Wireless Mesh Network (WMN) is a new-type wireless network. Its core idea is that any of its wireless equipment can act as both an Access Point (AP) and a router. Each node in the network can send and receive signals ...Wireless Mesh Network (WMN) is a new-type wireless network. Its core idea is that any of its wireless equipment can act as both an Access Point (AP) and a router. Each node in the network can send and receive signals as well as directly communicate with one or several peer nodes. One important issue to be considered in wireless Mesh networks is how to secure reliable data transmission in multi-hop links. To solve the problem, the 3GPP system architecture proposes two functionalities: ARQ and HARQ. This paper presents two HARQ schemes, namely hop-by-hop and edge-to-edge, and three ARQ schemes: hop-by-hop, edge-to-edge, and last-hop. Moreover, it proposes three solutions for WMNs from the perspective of protocol stock design: layered cooperative mechanism, relay ARQ mechanism and multi-hop mechanism.展开更多
An improved self-organizing feature map (SOFM) neural network is presented to generate rectangular and hexagonal lattic with normal vector attached to each vertex. After the neural network was trained, the whole scatt...An improved self-organizing feature map (SOFM) neural network is presented to generate rectangular and hexagonal lattic with normal vector attached to each vertex. After the neural network was trained, the whole scattered data were divided into sub-regions where classified core were represented by the weight vectors of neurons at the output layer of neural network. The weight vectors of the neurons were used to approximate the dense 3-D scattered points, so the dense scattered points could be reduced to a reasonable scale, while the topological feature of the whole scattered points were remained.展开更多
Data dissemination is an important application in vehicular networks. We observe that messages in vehicular networks are usually subject to both time and space constraints, and therefore should be disseminated during ...Data dissemination is an important application in vehicular networks. We observe that messages in vehicular networks are usually subject to both time and space constraints, and therefore should be disseminated during a specified duration and within a specific coverage. Since vehicles are moving in and out of a region, dis-semination of a message should be repeated to achieve reliability. However, the reliable dissemination for some messages might be at the cost of unreliable or even no chance of dissemination for other messages, which raises tradeoffs between reliability and fairness. In this paper, we study the scheduling of data dis-semination in vehicular networks with mesh infrastructure. Firstly, we propose performance metrics for both reliability and fairness. Factors on both the time and space dimensions are incorporated in the reliability met-ric and the fairness in both network-wide and Mesh Roadside Unit-wise (MRU-wise) senses are considered in the fairness metric. Secondly, we propose several scheduling algorithms: one reliability-oriented algorithm, one fairness-oriented algorithm and three hybrid schemes. Finally, we perform extensive evaluation work to quantitatively analyze different scheduling algorithms. Our evaluation results show that 1) hybrid schemes outperform reliability-oriented and fairness-oriented algorithms in the sense of overall efficiency and 2) dif-ferent algorithms have quite different characteristics on reliability and fairness.展开更多
This work introduces a scalable and efficient topological structure for tetrahedral and hexahedral meshes. The design of the data structure aims at maximal flexibility and high performance. It provides a high scalabil...This work introduces a scalable and efficient topological structure for tetrahedral and hexahedral meshes. The design of the data structure aims at maximal flexibility and high performance. It provides a high scalability by using hierarchical representa-tions of topological elements. The proposed data structure is array-based, and it is a compact representation of the half-edge data structure for volume elements and half-face data structure for volumetric meshes. This guarantees constant access time to the neighbors of the topological elements. In addition, an open-source implementation named Open Volumetric Mesh （OVM） of the pro-posed data structure is written in C＋＋ using generic programming concepts.展开更多
文摘Wireless Mesh Network (WMN) is a new-type wireless network. Its core idea is that any of its wireless equipment can act as both an Access Point (AP) and a router. Each node in the network can send and receive signals as well as directly communicate with one or several peer nodes. One important issue to be considered in wireless Mesh networks is how to secure reliable data transmission in multi-hop links. To solve the problem, the 3GPP system architecture proposes two functionalities: ARQ and HARQ. This paper presents two HARQ schemes, namely hop-by-hop and edge-to-edge, and three ARQ schemes: hop-by-hop, edge-to-edge, and last-hop. Moreover, it proposes three solutions for WMNs from the perspective of protocol stock design: layered cooperative mechanism, relay ARQ mechanism and multi-hop mechanism.
基金Supported by Science Foundation of Zhejiang (No. 599008) ZUCC Science Research Foundation
文摘An improved self-organizing feature map (SOFM) neural network is presented to generate rectangular and hexagonal lattic with normal vector attached to each vertex. After the neural network was trained, the whole scattered data were divided into sub-regions where classified core were represented by the weight vectors of neurons at the output layer of neural network. The weight vectors of the neurons were used to approximate the dense 3-D scattered points, so the dense scattered points could be reduced to a reasonable scale, while the topological feature of the whole scattered points were remained.
文摘Data dissemination is an important application in vehicular networks. We observe that messages in vehicular networks are usually subject to both time and space constraints, and therefore should be disseminated during a specified duration and within a specific coverage. Since vehicles are moving in and out of a region, dis-semination of a message should be repeated to achieve reliability. However, the reliable dissemination for some messages might be at the cost of unreliable or even no chance of dissemination for other messages, which raises tradeoffs between reliability and fairness. In this paper, we study the scheduling of data dis-semination in vehicular networks with mesh infrastructure. Firstly, we propose performance metrics for both reliability and fairness. Factors on both the time and space dimensions are incorporated in the reliability met-ric and the fairness in both network-wide and Mesh Roadside Unit-wise (MRU-wise) senses are considered in the fairness metric. Secondly, we propose several scheduling algorithms: one reliability-oriented algorithm, one fairness-oriented algorithm and three hybrid schemes. Finally, we perform extensive evaluation work to quantitatively analyze different scheduling algorithms. Our evaluation results show that 1) hybrid schemes outperform reliability-oriented and fairness-oriented algorithms in the sense of overall efficiency and 2) dif-ferent algorithms have quite different characteristics on reliability and fairness.
基金Supported by Fundamental Research Funds for the Central Universities(Nos.2013ZM087,2012zz0062,2012zz0063)Doctoral Fund of Ministry of Education of China(No.20130172120010)
文摘This work introduces a scalable and efficient topological structure for tetrahedral and hexahedral meshes. The design of the data structure aims at maximal flexibility and high performance. It provides a high scalability by using hierarchical representa-tions of topological elements. The proposed data structure is array-based, and it is a compact representation of the half-edge data structure for volume elements and half-face data structure for volumetric meshes. This guarantees constant access time to the neighbors of the topological elements. In addition, an open-source implementation named Open Volumetric Mesh （OVM） of the pro-posed data structure is written in C＋＋ using generic programming concepts.
