Performance Comparison of Scheduling Techniques to Manage Transactions for Real-Time Mobile Databases in Ad Hoc Networks

Resumen

A Mobile Ad-hoc Network (MANET) ¡s an autcnomous system of mobile hosts (MHs) with similar transmission power and computation capabilities that communicate over relatively bandwidth constrained wireless links. Applications such as emergency/rescue operations, conferences/meetings/lectures, dísaster refief efforts, bluetooth (Personal Area Network} and military networks can be conceived as applications of MAIMET due to the fact that they cannot rely on centralized and organized connectivity. In these environment transactions are time-crltical and require to be executed not only correclly but also within their deadlines, that is, the user that submit a transaction would like it to be completed before a certain time in the future. This study focuses on the comparison of four scheduling techniques based on the policy of assigning priorities to transactions on the system. The techniques are: First Come First Serve (FCFS) [1,2], Earliest Deadline (ED) [1,2,5], Least Slack (LS) [1,2,8] and Least Slack Mobile (LSM) proposed in [3] where some modifications to the Least Slack Technique with respect to energy constraints, disoonnection and transaction type (firnVsoft) are considered. Applying these modifications to Earliest Deadline, the performance of the system will be evaluated to measure the percentage of transaction missing deadlines and the total energy consumption in the mobile hosts. The performance evaluation of the techniques will be carried out by means of simulation. The simulation model is implemented using Visual Slam/Awesim [7].