Closed form expression for the inverse cumulative distribution function of Nakagami distribution

Wireless Networks - Quantile function or inverse cumulative distribution function (CDF) is heavily utilized in modelling, simulation, reliability analysis and random number generation. The use is...     

New closed-form expressions for SNR estimates of Nakagami fading channels by the method of moments

Method of moments has been a parameter estimation technique appropriate to calculate signal-to-noise ratio (SNR) estimates in fading channel models in which an optimal technique like maximum likelihood estimation is not mathematically tractable. In this article, the ratio of the second moment squared to the fourth moment of the received signal envelope is considered to calculate an exact expression for the SNR estimate in Nakagami-m fading channel for M-QAM and \(\theta \)-MQAM modulations as well as expressions to evaluate the variance and the mean of the estimate. The paper presents two useful contributions for SNR estimation theory on Nakagami fading. Besides the exact algebraic expression for the estimate for a generalized QAM modulation scheme, its performance is evaluated through a statistical linearization argument.     

Approximation of envelope statistics with Nakagami distribution foroutput of noncoherent diversity combiners

A simple relationship for estimating the fading parameter m of the Nakagami distribution is obtained for the output of L-branch noncoherent diversity combiners when the branch signals of unequal mean powers are independently Rayleigh faded. Comparisons between the exact distributions and the Nakagami distribution with approximated ms for L=2 and L=3 show good agreement over wide ranges of relative mean powers between the branch signals     

Sum and difference of two squared correlated Nakagami variates in connection with the McKay distribution

General formulas for the probability density function of the sum and the difference of two correlated, not necessarily identically distributed, squared Nakagami variates (or equivalently, gamma variates) are derived. These expressions are shown to be in the form of the McKay "Bessel function" distributions. In addition, formulas for the moments of these distributions, in terms of the Gauss hypergeometric function, are provided. An application of these new results relevant to the calculation of outage probability in the presence of self-interference is discussed.     

Exact BER analyses of Nakagami/Nakagami CCI BPSK and Nakagami/Rayleigh CCI QPSK systems in slow fading

A recent letter presented an approximate bit error rate (BER) analysis of coherent binary phase-shift keying (BPSK) in cochannel interference with Nakagami faded desired and interfering signals. Here, the exact BER of coherent nonreturn-to-zero (NRZ) BPSK with cochannel interference in Nakagami fading is derived showing that the approximate analysis may be inaccurate. The exact BER of NRZ quaternary PSK (QPSK) with Nakagami faded desired user signal and Rayleigh faded interfering signals is also derived. Slow fading, asynchronous timing and independent fading gains are assumed.     

Nature inspired meta‐heuristic algorithms for solving the service composition problem in the cloud environments

Many sorts of services in the cloud environments must be composited based on the user's requests to meet the requirements. Thus, the distributed services are joined to the cloud services through service composition. Also, it is known as NP‐hard problems and many researchers significantly are focused on this problem in recent years. Therefore, many different nature‐inspired meta‐heuristic techniques are proposed for solving this problem. The nature‐inspired meta‐heuristic techniques have an important role in solving the service composition problem in the cloud environments, but there is not a wide‐ranging and detailed paper about reviewing and studying the important mechanisms in this field. Therefore, this study presents a comprehensive analysis of the nature‐inspired meta‐heuristic techniques for the service composition issue in the cloud computing. The review also contains a classification of the important techniques. These classifications include Ant Colony Optimization, Bee Colony Optimization, Genetic Algorithm, Particle Swarm Optimization, Cuckoo Optimization Algorithm, Bat Algorithm, greedy algorithm, and hybrid algorithm. An important aim of this paper is to highlight the emphasis on the optimization algorithms, and the benefits to tackle the challenges are encountered in the cloud service composition. Also, this paper presents the advantages and disadvantages of the nature‐inspired meta‐heuristic algorithms for solving the service composition problem in the cloud environments. Moreover, this paper aims to provide more efficient service composition algorithms in the future. Finally, the obtained results have shown that the discussed algorithms have an important effect in solving the cloud service composition problem, and this effect has been increased in recent years.     

Nature inspired discrete firefly algorithm for optimal mobile data gathering in wireless sensor networks

Nowadays wireless sensor networks enhance the life of human beings by helping them through several applications like precision agriculture, health monitoring, landslide detection, pollution control, etc. The built-in sensors on a sensor node are used to measure the various events like temperature, vibration, gas emission, etc., in the remotely deployed unmanned environment. The limited energy constraint of the sensor node causes a huge impact on the lifetime of the deployed network. The data transmitted by each sensor node cause significant energy consumption and it has to be efficiently used to improve the lifetime of the network. The energy consumption can be reduced significantly by incorporating mobility on a sink node. Thus the mobile data gathering can result in reduced energy consumption among all sensor nodes while transmitting their data. A special mobile sink node named as the mobile data transporter (MDT) is introduced in this paper to collect the information from the sensor nodes by visiting each of them and finally it sends them to the base station. The Data collection by the MDT is formulated as a discrete optimization problem which is termed as a data gathering tour problem. To reduce the distance traveled by the MDT during its tour, a nature-inspired heuristic discrete firefly algorithm is proposed in this paper to optimally collect the data from the sensor nodes. The proposed algorithm computes an optimal order to visit the sensor nodes by the MDT to collect their data with minimal travel distance. The proposed algorithm is compared with tree-based data collection approaches and ant colony optimization approach. The results demonstrate that the proposed algorithm outperform other approaches minimizing the tour length under different scenarios.     

Maximum-likelihood based estimation of the Nakagami m parameter

Maximum-likelihood estimation of the Nakagami (1960) m parameter is considered. Two new estimators are proposed and examined. The sample mean and the sample variance of the new estimators are compared with the best reported estimator. The new estimators offer superior performance.     

PowerAntz: Ant behavior inspired power budget distribution scheme for Network-on-Chip systems

In Network-on-Chip (NoC) based complex system design on-chip power management is a challenging issue. Most power management schemes fail to provide optimal power sharing among on-chip routers when the power budget distribution varies significantly due to their non-uniform placement on chip. This paper presents PowerAntz, an ant system inspired distributed power management strategy for NoC based systems. This is an adaptive and distributed approach to power sharing across routers of a large network on chip and it is shown to be a scalable solution. A detailed flit accurate simulator was developed in SystemC to evaluate the efficiency of the technique. The experiments demonstrate PowerAntz to be up to 30% more effective in distributing power budget compared to existing strategies. Further, it also achieves up to 21.25% improvement in power budget utilization while keeping the energy overhead negligible for best case scenarios.     

空时码在Nakagami衰落信道下性能分析

基于Alamouti提出的BPSK调制下空时分组码在Rayleigh衰落信道中的简单分集方案。推导出多发射和多接收天线系统中正交空时分组码在Nakagami衰落信道的BPSK调制下的比特差错率的最小距离球界,并推广到在高阶调制下衰落信道中系统符号差错率的性能。仿真分析和比较了空时分组码的多天线系统中发射和接收天线分集增益,以及信道相关参数的变化对系统误比特性能的影响。     

Generalized moment estimators for the Nakagami fading parameter

Moment-based estimation of the Nakagami-m fading parameter is studied. A family of new, generalized, estimators, based on real (integer and possibly noninteger) sample moments, is derived. A new integer-moment estimator that outperforms known integer-moment estimators is presented. The new moment-based estimators are asymptotically unbiased and efficient     

Finite-State Markov Chain Models for the Intensity of Nakagami Fading

For the design, analysis, and simulation of communication systems with Nakagami-m fading channels, it is very convenient to model the fading by finite-state Markov chains in which the states represent fade levels or signal-to-noise ratios in decibels. Our approach to the development of such Markov chain models is to work with the intensity of the fading process, which is proportional to the logarithm of squared envelope of the faded signal. We demonstrate that all the parameters of the Markov chains can be determined from the bivariate distribution of the intensity of the Nakagami-m fading process. Several analytical results are derived from the bivariate distribution of the intensity, including expressions for the chain’s transition probabilities for both adjacent and nonadjacent states and the asymptotic distribution of the intensity for deep fades. For several values of m, we verify the accuracy of our Markov chain models as simulation tools by comparisons of the state probabilities and level-crossing rates obtained from simulations of the Markov chain with those obtained from our analytical expressions.     

Nakagami信道的中断容量分析

本文讨论了Nakagami-m衰落信道系统的中断容量性能,在发射端未知信道信息,接收端的信道估计存在误差时,给出了计算中断容量上界和下界的表达式,它们是接收端的估计误差和信道参数的函数,仿真结果表明随着估计误差的增大中断容量的上界和下界同时降低,但是中断容量的下界随着信道参数的增大而增大,上界随着信道参数的增大而减小。     

Error rate of asynchronous DS-CDMA in Nakagami fading

An accurate bit-error-rate (BER) calculation method is derived for a binary direct-sequence (DS) spread-spectrum multiple-access (SSMA) system using conventional matched filter receivers and random sequences on flat-fading Nakagami channels. A closed-form expression for the characteristic function of a sum of multiple Nakagami interfering signals is found. The accuracy of the standard Gaussian approximation (SGA) is assessed for DS code-division multiple-access (CDMA) systems operating on Nakagami fading channels.     

Effects of Nakagami fading on antijam performance requirements

The effect of fading on antijam (AJ) performance is considered when the envelopes of both the desired signal and the jamming signal fade with a Nakagami distribution. Two cases are analysed for conventional systems. In the first case, the fading is assumed to be slow compared with the duration of the message. In the second case, the fading is assumed to be slow compared with the symbol duration but fast compared with the message duration. For both cases numerical results are also included     

General Nakagami approximation for sum of Ricean interferers

The statistical distribution of the sum of interfering signals at the receiving end of a wireless system is important to effect theoretical evaluation of its performances. The authors show that the sum of generic, narrow-band, Ricean interferers can be approximated by a single Nakagami interferer. A theoretical insight about this fact is given and some simulated results are shown to confirm the result     

Analysis of selection diversity on Nakagami fading channels

A theoretical framework to evaluate the performance of different pre-detection diversity techniques in various mobile radio environments is developed     

Nakagami衰落信道中差分空时分组码误比特率分析

研究差分空时分组码在Nakagami衰落信道下的性能.在介绍2发1收差分空时分组码编译码方案的基础上,得出Nakagami信道下差分空时分组码的误比特率.仿真结果与理论计算值一致,证明了所推导误比特率计算表达式的正确性.     

On the Simulation and Correlation Properties of Phase-Envelope Nakagami Fading Processes

The aim of this Letter is twofold: to propose a simulator for both the phase and the envelope of Nakagami fading channels with arbitrary parameters and to derive precise closed-form approximations to the correlation functions of the Nakagami envelope, phase, and quadrature components.