Performance Evaluation For Detection Of White Spaces In Cognitive-Ofdm Based Wireless Communications Networks

摘要

The radio electromagnetic spectrum is limited source for many wireless communication devices.many studies on wireless communication show that a large portion of our radio electromagnetic spectrum remains vacant all time .How this radio electromagnetic spectrum can be utilized more . cognitive radio is a solution to this problem. The cognitive radio, based on a software-defined radio. Cognitive radio is an advanced and intelligent wireless communication system that is aware of its environment and uses the methodology of understanding- by-building to learn from the environment and adapt to statistical variations in the input stimuli, with two primary objectives in mind:. there should be always highly reliability in communication network . . there should be proper utilization of the radio spectrum. Many research has proved that orthogonal frequency division multiplexing system (OFDM) has been proposed as a main candidate for cr's physical layer. Additionally, performance of a wide band spectrum analysis can be supported by Fast Fourier Transform (FFT) in an OFDM receiver. Multitaper spectrum estimation method (MTM) is a non-coherent promising spectrum sensing technique. It has solved the problems of bad biasing and large variance in power spectrum estimation .Biasing and Variance are two important parameters to calculate performance evaluation of any power spectrum estimation method