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ess, they must look for ways to lower operating costs. Backhaul costs for cellular operators represent a considerable portion of their recurring costs. WiMAX can provide Point-to-Point links of up to 30 miles (50 km), with data rates capable of supporting multiple E1/T1s. WiMAX equipment can thus be used by cellular operators for backhauling Base Station traffic to their Network Operation and Switching Centers, as shown in figure 3.3..

The built-in QoS attribute of WiMAX is highly suitable for cellular traffic which is a mix of voice and data. Backhaul facilities leased from local telephone companies can be too expensive, and installing a fiber solution, can be both costly and prolonged. For providing cellular backhaul, wired solutions are not often cost-effective in rural or suburban areas, and most versions of DSL and cable technology cannot present the requisite bandwidth, particularly for backhauling 3G networks.

3.7.1.2 Wireless service provider backhaul
WiMAX equipment is used by wireless Service Providers (WSPs) for backhauling traffic from BS in their access networks, as shown in figure 3.4.

WiFi, WiMAX or some proprietary wireless access technology might be used as an access network. As WSPs normally proffer voice, data and video, the WiMAX built-in QoS attribute will assist in prioritizing and optimizing the backhauled traffic. The working expenditure are raised for hiring backhaul services from the local telephone company, and deploying a fiber network can be incredibly expensive and entails considerable long time. Moreover, in rustic and suburban areas, fiber, DSL and cables are not money-making, and the capacity necessary for these networks might not be offered by DSL and cable technologies.

3.7.1.3 Banking networks
The branches and ATM sites of large banks carrying voice, data and video traffic can be connected to their regional office through a private WiMAX network as shown in figure 3.5. These banks require high safety and bandwidth to manage the traffic as they are usually spread over a large area.

To defend against undesired interruption and management of sensitive banking traffic WiMAX data encryption offers superb link security. Due to large coverage and high capacity, a huge no: of diversely situated branch offices and ATM sites can be linked to the bank's regional office.

3.7.1.4 Education networks
School board office can connect the schools with their office by making use of Private WiMAX network as shown in figure 3.6.

Using QoS, the complete range of communication necessities, comprising telephony voice, operating data (for example records of students), email, Internet and intranet access (data), and distance education (video) can be delivered by the education networks based on WiMAX, among the school board office and all of the schools in the range, and among the schools themselves [26].

3.7.2 Public networks
In public network, resources are accessed and shared by both businesses and private individuals. In Public networks the users position is neither predictable nor static so they usually need a cost-effective means of providing ever-present coverage. Voice and data communication are the major applications of public networks, while video communication is becoming more and more popular. As several users share the network, security is a critical requirement. These con