Why is WiMAX needed?
To answer this question it is important to understand the state of technical
fragmentation experienced in the past by the mobile wireless and fixed broadband
wireless industry. Early broadband wireless systems began as extensions of
indoor local area network (LAN) technology known as Wi-Fi or the 802.11b
protocol. This standard has evolved into a ubiquitous and widely available
standard used in short range hotspots all over the globe. However, the media
access controller (MAC) and physical layer (PHY) specifications for this
protocol are suboptimum for outdoor citywide wireless networks or metropolitan
area networks (MAN). Recent updates and new standards such as 802.11g, 802.11a
and 802.11n have improved these elements. However, once again these technologies
are configured for best performance in small venues and at short range.
It should be noted that recent developments in the ratification standard of the
IEEE 802.11n protocol offer the promise of significant improvements to
Wi-Fi---improvements that will blur the lines of capability between WLAN and
more robust WMAN (wireless metropolitan area network) systems somewhat. There
are numerous 802.11n products on the shelf and being marketed vigorously,
despite that fact that the standard is not yet finalized. While 802.11n is not
necessarily optimized for great range, its bandwidth capabilities are a major
leap ahead from Wi-Fi. Its range improvements in the hotspot will be significant
also. However, despite hopes for a final standard this specification remains
mired in the competing desires of various camps and their approaches to its
implementation. A number of companies, including, Belkin, D-Link, Linksys and
others have nevertheless launched Pre-N or pre-certified 802.11n products. These
offer solid improvement over even 802.16a/g systems; however, early testing by
ZDNet has shown that the gains remain modest. Also, interoperability between the
various products is problematic at best. The standard appears set to be
finalized near the end of 2009 which has clearly been the biggest holdup for the
technology.
To compensate for deficiencies in early Wi-Fi technology, vendors developed
proprietary MAC and PHY layers based on the root LAN standard of 802.11. Many of
these systems are in use today and possess significant improvements in
modulation scheme, polling technology and data transport that enable effective
and modestly affordably citywide or rural wireless networks. However, none of
these proprietary iterations of the technology are exactly the same. No two
companies' products will work with each other. This means that broadband
wireless carriers must use base stations and customer premise equipment from the
same vendor in any given city---which may not be the best solution in some
geographic and radio frequency (RF) environments.
Some of these radio vendors were even forced to manufacture their own silicon
chips to deliver technical improvements. The high costs for equipment resulting
from this approach significantly slowed adoption of broadband fixed wireless
versus cheaper mass market technologies such as DSL and Cable modem service.
In the mobile arena, the standards for broadband wireless delivery are less
fragmented. More importantly however, the cost, speeds delivered and time to
market of broadband mobile solutions have been suboptimum. But that is changing.
The promise of 3G services was slow to emerge. but that is changing with wide
deployments coming from Verizon using its EVDO system as well as from Sprint and
AT&T Wireless, which is widely deploying its HSDPA 3G system, mobile WiMAX
systems based on newer technology such as OFDMA® offer the promise of cheaper,
more effective and faster deployments of broadband mobile wireless systems. More
recently 3G deployments do appear to have accelerated with a number of
high-profile GSM-friendly broadband technology (called UMTS or its updated
version HSDPA) have gained some traction, mostly in Europe. In the US, Sprint is
in the process of rolling out a CDMA network with the newer and faster
Revision-A version. Perhaps most importantly, the advent of WiMAX has greatly
accelerated long-held plans by cellular carriers worldwide on the Long Term
Evolution (LTE) standard, which offers strong promise of a new generation of
truly broadband capable wireless handsets and modems. And longer term there is
potential, if not yet perhaps the technology political will, for a merging of
WiMAX and LTE. LTE does appear about two years behind WiMAX systems.
