155 research outputs found
Efficient Retransmission QoS-Aware MAC Scheme in Wireless Sensor Networks
In this paper, an Efficient Retransmission Random Access Protocol (ERRAP) is designed that combines scheme of collision avoidance and energy management for low-cost, short-range wireless radios and low-energy sensor nodes applications. This protocol focuses on efficient Media Access Control (MAC) schemes to provide autonomous Quality of Service (QoS) to the sensor nodes in one-hop QoS retransmission group in WSNs where the source nodes do not have receiver circuits. These sensor nodes can only transmit data to a destination node, but cannot receive acknowledgement or control signals from the destination node. The proposed scheme ERRAP provides QoS to the nodes which work independently on predefined time by allowing them to transmit each packet an optimal number of times within a given period. Our simulation results demonstrate the superiority of ERRAP scheme which increases the delivery probability and reduces the energy consumption
QOS GROUP BASED OPTIMAL RETRANSMISSION MEDIUM ACCESS PROTOCOL FOR WIRELESS SENSOR NETWORKS
This paper presents, a Group Based Optimal Retransmission Medium Access (GORMA) Protocol is designed that combines protocol of Collision Avoidance (CA) and energy management for low-cost, shortrange, low-data rate and low-energy sensor nodes applications in environment monitoring, agriculture, industrial plants etc. In this paper, the GORMA protocol focuses on efficient MAC protocol to provide autonomous Quality of Service (QoS) to the sensor nodes in one-hop QoS retransmission group and two QoS groups in WSNs where the source nodes do not have receiver circuits. Hence, they can only transmit
data to a sink node, but cannot receive any control signals from the sink node. The proposed protocol
GORMA provides QoS to the nodes which work independently on predefined time by allowing them to transmit each packet an optimal number of times within a given period. Our simulation results shows that the performance of GORMA protocol, which maximize the delivery probability of one-hop QoS group and two QoS groups and minimize the energy consumption
IEEE 802.15.4: a Federating Communication Protocol for Time-Sensitive Wireless Sensor Networks
Wireless Sensor Networks (WSNs) have been attracting increasing interests for developing a new
generation of embedded systems with great potential for many applications such as surveillance,
environment monitoring, emergency medical response and home automation. However, the
communication paradigms in WSNs differ from the ones attributed to traditional wireless networks,
triggering the need for new communication protocols. In this context, the recently standardised IEEE
802.15.4 protocol presents some potentially interesting features for deployment in wireless sensor
network applications, such as power-efficiency, timeliness guarantees and scalability. Nevertheless,
when addressing WSN applications with (soft/hard) timing requirements some inherent paradoxes
emerge, such as power-efficiency versus timeliness, triggering the need of engineering solutions for an
efficient deployment of IEEE 802.15.4 in WSNs. In this technical report, we will explore the most
relevant characteristics of the IEEE 802.15.4 protocol for wireless sensor networks and present the
most important challenges regarding time-sensitive WSN applications. We also provide some timing
performance and analysis of the IEEE 802.15.4 that unveil some directions for resolving the
previously mentioned paradoxes
Frequency hopping in wireless sensor networks
Wireless sensor networks (WSNs) are nowadays being used to collectively gather and spread information in different kinds of applications, for military, civilian, environmental as well as commercial purposes. Therefore the proper functioning of WSNs under different kinds of environmental conditions, especially hostile environments, is a must and a lot of research currently ongoing. The problems related to the initialization and deployment of WSNs under harsh and resource limited conditions are investigated in this thesis.
Frequency hopping (FH) is a spread spectrum technique in which multiple channels are used, or hoped, for communications across the network. This mitigates the worst effects of interference with frequency agile communication systems rather than by brute force approaches. FH is a promising technique for achieving the coexistence of sensor networks with other currently existing wireless systems, and it is successful within the somewhat limited computational capabilities of the sensor nodes hardware radios.
In this thesis, a FH scheme for WSNs is implemented for a pair of nodes on an application layer. The merits and demerits of the scheme are studied for different kinds of WSN environments. The implementation has been done using a Sensinode NanoStack, a communication stack for internet protocol (IP) based wireless sensor networks and a Sensinode Devkit, for an IPv6 over low power wireless personal area network (6LoWPAN). The measurements are taken from the developed test bed and channel simulator for different kinds of scenarios. The detailed analysis of the FH scheme is done to determine its usefulness against interference from other wireless systems, especially wireless local area networks (WLANs), and the robustness of the scheme to combat fading or frequency selective fading
A Resource Intensive Traffic-Aware Scheme for Cluster-based Energy Conservation in Wireless Devices
Wireless traffic that is destined for a certain device in a network, can be
exploited in order to minimize the availability and delay trade-offs, and
mitigate the Energy consumption. The Energy Conservation (EC) mechanism can be
node-centric by considering the traversed nodal traffic in order to prolong the
network lifetime. This work describes a quantitative traffic-based approach
where a clustered Sleep-Proxy mechanism takes place in order to enable each
node to sleep according to the time duration of the active traffic that each
node expects and experiences. Sleep-proxies within the clusters are created
according to pairwise active-time comparison, where each node expects during
the active periods, a requested traffic. For resource availability and recovery
purposes, the caching mechanism takes place in case where the node for which
the traffic is destined is not available. The proposed scheme uses Role-based
nodes which are assigned to manipulate the traffic in a cluster, through the
time-oriented backward difference traffic evaluation scheme. Simulation study
is carried out for the proposed backward estimation scheme and the
effectiveness of the end-to-end EC mechanism taking into account a number of
metrics and measures for the effects while incrementing the sleep time duration
under the proposed framework. Comparative simulation results show that the
proposed scheme could be applied to infrastructure-less systems, providing
energy-efficient resource exchange with significant minimization in the power
consumption of each device.Comment: 6 pages, 8 figures, To appear in the proceedings of IEEE 14th
International Conference on High Performance Computing and Communications
(HPCC-2012) of the Third International Workshop on Wireless Networks and
Multimedia (WNM-2012), 25-27 June 2012, Liverpool, U
An eco-friendly hybrid urban computing network combining community-based wireless LAN access and wireless sensor networking
Computer-enhanced smart environments, distributed environmental monitoring, wireless communication, energy conservation and sustainable technologies, ubiquitous access to Internet-located data and services, user mobility and innovation as a tool for service differentiation are all significant contemporary research subjects and societal developments. This position paper presents the design of a hybrid municipal network infrastructure that, to a lesser or greater degree, incorporates aspects from each of these topics by integrating a community-based Wi-Fi access network with Wireless Sensor Network (WSN) functionality. The former component provides free wireless Internet connectivity by harvesting the Internet subscriptions of city inhabitants. To minimize session interruptions for mobile clients, this subsystem incorporates technology that achieves (near-)seamless handover between Wi-Fi access points. The WSN component on the other hand renders it feasible to sense physical properties and to realize the Internet of Things (IoT) paradigm. This in turn scaffolds the development of value-added end-user applications that are consumable through the community-powered access network. The WSN subsystem invests substantially in ecological considerations by means of a green distributed reasoning framework and sensor middleware that collaboratively aim to minimize the network's global energy consumption. Via the discussion of two illustrative applications that are currently being developed as part of a concrete smart city deployment, we offer a taste of the myriad of innovative digital services in an extensive spectrum of application domains that is unlocked by the proposed platform
Energy efficient wireless sensor network communications based on computational intelligent data fusion for environmental monitoring
The study presents a novel computational intelligence algorithm designed to optimise energy consumption in an
environmental monitoring process: specifically, water level measurements in flooded areas. This algorithm aims to obtain a tradeoff
between accuracy and power consumption. The implementation constitutes a data aggregation and fusion in itself. A harsh
environment can make the direct measurement of flood levels a difficult task. This study proposes a flood level estimation,
inferred through the measurement of other common environmental variables. The benefit of this algorithm is tested both with
simulations and real experiments conducted in Donñana, a national park in southern Spain where flood level measurements have
traditionally been done manually.Junta de Andalucía P07-TIC-0247
A software framework for alleviating the effects of MAC-aware jamming attacks in wireless access networks
The IEEE 802.11 protocol inherently provides the same long-term throughput to all the clients associated with a given access point (AP). In this paper, we first identify a clever, low-power jamming attack that can take advantage of this behavioral trait: the placement of a lowpower jammer in a way that it affects a single legitimate client can cause starvation to all the other clients. In other words, the total throughput provided by the corresponding AP is drastically degraded. To fight against this attack, we design FIJI, a cross-layer anti-jamming system that detects such intelligent jammers and mitigates their impact on network performance. FIJI looks for anomalies in the AP load distribution to efficiently perform jammer detection. It then makes decisions with regards to optimally shaping the traffic such that: (a) the clients that are not explicitly jammed are shielded from experiencing starvation and, (b) the jammed clients receive the maximum possible throughput under the given conditions. We implement FIJI in real hardware; we evaluate its efficacy through experiments on two wireless testbeds, under different traffic scenarios, network densities and jammer locations. We perform experiments both indoors and outdoors, and we consider both WLAN and mesh deployments. Our measurements suggest that FIJI detects such jammers in realtime and alleviates their impact by allocating the available bandwidth in a fair and efficient way. © Springer Science+Business Media
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