NSF Research Grant



Energy Efficient Communication in Sensor Networks

Project Summary

Spurred by the rapid increase in capabilities (and the declining cost) of computing and communication devices, it has become increasingly viable to embed sensors to physical devices and link these sensors through wireless networks. These sensor networks can be deployed for a wide range of applications that can improve our overall quality of life, efficiency, and even our ability to save lives. These applications include healthcare (e.g., health monitoring and coordination among doctors and nurses), aircraft flight control, weather forecasting, home appliance control, and protection against bioterrorism. One of the key challenges in the deployment of sensor networks is how to prolong the lifetime of the networks. Sensor networks will stress power sources because of their need for long operating lifetimes and high energy density. Therefore, energy efficiency is critical for the wide deployment of sensor networks.

We propose to study energy management techniques for sensor networks. Our key idea is to take advantage of the physical layer design that facilitates the combining of partial information.  A node can receive several partial signals and combine these signals to retrieve the complete signal. We refer to this as hitchhiking. Hitchhiking can potentially conserve energy for transmitting data in sensor networks. By effective use of partial signals, a packet can be delivered with less nodes and/or less transmission power at each node. We propose to systematically study the energy management techniques for sensor networks as follows. 

  • Physical layer design of hitchhiking: We plan to study the physical layer design of hitchhiking. In particular, we will develop energy-efficient techniques for timing acquisition, preamble design, and packet scheduling in interference-limited environments. The goal is to minimize the resources and overhead needed to facilitate hitchhiking. We will systematically evaluate the tradeoff between resources needed for hitchhiking and energy reduction for transmission.

  • Power-aware broadcast: We plan to study power control for broadcast networks. In particular, we will explore both centralized and localized algorithms for energy-efficient broadcast. Both uniform and non-uniform transmission power are considered in the design. We will evaluate the performance of the sensor network in terms of both energy consumption and throughput.

  • Power-aware unicast: We plan to study power control for unicast networks. In particular, we will investigate both centralized and localized algorithms for energy efficient unicast. The key challenge of unicast is how to maintain the robustness of the network by adaptively routing according to power level of relay nodes. We will evaluate the performance of the energy saving resulted from hitchhiking and potential enhancement to the lifetime of the network.

  • Power saving protocols: We plan to study power saving protocols to reduce the energy consumption for idle modes. In particular, we will minimize the number of nodes that are in the power saving mode by constructing a dominating set that covers all nodes under hitchhiking. Nodes can adaptively switch between the power saving mode and the sleep mode to prolong the lifetime of the network.

The PIs have active collaborations with Motorola and Microsoft. We plan to continue our collaborations with our industrial partners. The proposed project on energy efficient sensor networks cuts cross the boundaries between communication and network design. Our project will have a significant educational impact. We will design and offer courses and seminars on interdisciplinary examination of energy efficient design. In addition, we will involve both graduate and undergraduate students (including women and minorities) in our research projects.

Contador    Since July 2003