In 3G networks upgraded with high speed packet access(HSPA) technology,the high access bandwidth and advanced mobile devices make it applicable to share large files among mobile users by peer-to-peer applications.To r...In 3G networks upgraded with high speed packet access(HSPA) technology,the high access bandwidth and advanced mobile devices make it applicable to share large files among mobile users by peer-to-peer applications.To receive files as quickly as possible is essential for mobile users in file sharing applications,since they are subject to unstable signal strength and battery failures.While many researches present peer-to-peer file sharing architectures in mobile environments,few works focus on decreasing the time spent in disseminating files among users.In this paper,we present an efficient peer-to-peer file sharing design for HSPA networks called efficient file sharing(EFS) for 3G networks.EFS can decrease the dissemination time by efficiently utilizing the upstream-bandwidth of mobile nodes.It uses an adaptive rearrangement of a node's concurrent uploading transfers,which causes the count of the node's concurrent uploading transfers to lower while ensuring that the node's upstream-bandwidth can be efficiently utilized.Our simulations show that,EFS achieves much less dissemination time than other protocols including Bullet Prime and a direct implementation of BitTorrent for mobile environments.展开更多
为更好地使URLLC(Ultra-Reliable and Low Latency Communications)与增强型移动宽带业务(eMBB:enhanced Mobile Broad Band)在同一载波频段有效复用,进一步提升混合业务系统性能,提出一种基于可扩展传输时间间隔(TTI:Transmission Time...为更好地使URLLC(Ultra-Reliable and Low Latency Communications)与增强型移动宽带业务(eMBB:enhanced Mobile Broad Band)在同一载波频段有效复用,进一步提升混合业务系统性能,提出一种基于可扩展传输时间间隔(TTI:Transmission Time Interval)的动态带宽分配策略。系统根据业务类型进行带宽动态划分;时域上提升URLLC调度优先级;频域上采用不同长度的TTI进行以用户为中心的无线资源分配。动态系统级仿真表明,在不同程度的负载水平下,相比传统无线资源分配算法,该方案能在有效满足URLLC用户时延需求的前提下优化eMBB用户的吞吐量消耗,URLLC用户时延增益最高达到83.8%,提升了5G混合业务系统中不同类型业务的服务质量(QoS:Quality of Service)。展开更多
Time synchronization techniques, especially on the pulse per second(PPS) temporal basis, have attracted growing research interests in recent years. In this paper, we have proposed and experimentally demonstrated a hig...Time synchronization techniques, especially on the pulse per second(PPS) temporal basis, have attracted growing research interests in recent years. In this paper, we have proposed and experimentally demonstrated a high-precision two-way time transfer(TWTT) system to realize long-distance dissemination of 1 PPS signal generated by a hydrogen maser. A dense-wavelength-division-multiplexing(DWDM) system and bi-directional erbium-doped fiber amplifiers(Bi-EDFAs) have also been adopted to suppress the impact of Rayleigh backscattering and optimize the signal to noise ratio(SNR) as well. We have theoretically analyzed the systematic delay in detail. The ultimate root mean square(RMS) variation of time synchronization accuracy is sub-26 ps and the time deviation can be reduced to as low as 1.2 ps at 100 s and 0.253 ps at 12 000 s, respectively.展开更多
基金the National High Technology Research and Development Program (863) of China (No.2007AA01Z457)the Science and Technology Youth Qi-ming-xing Program of Shanghai (No.07QA14033)
文摘In 3G networks upgraded with high speed packet access(HSPA) technology,the high access bandwidth and advanced mobile devices make it applicable to share large files among mobile users by peer-to-peer applications.To receive files as quickly as possible is essential for mobile users in file sharing applications,since they are subject to unstable signal strength and battery failures.While many researches present peer-to-peer file sharing architectures in mobile environments,few works focus on decreasing the time spent in disseminating files among users.In this paper,we present an efficient peer-to-peer file sharing design for HSPA networks called efficient file sharing(EFS) for 3G networks.EFS can decrease the dissemination time by efficiently utilizing the upstream-bandwidth of mobile nodes.It uses an adaptive rearrangement of a node's concurrent uploading transfers,which causes the count of the node's concurrent uploading transfers to lower while ensuring that the node's upstream-bandwidth can be efficiently utilized.Our simulations show that,EFS achieves much less dissemination time than other protocols including Bullet Prime and a direct implementation of BitTorrent for mobile environments.
文摘为更好地使URLLC(Ultra-Reliable and Low Latency Communications)与增强型移动宽带业务(eMBB:enhanced Mobile Broad Band)在同一载波频段有效复用,进一步提升混合业务系统性能,提出一种基于可扩展传输时间间隔(TTI:Transmission Time Interval)的动态带宽分配策略。系统根据业务类型进行带宽动态划分;时域上提升URLLC调度优先级;频域上采用不同长度的TTI进行以用户为中心的无线资源分配。动态系统级仿真表明,在不同程度的负载水平下,相比传统无线资源分配算法,该方案能在有效满足URLLC用户时延需求的前提下优化eMBB用户的吞吐量消耗,URLLC用户时延增益最高达到83.8%,提升了5G混合业务系统中不同类型业务的服务质量(QoS:Quality of Service)。
基金supported by the National Natural Science Foundation of China(Nos.61571244 and 61501262)the Science and Technology Project of Tianjin(No.16YFZCSF00540)the Natural Science Foundation of Tianjin(No.15JCYBJC51600)
文摘Time synchronization techniques, especially on the pulse per second(PPS) temporal basis, have attracted growing research interests in recent years. In this paper, we have proposed and experimentally demonstrated a high-precision two-way time transfer(TWTT) system to realize long-distance dissemination of 1 PPS signal generated by a hydrogen maser. A dense-wavelength-division-multiplexing(DWDM) system and bi-directional erbium-doped fiber amplifiers(Bi-EDFAs) have also been adopted to suppress the impact of Rayleigh backscattering and optimize the signal to noise ratio(SNR) as well. We have theoretically analyzed the systematic delay in detail. The ultimate root mean square(RMS) variation of time synchronization accuracy is sub-26 ps and the time deviation can be reduced to as low as 1.2 ps at 100 s and 0.253 ps at 12 000 s, respectively.
