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HIPERLAN2 for Broadband Wireless Communication
Overview
Within
a couple of years from now, wireless LANs will be operating at speeds up to
54Mbps. There are currently two main standards being developed to make
this possible, HiperLAN2 and the counterpart: IEEE 802.11a, whether they will
both survive the development/implementation stage, which one will be more
widely accepted, and in which part of the world they each will be implemented
are all the subjects of debate within the wireless industry.
Wireless
networking is quite simply a network that distributes data between computers
and/or other multimedia devices, but via radio waves rather than wires.
Wireless Local Area Network (WLAN), which enables people to freely connect to
their corporate LAN, is rapidly growing in popularity and application.
HiperLAN2
is one global broadband wireless technology in the 5 GHz frequency band that
intends to provide universal connectivity for mobile devices in corporate,
public, and home environments. The use of the 5 GHz frequency band was
initiated in recognition of the various limitations of the 2.4 GHz band.
Licensing authorities around the world have allocated large blocks of spectrum
in the 5 GHz band, these blocks of spectrum & lenient operating rules
enable high-speed operation by large numbers of users.
HiperLAN2
promises to provide mobility, and high-speed transmission with a raw
over-the-air data rate of 54 Mbps at the physical layer, i.e., the sustained
throughput for applications at 20 Mbps. For real-time applications such as
voice and video, HiperLAN2 also offers QoS (quality of service) guarantee,
which is based on the characteristic of a connection-oriented network where
data is transmitted between mobile terminals and access points on connections
that have been established prior to transmission.
HiperLAN2
is included in an ETSI (European Telecommunications Standards Institute) BRAN
(Broadband Radio Access Network) project which works towards the following
standards: HiperLAN1, HiperLAN2, HiperLink (designed for indoor radio
backbones) and HiperAccess (designed for fixed outdoor use to provide access to
wired infrastructure).
Many
of the founding members of the HiperLAN2
Global Forum, with the exception of Texas
Instruments and Dell, are European. They
include Bosch, Ericsson, Nokia
and Telia. Later on, Alcatel, Cambridge Silicon Radio, Grundig, Siemens
and Philips added themselves to the list,
along with other companies in the United States (Motorola, Silicon Wave) and Japan (Canon, NTT).
HiperLAN2
General Features
The
general features of the HiperLAN2 technology can be summarized here:
- High-speed transmission
- Connection-oriented
- Quality-of-Service (QoS) support
- Automatic frequency allocation
- Security support
- Network & application independent
- Saving power
QoS Support
This
is the main difference between HiperLAN2 and IEEE 802.11a, it is recognized by
both sides to various degrees that HiperLAN2's ability to offer solid QoS is a
whole lot more promising in terms of supporting streaming video and other
multimedia applications.
The
connection-oriented nature of HiperLAN2 makes it straightforward to implement
QoS support. Each connection can be assigned a specific QoS, for instance in
terms of bandwidth, delay, jitter, bit error rate, etc. It is also possible to
use a more simplistic approach, where each connection can be assigned a
priority level relative to other connections. This QoS support in combination
with the high transmission rate facilitates the simultaneous transmission of
many different types of data streams, e.g. video, voice, and data.
Spectrum Allocation and Area
Coverage
In
A cell of a HiperLAN2 AP (Access Point) typically extends to approximately 30
(office indoor) – 150 meters.
Figure 1 shows the current status regarding frequency allocation in US,
Figure 1: Spectrum allocation in 5 GHz (left) and spectrum rules on 5
GHz (right).
Last revised: Nov.
07, 2001, by Lei Fang & Wengyi Zhang
This webpage is
for academic use only.