Heterogeneous cellular networks(HCNs), by introducing caching capability, has been considered as a promising technique in 5 G era, which can bring contents closer to users to reduce the transmission delay, save scarce...Heterogeneous cellular networks(HCNs), by introducing caching capability, has been considered as a promising technique in 5 G era, which can bring contents closer to users to reduce the transmission delay, save scarce bandwidth resource. Although many works have been done for caching in HCNs, from an energy perspective, there still exists much space to develop a more energy-efficient system when considering the fact that the majority of base stations are under-utilized in the most of the time. Therefore, in this paper, by taking the activation mechanism for the base stations into account, we study a joint caching and activation mechanism design to further improve the energy efficiency, then we formulate the optimization problem as an Integer Linear Programming problem(ILP) to maximize the system energy saving. Due to the enormous computation complexity for finding the optimal solution, we introduced a Quantum-inspired Evolutionary Algorithm(QEA) to iteratively provide the global best solution. Numerical results show that our proposed algorithm presents an excellent performance, which is far better than the strategy of only considering caching without deactivation mechanism in the actual, normal situation. We also provide performance comparison amongour QEA, random sleeping algorithm and greedy algorithm, numerical results illustrate our introduced QEA performs best in accuracy and global optimality.展开更多
Caching can reduce the bandwidth requirement in a mobile computing environment as well as minimize the energy consumption of mobile hosts. To affirm the validity of mobile host' cache content, servers periodically...Caching can reduce the bandwidth requirement in a mobile computing environment as well as minimize the energy consumption of mobile hosts. To affirm the validity of mobile host' cache content, servers periodically broadcast cache invalidation reports that contain information of data that has been updated. However, as mobile hosts may operate in sleeping mode (disconnected mode), it is possible that some reports may be missed and the clients are forced to discard the entire cache content. In this paper, we present a cache invalidation scheme base on mobile agent in mobile computing environments, which can manage consistency between mobile hosts and servers, to avoid losing cache invalidation reports.展开更多
基金jointly supported by the National Natural Science Foundation of China (No.61501042)the National High Technology Research and Development Program(863) of China (2015AA016101)+1 种基金Beijing Nova Program(Z151100000315078)Information Network Open Source Platform and Technology Development Strategy(No.2016-XY-09)
文摘Heterogeneous cellular networks(HCNs), by introducing caching capability, has been considered as a promising technique in 5 G era, which can bring contents closer to users to reduce the transmission delay, save scarce bandwidth resource. Although many works have been done for caching in HCNs, from an energy perspective, there still exists much space to develop a more energy-efficient system when considering the fact that the majority of base stations are under-utilized in the most of the time. Therefore, in this paper, by taking the activation mechanism for the base stations into account, we study a joint caching and activation mechanism design to further improve the energy efficiency, then we formulate the optimization problem as an Integer Linear Programming problem(ILP) to maximize the system energy saving. Due to the enormous computation complexity for finding the optimal solution, we introduced a Quantum-inspired Evolutionary Algorithm(QEA) to iteratively provide the global best solution. Numerical results show that our proposed algorithm presents an excellent performance, which is far better than the strategy of only considering caching without deactivation mechanism in the actual, normal situation. We also provide performance comparison amongour QEA, random sleeping algorithm and greedy algorithm, numerical results illustrate our introduced QEA performs best in accuracy and global optimality.
文摘Caching can reduce the bandwidth requirement in a mobile computing environment as well as minimize the energy consumption of mobile hosts. To affirm the validity of mobile host' cache content, servers periodically broadcast cache invalidation reports that contain information of data that has been updated. However, as mobile hosts may operate in sleeping mode (disconnected mode), it is possible that some reports may be missed and the clients are forced to discard the entire cache content. In this paper, we present a cache invalidation scheme base on mobile agent in mobile computing environments, which can manage consistency between mobile hosts and servers, to avoid losing cache invalidation reports.
