Energy-efficient distributed algorithms for wireless ad hoc networks Ramki Gummadi (MIT)

CW Protocols: Two traditional areas Battery conservation for ad hoc n/w Disconnected routing, forwarding Energy-efficient multicast Sensor networks Energy-aware communication Data-centric storage Data-centric routing

CW Energy-efficiency claims No good way to measure energy communication Measuring energy at the radio? Measuring energy consumed by sensors? Packetized abstraction for radios Power consumption of real radios is non- linear function of message count or distance

CW New approaches Low-power listen Make MAC long Synchronize on wake-ups Communication by silences Sender and receiver wait for n clock cycles to communicate data value n Linear in value of n

CW In-network computing algorithms Store data within network Data-centric Storage (DCS) Rendezvous based on mapping data values to nodes Good for continuous queries, bad for one- shot queries

CW In-network computing algorithms (contd..) Route queries to internal nodes instead of collecting data at a central server Lots of papers (Starting from Directed Diffusion) Hard to deal with failures, data integrity temp=70

CW Challenge for energy-efficient algorithms Mismatch between app requirements and protocol guarantees Sensor networks want data integrity guarantees Requires all data to be transported out of the sensor network For bulk data, use faster radio with higher power, range or lossy multi-hop?