692 research outputs found
Dual-Branch MRC Receivers under Spatial Interference Correlation and Nakagami Fading
Despite being ubiquitous in practice, the performance of maximal-ratio
combining (MRC) in the presence of interference is not well understood. Because
the interference received at each antenna originates from the same set of
interferers, but partially de-correlates over the fading channel, it possesses
a complex correlation structure. This work develops a realistic analytic model
that accurately accounts for the interference correlation using stochastic
geometry. Modeling interference by a Poisson shot noise process with
independent Nakagami fading, we derive the link success probability for
dual-branch interference-aware MRC. Using this result, we show that the common
assumption that all receive antennas experience equal interference power
underestimates the true performance, although this gap rapidly decays with
increasing the Nakagami parameter of the interfering links. In
contrast, ignoring interference correlation leads to a highly optimistic
performance estimate for MRC, especially for large . In the low
outage probability regime, our success probability expression can be
considerably simplified. Observations following from the analysis include: (i)
for small path loss exponents, MRC and minimum mean square error combining
exhibit similar performance, and (ii) the gains of MRC over selection combining
are smaller in the interference-limited case than in the well-studied
noise-limited case.Comment: to appear in IEEE Transactions on Communication
MGF Approach to the Analysis of Generalized Two-Ray Fading Models
We analyze a class of Generalized Two-Ray (GTR) fading channels that consist
of two line of sight (LOS) components with random phase plus a diffuse
component. We derive a closed form expression for the moment generating
function (MGF) of the signal-to-noise ratio (SNR) for this model, which greatly
simplifies its analysis. This expression arises from the observation that the
GTR fading model can be expressed in terms of a conditional underlying Rician
distribution. We illustrate the approach to derive simple expressions for
statistics and performance metrics of interest such as the amount of fading,
the level crossing rate, the symbol error rate, and the ergodic capacity in GTR
fading channels. We also show that the effect of considering a more general
distribution for the phase difference between the LOS components has an impact
on the average SNR.Comment: 14 pages, 8 Figures and 2 Tables. This work has been accepted for
publication at IEEE Transactions on Wireless Communications. Copyright (c)
2014 IEEE. Personal use of this material is permitted. However, permission to
use this material for any other purposes must be obtained from the IEEE by
sending a request to [email protected]
Second Order Statistics of -Fisher-Snedecor Distribution and Their Application to Burst Error Rate Analysis of Multi-Hop Communications
An advantage of using the composite fading models (CFMs) is their ability to concurrently address the impact of multi-path and shadowing phenomena on the system performance in wireless communications. A Fisher-Snedecor (FS) F CFM has been recently proposed as an experimentally verified and tractable fading model that can be efficiently applied for 5G and beyond 5G wireless communication systems. This paper provides second-order (s-order) performance analysis of the product of N independent but not identically distributed (i.n.i.d) FS F random variables (RVs). In particular, accurate and closedform approximations for level crossing rate (LCR) and average fade duration (AFD) of the product of N i.n.i.d FS F(N-FS F) RVs are successfully derived by exploiting a general property of a Laplace approximation method for evaluation of the N -folded integral-form LCR expression. Based on the obtained s-order statistical results, the burst error rate and maximum symbol rate of the N -FS F distribution are addressed and thoroughly examined. The numerical results of the considered performance measures are discussed in relation to the N-FS F multi-path and shadowing severity parameters. Moreover, the impact of the number of hops (N) of the N -FS F CFM on the s-order metrics, the burst error rate and maximum symbol rate are numerically evaluated and investigated. The derived s-order statistical results can be used to address the cooperative relay-assisted (RA) communications for vehicular systems. Monte-Carlo (M - C) simulations for the addressed statistical measures are developed in order to confirm the provided theoretical results.This work was supported in part by UC3M and the European Union's Horizon 2020 Programme under the Marie Sklodowska-Curie Grant through the CONEX-Plus Project under Agreement 801538; in part by the IRENE-EARTH Project under Grant PID2020-115323RB-C33/AEI/10.13039/501100011033; in part by ERDF and the Spanish Government Projects under Grant PID2019-106808RA-I00 AEI/FEDER, UE; in part by CDTI Cervera Project INTEGRA under Grant CER-20211031; in part by the Secretaria d'Universitats i Recerca de la Generalitat de Catalunya under Project 2017-SGR-00376 and Project Fem IoT under Grant 001-P-001662; in part by the European Commission Project CPSoSaware; and in part by the Cost Actions under Grant CA19111, Grant CA20120, and Grant CA16220.Publicad
Maximum entropy based analysis of a DS/SSMA diversity system
D.Ing.This thesis sets out to propose and analyze a cellular Direct Sequence Spread Spectrum Multiple Access (DSjSSMA) system for the Indoor Wireless Communication (IWC) Nakagami fading channel. The up- and downlink of the system implement Differential Phase Shift Keying (DPSK) and Coherent Phase Shift Keying (CPSK) as modulation schemes respectively, and are analyzed using Maximum Entropy (MaxEnt) principles due to its reliability and accuracy. As a means to enhance system capacity and performance, different forms of diversity are investigated; for the up- and downlink, respectively, RAKE reception and Maximum Ratio Combining (MRC) diversity together with Forward Error Control (FEC) coding are assumed. Further, the validity of the Gaussian Assumption (GA) is quantified and investigated under fading and non-fading conditions by calculating the missing information, using Minimum Relative Entropy (MRE) principles between the Inter- User Interference (IUI) distribution and a Gaussian distribution of equal variance
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