2,068 research outputs found
A Comprehensive Framework for Performance Analysis of Cooperative Multi-Hop Wireless Systems over Log-Normal Fading Channels
International audienceIn this paper, we propose a comprehensive framework for performance analysis of multi–hop multi–branch wireless communication systems over Log–Normal fading channels. The framework allows to estimate the performance of Amplify and Forward (AF) relay methods for both Channel State Information (CSI–) assisted relays, and fixed–gain relays. In particular, the contribution of this paper is twofold: i) first of all, by relying on the Gauss Quadrature Rule (GQR) representation of the Moment Generation Function (MGF) for a Log–Normal distribution, we develop accurate formulas for important performance indexes whose accuracy can be estimated a priori and just depends on GQR numerical integration errors; ii) then, in order to simplify the computational burden of the former framework for some system setups, we propose various approximations, which are based on the Improved Schwartz–Yeh (I–SY) method. We show with numerical and simulation results that the proposed approximations provide a good trade–off between accuracy and complexity for both Selection Combining (SC) and Maximal Ratio Combining (MRC) cooperative diversity methods
Diversity, Coding, and Multiplexing Trade-Off of Network-Coded Cooperative Wireless Networks
In this paper, we study the performance of network-coded cooperative
diversity systems with practical communication constraints. More specifically,
we investigate the interplay between diversity, coding, and multiplexing gain
when the relay nodes do not act as dedicated repeaters, which only forward data
packets transmitted by the sources, but they attempt to pursue their own
interest by forwarding packets which contain a network-coded version of
received and their own data. We provide a very accurate analysis of the Average
Bit Error Probability (ABEP) for two network topologies with three and four
nodes, when practical communication constraints, i.e., erroneous decoding at
the relays and fading over all the wireless links, are taken into account.
Furthermore, diversity and coding gain are studied, and advantages and
disadvantages of cooperation and binary Network Coding (NC) are highlighted.
Our results show that the throughput increase introduced by NC is offset by a
loss of diversity and coding gain. It is shown that there is neither a coding
nor a diversity gain for the source node when the relays forward a
network-coded version of received and their own data. Compared to other results
available in the literature, the conclusion is that binary NC seems to be more
useful when the relay nodes act only on behalf of the source nodes, and do not
mix their own packets to the received ones. Analytical derivation and findings
are substantiated through extensive Monte Carlo simulations.Comment: IEEE International Conference on Communications (ICC), 2012. Accepted
for publication and oral presentatio
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
Average Rate of Downlink Heterogeneous Cellular Networks over Generalized Fading Channels - A Stochastic Geometry Approach
In this paper, we introduce an analytical framework to compute the average
rate of downlink heterogeneous cellular networks. The framework leverages
recent application of stochastic geometry to other-cell interference modeling
and analysis. The heterogeneous cellular network is modeled as the
superposition of many tiers of Base Stations (BSs) having different transmit
power, density, path-loss exponent, fading parameters and distribution, and
unequal biasing for flexible tier association. A long-term averaged maximum
biased-received-power tier association is considered. The positions of the BSs
in each tier are modeled as points of an independent Poisson Point Process
(PPP). Under these assumptions, we introduce a new analytical methodology to
evaluate the average rate, which avoids the computation of the Coverage
Probability (Pcov) and needs only the Moment Generating Function (MGF) of the
aggregate interference at the probe mobile terminal. The distinguishable
characteristic of our analytical methodology consists in providing a tractable
and numerically efficient framework that is applicable to general fading
distributions, including composite fading channels with small- and mid-scale
fluctuations. In addition, our method can efficiently handle correlated
Log-Normal shadowing with little increase of the computational complexity. The
proposed MGF-based approach needs the computation of either a single or a
two-fold numerical integral, thus reducing the complexity of Pcov-based
frameworks, which require, for general fading distributions, the computation of
a four-fold integral.Comment: Accepted for publication in IEEE Transactions on Communications, to
appea
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