2,399 research outputs found
Low Power Dynamic Scheduling for Computing Systems
This paper considers energy-aware control for a computing system with two
states: "active" and "idle." In the active state, the controller chooses to
perform a single task using one of multiple task processing modes. The
controller then saves energy by choosing an amount of time for the system to be
idle. These decisions affect processing time, energy expenditure, and an
abstract attribute vector that can be used to model other criteria of interest
(such as processing quality or distortion). The goal is to optimize time
average system performance. Applications of this model include a smart phone
that makes energy-efficient computation and transmission decisions, a computer
that processes tasks subject to rate, quality, and power constraints, and a
smart grid energy manager that allocates resources in reaction to a time
varying energy price. The solution methodology of this paper uses the theory of
optimization for renewal systems developed in our previous work. This paper is
written in tutorial form and develops the main concepts of the theory using
several detailed examples. It also highlights the relationship between online
dynamic optimization and linear fractional programming. Finally, it provides
exercises to help the reader learn the main concepts and apply them to their
own optimizations. This paper is an arxiv technical report, and is a
preliminary version of material that will appear as a book chapter in an
upcoming book on green communications and networking.Comment: 26 pages, 10 figures, single spac
Cross-layer design of multi-hop wireless networks
MULTI -hop wireless networks are usually defined as a collection of nodes
equipped with radio transmitters, which not only have the capability to
communicate each other in a multi-hop fashion, but also to route each others’ data
packets. The distributed nature of such networks makes them suitable for a variety of
applications where there are no assumed reliable central entities, or controllers, and
may significantly improve the scalability issues of conventional single-hop wireless
networks.
This Ph.D. dissertation mainly investigates two aspects of the research issues
related to the efficient multi-hop wireless networks design, namely: (a) network
protocols and (b) network management, both in cross-layer design paradigms to
ensure the notion of service quality, such as quality of service (QoS) in wireless mesh
networks (WMNs) for backhaul applications and quality of information (QoI) in
wireless sensor networks (WSNs) for sensing tasks. Throughout the presentation of
this Ph.D. dissertation, different network settings are used as illustrative examples,
however the proposed algorithms, methodologies, protocols, and models are not
restricted in the considered networks, but rather have wide applicability.
First, this dissertation proposes a cross-layer design framework integrating
a distributed proportional-fair scheduler and a QoS routing algorithm, while using
WMNs as an illustrative example. The proposed approach has significant performance
gain compared with other network protocols. Second, this dissertation proposes
a generic admission control methodology for any packet network, wired and
wireless, by modeling the network as a black box, and using a generic mathematical
0. Abstract 3
function and Taylor expansion to capture the admission impact. Third, this dissertation
further enhances the previous designs by proposing a negotiation process,
to bridge the applications’ service quality demands and the resource management,
while using WSNs as an illustrative example. This approach allows the negotiation
among different service classes and WSN resource allocations to reach the optimal
operational status. Finally, the guarantees of the service quality are extended to
the environment of multiple, disconnected, mobile subnetworks, where the question
of how to maintain communications using dynamically controlled, unmanned data
ferries is investigated
Energy Harvesting Wireless Communications: A Review of Recent Advances
This article summarizes recent contributions in the broad area of energy
harvesting wireless communications. In particular, we provide the current state
of the art for wireless networks composed of energy harvesting nodes, starting
from the information-theoretic performance limits to transmission scheduling
policies and resource allocation, medium access and networking issues. The
emerging related area of energy transfer for self-sustaining energy harvesting
wireless networks is considered in detail covering both energy cooperation
aspects and simultaneous energy and information transfer. Various potential
models with energy harvesting nodes at different network scales are reviewed as
well as models for energy consumption at the nodes.Comment: To appear in the IEEE Journal of Selected Areas in Communications
(Special Issue: Wireless Communications Powered by Energy Harvesting and
Wireless Energy Transfer
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