Scalable video transmission using OFDM schemes over wireless channels

Orthogonal Frequency Division Multiplexing (OFDM) is widely used over both wired and wireless channels. OFDM applications rely mainly on its ease of implementation, high data rates, and reduction of fading effects. The paper is concerned with the comparison of FFT and wavelet based OFDM techniques when used to transmit scalable video coded (SVC) signal over wireless channel. The wavelet based system uses Discrete Wavelet Transform (DWT), called here DWT-OFDM. A method is devised to order SVC layers so that the transmission bit rate (bandwidth) of the multiplexed systems can gain further scalability which assist in providing flexible bit rate selection in addition to the scalability in quality of the received video signal. Different bandwidths are considered in transmission of the video signal when transmitted over models of three standard wireless channels. The results have shown that the proposed arrangement of layered scalability for both DWT-OFDM and FFT-OFDM systems can withstand channel fading conditions and bandwidth limitations. FFT-OFDM system performed better than DWT-OFDM over the most transmission scenarios considered here.