An Example Schedule Time Leaf Leaf Sink 0 Sleeping 2 Node 1 Node2 Node3 Hop 0 Hop 1 Hop 2 Hop 2 Transmission PL/R Q/M Active (sink only) Routing tree 1 3 0
Energy Efficiency DCS achieves 50-60% energy saving.
Summary on Scheduling
Scheduling is done on one or more layers.
Scheduling is crucial for performance.
Coordination of nodes
Different transmission timings of neighboring nodes result in different delays.
Scheduling and Sensor Databases
SensorDBs are complex to schedule.
Opportunities in scheduling for sensorDBs
On-node multi-query scheduling
Changing sensor environments
Query-aware transmission scheduling
Interaction between scheduling and query execution
Common SensorDB software architecture
Operating system support
Summary and future directions
System design issues have a significant impact on the overall performance of sensor databases.
A holistic sensor database system requires considerations on all layers – from OS kernel, MAC, routing to query processing.
Cross-layer design is necessary, especially in scheduling.
Multi-query processing in sensor networks
Sharing, caching, and pipelining
Queries, operators, and transmission
In-network joins among different nodes
Fine-grained scheduling for node cooperation
Query processing in multi-sink networks
Cross-layer design is necessary for an efficient, holistic sensor database.
References: Sensor Databases and Runtime Support
[BGS01] Philippe Bonnet, Johannes Gehrke, and Praveen Seshadri. Towards Sensor Database Systems. MDM, 2001 .
[MF+02] Samuel Madden, Michael J. Franklin, Joseph M. Hellerstein, and Wei Hong. TAG: a Tiny AGgregation Service for Ad-Hoc Sensor Networks. OSDI , 2002.
[MF+03] Samuel Madden, Michael J. Franklin, Joseph M. Hellerstein, and Wei Hong. The Design of an Acquisitional Query Processor for Sensor Networks . SIGMOD , 2003.
[YG03] Yong Yao and Johannes Gehrke. Query Processing for Sensor Networks. CIDR , 2003.
[MAK07] Rene Muller, Gustavo Alonso, and Donald Kossman. SwissQM: Next Generation Data Processing in Sensor Networks. CIDR, 2007.
[CP+07] David Chu, Lucian Popa, Arsalan Tavakoli, Joseph M. Hellerstein, Philip Levis, Scott Shenker, and Ion Stoica. The Design and Implementation of A Declarative Sensor Network System . Submitted for publication , 2007.
References: OS Support
[DGV04] Adam Dunkels, Björn Grönvall, and Thiemo Voigt. Contiki - A Lightweight and Flexible Operating System for Tiny Networked Sensors . The 29th Annual IEEE Conference on Local Computer Networks , 2004.
[HK+05] Chih-Chieh Han, Ram Kumar, Roy Shea, Eddie Kohler and Mani Srivastava. A Dynamic Operating System for Sensor Nodes. International Conference on Mobile Systems, Applications, and Services , 2005.
[BC+05] Shah Bhatti, James Carlson, Hui Dai, Jing Deng, Jeff Rose, Anmol Sheth, Brian Shucker, Charles Gruenwald, Adam Torgerson, and Richard Han. MANTIS OS: An Embedded Multithreaded Operating System For Wireless Micro Sensor Platforms. ACM/Kluwer Mobile Networks and Applications (MONET), Special Issue on Wireless Sensor Networks , vol. 10, no. 4, pp.563–579, Aug 2005.
[GS06] Lin Gu and John A. Stankovic. t-kernel: Providing Reliable OS Support for Wireless Sensor Networks. SenSys , 2006.
References: MAC and Routing
[STS02] Curt Schurgers, Vlasios Tsiatsis, and Mani B. Srivastava. STEM: Topology Management for Energy Efficient Sensor Networks . IEEE Aerospace Conference , 2002.
[YHE02] Wei Ye, John Heidemann, and Deborah Estrin. An Energy-Efficient MAC Protocol for Wireless Sensor Networks . INFOCOM , 2002.
[DL03] Tijs van Dam and Koen Langendoen. An Adaptive Energy-Efficient MAC Protocol for Wireless Sensor Networks . SenSys, 2003.
[IGE00] Chalermek Intanagonwiwat, Ramesh Govindan, and Deborah Estrin. Directed Diffusion: A Scalable and Robust Communication Paradigm for Sensor Networks. MobiCom , 2000.
[WTC03] Alec Woo, Ternence Tony, and David Culler. Taming the Underlying Challenges of Reliable Multihop Routing in Sensor Networks. SenSys , 2003.
[HDB04] Barbara Hohlt, Lance Doherty, and Eric Brewer. Flexible Power Scheduling for Sensor Networks . IPSN , 2004.
[Sic04] Mihail L. Sichitiu. Cross-Layer Scheduling for Power Efficiency in Wireless Sensor Networks . INFOCOM , 2004.
[WLX06] Hejun Wu, Qiong Luo, and Wenwei Xue. Distributed Cross-Layer Scheduling for In-Network Sensor Query Processing . PerCom , 2006.