9 research outputs found

    Statističke karakteristike prvog i drugog reda signala u bežičnom telekomunikacionom sistemu sa selekcionim kombinovanjem

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    In doctoral dissertation, first and second order system performances of wireless communication system in the presence of fading and interference are considered. Theoretically, four cases are taken into consideration, and obtained numerical results are graphically presented and analyzed. Firstly, wireless mobile communication system with the receiver that contains automatic frequency control (AFC) loop operating over fading channel in the presence of single interference is considered. Performance measures, such as average switching rate (ASR) and mean time lose of lock (MTTL), are defined. In this doctoral dissertation, ASR and MTTL, for three different fading channels: Kg, α-μ and k-μ are obtained. In the next chapter, wireless relay communication system with two sections in the presence of multipath fading is considered. Signal envelope at the input of the receiver can be expressed as product of the first section signal envelope and the second section signal envelope. For such system model, average level crossing rate (LCR) for the case when radio relay system of the first section operates over Nakagami-m fading environment and second section operates over k-μ fading environment is obtained. Wireless relay system with two sections in the presence of non-linear α-μ fading channel is than taken into consideration. Moreover, radio relay system with two sections in the presence of multipath fading and interference is also considered. LCR of the ratio of the product of two k-μ random processes and k-μ random process is calculated. Finally, LCR of the ratio of Rician random process and product of two Rician random processes is obtained. Wireless communication system with two inputs SSC diversity receiver operating over correlated multipath η-μ fading in the presence of interference is than considered. Joint probability density function and joint distribution cumulative function of the ratios of signal to interference at inputs of SSC receivers are calculated. By using obtained expressions for probability density function (PDF), average bit error probability (ABER) for different coherent and non-coherent modulation schemes is obtained while by using derived cumulative distribution function (CDF), outage probability (OP) is obtained. At the end of doctoral dissertation, macrodiversity system with macrodiversity SSC receiver and two microdiversity SC receivers operating over Gamma shadowed multipath fading channel is proposed. In one case Nakagami-m multipath fading channel is considered while in the second case k-μ multipath fading is considered. System performances of the proposed system are derived and numerical results are graphically presented and discusse

    On the macrodiversity reception in the correlated Gamma shadowed Nakagami-m fading

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    U ovom radu je izložena analiza makrovišestrukog prijama za slučaj uporabe tehnike prostornog raščlanjenja sa selektivnim kombiniranjem (SC – selection combining) u prisustvu korelacijske Gamma sjene. Na mikrorazinama razmatrane su tehnike prostornog raščlanjenja kombiniranja s maksimalnim odnosom (MRC – maximal ratio combining) za ulazne korelirane grane, kako bi se sprječio utjecaj brzog Nakagami-m fedinga. Prvo su izvedeni izrazi u zatvorenom obliku za statističke karakteristike sustava drugog reda: srednji broj osnih presjeka (LCR – level crossing rate) i srednje vrijeme trajanja slabljenja (AFD – average fade duration). Na osnovu ovih izraza, kroz njihove priraštaje analiziran je utjecaj korelacije na makrorazini (korelacije zasjenjenja) na karakteristike sustava. Analiza prezentirana u ovom radu, može biti od značaja u procesu projektiranja makroraščlanjenih sustava.In this paper an analysis of selection combining (SC) macrodiversity reception performed in correlated Gamma shadowing environment will be presented. At each microlevel maximal ratio combining (MRC) with correlated branches is observed, for mitigating effects of Nakagami-m short-time fading. First, novel closed form expressions are derived for second order statistical measures, level crossing rate (LCR) and average fade duration (AFD). Capitalizing on these expressions, the influence of correlation at macrolevel (shadowing correlation) will be analysed through their derivatives. Provided analysis could find application in current macrodiversity system design

    The LCR of wireless macrodiversity SSC receiver in the presence of gamma shadowed Kappa-Mu fading

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    Wireless mobile macrodiversity (MaD) radio system with switch and stay (SSC) receiver and two microdiversity (MiD) selection combining (SC) branches operating over Gamma shadowed Kappa-Mu (k-μ) multipath fading environment is considered. Novel, one-folded integral expression for average level crossing rate (LCR) of MaD SSC receiver output signal envelope is obtained. Numerical results of the proposed model are presented and discussed in relation to the system model parameters

    ANALYTICAL APPROACH IN ESTIMATING ERROR PERFORMANCE OF PARTIALLY COHERENT PSK RECEIVER OVER KAPPA-MU FADING

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    In this paper, a novel analytical expression for the symbol error probability (SEP) of M-ary Phase-Shift Keying (MPSK) signal transmission is derived, by using the Fourier series method (FSM). The signal is transmitted over k-m fading channel. The hardware imperfections in PSK demodulator are taken into consideration, and  are presented through the phase noise described by Tikhonov distribution. Based on the derived SEP expression, numerical results are presented and discussed. It is illustrated that the existence of phase noise leads to the irreducible SEP floor which degrades  the system performance to a large extent

    OUTAGE PERFORMANCE OF MULTI-BRANCH SC RECEIVER OVER CORRELATED WEIBULL CHANNEL IN THE PRESENCE OF CORRELATED RAYLEIGH CO-CHANNEL INTERFERENCE

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    The aim of this paper is to consider the performance of wireless communication system with signal-to interference ratio (SIR) based multiple-branches selection combining (SC) receiver. The proposed system operates over correlated Weibull multipath environment, in the presence of co-channel interference (CCI) subjected to correlated Rayleigh multipath fading. SC diversity technique is used to reduce the effects of multipath fading and CCI on the system performance. Infinite-series expression for outage probability (OP) in terms of Meijer G functions is derived. Further, numerical results are graphically presented and discussed to show the influence of fading parameters on outage probability

    Statističke karakteristike prvog i drugog reda signala u bežičnom telekomunikacionom sistemu sa selekcionim kombinovanjem

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    In doctoral dissertation, first and second order system performances of wireless communication system in the presence of fading and interference are considered. Theoretically, four cases are taken into consideration, and obtained numerical results are graphically presented and analyzed. Firstly, wireless mobile communication system with the receiver that contains automatic frequency control (AFC) loop operating over fading channel in the presence of single interference is considered. Performance measures, such as average switching rate (ASR) and mean time lose of lock (MTTL), are defined. In this doctoral dissertation, ASR and MTTL, for three different fading channels: Kg, α-μ and k-μ are obtained. In the next chapter, wireless relay communication system with two sections in the presence of multipath fading is considered. Signal envelope at the input of the receiver can be expressed as product of the first section signal envelope and the second section signal envelope. For such system model, average level crossing rate (LCR) for the case when radio relay system of the first section operates over Nakagami-m fading environment and second section operates over k-μ fading environment is obtained. Wireless relay system with two sections in the presence of non-linear α-μ fading channel is than taken into consideration. Moreover, radio relay system with two sections in the presence of multipath fading and interference is also considered. LCR of the ratio of the product of two k-μ random processes and k-μ random process is calculated. Finally, LCR of the ratio of Rician random process and product of two Rician random processes is obtained. Wireless communication system with two inputs SSC diversity receiver operating over correlated multipath η-μ fading in the presence of interference is than considered. Joint probability density function and joint distribution cumulative function of the ratios of signal to interference at inputs of SSC receivers are calculated. By using obtained expressions for probability density function (PDF), average bit error probability (ABER) for different coherent and non-coherent modulation schemes is obtained while by using derived cumulative distribution function (CDF), outage probability (OP) is obtained. At the end of doctoral dissertation, macrodiversity system with macrodiversity SSC receiver and two microdiversity SC receivers operating over Gamma shadowed multipath fading channel is proposed. In one case Nakagami-m multipath fading channel is considered while in the second case k-μ multipath fading is considered. System performances of the proposed system are derived and numerical results are graphically presented and discusse

    The Distribution of the Ratio of the Products of Two Independent α-μ Variates and Its Application in the Performance Analysis of Relaying Communication Systems

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    We present novel general, simple, exact, and closed-form expressions for the probability density function (PDF) and cumulative distribution function (CDF) of the ratio of the products of two independent α-μ variates, where all variates have identical values of alpha parameter. Obtained results are applied in analysis of multihop wireless communication systems in different fading transmission environments. The proposed theoretical analysis is also complemented by various graphically presented numerical results

    Analytical performance analysis of the M2M wireless link with an antenna selection system over interference limited dissimilar composite fading environments

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    This paper considers direct mobile-to-mobile (M2M) communications with a dual antenna selection (AS) system at a destination mobile node (DMN) in interference limited, dissimilar composite fading environments. In particular, we model dissimilar interference limited signals at the inputs of the dual branch AS system as (i) the ratio of two Nakagami-m (N) random variables (RVs) at the first branch and (ii) the ratio of two Rice RVs at the second branch, in order to account for non line-of-sight (NLOS) and line-of-sight (LOS) communications, respectively. Moreover, we assume variable powers of the desired as well as interference signals at the output of the DMN in order to account for the impact of shadowing. For the proposed model, we derive probability density functions, cumulative distribution functions, outage probabilities and average level crossing rates. The derived statistical results are evaluated for all the statistical measures considered and are graphically presented in order to provide insight into the impact of composite fading severities and LOS factors for the desired signal, as well as for the interference, on the system performances
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