2,242 research outputs found
Improved NOVSF-TM based Addressing and Energy Efficient Routing in ETR Protocol
A small WSN is a collection of micro-sensors. Sensors send or receive data to a sink node, which collect and processes it. The Tree-Routing (TR) protocol was initially designed for such network. TR uses strict parent-child links for data forwarding. Hence, it saves bandwidth and energy by preventing network from flooding path search messages. For a large network TR shows large hop-count and more energy consumption. The Enhanced-Tree-Routing (ETR) protocol implemented over TR has structured node address assignment scheme. It considers other one-hop neighbor links, along with parent-child links, for packet forwarding if, it is found to be the shortest path to sink. Such decision in ETR involves minimum computation energy. Instead ETR, the emerging demand for data intensive and energy2013;efficient applications, needs new or improved routing protocols. In this paper we have proposed Non-Blocking-Orthogonal-Vector Spreading- Factor-Time-Multiplexing (NOVSF-TM) technique for sensor node addressing and Mobile Sinks placement so as to improve ETR protocol. The addressing scheme of NOVSF TM is shorter than ETR. Mobile Sinks positioning, at feasible sites, helps reducing excessive hop-count. This eliminate excessive multi-hoping and save energy. Simulation result shows that NOVSFTM technique is more energy-efficient than ETR protocol
Networking - A Statistical Physics Perspective
Efficient networking has a substantial economic and societal impact in a
broad range of areas including transportation systems, wired and wireless
communications and a range of Internet applications. As transportation and
communication networks become increasingly more complex, the ever increasing
demand for congestion control, higher traffic capacity, quality of service,
robustness and reduced energy consumption require new tools and methods to meet
these conflicting requirements. The new methodology should serve for gaining
better understanding of the properties of networking systems at the macroscopic
level, as well as for the development of new principled optimization and
management algorithms at the microscopic level. Methods of statistical physics
seem best placed to provide new approaches as they have been developed
specifically to deal with non-linear large scale systems. This paper aims at
presenting an overview of tools and methods that have been developed within the
statistical physics community and that can be readily applied to address the
emerging problems in networking. These include diffusion processes, methods
from disordered systems and polymer physics, probabilistic inference, which
have direct relevance to network routing, file and frequency distribution, the
exploration of network structures and vulnerability, and various other
practical networking applications.Comment: (Review article) 71 pages, 14 figure
Algorithmic Aspects of Energy-Delay Tradeoff in Multihop Cooperative Wireless Networks
We consider the problem of energy-efficient transmission in delay constrained
cooperative multihop wireless networks. The combinatorial nature of cooperative
multihop schemes makes it difficult to design efficient polynomial-time
algorithms for deciding which nodes should take part in cooperation, and when
and with what power they should transmit. In this work, we tackle this problem
in memoryless networks with or without delay constraints, i.e., quality of
service guarantee. We analyze a wide class of setups, including unicast,
multicast, and broadcast, and two main cooperative approaches, namely: energy
accumulation (EA) and mutual information accumulation (MIA). We provide a
generalized algorithmic formulation of the problem that encompasses all those
cases. We investigate the similarities and differences of EA and MIA in our
generalized formulation. We prove that the broadcast and multicast problems
are, in general, not only NP hard but also o(log(n)) inapproximable. We break
these problems into three parts: ordering, scheduling and power control, and
propose a novel algorithm that, given an ordering, can optimally solve the
joint power allocation and scheduling problems simultaneously in polynomial
time. We further show empirically that this algorithm used in conjunction with
an ordering derived heuristically using the Dijkstra's shortest path algorithm
yields near-optimal performance in typical settings. For the unicast case, we
prove that although the problem remains NP hard with MIA, it can be solved
optimally and in polynomial time when EA is used. We further use our algorithm
to study numerically the trade-off between delay and power-efficiency in
cooperative broadcast and compare the performance of EA vs MIA as well as the
performance of our cooperative algorithm with a smart noncooperative algorithm
in a broadcast setting.Comment: 12 pages, 9 figure
A critical analysis of research potential, challenges and future directives in industrial wireless sensor networks
In recent years, Industrial Wireless Sensor Networks (IWSNs) have emerged as an important research theme with applications spanning a wide range of industries including automation, monitoring, process control, feedback systems and automotive. Wide scope of IWSNs applications ranging from small production units, large oil and gas industries to nuclear fission control, enables a fast-paced research in this field. Though IWSNs offer advantages of low cost, flexibility, scalability, self-healing, easy deployment and reformation, yet they pose certain limitations on available potential and introduce challenges on multiple fronts due to their susceptibility to highly complex and uncertain industrial environments. In this paper a detailed discussion on design objectives, challenges and solutions, for IWSNs, are presented. A careful evaluation of industrial systems, deadlines and possible hazards in industrial atmosphere are discussed. The paper also presents a thorough review of the existing standards and industrial protocols and gives a critical evaluation of potential of these standards and protocols along with a detailed discussion on available hardware platforms, specific industrial energy harvesting techniques and their capabilities. The paper lists main service providers for IWSNs solutions and gives insight of future trends and research gaps in the field of IWSNs
Design Aspects of An Energy-Efficient, Lightweight Medium Access Control Protocol for Wireless Sensor Networks
This document gives an overview of the most relevant design aspects of the lightweight medium access control (LMAC) protocol [16] for wireless sensor networks (WSNs). These aspects include selfconfiguring and localized operation of the protocol, time synchronization in multi-hop networks, network setup and strategies to reduce latency.\ud
The main goal in designing a MAC protocol for WSNs is to minimize energy waste - due to collisions of messages and idle listening - , while limiting latency and loss of data throughput. It is shown that the LMAC protocol performs well on energy-efficiency and delivery ratio [19] and can\ud
ensure a long-lived, self-configuring network of battery-powered wireless sensors.\ud
The protocol is based upon scheduled access, in which each node periodically gets a time slot, during which it is allowed to transmit. The protocol does not depend on central managers to assign time slots to nodes.\ud
WSNs are assumed to be multi-hop networks, which allows for spatial reuse of time slots, just like frequency reuse in GSM cells. In this document, we present a distributed algorithm that allows nodes to find unoccupied time slots, which can be used without causing collision or interference to other nodes. Each node takes one time slot in control to\ud
carry out its data transmissions. Latency is affected by the actual choice of controlled time slot. We present time slot choosing strategies, which ensure a low latency for the most common data traffic in WSNs: reporting of sensor readings to central sinks
Resource Allocation in Ad Hoc Networks
Unlike the centralized network, the ad hoc network does not have any central administrations and energy is constrained, e.g. battery, so the resource allocation plays a
very important role in efficiently managing the limited energy in ad hoc networks.
This thesis focuses on the resource allocation in ad hoc networks and aims to develop
novel techniques that will improve the network performance from different network
layers, such as the physical layer, Medium Access Control (MAC) layer and network
layer.
This thesis examines the energy utilization in High Speed Downlink Packet Access (HSDPA) systems at the physical layer. Two resource allocation techniques,
known as channel adaptive HSDPA and two-group HSDPA, are developed to improve the performance of an ad hoc radio system through reducing the residual
energy, which in turn, should improve the data rate in HSDPA systems. The channel adaptive HSDPA removes the constraint on the number of channels used for
transmissions. The two-group allocation minimizes the residual energy in HSDPA
systems and therefore enhances the physical data rates in transmissions due to adaptive modulations. These proposed approaches provide better data rate than rates
achieved with the current HSDPA type of algorithm.
By considering both physical transmission power and data rates for defining the
cost function of the routing scheme, an energy-aware routing scheme is proposed
in order to find the routing path with the least energy consumption. By focusing
on the routing paths with low energy consumption, computational complexity is
significantly reduced. The data rate enhancement achieved by two-group resource
allocation further reduces the required amount of energy per bit for each path. With
a novel load balancing technique, the information bits can be allocated to each path
in such that a way the overall amount of energy consumed is minimized.
After loading bits to multiple routing paths, an end-to-end delay minimization
solution along a routing path is developed through studying MAC distributed coordination function (DCF) service time. Furthermore, the overhead effect and the
related throughput reduction are studied. In order to enhance the network throughput at the MAC layer, two MAC DCF-based adaptive payload allocation approaches
are developed through introducing Lagrange optimization and studying equal data
transmission period
On the Security of the Automatic Dependent Surveillance-Broadcast Protocol
Automatic dependent surveillance-broadcast (ADS-B) is the communications
protocol currently being rolled out as part of next generation air
transportation systems. As the heart of modern air traffic control, it will
play an essential role in the protection of two billion passengers per year,
besides being crucial to many other interest groups in aviation. The inherent
lack of security measures in the ADS-B protocol has long been a topic in both
the aviation circles and in the academic community. Due to recently published
proof-of-concept attacks, the topic is becoming ever more pressing, especially
with the deadline for mandatory implementation in most airspaces fast
approaching.
This survey first summarizes the attacks and problems that have been reported
in relation to ADS-B security. Thereafter, it surveys both the theoretical and
practical efforts which have been previously conducted concerning these issues,
including possible countermeasures. In addition, the survey seeks to go beyond
the current state of the art and gives a detailed assessment of security
measures which have been developed more generally for related wireless networks
such as sensor networks and vehicular ad hoc networks, including a taxonomy of
all considered approaches.Comment: Survey, 22 Pages, 21 Figure
The Wireless Body Area Sensor Networks and Routing Strategies: Nomenclature and Review of Literature
WBASN is an effective solution that has been proposed in terms of improving the solutions and there are varied benefits that have been achieved from the usage of WBASN solutions in communication, healthcare domain. From the review of stats on rising number of wireless devices and solutions that are coming up which is embraced by the people as wearable devices, implants for medical diagnostic solutions, etc. reflect upon the growing demand for effective models. However, the challenge is about effective performance of such solutions with optimal efficiency. Due to certain intrinsic factors like numerous standards that are available, and also due to the necessity for identifying the best solutions that are based on application requirements. Some of the key issues that have to be considered in the process of WBASN are about the impacts that are taking place from the wireless medium, the lifetime of batteries in the WBASN devices and the other significant condition like the coexistence of the systems among varied other wireless networks that are constituted in the proximity. In this study, scores of models that has been proposed pertaining to MAC protocols for WBASN solutions has been reviewed to understand the efficacy of the existing systems, and a scope for process improvement has been explored for conducting in detail research and developing a solution
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