Wireless MANs (metropolitan area networks) differ from wireless LANs and wireless PANs in that they are not usually implemented by the organization that wishes to use the network. Instead, they are generally implemented by a service provider, and then access to the network is leased by each subscribing organization. However, unlike with wireless WANs, this does not have to be the case. For example, 802.16 -compliant hardware could be purchased and frequency licenses could be acquired in order to implement a private wireless MAN, but the expense is usually prohibitive. WiMAX is the most commonly referenced wireless MAN technology.
WiMAX
In 2007, WiMAX solutions are just beginning to see production and installation. In fact, the first WiMAX Professional Certification training class was held in Hawaii, in January and February 2007.
WiMAX is based on the IEEE 802.16 standard and provides expected throughput of approximately 40 Mbps for fixed, line of sight connections and approximately 15 Mbps for mobile, non-line of sight connections. In addition to the throughput speeds, WiMAX incorporates QoS mechanisms that help to provide greater throughput for all users and important applications using the network.
A wireless Internet service provider (WISP) is an Internet service provider (ISP) that is accessed using wireless technologies. WISPs often fulfil the need at the 'last mile’, which refers to the last section that must be spanned to reach remote customers. It can be very expensive and, without wireless, sometimes impractical. Sometimes these WISPs lease bandwidth to businesses that require Internet access, but that are too far from DSL stations and have no other options.
Wireless technologies used by WISPs
WISPs may use IEEE 802.11 technologies for the entire delivery, or they may use other wireless technologies, like WiMAX (IEEE 802.16), from the operations centre to the delivery area and then use IEEE 802.11 technologies within the delivery area. Other WISPs use WiMAX all the way to the end destination, meaning it is then up to the subscriber whether to use IEEE 802.11 technologies within their house or business.
Since WiMAX and IEEE 802.11 use different frequencies (if the 802.11 devices use the 2.4 GHz spectrum), there should be no conflicts or interference.
Last-mile delivery
To help you understand last-mile delivery, consider the home where my friend grew up in West Virginia of the United States. They lived on a very old country road. It was not paved; it was a gravel road. They lived in the last house on the road, which was approximately 2.5 miles from the nearest paved road. They had to pay a large fee just to get electricity to the house. The electric company required such a fee since there were no other houses close to theirs.
This is an example of the problems related to last-mile delivery. It’s no different for the Internet today than it was for electricity then. Wireless technologies provide an excellent solution to the problem of last-mile delivery of Internet access.
In Hong Kong, WiMAX's advantage of enabling last-mile deliveries to remote users economically may not be so convincing since the density of population is extremely high here, and ISPs have enough incentive to pave the last mile for nearly every household. But another strength of WiMAX that does apply to Hong Kong is that it can offer the last mile connection for those endpoints that are 'on the move' (e.g. PDAs, notebooks, etc.) .
WiMAX's provision of last mile connection for mobile endpoints
As you might expect, this capability is well-received by local users, given the high popularity of handheld devices here. Currently, the wireless connections used by these handheld devices are mainly provided by the existing mobile networks. However, the throughput of the mobile networks, even 3G, can reach only a few mega bits per second, which is much lower than WiMAX (45Mbps). It is therefore foreseen that WiMax will have plenty of scope to develop in Hong Kong.
Please read the following material to learn more about 802.11 and 802.16 (WiMAX) Internet access:
Reading
Dean (2010) 396–97.
Check if you have grasped the topics we have convered in this section by attempting Self-test 3. Remember, don't look at the Suggested answers to Self-test 3 before answering the questions.
In Hong Kong, the government has launched a programme to provide free wireless Internet access services to all citizens. Learn more about the programme by answering the questions in Activity 4 and reading the Feedback to Activity 4 afterwards.
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