Date Added: Apr 2011
Wireless access networks were originally developed for different communication scenarios. Wireless networks aim to provide ubiquitous, flexible communications mainly in community areas. In wireless network, there always exists the need for the communication services at higher data rates and Quality of Service (QoS). Thus lots of different techniques have been explored to improve modern wireless networks to satisfy different requirements and combat different problems. For example, the rapid growth in the ubiquitous wireless services has imposed increasing stress on the fixed and limited radio spectrum. Thus allocating a fixed frequency band to each wireless service, which is the current frequency allocation policies, is a necessary to eliminate interference between different wireless services.