Design and Implementation of a Short Message Service Data Channel for Mobile Systems∗

The Short Message Service (SMS) is one of the most ubiquitous wireless technologies on Earth. Each year hundreds of billions of messages are sent, demand continues to grow, and competition between cellular providers is driving prices down. These trends create practical opportunities for the use of SMS in mobile systems. In this paper we present the design and implementation of an SMS-based data channel, or SMS-NIC, that is lightweight and runs on multiple mobile platforms. Through integration with an existing mobile platform, we show that the SMS-NIC has little operational overhead and provides efficient, reliable transport for large messages send over the cellular network, where message losses frequently occur. We motivate the design of the SMS-NIC through a characterization of SMS using workloads consisting of bursts of messages between sender and receiver. This analysis differs from previous SMS studies by focusing on transmission patterns that differ from normal cell phone use. Through this characterization we show that message delay and message loss are affected by the transmission order, the time of day has minimal effect on transmission rate, delay, and loss, and that losses and high delays significantly outweigh the rate or message reordering.