PALM: A Partition Avoidance Lazy Movement Protocol for Mobile Sensor Networks

[[abstract]]The paper proposes a distributed partition avoidance lazy movement (PALM) protocol for mobile sensor networks (MSNs). In general, connectivity and coverage are two major factors to the success of a sensor network. Therefore, PALM takes both connectivity and coverage into account to avoid network partition and keep high sensing quality. Since sensor movement is the major source of energy consumption, thus, in order not to cause frequent movement, PALM triggers sensor movement only when the network has a risk of partition, but not when coverage holes appear. The paper proposes a sufficient condition of keeping a network connected. Based on the condition, PALM adopts the lazy movement policy for a sensor to determine when to move and uses the principles of an effective movement for a sensor to decide where to move. Accordingly, PALM can keep the network connected and can make the effective coverage as large as possible to maintain high sensing quality. In comparison with the related work, PALM can reduce the energy consumption and further extend the network lifetime due to the lazy movement policy and the principles of an effective movement. Simulation results also verify the advantages of the proposed protocol.[[conferencetype]]國際[[conferencedate]]20070311~20070315[[iscallforpapers]]Y[[conferencelocation]]Kowloon, Hong Kon

A Power Saving MAC Protocol by Increasing Spatial Reuse for IEEE 802.11 Ad Hoc WLANs

[[abstract]]Scarce resources of wireless medium (e.g., bandwidth, battery power, and so on) significantly restrict the progress of wireless local area networks (WLANs). Heavy traffic load and high station density are most likely to incur collisions, and further consume bandwidth and energy. In this paper, a distributed power-saving protocol, power-efficient MAC protocol (PEM), to avoid collisions and to save energy is proposed. PEM takes advantage of power control technique to reduce the interferences among transmission pairs and increase the spatial reuse of WLANs. Based on the concept of maximum independent set (MIS), a novel heuristic scheme with the aid of interference relationship is proposed to provide as many simultaneous transmission pairs as possible. In PEM, all stations know when to wake up and when they can enter doze state. Thus, stations need not waste power to idle listen and can save much power. The network bandwidth can be efficiently utilized as well. To verify the performance of PEM, a lot of simulations are performed. The experimental results show that with the property of spatial reuse, PEM not only reduces power consumption, but also leads to higher network throughput in comparison with the existing work, such as DCF, DCS, and DPSM.[[sponsorship]]IEEE Computer Society Technical Committee on Distributed Processing (TCDP); Tamkung University[[conferencetype]]國際[[conferencetkucampus]]淡水校園[[conferencedate]]20050328~20050330[[iscallforpapers]]Y[[conferencelocation]]臺北縣, 臺

An Intruder Avoidance Vulnerable Path Adjustment Protocol for Wireless Mobile Sensor Networks

[[abstract]]The paper proposes a protocol to adjust the vulnerable path by using mobile sensor networks. The objective of vulnerable adjustment is to protect some important areas, named TBP (to-be-protected) areas in the paper, from being attacked. In the paper, Voronoi diagram is utilized to And a vulnerable path, which is a path that an intruder may pass through. While the vulnerable path passes over a TBP area, a backward tracing and critical sets selection schemes are used to move the fewest number of sensors such that the vulnerable path can be changed and the new vulnerable path will not pass over the TBP area. Moreover, a moving schemes is proposed to decide where mobile sensors shall move. Since sensor movement is the major resource of energy consumption, thus, in order not to cause much movement, the proposed mechanism can move the fewest number of sensors with the shortest distance. Simulation results also verify the advantages of the proposed mechanism.[[sponsorship]]IEEE Taipei Section; National Science Council; Ministry of Education; Tamkang University; Asia University; Providence University; The University of Aizu; Lanzhou University[[conferencetype]]國際[[conferencetkucampus]]淡水校園[[iscallforpapers]]Y[[conferencelocation]]Tamsui, Taipei, Taiwa

A Fragmentation-Based Data Collision Free MAC Protocol with Power Control for Wireless Ad Hoc Networks

[[abstract]]Resolving hidden terminal problem is one of the major responsibilities in designing MAC protocols for wireless ad hoc networks. IEEE 802.11 DCF, currently the most popular used MAC protocol, adopts four-way handshake to prevent hidden terminal problem. However, it has been pointed out that four-way handshake cannot completely prevent hidden terminal problem because the STAs which are out of the transmission ranges of both the transmitter and the receiver may still interfere with the receiver. As a result, the paper proposes a fragmentationbased MAC protocol with power control, named F-RCRC MAC protocol, to avoid the LIRC (Large Interference Range Collision) problem, a kind of hidden terminal problem, for wireless ad hoc networks. F-RCRC designs a new interframe space, named FIFS, to reduce the overhead caused by the fragmentation scheme.With the fragmentation, the design of FIFS can effectively avoid the hidden STAs interfering with the receivers'receiving. Moreover, a dynamic transmission power scheme is devised to actively and timely warn the hidden STAs such that the possible collision is avoided. Thus, the LIRC problem can be solved and the network throughput is increased accordingly. In addition, F-RCRC can reduce the energy consumption and increase the spatial reuse due to the controlled transmission power. It is further shown that FRCRC can also solve the POINT problem and work correctly in multi-rate environments. Simulation results show that F-RCRC performs much better than the related work in terms of network throughput as well as the power throughput.[[sponsorship]]亞洲大學資訊學院[[conferencetype]]國內[[conferencedate]]20080331~20080331[[conferencedate]]20071220~20071221[[booktype]]紙本[[conferencelocation]]臺中, 臺

On QoS routing in TDMA-based mobile ad hoc networks

[[abstract]]With the popularity of multimedia, QoS service is demanding from day to day. The mobile ad hoc network is an important wireless network architecture, which is self-organized and without the assistance of basic infrastructures. QoS routing in mobile ad hoc networks is an important issue for wireless technology. The paper presents a distributed slots reservation protocol (DSRP) for QoS routing on TDMA-based mobile ad hoc networks. According to one-hop neighbor's information, some strategies to select the time slots in order to satisfy the QoS requirement and not to violate the hidden-terminal and exposed-terminal problems are proposed. Route maintenance and improvement are also provided to maintain or improve a route when the network topology is changed. According to the simulation results, the proposed protocol can not only increase the findings of a route with bandwidth requirement guaranteed but also raise the throughput and efficiency of the network.[[sponsorship]]I-Shou University;Technical Co-Sponsored by IEEE, Taipei Section; National Science Council;Ministry of Education; MTECH Corporation Ltd.;Winbond Electronics Corp.,etc.[[notice]]補正完畢[[conferencetype]]國際[[conferencedate]]20031214~20031216[[booktype]]紙本[[iscallforpapers]]Y[[conferencelocation]]高雄, 臺

A power control MAC protocol to increase spatial reuse for IEEE 802.11 Ad-Hoc wireless LANs

[[abstract]]The paper proposed a distributed spatial reuse MAC protocol (named DSR) for IEEE 802.11 ad-hoc wireless LANs to increase bandwidth utilization and reduce power con-sumption. Through power control, the sender uses the right power to send to the receiver. In this way, the transmission range and the power consumption can be decreased while the spatial reuse can be increased. The communications that do not interfere to each other are allowed to be done simultaneously. Therefore, the overall efficiency and effectiveness of IEEE 802.11 ad-hoc wireless LANs can be enhanced. DSR could allow the maximum number of interference-free communication pairs to transmit in parallel and prevent them from collisions. According to the experiment results, DSR is much better than traditional wireless LAN protocol, IEEE 802.11 DCF, and the related work. The protocol indeed could effectively enhance the overall wireless LANs efficiency.[[sponsorship]]長庚大學資訊工程學系；交通大學資訊工程學系; 國科會工程處工程科技推展中心；台灣聯合大學系統尖端資訊系統與電子研究中心(CAISER); 國科會後卓越計畫---後三代全IP無線網路技術；台灣微軟股份有限公司[[notice]]補正完畢[[conferencetype]]國內[[conferencedate]]20050331~20050331[[booktype]]紙本[[conferencelocation]]桃園縣, 臺

On Barrier Coverage in Wireless Camera Sensor Networks

[[abstract]]The paper proposed a distributed algorithm, namely CoBRA (Cone-based Barrier coveRage Algorithm), to achieve barrier coverage in wireless camera sensor networks (WCSNs). To the best understanding, CoBRA is the first algorithm which try to deal with the barrier coverage issue in WCSNs. Based on some observations, the basic concept of CoBRA is that each camera sensor can determine the local possible barrier lines according to the geographical relations with their neighbors. A sink in a WCSN initiates Barrier Request (BREQ) messages to form the possible barrier lines. Afterward, a barrier line is constructed by the Barrier Reply (BREQ) message initiated by another sink. CoBRA mainly includes three phases: Initial Phase, Candidate Selection Phase, and Decision Phase. In the Initial Phase, each camera sensor collects the local information of its neighbors and estimates the possible barrier lines. In the Candidate Selection Phase, a sink initiates the BREQ packets and forwards the BREQ packets to camera sensors. Camera sensors receiving the BREQ then reforward the BREQ packets to its neighbors who are capable of forming a barrier line. All camera sensors receiving the BREQ will forward the BREQ to their neighbors again in the same manner. Finally, in the decision phase, after the BREQ message is transmitted through the whole monitoring area, a BREP message is used by the sink to select a barrier line in a WCSN. The barrier coverage is achieved by finding the barrier line in the monitoring area. Experiment results show that CoBRA can efficiently achieve barrier coverage in WCSNs. Comparing to the ideal results, CoBRA can use fewer nodes to accomplish barrier coverage in random deployment scenarios.[[conferencetype]]國際[[conferencedate]]20100420~20100423[[iscallforpapers]]Y[[conferencelocation]]Perth, WA, Australi

Direction-based localization schemes for wireless sensor networks

[[abstract]]Localization is an important issue in wireless sensor networks (WSNs). Several applications in WSNs can tolerate the diverse levels of accuracy in geographic information such as physical location. Besides, direction information is sufficient for numerous applications in WSNs. Thus, the paper develops a direction-based localization scheme, DLS, in which a node can be aware of its relative direction to a sink rather than its physical absolute location without requiring additional equipments. DLS not only takes the spatial locality property into account, but also exploits the anchor deployment strategy to benefit sensor direction learning. Additionally, DLS can more precisely position sensors around the boundaries with the aid of the dual-direction coordinate system. Experimental results validate the practicability of DLS and show that DLS is able to achieve well accurate direction estimates.[[abstract]]Location awareness is an attractive research issue in the wireless sensor network (WSN). However, such information may be unavailable due to the constraints in energy, computation, or terrain, and several applications can tolerant the diverse level of accuracy in such geographic information. Thus, this paper presents a direction-based localization scheme, DLS, for each sensor node to determine its direction rather than its absolute location. DLS not only uses the anchor deployment strategy to benefit sensor direction learning, but also employs the dual-direction coordination system to precisely position the sensors close to the boundaries. We evaluate DLS via simulations in terms of various direction numbers, node numbers, and radio ranges. Experimental results validate the practicability of DLS, and show that DLS can effectively achieve direction estimation.[[sponsorship]]長庚大學資訊工程學系；交通大學資訊工程學系; 國科會工程處工程科技推展中心；台灣聯合大學系統尖端資訊系統與電子研究中心(CAISER); 國科會後卓越計畫---後三代全IP無線網路技術；台灣微軟股份有限公司[[notice]]補正完畢[[conferencetype]]國內[[conferencedate]]20050331~20050331[[booktype]]紙本[[iscallforpapers]]Y[[conferencelocation]]桃園縣, 臺

On Improving Network Connectivity by Power-Control and Code-Switching Schemes for Multihop Packet Radio Networks

[[abstract]]Packet radio network (PRN) consists of low or even no mobility stations each assigned with a code to prevent transmission from collision. A PRN with strong connectivity will help to reduce the route length and provide more alternatives for routing, improving the overall throughput and end-to-end delay. With power control mechanism, each station could be assigned with a power level to change the neighborhood relation and improve network connectivity. Assigning high transmitting power level to a station can enhance the network connectivity but may increase the number of neighbors, raising collision problem for parallel transmissions among neighbors. How to assign appropriate power level to improve the network connectivity with a constraint of limited codes is one of the most important issues in PRNs. Given a network topology and a set of codes that has been assigned to stations, the proposed power control and code switching mechanism assigns each station with a power level and a code to improve the network connectivity. Based on the matrix-based operation, the power control and code switching metrics in network connectivity problem are generally identified and efficiently resolved. Simulation study reveals that the proposed mechanism increases network throughput and provides a variety of route selection thus improves the performance of a given PRN.[[conferencetype]]國際[[conferencedate]]20050613~20050616[[iscallforpapers]]Y[[conferencelocation]]Hawaii, United State

CollECT: Collaborative Event deteCtion and Tracking in Wireless Heterogeneous Sensor Networks

[[abstract]]Event detection and tracking are attractive research issues in the wireless sensor network (WSN). The paper proposes a fully distributed protocol, CollECT, to event detection and tracking in a Wireless Heterogeneous Sensor Network (WHSN), composed of many kinds of sensors. In CollECT, three major procedures, vicinity triangulation, event determination, and border sensor selection are used to construct the logical triangle in the vicinity of a sensor, to determine the event, and to select the border sensor to identify the event boundary, respectively. The procedures perform repeatedly to both detect and track events. Simulation results demonstrate that CollECT is promising for event detection and tracking due to satisfactory event accuracy and reasonable fitness of border sensors.[[conferencetype]]國際[[conferencedate]]20060626~20060629[[iscallforpapers]]Y[[conferencelocation]]Sardinia, Ital