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In this paper, we propose a 2 × 2 cooperative multiple-input multiple-output (MIMO) orthogonal frequency-division multiplexing (OFDM) scheme based on Alamouti space-time coding. In this scheme, the the relay and the destination antennas receive the transmitted symbols from the source during the first stage. Then, both the relay and the destination generate their own decision variables using an Alamouti...
The performance of dual-hop Decode-and-Forward relaying with relay selection (RS) and repetitive transmission is studied over Nakagami-m fading channels. Closed-form expressions for the moment generating function of RS-based transmission with maximal-ratio diversity at the destination and repetitive transmission with selection diversity (SD) are derived. We obtain the outage probability (OP) and the...
Spectrally Efficient Frequency Division Multiplexing (SEFDM) system proposes enhanced spectrum utilization in contrast to Orthogonal Frequency Division Multiplexing system (OFDM). Spectral efficiency is increased by relaxing the orthogonality condition while maintaining the same transmission rate per individual channel, hence, for the same bandwidth allocation SEFDM offers higher throughput than OFDM...
In this paper, we presents a new nonlinear iterative learning control law for a class of nonlinear systems, denoted NP-D-INP-D, which is composed by limiting the action of error in PID learning law, that is, use a bounded nonlinear function of error instead of error, and adding a differential feedback in the integrator of PID learning law to inject the suited damping. By using Bellman-Gronwall lemma,...
In this paper a modified Offset Min-Sum decoding algorithm for Low-Density Parity Check Codes is presented. In this modified algorithm, the offset factor in the original Offset Min-Sum algorithm is adjusted iteratively with the assistance of the check-node computation outputs of the Normalized Min-Sum algorithm. As a result, the offset factor in our modified algorithm can be calculated adaptively...
According to the defects of the XCTD (Expendable Conductivity, Temperature, and Depth) Profiler low data transmission rate and reliability, a modem underwater data transmission system is introduced. The absolute phase-shift demodulated signal of the phase ambiguity problem is overcome by π/4-QDPSK, which is a linear narrow-band digital modulation technique and has high bandwidth efficiency, low bit...
Adapting resource management, for vague environments, in wireless communication proved to be a measure point of research recently. In this paper we present a system that is capable of adapting some important resources (type of modulation, code rate and number of subcarriers) for blurred channel conditions. The system in this work is mainly designed for WiMAX, which proved to be one of the prominent...
Adaptive HF OFDM system can improve the transmission performance by bit and power loading based on the characteristic of subchannel. Greedy algorithm is the optimal method for finite granularity bit allocation, but it has high computational complexity. A new improved bit and power loading algorithm is proposed for HF OFDM systems in this paper, some bits is pre-allocated to some subchannels based...
Fiber-optic dispersion and its effect on optical transmission system are analyzed. The most commonly used dispersion compensation fiber (DCF) technology is studied in this article. Three schemes (pre-compensation, post-compensation, mix-compensation of dispersion compensation) of dispersion compensation with DCF are proposed. The simulation model of the WDM based on the Optisystem is presented according...
Multi-carrier code division multiple access (MCCDMA) is an attractive choice for high speed wireless communication as it mitigates the problem of inter symbol interference (ISI) and also exploits frequency diversity. In order to support multiple users with high speed data communications, the MC-CDMA technique is used to address these challenges. In this paper working of Transmitter and Receiver model...
The effect of body movement on performance of body area communication system was studied. Channel gains on body standing, walking, and running were measured in experiments. Based on the experiments' data, channel gain obeyed normal distribution. Parameters were estimated using maximum likelihood method. Then, channel statistical and simulation model has been established to analyze the system performance...
Total robustness to illumination change is difficult to solve just using a single approach. Our approach to improvement in accuracy and robustness to illumination change is by fusing two different methods, namely, color constancy and color co-occurrence. A “grey world” assumption is used to handle sudden illumination change while color cooccurrence modelling is used to handle gradual illumination...
In this paper, we introduce a kind of high performance of concatenated code that is called parallel concatenated code. Comparing to conventional serial concatenated code, it has more matching room and higher adaptability. Moreover, burst of errors which are aroused by noise are beautiful restrained. For certifying the superiority and practicability, we research a parallel concatenated code by combining...
The standard transmission control protocol(TCP) can not distinguish between the random packet losses due to high bit error rate(BER) and the packet losses due to network congestion. TCP responds to all losses by invoking congestion control and avoidance algorithms, resulting in degraded end-to-end performance in wireless and lossy systems. Meanwhile, the performance of TCP would be deteriorated very...
Nonlinear receiver architectures employing a limiting amplifier for analog-to-digital conversion are often applied in low-power wireless communications to reduce hardware complexity and power consumption. These advantages come at the cost of a degradation in performance compared to their linear counterparts. This work presents the optimum receiver for 1-bit quantized signals and provides the analytical...
In this paper, we investigate a dual-hop decode-and-forward opportunistic relaying scheme where the source may or may not be able to communicate directly with the destination. In our study, we consider a regenerative relaying scheme in which the decision to cooperate takes into account the effect of the possible erroneously detected and transmitted data at the best relay. We derive an exact closed-form...
In this paper we consider an SC-FDE (Single Carrier Frequency-Domain Equalization) block transmission with residual frequency errors. We employ a frequency-domain iterative DFE (Decision Feedback Equalization) denoted by Iterative Block-Decision Frequency Equalization (IB-DFE), which is combined with a Decision-directed (DD) Carrier Frequency Offset (CFO) estimator. This estimator produces a CFO estimate...
In this paper, we present a new robust scheme for use in asynchronous cooperative networks over frequency-selective channels through using three and four relay nodes. Based on extended orthogonal space-time block coding (EO-STBC), we have presented a direct quantized feedback approach that can achieve full cooperative diversity and array gain with unity code rate over each hop. In this scheme, we...
In this paper, we present and analyze a rate-adaptive multiuser orthogonal random beamforming (ORBF) system. The goal is to maximize the average spectral efficiency (ASE) while satisfying a target bit error ratio (BER) constraint. We first derive the cumulative distribution function of the post-scheduling signal-to-interference-plus-noise ratio (SINR) with a new approach. The average BER and the ASE...
We consider in this paper the problem of blind frame synchronization of systems using Reed-Solomon (RS) codes and other related families. We present first of all three techniques of blind frame synchronization based on the non-binary parity check matrix of RS codes. While the first two techniques involve the calculation of hard and soft values of the syndrome elements respectively, the third one perform...
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