Split smart messages: middleware for pervasive computing on smart phones

Smart Phone is a recently emerged technology that supports Java program execution and provides both short-range wireless connectivity (Bluetooth/IrDA) and Internet connectivity (GPRS/3G). Smart Phones represent the first viable ubiquitous computing devices because they are becoming an integral part of our daily life. Although these phones are closed systems with limited resources, we believe that a multitude of distributed applications in which Smart Phones act as peers in ad hoc networks can be developed. To realize the potential, there is a need for a middleware that supports such applications and a systematic study of the communication/ computation trade-offs. The middleware should provide functionality to support service execution, discovery and migration and should be able to score well on three criteria: portability, security, and performance. To achieve this goal, we have implemented and evaluated Split Smart Messages (SSM), a lightweight middleware architecture similar to mobile agents, that exploits dual connectivity on Smart Phones. Services can be executed, discovered, and migrated on top of the SSM middleware. To facilitate portability, we have designed an execution migration scheme that works on top of unmodified Java virtual machines. To improve upon security while preserving performance, code is uploaded to and downloaded from a trusted web server, while data and state are transferred across the local network. We have implemented an SSM prototype on Sony Ericsson P800/P900 Smart Phones and compared its performance with that achieved on HP iPAQ PDAs.Technical report DCS-TR-56