The destructive impact of fading environments and also bandwidth limitations are two main challenges which communication is dealing with them. These challenges can affect on the growth of wireless communication and even cause reliable communications and high data rate to be prevented. Thus, OFDM (Orthogonal Frequency Division Multiplexing) modulation by using of fast calculation hardwares such ...

Orthogonal Frequency Division Multiplexing (OFDM) has emerged as a promising modulation technique for high speed optical systems as it reduces intersymbol interference and offers high spectral efficiency. But it has an inherent drawback of high Peak to Average Power Ratio (PAPR) due to multiple subcarriers which makes it sensitive to non linear effects. Different techniques have been proposed f...

Orthogonal Frequency Division Multiplexing System (OFDM) suffers from the problem of high peak to average power ratio reduction (PAPR). It is studied that Golay complementary codes (GCC) can provide codewords with low PAPR. However, the usefulness of this coding technique is limited to the OFDM with a small number of subcarriers. With the help of certain theorems and definitions, this paper dis...

High peak-to-average power ratio (PAPR) of the transmitted signal is one of the limitations to employing orthogonal frequency division multiplexing (OFDM) system. This paper considers the use of the tone injection (TI) scheme to reduce the PAPR of an OFDM signal. However, optimal TI (OTI) requires an exhaustive search over all combinations of possible constellations, which is an NP-hard problem...

The main limitation in employing orthogonal frequency division multiplexing (OFDM) system is high peak-toaverage power ratio (PAPR) of the transmitted signal. A new nonlinear companding algorithm that transforms the OFDM signals into the desirable statistics form defined by a linear piecewise function is proposed. The more adjustability in companding form and an effective trade-off between the ...

OFDM is a special kind of Multi Carrier modulation technique which forms the basis for 4G Wireless system. OFDM is a key broadband technology that can supports data rates in excess of 100 Mbps that is essential for next generation 4G broadband communication.. Peak To Average Power ratio is one of the serious problems in OFDM technology that is problem of extreme excursions of transmitted signal...

Peak to average power ratio (PAPR) distribution of the periodic orthogonal frequency division multiplexing (OFDM) symbol sequences is evaluated and it is shown that the OFDM symbol sequence with short period is expected to have high PAPR. PAPR bound of two sequences with Hamming distance D is derived. Using these results, we identify two conditions for the optimal phase sequences of selected ma...

Orthogonal frequency division multiplexing (OFDM) suffers from a high peak to average power ratio (PAPR). Tone reservation (TR) technology is considered as one of the most promising methods because of no additional distortion, no side information, and low implementation cost. However, in all PAPR reduction schemes,determining the optimal target clipping level is difficult. In this paper, we con...

Orthogonal frequency division multiplexing (OFDM) suffers from a high peak to average power ratio (PAPR). Tone reservation (TR) technology is considered as one of the most promising methods because of no additional distortion, no side information, and low implementation cost. However, in all PAPR reduction schemes, determining the optimal target clipping level is difficult. In this paper, we co...

Orthogonal frequency division multiplexing (OFDM) has gained much popularity in the field of wireless communication because of its ability to transfer the data at higher rate, high bandwidth efficiency and its robustness to multipath. Since OFDM has high Peak to Average Power Ratio (PAPR) as major limitation, many techniques were proposed to reduce it. In this paper, a DCT based modified select...