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The business of wimax - Pareek D.

Pareek D. The business of wimax - Wiley publishing , 2006. - 330 p.
ISBN-10 0-470-02691
Download (direct link): thebusinessof2006.pdf
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The main reason any market remains underserved is because it is difficult to develop a solid business plan for offering services there. Fortunately for all involved, public funding is playing a role in filling that gap.
Topography, bandwidth needs and finances influence whether a community gets broadband service and the best technology to use. Broadband wireless is the pre-eminent solution right now because it is the easiest to deploy and prices have come down.
Broadband on Demand
One aspect of the existing IEEE 802.16a standard that will make it attractive to service providers and end customers alike is its provision for multiple service levels. Thus, for example, the shared data rate of up to 75 mbps that is provided by a single base station can support the ‘committed information rate’ to business customers of a guaranteed
2 mbps (equivalent to a E1), as well as ‘best-effort’ non-guaranteed 128 kbps service to residential customers.
Depending upon regional demand, it should be possible for providers to offer a wide variety of standard and custom service offerings. By providing flexible service and rate structures to its customers, a WiMAX provider can appeal to a wide variety of needs by means of a single distribution point.
The key parameters of WiMAX receiving attention are concerned with its capability to provide differential services. Quality of service enables NLOS operation without severe distortion of the signal from buildings, weather and vehicles. It also supports intelligent prioritization of different forms of traffic according to its urgency.
MAC provide for differentiated QoS to support the different needs of different applications. For instance, voice and video require low latency but tolerate some error rate, while most data applications must be error-free, but can cope with latency. The standard accommodates these different transmissions by using appropriate features in the MAC layer, which is more efficient than doing so in layers of control overlaid on the MAC.
Many systems in the past decade have involved fixed modulation, offering a tradeoff between higher-order modulation for high data rates, but requiring optimal links, or more robust lower orders that will only operate at low data rates.
IEEE 802.16 supports adaptive modulation, balancing different data rates and link quality and adjusting the modulation method almost instantaneously for optimum data transfer and to make most efficient use of bandwidth. For rural areas, where the distances between customers are large, ‘adaptive modulation’ allows it to automatically increase effective range where necessary, at the cost of decreasing throughput. Higher-order modulation (e.g. 64 QAM) provides high throughput at sub-maximum range, while lower-order modulation (e.g. 16 QAM) provides lower throughput at higher range, from the same base station.
The modulation scheme is dynamically assigned by the base station, depending on the distance to the client, as well as weather, signal interference and other transitory factors. This flexibility further enables service providers to tailor the reach of the technology to the needs of individual distribution areas, allowing WiMAX service to be profitable in a wide variety of geographic and demographic areas.
5.3 BACKHAUL Cellular Backhaul
Internet backbone providers in the USA are required to lease lines to third-party service providers, an arrangement that has tended to make wired backhaul relatively affordable. The result is that only about 20 % of cellular towers are backhauled wirelessly in the USA. With the potential removal of the leasing requirement by the FCC, US cellular service providers will also look to wireless backhaul as a more cost-effective alternative. The robust bandwidth of IEEE 802.16 makes it an excellent choice for backhaul for commercial enterprises such as hotspots as well as point-to-point backhaul applications (Figure 5.5). Also, with the WiMAX technology cellular operators will have the opportunity to lessen their independence on backhaul facilities leased from their competitors.
In Europe, where it is less common for local exchange carriers to lease their lines to competitive third parties, service providers need affordable alternatives. Subsequently, wireless backhaul is used in approximately 80 % of European cellular towers. Here the use of point-to-point microwave is more prevalent for mobile backhaul, but WiMAX can
switching office (MTSO)
Figure 5.5 Cellular backhaul
still play a role in enabling mobile operators to cost-effectively increase backhaul capacity using WiMAX as an overlay network. This overlay approach will enable mobile operators to add the capacity required to support the wide range of new mobile services they plan to offer without the risk of disrupting existing services. In many cases this application will be best addressed through the use of IEEE 802.16-based point-to-point links sharing the PMP infrastructure. Some salient points about WiMAX use as cellular backhaul are:
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