HIPERLAN
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HIPERLAN is a WLAN standard. It is a European alternative for the IEEE 802.11 standards (the IEEE is an American organization). It is defined by the European Telecommunications Standards Institute (ETSI). In ETSI the standards are defined by the BRAN project (Broadband Radio Access Networks). The HIPERLAN standard family has four different versions.
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HIPERLAN/1
Hiper Lan is Essentially 802.11a N/W and it is Different from 802.11b/g. HIPERLAN/1, HIgh PErformance Radio LAN version 1 is an ETSI standard. The planning started 1991, when planning of 802.11 was already going on. The goal of the HIPERLAN was the high data rate, higher than 802.11. The standard was approved 1996. The functional specification is EN300652, the rest is in ETS300836.
The standard covers the physical and the MAC part of the Data Link layers like 802.11. There is a new sublayer called Channel Access and Control sublayer (CAC). This sublayer deals with the access requests to the channels. The accomplishing of the request is dependent on the usage of the channel and the priority of the request.
CAC layer provides hierarchical independence with Elimination-Yield Non-Preemptive Multiple Access mechanism (EY-NPMA). EY-NPMA codes priority choices and other functions into one variable length radio pulse preceding the packet data. EY-NPMA enables the network to function with few collisions even though there would be a large number of users. Multimedia applications work in HIPERLAN because of EY-NPMA priority mechanism. MAC layer defines protocols for routing, security and power saving and provides naturally data transfer to the upper layers.
On the physical layer FSK and GMSK modulations are used in HIPERLAN/1.
HIPERLAN features:
- range 50 m
- slow mobility (1.4 m/s)
- supports asynchronous and synchronous traffic
- sound 32 kbit/s, 10 ns latens
- video 2 Mbit/s, 100 ns latens
- data 10 Mbit/s
HIPERLAN does not conflict with microwave and other kitchen appliances, which are on 2.4GHz.
HIPERLAN/2
HIPERLAN/2 functional specification was accomplished February 2000. Version 2 is designed as a fast wireless connection for many kinds of networks. Those are UMTS back bone network, ATM and IP networks. Also it works as a network at home like HIPERLAN/1. HIPERLAN/2 uses the 5 GHz band and up to 54 Mbit/s data rate.
Basic services are data, sound, and video transmission. The emphasis is in the quality of these services (QoS).
The standard covers Physical, Data Link Control and Convergence layers. Convergence layer takes care of service dependent functionality between DLC and Network layer (OSI 3). Convergence sublayers can be used also on the physical layer to connect IP, ATM or UMTS networks. This feature makes HIPERLAN/2 suitable for the wireless connection of various networks.
On the physical layer BPSK, QPSK, 16QAM or 64QAM modulations are used.
Good security measures are offered by HIPERLAN/2. The data are secured with DES or 3DES algorithms. The access point and the wireless terminal can authenticate each other.
HIPERLAN: already obsolete, or future technology?
Some people believe that the IEEE 802.11 standards have already occupied the niche that HIPERLAN was designed for, albeit with lower performance but higher market penetration, and that the network effect of existing deployment will prevent the adoption of HIPERLAN. They also state that, since the primary use of WLANs is to provide Internet access, the lack of QoS support in the commercial Internet will make the support for QoS in access networks irrelevant.
Others believe that the superior technical performance of HIPERLAN/2 can offer new services that 802.11 variants are incapable of delivering.
The development of 802.11n, which will define the next level of performance in WLANs, is not paralleled by any further attempt at HIPERLAN activity.