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In this paper, we propose a modification of the observe extension of CoAP to include Quality of Service (QoS) support for timeliness. The proposed QoS support is based on delivery priority. Nodes are able to express the priority order with which they wish to be notified. Furthermore, they are also able to specify which notification they want to receive. We classify the notifications in two categories:...
Based on the requirement of the transmission of real-time service in wireless sensor networks, the paper studies Weighted Fair Queuing (WFQ) algorithm profoundly. Having analyzed the reason why WFQ can't ensure the quality of real-time service, it proposes P-WFQ, which is a priority-based Weighted Fair Queuing (P-WFQ) algorithm. With sliding windows, P-WFQ combines WFQ and the priority-based mechanism...
In the recent decade, datacenters have emerged to play an increasingly important role in cloud-based computing systems. It is shown that wireless sensor networks (sensornets) can provide fine-grained measurement and flexible coverage for the datacenter platform, and help achieve better control and energy efficiency [1]-[3]. In these applications, sensor nodes are only passive information receivers,...
With advances in low-power and low-cost wireless and sensor technologies, using WSNs in eHealthCare system has yielded tremendous efforts in recent years. However, most of previous researches adopt a remote server to process large scale of health sensor data forwarded by gateways that allow for interconnecting WSNs to IP network. In this paper, we present a prototype of a smart 6LoWPAN border router...
Today's access networks are increasingly shaped by the services that they provide to the end users. In a hybrid wireless-optical broadband access network (WOBAN), to access any service, the corresponding requests for the services and responses require multi-hop communication over the wireless mesh network (WMN) and Passive Optical Network (PON) subsequently over the Internet to some server in the...
Industrial wireless sensor network have emerged as an interesting and important research area in the last few years. Time synchronization is required for consistent distributed sensing and industrial control. In order to realize united time, the united time service system or the time server must be established. Based on industrial wireless sensor networks, information fusion automatically analyzes...
This paper presents an indoor positioning system called LOSNUS (LOcalization of Sensor Nodes by Ultra-Sound). It offers high accuracy of ~10 mm, a locating rate up to ~10 cycles/s and is applicable for both tracking mobile and locating static devices. LOSNUS is mainly designed to localize static devices especially in a wireless sensor network (WSN) with numerously deployed sensor/actuator devices...
Geographic routing has proven to be an efficient and scalable routing protocol for wireless sensor networks due to exploiting pure location information of sensor nodes for routing data packets. To enable geographic routing, source nodes must be aware of the location of the sinks, which is typically achieved by a location service. In this paper, we propose an on-demand location service (OLS) for geographic...
Time synchronization plays a key role in the wireless sensor networks (WSN).High precise time synchronization is all application foundation in distributed control systems. In order to realize united time, the united time service system or the time server must be established. Based on wireless sensor networks, information fusion automatically analyzes and monitors information under the certain criterion,...
The objective of Synchronization In wireless sensor network is to synchronize the various sensor nodes which are distributed as well as moving in a network. Synchronization is an important problem in communication networks especially for real time applications. There may be one base station of 1000 sensor nodes moving in the network. Synchronization is considered a particularly difficult in wireless...
In this study, we propose intersection collision avoidance system in preventing traffic crashes at typical urban intersections. The proposed intersection crash prevention system would display the crash warning messages to the drivers when crash-prone conditions are detected through the sensor system installed along intersection approaches. It would further change the traffic signal setting in real-time,...
The deployment of wireless technologies for public transport may imply several constraints due to specific environment, such as tunnels. In this paper, we evaluate the performance of IEEE 802.11a based networks deployed for infrastructure-to-train communications in underground tunnels. The signal attenuation specific to the tunnel propagation is taken into account. We propose an optimization of the...
Performance of transport control protocol (TCP) in wireless mesh networks (WMNs) has been a topic of intense research interest. The interest is aimed to provide high-speed TCP connectivity on the wireless mesh backbone that acts as an extension to the wired infrastructure of the Internet. As an effort to actualize this aim, we propose a framework incorporating orthogonal radio channels and novel mechanisms...
The purpose of this project is to integrate the technologies of wireless sensor networks and public communication networks to construct a healthcare system for senior citizens at home without interfering their daily activities. This system provides 4 main functionalities, including indoor monitoring, outdoor monitoring, activity and health state decision, emergency decision and alarm. JTH has developed...
IP-based Wireless Sensor Networks (IP-WSN) are envisioned to play an important role in the realization of pervasive environments. Comprised of hundreds or even thousands of nodes, these networks may never undergo pre-deployment address configuration. The stateless autoconfiguration capability is therefore essential to the spontaneity of such pervasive networks. Recently, several address autoconfiguration...
This paper presents an Agent-based Timing-Sync Algorithm (ATSA) for sensor networks that aims at providing network-wide time synchronization in a sensor network. ATSA works in three steps as following. Firstly, the root time node is selected, and then a hierarchical structure is established in the network, finally, by using time-agent, a pair wise synchronization is performed along the edges of this...
The main goal of wireless sensor networks is to gather information from the region of interest through a large number of micro sensor nodes. This gathering is based on a communication architecture such as client/server which consumes a lot of power and doesn't take in consideration the information properties. In this paper, we propose a new communication architecture for wireless sensor networks based...
Many protocols designed for wireless sensor networks require the existence of special purpose nodes distributed throughout the network to perform such services as aggregation, access coordination, etc. To avoid inter-node interference, it is desirable to schedule beforehand the nodes that will interact with the servers in a given time interval. Previous solutions either assume a fully connected network...
Video multicast handoff in wireless networks is challenged by various impairments, such as high bit-error-rate, connection disruption and asynchronous stream concatenation. We tackle this problem by proposing a two-stage multicast approach, where a video stream is distributed to a group of access routers using a regular IP multicast. Within a local subnet, each access router further replicates and...
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