Optical Orthogonal frequency division multiplexing (OOFDM) is shown to outperform RZ-OOK transmission in high-speed optical communications systems in terms of transmission distance and spectral efficiency. The OOFDM in combination with the subcarrier multiplexing offers a significant improvement in spectral efficiency of at least 2.9 bits/s/Hz.

Channel estimation is the key technology for Orthogonal Frequency Division Multiplexing (OFDM), which has direct impact on the performance of OFDM. In this paper, we present a novel QRbased algorithm to update the channel impulse response (CIR) for DFT-based channel estimation. The discrete Fourier transform (DFT) estimation reduces the noise power that exists outside of the CIR part, because t...

The main objective of this project is to design the full-rate Space-Time-Frequency Trellis code (STFTC), which is based on Quasi-Orthogonal designs for Multiple-Input Multiple-Output (MIMO) Orthogonal Frequency Division Multiplexing (OFDM) systems. The proposed Quasi-Orthogonal Space-TimeFrequency Trellis code combines set partitioning and the structure of quasi-orthogonal space-frequency desig...

Visible light communication (VLC) system for small range transmission uses visible spectrum which provides illumination simultaneously. Designing cost of light emitting diodes was reduced in order to make this communication possible. A modulation technique which can effectively employ the bandwidth is orthogonal frequency division multiplexing (OFDM) technique. This technique has a unique form ...

Abstract -Orthogonal frequency division multiplexing is a scheme of encoding digital information on numerous carrier frequencies. The orthogonality permits an proficient modulator and demodulator realization by means of FFT algorithm resting on receiver side, and inverse FFT resting on sender side. A substitute technique for orthogonal transmission and reception of data using Rajan Transform an...

Multiple input multiple output-orthogonal frequency division multiplexing-code division multiplexing (MIMO-OFDM-CDM) techniques are considered to improve the link reliability/spectral efficiency of very high data rate communication systems. In particular, lattice-reduction-aided receivers are proposed for MIMO-OFDM-CDM systems. Simulation results show that the proposed receivers significantly o...

In this paper, an OFDM-CDM (orthogonal frequency division multiplexing code division multiplexing) system with adaptive symbol mapping is presented. This combination enables a robust transmission with flexible error protection and data rate adaptation for parallel data streams by exploiting additional diversity due to CDM. Performance results are presented for fading channels where OFDMCDM with...

This paper proposes a efficient blind sampling frequency offset (SFO) estimation technique for an orthogonal frequency division multiplexing (OFDM) based power line communication (PLC) system. The main drawback of the conventional estimators is their limited estimation range and their high sensitivity to effect of SFO. To remedy these, this paper proposes two-step correlation scheme that exploi...

The multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) system with space-frequency block coding (SFBC) is an attractive technique due to its robustness for time selective fading channels. SFBC MIMO-OFDM systems have a high computational complexity since the number of inverse fast Fourier transforms (IFFTs) required scales in direct proportion to the number o...