Design and evaluation of network reconfiguration protocols for mostly-off sensor networks

Abstract

A new class of sensor network applications is mostly off. Exemplified by Intel's FabApp, in these applications the network alternates between being off for hours or weeks, then activating to collect data for a few minutes. While configuration of traditional sensornet applications is occasional and so need not be optimized, these applications may spend half their active time in reconfiguration every time when they wake up. Therefore, new approaches are required to efficiently "resume" a sensor network that has been "suspended" for long time. This paper focuses on the key question of when the network can determine that all nodes are awake and ready to communicate. Existing approaches assume worst-case clock drift, and so must conservatively wait for minutes before starting an application. We propose two reconfiguration protocols to largely reduce the energy cost during the process. The first approach is low-power listening with flooding, where the network restarts quickly by flooding a control message as soon as the first node determines that the whole network is up. The second protocol uses local update with suppression, where nodes only notify their one-hop neighbors, avoiding the cost of flooding. Both protocols are fully distributed algorithms. Through analysis, simulation and testbed experiments, we show that both protocols are more energy efficient than current approaches. Flooding works best in sparse networks with 6 neighbors or less, while local update with suppression works best in dense networks (more than 6 neighbors).

PEARSH: A power efficient algorithm for raising sensor half-life with wireless battery recharge module

“…In their work, Li et al [11] identified with the mostly-off approach of Intel's Fab project. As a modification, they presented a low-power listening with flooding, as well as local update with suppression as a means of reducing latency and cost of flooding respectively, while enjoying the benefits of sleeping nodes.…”

“…As a modification, they presented a low-power listening with flooding, as well as local update with suppression as a means of reducing latency and cost of flooding respectively, while enjoying the benefits of sleeping nodes. Low power listening involves the periodic sampling of a channel by taking one or a few signal strength samples [11].…”

A Novel Algorithm for Maximizing the Lifetime of Sensor Networks and the Use of an m²-Mote to Refresh Battery Power On-the-Fly

“…, (1) where n is the WSN designer defined cluster size and {p} refers to the nearest integer derived from the value p. The "-1" in the equation above is to account for the sink node which is not going to be part of any cluster. The other sequential PEARSH steps are as follows:…”

BailighPulse: A low duty cycle data gathering protocol for mostly-off Wireless Sensor Networks

“…In this paper we address the problem of energy ecient data gathering in mostly-o sensor networks applications [1]. It is assumed that the data from the sensor network is collected periodically at very low rates, i.e., greater than tens of minutes.…”

“…We apply a polling period optimization scheme similar to the one proposed in [1]. Polling during the synchronization phase of BailighPulse is optimized with respect to the protocol duty cycle:…”