913 research outputs found
Delay Minimizing User Association in Cellular Networks via Hierarchically Well-Separated Trees
We study downlink delay minimization within the context of cellular user
association policies that map mobile users to base stations. We note the delay
minimum user association problem fits within a broader class of network utility
maximization and can be posed as a non-convex quadratic program. This
non-convexity motivates a split quadratic objective function that captures the
original problem's inherent tradeoff: association with a station that provides
the highest signal-to-interference-plus-noise ratio (SINR) vs. a station that
is least congested. We find the split-term formulation is amenable to
linearization by embedding the base stations in a hierarchically well-separated
tree (HST), which offers a linear approximation with constant distortion. We
provide a numerical comparison of several problem formulations and find that
with appropriate optimization parameter selection, the quadratic reformulation
produces association policies with sum delays that are close to that of the
original network utility maximization. We also comment on the more difficult
problem when idle base stations (those without associated users) are
deactivated.Comment: 6 pages, 5 figures. Submitted on 2013-10-03 to the 2015 IEEE
International Conference on Communications (ICC). Accepted on 2015-01-09 to
the 2015 IEEE International Conference on Communications (ICC
On the Performance of Multi-tier Heterogeneous Cellular Networks with Idle Mode Capability
This paper studies the impact of the base station (BS) idle mode capability
(IMC) on the network performance of multi-tier and dense heterogeneous cellular
networks (HCNs). Different from most existing works that investigated network
scenarios with an infinite number of user equipments (UEs), we consider a more
practical setup with a finite number of UEs in our analysis. More specifically,
we derive the probability of which BS tier a typical UE should associate to and
the expression of the activated BS density in each tier. Based on such results,
analytical expressions for the coverage probability and the area spectral
efficiency (ASE) in each tier are also obtained. The impact of the IMC on the
performance of all BS tiers is shown to be significant. In particular, there
will be a surplus of BSs when the BS density in each tier exceeds the UE
density, and the overall coverage probability as well as the ASE continuously
increase when the BS IMC is applied. Such finding is distinctively different
from that in existing work. Thus, our result sheds new light on the design and
deployment of the future 5G HCNs.Comment: conference submissio
EVEREST IST - 2002 - 00185 : D23 : final report
Deliverable pĂşblic del projecte europeu EVERESTThis deliverable constitutes the final report of the project IST-2002-001858 EVEREST. After its successful completion, the project presents this document that firstly summarizes the context, goal and the approach objective of the project. Then it presents a concise summary of the major goals and results, as well as highlights the most valuable lessons derived form the project work. A list of deliverables and publications is included in the annex.Postprint (published version
- …