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Orthogonal Frequency Division Multiplexing (OFDM) is designed to improve the spectral efficiency and combat multipath fading by dividing the wide band frequency selective fading channel into many narrow flat sub-channels. The noise in the wireless communication channel may damage the OFDM transmission signal and reduce the signal-to-noise ratio (SNR) at the receiver, which limits the bit error rate...
The inter-carrier interference (ICI) caused by Doppler spread in mobile channels affects the OFDM orthogonality. This paper presents a comparative study of the performance of different low complexity methods to estimate the ICI power present in mobile reception. In addition, a new method based on experimental results is proposed. Several computer simulations based on OFDM systems with Log-likelihood...
In this paper, we theoretically investigate the effects of noise and nonlinear distortion on the performance of orthogonal frequency-division multiplexing (OFDM) signal carried by millimeter-wave radio over fiber (RoF) systems. Various noise components are considered in this paper including shot noise, thermal noise and relative intensity noise. In addition, we take into account the effect of nonlinear...
In recent years, communications systems through mains, known as PLC (Powerline Communication), have received a lot of interest as part of intelligent networks or smart grids, as well as for multimedia applications at homes. In broadband PLC, systems using multicarrier modulations allow the mitigation of selective frequency fading in the channel. Nevertheless, these modulations require accurate time...
Various computer simulations are used to illustrate the performance of a particular protocol. However, the number of parameters and logical layers considered is the key to getting accurate results. We extend our previous work of Complete Transmission Acknowledgement Scheme (CTAS) by running the proposed model on top of the physical layer. Effect of noise and the standard Orthogonal Frequency Division...
The spectrum sharing between radars and communication networks raises attention in recent years. Unlike communication, the radars usually occupy large extent of frequency bandwidth, and have different kinds of missions, which make the spectrum sharing problem more complicated. In this paper, we model the scenario that multiple imaging radars, which are the most common spectrum demanders, working in...
In this paper, a low overhead preamble structure is proposed for the interference approximation method — complex (IAM-C) method in offset quadrature amplitude modulation based orthogonal frequency division multiplexing (OQAM-OFDM) systems. Compared with the conventional preamble structure with three columns of symbols, the proposed preamble structure only requires two columns of symbols as the preamble...
A novel noise whitening technique of blind subspace channel estimations is proposed for cyclic prefixing multiple-input multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) systems. A fast convergence subspace channel estimation for cyclic prefixed MIMO-OFDM systems was presented in [1] where the repetition index was used to increase the number of equivalent received signals. However,...
We present the first measurement of PMD mitigation in Stokes vector direct detection (SV-DD) systems. By applying two novel algorithms, PMD tolerance has been improved from 3.5 to 9 ps for a 93-Gb/s SV-DD system.
This paper reports a demonstration of high speed visible light communications using a blue laser diode combined with a remote phosphor. This method both generates white light and supports multi Gb/s communications. Data rates of up to 5.62 Gb/s and 6.52 Gb/s were achieved by using OFDM with fixed-rate and adaptive loading approaches, respectively. A total data rate of 10 Gb/s was found to be achievable...
The development of next-generation networks has been driven by a number of use cases aimed at supporting innovative applications and services. Among these drivers the Internet of Things has gained momentum due to its potential to leverage Machine Type Communications (MTC), a term used to denote machine-centered communications among sporadic, bursty traffic generating devices. While scalability issues...
With the rapid spread of the light emitting diode (LED), visible light communication (VLC) is becoming an emerging wireless communication technology. VLC offers advantageous properties such as safety, environmental protection, worldwide availability and high capacity. It can be used as an effective supplement of the existing wireless communication. Power line communication (PLC) using the omnipresent...
The problem of bit and power loading for bit rate maximization in OFDM data communications over indoor powerline channels is investigated and a simple method for bit/power allocation in a single cycle of the mains is developed. The proposed solution is based on the so called Zadeh's representation for modelling the linear periodically time-varying behavior of powerline channels. Numerical results...
Many acoustic channels suffer from interference which is neither narrowband nor impulsive. This relatively long duration partial band interference can be particularly detrimental to system performance. In operational networks, many “dropped” messages are lost due to partial band interference which corrupts different portions of the received signal depending on the relative position of the interferers,...
This paper presents a widely linear equalizer in single carrier systems with frequency-domain equalization (SC-FDE) for underwater acoustic communications. The usage of this equalizer instead of its common strictly linear counterpart allows the distance between transmitter and receiver for a given transmitted power to be increased while maintaining the same bit error performance in a variety of scenarios.
This work proposes a sensor network using the power line communication (PLC) technique in master-slave sensor/control network applications especially using in DC power systems. In the accustomed microcontroller-based master-slave sensor/control network are designed by the serial communication topology and communicates with a controller and coupled the signals with modems in the both ends used the...
Free space optical (FSO) communication systems with its high data rate, capacity same as optical fiber and secure communication over unlicensed spectrum have become a promising technology where the installation of optical fiber is not possible. However, bit-error-rate (BER) performance of FSO link depends on the atmospheric conditions and turbulence strength. In this paper, the performance of intensity...
Power-line communications (PLC) commonly employs orthogonal frequency-division multiplexing (OFDM) as the modulation technique, and impulsive noise has a significant negative impact on its performance. Using the property of null subcarriers in OFDM and the fact that impulsive noise is sparse, we formulate a minimization problem to detect and estimate the impulsive noise. In previous works, ℓ1-norm...
In this paper, we consider the problem of channel and phase noise estimation for an orthogonal frequency division multiplexing (OFDM) radio link. We solve this problem by first investigating the subspace in which the phase noise spectral vector lies and then exploiting this information during estimation. Building upon earlier works, the phase noise spectral estimate is obtained by minimizing a homogeneous...
Frequency domain equalizers (FEQs) have been applied extensively in multicarrier systems to enhance transmission rate by reducing transmit redundancy in the form of guard interval. The proposed equalization algorithm is able to remove intersymbol and intercarrier interference (ISI and ICI) incurred by the reduction or the absence of this redundancy by properly exploiting null subcarriers that are...
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