1. Off By One Power-Save Protocols Corey Andalora Keith Needels

2. Agenda Topic explanation Problem description Proposed project Citations Summary

3. Power-Save Protocols Motivation  We want to maximize the battery life of network devices.  Radios consume a large fraction of device power.  Simply idling uses almost as much energy as receiving data. Transmitting data can use as little as 34% more energy than idling or as much as 100% more energy.

4. Power-Save Protocols Solution?  Put radios into sleep mode when they do not need to transmit or receive data.  This is not trivial – if everyone is asleep, how can data be routed through the network?  Several protocols have been developed for efficiently putting devices into the sleep state while maintaining routing capability. These are the protocols we will be investigating.

5. Project Goal Implement various(1-3) power-save algorithms that would ultimately reduce the amount of power consumed by an ad-hoc network. Evaluate the test results against each other and a baseline to determine their strengths and weaknesses.

6. Project Approach Produce an environment for simulating an ad-hoc network utilizing one or more of the researched algorithms. Potential inputs  Initial device positions in coordinate system  Device speed vectors to simulate movement  Average on/off time of devices  Power levels, consumption rate, etc. Outputs  Average routing time per packet  Overall power consumption of network

7. Project View A C B D E F

8. Project Analysis We plan to compare the implementation of our algorithms against each other as well as the baseline system which never sleeps. We shall graph the results and show the power saved using the tested algorithms as well as the latency that has resulted.

9. Span Finds a dominating subset of the network topology. Only devices in this subset need to awake at all times, and the other devices can alternate between the sleep state and active states. The dominating subset can change when devices become low on power. Citation:  Benjie Chen, Kyle Jamieson, Hari Balakrishnan, and Robert Morris. “Span: An energy-efficient coordination algorithm for topology maintenance in ad hoc wireless networks.” ACM Wireless Networks Journal, 8(5), 481-494, September 2002.

10. GAF Arranges geographically aware nodes into grids, where each node in a grid square is in range of nodes in adjacent grid squares. Only one node in each square needs to be active at any time, and the active node can change over time. Citation:  Ya Xu, John Heidemann, and Deborah Estrin. “Geography-informed energy conservation for ad hoc routing,” in Proceedings of 7 th Annual International Conference on Mobile Computing and Networking, pp. 70-84, July 2001.

11. BECA Nodes independently transition to the idle state and back to the sleep state. When a node receives traffic, it will wait some time before going back into the sleep state. Routing is done with an on-demand flooding protocol. Citation:  Ya Xu, John Heidemann, and Deborah Estrin. “Adaptive energy-conserving routing for multi-hop ad hoc networks.” Technical Report 527, USC/Information Sciences Institute, October 2000.

12. Summary We are researching power-save protocols for ad hoc networks. We are implementing an ad-hoc simulation to test these algorithms. We will graph the results and determine their pros and cons. Questions?