Updates Dissemination in Mobile Real-Time Database Systems

Data broadcast is a widely accepted data dissemination method for mobile computing systems and has held a lot of interest of relevant researchers. When data broadcast is used to disseminate frequently-updated data it is called updates dissemination. Existing updates dissemination protocols are unsuitable for mobile real-time read-only transaction processing because they don't consider the real-time constraints on both data and transactions in mobile real-time database systems. In this paper a new updates dissemination protocol called hybrid forward multi-version data broadcast(HFMVB) is proposed. HFMVB not only guarantees the consistency of read-only transactions，it also provides higher data currency and lower miss rate by shortening the consistency interval, instantly broadcasting updates and utilizing broadcast on-demand. Simulation results show that HFMVB has better performance compared with the existing updates dissemination protocols and is more appropriate for mobile real-time database systems.