24 research outputs found
On the Performance Analysis of Wireless Receiver in Cascaded Fading Channel
In this paper, we provide a unified analysis for wireless system over cascaded fading channels modeled either by cascaded Nakagami-m or Weibull fading models. These cascade fading models are developed by the product of independent Nakagami-m or Weibull random variables, which are not necessary identically distributed. The performance measures such as amount of fading, average bit error rate, and signal outage are computed in this analysis. We first use the Padé approximation (PA) technique to find simple to evaluate rational expressions for the moment generating function (MGF) of output signal-to-noise ratio (SNR), unlike previously derived intricate expressions in terms of MeijerG function for cascaded Nakagami-m fading channel. Rational expressions for the MGF of the cascaded Weibull random variable are also computed to provide new set of performance results. Using these rational expressions, we analyze the performance of wireless receivers under a range of representative channel fading conditions using
both cascaded fading models. To verify the correctness of the proposed rational expression formulation numerical and computer simulations has been done, which shows perfect match
A Formulation of the Log-Logistic Distribution for Fading Channel Modeling
In some scenarios, the log-logistic (LL) distribution is shown to provide the best fit to field
measurements in the context of wireless channel modeling. However, a fading channel model based
on the LL distribution has not been formulated yet. In this work, we introduce the L-distribution
as a reformulation of the LL distribution for channel modeling purposes. We provide closed-form
expressions for its PDF, CDF, and moments. Performance analysis of wireless communication systems
operating under L-fading channels is exemplified, providing exact and asymptotic expressions for
relevant metrics such as the outage probability and the average capacity. Finally, important practical
aspects related to the use of the L-distribution for channel fitting purposes are discussed in two
contexts: (i) millimeter-wave links with misaligned gain, and (ii) air–ground channels in unmanned
aerial vehicle communications.European Social and Regional FundsJunta de Andalucia P18-RT-3175
UMA20-FEDERJA-002Universidad de MalagaUniversidad de Granad
MIMO Sistemlerde Alamouti Uzay Zaman Blok Kodlamanın Weibull Sönümleme Kanalı Üzerindeki Performans Analizi
Kablosuz haberleşme sistemlerinin
performansı kanal sönümlemelerinden etkilenmektedir. Yeni nesil kablosuz sistemlerin
gelişimiyle beraber güvenilir bağlantı ihtiyaçları da artmaktadır. Kablosuz
iletişimdeki en büyük zorluk, sönümlemelerden en az etkilenen kesintisiz
iletişimin gerçekleştirilmesidir. Çeşitleme teknikleri ile çoklu anten
teknolojileri bu noktada yardımcı olmaktadır. Bu çalışmada, alıcı ve vericide
kullanılan Çoklu Giriş Çoklu Çıkış (MIMO) anten yapısı, hem iç hem de dış
ortamdaki radyo yayılım ortamını modelleyen Weibull sönümleme kanalı ve İkili
Faz Kaydırmalı Anahtarlama (BPSK) modülasyonu altında vericide çeşitleme
tekniklerinden olan Alamouti Uzay Zaman Blok Kodlamanın (STBC) performansı
analiz edilmiştir. Weibull sönümleme kanalında çoklu anten ve STBC
kullanılmasının, Bit Hata Oranını (BER) azalttığı ve sistem performansını arttırdığı
gözlemlenmiştir
Performance analysis of dual-branch selection diversity receiver that uses desired signal algorithm in correlated Weibull fading environment
Rad je usmjeren na analizu karakteristika višestrukog sustava selektivnog kombiniranja (SC) s dvije grane gdje su i interferencija željenog signala i ko-kanalna interferencija (CCI) izložene Weibull fedingu. Za slučaj kada se algoritam željenog signala rabi kao kriterij za donošenje odluke izvedeni su izrazi zatvorenog oblika za zajedničku funkciju raspodjele vjerojatnosti (PDF) željenog signala i interferencije kao i PDF za trenutačni odnos signal-interferencija (SIR) na izlazu sustava. Ovi se izrazi rabe za analizu karakteristika cijeloga sustava rabeći vjerojatnost otkaza sustava, prosječnu vjerojatnost greške bita (ABEP) i prosječni izlaz SIR kao mjere za karakteristike sustava. Konačno, rezultati dobiveni u ovom radu uspoređeni su s ranije objavljenim rezultatima za isti sustav koji rabi algoritam na bazi SIR-a.This paper focuses on performance analysis of dual-branch selection combining (SC) diversity system where both, desired signal as well as co-channel interference (CCI), are subjected to Weibull fading. For the case when desired signal algorithm is used as decision criterion, closed form expressions for joint probability density function (PDF) of desired signal and interference as well as PDF for instantaneous signal-to-interference ratio (SIR) at the system output are derived. These expressions are used for overall system performance analysis using outage probability, average bit error probability (ABEP) and average output SIR as system performance measures. Finally, the results obtained in this paper are compared to the previously published results for the same system that uses SIR based algorithm
PERFORMANCE COMPARISON OF DUAL-BRANCH AND TRIPLE-BRANCH SELECTION DIVERSITY RECEIVER BASED ON DESIRED SIGNAL ALGORITHM OVER CORRELATED WEIBULL FADING CHANNELS
As an important performance measure, in this paper the outage probability of dual- and triple-branch selection combining (SC) diversity system is compared. The analyzed system works over correlated Weibull fading channels in the presence of cochannel interference (CCI) where the output signal choice is done using desired signal algorithm. Results are graphically presented showing the influence of number of diversity branches, correlation coefficient and ratio of average powers of desired and interference signal
SECOND ORDER STATISTICS OF DUAL SELECTION DIVERSITY OVER CORRELATED WEIBULL FADING CHANNELS IN THE PRESENCE OF INTERFERENCE
In this paper, second order statistics of dual selection combining (SC) system applying desired signal decision algorithm are obtained for the case when that diversity system operates in Weibull interference-limited environment. Namely, a novel closed-form expression for outage probability (OP), necessary for an analysis of average fade duration (AFD), in the term of Meijer’s G-function is derived for general case in which desired signal and cochannel interference (CCI) are exposed to fading with different severities. Depending on fading environment, semi-analytical and analytical expressions for average lever crossing rate (LCR) are obtained, too. Numerical results are presented to accomplish proposed mathematical analysis and to examine the effects of system and channel parameters on concerned quantities
PERFORMANCE ANALYSIS OF DUAL-BRANCH SELECTION DIVERSITY SYSTEM USING NOVEL MATHEMATICAL APPROACH
In this paper, novel mathematical approach for evaluation of probability density function (PDF) of instantaneous signal-to-interference ratio (SIR) at the receiver output in interference-limited environment is proposed. Dual-branch selection combining (SC) receiver operating over correlated Weibull fading channels applying SIR algorithm is considered. Analytical expression for joint PDF of desired signal and interference at the receiver output is derived and used for evaluation of PDF of instantaneous SIR. The expression for PDF of SIR is used for system performance analysis via outage probability, average bit error probability (ABEP) and average output SIR as system performance measures. Numerical results are graphically presented showing the effects of fading severity, average SIR at the input and level of correlation on the diversity receiver performance. In addition, results obtained for the PDF of instantaneous SIR in this paper, are compared to the results when the PDF of instantaneous SIR is directly calculated