53 research outputs found
Technical Rate of Substitution of Spectrum in Future Mobile Broadband Provisioning
Dense deployment of base stations (BSs) and multi-antenna techniques are
considered key enablers for future mobile networks. Meanwhile, spectrum sharing
techniques and utilization of higher frequency bands make more bandwidth
available. An important question for future system design is which element is
more effective than others. In this paper, we introduce the concept of
technical rate of substitution (TRS) from microeconomics and study the TRS of
spectrum in terms of BS density and antenna number per BS. Numerical results
show that TRS becomes higher with increasing user data rate requirement,
suggesting that spectrum is the most effective means of provisioning extremely
fast mobile broadband.Comment: 5 pages, 5 figures, conferenc
Worst-case User Analysis in Poisson Voronoi Cells
In this letter, we focus on the performance of a worst-case mobile user (MU)
in the downlink cellular network. We derive the coverage probability and the
spectral efficiency of the worst-case MU using stochastic geometry. Through
analytical and numerical results, we draw out interesting insights that the
coverage probability and the spectral efficiency of the worst-case MU decrease
down to 23% and 19% of those of a typical MU, respectively. By applying a
coordinated scheduling (CS) scheme, we also investigate how much the
performance of the worst-case MU is improved.Comment: Accepted, IEEE Communications Letter
Asymptotic Behavior of Ultra-Dense Cellular Networks and Its Economic Impact
This paper investigates the relationship between base station (BS) density
and average spectral efficiency (SE) in the downlink of a cellular network.
This relationship has been well known for sparse deployment, i.e. when the
number of BSs is small compared to the number of users. In this case the SE is
independent of BS density. As BS density grows, on the other hand, it has
previously been shown that increasing the BS density increases the SE, but no
tractable form for the SE-BS density relationship has yet been derived. In this
paper we derive such a closed-form result that reveals the SE is asymptotically
a logarithmic function of BS density as the density grows. Further, we study
the impact of this result on the network operator's profit when user demand
varies, and derive the profit maximizing BS density and the optimal amount of
spectrum to be utilized in closed forms. In addition, we provide deployment
planning guidelines that will aid the operator in his decision if he should
invest in densifying his network or in acquiring more spectrum.Comment: This paper will appear in Proc. IEEE Global Commun. Conf. (GLOBECOM)
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Exploiting Frequency and Spatial Dimensions in Small Cell Wireless Networks
This paper examines the efficiency of spatial and frequency dimensions in
serving multiple users in the downlink of a small cell wireless network with
randomly deployed access points. For this purpose, the stochastic geometry
framework is incorporated, taking into account the user distribution within
each cell and the effect of sharing the available system resources to multiple
users. An analysis of performance in terms of signal-to-interference-ratio and
achieved user rate is provided that holds under the class of non-cooperative
multiple access schemes. In order to obtain concrete results, two simple
instances of multiple access schemes are considered. It is shown that
performance depends critically on both the availability of frequency and/or
spatial dimensions as well as the way they are employed. In particular,
increasing the number of available frequency dimensions alone is beneficial for
users experiencing large interference, whereas increasing spatial dimensions
without employing frequency dimensions degrades performance. However, best
performance is achieved when both dimensions are combined in serving the users.Comment: IEEE WCNC '1
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