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When using a high power amplifier(HPA) for high-speed communication, the nonlinear characteristics of the HPA cause power efficiency, bit error rate(BER) performance, and spectral efficiency to deteriorate. Since it is inevitable to use HPA to obtain sufficient transmission power for high-speed communication, it is necessary to compensate for nonlinearity of HPA by using a predistorter. In this paper,...
For the spectrum efficiency improvement of 5G mobile communication, a new waveform based on multi-carrier are important. In this paper, we like to suggest a W-OFDM(weighted orthogonal frequency division multiplex) system design and compare the nonlinear system performance with the already existing OFDM, UFMC(universal filtered multicarrier), FBMC(filter bank multicarrier) systems. At first, we describe...
Recently, it has been studied how to reduce the probability of interception and to increase the efficient security in the wireless digital communication systems. Among the possible approaches for the information security, the chaotic signal can be used to encode information very efficiently in many ways due to the inherent characteristic of irregularity. In this paper, in noise and interference environment,...
Wireless communication and mobile computing devices are using the wildly. These devices basically work in battery power. It is very important to calculate and apply the power consumption and furthermore to develop nice feasible techniques for reducing the power consumption of wireless communication devices. RF and analog parts in the mm-wave and EHF frequency domain typically consume more energy compared...
Inter-carrier interference (ICI) that is generated by carrier frequency offset (CFO) still a problem in based on orthogonal frequency division multiplexing (OFDM) system. To solve that problem, some compensation methods in time domain or frequency domain were studied using matrix. However, most studies need operating inverse matrix, so it spends much run time during equalizing process. And that make...
It is very important to estimate the signal to noise ratio (SNR) of received signal and to transmit the signal effectively for the modern communication system. The performance of existing non-data-aided (NDA) SNR estimation methods are substantially degraded for high level modulation scheme such as M-ary amplitude and phase shift keying (APSK) or quadrature amplitude modulation (QAM). In this paper,...
Studies of low power consumption modulation schemes are based on FSK and PPM. But, these methods require more bandwidth for high data rate transmit. In this paper, we analyse the QAPM modulation for low power consumption and improving bandwidth efficiency modulation method. A QAPM method is an extension of the QAM and the power efficiency of the transmitter is improved by 3dB. In this paper, we compare...
It is very important to reduce PAPR (peak to average power ratio) in the OFDM (orthogonal frequency division multiplexing) communication system. In this paper, we propose an ACE (active constellation extension) method to reduce PAPR without any date rate loss. In this method, the target PAPR is firstly set and then the clipping is used. Next, the active extending is made for the mapping the dispersive...
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