Error Analysis of Wireless Sensor Network Based on OFDM Signal Transmission Algorithms for Radiation Detection

摘要

Development of wireless sensor network (WSN) for environmental events monitoring through orthogonal frequency division multiplexing (OFDM) signals is the aim of this manuscript. Therefore, the WSN transmission problems through OFDM signals are handled with special emphasis on OFDM signal analysis. The error analysis among sensor nodes (SNs) is addressed. The effects of channel fading on the transmitted OFDM signal among WSNs are analyzed. Closed form expressions for bit error rate (BER) analysis of WSN are proposed under chi-square, Weibul, Gamma and exponential channels fading distribution. Also, the performance of OFDM transmission system that uses high power amplifier (HPA) at transmitter side is analyzed. The generated OFDM signal is modulated using PSK and QAM modulation techniques. The complex wavelet transform (CWT) is applied instead of fast Fourier transform (FFT) for modulation and demodulation purposes of OFDM. Recent interest has focused on high order statistics based algorithms where they are quite robust against channel fading environments. An algorithm that shows the effect of HPA on the modulated signal at the transmitter side is demonstrated. Reduction of high peak to average power ratio (PAPR) of OFDM signal is another challenge problem. Therefore, signal recovery algorithm is conducted in order to overcome such limitation. This algorithm is based on detection of maximum peaks. These peaks are approximated to be equal to the average value of the OFDM signal as well as the detected peaks above the threshold limit of the OFDM signal. A different proposed algorithm using peak and depression method is investigated. Moreover, the obtained results are compared with the general clipping method results. The performance of transmitted OFDM signal over channels fading is evaluated through BER analysis. The obtained result confirms that Rayleigh with Rician channel noise fading introduces the best BER on the transmitted signal. The accuracy of the considered algorithms is evaluated. On other hand, the effect of contaminated channel impairments on the received modulated OFDM signal is investigated. The proposed approach confirms the possibilities of using WSN for signal detection under clutter environments.