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A wireless MAN based on the WiMAX-air interface standard is configured in much the same way as a traditional cellular network with strategically located base stations using a point-to-multipoint architecture to deliver services over a radius up to several kilometres depending on frequency, transmit power and receiver sensitivity. In areas with high population densities the range will generally be capacity-limited rather than range limited due to limitation in the amount of available spectrum. The base stations are typically backhauled to the core network by means of fibre or point-to-point microwave links to available fibre nodes or via leased lines from an incumbent wireline operator.
The range and NLOS capability makes the technology equally attractive and cost-effective in a wide variety of environments. The technology was envisioned from the beginning as a means to provide wireless last-mile broadband access in the MAN with performance and services comparable to or better than traditional DSL, Cable or T1/E1 leased-line services.
5.2 LAST-MILE HIGH-SPEED INTERNET ACCESS OR WIRELESS DSL
DSL operators, who initially focused their deployments in densely populated urban and metropolitan areas, are now faced with the challenge to provide broadband services in suburban and rural areas where new markets are quickly taking root. Governments are prioritizing broadband as a key political objective for all citizens to overcome the ‘broadband gap’ also known as the ‘digital divide’ (Figure 5.3).
Figure 5.3 Last-mile
Large and Medium-sized Enterprises
Broadband Internet connectivity is mission critical for many businesses, to the extent that these organizations may actually relocate to areas where the service is available. In today’s market, only 5 % of commercial structures worldwide are served by fibre networks, the main method for the largest enterprises to access broadband, multimedia data services. In the wired world, these networks are extended to the business or residence via cable or DSL, both expensive options because of the infrastructure changes required. DSL typically operates at 128 kbps to
1.5 mbps, slower on the upstream. Further, local exchange carriers have been known to take three months or more to provision a T1 line for a business customer, if the service is not already available in the building.
Older buildings in metropolitan areas can present a tangle of wires that makes it difficult to deploy broadband connections to selected business tenants. Enterprises can use WiMAX instead of T1 for about 10 % of the cost. IEEE 802.16a wireless technology enables a service provider to provision service with a speed comparable to a wired one. In addition, the range of IEEE 802.16 solutions, the absence of a line-of-sight requirement, high bandwidth, and the inherent flexibility and low cost help to overcome the limitations of traditional wired and proprietary wireless technologies.
LAST-MILE HIGH-SPEED INTERNET ACCESS OR WIRELESS DSL
Small and Medium-sized Businesses
This market segment is very often underserved in areas other than the highly competitive urban environments. For many small businesses that are out of reach of DSL or not part of the residential cable infrastructure, IEEE 802.16 represents an easy, affordable way to get connected to broadband. The WiMAX technology can cost-effectively meet the requirements of small- and medium-sized businesses in low-density environments and can also provide a cost-effective alternative in urban areas competing with DSL and leased-line services.
Residential and SoHo High-speed Internet Access
A low-cost alternative could end the war between the cable and ADSL operators and really make the broadband home revolution happen (Figure 5.4). Today this market segment is primarily dependent on the availability of DSL or cable. In some areas the available services may not
Figure 5.4 Enterprise connectivity
meet customer expectations for performance or reliability and/or are too expensive. In many rural areas residential customers are limited to low-speed dial-up services. In developing countries there are many regions with no available means of Internet access. The analysis will show that the WiMAX technology will enable an operator to economically address this market segment and have a winning business case under a variety of demographic conditions.
The most lucrative market for the proprietary BWA vendors has been remote regions, especially in developing countries but also in rural areas of the USA, where there is no wired or cellular infrastructure nor the will or cash to invest in building it. The main alternative to BWA in this market is satellite. Still early in its lifecycle - and potentially a powerful technology to integrate with WiMAX - satellite has severe limitations of upstream bandwidth, spectrum availability and also suffers from high latency.
Underserved markets include rural towns, and even newer suburban developments. An underserved area is any place where, for mostly economic reasons, high-speed wireline or wireless infrastructure was never constructed.