247 research outputs found
A New Formula for the BER of Binary Modulations with Dual-Branch Selection over Generalized-K Composite Fading Channels
Error performance is one of the main performance measures and derivation of
its closed-form expression has proved to be quite involved for certain systems.
In this letter, a unified closed-form expression, applicable to different
binary modulation schemes, for the bit error rate of dual-branch selection
diversity based systems undergoing independent but not necessarily identically
distributed generalized-K fading is derived in terms of the extended
generalized bivariate Meijer G-function.Comment: Diversity schemes, selection combining, dual-branch selection
diversity, binary modulation schemes, generalized-K (GK) model, composite
fading, bit error rate (BER), and Meijer G-function distributio
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
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
Performance analysis of mixed Nakagami- m and Gamma–Gamma dual-hop FSO transmission systems
In this paper, we carry out a unified performance analysis of a dual-hop relay system over the asymmetric links composed of both radio-frequency (RF) and unified free-space optical (FSO) links under the effect of pointing errors. Both fixed and variable gain relay systems are studied. The RF link is modeled by the Nakagami-m 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). In particular, we derive new unified closed-form expressions for the cumulative distribution function, the probability density function, the moment generating function (MGF), and the moments of the end-to-end signal-to-noise ratio (SNR) 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 (OP), the higher order amount of fading, and the average bit error rate (BER) of a variety of binary modulations in terms of the Meijer's G function. Furthermore, an exact closed-form expression of the end-to-end ergodic capacity is derived in terms of the bivariate G function. Additionally, by using the asymptotic expansion of the Meijer's G function at the high-SNR regime, we derive new asymptotic results for the OP, the MGF, and the average BER in terms of simple elementary functions
On the performance of a mixed RF/MIMO FSO variable gain dual-hop transmission system
In this work, we propose a mixed radio frequency (RF) and multiple-input-multiple-output (MIMO) free-space optical (FSO) system based on a variable-gain dual-hop relay transmission scheme. The RF channel is modeled by Rayleigh distribution and Gamma–Gamma turbulence distribution is adopted for the MIMO FSO link, which accounts for the equal gain combining diversity technique. Moreover, new closed-form mathematical formulas are obtained including the cumulative distribution function, probability density function, moment generating function, and moments of equivalent signal-to-noise ratio of the dual-hop relay system based on Meijer’s G function. As such, we derive the novel analytical expressions of the outage probability, the higher-order fading, and the average bit error rate for a range of modulations in terms of Meijer’s G function. Furthermore, the exact closed-form formula of the ergodic capacity is derived based on the bivariate Meijer’s G function. The evaluation and simulation are provided for system performance, and the effect of spatial diversity technique is discussed as well
Energy Detection of Unknown Signals over Cascaded Fading Channels
Energy detection is a favorable mechanism in several applications relating to
the identification of deterministic unknown signals such as in radar systems
and cognitive radio communications. The present work quantifies the detrimental
effects of cascaded multipath fading on energy detection and investigates the
corresponding performance capability. A novel analytic solution is firstly
derived for a generic integral that involves a product of the Meijer
function, the Marcum function and arbitrary power terms. This solution
is subsequently employed in the derivation of an exact closed-form expression
for the average probability of detection of unknown signals over *Rayleigh
channels. The offered results are also extended to the case of square-law
selection, which is a relatively simple and effective diversity method. It is
shown that the detection performance is considerably degraded by the number of
cascaded channels and that these effects can be effectively mitigated by a
non-substantial increase of diversity branches.Comment: 12 page
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