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In this paper, we present an amplify and forward based dual-hop free space optical communication (FSO) system with a radio frequency (RF) backup link. In which, the dual-hop FSO links are modeled by log-normal distribution turbulence, and the RF link is assumed to follow the Rayleigh distribution. For the proposed system, analytical expressions for the cumulative distribution function and the probability...
In this paper, discrete-rate adaptive modulation using variable switching thresholds for amplify-and-forward cooperative systems is evaluated over Rayleigh fading channels. The aim is to improve spectral efficiency of cooperative transmission by maintaining the error rate at acceptable level. The switching thresholds are adjusted using a simple algorithm which depends only on the detection of error...
In this paper, we design a distributed relay selection strategy to achieve equal power consumption for all available relay nodes in AF cooperative system. This strategy gives a closed-form expression for the weight coefficient introduced to achieve the required fairness. It aims to reduce the complexity of the conventional centralized strategy that also tries to divide the total consumed power equally...
In this paper, we propose a decode-and-forward incremental relaying scheme to improve the performance of wireless communication systems. In specific, the scheme aims to enhance the spectral efficiency by introducing a policy that avoids cooperative transmission whenever it is not beneficial. We provide performance analysis in terms of average spectral efficiency and average bit error rate under Rayleigh...
In this paper, we introduce an adaptive cooperative system that selects the best relay among the available relay nodes to cooperate with a source node for transmitting the information signal to a destination node if the spectral efficiency can be maximized. This maximization is achieved as long as the average bit error rate is below a target level. The channels are modeled as independent and identically...
In this paper, we consider how to improve the capacity of wireless communication networks that employ cooperative diversity techniques. For Amplify and Forward (AF) fixed relaying scheme with adaptive modulation, it has been shown that the scheme can increase transmit diversity but with the expense of a reduction in the spectral efficiency. An efficient Generalized Switching Policy (GSP) for AF incremental...
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