Performance Analysis of OFDM Based Cognitive Radio Network under Channel Uncertainty

Abstract

The main objective of this project is to MIMO is paired up with OFDM to improve the performance of wireless transmission systems. The performance of an OFDM system high. Noise will be reduce high level. Measure the capacity and SNR value. High data rate wireless communication. Multiple antennas are employed both at the transmitting as well as receiving end. The performance of an OFDM system is measured, consider multipath delay spread, channel noise, Rayleigh fading channels and distortion. In this paper, bits are generate and then mapped with modulation schemes such as QPSK. Then, the mapped data is divided into blocks of 120 modulated data where a training sequence of the data is inserted both at the beginning and ending parts of the block. The equalization is used to determine the variation to the rest of data. Therefore, the capacity is increased by transmitting different streams of data through different antennas at a same carrier frequency. Any inter symbol interference (ISI) produced after the transmission is recovered by using spatial sampling integrated with the power allocation. Furthermore, the performance measure by SISO, MIMO, SIMO, MISO using power allocation.TO Calculation of power allocation of OFDM signal using to Calculation of power allocation of OFDM SISO signal, Calculation of power allocation of OFDM MISO signal, Calculation of power allocation of OFDM SIMO signal and Calculation of power allocation of OFDM MIMO signal. The Experimental results show between graphical representing. The compare all graph and plot the Comparison chart.