Joint Energy-Balanced and Full-Coverage Mechanism Using Sensing Range Control for Maximizing Network Lifetime in WSNs

[[abstract]]Coverage is an important issue that has been widely discussed in wireless sensor networks (WSNs). However, it is still a big challenge to achieve both the purposes of full coverage and energy balancing. This paper considers the area coverage problem for a WSN where each sensor has variable sensing radius. A Weighted Voronoi Diagram (WVD) is proposed as a tool for determining the responsible sensing region of each sensor node according to the remaining energy in a distributed manner. To maximize the network lifetime, techniques for balancing energy consumptions of sensors are further presented. Performance evaluation reveals that the proposed joint energy-balanced and full-coverage mechanism, called EBFC, outperforms the existing studies in terms of network lifetime and degree of energy balancing.[[conferencetype]]國際[[conferencedate]]20120704~20120706[[booktype]]紙本[[booktype]]電子版[[iscallforpapers]]Y[[conferencelocation]]Phuket, Thailan

ORZBP: An Obstacle-Resistant Zone-based Broadcasting Protocol for Wireless Sensor Networks

[[abstract]]Wireless Sensor Networks (WSNs) comprise a few sink nodes and a large number of sensor nodes. The WSN environment contains unpredictable obstacles, such as mountains, lakes, buildings, or regions without any sensor node, impeding or blocking message relay. Broadcasting is an essential operation broadly used in WSNs. However, the blind flooding results in the large-scale waste of energy and bandwidth resources even though it is the simplest way to overcome obstacle-resistant problems. On the other hand, the blind flooding also raises the amount of packet collisions and contentions. This paper proposes a distributed obstacle resistant broadcasting protocol, called as ORZBP, to reduce the number of forwarding nodes and to overcome the obstacle problem. Experimental results reveal that ORZBP reduces the redundant bandwidth and power consumptions, avoids the possible packet collision as well as achieves the high success rate.[[conferencetype]]國際[[conferencedate]]20120625~20120627[[booktype]]紙本[[booktype]]電子版[[iscallforpapers]]Y[[conferencelocation]]Liverpool, U

Active Route-Guiding Protocols for Resisting Obstacles in Wireless Sensor Networks

[[abstract]]In wireless sensor networks, a geographic region without the functionality of sensing and communication can generally be treated as an obstacle, which significantly impacts the performance of existing location-based routing. An obstacle can dynamically be formed due to unbalanced deployment, sensor failure, or power exhaustion, animus interference, or physical obstacles such as mountains or buildings. This paper proposes novel algorithms that enable the existing location-based routing protocols that resist obstacles. Applying the proposed active route-guiding protocol for single obstacles (S-RGP), border nodes that surround the obstacles will actively establish a forbidden region for concave obstacles and make the obstacle information transparent. Then, packets will be guided to overcome the obstacle and move along the shorter path from the encountered border node to the sink node. In addition, the proposed active route-guiding protocol for multiple obstacles (M-RGP) takes multiple obstacles into consideration and integrates their information to help the packets overcome multiple obstacles. Simulation results show that the proposed S-RGP and M-RGP create low overhead and significantly reduce the average route length, and, therefore, improve the energy consumption and end-to-end delay for a wireless sensor network with obstacles.[[incitationindex]]SCI[[booktype]]紙

Tone-Based Localization for Distinguishing Relative Locations in Wireless Sensor Networks

[[abstract]]Bounding-box mechanism is a well-known low-cost localization approach for wireless sensor networks. However, the bounding-box location information cannot distinguish the relative locations of neighboring sensors, hence leading to a poor performance for some applications such as location-aware routing. This paper proposes a Differentiating Relative Locations (DRL) mechanism which uses a mobile anchor to broadcast tones and beacons aiming at distinguishing the relative locations of any two neighboring nodes. With the order of entering and leaving tone transmission range, each sensor is able to identify its relative location relation with each of its neighbors. In addition, two path planning mechanisms are proposed to guarantee that all sensors can identify their relative locations while the energy consumption of the mobile anchor can be effective. Theoretical analysis is developed to estimate the impacts of duty time of tone signals in terms of energy conservation and accuracy of relative locations. Experimental study reveals that the proposed mechanism effectively distinguishes relative locations of any two neighboring nodes and hence significantly improves the performance of location-aware routing in wireless sensor networks (WSNs).[[incitationindex]]SCI[[booktype]]紙

Adaptive route-sharing protocol for data collection in Wireless Sensor Networks

[[abstract]]A Wireless Sensor Network (WSN) comprises 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, it is conducive to exploit the sharing route to save bandwidth and power consumption and prolong WSNs lifetime. This paper proposes a Dynamic Route-Sharing Protocol (DRSP), which constructs sharing routes based on 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. The simulation study shows that DRSP saves more energy and bandwidth consumptions than the existing work and thus prolongs the WSNs lifetime.[[journaltype]]國外[[incitationindex]]SCI[[booktype]]紙本[[countrycodes]]GB

Energy-Aware Node Placement, Topology Control and MAC Scheduling for Wireless Sensor Networks

[[abstract]]In the WSNs, the nodes closer to the sink node have heavier traffic load for packet forwarding because they do not only collect data within their sensing range but also relay data for nodes further away. The unbalanced power consumption among sensor nodes may cause network partition. This paper proposes efficient node placement, topology control, and MAC scheduling protocols to prolong the sensor network lifetime, balance the power consumption of sensor nodes, and avoid collision. Firstly, a virtual tree topology is constructed based on Grid-based WSNs. Then two node-placement techniques, namely Distance-based and Density-based deployment schemes, are proposed to balance the power consumption of sensor nodes. Finally, a collision-free MAC scheduling protocol is proposed to prevent the packet transmissions from collision. In addition, extension of the proposed protocols are made from a Grid-based WSN to a randomly deployed WSN, enabling the developed energy-balanced schemes to be generally applied to randomly deployed WSNs. Simulation results reveal that the developed protocols can efficiently balance each sensor node’s power consumption and prolong the network lifetime in both Grid-based and randomly deployed WSNs.[[incitationindex]]SC

A Novel Multi-Channel MAC Protocol with Directional Antenna for Enhancing Spatial Reuse and Bandwidth Utilization in WLANs

[[abstract]]This paper aims at developing an efficient MAC protocol for wireless LAN by considering multi-channel and directional antennae. Extending IEEE 802.11 to a multi-channel environment not only exploits the bandwidth utilization but also reduces the degree of contentions. Involving directional antennae in designing multi-channel MAC protocol additionally increases the spatial reuse, allowing more parallel communications. This study proposes an efficient Multi-Channel MAC protocol with a Directional Antenna (MCDA) for WLAN. Since each station is only equipped with a single antenna, communicating pairs that progress their communications on data channels cannot maintain the channel usage information which is only obtained from the control channel, raising the channel collision problem. The proposed protocol adopts the channel switch sequence (CSS) mechanism to cope with the channel collision problem and to reduce message exchange overhead for switching channels. According to the state management, MCDA then controls directional antenna transmitting data on a selected channel to exploit the opportunities of spatial reuse, and to maintain fairness among communicating pairs. Simulation results show that the proposed MCDA protocol maintains the fairness and significantly improves bandwidth utilization and throughput.[[incitationindex]]SCI[[incitationindex]]EI[[booktype]]紙

Hierarchical Cellular-Based management for mobile hosts in Ad-Hoc wireless networks

[[abstract]]This study proposes a hierarchical Cellular-Based management model for Mobile Ad-Hoc Networks. The proposed management model allows the mobile host to establish a stable communication path with fewer flooding messages and smaller hop count. In the single-level management, a host is selected to act as manager, constructing a communication path and managing the mobile hosts in a specific cellular region to significantly reduce the number of flooding packets. Two-level management is also proposed, to reduce the hop count and enhance the efficiency of constructing the QoS routing path. The Cellular-Based management model is compared with Triangular- and Zone-based management models. Performance evaluation shows that hierarchical Cellular-Based management more efficiently reduces the number of flooding messages and the hop count of the routing paths.[[incitationindex]]SC

Accident Aware Localization Mechanism for Wireless Sensor Networks

[[abstract]]Accurate location information is important for event reporting, coverage estimation, and location-aware routing in a Wireless Sensor Network (WSN). Recently, a number of range-free localization schemes have been proposed to provide each static sensor with location information, which is represented by a rectangular region. However, most WSN applications are applied in outdoor environments where the sensors’ location regions could be incorrect due to sudden accidents. This paper proposes an Active Location Correction Protocol, called ALCP, for detecting and correcting the occurrence of location error based on the bounding box technology. Performance study reveals that applying the ALCP to improve the location accuracies can enhance the performance of the well-known GPSR routing in terms of routing length, sensing coverage, and packet arrival rate.[[incitationindex]]SCI[[booktype]]電子

Throughput-Enhanced Relay Placement Mechanism in WiMAX 802.16j Multihop Relay Networks

[[abstract]]The IEEE 802.16j standard proposes a multihop relay network architecture that introduces relay stations aiming at increasing the network throughput or coverage. The deployment of the relay stations is one of the most important issues that determine the network throughput. In literature, some deployment strategies have been proposed. However, none of them follows the frame structure designed in IEEE 802.16j standard. Furthermore, they did not consider the fact that the bandwidth constraints of a base station, relay stations, and mobile stations (MSs) are highly related to the locations of relays. Given a base station, $k$ relay stations, and a region that can be fully covered by the base station, this paper proposes a relay deployment mechanism aiming to determine the best deployed locations for relays so that the bandwidth requirement of MSs can be satisfied while the network throughput can be significantly improved. Performance study reveals that the proposed relay deployment mechanism can improve the network throughput as compared with the existing approaches.[[notice]]補正完畢[[journaltype]]國外[[incitationindex]]SCI[[ispeerreviewed]]Y[[booktype]]電子版[[countrycodes]]US