The execution process of satellite-ground clock synchronization and ephemeris uploading in the system is analyzed,as well as their characterized operation and their relationship.Based on the analysis of the scheduling...The execution process of satellite-ground clock synchronization and ephemeris uploading in the system is analyzed,as well as their characterized operation and their relationship.Based on the analysis of the scheduling goal and constraint character,a heuristics rule-based multi-stage link scheduling algorithm was put forward.The algorithm distinguishes the on-off-frontier satellites from the others and schedules them by turns.The paper presented the main flow as well as the detailed design of the rule.Finally based on the current COMPASS global system,some typical resources and constraints are selected to generate an instance.Then the comparison analysis between the heuristics scheduling algorithm and three other traditional scheduling strategies are carried out.The result shows the validity and reasonability of the multi-stage strategy.展开更多
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
基金National Natural Science Foundations of China(Nos.71201171,71501179)
文摘The execution process of satellite-ground clock synchronization and ephemeris uploading in the system is analyzed,as well as their characterized operation and their relationship.Based on the analysis of the scheduling goal and constraint character,a heuristics rule-based multi-stage link scheduling algorithm was put forward.The algorithm distinguishes the on-off-frontier satellites from the others and schedules them by turns.The paper presented the main flow as well as the detailed design of the rule.Finally based on the current COMPASS global system,some typical resources and constraints are selected to generate an instance.Then the comparison analysis between the heuristics scheduling algorithm and three other traditional scheduling strategies are carried out.The result shows the validity and reasonability of the multi-stage strategy.
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.
