This paper proposed a new OFDM scheme called damped zero-pseudorandom noise orthogonal frequency division multiplexing (DZPN-OFDM) scheme. In the scheme, ZPN-OFDM non-zero part to reduce guard interval energy as well mutual interference power in-between data and training blocks, conservative pseudo-noise conventional properties required for channel estimation or synchronization. The motivation ...

Orthogonal frequency division multiplexing (OFDM) is a promising technique for high-data-rate wireless communications because it can combat inter-symbol interference (ISI) caused by the dispersive fading of wireless channels. The proposed research focuses on techniques that improve the performance of OFDM based wireless communications and its commercial and military applications. In particular,...

Introduction: Orthogonal-frequency-division-multiplexing (OFDM) is a special form of multicarrier modulation where a single data stream is transmitted over a number of lower rate orthogonal subcarriers [1]. Such a format has been widely implemented in various digital communication standards. Recently we proposed an equivalent optical multicarrier modulation format, called coherent optical OFDM ...

Abstract High speed and low latency have become the development trend of mobile communication network. Orthogonal frequency division multiplexing (OFDM) technology has key network due to its efficient transmission method. Space time block coding (STBC) introduces space correlation in signals sent by different antennas, so that diversity gains are obtained for multiple input output-OFDM (MIMO-OF...

In Orthogonal Frequency Division Multiplexing (OFDM) systems, the cyclic-delay diversity (CDD)Scheme is a low-complexity means of increasing transmit diversity. Because it requires only one inverse discrete Fourier transform (IDFT) operation at the transmitter. The mean square error (MSE) of both the least square (LS) channel estimate and the minimum mean square error (MMSE) channel estimate ar...

OFDM and its extension Multi-band OFDM (MB-OFDM) are considered as the modulation schemes for many future communications systems. But these schemes cause high PAPR which should be reduced before power amplification otherwise non-linearities can occur. In this paper Tone Reservation method is used for OFDM PAPR reduction where a corrective signal is added to the original signal to reduce its PAP...

Orthogonal frequency-division multiplexing (OFDM) with multiple transmit and multiple receive antennas (MIMO-OFDM) is considered a candidate for high-data rate communication in various existing and forthcoming system standards. To achieve the usually desired low frame and bit error rates, MIMO-OFDM should be combined with adaptive bit loading (ABL) and forward error correction (FEC) coding, whe...

We present the performance of OFDM systems with coding, spreading, and clipping. Low-Density Parity-Check (LDPC) codes give coding gains and spreading by the Walsh Hadamard transform gives gains in terms of increased frequency diversity as well as reduced peak-toaverage power ratio (PAPR) of the transmitted OFDM signal. By evaluating both the IFFT transform (OFDM) and the Walsh Hadamard transfo...

This paper compares the performance of a Turbo coded OFDM wireless link for SISO, SIMO, MISO and MIMO system with uncoded OFDM wireless link for SISO, SIMO, MISO and MIMO system in the in the presence of rayleigh fading. Turbo encoder encodes the input information bits and sends to QPSK or 16 QAM or 64 QAM modulator. Modulated symbols are mapped by STBC. Outputs of STBC are split into n streams...

Recently, the demand of high-speed network in home is increasing. PLC (Power Line Communication) is expected as one method of realizing it. OFDM is one of the methods, which realizes high-speed PLC. But the minimum stopband attenuation of OFDM modulation is only -13dB. It indicates that OFDM subchannels are not spectrally isolated, therefore OFDM is sensitive to the locations of narrow band int...