HiperLAN/2下一代的无线局域网技术

HiperLAN／2是欧洲ETSI为了满足未来的Internet访问和宽带多媒体数据业务的需求，开发新一代的WLAN技术标准，它在5CHz的频段上运行，它采用OFDM作为物理层，因而可以有效对抗多径干扰，提高数据速率。另外由于采用和802．11a相同的物理层，因此它们可以共享一些相同的部件，从而在较大的范围内降低系统成本。对HiperLAN／2的特点和协议栈结构作了简单介绍。     

HiperLAN／2下一代的无线局域网技术

HPERLAN/2是欧洲ETSI为了满足未来的Internet访问和宽带多媒体数据业务的需求，开发的新一代的WLAN技术标准，它在5GHA的频段上运行，它采用OFDM作为物理层，因而可以有效地对抗多径干扰，提高数据速率。另外由于采用和802.11a相同的物理层，因此它们可以共享一些相同的部件，从而在较大的范围内降低系统成本，本对HiperLAN/2的特点和协议栈结构作了简单介绍。     

高性能无线局域网HiperLAN/2

文章介绍了新兴的高性能无线局域网标准HiperLAN／2，全面分析了它的系统结构、协议体系和技术特点，并对两种无线局域网标准HiperLAN／2和IEEE802．11的技术特点进行了比较。     

未来高速无线局域网HiperLAN/2标准

无线局域网(WLAN)是计算机网络与无线通信技术结合的产物,通过无线信道接入网络,使通信的移动化、个人化和多媒体应用成为可能,是宽带无线接入的有效途径之一。目前,无线局域网处于众多标准共存时期,主要原因是技术发展太快,标准跟不上技术发展。为了满足未来访问Internet和宽带多媒体数据业务的需求,一些标准化组织开发了新一代WLAN技术标准,其中最引人注目的是美国的IEEE802.11a和欧洲电信标准协会(ETSI)的HiperLAN/2,工作在5GHz频段,速率可达54Mb/s。本文详细介绍HiperLAN标准中的HiperLAN/2。1HiperLAN/2标准ETSI的Hip…     

无线局域网HiperLAN／2标准综述

概述了HiperLan／2标准，以及链路和系统的性能。     

下一代无线局域网标准--HiperLAN/2

文章介绍了HiperLAN/2这一无线局域网标准,列举了基于HiperLAN/2的网络的特点,详细描述了HiperLAN/2的协议栈结构,最后给出了基于HiperLAN/2的无线网络的功能。     

宽带可移动无线接入系统关键技术:HiperLAN/2

迅速发展的Internet业务、多媒体业务以及日益增长的移动电话用户都预示着未来几年中,宽带无线技术将在通信领域中快速发展。文章介绍了可移动无线宽带系统中HiperLAN/2的工作原理及其体系结构,并指出了HiperLAN/2的系统特征。     

HiperLAN/2--5GHz频段的宽带无线传输技术

本文介绍了一种先进的无线局域网（WLAN）技术HiperLAN/2，它工作在5GHz频段，物理层采用OFDM调制，最高速率可达54Mbit/s，支持QoS及安全性管理，能对频率进行自动管理，并在物理层进行适配，是WLAN未来一个重要的发展方向。     

下一代高性能无线局域网技术

HiperLAN/2是一种由ETSI制订的高性能的无线局域网标准，它提供了54Mbit/s的传输速率。本对HiperLAN/2协议体系结构、HiperLAN/2网络应用与特点进行了介绍，并对其与GPRS／UMTS网络的互联进行了论述。     

高性能无线局域网简介

随着无线分组数据的发展,人们对数据传输速度的要求越来越高。其中,高性能无线局域网(HiperLAN/2)是欧洲提出的一种解决方案。文章主要针对这一标准的协议和实现原理进行介绍。     

下一代高性能无线局域网技术

HiperLAN/2是一种由ETSI制订的高性能的无线局域网标准,它提供了54Mbit/s的传输速率。本文对HiperLAN/2协议体系结构、HiperLAN/2网络应用与特点进行了介绍,并对其与GPRS/UMTS网络的互联进行了讨论。     

HiperLAN/2与GPRS/UMTS网络的互联--全新的高速广域无线接入业务模式

本在介绍无线局域网HiperLAN／2标准及GPRS／UMTS网络的体系结构的基础上，对HiperLAN／2与GPRS／UMTS网络的互联进行了讨论。有两种不同的互联方式：紧耦合互联方式和松耦合互联方式，由于松耦合互联方式对GPRS／UMTS网络的影响最小，本重点对其安全性、移动性和QoS问题进行了讨论。     

HiperLAN/2——下一代WLAN标准

本文详细分析了HiperLAN/2(高性能无线局域网)技术标准的网络结构、技术特点、协议栈和工作原理,并由此预言其将成为最有竞争力的无线局域网标准之一。     

HiperLAN/2系统的技术特点与分析

HiperLAN/2系统是继IEEE802.11之后发展起来的最新一种宽带无线本地网络系统,该系统提供了高达54Mbps物理层传输速率,满足不同QoS要求的面向连接的传输功能及能够灵活接入各种高层网络的协议结构。对该系统的技术特点、协议栈结构以及技术指标和典型应用进行分析。     

下一代WLAN技术标准802.11ac/ad

基于IEEE802.11n标准的WLAN能够支持高达600 Mbit/s的传输速率,但在支持无线高清视频传输等高吞吐量无线数据业务时仍然会遇到瓶颈。面对这一挑战I,EEE已启动下一代WLAN技术标准802.11ac和802.11ad的制定工作,数据吞吐量将达到几个Gbit/s,能够更好地满足快速增长的市场需求。     

WLAN/WPAN环境中模拟退火动态频率选择算法的研究

动态频率选择(DFS)是解决频道实时优化的有力手段，本文针对无线局域网，无线个域网(WLAN／WPAN)等小区域无线多媒体通信系统，首次把模拟退火算法应用到DFS中，针对WLAN／WPAN的情况，给出其处理过程的完整描述，并以HiperLAN／2系统为例进行了仿真。仿真结果表明，与目前已有的算法相比较，新算法实现了整个系统的组合优化，克服了现有算法可能存在的跳转较频繁、性能不够稳定等缺点，能在复杂传播环境下提高WLAN／WPAN的服务质量(QOS)。     

Resource Allocation and Wireless Scheduling Scheme for a HiperLAN/2 System

In this paper, a dynamic resource allocation scheme for a wireless local area network system is presented. It aims at enforcing the Quality of Service requirements of the applications that are carried on the wireless link even when errors occur on it. The allocation takes benefit from the coexistence of connections that have different QoS tolerances so that, when facing errors, the bandwidth allocated to the more tolerant connections could be reduced and attributed to the connection with more stringent QoS requirements to perform retransmissions. For that purpose, two classes of Quality of Service are considered that are related to Constant Bit Rate traffics and best-effort traffics. The scheduling framework is then based on a hierarchical rate-based fair queuing algorithm and is extended in order to cope with error. To illustrate its operation, the proposed scheme is applied to the ETSI HiperLAN/2 WLAN. Some simulation results are reported and show the impact of the scheduling principles on best-effort traffics such as TCP applications and its actual benefits for CBR traffic. The efficiency of the proposed mechanism is evaluated using measurement of delays and throughputs at Data Link Layer level. The aim of this paper is not so much to prove the fairness of this mechanism but rather its ability to guarantee negotiated services required by heterogeneous applications.Christophe Mangin is a research engineer at Mitsubishi Electric ITE-TCL. He received degrees in Electrical Engineering from Institut National des Sciences Appliquées (INSA), Rennes, France, in 1988, and in VLSI architecture from Université Paris VI, in 1989. From 1989 to 1991, he was with ALCATEL SEL, Stuttgart, Germany, where he was involved in parallel DSP design for image processing. From 1991 to 1999, he worked at France Telecom R&D, Lannion, France, in the field of packet switch/router architectures, ATM resource management techniques, and Internet network architecture. In 1999, he joined Mitsubishi Electric ITE’s Telecommunication Laboratory, Rennes, France. His present research interests include broadband wireless systems and wireless-wired network interoperability with a special focus on quality of service mechanisms for Internet applications in heterogeneous networks.Gwillerm Froc received the PhD degree in Physics in 1997 from the University of Paris XI. At that time, his research interests were related to the optical telecommunications field. Then, he worked at France Telecom R&D on reliable multicast protocols on IP for satellite broadcasting. He joined Mitsubishi Electric ITE in 2001. His main scientific and engineering interests now deal with performances and modelling of wireless systems. They currently focus on MAC protocols.Romain Rollet received his M.Sc. in electronics and computer engineering from the Ecole Supérieur d’Electricité (Supelec), France in 1998. In 2000, he joined Mitsubishi Electric Telecom Laboratory in Rennes where he has participated to the development and implementation of a complete HiperLAN/2 prototype. His current research areas are mostly related to Data Link layer and interactions between physical and MAC layers in future WLAN systems. He is the author or co-author of several pending patents.