Seminar Topics and Reports

In recent years, cellular networks have witnessed tremendous growth in the use of Short Messaging Service (SMS). In the near future, Multimedia Messaging Service (MMS) is expected to surpass SMS in popularity, traffic, and revenue due to its richer multimedia content such as audio, image and video and greater flexibility. Yet, research in this area has generally been limited, and little is known about the user behavior and system characteristics of mobile messaging. This thesis presents a study of SMS user behavior, and system characteristics based on traces that were collected over the course of three weeks from a nation-wide cellular provider in India that serves over 10 million subscribers. Both message-level and conversation-level messages are characterized, and measurements are presented for person-to-person as well as value-added applicationto- person, and person-to-application services. A statistical study on the failure of SMS messaging is also presented. Last, a dynamic video transcoding system
for MMS video messaging and mobile TV, which takes into consideration the traffic that MMS servers would expect to encounter in the future, is presented and evaluated.

MMS is believed to follow the trend of SMS in terms of popularity; however. MMS messages are substantially larger than SMS messages (about 350 times the size of SMS messages). This implies that the traffic of MMS systems will be much heavier, and it will be necessary to find better techniques for optimization, provisioning and providing improved quality of service for these systems. One such technique is transcoding [STR04, HBL98, FGB96]. Chapter 5 presents a dynamic transcoding proxy for streaming video. This can be used for video clips sent through MMS messages, which are streamed to the recipient’s cellular phone from the MMS server. It can also be used in transcoding for mobile television and streaming movies on cellular phones, which are also expected to become exceedingly popular in future. The rest of this thesis is organized as follows. Chapter 2 introduces the SMS network and its architecture. Chapter 3 presents details about the traces. The results of the trace analysis are presented in chapter 4, including message characteristics, user characteristics and system characteristics, followed by analysis of value-added services, conversational threads, failure of the messages. Chapter 5 describes MMS messaging and presents the design and implementation of the dynamic video transcoding proxy, followed by measurements of the proxy server. Chapter 6 concludes this thesis.