2,291 research outputs found
Modeling and Analysis of K-Tier Downlink Heterogeneous Cellular Networks
Cellular networks are in a major transition from a carefully planned set of
large tower-mounted base-stations (BSs) to an irregular deployment of
heterogeneous infrastructure elements that often additionally includes micro,
pico, and femtocells, as well as distributed antennas. In this paper, we
develop a tractable, flexible, and accurate model for a downlink heterogeneous
cellular network (HCN) consisting of K tiers of randomly located BSs, where
each tier may differ in terms of average transmit power, supported data rate
and BS density. Assuming a mobile user connects to the strongest candidate BS,
the resulting Signal-to-Interference-plus-Noise-Ratio (SINR) is greater than 1
when in coverage, Rayleigh fading, we derive an expression for the probability
of coverage (equivalently outage) over the entire network under both open and
closed access, which assumes a strikingly simple closed-form in the high SINR
regime and is accurate down to -4 dB even under weaker assumptions. For
external validation, we compare against an actual LTE network (for tier 1) with
the other K-1 tiers being modeled as independent Poisson Point Processes. In
this case as well, our model is accurate to within 1-2 dB. We also derive the
average rate achieved by a randomly located mobile and the average load on each
tier of BSs. One interesting observation for interference-limited open access
networks is that at a given SINR, adding more tiers and/or BSs neither
increases nor decreases the probability of coverage or outage when all the
tiers have the same target-SINR.Comment: IEEE Journal on Selected Areas in Communications, vol. 30, no. 3, pp.
550 - 560, Apr. 201
A New Cell Association Scheme In Heterogeneous Networks
Cell association scheme determines which base station (BS) and mobile user
(MU) should be associated with and also plays a significant role in determining
the average data rate a MU can achieve in heterogeneous networks. However, the
explosion of digital devices and the scarcity of spectra collectively force us
to carefully re-design cell association scheme which was kind of taken for
granted before. To address this, we develop a new cell association scheme in
heterogeneous networks based on joint consideration of the
signal-to-interference-plus-noise ratio (SINR) which a MU experiences and the
traffic load of candidate BSs1. MUs and BSs in each tier are modeled as several
independent Poisson point processes (PPPs) and all channels experience
independently and identically distributed ( i.i.d.) Rayleigh fading. Data rate
ratio and traffic load ratio distributions are derived to obtain the tier
association probability and the average ergodic MU data rate. Through numerical
results, We find that our proposed cell association scheme outperforms cell
range expansion (CRE) association scheme. Moreover, results indicate that
allocating small sized and high-density BSs will improve spectral efficiency if
using our proposed cell association scheme in heterogeneous networks.Comment: Accepted by IEEE ICC 2015 - Next Generation Networking Symposiu
Downlink Coverage Analysis in a Heterogeneous Cellular Network
In this paper, we consider the downlink signal-to-interference-plus-noise
ratio (SINR) analysis in a heterogeneous cellular network with K tiers. Each
tier is characterized by a base-station (BS) arrangement according to a
homogeneous Poisson point process with certain BS density, transmission power,
random shadow fading factors with arbitrary distribution, arbitrary path-loss
exponent and a certain bias towards admitting the mobile-station (MS). The MS
associates with the BS that has the maximum SINR under the open access cell
association scheme. For such a general setting, we provide an analytical
characterization of the coverage probability at the MS.Comment: 6 pages, 5 figures, submitted to IEEE Globecom 2012 - Wireless
Communications Symposium on Apr 2, 201
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