Distributed Group Communication System for Mobile Devices Based on SMS

This paper presents a group communication system for mobile devices, called DistributedGCS. Mobile communication is slow, expensive and suffers from occasional disconnections, especially when users are moving. DistributedGCS is based on SMS and enables group communication despite these restrictions. It provides all primitives needed for a chat application and handles process failures. As mobile communication is expensive, DistributedGCS is designed for small message overhead and, additionally, exploits SMS based message relaying to handle short-term disconnections. In this work, we present the group maintenance service and the multicast service of DistributedGCS. In order to distribute the overhead of failure discovery over all processes we introduce the concept of a circle of responsibility for failure detection. We discuss informally that DistributedGCS can handle the most common failures properly while keeping the message overhead very low.