A low power architecture for wireless multimedia systems: lessons learned from building a power hog

UCLA has constructed a network testbed which serves as an environment for developing wireless multimedia systems. The first generation testbed consists of a set of battery powered terminals with low-bit rate video codecs connected to a peer-to-peer multi-hop network over spread spectrum radios. Not surprisingly, this set of features draws considerable current during operation, and achieves a battery life of approximately one hour using a 24 Wh NiMH battery. This report discusses the power consumption of the existing testbed, lessons learned during its development, and a course of action directed to improving battery life for a portable multimedia terminal. The key advancement is the development of a complete system architecture focused on turning off power to components and subsystems. Starting with communications protocols, and progressing up through processors to APIs, this new design extends useful battery life through a significant reduction in current drain.