234 research outputs found
Dual-hop transmissions with fixed-gain relays over Generalized-Gamma fading channels
In this paper, a study on the end-to-end performance of dual-hop wireless communication systems equipped with fixed-gain relays and operating over Generalized-Gamma (GG) fading channels is presented. A novel closed form expression for the moments of the end-to-end signal-to-noise ratio (SNR) is derived. The average bit error probability for coherent and non-coherent modulation schemes as well as the end-to-end outage probability of the considered system are also studied. Extensive numerically evaluated and computer simulations results are presented that verify the accuracy of the proposed mathematical analysis.\u
Outage Probability of Dual-Hop Selective AF With Randomly Distributed and Fixed Interferers
The outage probability performance of a dual-hop amplify-and-forward
selective relaying system with global relay selection is analyzed for
Nakagami- fading channels in the presence of multiple interferers at both
the relays and the destination. Two different cases are considered. In the
first case, the interferers are assumed to have random number and locations.
Outage probability using the generalized Gamma approximation (GGA) in the form
of one-dimensional integral is derived. In the second case, the interferers are
assumed to have fixed number and locations. Exact outage probability in the
form of one-dimensional integral is derived. For both cases, closed-form
expressions of lower bounds and asymptotic expressions for high
signal-to-interference-plus-noise ratio are also provided. Simplified
closed-form expressions of outage probability for special cases (e.g., dominant
interferences, i.i.d. interferers, Rayleigh distributed signals) are studied.
Numerical results are presented to show the accuracy of our analysis by
examining the effects of the number and locations of interferers on the outage
performances of both AF systems with random and fixed interferers.Comment: 35 pages, 11 figures, accepted with minor revisions for publication
as a regular paper in the IEEE Transactions on Vehicular Technology on
21/09/201
Level Crossing Rate and Average Fade Duration of the Multihop Rayleigh Fading Channel
We present a novel analytical framework for the evaluation of important
second order statistical parameters, as the level crossing rate (LCR) and the
average fade duration (AFD) of the amplify-and-forward multihop Rayleigh fading
channel. More specifically, motivated by the fact that this channel is a
cascaded one, which can be modelled as the product of N fading amplitudes, we
derive novel analytical expressions for the average LCR and AFD of the product
of N Rayleigh fading envelopes, or of the recently so-called N*Rayleigh
channel. Furthermore, we derive simple and efficient closed-form approximations
to the aforementioned parameters, using the multivariate Laplace approximation
theorem. It is shown that our general results reduce to the specific dual-hop
case, previously published. Numerical and computer simulation examples verify
the accuracy of the presented mathematical analysis and show the tightness of
the proposed approximations
On the Second Order Statistics of the Multihop Rayleigh Fading Channel
Second order statistics provides a dynamic representation of a fading channel
and plays an important role in the evaluation and design of the wireless
communication systems. In this paper, we present a novel analytical framework
for the evaluation of important second order statistical parameters, as the
level crossing rate (LCR) and the average fade duration (AFD) of the
amplify-and-forward multihop Rayleigh fading channel. More specifically,
motivated by the fact that this channel is a cascaded one and can be modeled as
the product of N fading amplitudes, we derive novel analytical expressions for
the average LCR and the AFD of the product of N Rayleigh fading envelopes (or
of the recently so-called N*Rayleigh channel). Furthermore, we derive simple
and efficient closed-form approximations to the aforementioned parameters,
using the multivariate Laplace approximation theorem. It is shown that our
general results reduce to the corresponding ones of the specific dual-hop case,
previously published. Numerical and computer simulation examples verify the
accuracy of the presented mathematical analysis and show the tightness of the
proposed approximations
Unified Performance Analysis of Mixed Line of Sight RF-FSO Fixed Gain Dual-Hop Transmission Systems
In this work, we carry out a unified performance analysis of a dual-hop fixed
gain relay system over asymmetric links composed of both radio-frequency (RF)
and unified free-space optics (FSO) under the effect of pointing errors. The RF
link is modeled by the Nakagami- fading channel and the FSO link by the
Gamma-Gamma fading channel subject to both types of detection techniques (i.e.
heterodyne detection and intensity modulation with direct detection (IM/DD)).
In particular, we derive new unified closed-form expressions for the cumulative
distribution function, the probability density function, the moment generation
function, and the moments of the end-to-end signal-to-noise ratio of these
systems in terms of the Meijer's G function. Based on these formulas, we offer
exact closed-form expressions for the outage probability, the higher-order
amount of fading, and the average bit-error rate of a variety of binary
modulations in terms of the Meijer's G function. Further, an exact closed-form
expression for the end-to-end ergodic capacity for the Nakagami--unified FSO
relay links is derived in terms of the bivariate G function. All the given
results are verified via Computer-based Monte-Carlo simulations
Impact of Pointing Errors on the Performance of Mixed RF/FSO Dual-Hop Transmission Systems
In this work, the performance analysis of a dual-hop relay transmission
system composed of asymmetric radio-frequency (RF)/free-space optical (FSO)
links with pointing errors is presented. More specifically, we build on the
system model presented in [1] to derive new exact closed-form expressions for
the cumulative distribution function, probability density function, moment
generating function, and moments of the end-to-end signal-to-noise ratio in
terms of the Meijer's G function. We then capitalize on these results to offer
new exact closed-form expressions for the higher-order amount of fading,
average error rate for binary and M-ary modulation schemes, and the ergodic
capacity, all in terms of Meijer's G functions. Our new analytical results were
also verified via computer-based Monte-Carlo simulation results.Comment: 6 pages, 3 figure
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