MAC protocol for WLAN in Cognitive Radio Envirnment

Abstract

This thesis addresses the intersection of personal wireless technology and computa-tional intelligence. The primary research issue addressed is the organization of radiodomain knowledge into data structures processable in real-time that integrate ma-chine learning and natural language processing technology into software radio. Thethesis denes and develops the cognitive radio architecture. The goal of this thesis isto produce a simulator for cognitive radio environment . The licensed frequency spec-trum is getting lled with customers. If the trend continues, there will soon not beany frequencies left to use for new wireless data transmission applications. However,it has been shown that although many frequencies are bought, in reality they are notall deployed. As an attempt to exploit this, the technique of cognitive radio has beenproposed. Cognitive radios are radio devices that are clever and can listen to thesurrounding. They "sense" for dierent frequency bands and if they nd any thatis unoccupied they adjusts their inner parameters to transmit/receive with this fre-quency. This technique could be used for a wide range of wireless radio applications.This is an open architecture framework for integrating agent-based control, naturallanguage processing, and machine learning technology. A problem is that sometimesa radio device is located in a radio- shadow, for example behind a concrete wall.It will then believe that the shadowed frequency is "free", and hence use that one.What then happens is of course that the device causes interference to the surroundingenvironment. The simulator in this project is built in order to simulate what couldhappen if we just allowed these cognitive users to transmit freely in reality.The main task of the thesis is rstly to develop the simulator and evaluate it withsome realistic values. A new protocol for Cognitive Radio Environment can also beimplemented based on MAC layer.