2,860 research outputs found
Overlaid Cellular and Mobile Ad Hoc Networks
In cellular systems using frequency division duplex, growing Internet
services cause unbalance of uplink and downlink traffic, resulting in poor
uplink spectrum utilization. Addressing this issue, this paper considers
overlaying an ad hoc network onto a cellular uplink network for improving
spectrum utilization and spatial reuse efficiency. Transmission capacities of
the overlaid networks are analyzed, which are defined as the maximum densities
of the ad hoc nodes and mobile users under an outage constraint. Using tools
from stochastic geometry, the capacity tradeoff curves for the overlaid
networks are shown to be linear. Deploying overlaid networks based on frequency
separation is proved to achieve higher network capacities than that based on
spatial separation. Furthermore, spatial diversity is shown to enhance network
capacities.Comment: 5 pages; submitted to IEEE ICCS 2008 (Guangzhou, P.R.China
User Attraction via Wireless Charging in Cellular Networks
A strong motivation of charging depleted battery can be an enabler for
network capacity increase. In this light we propose a spatial attraction
cellular network (SAN) consisting of macro cells overlaid with small cell base
stations that wirelessly charge user batteries. Such a network makes battery
depleting users move toward the vicinity of small cell base stations. With a
fine adjustment of charging power, this user spatial attraction (SA) improves
in spectral efficiency as well as load balancing. We jointly optimize both
enhancements thanks to SA, and derive the corresponding optimal charging power
in a closed form by using a stochastic geometric approach.Comment: to be presented in IEEE International Symposium on Modeling and
Optimization in Mobile, Ad Hoc and Wireless Networks (WiOpt) Workshop on
Green Networks (GREENNET) 2016, Arizona, USA (8 pages, 4 figures
Distributed SIR-Aware Opportunistic Access Control for D2D Underlaid Cellular Networks
In this paper, we propose a distributed interference and channel-aware
opportunistic access control technique for D2D underlaid cellular networks, in
which each potential D2D link is active whenever its estimated
signal-to-interference ratio (SIR) is above a predetermined threshold so as to
maximize the D2D area spectral efficiency. The objective of our SIR-aware
opportunistic access scheme is to provide sufficient coverage probability and
to increase the aggregate rate of D2D links by harnessing interference caused
by dense underlaid D2D users using an adaptive decision activation threshold.
We determine the optimum D2D activation probability and threshold, building on
analytical expressions for the coverage probabilities and area spectral
efficiency of D2D links derived using stochastic geometry. Specifically, we
provide two expressions for the optimal SIR threshold, which can be applied in
a decentralized way on each D2D link, so as to maximize the D2D area spectral
efficiency derived using the unconditional and conditional D2D success
probability respectively. Simulation results in different network settings show
the performance gains of both SIR-aware threshold scheduling methods in terms
of D2D link coverage probability, area spectral efficiency, and average sum
rate compared to existing channel-aware access schemes.Comment: 6 pages, 6 figures, to be presented at IEEE GLOBECOM 201
On Capacity and Delay of Multi-channel Wireless Networks with Infrastructure Support
In this paper, we propose a novel multi-channel network with infrastructure
support, called an MC-IS network, which has not been studied in the literature.
To the best of our knowledge, we are the first to study such an MC-IS network.
Our proposed MC-IS network has a number of advantages over three existing
conventional networks, namely a single-channel wireless ad hoc network (called
an SC-AH network), a multi-channel wireless ad hoc network (called an MC-AH
network) and a single-channel network with infrastructure support (called an
SC-IS network). In particular, the network capacity of our proposed MC-IS
network is times higher than that of an SC-AH network and an
MC-AH network and the same as that of an SC-IS network, where is the number
of nodes in the network. The average delay of our MC-IS network is times lower than that of an SC-AH network and an MC-AH network, and
times lower than the average delay of an SC-IS network, where
and denote the number of channels dedicated for infrastructure
communications and the number of interfaces mounted at each infrastructure
node, respectively. Our analysis on an MC-IS network equipped with
omni-directional antennas only has been extended to an MC-IS network equipped
with directional antennas only, which are named as an MC-IS-DA network. We show
that an MC-IS-DA network has an even lower delay of compared with an SC-IS network and our
MC-IS network. For example, when and , an
MC-IS-DA network can further reduce the delay by 24 times lower that of an
MC-IS network and reduce the delay by 288 times lower than that of an SC-IS
network.Comment: accepted, IEEE Transactions on Vehicular Technology, 201
PACE: Simple Multi-hop Scheduling for Single-radio 802.11-based Stub Wireless Mesh Networks
IEEE 802.11-based Stub Wireless Mesh Networks (WMNs) are a cost-effective and flexible solution to extend wired network infrastructures. Yet, they suffer from two major problems: inefficiency and unfairness. A number of approaches have been proposed to tackle these problems, but they are too restrictive, highly complex, or require time synchronization and modifications to the IEEE 802.11 MAC.
PACE is a simple multi-hop scheduling mechanism for Stub WMNs overlaid on the IEEE 802.11 MAC that jointly addresses the inefficiency and unfairness problems. It limits transmissions to a single mesh node at each time and ensures that each node has the opportunity to transmit a packet in each network-wide transmission round. Simulation results demonstrate that PACE can achieve optimal network capacity utilization and greatly outperforms state of the art CSMA/CA-based solutions as far as goodput, delay, and fairness are concerned
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