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无线局域网(WLAN)技术的发展带来的多媒体业务流量的剧增,是无线网络的资源管理、服务质量(QoS)保障等问题日益突出,传统的媒体访问控制(MAC)协议需要重新设计才能对无线网络的QoS问题进行有效的解决。本文介绍了无限局域网QoS技术的发展,包括针对IEEE802.11MAC层协议进行的各种QoS增强技术。通过与传统的802.11标准的MAC层进行对比分析,讨论了IEEE802.11e的两个新的策略:增强的分布式协调功能和混合协调功能。通过对受控竞争机制的分析,指出了IEEE802.11e仍存在的不足及未来的发展方向。 相似文献
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无线局域网QoS机制解析 总被引:1,自引:0,他引:1
无线局域网(WLAN)技术的发展带来的多媒体业务流量的剧增,使无线网络的资源管理、服务质量(QoS)保障等问题日益突出,传统的媒体访问控制(MAC)协议需要重新设计才能有效地解决无线网络的QoS问题。本文介绍了无限局域网QoS技术的发展,包括针对IEEE802.11 MAC层协议进行的各种QoS增强技术。通过与传统的802.11标准的MAC层进行对比分析.讨论了IEEE802.11e的2个新策略:增强的分布式协调功能和混合协调功能。通过对受控竞争机制的分析,指出了IEEE802.11e仍存在的不足及未来的发展方向。 相似文献
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无线个域网(WPAN)是一种与无线广域网(WWAN)、无线城域网(WMAN)、无线局域网(WLAN)并列但覆盖范围相对较小的无线网络.WPAN所覆盖的范围一般在10m半径以内,必须运行于许可的无线频段.WPAN能够有效地解决"最后的几米电缆"的问题,进而将无线联网进行到底.阐述了无线个域网基本概念、网络分类及特点,并将其与无线局域网进行简单比较,同时对相关技术进行了分析. 相似文献
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本文介绍了在无线局域网(WLAN)的MAC层CSMA/CA机制下,展开实时视、音频业务时将面临的服务质量(QoS)的相关问题,针对目前基于IEEE802.11协议的WLAN中QoS保证的主要参数、各种优化算法和方案进行分类讨论,并对未来WlAN中的QoS的研究方向作出了展望。 相似文献
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伴随2.45GHz ISM频段上无线局域网(WLAN)和无线个人局域网(WPAN)技术发展而来的是共存问题,该文在介绍了WLAN和WPAN技术的发展进程之后,探讨了以IEEE 802.11b和蓝牙为代表的WLAN和WPAN之间的共存问题及当前已提出的解决方案。 相似文献
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伴随2.45CHz ISM频段上无线局域网(WLAN)和无线个人局域网(WPAN)技术发展而来的是共存问题,该文在介绍了WLAN和WPAN技术的发展进程之后,探讨了以IEEE 802.11b和蓝牙为代表的WLAN和WPAN之间的共存问题及当前已提出的解决方案。 相似文献
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Providing end-to-end parameterized QoS is desirable for many network applications and has received a lot of attention in recent years. However, it remains a challenge, especially over hybrid networks involving both wired networks and wireless access segments (such as IEEE 802.11 Wireless Local Area Networks (WLANs)). The difficulty in achieving such QoS arises mainly because wireless segments often constitute “gaps" in terms of resource guarantee, due to the lack of efficient resource scheduling and management ability over shared wireless media, as well as the lack of an appropriate QoS signaling interface to seamlessly embed these wireless segments into an end-to-end QoS signaling system. In this paper, we consider the scenario where an IEEE 802.11 wireless node wishes to make an end-to-end resource reservation to a remote wired Internet node and vice versa. We propose Wireless Subnet Bandwidth Manager (Wireless SBM), an extension of SBM protocol to WLANs, to provide seamless end-to-end resource reservations. Wireless SBM utilizes the enhanced resource management ability provided by Hybrid Coordination Function (introduced in the upcoming IEEE 802.11e standard) to provide parameterized resource reservation and admission control. 相似文献
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无线Mesh网络与IEEE802系列标准 总被引:1,自引:0,他引:1
无线宽带接入系统发展迅速,但带宽容量低、覆盖范围小等缺点限制了它的进一步发展。作为“最后一公里”宽带无线接入非常重要的技术之一。无线Mesh网络(WMN)可以和多种无线网络系统,如无线局域网(WLAN)、无线个域网(WPAN)以及无线城域网(WMAN)等相结合,改善无线网络的性能,提高网络的覆盖范围。随着无线Mesh网络技术的厂泛应用,IEEE802的相关标准组正在致力于推动WMN技术的发展,制订相关的技术标准。目前,WMN标准已经出现在IEEE802.11s、80215、802.16、802.20中。 相似文献
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IEEE 802.15.4 (for low-rate Wireless Personal Area Networks??WPANs) (IEEE 802.15.4 Standard-2003) and IEEE 802.15.7 (for Short-Range Wireless Optical Communication Using Visible Light) (IEEE 802.15.7 Standard??2011) are two typical standards for WPANs that support Quality-of-Service (QoS) through a Guaranteed Time Slot (GTS) mechanism to allocate a specific duration within a superframe structure for a time division multiplexing transmission. The low bandwidth utilization problem may occur in the GTS mechanism when the allocated bandwidth is less than the available bandwidth. However, this problem has not been resolved thoroughly in any of the standard or current research thus far. This paper analyzes GTS performance in QoS-guaranteed transmission and proposes a new GTS allocation scheme named Unbalanced GTS Allocation Scheme (UGAS), which improves the bandwidth resource efficiency. Our scheme tries to solve the bandwidth under-utilization problem by using Network Calculus theory based on the fluid model and greedy algorithm. The UGAS scheme divides the Contention-Free Period into time slots of different durations to support various bandwidth requirements. Time slots are allocated using an approximation QoS model to minimize under-utilization. Compared with the standard GTS allocation scheme, UGAS makes an efficient bandwidth allocation with the QoS-guaranteed model and without breaking the standard protocol. The numerical results show that the average bandwidth utilization using UGAS can be improved by 30 % as compared with the standard scheme. 相似文献
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Wireless Local Area Network (WLAN) with high data bit rates can be used with cellular network to achieve higher level of Quality of Service (QoS) by sharing their total resources efficiently. The integration between cellular and WLAN networks should be ensured considering different channel allocation strategies of both networks and efficient resource management techniques should be developed. In this paper, we propose a new call admission scheme to use the coupled resource effectively. The proposed scheme, by taking the different resource sharing strategies for two access networks, limits the new, horizontal and vertical handoff voice and data call arrivals with respect to their call level QoS requirements. Numerical results show that the proposed integrated cellular/WLAN network model uses the resources more effectively and achieves all upper bound QoS requirements for voice and data users as compared with the non integrated network model. 相似文献
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IEEE802.15.4标准定义了无线个域网的物理层和MAC层规范,它的突出特点是低速率、低功耗。文章介绍了该标准的特性,说明了其物理层、MAC层工作的过程。符合该标准的接收机结构有两种:低中频和零中频;发射机结构也有两种:直接上变频和VCO调制。文章对这几种结构进行了分析,比较了其优缺点。 相似文献
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移动宽带无线接入技术是一种覆盖范围非常广泛的技术.本文介绍了IEEE 802.20标准的技术特点,并将其与IEEE 802.16和3G标准进行了对比.提出了一种基于802.20标准的技术方案构建无线城域网.文章最后展望了未来的发展方向. 相似文献
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基于IEEE 802.20标准构建无线城域网 总被引:3,自引:0,他引:3
IEEE 802.20作为一种新的移动无线通信技术标准虽然尚处于讨论阶段,但该标准有可能大大激活数据业务的市场需求.文章介绍了lEEE 802.20标准的制定进程、技术发展趋势以及主要技术特点,并根据IEEE 802.20的技术特点,给出了未来无线城域网架构以及单纯利用lEEE 802.20设备构建无线城域网的模型. 相似文献
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Providing Throughput Guarantees in 802.11e WLAN Through a Dynamic Priority Assignment Mechanism 总被引:1,自引:0,他引:1
Antonio Iera Giuseppe Ruggeri Domenico Tripodi 《Wireless Personal Communications》2005,34(1-2):109-125
Supporting real-time and interactive traffic in addition to traditional data traffic with a best-effort nature represents
a constantly rising need in any kind of telecommunications environment. The IEEE 802.11 based WLAN (Wireless Local Area Network)
environment does not represent an exception. This is why at different protocol layers, and primarily at the MAC layer, many
efforts are being put by both the research community and the standardization bodies to design effective mechanisms for user
QoS (Quality of Service) differentiation. Although early results are coming into sight, such as, for example, the IEEE 802.11e
standard release, still a thorough research activity is required. Aim of the present paper is to contribute to the cited research
issue by proposing an improvement to the “static” traffic prioritisation mechanism foreseen by the IEEE 802.11e MAC (Medium
Access Control) protocol. This latter shows a twofold drawback. First, there is no certainty that QoS requirements relevant
to a given application are always fulfilled by the “statically” associated priority. Second, resource requests of the applications
are not adapted to the (usually highly) variable traffic conditions of a distributed WLAN environment. The algorithm we propose
is specifically tailored to “dynamically” assign 802.11e MAC priorities, depending on both application QoS requirements and
observed network congestion conditions. It is carefully designed, implemented into a system simulation tool, and its highly
effective behaviour assessed under variable traffic and system conditions.
Antonio Iera graduated in Computer Engineering at the University of Calabria, Italy, in 1991 and received a Master Diploma in Information
Technology from CEFRIEL/Politecnico di Milano, Italy, in 1992 and a Ph.D. degree from the University of Calabria, Italy, in
1996. From 1994 to 1995 he has been at the Mobile Network Division Research Center, Siemens AG Muenchen, Germany to participate
to the CEC Project “RACE II 2084 ATDMA (Advanced TDMA Mobile Access)” under a “Commission of European Communities Fellowship
Contract in RACE Mobility Action”. He has been with the University of Reggio Calabria, Italy, from 1997 to 2000 as Assistant
Professor, and from 2001 to 2005 as Associate Professor. Currently, he is Full Professor of Telecommunications at the same
University. In 1995 and in 1996 he has been the recipient of an IEEE Paper Award for the papers presented at the IEEE International
Conference on Universal Personal Communications ICUPC'95, and an IEICE/IEEE Outstanding Paper Award for the paper presented
at the IEEE ATM Workshop'99, respectively. He served as member of Technical Program Committees of several International Conferences,
and in 2003 he has been co-Guest Editor for the special issue “QoS in Next-generation Wireless Multimedia Communications Systems”
in the IEEE Wireless Communications Magazine. His research interests include QoS control and resource management in Personal
Communications Systems and Enhanced Wireless and Satellite Systems.
Giuseppe Ruggeri received the degree in electronics engineering from the University of Catania, Italy, in 1998. He received the Ph.D. degree
in electronics, computer science and telecommunications engineering with a dissertation on “Advanced Methods to Improve the
QoS in VoIP Systems Based on VBR Speech Coders”. His interests include the field of adaptive-rate voice transmission for IP
Telephony applications, and support of Quality of Service in heterogeneous wireless networks and WLAN-3G interconnection-integration
. He is currently Assistant Professor in the Department of Computer Science, Mathematics, Electronic and transportation systems
(DIMET) at the University “Mediterranea” of Reggio Calabria. His mail address is ruggeri@ing.unirc.it.
Domenico Tripodi received M.S. degree (cum laude) in electronic engeneering from the University ‘Mediterranea' of Reggio Calabria, Italy in
2003. He won a post-degree scholarship from CNIT in 2004, and he is currently at CNIT Research Unit of Reggio Calabria. His
reasearch interest are in the area of QoS provisioning in Mobile Ad-Hoc Networks. 相似文献