Mehmet BİLİM

Makale/Derleme | 2019 | Elsevier

In this study, average symbol error rate (ASER) expressions for rectangular quadrature amplitude modulation (RQAM) and cross quadrature amplitude modulation (XQAM) over κ−μ shadowed fading are proposed by considering two different system models. In the first system model, a single-input– single-output (SISO) scheme is considered while a multiple-input–multiple-output (MIMO) with single transmit antenna selection and maximal ratio combining (TAS/MRC) is investigated as a second system model. First, the exact, approximate and asymptotic ASER expressions of RQAM and XQAM for a SISO system model are proposed based on probability density . . . function (PDF) of instantaneous signal- to-noise ratio (SNR). Second, ASER expressions of RQAM and XQAM schemes for a MIMO system with TAS/MRC are obtained by using the PDF of instantaneous SNR at the receiver side. Then, ASER performances of RQAM and XQAM for the considered two system models are compared in the presence of different fading configurations. Finally, our numerical results illustrate that the analytical ASER expressions proposed in this study are well agreement with their simulations Daha fazlası Daha az

Mehmet BİLİM

Makale/Derleme | 2019 | IET

This Letter presents capacity analysis of Fisher–SnedecorFfadingchannels under different transmission strategies. To this end, novelanalytical expressions are proposed for optimal rate adaptation withconstant transmit power, channel inversion with afixed rate and trun-cated channel inversion withfixed rate schemes in this Letter. Then,analytical results are illustrated for different fading and shadowingparameter values.

Mehmet BİLİM

Makale/Derleme | 2018 | Wiley

This paper analyzes the performance of cooperative decode‐and‐forward (DF)interleave‐division multiple‐access (IDMA) networks with best relay selectionover Rayleigh/Weibull fading environments. In the analysis, approximate out-age probability (OP) and bit error probability (BEP) expressions are derivedfor the considered system. Further, a 2‐hop DF IDMA system is also designedto compare with cooperative one. We propose OP and BEP expression for 2‐hop DF IDMA systems. Numerical results are obtained by changing the num-ber of relays and the value of fading parameter in the proposed expressions.Also, simulations are provided to corrobor . . .ate the exactness of the derivedapproximate OP and BEP expressions Daha fazlası Daha az

Mehmet BİLİM

Makale/Derleme | 2018 | Elsevier

In this paper, bit error probability (BEP), outage probability (OP) and channel capacity (CC) of direct-sequence code-division multiple access systems with amplify-and-forward relaying are presented for different fading scenarios. In the first scenario, the source-destination link is assumed to experience Rayleigh fading while it is subject to Nakagami-m fading in the second scenario. The source-relay and relay-destination channels are considered to have Nakagami-m fading conditions in two scenarios. First, analytical expressions for the end-to- end probability density function (PDF) are derived by using the convolution integral. Th . . .en, BEP, OP and CC are obtained based on these PDFs in terms of infinite series. Truncation error analyses are presented for different parameter values in order to show that truncation error arising from the infinite series is negligible. Simple and easy-to-compute asymptotic expressions are also introduced for BEP and OP in order to simplify the performance analysis in high signal-to-noise ratio region. Simulation results are provided to show the accuracy of the pro- posed approximate and asymptotic expressions Daha fazlası Daha az

Mehmet BİLİM

Makale/Derleme | 2020 | IEEJ Transactions on Electrical and Electronic Engineering

The performance of effective throughput (ET) over alternate Rician-shadowed fading channels is analyzed. A novel expressionfor the exact ET is obtained in terms of the Meijer’sGfunction. Moreover, an asymptotic ET expression at the high signal-to-noise ratio regime is also derived to gain more insight. In order to prove the correctness of our analytical derivations, somecomparisons between the exact simulations and numerical results are presented. The results demonstrate that increasing the valueofmshadowing fading is more dominant than the value ofKi(i∈{1, 2}) Rician parameters since this means a weak shadowingcondition.©2020 Insti . . .tute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc Daha fazlası Daha az

Mehmet Bilim

Makale/Derleme | 2020 | Physical Communication

In this paper, the performance of single-input-multiple-output (SIMO) networks which represented an uplink communication with additive generalized Gaussian noise (AWGGN) over non-homogeneous fading conditions such as – , – , and – are analyzed. First, approximate error probability ( ) expressions are presented for SIMO operating in – , – , and – fading channels by using the probability density functions (PDF) of the instantaneous signal-to-noise ratio at the receiver side. Then, the asymptotic expressions based on these PDF expressions are also derived. To these end, we show the performances for different configurations of fading pa . . .rameters, the number of receiver antennas, modulation schemes, and noise types. Finally, the exact simulations are provided to evaluate the accuracy of the proposed analytical frameworks for the considered system models Daha fazlası Daha az

Mehmet BİLİM

Makale/Derleme | 2020 | Pamukkale Üniversitesi Mühendislik Bilimleri Dergisi

Bu çalışmada, evre uyumlu olmayan frekans kaydırmalı anahtarlama ve farksal faz kaydırmalı anahtarlama sayısal modülasyon türlerini kullanan haberleşme sistemlerinin η-µ/Gamma karma sönümlenmeli kanallardaki başarım analizi verilmiştir. Yapılan analiz olasılık yoğunluk fonksiyonu tabanlı olup, matematiksel olarak temel fonksiyonlar içermektedir. Bu sebeple, sunulan analiz matematiksel açıdan oldukça kolay ve anlaşılabilirdir. Yapılan analizler sonucunda kapalı formda ortalama hata ifadesi türetilmiştir. Türetilen hata ifadesi kullanılarak elde edilen nümerik sonuçlar ile simülasyon sonuçları kıyaslamalı olarak verilerek türetilen if . . .adenin doğruluğu gösterilmiştir. In this study, performance analysis of η-μ/Gamma mixed fading channels of communication systems using noncoherent frequency shift keying and differential phase shift keying digital modulation types is presented. The analysis is based on probability density function and contains mathematically basic functions. For this reason, the proposed analysis is quite simple and understandable from a mathematical point of view. As a result of the analyzes, the closed form average error probability expression is derived. The numerical results obtained by using the derived error expression are compared with the simulation results and the accuracy of the derived expression is shown Daha fazlası Daha az

Mehmet BİLİM

Bildiri | 2020 | 28 İşaret İşleme ve İletişim Sempozyumu , pp.1 - 4

Bu çalışmada, iki kollu tek girişli çok çıkışlı (singleinput multiple-output, SIMO) sistemlerin λ-μ sönümlü kanallardaki hata başarımı analiz edilmiştir. Ele alınan sistemin hata olasılığı için Chernoff yaklaşıklığı kullanılarak analitik bir ifade türetilmiştir. Daha sonra, ele alınan sistem için bir asimptotik hata ifadesi de önerilmiştir. Türetilen yaklaşık ifadeden elde edilen yaklaşık sonuçlar ile tam sonuçlar kıyaslamalı olarak sunulmuştur. Nümerik sonuçlar, sönümlenme parametresi ile anten sayısının farklı değerlerinin ve modülasyon türünün etkisini analiz etmek üzere farklı konfigürasyonlar için verilmiştir. Sonuçta, önerilen . . . ifadeden elde edilen yaklaşık sonuçların tam sonuçlara oldukça yakın olduğu gözlenmiştir. In this work, error performance of dual-branch single-input multiple-output (SIMO) systems is analyzed over λ-μ fading channels. An analytical expression is derived by using Chernoff approximation for the error probability of the considered system. Then, an asymptotic error expression is also proposed for the considered system. The results obtained from the derived expression are presented in comparison with exact results. Numerical results are shown for different configurations in order to analyze the effects of different values of fading parameter, antenna number and modulation type. In conclusion, it is observed that the approximate results are close to the exact results. Daha fazlası Daha az

Mehmet BİLİM

Makale/Derleme | 2019 | Wireless Personal Communications

This paper presents new analytical solutions for integrals that involve exponential functions, Gaussian Q- function and arbitrary powers. The ofered expressions are both simple and convenient which are useful in applications for the derivation of the average error probability in diferent wireless communication environments such as α–µ and η–µ fading channels. To this end, the derived closed-form solutions are validated by computer simulations.

Mehmet BİLİM

Makale/Derleme | 2019 | Accepted 29 September 2019 Keywords: Generalized j-l shadowed fading Selection combining and maximal ratio combining receivers Average bit error probability Outage performance Channel capacity a b s t r a c t In this study, N-branch selection combining (SC), dual-branch SC and dual-branch maximal ratio combin- ing (MRC) receivers over j-l shadowed fading channels are investigated in terms of average bit error probability (BEP), outage probability (OP) and channel capacity (CC). Firstly, a cumulative distribution function (CDF) expression for instantaneous signal-to-noise ratio (SNR) at the output of the N-branch SC system over a j-l shadowed fading channel is derived. Based on the proposed CDF expression of out- put SNR for N-branch SC receiver, OP and approximate average BEP expressions are obtained. Secondly, the probability density function (PDF) expression for a dual-branch SC system over j-l shadowed chan- nels is derived. Then, two different CC expressions of a dual-branch SC receiver are obtained by using the proposed PDF expression. Thirdly, a PDF expression for a dual-branch MRC system under j-l shadowed conditions is proposed and its CC expression with channel inversion with fixed rate for is derived. Effects of the fading parameters and the total number of branches on the system performance are examined with different scenarios. Finally, the obtained results from OP, average BEP and CC expressions are verified with numerical simulations. Ó 2019 Elsevier GmbH. All rights reserved. 1. Introduction Diversity combining methods are mostly employed in advanced wireless consumer instruments such as smartphones, WiFi routers and, laptops, to develop connection reliability and power effi- ciency. Selection combining (SC) is still one of the popular diversity techniques to combat the effects of fading in wireless environ- ments. From the implementation point of view, SC is beneficial to quantify the tradeoff between reduction in complexity and decrement in system performance. In this context, several works have studied the performance of communication systems with an SC receiver using the different fading channels in the last few years [1–11]. In [1], some analytical results for SC diversity over Weibull and Nakagami-m fading models were proposed by using the prob- ability density function (PDF) of these channel distributions. In [2], novel and exact expressions were presented for the outage proba- bility (OP) of N-branch receiver diversity which includes SC under correlated log-normal links. Subsequently, the authors in [3] pro- vided asymptotic and closed-form upper bound expressions for the error rate and the OP performance of an SC model over Nakagami-m fading conditions. Most of the latest works have considered different system model with SC over Nakagami-m fading links [4–10]. While a closed-form expression for average symbol error rate (SER) was proposed for general order rectangular quadrature amplitude mod- ulation in [4], the study in [5] analyzed SC dual-hop dual-branch amplify-and-forward relaying in the presence of Nakagami-m fad- ing. As different system models, Deng et al. and Lei et al. consid- ered transmit antenna selection with SC receiver for cognitive decode-and-forward relaying and single-input multiple-output underlay cognitive radio systems with SC in Nakagami-m faded, respectively in [6,7]. In another work in [8], the analytical deriva- tions for the outage and SER performance were obtained for unequal power dual-branch Nakagami-0.5 linear diversity combin- ing techniques with SC diversity. The authors in [9] presented the performance analysis of two-way full duplex relay with antenna selection over Nakagami channels. Similar to [9], in [10], the per- formance of multi-hop relaying caching for Nakagami conditions is analyzed. Obviously, all the channels for the studies in [1–10] were assumed to experience Nakagami-m or Weibull fading. How- ever, these channel models can be inadequate for representing the real channel environments. By considering a different fading model, a new average symbol error probability of an SC receiver over Gamma fading is presented by using PDF expression [11]. https://doi.org/10.1016/j.aeue.2019.152934 1434-8411/Ó 2019 Elsevier GmbH. All rights reserved. E-mail address: mbilim@nny.edu.tr Int. J. Electron. Commun. (AEÜ) 112 (2019) 152934 Contents lists available at ScienceDirect International Journal of Electronics and Communications (AEÜ)

In this study, N-branch selection combining (SC), dual-branch SC and dual-branch maximal ratio combining (MRC) receivers over κ-μ shadowed fading channels are investigated in terms of average bit error probability (BEP), outage probability (OP) and channel capacity (CC). Firstly, a cumulative distribution function (CDF) expression for instantaneous signal-to-noise ratio (SNR) at the output of the N-branch SC system over a κ-μ shadowed fading channel is derived. Based on the proposed CDF expression of output SNR for N-branch SC receiver, OP and approximate average BEP expressions are obtained. Secondly, the probability density functi . . .on (PDF) expression for a dual-branch SC system over κ-μ shadowed channels is derived. Then, two different CC expressions of a dual-branch SC receiver are obtained by using the proposed PDF expression. Thirdly, a PDF expression for a dual-branch MRC system under κ-μ shadowed conditions is proposed and its CC expression with channel inversion with fixed rate for is derived. Effects of the fading parameters and the total number of branches on the system performance are examined with different scenarios. Finally, the obtained results from OP, average BEP and CC expressions are verified with numerical simulations Daha fazlası Daha az

Mehmet BİLİM

Makale/Derleme | 2019 | International Journal Of Communication Systems

Cooperative nonorthogonal multiple access (NOMA) system is an effective solution for the fifth generation (5G) wireless mobile communications systems. In this work, the achievable rate analysis of a NOMA communication network with decode‐and‐forward (DF) relaying under κ‐μ shadowed fading conditions is investigated. First, we develop an analytical framework for cumulative distribution function (CDF) of the considered system model. Then, the average achievable rate expressions for two different information bits namely s1 and s2 are derived based on the derived CDF for NOMA with DF relaying over κ‐μ shadowed fading channels. Furthermo . . .re, we also propose simplified average achievable rate expressions for the special cases of κ‐μ shadowed fading channels in order to facilitate the evaluation of the derived expressions. Some numerical examples on the achievable rate of the considered system are shown for different scenarios. Moreover, our derived analytical average achievable rate expressions are confirmed by the simulations results Daha fazlası Daha az

Mehmet BİLİM

Makale/Derleme | 2019 | IEEE Access

In this study, analytical expressions are derived by using probability density function approach over millimeter wave fluctuating two-ray (FTR) fading channels for average symbol error rate (ASER) of rectangular quadrature amplitude modulation (RQAM) and cross quadrature amplitude modulation (XQAM) schemes. First, an exact ASER expression for RQAM over millimeter wave FTR fading channels is derived. Second, two different upper bound ASER expressions of RQAM scheme under millimeter wave FTR fading conditions are obtained by using Chernoff and Chiani approximations of Gaussian Q-function. In addition to this, an asymptotic ASER expres . . .sion for RQAM is also proposed. Then, an analytical formulation is presented for XQAM signaling over millimeter wave FTR fading channels in terms of infinite series representations which rapidly converge. Finally, the numerical results of the proposed analytical expressions are compared with the simulation results in order to validate the analytical findings in this work Daha fazlası Daha az