宽带无线接入系统仿真与评估关键技术研究
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摘要
随着人们对于互联网需求的日益增长,通信的移动化和宽带化是必然的发展趋势,作为“最后一公里”的宽带无线接入技术有广泛的应用前景,以IEEE802.16e标准为基础的WiMAX技术已经成为宽带无线技术的主流。WiMAX作为一种面向无线城域网(WMAN)的宽带接入方案,以其优异的性能和广阔的市场前景而倍受关注,已经得到了很多运营商的认可。
WiMAX系统的网络质量、覆盖、容量之间有着非常复杂的动态关系,加上多种类型业务的引入,因此,很难简单地从理论上准确地对系统整体性能进行分析。目前,使用软件仿真技术进行移动通信协议研究、网络规划、性能评估和优化已经成为了一种基本手段。
本文的工作分为系统仿真平台设计实现和系统性能评估两个方面。通过对无线通信系统仿真模型的研究,结合IEEE 802.16e协议,基于OPNET网络仿真软件,设计和开发了WiMAX系统级仿真平台。详细阐述了无线资源调度器和无线信道模拟的实现。而且对小区覆盖、不同子载波排列方式的扇区吞吐量以及混合自动重传(HARQ)进行了系统性能仿真评估。本文最后针对一种具体的实时业务,比较分析了协议规定的三种实时调度机制,并在具体实现中提出了改进方案。系统仿真结果表明,改进的方案减小了用户的上行接入时延,提高了通信质量。
With the growing demand for the Internet Network, the mobilization and broadband is the inevitable development trends of future communication systems. Broadband Access Technologies has a wide application prospect as the last-mile technologies. WiMAX based on IEEE 802.16e has become a major technology for broadband access. As a broadband access scheme for Wireless Metropolitan Area Networks (WMAN), WiMAX has received much attention for its outstanding performance and wide market prospects, and has been approbated by many network operators.
The dynamic relationship among quality, coverage, capacity of WiMAX network is very complicated. In addition, many kinds of services are being introduced into the WiMAX network. As a result, it is difficult to analyze the whole performance of the system accurately in theory. Nowadays, software simulation technique has become a popular basic method for mobile communication protocol research, network planning, performance evaluation and optimization.
The work of this dissertation could be divided into two parts, one part is the design and implementation of system level simulation platform, and the other part is system performance evaluation. Through the research of simulation models for wireless communication system, combined with the IEEE 802.16e protocol, we designed and developed system level simulation platform for WiMAX system based on OPNET network simulation software. This paper addressed the implementation of radio resource scheduler and radio channel simulation in detail. Moreover, we made system performance simulation for cell coverage, sector throughput under different subcarrier permutation, and hybrid automatic repeat request(HARQ). At the last section, we analyzed and compared the three real-time scheduling schemes specified in the protocol when they were used for a specific type of real-time service, and proposed an improved scheduling scheme. System level simulations show that the proposed scheme reduced the user's uplink access delay, and consequently improved the communication quality.
WiMAX系统的网络质量、覆盖、容量之间有着非常复杂的动态关系,加上多种类型业务的引入,因此,很难简单地从理论上准确地对系统整体性能进行分析。目前,使用软件仿真技术进行移动通信协议研究、网络规划、性能评估和优化已经成为了一种基本手段。
本文的工作分为系统仿真平台设计实现和系统性能评估两个方面。通过对无线通信系统仿真模型的研究,结合IEEE 802.16e协议,基于OPNET网络仿真软件,设计和开发了WiMAX系统级仿真平台。详细阐述了无线资源调度器和无线信道模拟的实现。而且对小区覆盖、不同子载波排列方式的扇区吞吐量以及混合自动重传(HARQ)进行了系统性能仿真评估。本文最后针对一种具体的实时业务,比较分析了协议规定的三种实时调度机制,并在具体实现中提出了改进方案。系统仿真结果表明,改进的方案减小了用户的上行接入时延,提高了通信质量。
With the growing demand for the Internet Network, the mobilization and broadband is the inevitable development trends of future communication systems. Broadband Access Technologies has a wide application prospect as the last-mile technologies. WiMAX based on IEEE 802.16e has become a major technology for broadband access. As a broadband access scheme for Wireless Metropolitan Area Networks (WMAN), WiMAX has received much attention for its outstanding performance and wide market prospects, and has been approbated by many network operators.
The dynamic relationship among quality, coverage, capacity of WiMAX network is very complicated. In addition, many kinds of services are being introduced into the WiMAX network. As a result, it is difficult to analyze the whole performance of the system accurately in theory. Nowadays, software simulation technique has become a popular basic method for mobile communication protocol research, network planning, performance evaluation and optimization.
The work of this dissertation could be divided into two parts, one part is the design and implementation of system level simulation platform, and the other part is system performance evaluation. Through the research of simulation models for wireless communication system, combined with the IEEE 802.16e protocol, we designed and developed system level simulation platform for WiMAX system based on OPNET network simulation software. This paper addressed the implementation of radio resource scheduler and radio channel simulation in detail. Moreover, we made system performance simulation for cell coverage, sector throughput under different subcarrier permutation, and hybrid automatic repeat request(HARQ). At the last section, we analyzed and compared the three real-time scheduling schemes specified in the protocol when they were used for a specific type of real-time service, and proposed an improved scheduling scheme. System level simulations show that the proposed scheme reduced the user's uplink access delay, and consequently improved the communication quality.
引文
[1]3GPP2,cdma2000 Evaluation Methodology,Revision 0,December 10,2004.
[2]IEEE.IEEE Standard for Local and Metropolitan Area Networks-Part 16:Air Interface for Fixed and Mobile Broadband Wireless Access System.IEEE Std802.16e-2005.
[3]孙黎辉.3G无线网络系统级仿真与网络规划.移动通信,2006.8:51-54.
[4]WiMAX Forum.WiMAX System Evaluation Methodology,Version 2.0.December 15,2007.
[5]Xin Chang,Juejun Liu,Jianmin Lu,Zhigang Rong,Xiaolu Dong.System Evaluation Methodology for VoIP Service,IEEE C802.16m-07/067.
[6]马楠,王莹,张平等.基于OPNET的移动WiMAX网络仿真.计算机系统应用,2006年第12期:47-50.
[7]3GPP TSG-RANl#48 R1-070674.LTE physical layer framework for performance verification.Orange,China Mobile,KPN,NTT,DoCcMo,Sprint,T-Mobile,Vodafone,Telecom Italia,February 2007.
[8]3GPP TSG-RAN-1,Nortel Networks,"Modelling of Performance with Coloured Interference Using the EESM(Exponential Effective SIR Mapping)",Document R1-04-0509,Meeting #37,Montreal,Quebec,Canada,May10-14/2004.
[9]S.Tiraspolsky,A.Rubtsov,A.Maltsev,A.Davydov.Mobile WiMAX-Deployment Scenarios Performance Analysis,2006.ISWCS'06.3~(rd)International Symposium on Wireless Communication Systems,6-8 Sept.2006 Page(s):353-357.
[10]Severine Catreux,Vinko Erceg,David Gesbert,Robert W.Heath.Adaptive Modulation and MIMO Coding for Broadband Wireless Data Networks,IEEE Communications Magazine,June 2002 Page(s):108-115.
[11]Yuval Lomnitz,Tom Harel.A comment on Phy-abstraction of H-ARQ,IEEE C802.16m-07/194,2007-09-18.
[12]George Calcev,Chizhik D,Goransson B,Howard S,Huang H,Kogiantis A,Molisch,A.F,Moustakas A.L,Reed,D,Hao Xu.A Wideband Spatial Channel Model for System-Wide Simulations,Vehicular Technology,IEEE Transactions on Volume 56,Issue 2,March 2007 Page(s):389-403.
[13]3GPP TR 25.996,Spatial channel model for Multiple Input Multiple Output(MIMO)Simulations,Sept.,2003.
[14]V.Erceg,K.V.S.Hari,M.S.Smith,Channel Models for Fixed Wireless Applications,IEEE 802.16.3 c-01/29r4.
[15]P.Almers,E.Bonek,A.Burr,N.Czink,M.Debbah,etc,Survey of Channel and Radio Propagation Models for Wireless MIMO Systems,EURASIP Journal on Wireless Communications and Networking Volume 2007 Page(s):1-19.
[16]J.D.Parsons.The Mobile Radio Propagation Channel,2~(nd)Edition,Wiley;2edition(November 29,2000).
[17]T-S Chu,L.J.Greenstein.A quantification of link budget differences between the cellular and PCS bands,IEEE Trans VT-48,NO.1,January 1999,Page(s):60-65.
[18]W.C.Jakes and D.O.Reudink.Comparison of mobile radio transmission at UHF and X-band.IEEE Trans.Veh.Technol,vol.VT-16,pp.10-13,Oct.1967.
[19]Narandzic,M.,Schneider,C.,Thoma,R.,Jamsa,T.;Kyosti,P.;Xiongwen Zhao;Comparison of SCM,SCME,and WINNER Channel Models,Vehicular Technology Conference,2007.VTC2007-Spring.IEEE 65~(th)22-25 April 2007 Page(s):413-417.
[20]Ken J.Kerpez,A Radio Access System With Distributed Antennas.IEEE Transaction on Vehicular Technology,VOL.45,NO.2,May 1996,265-274.
[21]孙程君,张中兆,巴勇,曹鹏志.移动通信系统系统级仿真中慢衰落相关性的研究,通信学报,2002年8月,第23卷第8期:33-39.
[22]无线通信原理与应用(第二版)/(美)拉帕波特著;周文安等译.北京:电子工业出版社,2006.7.
[23]IEEE 802.16 Broadband Wireless Access Working Group,Project 802.16m Evaluation Methodology Document(EMD),2008-03-04,IEEE 802.16m-08/004.
[24]Daniel Sweeney.WiMax Operator's Manual-Building 802.16 Wireless Networks,Second Edition.
[25]WiMAX Forum.A Comparative Analysis of Mobile WiMAXTM Deployment Alternatives in the Access Network,May 2007.
[26]Dorleus Joseph,Holweck Ralph,Ren Zhi,Li Hongbin,Cui Hong-Liang,Medina John.Modeling and Simulation of Fading and Pathloss in OPNET for Range Communications.Radio and Wireless Symposium,2007 IEEE 9-11 Jan.2007Page(s):407-410.
[27]Monica Pallini,Senza Fili Consultion.Building End-to-End WiMAX Networks.WiMAX White Paper,April 2007.
[28]Tsz Ho Chan,Chui Ying Cheung,Mounir Hamdi,Maode Ma.Overview of rate adaptation algorithms based on MIMO technology in WiMAX networks.Mobile WiMAX Symposium,2007.IEEE Volume,Issue,25-29 March 2007 Page(s):98-103.
[29]赵琼,王衍文.WiMAX系统中的多天线技术及应用.中兴通讯技术,2007年13卷2期:28-31.
[30]Huijie Li,Xiaokang Lin.An OPNET-based 3-tier network simulation architecture.IEEE International Symposium on Communications and Information Technology '05,pp.793-76,October 2005.
[31]Louay M.A.Jalloul and Sam P.Alex.SINR Computations,Presented to IEEE Communications & Signal Processing Societies Orange County Joint Chapter(ComSig),December 7,2006.
[32]Tsz Ho Chan,Chui Ying Cheung,Mounir Hamdi,Maode Ma,Overview of rate adaptation algorithms based on MIMO technology in WiMAX networks,Mobile WiMAX Symposium,2007.IEEE,25-29 March 2007 Page(s):98-103.
[33]Siavash M.Alamouti.Mobile Broadband:Vision & Evolution,Intel.
[34]Jianfeng Chen,Wenhua Jiao,Hongxi Wang.A service flow management strategy for IEEE 802.16 broadband wireless access systems in TDD mode,ICC.2005,Page(s):3422-3426 Vol.5.
[35]Berggren,F.Jantti,R.Multiuser scheduling over Rayleigh fading channels.Global Telecommunications Conference,2003.GLOBECOM'03.IEEE,158-162 Vol.1.
[36]WiMAX Forum.Mobile WiMAX-Part 1:A Technical Overview and Performance Evaluation,August,2006.
[37]Claudio Cicconetti,Alessandro Erta,Luciano Lenzini,and Enzo Mingozzi.Performance Evaluation of the IEEE 802.16 MAC for QoS Support,IEEE Transactions on Mobile Computing,vol.6,NO.1,January 2007.
[38]Qualcomm Europe,Reference Node-B scheduler for EUL,R1-031246,3GPP TSG-RAN 1 #35,November 17-21,2003.
[39]K.Wongthavarawat,and A.Ganz.Packet Scheduling for QoS Support in IEEE 802.16broadband wireless access systems,International Journal of Communication Systems,2003;16,Page(s):81-96.
[40]Ameigeiras,P,Wigard,J,Mogensen,P.Performance of the M-LWDF scheduling algorithm for streaming services in HSDPA,IEEE VTC2004-Fall,Vol.2,Page(s):999-1003.
[41]Motorola,EESM Link Error Prediction for EUTRA System Evaluation,3GPP TSG RAN WGl#42,London,U.K,Aug 29-Sept 2,2005,R1-050718.
[42]Erik Westman,Calibration and evaluatin of the Exponential Effective SINR Mapping (EESM)in 802.16,September 7,2006.
[43]韦惠民,李白萍,蜂窝移动通信技术—西安:西安电子科技大学出版社,2002.8.
[44]Gerrit Hiddink,Joe Schumacher.Confirmation of resuming periodic allocations after ertPS silence suppression,IEEE 802.16 Broadband Wireless Access Working Group,2007-11-04.
[45]Howon Lee,Taesoo Kwon,Kong-Ho Cho,An Enhanced Uplink Scheduling Algorithm Based on Voice Activity for VolP Services in IEEE 802.16d/e System,IEEE Communications Letters,Aug2005,Page(s):691-693.
[46]Howon Lee,Taesoo Kwon,Kong-Ho Cho,etc,Performance Analysis of Scheduling Algorithms for VolP Services in IEEE 802.16e Systems,Vehicular Technology Conference,2006.VTC 2006-Spring.IEEE 63~(rd),Page(s):1231-1235.
[47]董国军,戴居丰.IEEE802.16e的实时上行链路调度服务优化算法.计算机应用,2007年6月,第27卷第6期:1310-1313.
[48]张瀚峰,杨斌,吴伟陵.宽带无线多播轮询VoIP业务上行调度机制.北京邮电大学学报,2007年4月,第30卷第2期:28-31.
[49]Shamik Sengupta,Mainak Chatterjee,Samrat Ganguly,Improving Quality of VoIP Streams over WiMax,IEEE Transactions on Computers,Vol.57,NO.2,February 2008 Page(s):145-156.
[50]Jeonghoon Mo,Evaluation of Maximum Number of VolP Calls over WiMAX Networks with WiBro Profile-Version 2.0,VolP White Paper,WiMAX Forum,March 2,2007.
[51]陈敏.OPNET网络仿真.北京:清华大学出版社,2004.
[52]李建东.信息网络理论基础.西安:西安电子科技大学出版社,2001.
[53]QUALCOMM Europe,3GPP R1-050896,Description and simulations of interference management technique for OFDMA based E-UTRA downlink evaluation,2005.
[54]Huawei,3GPP R1-050507,Soft Frequency Reuse Scheme for UTRAN LTE,2005.
[55]Huawei,3GPP R1-050841,Further analysis of soft frequency reuse scheme,2005.
[2]IEEE.IEEE Standard for Local and Metropolitan Area Networks-Part 16:Air Interface for Fixed and Mobile Broadband Wireless Access System.IEEE Std802.16e-2005.
[3]孙黎辉.3G无线网络系统级仿真与网络规划.移动通信,2006.8:51-54.
[4]WiMAX Forum.WiMAX System Evaluation Methodology,Version 2.0.December 15,2007.
[5]Xin Chang,Juejun Liu,Jianmin Lu,Zhigang Rong,Xiaolu Dong.System Evaluation Methodology for VoIP Service,IEEE C802.16m-07/067.
[6]马楠,王莹,张平等.基于OPNET的移动WiMAX网络仿真.计算机系统应用,2006年第12期:47-50.
[7]3GPP TSG-RANl#48 R1-070674.LTE physical layer framework for performance verification.Orange,China Mobile,KPN,NTT,DoCcMo,Sprint,T-Mobile,Vodafone,Telecom Italia,February 2007.
[8]3GPP TSG-RAN-1,Nortel Networks,"Modelling of Performance with Coloured Interference Using the EESM(Exponential Effective SIR Mapping)",Document R1-04-0509,Meeting #37,Montreal,Quebec,Canada,May10-14/2004.
[9]S.Tiraspolsky,A.Rubtsov,A.Maltsev,A.Davydov.Mobile WiMAX-Deployment Scenarios Performance Analysis,2006.ISWCS'06.3~(rd)International Symposium on Wireless Communication Systems,6-8 Sept.2006 Page(s):353-357.
[10]Severine Catreux,Vinko Erceg,David Gesbert,Robert W.Heath.Adaptive Modulation and MIMO Coding for Broadband Wireless Data Networks,IEEE Communications Magazine,June 2002 Page(s):108-115.
[11]Yuval Lomnitz,Tom Harel.A comment on Phy-abstraction of H-ARQ,IEEE C802.16m-07/194,2007-09-18.
[12]George Calcev,Chizhik D,Goransson B,Howard S,Huang H,Kogiantis A,Molisch,A.F,Moustakas A.L,Reed,D,Hao Xu.A Wideband Spatial Channel Model for System-Wide Simulations,Vehicular Technology,IEEE Transactions on Volume 56,Issue 2,March 2007 Page(s):389-403.
[13]3GPP TR 25.996,Spatial channel model for Multiple Input Multiple Output(MIMO)Simulations,Sept.,2003.
[14]V.Erceg,K.V.S.Hari,M.S.Smith,Channel Models for Fixed Wireless Applications,IEEE 802.16.3 c-01/29r4.
[15]P.Almers,E.Bonek,A.Burr,N.Czink,M.Debbah,etc,Survey of Channel and Radio Propagation Models for Wireless MIMO Systems,EURASIP Journal on Wireless Communications and Networking Volume 2007 Page(s):1-19.
[16]J.D.Parsons.The Mobile Radio Propagation Channel,2~(nd)Edition,Wiley;2edition(November 29,2000).
[17]T-S Chu,L.J.Greenstein.A quantification of link budget differences between the cellular and PCS bands,IEEE Trans VT-48,NO.1,January 1999,Page(s):60-65.
[18]W.C.Jakes and D.O.Reudink.Comparison of mobile radio transmission at UHF and X-band.IEEE Trans.Veh.Technol,vol.VT-16,pp.10-13,Oct.1967.
[19]Narandzic,M.,Schneider,C.,Thoma,R.,Jamsa,T.;Kyosti,P.;Xiongwen Zhao;Comparison of SCM,SCME,and WINNER Channel Models,Vehicular Technology Conference,2007.VTC2007-Spring.IEEE 65~(th)22-25 April 2007 Page(s):413-417.
[20]Ken J.Kerpez,A Radio Access System With Distributed Antennas.IEEE Transaction on Vehicular Technology,VOL.45,NO.2,May 1996,265-274.
[21]孙程君,张中兆,巴勇,曹鹏志.移动通信系统系统级仿真中慢衰落相关性的研究,通信学报,2002年8月,第23卷第8期:33-39.
[22]无线通信原理与应用(第二版)/(美)拉帕波特著;周文安等译.北京:电子工业出版社,2006.7.
[23]IEEE 802.16 Broadband Wireless Access Working Group,Project 802.16m Evaluation Methodology Document(EMD),2008-03-04,IEEE 802.16m-08/004.
[24]Daniel Sweeney.WiMax Operator's Manual-Building 802.16 Wireless Networks,Second Edition.
[25]WiMAX Forum.A Comparative Analysis of Mobile WiMAXTM Deployment Alternatives in the Access Network,May 2007.
[26]Dorleus Joseph,Holweck Ralph,Ren Zhi,Li Hongbin,Cui Hong-Liang,Medina John.Modeling and Simulation of Fading and Pathloss in OPNET for Range Communications.Radio and Wireless Symposium,2007 IEEE 9-11 Jan.2007Page(s):407-410.
[27]Monica Pallini,Senza Fili Consultion.Building End-to-End WiMAX Networks.WiMAX White Paper,April 2007.
[28]Tsz Ho Chan,Chui Ying Cheung,Mounir Hamdi,Maode Ma.Overview of rate adaptation algorithms based on MIMO technology in WiMAX networks.Mobile WiMAX Symposium,2007.IEEE Volume,Issue,25-29 March 2007 Page(s):98-103.
[29]赵琼,王衍文.WiMAX系统中的多天线技术及应用.中兴通讯技术,2007年13卷2期:28-31.
[30]Huijie Li,Xiaokang Lin.An OPNET-based 3-tier network simulation architecture.IEEE International Symposium on Communications and Information Technology '05,pp.793-76,October 2005.
[31]Louay M.A.Jalloul and Sam P.Alex.SINR Computations,Presented to IEEE Communications & Signal Processing Societies Orange County Joint Chapter(ComSig),December 7,2006.
[32]Tsz Ho Chan,Chui Ying Cheung,Mounir Hamdi,Maode Ma,Overview of rate adaptation algorithms based on MIMO technology in WiMAX networks,Mobile WiMAX Symposium,2007.IEEE,25-29 March 2007 Page(s):98-103.
[33]Siavash M.Alamouti.Mobile Broadband:Vision & Evolution,Intel.
[34]Jianfeng Chen,Wenhua Jiao,Hongxi Wang.A service flow management strategy for IEEE 802.16 broadband wireless access systems in TDD mode,ICC.2005,Page(s):3422-3426 Vol.5.
[35]Berggren,F.Jantti,R.Multiuser scheduling over Rayleigh fading channels.Global Telecommunications Conference,2003.GLOBECOM'03.IEEE,158-162 Vol.1.
[36]WiMAX Forum.Mobile WiMAX-Part 1:A Technical Overview and Performance Evaluation,August,2006.
[37]Claudio Cicconetti,Alessandro Erta,Luciano Lenzini,and Enzo Mingozzi.Performance Evaluation of the IEEE 802.16 MAC for QoS Support,IEEE Transactions on Mobile Computing,vol.6,NO.1,January 2007.
[38]Qualcomm Europe,Reference Node-B scheduler for EUL,R1-031246,3GPP TSG-RAN 1 #35,November 17-21,2003.
[39]K.Wongthavarawat,and A.Ganz.Packet Scheduling for QoS Support in IEEE 802.16broadband wireless access systems,International Journal of Communication Systems,2003;16,Page(s):81-96.
[40]Ameigeiras,P,Wigard,J,Mogensen,P.Performance of the M-LWDF scheduling algorithm for streaming services in HSDPA,IEEE VTC2004-Fall,Vol.2,Page(s):999-1003.
[41]Motorola,EESM Link Error Prediction for EUTRA System Evaluation,3GPP TSG RAN WGl#42,London,U.K,Aug 29-Sept 2,2005,R1-050718.
[42]Erik Westman,Calibration and evaluatin of the Exponential Effective SINR Mapping (EESM)in 802.16,September 7,2006.
[43]韦惠民,李白萍,蜂窝移动通信技术—西安:西安电子科技大学出版社,2002.8.
[44]Gerrit Hiddink,Joe Schumacher.Confirmation of resuming periodic allocations after ertPS silence suppression,IEEE 802.16 Broadband Wireless Access Working Group,2007-11-04.
[45]Howon Lee,Taesoo Kwon,Kong-Ho Cho,An Enhanced Uplink Scheduling Algorithm Based on Voice Activity for VolP Services in IEEE 802.16d/e System,IEEE Communications Letters,Aug2005,Page(s):691-693.
[46]Howon Lee,Taesoo Kwon,Kong-Ho Cho,etc,Performance Analysis of Scheduling Algorithms for VolP Services in IEEE 802.16e Systems,Vehicular Technology Conference,2006.VTC 2006-Spring.IEEE 63~(rd),Page(s):1231-1235.
[47]董国军,戴居丰.IEEE802.16e的实时上行链路调度服务优化算法.计算机应用,2007年6月,第27卷第6期:1310-1313.
[48]张瀚峰,杨斌,吴伟陵.宽带无线多播轮询VoIP业务上行调度机制.北京邮电大学学报,2007年4月,第30卷第2期:28-31.
[49]Shamik Sengupta,Mainak Chatterjee,Samrat Ganguly,Improving Quality of VoIP Streams over WiMax,IEEE Transactions on Computers,Vol.57,NO.2,February 2008 Page(s):145-156.
[50]Jeonghoon Mo,Evaluation of Maximum Number of VolP Calls over WiMAX Networks with WiBro Profile-Version 2.0,VolP White Paper,WiMAX Forum,March 2,2007.
[51]陈敏.OPNET网络仿真.北京:清华大学出版社,2004.
[52]李建东.信息网络理论基础.西安:西安电子科技大学出版社,2001.
[53]QUALCOMM Europe,3GPP R1-050896,Description and simulations of interference management technique for OFDMA based E-UTRA downlink evaluation,2005.
[54]Huawei,3GPP R1-050507,Soft Frequency Reuse Scheme for UTRAN LTE,2005.
[55]Huawei,3GPP R1-050841,Further analysis of soft frequency reuse scheme,2005.