WRGP : Weight Aware Route Guiding Protocol for Wireless Sensor Networks with Obstacles

[[abstract]]The greedy forwarding routing protocol has been widely used for constructing a route with low control overheads in wireless sensor networks. However, its performance drops significantly when obstacles exist. This paper proposes a novel mechanism, named WRGP, which removes the impact of obstacles on the greedy forwarding routing. The proposed WRGP initially applies the previous research to specify the border nodes that surround the obstacle. Then the border nodes in the concave region of the obstacle initiate the weight assigning process and establish a forbidden region to prevent the packets from entering the concave region. Finally WRGP specifies some border nodes to act as the effective border nodes for constructing the optimal routes from themselves to the sink node. Comparing with the existing obstacles-resisting protocols, the proposed WRGP avoids the ping-pong effect and guides the packets moving along the shortest path from the encountered effective border node to the sink node. In addition, the M-WRGP is further developed to cope with the multi-obstacle problem. Simulation results show that both WRGP and M-WRGP outperform the existing protocol PAGER in terms of control overheads and average route length.[[notice]]本書目待補

LARP: a novel routing protocol for the Bluetooth scatternet

[[abstract]]In this paper we design an efficient location aware routing protocol (LARP) for the Bluetooth scartternet. Taking advantages of the location information of all nodes, LARP reconstructs the routing path dynamically and minimizes the number of hops between the source and the destination of the scatternet. Besides, the paper also presents a hybrid routing protocol (HLARP), which minimizes the routing path for the scatternet, taking location information of some nodes. Experimental results show that both of our protocols are efficient enough to construct the shortest routing paths over a multi-hop scatternet and bandwidth and power consumption are least as compared to other routing protocols that we have considered.[[conferencetype]]國際[[conferencedate]]20050306~20050308[[iscallforpapers]]Y[[conferencelocation]]Dubai, United Arab Emirate

Adaptive role switching protocols for improving scatternet performance in Bluetooth radio networks

[[abstract]]Bluetooth is a low-power, low-cost, and short-range wireless technology. A well structured scatternet, with the appropriate number of piconets and bridges for a specific traffic pattern, increases the performance of a Bluetooth network. However, the structure of a scatternet is difficult to control or predefine because the scatternet is formed using a distributed procedure, with the master and slaves of each piconet connected at random. The participation of mobile Bluetooth devices in a scatternet at different times also increases the difficulty of maintaining a good structure. A badly structured scatternet exhibits the following characteristics: too many bridges in the scatternet creates a guard slot overhead associated with bridge switching among the participating piconets, increasing the probability that a packet is lost; too many piconets in a communicative range causes packet collision and thus degrades the performance; unnecessary piconets also lengthen the routing path, delaying the transmission of packets from source to destination. The paper proposes a distributed scatternet reconstruction protocol for dynamically reorganizing the scatternet. Unnecessary bridges and piconets can be dynamically removed by applying a role switching operation, improving the packet error rate, saving guard slots, and reducing the average routing length. By experiment, it is shown that the proposed protocol improves the data transmission performance of a Bluetooth scatternet.[[conferencetype]]國際[[conferencedate]]20040905~20040908[[booktype]]紙本[[conferencelocation]]Barcelona, Spai

Path Guiding Mechanisms for Mobile Anchor Improving or Balancing Location Accuracies of Static Sensors in WSNs

[[abstract]]Location information is of utmost importance for most applications in wireless sensor networks. Recent localization schemes have been categorized into range and range-free based techniques. Obvious inclination is towards range free algorithms since they do not rely on special hardware that would be required in range based algorithms. In the most proposed range-free algorithms, nodes estimate their location using the geometric constraints imposed by the location of a mobile anchor. However, there is no discussion on how the mobile anchor moves so that the maximal location accuracies of all sensor nodes can be obtained with the constraint of energy consumption of a mobile anchor. This paper assumes that traditional range-free algorithms have been executed for a certain time period and the deployed sensors are with different location accuracies. We propose path guiding mechanisms that sensor nodes cooperatively guide the mobile anchor moving along an efficient path which can maximize the improvement of location accuracies or minimize the accuracy differences for all sensor nodes in a given WSN. Experimental study reveals that the proposed path guiding mechanisms effectively guide the mobile anchor moving along the efficient path and thereby saves time and energy consumptions for improving or balancing the location accuracies of all sensor nodes.[[conferencetype]]國際[[conferencedate]]20081014~20081017[[iscallforpapers]]Y[[conferencelocation]]Montreal, Que, Canad

[[alternative]]Design and Implementation of a High Performance Scatternet over Bluetooth Radio Systems (I)

計畫編號：NSC91-2213-E032-036研究期間：200208~200307研究經費：736,000[[sponsorship]]行政院國家科學委員

Design and implementation of ad hoc classroom and eSchoolbag systems for ubiquitous learning

[[abstract]]This paper describes the design and implementation of a learning technology project. The purpose of this project is to develop advanced wireless technologies for building an ad hoc classroom in order to contrive a modern and new learning environment. A wireless platform is developed for teacher and students to establish a classroom dynamically irrespective of location and time bounds. As supported in a traditional classroom, we develop information technology to provide the teacher with teaching aids, such as blackboard, board rubber, colored chalk, microphone, voice recorder, video recorder, and so on, for course teaching and discussions in an ad hoc classroom. In addition, we provide students with an electronic schoolbag (or eSchoolbag) which packs electronic book, notebook, parents contact book, pencil case, writing materials, sheets, calculator, address book, and so on. Taking lessons in a lively, vivid, and new learning environment, students are expected to enhance their learning performance without any burden like attending classes physically. Moreover students get more flexible scope of learning at a convenient time.[[conferencelocation]]Växjö, Swede

[[alternative]]Design and Implementation of Location-Based Communication Protocols for Multi-Tier Mobile Ad Hoc Networks (I)

計畫編號：NSC91-2219-E032-006研究期間：200208~200307研究經費：750,000[[sponsorship]]行政院國家科學委員

OFRD:Obstacle-Free Robot Deployment Algorithms for Wireless Sensor Networks

[[abstract]]Node deployment is an important issue in wireless sensor networks (WSNs). Sensor nodes should be efficiently deployed in a predetermined region in a low cost and high coverage quality manner. Random deployment is the simplest way for deploying sensor nodes but may cause the unbalanced deployment and therefore increase the hardware cost. This paper presents an efficient obstacle-free robot deployment algorithm, called OFRD which involves the design of node placement policy, snake-like movement policy, and obstacle handling rules. By applying the proposed OFRD, the robot rapidly deploys near-minimal number of sensor nodes to achieve full sensing coverage even though there exist unpredicted obstacles. Performance results reveal that OFRD outperforms the existing robot deployment mechanism in terms of power conservation and obstacle resistance, and, therefore achieves a better deployment performance.[[incitationindex]]Y[[conferencetype]]國際[[conferencedate]]20070311~20070315[[conferencelocation]]Kowloon, Hong Kon

On Providing Temporal Full-Coverage by Applying Energy-Efficient Hole-Movement Strategies for Mobile WSNs

[[abstract]]This paper considers a mobile WSN that contains a big hole but there exists no redundant mobile sensor to heal the hole. To achieve the temporal full-coverage purpose or enhance the tracking quality, three distributed algorithms are proposed for moving the existing big coverage hole to a predefined location. Firstly, the sink chooses a promising direction for hole-movement. Then the basic, forward-only and any-direction movement mechanisms are proposed to move the hole along the promising direction in a manner of minimizing the total power consumption or balancing the energy consumption of the given WSN. Simulation results reveal that the proposed hole-movement mechanisms enhance the coverage of WSN and balance the energy consumption of mobile sensor nodes.[[conferencetype]]國際[[conferencedate]]20070311~20070315[[iscallforpapers]]Y[[conferencelocation]]Kowloon, Hong Kon

Dynamic Route Sharing Protocol for Wireless Sensor Networks

[[abstract]]A wireless sensor networks (WSN) comprises of a large number of sensor nodes and a few sink nodes. When multiple sink nodes are interested in collecting the readings of the same monitoring region, itpsilas conducive to exploit the sharing route in order to save bandwidth and power consumption and prolong WSNpsilas lifetime. This paper proposes a dynamic route sharing protocol (DRSP) which constructs sharing routes based upon different attributes (for example, frequency, packet length or delay time) of the commands requested from different sink nodes. The proposed DRSP dynamically adjusts data transmission route to achieve the goals of routes sharing and route length reduction. Simulation study shows that DRSP saves more energy and bandwidth consumptions than the existing work and thus prolongs the WSNpsilas lifetime.[[conferencedate]]20080731~20080801[[iscallforpapers]]Y[[conferencelocation]]Lanzhou, Chin