The Experts below are selected from a list of 7176 Experts worldwide ranked by ideXlab platform
Yikchung Wu - One of the best experts on this subject based on the ideXlab platform.
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a distributed multihop time synchronization protocol for wireless sensor networks using pairwise broadcast synchronization
IEEE Transactions on Wireless Communications, 2009Co-Authors: K Y Cheng, Yikchung WuAbstract:Recently, a time synchronization algorithm called pairwise broadcast synchronization (PBS) is proposed. With PBS, a sensor can be synchronized by overhearing synchronization Packet Exchange among its neighbouring sensors without sending out any Packet itself. In an one-hop sensor network where every node is a neighbour of each other, a single PBS message Exchange between two nodes would facilitate all nodes to synchronize. However, in a multi-hop sensor network, PBS message Exchanges in several node pairs are needed in order to achieve network-wide synchronization. To reduce the number of message Exchanges, these node pairs should be carefully chosen. In this paper, we investigate how to choose these ldquoappropriaterdquo sensors aiming at reducing the number of PBS message Exchanges while allowing every node to synchronize. This selection problem is shown to be NP-complete, for which the greedy heuristic is a good polynomial-time approximation algorithm. Nevertheless, a centralized algorithm is not suitable for wireless sensor networks. Therefore, we develop a distributed heuristic algorithm allowing a sensor to determine how to synchronize itself based on its neighbourhood information only. The protocol is tested through extensive simulations. The simulation results reveal that the proposed protocol gives consistent performance under different conditions with its performance comparable to that of the centralized algorithm.
K Y Cheng - One of the best experts on this subject based on the ideXlab platform.
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a distributed multihop time synchronization protocol for wireless sensor networks using pairwise broadcast synchronization
IEEE Transactions on Wireless Communications, 2009Co-Authors: K Y Cheng, Yikchung WuAbstract:Recently, a time synchronization algorithm called pairwise broadcast synchronization (PBS) is proposed. With PBS, a sensor can be synchronized by overhearing synchronization Packet Exchange among its neighbouring sensors without sending out any Packet itself. In an one-hop sensor network where every node is a neighbour of each other, a single PBS message Exchange between two nodes would facilitate all nodes to synchronize. However, in a multi-hop sensor network, PBS message Exchanges in several node pairs are needed in order to achieve network-wide synchronization. To reduce the number of message Exchanges, these node pairs should be carefully chosen. In this paper, we investigate how to choose these ldquoappropriaterdquo sensors aiming at reducing the number of PBS message Exchanges while allowing every node to synchronize. This selection problem is shown to be NP-complete, for which the greedy heuristic is a good polynomial-time approximation algorithm. Nevertheless, a centralized algorithm is not suitable for wireless sensor networks. Therefore, we develop a distributed heuristic algorithm allowing a sensor to determine how to synchronize itself based on its neighbourhood information only. The protocol is tested through extensive simulations. The simulation results reveal that the proposed protocol gives consistent performance under different conditions with its performance comparable to that of the centralized algorithm.
M. Ohta - One of the best experts on this subject based on the ideXlab platform.
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MIS Protocol for Secure Connection and Fast Handover on Wireless LAN
20th International Conference on Advanced Information Networking and Applications - Volume 1 (AINA'06), 2006Co-Authors: H. Morioka, H. Mano, M. Ohrnori, M. OhtaAbstract:MIS (mobile Internet services) architecture is designed for secure connection and fast handover with wireless LAN. This architecture consists of three protocols, MISP (mobile Internet services protocol), MISAUTHP (mobile Internet services authentication protocol) and MIS MobilelP, and two kinds of servers, authentication servers and home agent, base routers and mobile nodes. MISP is a protocol designed for authentication, IP address assignments, session key Exchanges and various negotiations between mobile nodes and base routers with one-round-trip Packet Exchange after a mobile node receives beacons. MISP quickly establishes link between mobile nodes and base routers. MISAUTHP is a protocol for authentication between authentication servers and base routers. MISAUTHP can authenticate mobile nodes and base routers with single Exchange of Packets too, MIS MobilelP is a mobility support protocol for IPv4. This is a subset of RFC2002 MobileIP. We mainly describe about MISP, MISAUTHP and comparison between MISP with MISAUTHP and IEEE802.11 with IEEE802.1x
Mohsen Guizani - One of the best experts on this subject based on the ideXlab platform.
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v2v routing in a vanet based on the autoregressive integrated moving average model
IEEE Transactions on Vehicular Technology, 2019Co-Authors: Liangjun Song, Hongfang Yu, Victor Chang, Xiaojiang Du, Mohsen GuizaniAbstract:With the development of vehicle networks, the information transmission between vehicles is becoming increasingly important. Many applications, particularly regarding security, are based on communication between vehicles. These applications have strict requirements for factors such as the quality of communication between vehicles and the time delay. Many theoretical communication protocols ignore the presence of buildings or other obstacles that are present during practical use, especially in urban areas. These obstacles can cause a signal to fade or even block direct communication. Many vehicles are often parked at the roadside. Because of their location, these parked vehicles can be used as relays to effectively reduce the shadowing effect caused by obstacles and even solve communication problems. In this paper, we study the problem of parked-vehicle-assistant relay routing communication in vehicle ad hoc networks. We propose an efficient parked vehicle assistant relay routing algorithm that is composed of four parts: a periodic Hello Packet Exchange mechanism, candidate relay list update, communication link quality evaluation, and candidate relay list selection. Simulation results reveal obvious advantages for indexes such as the quality of communication, success rate, and time delay.
Robert C Durst - One of the best experts on this subject based on the ideXlab platform.
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orchestrating spatial reuse in wireless ad hoc networks using synchronous collision resolution scr
Journal of Interconnection Networks, 2002Co-Authors: J A Stine, Gustavo De Veciana, Kevin H Grace, Robert C DurstAbstract:We propose a novel medium access control protocol for ad hoc wireless networks data to send can contend simultaneously for the channel. Nodes contend for access using a synchronous signaling mechanism that achieves two objectives: it arbitrates contentions locally and it selects a subset of nodes across the network that attempt to transmit simultaneously. The subset of nodes that survive the signaling mechanism can be viewed as an orchestrated set of transmissions that are spatially reusing the channel shared by the nodes. Thus the 'quality' of the subset of nodes selected by the signaling mechanism is a key factor in determining the spatial capacity of the system. In this paper, we propose a general model for such synchronous signaling mechanisms and recommend a preferred design. We then focus via both analysis and simulation on the spatial and capacity characteristics of these access control mechanisms. Our work is unique in that it specifically focuses on the spatial capacity aspects of a MAC protocol, as would be critical for ad hoc networking, and shows SCR is a promising solution. Specifically, it does not suffer from congestion collapse as the density of contending nodes grows, it does not suffer from hidden or exposed node effects, it achieves high capacities with a spatial usage exceeding 1 (i.e. more than one Packet Exchange in the area covered by a transmission), and it facilitates the integration of new physical layer capacity increasing technologies.
