1,137 research outputs found
Spectroscopic studies of some iron complexes
Imperial Users onl
A Stochastic Geometric Analysis of Device-to-Device Communications Operating over Generalized Fading Channels
Device-to-device (D2D) communications are now considered as an integral part
of future 5G networks which will enable direct communication between user
equipment (UE) without unnecessary routing via the network infrastructure. This
architecture will result in higher throughputs than conventional cellular
networks, but with the increased potential for co-channel interference induced
by randomly located cellular and D2D UEs. The physical channels which
constitute D2D communications can be expected to be complex in nature,
experiencing both line-of-sight (LOS) and non-LOS (NLOS) conditions across
closely located D2D pairs. As well as this, given the diverse range of
operating environments, they may also be subject to clustering of the scattered
multipath contribution, i.e., propagation characteristics which are quite
dissimilar to conventional Rayeligh fading environments. To address these
challenges, we consider two recently proposed generalized fading models, namely
and , to characterize the fading behavior in D2D
communications. Together, these models encompass many of the most widely
encountered and utilized fading models in the literature such as Rayleigh, Rice
(Nakagami-), Nakagami-, Hoyt (Nakagami-) and One-Sided Gaussian. Using
stochastic geometry we evaluate the rate and bit error probability of D2D
networks under generalized fading conditions. Based on the analytical results,
we present new insights into the trade-offs between the reliability, rate, and
mode selection under realistic operating conditions. Our results suggest that
D2D mode achieves higher rates over cellular link at the expense of a higher
bit error probability. Through numerical evaluations, we also investigate the
performance gains of D2D networks and demonstrate their superiority over
traditional cellular networks.Comment: Submitted to IEEE Transactions on Wireless Communication
On the Sum of Fisher-Snedecor F Variates and its Application to Maximal-Ratio Combining
Capitalizing on the recently proposed Fisher-Snedecor F composite fading
model, in this letter, we investigate the sum of independent but not
identically distributed (i.n.i.d.) Fisher-Snedecor F variates. First, a novel
closed-form expression is derived for the moment generating function of the
instantaneous signal-to-noise ratio. Based on this, the corresponding
probability density function and cumulative distribution function of the sum of
i.n.i.d. Fisher- Snedecor F variates are derived, which are subsequently
employed in the analysis of multiple branch maximal-ratio combining (MRC).
Specifically, we investigate the impact of multipath and shadowed fading on the
outage probability and outage capacity of MRC based receivers. In addition, we
derive exact closed-form expressions for the average bit error rate of coherent
binary modulation schemes followed by an asymptotic analysis which provides
further insights into the effect of the system parameters on the overall
performance. Importantly, it is shown that the effect of multipath fading on
the system performance is more pronounced than that of shadowing.Comment: 5 pages, 3 figure
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