Particle swarm optimization–based power allocation for Alamouti amplify and forward relaying protocol

The performance of wireless communication systems is improved over flat fading channel by using Alamouti coding scheme, which provides the quality of diversity gain. In this paper, performance analysis of symbol error rate (SER) and particle swarm optimization (PSO)–based power allocation (PA) for Alamouti amplify and forward (AF) relaying protocol using maximum ratio combining (MRC) technique is presented. Analytical expression of SER upper bound and SER approximation is derived for Alamouti AF relaying protocol with quadrature phase shift keying (QPSK) modulation over Rayleigh fading channel and Rician fading channel. In addition, PSO‐based optimum PA factor is calculated on the basis of the minimum SER of proposed method. PSO‐based optimum PA gives 0.5 dB of improved signal‐to‐noise ratio (SNR) compared with the equal power allocation (EPA). The theoretical approximate SER result is compared with the simulated SER. The proposed protocol provides full diversity gain and reduces SER compared with the existing AF and decode and forward (DF) relaying protocols over Rayleigh fading channel and Rician fading channel.     

Nakagami衰落信道下NNC-DFH接收机抗部分频带干扰性能分析

该文提出了一种噪声归一化合并(NNC)差分跳频(DFH)接收机模型以提高差分跳频系统抗部分频带干扰能力。给出了Nakagami衰落信道下NNC-DFH接收机在部分频带干扰及背景热噪声下误符号率边界的闭式表达式,并采用矩生成函数法进一步求得了衰落指数m为整数时的简化性能边界。仿真结果表明：在非最坏部分频带干扰下,仅在衰落较弱且干扰能量较为分散的特殊情况下,线性合并(LC)DFH接收机性能略优于NNC-DFH接收机,其它情况下NNC-DFH接收机总是优于LC-DFH接收机,且干扰越集中性能优势越显著;在最坏部分频带干扰下,NNC-DFH接收机的抗部分频带干扰性能优于LC-DFH接收机,与信道衰落程度及干扰带宽因子取值无关。     

Performance analysis of L-branch equal gain combiners in equally correlated Rayleigh fading channels

Theoretical performance results for L-branch (L/spl ges/3) coherent equal-gain combining (EGC) in correlated fading channels are not known. This letter develops a novel approach for performance analysis of L-branch EGC in equally correlated Rayleigh fading channels. Such channel gains can be transformed into a set of conditionally independent channel gains. The cumulative distribution function (cdf) of the EGC output signal-to-noise ratio (SNR) is, therefore, derived. The symbol error rate (SER) of different modulation schemes with EGC in equally correlated Rayleigh fading channels is evaluated. Numerical results that illustrate the effects of equally correlated fading on the SER performance of EGC are also provided.     

相关Nakagami衰落信道上DE-QPSK性能分析

推导m为整数的任意相关Nakagami-m衰落信道上采用最大比合并(MRC)分集接收和相干检测的差分编码四相相移键控(DE-QPSK)调制的平均误符号率(SER)精确表达式,并利用高斯Q函数指数形式的近似表达式推导相关Nakagami-m衰落信道上采用MRC分集接收的DE-QPSK调制的平均SER近似表达式。计算机仿真结果验证了精确理论分析的正确性和近似分析的准确性。     

Phase-Jitter based SER of MPSK Scheme over Generalised Mixture Gamma Fading

ABSTRACT

Extensive literature exists for simple and exact expressions of symbol error rate (SER) over fading channels under different modulation schemes whose boundaries meet at right angles. In cases where boundaries do not meet at right angles, integrals of special function in the expressions make the exact calculation most complex. In such cases only approximate solutions are possible. Also, it is noteworthy to mention that when detection is performed with proper use of the phase (phase-jitter-based approach), noise performance of the receiver improves significantly. This paper applies phase-jitter PDF-based approach to present exact and closed-form SER expression of MPSK scheme over Mixture Gamma (MG) distribution for an arbitrary array of signal points. The proposed expression is generic as MG distribution can be approximated in almost all fading/shadowed fading channel models. As a proof to the authenticity, SERs of MPSK scheme over Rayleigh and Nakagami-m fading channels are deduced from the proposed SER over generalised MG distribution. Further, a significant improvement in SER has been achieved with phase-jitter-based approach as compared to conventional (non-phase-jitter-based) approach. Finally, to confirm the correctness of the proposed expression, results are validated through comparison with the existing results and Monte Carlo simulation.     

Error probability of M-ary DPSK in fast Rician fading and lognormalshadowing

A new expression for the symbol error probability (SER) of M-ary DPSK in fast Rician fading, lognormal shadowing and Gaussian noise is derived. New SER curves are computed and the effects of K factor, fading bandwidth and shadowing spread on the error probability are analysed and discussed     

Performance analysis of coherent equal gain combining overNakagami-m fading channels

We study the exact average output signal-to-noise ratio (SNR) and symbol error rate (SER) of M-ary phaseshift-keying (PSK) signals with coherent equal gain combining reception. The analysis assumes independent Nakagami-m (1960) fading paths, which are not necessarily identically distributed. On one hand, we use geometric summations to obtain closed-form expressions for the average output SNR over diversity paths with an exponentially decaying power delay profile. On the other hand, capitalizing on an alternative integral representation of the conditional SER along with Gauss-Hermite quadrature integration, we derive an average SER expression in the form of a single finite-range integral and an integrand composed of tabulated functions. We also present a simpler but approximate approach for the closed-form evaluation of the SER of these signals over independent identically distributed Nakagami-m fading paths     

A unified approach for calculating error rates of linearlymodulated signals over generalized fading channels

We present a unified analytical framework to determine the exact average symbol-error rate (SER) of linearly modulated signals over generalized fading channels. The results are applicable to systems employing coherent demodulation with maximal-ratio combining multichannel reception. The analyses assume independent fading paths, which are not necessarily identically distributed. In all cases, the proposed approach leads to an expression of the average SER involving a single finite-range integral, which can be easily computed numerically. In addition, as special cases, SER expressions for single-channel reception are obtained. These expressions reduce to well-known solutions, give alternative (often simpler) expressions for previous results, or provide new formulas that are either closed-form expressions or simple to compute numerically     

Exact evaluation of maximal-ratio and equal-gain diversityreceivers for M-ary QAM on Nakagami fading channels

Exact integral expressions are derived for calculating the symbol-error rate (SER) of multilevel quadrature amplitude modulation (MQAM) in conjunction with L-fold antenna diversity on arbitrary Nakagami fading channel. Both maximal-ratio combining (MRC) (in independent and correlated fading) and equal-gain combining (EGC) predetection (in independent fading) diversity techniques have been considered. Exact closed-form SER expressions for two restricted Nakagami fading cases (MRC reception) are also derived. An exact analysis of EGC for MQAM has not been reported previously, despite its practical interest. Remarkably, the exact SER integrals can also be replaced by a finite-series approximation formula. A useful procedure for computing the confluent hypergeometric series is also presented     

Performance analysis of maximal ratio transmission with receiver antenna selection over correlated Nakagami-m fading channels

In this paper, we develop a framework to analyze the performance analysis of multi-antenna system that employ maximal-ratio transmission with receive antenna selection (MRT/RAS) over correlated Nakagami-m fading channels. We derive the probability density function (pdf) of the post processing signal-to-noise ratio at the output of the decoder, when spatial fading correlation is assumed. Utilizing the pdf, a closed-form analytical expression is derived in terms of channel capacity, outage probability and symbol error rate (SER) of M-ary modulation schemes. It can be observed that the performance loss in terms of capacity and SER is negligible when the separation between adjacent antennas is as large as 0.5 for exponential correlation model. Numerical outcomes considering the spatial correlation represent the performance characteristics and analyze their impacts on channel capacity, outage probability and SER of MRT/RAS system.

     

Moment Generating Function Based Performance Analysis of Maximal-Ratio Combining Diversity Receivers in the Generalized-K Fading Channels

In this paper, we have analyzed the performance of maximal ratio combing (MRC) diversity receiver of the wireless communication systems over the composite fading environment, which is modelled by using the generalized-K distribution. However, this distribution has been considered as a versatile distribution for the precise modelling of a great variety of the short-term fading in conjunction with the long-term fading (shadow fading) channel conditions. In this proposed analysis, we have derived the mathematical expression for the moment generating function (MGF) of the generalized-K fading channel model that is used to evaluate a novel closed-form expression of the average bit error rate for (BER) the binary phase-shift keying /binary frequency-shift keying and average symbol error rate (SER) for the rectangular quadrature amplitude modulation scheme. We have also derived the mathematical expressions for the outage probability as well as the channel capacity for the generalized-K fading channel model.     

Predetection Switched Combining in Correlated Rician Fading

The performance of dual-branch predetection switch-and-stay combining (SSC) in correlated Rician fading is considered in conjunction with several modulation formats. Analytical expressions are derived for the average symbol error rate (SER) of predetection SSC in correlated Rician fading. Switching thresholds that minimize the average SER are obtained. The impact of fading factor and the fading correlation on the performance of predetection SSC is studied. Analytical expressions for the output average signal-to-noise ratio (SNR) and the outage probability are derived. The validity of the analytical expressions are verified using Monte Carlo simulation.     

Unified asymptotic analysis of linearly modulated signals in fading, non-Gaussian noise, and interference

In this paper, we present a unified asymptotic symbol error rate (SER) analysis of linearly modulated signals impaired by fading and (possibly) non-Gaussian noise, which in our definition also includes interference. The derived asymptotic closed-form results are valid for a large class of fading and noise processes. Our analysis also encompasses diversity reception with equal gain and selection combining and is extended to binary orthogonal modulation. We show that for high signal-to-noise ratios (SNRs) the SER of linearly modulated signals depends on the Mellin transform of the probability density function (pdf) of the noise. Since the Mellin transform can be readily obtained for all commonly encountered noise pdfs, the provided SER expressions are easy and fast to evaluate. Furthermore, we show that the diversity gain only depends on the fading statistic and the number of diversity branches, whereas the combining gain depends on the modulation format, the type of fading, the number of diversity branches, and the type of noise. An exception are systems with a diversity gain of one, since their combining gain and asymptotic SER are independent of the type of noise. However, in general, in a log-log scale for high SNR the SER curves for different types of noise are parallel but not identical and their relative shift depends on the Mellin transforms of the noise pdfs.     

Average SER Performance of Distributed Antenna Systems Over Shadowed Generalized-Gamma Channels for Different Modulation Schemes

Recently, much attention has been drawn to distributed antenna systems (DAS), which are proposed to improve the performance of mobile communication systems. This paper focuses on the analysis of the average symbol error rate (SER) of DAS over a generic composite channel. Initially, a new composite channel model is considered for DAS, which is a mixture of path loss, lognormal shadowing and generalized-Gamma fast fading. This composite channel model is a generic model, which includes many well-known composite channel models as special cases. Based on the channel model, the cumulative distribution function of the output signal-to-noise ratio is obtained by employing selective transmission scheme. Moreover, by averaging the channel conditions and the positions of the MS in the cell, an approximate expression of the average SER is derived, which is a unified form of expression for many commonly used modulation schemes. Numerical results show that the derived expression of the average SER can provide sufficient precision for evaluating the SER performance of DAS under different modulation schemes.     

End-to-end SER of MRT/MRC and SC in multi-hop wireless sensor networks

The purpose of this study is to express analytically the end-to-end (e2e) symbol error rate (SER) in multi-hop decode-and-forward relaying in wireless sensor networks. These may occur in independently distributed cascaded Nakagami-m fading channels that may or may not be identical. In this study, all sensor terminals show mobility and this study is possibly the first one that undertakes performance analysis of maximal ratio transmission/maximum ratio combining and selection combining diversity that enables a better system performance in a multi-hop wireless sensor transmission system. In this paper, the first step undertaken was to generate a closed-form expression of the probability distribution function (PDF), the cumulative distribution function, and the moment-generating function for the system being examined. This discovery helped in the evaluation of the eventual performance of the system as far as e2e SER is concerned. It also helped in determining the upper limits of SER expressions for high signal-to-noise ratios. In the next phase, the intended system was utilized in an accurate approximation of the PDF of the cascaded Rayleigh fading channels to compare the findings acquired thus with those derived by its use in the actual PDF of the cascaded Rayleigh fading channels. These analytical findings were then validated with the help of Monte-Carlo simulations.

     

Performance Analysis of Alamouti Space-Time Block Code Over Time-Selective Fading Channels

Alamouti orthogonal space-time block code (Alamouti in IEEE J Sel Areas Commun 16(8):1451–1458, 1998) has been applied widely in wireless communication, e.g., IEEE 802.16e-2005 standard. In this paper, theoretical analysis of symbol error rate performance for Alamouti orthogonal space-time block code (AOSTBC) over time-selective fading channels with a zero-forcing linear receiver is derived. Firstly, a closed-form expression (i.e., not in integral form) is derived for the average symbol pair-wise error probability (SPEP) in time-selective frequency-nonselective independent identically distributed Rayleigh fading channels. Then, the SPEP is used to derive a tight upper bound (UB) for the symbol-error rate (SER) of AOSTBC via establishing algorithmic Bonferroni-type upper bound. Extensive simulation results show that the curves for the UB coincide with the simulated SER curves for various antenna configurations even at very low signal-to-noise ratio regimes. The UB thus can be used to accurately predict the performance of AOSTBC code over time-selective fading channels when a zero-forcing receiver is used.     

Nakagami-m衰落信道下空时分组码的性能估计

基于等效单输入单输出SISO (Single-input Single-output) 模型,利用矩量母函数 (MGF) 分析法,空时分组码STBC (Space-Time Block Coding) 的误符号率是可以得到其准确闭式表达式的.对于独立同分布Nakagami-m衰落信道下的空时分组码的性能进行了研究,给出了采用M-PSK 和M-QAM调制方案的不同空时分组编码矩阵误符号率的闭式解以及基于闭式解的解析性能结果,通过蒙特卡洛仿真验证了闭式解的准确性.还从调制方案的角度对于几种新的空时分组码的性能进行了一些新的讨论.     

选择性放大传送协同通信在Nakagami信道中的性能分析

该文根据两个统计独立非负随机变量的调和平均值的概率密度函数在零点的变化特性,分析了选择性放大传送协同协议在Nakagami衰落信道中的性能,得出了高信噪比时系统误符号率的闭合表达式。理论分析和数值仿真结果表明,在Nakagami信道中选择性放大传送协同协议可获得和传统放大传送协同协议一样的分集阶数,并且具有更优的误符号率性能。     

考虑混合SC/MRC分集的层叠分布式天线系统SER性能分析

针对Nakagami/lognormal复合衰落信道,研究了层叠分布式天线系统(Cascade Distributed Antenna System-CDAS)在CDMA网络中的平均误符号率性能.推导出了采用混合SC/MRC分集接收机的层叠分布式天线系统平均误符号率性能公式.利用推导出的平均误符号率表达式,分析了多径密度函数(Multipath Intensity Profile-MIP)衰减因子、空时分集维数、活动用户数以及阴影衰落因子对平均误符号率性能的影响.仿真表明层叠分布式天线系统可以有效对抗衰落,提高系统容量以及削弱对数正态阴影衰落的影响.     

相位调制的多用户OFDM-FH通信系统性能分析

 本文研究一种高效的通信方式,即相位调制的OFDM-FH通信系统。为了提高衰落信道下系统误码率性能,接收端采用最大比合并的分集接收技术。利用特征函数方法,推导该系统在加性高斯白噪声信道和瑞利衰落信道时系统误码率性能。给出误比特率与跳频频点数 ,OFDM子载波数N和用户数 等参数之间的关系。理论分析和仿真实验结果表明,在相同参数条件下,基于相位键控调制的OFDM-FH多址接入系统与其它OFDM-FH通信系统比较,具有系统频带宽度占用少、误比特率低等优势。