Enhancing DVB-H BER based OFDM systems

摘要

Due to the need for enhancing the wireless systems performance, a new technique, and over the last decades, has been imposed to such systems, namely Orthogonal Frequency Division Multiplexing (OFDM). In order to overcome one of the main OFDM drawbacks a new proposal has been investigated, which could limit the usage of such system in the nonlinear devices. Peak-to-Average Power Ratio (PAPR) problem comes as a result of using Fast Fourier Transform (FFT) stage, where the input 2 (N) signals and after the process could be added together in the same phase. In this algorithm some modifications have been made over a previously published, where the wavelet entropy understanding has been imposed to be the judge for the PAPR consideration. In the previous published work, when a wavelet technique was proposed to DeNoise OFDM symbols and Replace the high PAPR and named by DORP. This is attained by making use of an adaptive threshold to allocate the affected samples, which are amended according to the surrounding ones. In the Modified-DORP (M-DORP), the wavelet transform is used to reconstruct the affected OFDM symbol with PAPR based on their entropies. A MATLAB simulation has been made to verify and validate the numerical model that is derived to investigate the systems performance. Furthermore, the achieved results were compared to either our previously published work or to the work that found in the literature. However, the simulation results show BER systems improvement under the same systems' conditions, an additional transceivers complexity has been added. This will leave a space for further improvement in future. Furthermore, the M-DORP gives a noise immunity and verification rate up to 85%.