7,432 research outputs found
Security and Privacy Issues in Wireless Mesh Networks: A Survey
This book chapter identifies various security threats in wireless mesh
network (WMN). Keeping in mind the critical requirement of security and user
privacy in WMNs, this chapter provides a comprehensive overview of various
possible attacks on different layers of the communication protocol stack for
WMNs and their corresponding defense mechanisms. First, it identifies the
security vulnerabilities in the physical, link, network, transport, application
layers. Furthermore, various possible attacks on the key management protocols,
user authentication and access control protocols, and user privacy preservation
protocols are presented. After enumerating various possible attacks, the
chapter provides a detailed discussion on various existing security mechanisms
and protocols to defend against and wherever possible prevent the possible
attacks. Comparative analyses are also presented on the security schemes with
regards to the cryptographic schemes used, key management strategies deployed,
use of any trusted third party, computation and communication overhead involved
etc. The chapter then presents a brief discussion on various trust management
approaches for WMNs since trust and reputation-based schemes are increasingly
becoming popular for enforcing security in wireless networks. A number of open
problems in security and privacy issues for WMNs are subsequently discussed
before the chapter is finally concluded.Comment: 62 pages, 12 figures, 6 tables. This chapter is an extension of the
author's previous submission in arXiv submission: arXiv:1102.1226. There are
some text overlaps with the previous submissio
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
RTXP : A Localized Real-Time Mac-Routing Protocol for Wireless Sensor Networks
Protocols developed during the last years for Wireless Sensor Networks (WSNs)
are mainly focused on energy efficiency and autonomous mechanisms (e.g.
self-organization, self-configuration, etc). Nevertheless, with new WSN
applications, appear new QoS requirements such as time constraints. Real-time
applications require the packets to be delivered before a known time bound
which depends on the application requirements. We particularly focus on
applications which consist in alarms sent to the sink node. We propose
Real-Time X-layer Protocol (RTXP), a real-time communication protocol. To the
best of our knowledge, RTXP is the first MAC and routing real-time
communication protocol that is not centralized, but instead relies only on
local information. The solution is cross-layer (X-layer) because it allows to
control the delays due to MAC and Routing layers interactions. RTXP uses a
suited hop-count-based Virtual Coordinate System which allows deterministic
medium access and forwarder selection. In this paper we describe the protocol
mechanisms. We give theoretical bound on the end-to-end delay and the capacity
of the protocol. Intensive simulation results confirm the theoretical
predictions and allow to compare with a real-time centralized solution. RTXP is
also simulated under harsh radio channel, in this case the radio link
introduces probabilistic behavior. Nevertheless, we show that RTXP it performs
better than a non-deterministic solution. It thus advocates for the usefulness
of designing real-time (deterministic) protocols even for highly unreliable
networks such as WSNs
Wireless industrial monitoring and control networks: the journey so far and the road ahead
While traditional wired communication technologies have played a crucial role in industrial monitoring and control networks over the past few decades, they are increasingly proving to be inadequate to meet the highly dynamic and stringent demands of today’s industrial applications, primarily due to the very rigid nature of wired infrastructures. Wireless technology, however, through its increased pervasiveness, has the potential to revolutionize the industry, not only by mitigating the problems faced by wired solutions, but also by introducing a completely new class of applications. While present day wireless technologies made some preliminary inroads in the monitoring domain, they still have severe limitations especially when real-time, reliable distributed control operations are concerned. This article provides the reader with an overview of existing wireless technologies commonly used in the monitoring and control industry. It highlights the pros and cons of each technology and assesses the degree to which each technology is able to meet the stringent demands of industrial monitoring and control networks. Additionally, it summarizes mechanisms proposed by academia, especially serving critical applications by addressing the real-time and reliability requirements of industrial process automation. The article also describes certain key research problems from the physical layer communication for sensor networks and the wireless networking perspective that have yet to be addressed to allow the successful use of wireless technologies in industrial monitoring and control networks
Adaptive Duty Cycling MAC Protocols Using Closed-Loop Control for Wireless Sensor Networks
The fundamental design goal of wireless sensor MAC protocols is to minimize unnecessary power consumption of the sensor nodes, because of its stringent resource constraints and ultra-power limitation. In existing MAC protocols in wireless sensor networks (WSNs), duty cycling, in which each node periodically cycles between the active and sleep states, has been introduced to reduce unnecessary energy consumption. Existing MAC schemes, however, use a fixed duty cycling regardless of multi-hop communication and traffic fluctuations. On the other hand, there is a tradeoff between energy efficiency and delay caused by duty cycling mechanism in multi-hop communication and existing MAC approaches only tend to improve energy efficiency with sacrificing data delivery delay. In this paper, we propose two different MAC schemes (ADS-MAC and ELA-MAC) using closed-loop control in order to achieve both energy savings and minimal delay in wireless sensor networks. The two proposed MAC schemes, which are synchronous and asynchronous approaches, respectively, utilize an adaptive timer and a successive preload frame with closed-loop control for adaptive duty cycling. As a result, the analysis and the simulation results show that our schemes outperform existing schemes in terms of energy efficiency and delivery delay
The Bus Goes Wireless: Routing-Free Data Collection with QoS Guarantees in Sensor Networks
Abstract—We present the low-power wireless bus (LWB), a new communication paradigm for QoS-aware data collection in lowpower sensor networks. The LWB maps all communication onto network floods by using Glossy, an efficient flooding architecture for wireless sensor networks. Therefore, unlike current solutions, the LWB requires no information of the network topology, and inherently supports networks with mobile nodes and multiple data sinks. A LWB prototype implemented in Contiki guarantees bounded end-to-end communication delay and duplicate-free, inorder packet delivery—key QoS requirements in many control and mission-critical applications. Experiments on two testbeds demonstrate that the LWB prototype outperforms state-of-theart data collection and link layer protocols, in terms of reliability and energy efficiency. For instance, we measure an average radio duty cycle of 1.69 % and an overall data yield of 99.97 % in a typical data collection scenario with 85 sensor nodes on Twist. I
Feedback Control Goes Wireless: Guaranteed Stability over Low-power Multi-hop Networks
Closing feedback loops fast and over long distances is key to emerging
applications; for example, robot motion control and swarm coordination require
update intervals of tens of milliseconds. Low-power wireless technology is
preferred for its low cost, small form factor, and flexibility, especially if
the devices support multi-hop communication. So far, however, feedback control
over wireless multi-hop networks has only been shown for update intervals on
the order of seconds. This paper presents a wireless embedded system that tames
imperfections impairing control performance (e.g., jitter and message loss),
and a control design that exploits the essential properties of this system to
provably guarantee closed-loop stability for physical processes with linear
time-invariant dynamics. Using experiments on a cyber-physical testbed with 20
wireless nodes and multiple cart-pole systems, we are the first to demonstrate
and evaluate feedback control and coordination over wireless multi-hop networks
for update intervals of 20 to 50 milliseconds.Comment: Accepted final version to appear in: 10th ACM/IEEE International
Conference on Cyber-Physical Systems (with CPS-IoT Week 2019) (ICCPS '19),
April 16--18, 2019, Montreal, QC, Canad
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