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
In this paper, the challenges with and motivations for developing millimeter wave and terahertz communications are described. A high-bye candidate architecture is presented, and use cases highlighting the potential ap...In this paper, the challenges with and motivations for developing millimeter wave and terahertz communications are described. A high-bye candidate architecture is presented, and use cases highlighting the potential applicability of high-frequency links are discussed. Mobility challenges at these higher frequencies are also discussed. Difficulties that arise as a result of high carrier frequencies and higher path loss can be overcome by practical, higher-gain antennas that have the added benefit of reducing intercell interference. Simulation methodology and results are given. The results show that millimeter wave coverage is possible in large, outdoor spaces, and only a reasonable number of base stations are needed. Network throughput can exceed 25 Gbit/s, and cell-edge user throuqhput can reach aDoroximatelv 100 Mbit/s.展开更多
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.
文摘In this paper, the challenges with and motivations for developing millimeter wave and terahertz communications are described. A high-bye candidate architecture is presented, and use cases highlighting the potential applicability of high-frequency links are discussed. Mobility challenges at these higher frequencies are also discussed. Difficulties that arise as a result of high carrier frequencies and higher path loss can be overcome by practical, higher-gain antennas that have the added benefit of reducing intercell interference. Simulation methodology and results are given. The results show that millimeter wave coverage is possible in large, outdoor spaces, and only a reasonable number of base stations are needed. Network throughput can exceed 25 Gbit/s, and cell-edge user throuqhput can reach aDoroximatelv 100 Mbit/s.
