An Updates Dissemination Protocol for Read-Only Transaction Processing in Mobile Real-Time Computing Environments

摘要

Data management issues in mobile computing environments have got lots of concerns of relevant researchers. Among these research topics, data broadcast has been extensively investigated due to its advantages such as scalability and bandwidth effectiveness. While plenty of works have been done on this subject, it is still less touched when data broadcast is used to deliver constantly updated real-time data to read-only transactions with deadlines. In this paper, we first deeply analyze the data dissemination requirements for read-only transaction processing in mobile real-time computing environments and formally define several performance objectives. Then a novel updates dissemina-tion protocol called mixed real-time data broadcast is proposed. In mixed real-time data broadcast, a set of new techniques including reducing the length of consistency intervals, immediate updates dissemination policy and on-demand data delivery are incorporated seamlessly. Moreover, an enhanced index structure is designed for read-only transactions to judge precisely when to request the desired data. Simulation results show that the proposed protocol can provide higher data currency and lower miss rate compared with existing updates dissemination protocols and is more appropriate for mobile real-time computing environments.