wilamowski-b-m-irwin-j-d-industrial-communication-systems-2011

WiMAX in Industry 52-3
However, the terms fixed WiMAX, mobile WiMAX, “802.16,” “802.16d,” and “802.16e” are frequently
used incorrectly. The clarifications follow:
• The IEEE 802 Standards Committee develops LAN standards and MAN standards [3], available
for download at http://standards.ieee.org/getieee802/.
• The IEEE 802.16 Working Group on broadband wireless access standards develops standards
and recommended practices to support the development and deployment of broadband
WirelessMAN [4].
• 802.16-2004 is often called 802.16d, named after the IEEE Standard “Task Group d” that produced
it and covers the “Air Interface for Fixed Broadband Wireless Access Systems.” Specifically,
IEEE Standard 802.16 revised by the Task Group d resulted in 802.16-REVd, later on published
as 802.16-2004 (replacing IEEE Standards 802.16-2001, 802.16c-2002, and 802.16a-2003) [5]. It is
also frequently referred to as “fixed WiMAX” since it has no support for mobility.
• 802.16e-2005 is often called 802.16e, named after the “Task Group e” that developed it. This
amendment to IEEE Standard 802.16 is covering “PHY and MAC layers for combined fixed and
mobile operation in licensed bands.” It introduced support for mobility, among other things and
is, therefore, also known as “mobile WiMAX” [6,7].
52.2 the WiMAX Broadband Technology
Growing popularity of WiMAX broadband access technology, similarly to cellular phone technologies
such as global system for mobile communications or GSM (originally from groupe spécial mobile) and
code division multiple access or CDMA, is becoming especially evident in rural areas, as it does not
require wired broadband connections.
It is to be expected that WiMAX will, in addition to being used as a wireless backhaul technology for 2G,
3G, and 4G networks, be also instrumental in further deployment and growth of Wi-Fi hotspots. While
current operation of most Wi-Fi hotspots is based on wired broadband connections, in future, WiMAX
could serve as a faster and cheaper alternative to wired backhaul for these hotspots. Using the point-tomultipoint
transmission capabilities of WiMAX to serve as backhaul links to hotspots could substantially
improve the business case for Wi-Fi hotspots and provide further momentum for hotspot deployment [8].
52.2.1 Backhaul/Access Network Applications
Backhaul, in telecommunications, typically refers to intermediate links between the backbone and
smaller subnetworks of the overall network (local access points [APs] and the backbone network) [2].
The potential to serve as the backhaul connection to the rapidly increasing market of Wi-Fi hotspots
paved the way for the WiMAX in the urban but also in non-urban areas. An exploding number of Wi-Fi
hotspots is being deployed in public areas such as convention centers, hotels, airports, and coffee shops
in the United States and other developed markets [8]. In addition, WiMAX technology can serve as
overlay to cable, DSL, data and telecommunication services. Often advertised as the “combination of the
mobility you love about your cell phone with the speed you want from broadband,” WiMAX providers
are continually growing the coverage of “portable Internet” and “Broadband On The Go” [9–11].
Deploying WiMAX in rural areas with limited or no Internet backbone will be challenging as
additional methods and hardware will be required to procure sufficient bandwidth from the nearest
sources—the difficulty being in proportion to the distance between the end user and the nearest sufficient
Internet backbone.
A WiMAX tower station can connect directly to the Internet either via a broadband wired connection
or to another WiMAX tower using a microwave, line-of-sight link (LOS). The advantageous characteristic
of WiMAX is exactly the backhaul, i.e., the ability to bridge the rural areas via LOS connection to
another tower.
© 2011 by Taylor and Francis Group, LLC