Saturday, August 11, 2012

IEEE 802.16

The IEEE 802.16 standard delivers performance comparable to traditional cable, DSL, or T1 offerings. The principal advantages of systems based on 802.16 are multifold: faster provisioning of service, even in areas that are hard for wired infrastructure to reach; lower installation cost; and ability to overcome the physical limitations of the traditional wired infrastructure. 802.16 technology provides a flexible, cost-effective, standard-based means of filling gaps in broadband services not envisioned in a wired world. For operators and service providers, systems built upon the 802.16 standard represent an easily deployable “ third pipe ” capable of delivering flexible and affordable last-mile broadband access for millions of subscribers in homes and businesses throughout the world [3, 4] .

The 802.16a is an extension of the 802.16 originally designed for 10 – 66 GHz. It covers frequency bands between 2 and 11 GHz and enables NLOS operation, making it an appropriate technology for last-mile applications where obstacles such as trees and buildings are often present and where base stations may need to be unobtrusively mounted on the roofs of homes or buildings rather than towers on mountains.

The 802.16a has a range of up to 30 miles with a typical cell radius of 4 to 6 miles. Within the typical cell radius NLOS performance and throughputs are optimal. In addition, the 802.16a provides an ideal wireless backhaul technology to connect 802.11 WLAN and commercial 802.11 hotspots with the Internet. Table 5.18 provides a road map of IEEE 802.16 standards.

Applications of the 802.16 are cellular backhaul, broadband on-demand, residential broadband, and best-connected wireless service. The 802.16 delivers high throughput at long ranges with a high spectral efficiency. Dynamic adaptive modulation allows base stations to trade off throughput for range. The 802.16 supports flexible channel bandwidths to accommodate easy cell planning in both licensed and unlicensed spectra worldwide. The 802.16 includes robust security features and QoS needed to support services that require low latency, such as voice and video. The 802.16 voice service can either be TDM voice or VoIP. Privacy and encryption features are also included to support secure transmission and data encryption.

The Worldwide Interoperability for Microaccess, Inc . (WiMAX) forum, an industry group, focused on creating system profi les and conformance programs to ensure operability among devices based on the 802.16 standard from different manufacturers.

Source of Information : Elsevier Wireless Networking Complete

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