Efficient Concurrency Control for Mobile Real-Time Transactions in Data Broadcast Environments

In a wireless data broadcast environment, there is a limited upstream bandwidth from mobile clients to the fixed database server. Traditional concurrency protocols are unsuitable in such an asymmetric communication environment. In this paper, we introduce a concurrency control protocol which integrates optimistic concurrency control and timestamp ordering. A mobile read-only transaction is weak consistent and the serialization graph consisting of all update transactions and a mobile read-only transaction is acyclic. By using this protocol, mobile read-only transactions can execute autonomously and mobile update transactions can detect data conflicts earlier. Extensive simulation experiments are conducted and the result shows that compared with existing concurrency control protocols, more mobile real-time transactions can commit before their deadline expire.