22,598 research outputs found
A Game Theoretic Analysis for Energy Efficient Heterogeneous Networks
Smooth and green future extension/scalability (e.g., from sparse to dense,
from small-area dense to large-area dense, or from normal-dense to super-dense)
is an important issue in heterogeneous networks. In this paper, we study energy
efficiency of heterogeneous networks for both sparse and dense two-tier small
cell deployments. We formulate the problem as a hierarchical (Stackelberg) game
in which the macro cell is the leader whereas the small cell is the follower.
Both players want to strategically decide on their power allocation policies in
order to maximize the energy efficiency of their registered users. A backward
induction method has been used to obtain a closed-form expression of the
Stackelberg equilibrium. It is shown that the energy efficiency is maximized
when only one sub-band is exploited for the players of the game depending on
their fading channel gains. Simulation results are presented to show the
effectiveness of the proposed scheme.Comment: 7 pages, 3 figures, in Wiopt 201
Data-driven Flood Emulation: Speeding up Urban Flood Predictions by Deep Convolutional Neural Networks
Computational complexity has been the bottleneck of applying physically-based
simulations on large urban areas with high spatial resolution for efficient and
systematic flooding analyses and risk assessments. To address this issue of
long computational time, this paper proposes that the prediction of maximum
water depth rasters can be considered as an image-to-image translation problem
where the results are generated from input elevation rasters using the
information learned from data rather than by conducting simulations, which can
significantly accelerate the prediction process. The proposed approach was
implemented by a deep convolutional neural network trained on flood simulation
data of 18 designed hyetographs on three selected catchments. Multiple tests
with both designed and real rainfall events were performed and the results show
that the flood predictions by neural network uses only 0.5 % of time comparing
with physically-based approaches, with promising accuracy and ability of
generalizations. The proposed neural network can also potentially be applied to
different but relevant problems including flood predictions for urban layout
planning
Minimization of Handoff Failure Probability for Next-Generation Wireless Systems
During the past few years, advances in mobile communication theory have
enabled the development and deployment of different wireless technologies,
complementary to each other. Hence, their integration can realize a unified
wireless system that has the best features of the individual networks.
Next-Generation Wireless Systems (NGWS) integrate different wireless systems,
each of which is optimized for some specific services and coverage area to
provide ubiquitous communications to the mobile users. In this paper, we
propose to enhance the handoff performance of mobile IP in wireless IP networks
by reducing the false handoff probability in the NGWS handoff management
protocol. Based on the information of false handoff probability, we analyze its
effect on mobile speed and handoff signaling delay.Comment: 16 Page
Coalitional Games with Overlapping Coalitions for Interference Management in Small Cell Networks
In this paper, we study the problem of cooperative interference management in
an OFDMA two-tier small cell network. In particular, we propose a novel
approach for allowing the small cells to cooperate, so as to optimize their
sum-rate, while cooperatively satisfying their maximum transmit power
constraints. Unlike existing work which assumes that only disjoint groups of
cooperative small cells can emerge, we formulate the small cells' cooperation
problem as a coalition formation game with overlapping coalitions. In this
game, each small cell base station can choose to participate in one or more
cooperative groups (or coalitions) simultaneously, so as to optimize the
tradeoff between the benefits and costs associated with cooperation. We study
the properties of the proposed overlapping coalition formation game and we show
that it exhibits negative externalities due to interference. Then, we propose a
novel decentralized algorithm that allows the small cell base stations to
interact and self-organize into a stable overlapping coalitional structure.
Simulation results show that the proposed algorithm results in a notable
performance advantage in terms of the total system sum-rate, relative to the
noncooperative case and the classical algorithms for coalitional games with
non-overlapping coalitions
Allocation of control and data channels for Large-Scale Wireless Sensor Networks
Both IEEE 802.15.4 and 802.15.4a standards allow for dynamic channel
allocation and use of multiple channels available at their physical layers but
its MAC protocols are designed only for single channel. Also, sensor's
transceivers such as CC2420 provide multiple channels and as shown in [1], [2]
and [3] channel switch latency of CC2420 transceiver is just about 200s.
In order to enhance both energy efficiency and to shorten end to end delay, we
propose, in this report, a spectrum-efficient frequency allocation schemes that
are able to statically assign control channels and dynamically reuse data
channels for Personal Area Networks (PANs) inside a Large-Scale WSN based on
UWB technology
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