首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 0 毫秒
1.
1IntroductionAs the development of MEMStechnology,the microsensors whichintegrate manyfunctions such as sensing,signal processing and communication have been widelyused[1]. Wireless Sensor Network ( WSN) is construct-ed with hundreds to thousands of sensors and one ormore SINKs .Sensors can sense (monitor) many physi-cal signals such as sound,light ,electronics ,tempera-ture and humidity of the objects in a given region[2 ~3].Sensors transfer these signalsinto sensing data and sendsensin…  相似文献   

2.
In wireless sensor networks (WSNs), the performance and lifetime are significantly affected by the indoor propagation and the interference from other technologies using the 2.4 GHz band. Next to an overview of the propagation and coexistence issues in the literature, we present a model for analysing these effects in WSNs. We also present our measurements results on the indoor propagation, the interference of the microwave oven (MWO) and their impact on the performance of the WSN. The propagation measurements reveal significant influence of the multipath: changing a node position with a few centimetres or changing the communication channel can lead up to 30 dB difference in the received power. The power leakage of MWO has been observed around $-$ 20 dBm at 1 m distances to the oven. This leads to extra retries of the 802.15.4 messages which matches our simulation results: the packet success ratio at first try decreases to 30–40 %, which increases the average active time of the sensor, closely located to the MWO. We observe that the ON–OFF pattern of the MWO could be exploited by WSNs to improve the performance.  相似文献   

3.
A Tracking-Based Target Locating Algorithm in Wireless Sensor Networks   总被引:5,自引:0,他引:5  
1 IntroductionAwirelesssensornetworkisusuallycomposedofhundredsorthousandsofsensorsequippedwithcomputation ,sensingandcommunicationdevices,whicharecoordinatedinadistributedmodeinordertomonitoracertaingeographicalregionandcollectinformationontheirsurroundings[1 ] .Thecollecteddataisthenusedtoanswervariousqueries.RecentadvancesinMEMS ,wirelesscommunications,anddigitalelectronicshavemadepossiblethecheapandfastdeploymentofsensornetworks[2 ] .Suchadhoc,self organizingsensornetworksarereceivingin…  相似文献   

4.
Wireless Personal Communications - Wireless sensor networks have been considered as an emerging technology for numerous applications of cyber-physical systems. These applications often require the...  相似文献   

5.
1IntroductionAdvances in the miniaturization of MicroElectronicand Mechanical Structures(MEMS)haveledto batterypowered sensor nodes that have sensing,communica-tion,and processing capabilities[1~4].Sensor networkshave emerged as an indispensable and i mpo…  相似文献   

6.
In large-scale Wireless sensor networks (WSNs), the network status is complex and unpredictable, which brings great challenges to practical network design and management. Tracing the route path of each data packet in the network is an important way to observe network behaviors and understand network dynamics. However, tracing the full route path of each packet could be highly challenging, due to the hard resource con- straint in WSNs. Our previous work proposes a hash-based path tracing mechanism, and leverages network connectivity and node locations to reduce the computational complexity. However, the node locations may be unavailable in some scenarios. In this work, we further propose a location-free enhancement to the hash-based path tracing mechanism, called P-Zone. P-Zone requires only network connectivity information to reduce the computational complexity. Theoretical analysis and practical simulations are conducted to evaluate the effectiveness and performance of our design. The results indicate that P-Zone can significantly reduce the computational complexity of the hashbased path tracing mechanism, while effectively tracing the full route path of each packet in the network in a real-time manner, and outperforms the state-of-the-art methods.  相似文献   

7.
1 Introduction TransmissionControlProtocol (TCP)isthedefactotransportprotocolfortheglobalInternet.TCPusesbasicIPservicestoprovideapplicationswithanend to endconnection oriented packettransportmechanism ,whichensuresthereliableandordereddeliveryofdata .ButconventionalTCPschemesmaysufferfromaseveredegradationinperformanceinwirelessenvironmentbecauseofcertaincharacteris ticsofwirelessnetworks ,suchasnon congestionlosses[1 ] ,longdelays[2 ] ,anddynamicchangingtopology[3] . ManyTCPperform…  相似文献   

8.
9.
10.
1Introduction Wirelesscommunicationhasbeenahotissuesince1990.includingAdhocandwirelesssensornetworks,etc.Especially,WirelessSensorNetwork(WSN).Whichhasreceivedconsiderableattentionduringlast decade[1-2].Ithasbeendevelopedforawidevarietyof applications,inc…  相似文献   

11.
In this paper, we utilize clustering to achieve energy efficiency for the on–off wireless sensor network, whose member nodes alternate between active and inactive states. In the proposed Distributed and Energy Efficient Self Organization (DEESO) scheme, the head election is adjusted adaptively to the remaining battery levels of local active nodes, which is a completely distributed approach compared to LEACH that relying on other routing schemes to access global information. Furthermore, we apply the Adaptive Channel Assignment (ACA) to address the on-off topology changes. Simulation results show that DEESO delivers 184% amount of data to the base station as LEACH for the same amount of energy consumption and the effective network lifetime is extended by around 50%.  相似文献   

12.
Wireless sensor networks have attracted significant interest for various scientific, military, and e-health applications. Recently a new class of sensor networks ??sensor/actor networks?? has been introducing new research challenges due to the unique coordination requirements among sensors and actors. In sensor/actor networks, actors are the nodes that have the capability to move in the field, equipped with powerful devices and can respond to the events of interest. With this capability, autonomous operation of the network is possible without a centralized controlling mechanism. This, however, requires the network to apply cooperative mechanism to decide when and how monitoring is done to track the event and how the event will be responded. In this regard, little work has been done in terms of co-existing Push and Pull data flows in the network. In this paper, we propose an Adaptive Pull?CPush (APP) based Event Tracking approach that allows sensor-to-actor communication as well as actors coordination in response to the events occurred. APP proposes two models of sensors organization: region-based organization (RAPP) and neighbor-based organization (NAPP) to alert nodes in the vicinity of reported event. APP exploits the mobility of actor nodes to form dynamic responsibility clusters, thus ensuring an event specific response to emergencies. Routing in APP is based on Routing by Adaptive Targeting (RAT), which is a delay-constrained geographical routing protocol. Simulation results reveal significant performance improvement in terms of response time and energy conservation.  相似文献   

13.
1IntroductionA wireless sensor network is the combination of thephysical world and information technology.Sensor net-works can contain hundreds of thousands of cheap sens-ing nodes that work in the formof Ad Hoc networks,monitoring the environment andrepo…  相似文献   

14.
Wireless Personal Communications - Recent rich applications for the Internet of Things are demanding large bandwidth for communication which can cause congestion within multi-hop wireless sensor...  相似文献   

15.
operation system (OS), named TaraxOS for wireless sensor networks is proposed. The functions of the TaraxOS such as interrupt, memory management and scheduling mechanism are researched and implemented. After introducing the node's working flow, the performances of the TaraxOS are analyzed and some limitations of the scheduling mechanism are discussed. The obtained results show that the proposed TaraxOS has some desirable characteristics including small code capacity, low power consumption, quick response and robustness.  相似文献   

16.
Wireless sensor nodes span a wide range of applications. This paper focuses on the biomedical area, more specifically on healthcare monitoring applications. Power dissipation is the dominant design constraint in this domain. This paper shows the different steps to develop a digital signal processing architecture for a single channel electrocardiogram application, which is used as an application example. The target power consumption is 100 μW as that is the power energy scavengers can deliver. We follow a bottleneck-driven approach: first the algorithm is tuned to the target processor, then coarse grained clock-gating is applied, next the static as well as the dynamic dissipation of the digital processor is reduced by tuning the core to the target domain. The impact of each step is quantified. A solution of 11 μW is possible for both radio and DSP running the electrocardiogram algorithm.
Jef Van MeerbergenEmail:
  相似文献   

17.

Wireless Sensor Network (WSN) consists of randomly distributed sensor nodes which can collect, process, route and transmit data from their respective environment. Most of the research on WSN is oriented towards optimizing utilization of finite resources of Sensor Nodes to increase the overall network operative time. Recent literature on WSNs reveals that hierarchical routing unequal clustering methodologies are gaining popularity due to energy efficiency, load balancing and scalability. In literature, numerous surveys on clustering methodologies are available which address different equal clustering methods. The unequal clustering protocols, which have their own attributes viz. balance load distribution, hot spot mitigation and energy efficiency, are comparatively less explored. This motivated us to undertake the present study on the taxonomy, comparison and simulation analysis of different methodologies pertaining to less explored unequal clustering protocols. Our base metrics for comparison of different unequal clustering protocols are scalability, energy efficiency & load balancing capability of the resulting network. A comprehensive discussion has also been presented to highlight the various advantages and disadvantages of different unequal clustering protocols. Further, we have summarized the study of unequal clustering protocols in the tabular form.

  相似文献   

18.
19.
The Wireless Sensor Network (WSN) is a distributed Ad-hoc network that consists of numerous and ubiquitous mini sensor nodes with the capabilities of wireless communicating and computing. The WSN is an "intelligent" system that enables self-fulfillment of…  相似文献   

20.
Considering the features of non-uniformlydistributed traffc load and possibly existing of the traffics requiring different performance in wireless sensor networks, this paper proposes EAQR, a novel routing protocol based on an improved Ant colony optimization (ACO)algorithm. The algorithm concentrates on the provisionof QoS and balanced energy-consumption over the wholenetwork. With the introduction of some metrics like theminimum path energy and path hop count and by means ofadvancing pheromone trail model of the ant colony system,the algorithm innovatively provides two heuristic ways respectively based on the length and the comfort of path tomeet the different performance requirements of real timeand common traffcs. Simulation experiments show thatEAQR has the following advantages comparing with existing algorithm: (1) differentiates dissemination service forReal time (RT) and Best effort (BE) traffc; (2) achieveslower delay for RT traffc; (3) exhibits substantially longernetwork lifetime; (4) behaves more scalable and robust.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号