WiMAX与3G融合网络的呼叫接入控制研究
摘要
WiMAX是一种新的无线城域网接入技术，能够在比Wi-Fi更广阔的地域范围内提供“最后一公里”宽带接入。为了适应QoS要求和多媒体应用，IEEE 802．16系列标准专门定义了四种不同的业务类型：主动授权、实时查询、非实时查询和尽力而为业务。虽然IEEE 802．16的MAC层协议对QoS服务流和参数配置体系、基于QoS的调度服务类别和相应的带宽请求／分配进行了定义，但是并没有定义接入控制策略、QoS参数映射、分组调度算法等问题，这些都是研究的热点问题。为了提高系统效率，满足用户间公平性，支持不同业务的QoS需求，同时考虑到WiMAX作为4G通信系统的技术之一，需要和3G等下一代网络的协同工作，我们需要研究和实现WiMAX的接入控制及其与下一代网络的融合策略问题。
本文在总结前人研究成果的基础上，对无线城域网标准IEEE 802．16系列协议进行概述，并且介绍QoS的概念和实现机制，研究了WiMAX网络中的呼叫允许控制策略，用以保证各类业务的QoS需求，提高带宽资源利用率。
首先针对WiMAX网络的特点。依据IEEE 802．16标准中提出的四种业务类型的QoS要求，提出不同业务的接入控制机制，在保证尽可能多的用户能够接入网络得到高服务质量的同时，充分兼顾不同业务的QoS要求。本文的接入控制策略，首先根据业务优先级的差别，在同时接到连接请求的时候，优先接入优先级高(实时)的连接请求。在系统资源不足的情况下，对已接入的连接降级压缩占用带宽，来保证高优先级业务的带宽要求。其次，为了保证系统的公平性，设置一定的门限来保证低优先级(非实时)业务的连接请求。这样，既保证了高优先级的业务有较高的接入成功率，同时兼顾了不同用户的QoS要求，提高了系统资源利用率，降低呼叫阻塞率。
本文的另一个重要研究内容为WiMAX和3G网络融合下的接入控制问题。随着WiMAX和3G技术的发展，网络融合是必然的趋势。WiMAX最合理的定位是为3G网络提供地域补充和热点地区回传。在融合网络基站控制下，3G网络的数据业务可以同过用户站被映射并垂直切换到WiMAX网络。所以3G网络的负载将会降低，可以接受更多的会话类业务和流类业务。仿真结果表明，通过这种策略可以降低3G网络阻塞率，提高混合网络吞吐量，并有效的保障了各类业务的QoS。最后，对全文进行了总结。
As a new access technology for Metropolitan Area Networks (MANs), WiMAX can provide the broadband access in "the last mile" for wider areas than Wi-Fi. To fulfill the requirements of QoS and multimedia applications, the IEEE 802.16 standard series define four different scheduling services: Unsolicited Grant Service (UGS), real-time Polling Service (rtPS), non-real-time Polling Service (nrtPS), and Best Effort (BE). The MAC layer of IEEE 802.16 standard specifies QoS service flows, their parameter configuration mechanisms, scheduling service types based on QoS and corresponding bandwidth request/allocation, but the standard leaves some important issues such as access control strategy, QoS parameter mapping and packet scheduling algorithms undefined. These hot problems are expected to be resolved by the researchers. For improving the system efficiency, achieving user fairness, satisfying the QoS requirements of various services, and cooperating with 3G and next generation networks as the part of 4G system, we need to research and implement the access control schemes for WiMAX.
In this thesis, in order to guarantee the QoS requirements of various services and improve the wireless resource utilization, the call admission control (CAC) policies in WiMAX networks are proposed based on existing studys.
On the one hand, according to the characteristics of WiMAX networks and the QoS requirements of the four different service types in the IEEE 802.16 family standards, the admission control mechanisms for different services are proposed, on the condition that most subscribers can access the network to get high-quality services and meanwhile the QoS requirements of different services are all considered. In the scheme of this thesis, the BS will grant the request of high priority traffic (real-time traffic) connections according to the difference of various priorities of services if it gets connection requests simultaneously. If the bandwidth is not enough for a new high priority traffic accessed, the low priority traffic will be degraded to release bandwidth for it. On the other hand, to guarantee the fairness of the system, a threshold-based scheme is used to ensure the QoS requirements of the non-real-time traffics. In this way, we gain the goals that high-priority services have higher probability of admission; the QoS requirements of different subscribers are considered, and the ratio of system resource utilization is increased and the ratio of congestion is reduced.
Another important research of this thesis is about the admission control of WiMAX and 3G convergent network. Along with the development of WiMAX and 3G, the convergent network is the trend of next generation wireless networks. The most sensible position of WiMAX is to provide area supplements and transmission from hotspots. In the control of convergent BS, the data traffic in 3G network can be mapped and vertical handed off to WiMAX network in subscriber station. So the load of 3G network will decrease and more conversational and streaming traffic requests can be accepted. The simulation results show that the block probability is reduced in 3G network, the throughput is increased in the double networks, and the QoS of different traffics can be guaranteed efficiently.
本文在总结前人研究成果的基础上，对无线城域网标准IEEE 802．16系列协议进行概述，并且介绍QoS的概念和实现机制，研究了WiMAX网络中的呼叫允许控制策略，用以保证各类业务的QoS需求，提高带宽资源利用率。
首先针对WiMAX网络的特点。依据IEEE 802．16标准中提出的四种业务类型的QoS要求，提出不同业务的接入控制机制，在保证尽可能多的用户能够接入网络得到高服务质量的同时，充分兼顾不同业务的QoS要求。本文的接入控制策略，首先根据业务优先级的差别，在同时接到连接请求的时候，优先接入优先级高(实时)的连接请求。在系统资源不足的情况下，对已接入的连接降级压缩占用带宽，来保证高优先级业务的带宽要求。其次，为了保证系统的公平性，设置一定的门限来保证低优先级(非实时)业务的连接请求。这样，既保证了高优先级的业务有较高的接入成功率，同时兼顾了不同用户的QoS要求，提高了系统资源利用率，降低呼叫阻塞率。
本文的另一个重要研究内容为WiMAX和3G网络融合下的接入控制问题。随着WiMAX和3G技术的发展，网络融合是必然的趋势。WiMAX最合理的定位是为3G网络提供地域补充和热点地区回传。在融合网络基站控制下，3G网络的数据业务可以同过用户站被映射并垂直切换到WiMAX网络。所以3G网络的负载将会降低，可以接受更多的会话类业务和流类业务。仿真结果表明，通过这种策略可以降低3G网络阻塞率，提高混合网络吞吐量，并有效的保障了各类业务的QoS。最后，对全文进行了总结。
As a new access technology for Metropolitan Area Networks (MANs), WiMAX can provide the broadband access in "the last mile" for wider areas than Wi-Fi. To fulfill the requirements of QoS and multimedia applications, the IEEE 802.16 standard series define four different scheduling services: Unsolicited Grant Service (UGS), real-time Polling Service (rtPS), non-real-time Polling Service (nrtPS), and Best Effort (BE). The MAC layer of IEEE 802.16 standard specifies QoS service flows, their parameter configuration mechanisms, scheduling service types based on QoS and corresponding bandwidth request/allocation, but the standard leaves some important issues such as access control strategy, QoS parameter mapping and packet scheduling algorithms undefined. These hot problems are expected to be resolved by the researchers. For improving the system efficiency, achieving user fairness, satisfying the QoS requirements of various services, and cooperating with 3G and next generation networks as the part of 4G system, we need to research and implement the access control schemes for WiMAX.
In this thesis, in order to guarantee the QoS requirements of various services and improve the wireless resource utilization, the call admission control (CAC) policies in WiMAX networks are proposed based on existing studys.
On the one hand, according to the characteristics of WiMAX networks and the QoS requirements of the four different service types in the IEEE 802.16 family standards, the admission control mechanisms for different services are proposed, on the condition that most subscribers can access the network to get high-quality services and meanwhile the QoS requirements of different services are all considered. In the scheme of this thesis, the BS will grant the request of high priority traffic (real-time traffic) connections according to the difference of various priorities of services if it gets connection requests simultaneously. If the bandwidth is not enough for a new high priority traffic accessed, the low priority traffic will be degraded to release bandwidth for it. On the other hand, to guarantee the fairness of the system, a threshold-based scheme is used to ensure the QoS requirements of the non-real-time traffics. In this way, we gain the goals that high-priority services have higher probability of admission; the QoS requirements of different subscribers are considered, and the ratio of system resource utilization is increased and the ratio of congestion is reduced.
Another important research of this thesis is about the admission control of WiMAX and 3G convergent network. Along with the development of WiMAX and 3G, the convergent network is the trend of next generation wireless networks. The most sensible position of WiMAX is to provide area supplements and transmission from hotspots. In the control of convergent BS, the data traffic in 3G network can be mapped and vertical handed off to WiMAX network in subscriber station. So the load of 3G network will decrease and more conversational and streaming traffic requests can be accepted. The simulation results show that the block probability is reduced in 3G network, the throughput is increased in the double networks, and the QoS of different traffics can be guaranteed efficiently.
引文
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[12]J.R.Moorman, J.W.Lockwood. Wireless call admission control using threshold access sharing. Global Telecommunications Conference, GLOBECOM'01. IEEE Volume 6,25-29 Nov.2001: 3698-3703
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[23]E.M.Crovella, A.Bestavros. Self-Similarity in World Wide Web Traffic Evidence and
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[25]石春艳．自相似网络几种不同模型的比较和分析．电信快报．2004(6)：39-41
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[27] Qi Bi,Zysman G L,Menkes H. Wireless Mobile Communications at the Start of the 21st Century.Communications Magazine,IEEE,Jan 2001-39:110-116
[28] Vijayan R, Holtzman J M. A Model for Analyzing Handoff Algorithms. Vehicular Technology, IEEE Transactions Aug 1993:351-356
[30] Neves, P.; Sargento, S.; Aguiar, R.L.,Support of Real-Time. Services over Integrated 802.16 Metropolitan and Local Area Networks Computers and Communications, 2006. ISCC '06.
[31] Mukul, R.; Singh, P.; Jayaram, D.; Das, D.; Sreenivasulu, N.; Vinay, K.; Ramamoorthy, adaptive bandwidth request mechanism for QoS enhancement in WiMax real time communication Wireless and Optical Communications Networks, 2006
[32] Vinel, A.; Ying Zhang; Lott, M.; Tiurlikov, A.,Performance Analysis of the Random Access in IEEE 802.16 Personal, Indoor and Mobile Radio Communications, 2005
[33] T. Zhang et al., Local Predictive Resource Reservation for Handoff in MultimediaWireless IP Networks, IEEE JSAC, Oct. 2001:1931-1941.
[34] Doo Hwan Lee; Kyamakya, K.; Umondi, J.P, Fast handover algorithm for IEEE 802.16e broadband wireless access system Wireless Pervasive Computing, 2006 1st International Symposium on Jan. 2006
[35] Jianfeng Chen; Wenhua Jiao; Qian Guo,An integrated QoS control architecture for IEEE 802.16 broadband wireless access systems Global Telecommunications Conference, 2005. GLOBECOM'05. IEEE
[36] Min-Seok Kang; Jaeshin Jang,Performance evaluation of IEEE 802.16d ARQ algorithms with NS-2 simulator Communications, 2006 Asia-Pacific Conference
[37] M. Settembre, M. Puleri, S. Garritano&, P. Testa, R. Albanese, M. Mancini, V. Lo Curto,Performance Analysis of An Efficient Packet-Based IEEE 802.16 MAC Supporting Adaptive Modulation and Coding,Proceedings of the Seventh IEEE International Symposium on Computer Networks (ISCN' 06)
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[39] J.R.Moorman, J.W.Lockwood. Wireless call admission control using threshold access sharing. Global Telecommunications Conference, GLOBECOM 'O1. IEEE Volume 6,25-29 Nov. 2001
[40]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
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[2]Marks, R.B The IEEE 802.16 Working Group on broadband wireless Network, IEEEVolume 13, Issue 2, March-April 1999:301-312
[3]A. Paolo,C.Massimo and S.Marco, Broadband wireless access: International standardization and marked trend, AIIT Telecommunication Conference,2000.
[4]White Paper, IEEE 802.16 and WiMAX - Broadband Wireless Access for Everyone,www.Intel.com
[5]C.Eklund, Roger Marks,Kenneth Stanwood and Stanley Wang, IEEE Standard 802.16: A technical overview of the WirelessMAN Air Interface for broadband wireless access, IEEE Communication Magazine ,June 2002:98-106
[6]L. Badia, M. Zorzi, and A. Gazzini, A Model for Threshold Comparison Call Admission Control in Third Generation Cellular Systems, Proc. IEEE ICC'03, vol. 3, May 2003: 1664-68.
[7]T. Zhang et al., Local Predictive Resource Reservation for Handoff in Multimedia Wireless IP Networks, IEEE JSAC, vol. 19, no. 10, Oct. 2001:1931-41.
[8]R. Jain and E. W. Knightly, A Framework for Design and Evaluation of Admission Control Algorithms in Multi-Service Mobile Networks, Proc. IEEE INFOCOM '99, Mar. 1999:1027-35.
[9]王兵，张智江，李正茂，WiMAX系统及其QoS机制研究，中兴通讯技术，2006年8月第12卷第4期
[10]Jianfeng Chen, Wenhua jiao, Qian Guo. Providing Integrated QoS Control for IEEE 802.16 Broadband Wireless Access Systems.
[11]Haitang Wang, Wei Li and Dharma P.Agrawal, Dynamic Admission Control and QoS for 802.16 Wireless MAN, 2005 Wireless Telecommunications Symposium, April 2005.
[12]J.R.Moorman, J.W.Lockwood. Wireless call admission control using threshold access sharing. Global Telecommunications Conference, GLOBECOM'01. IEEE Volume 6,25-29 Nov.2001: 3698-3703
[13]Howon Lee; Taesoo Kwon; Dong-Ho Cho; Geunhwi Lim; Yong Chang, Performance Analysis of Scheduling Algorithms for VoIP Services in IEEE 802.16e Systems Vehicular Technology Conference, 2006. VTC 2006-Spring. IEEE 63rd 2006
[14]Settembre, M.; Puleri, M.; Garritano, S.; Testa, P.; Albanese, R.; Mancini, M.; Lo Curto, V.,Performanee analysis of an efficient packet-based IEEE 802.16 MAC supporting adaptive modulation and coding Computer Networks, 2006 International Symposium June 2006
[15]Tomasin, S.; Benvenuto, N.,Performance comparison of frequency domain equalizers for the IEEE 802.16a WMAN standard Information and Communication Technologies: From Theory to Applications, 2004. Proceedings. 2004 International Conference
[16]Yanling Yao; Sun, J., Study of UGS grant synchronization for 802.16 Consumer Electronics,2005. (ISCE 2005).
[17]GuoSong Chu; Deng Wang; Shunliang Mei,A QoS architecture for the. MAC protocol of IEEE 802.16 BWA system Communications, Circuits and Systems and West Sino Expositions,IEEE 2002 International Conference 29 June-1 July 2002
[18]Koffman, I.; Roman, V.,Broadband wireless access solutions based on OFDM access in IEEE 802.16 Communications Magazine, IEEE April 2002
[19]杨峰义，覃燕敏，胡强．WCDMA无线网络工程．人民邮电出版社。2004
[20](芬)哈里·霍尔马．安提·托斯卡拉．WCDMA技术与系统设计．机械工业出版社．2002．1
[21]F.Y.Li, N.Stol. A Priority-oriented call admission control paradigm with QoS re-negotiation for multimedia services in UMTS. IEEE VTS 53rd Vehicular Technology Conference. 2001,vol.3:2021-2025
[22]3rd Generation Partnership Project, QoS Concept and Architecture, TS 23.107 V5.4.0,2002.3
[23]E.M.Crovella, A.Bestavros. Self-Similarity in World Wide Web Traffic Evidence and
Possible Causes. 1996 ACM Conference on Measurement and Modeling of Computer Systems.Philadelphia, PA, 1996.5
[24]胡严，张光昭．重尾ON/OFF源模型生成自相似业务流研究．电路与系统学报．2001，6(3)：72-76
[25]石春艳．自相似网络几种不同模型的比较和分析．电信快报．2004(6)：39-41
[26]许都，李乐民．长相关业务流经成形器后的输出特性研究．电路与系统学报．1998．3(1)： 66-70
[27] Qi Bi,Zysman G L,Menkes H. Wireless Mobile Communications at the Start of the 21st Century.Communications Magazine,IEEE,Jan 2001-39:110-116
[28] Vijayan R, Holtzman J M. A Model for Analyzing Handoff Algorithms. Vehicular Technology, IEEE Transactions Aug 1993:351-356
[30] Neves, P.; Sargento, S.; Aguiar, R.L.,Support of Real-Time. Services over Integrated 802.16 Metropolitan and Local Area Networks Computers and Communications, 2006. ISCC '06.
[31] Mukul, R.; Singh, P.; Jayaram, D.; Das, D.; Sreenivasulu, N.; Vinay, K.; Ramamoorthy, adaptive bandwidth request mechanism for QoS enhancement in WiMax real time communication Wireless and Optical Communications Networks, 2006
[32] Vinel, A.; Ying Zhang; Lott, M.; Tiurlikov, A.,Performance Analysis of the Random Access in IEEE 802.16 Personal, Indoor and Mobile Radio Communications, 2005
[33] T. Zhang et al., Local Predictive Resource Reservation for Handoff in MultimediaWireless IP Networks, IEEE JSAC, Oct. 2001:1931-1941.
[34] Doo Hwan Lee; Kyamakya, K.; Umondi, J.P, Fast handover algorithm for IEEE 802.16e broadband wireless access system Wireless Pervasive Computing, 2006 1st International Symposium on Jan. 2006
[35] Jianfeng Chen; Wenhua Jiao; Qian Guo,An integrated QoS control architecture for IEEE 802.16 broadband wireless access systems Global Telecommunications Conference, 2005. GLOBECOM'05. IEEE
[36] Min-Seok Kang; Jaeshin Jang,Performance evaluation of IEEE 802.16d ARQ algorithms with NS-2 simulator Communications, 2006 Asia-Pacific Conference
[37] M. Settembre, M. Puleri, S. Garritano&, P. Testa, R. Albanese, M. Mancini, V. Lo Curto,Performance Analysis of An Efficient Packet-Based IEEE 802.16 MAC Supporting Adaptive Modulation and Coding,Proceedings of the Seventh IEEE International Symposium on Computer Networks (ISCN' 06)
[38] 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
[39] J.R.Moorman, J.W.Lockwood. Wireless call admission control using threshold access sharing. Global Telecommunications Conference, GLOBECOM 'O1. IEEE Volume 6,25-29 Nov. 2001
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