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Hiperlan 2

INTRODUCTION

Recently, demand for high-speed Internet access is rapidly increasing and a lot of people enjoy broadband wired Internet access services using ADSL ( Asymmetric Digital Subscriber Line) or cable modems at home. On the other hand , the cellular phone is getting very popular and users enjoy its location-free and wire -free services. The cellular phone also enables people to connect their laptop computers to the Internet in location-free and wire-free manners. However , present cellular systems like GSM (Global System for Mobile communications) can provide much lower data rates compared with those provided by the wired access systems, over a few Mbps(Mega bit per second).Even in the next generation cellular system, UMTS ( Universal Mobile Telecommunications System), the maximum data rate of its initial service is limited up to 384 kbps; therefore even UMTS cannot satisfy usersâ„¢ expectation of high-speed wireless Internet access. Hence, recently, Mobile Broadband System (MBS) is getting popular and important and wireless LAN (Local Area Network) such as ETSI (European Telecommunication Standardization Institute) standard HIPERLAN (High PErformance Radio Local Area Network) type2 (denoted as H/2) is regarded as a key towards providing high speed wireless access in MBS. H/2 aims at providing high speed multimedia services, security of services , handover when roaming between local and wide area as well as between corporate and public networks. It also aims at providing increased throughput of datacom as well as video streaming applications. It operates in the 5 GHz band with a 100 MHz spectrum. WLAN is W-ATM based and is designed to extend the services of fixed ATM networks to mobile users. H/2 is connection oriented with a connection duration of 2 ms or multiples of that. Connections over the air are time-division multiplexed . H/2 allows interconnection into virtually any type of fixed network technology and can carry Ethernet frames, ATM cells and IP packets. Follows dynamic frequency allocation. Offers bit rates of 54 Mbps.

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1.0 INTRODUCTION
The need for mobile broadband communications has increased rapidly in recent years placing new demands for the wireless local area networks (WLANs). These requirements include support for QoS, security, handover, and increased throughput. To answer these needs, the European Telecommunications Standards Institute (ETSI) is working on HIPERLAN (Hlgh Performances LAN) standards of various types. These standards merely describe the low-level interfaces and leave the higher level functions open. This essay will concentrate on HIPERLANM, a state-of-the-art WLAN technology that has been developed to provide a wireless access to fixed networks. This is intended to be a short overview of its main features and protocol reference model. For several years, the technical committee RESlO (Radio Equipment And Systems) of ETSI (European Telecommunications Standards Institute) has been working on HIPERLAN (Hlgh Performance LAN), which is a family of standards on digital high speed wireless communication in the 5.15-5.3 Ghz and the 17.1-17.3 Ghz spectrum. ETSl is currently referring the family as BRAN (Broadband Radio Access Networks). Four types of HIPERLAN has been proposed: HIPERLAN types 1 and 2, HIPERACCESS and HIPERLINK. The HIPERLAN standard merely describes a common air interface and the physical layer for wireless communications equipment, thus ensuring compatible communications systems while leaving the higher level functions open to the manufacturers. Its specification consists of the two lowest layers of the OSII model.Unlike the HIPERLAN type 1, the HIPERLAN type 2 has been specifically developed to mainly have a wired infrastructure providing a short range 7.%rirelessa ccess to IP, ATM and UMTS networks. interface; while on the move, HIPERLANM automatically performs handover to the nearest AP. Ad hoc networks, where the MTs communicate directly, can also be created, but their development is still in early phase. The HIPERLANM is planned to be finalized by the end of 1999.

INDEX
Chapter Contents Page No.
1. Introduction. 1
2. Hiperlan 1. 3
3. Hiperlan 2. 4
4. Layers. 6
5. Hiperlan History. 12
6. Hiperlan Family. 13
7. Hiperlan Vision. 14
8. Hiperlan Packets. 15
9. Hiperlan Specifications. 16
10. Hiperlan Features. 17
11. Conclusion 18
2. References 19


11.0 CONCLUSION The need for mobile broadband communications has increased rapidly in recent years placing new demands for the wireless local area networks (WLANs). According to all these factors it is clear that by using HIPERLAN there are many advantages Thus we can conclude that HiperLan is a very good discovery in the wireless technology.

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Hiperlan 2
INTRODUCTION

Recently, demand for high-speed Internet access is rapidly increasing and a lot of people enjoy broadband wired Internet access services using ADSL ( Asymmetric Digital Subscriber Line) or cable modems at home. On the other hand , the cellular phone is getting very popular and users enjoy its location-free and wire -free services. The cellular phone also enables people to connect their laptop computers to the Internet in location-free and wire-free manners. However , present cellular systems like GSM (Global System for Mobile communications) can provide much lower data rates compared with those provided by the wired access systems, over a few Mbps(Mega bit per second).Even in the next generation cellular system, UMTS ( Universal Mobile Telecommunications System), the maximum data rate of its initial service is limited up to 384 kbps; therefore even UMTS cannot satisfy users’ expectation of high-speed wireless Internet access. Hence, recently, Mobile Broadband System (MBS) is getting popular and important and wireless LAN (Local Area Network) such as ETSI (European Telecommunication Standardization Institute) standard HIPERLAN (High PErformance Radio Local Area Network) type2 (denoted as H/2) is regarded