Due to the unpredictability of mobile network, it is difficult to meet transaction deadlines in a mobile distributed real-time database system (MDRDTBS). We propose the idea of transaction shipping to reduce the overheads in processing a transaction over mobile network and in resolving priority inversion. We consider a distributed lock-based real-time protocol, the Distributed High Priority Two Phase Locking (DHP-2PL), to study the impacts of mobile network on real-time data access. A detailed model of a MDRTDBS has been developed, and a series of simulation experiments have been performed to evaluate the performance of our approach.
Kam-yiu Lam, Tei-Wei Kuo, Wai-Hung Tsang, Gary C.