, 1999, 24(5): 33-38
[40] Chung F R K, Salehi J A, Wei V K. Optical orthogonal codes:design, analysis and applications[J]. IEEE Trans Inform Theory, 1989, 35(3): 595-604
[41] 艾兴芳. 基于 6.4Tbit/s 传输系统的光码分复用技术研究:[硕士学位论文].武汉:华中科技大学,2004
[42] 樊昌信,张甫翊,徐炳祥,等.通信原理.北京:国防工业出版社,2001,328-329
[43] 朱近康. 扩展频谱通信及其应用. 合肥:中国科技大学出版社,1993
[44] 顾畹仪,李国瑞. 光纤通信系统. 北京:北京邮电大学出版社,1999
[45] H. Lundqvist and G. Karlsson. On Error-Correction Coding for CDMA PON. Journal of Lightwave Technology, 23(8), 2005, 2342-2351
[46] A. Srivastava, S. Kar, V.K. Jain. Forward error correcting codes in fiber-optic synchronous code-division multiple access networks, Optical Communications, v202, 2002, 287-296