Enhancing the BER of MIMO-OFDM systems for Speaker verification

Abstract

in this work a new algorithm has been proposed to improve the wireless systems that are compatible with the current new technologies. Therefore, Denoise Orthogonal Frequency Division Multiplexing (OFDM) symbols and Replace the high Peak-to-Average Power Ratio (PAPR); (DORP) has been modified. In DORP, wavelets techniques have been used to denoise the affected OFDM symbol by high PAPR values. After that and based on adaptive threshold method the local maxima and minima will be determined and replaced by the average of them and their surrounding neighbors.The algorithm mainly tackles and overcomes the effect of the high Peak-to-Average Power Ratio problem that is found in OFDM systems, MIMO-OFDM combination has been developed to meet the rapidly increment in the users demand such as the ubiquitous transmission, imposing new multimedia applications and wireless services.A system performance investigation process will be accomplished based on both of numerical method and MATLAB simulation. Moreover, a comparison has been made to check the validity of our proposition either with our previously published work or with the literature. Although, the achieved results show that the proposed work gives an improvement of the BER; an additional complexity has been added to transceiver's structure. Moreover, and as a result to the comparison with the conventional systems, the bit error rate (BER) performance has been improved for the same bandwidth occupancy.As a validity process a comparison has been made with the current values found in the literature and we have achieved around 27% PAPR extra reduction. That is in addition to around 81% verification rate and noise immunity.

Wavelet transform basis to detect the odd peaks in wireless systems

“…Figure 8 shows the BER curves to confirm the reliability of the proposed work for combating the P APR problem. Thus, the performance of the MIMO-OFDM based FFT is still better than either that of the conventional P APR reduction techniques or our previously published work in [8,9]. At 20 dB threshold, the BER curve for the conventional MIMO-OFDM system shows a reduction from 21 xl 0-2 to 12x 10-2 .…”

“…The whole work in this stage could be 3 divided into four blocks as shown in Figure 5. After that, the achieved results will be compared with our previously published work [8,9].…”

“…This equation reflects the disorder degree that the variable acquires. Then, the discrete wavelet decomposition for sampled values of the signal Set) could be written as: (8) The signal Set) is given by the sampled values, e;(k) is the wavelet coefficient and limited to following frequency interval 2 j -1 ws � Iwl � 2 j ws. Moreover, the wavelet entropy could be defmed in terms of wavelet coefficients relative wavelet energy as follows:…”

“…Therefore, the wavelet transform method has been used to tackle the effect of such deficiency as will be discussed in section two [7]. Previously in [8], another proposition of PAPR reduction technique has been addressed based also on wavelet transformation technique. It was based on Denoise the OFDM using some DWT, after that defining an adaptive threshold to limit those peaks, and finally replace these peaks and valleys using an average filter.…”

“…Read a segment of the OFDM signal. [8] In this work, the wireless systems' performance will be drawn for the PD-EWT and compared to the previously published work in [8,9]. This performance will be based on the BER.…”