A study of BER Performance of OFDM Modulation in Multi-fading Channel

The diversity and complexity of Multipath fading can influence performance of the Orthogonal Frequency Division Multiplexing (OFDM) modulation. The system performance analysis is based on correct design of a channel model. According to system characters of OFDM, a frequency selective slow fading channel model is built up, by combining the Trapped delay line model and the slow fading characters, such as the Rayleigh, Rician or Nakagami distribution. The theoretical Bit Error Rate (BER) of OFDM system under this channel model is deduced based on the BER or Symbol Error Rate of MQAM under Additive White Gauss Noise (AWGN) channel and the Probability Density (PDF) Function of different slow fading channel. The applicability of this channel model and the System BER performance under different slow fading channel is verified by simulation. The results indicate that the simulation result is consistent with the theoretical analysis under MQAM modulation method, which illustrates that the frequency selective slow fading channel model is suitable for the performance analyzing of OFDM system

Improvement of Fading Channel Modeling Performance for Wireless Channel

Fading channel modeling is generally defined as the variation of the attenuation of a signal with various variables. Time, geographical position, and radio frequency which is included. Fading is often modeled as a random process. Thus, a fading channel is a communication channel that experiences fading. In this paper, the proposed system presents a new design and simulate a wireless channel using Rayleigh channels. Rayleigh channels using two approaches (flat and frequency-selective fading channels) in order to calculate some path space loss efforts and analysis the performance of different wireless fading channel modeling. The results show that the bite error rate (BER) performance is dramatically improved in the value of signal to noise ratio (SNR) is equal to 45dB. Finally, the experimental results show that the proposed method enhances the performance of fading channel modeling by reducing the error of BER when the SNR is reduced also. Moreover, the more accurate model is Rayleigh model which can be considered for developing fading channel model

An improved code rate search scheme for adaptive multicode CDMA

Master'sMASTER OF ENGINEERIN