Whisper: Fast Flooding for Low-Power Wireless Networks

TL;DR

Whisper is a protocol that enhances flooding speed and reduces radio-on time in low-power wireless networks by using continuous transmission of identical messages, improving network lifetime and efficiency.

Contribution

Whisper introduces a novel continuous transmission flooding method that eliminates gaps between messages, significantly increasing speed and energy efficiency over existing protocols like Glossy.

Findings

Achieves 2x lower radio-on time compared to Glossy

Maintains comparable reliability in data flooding

More than doubles network lifetime when embedded in data collection applications

Abstract

This paper presents Whisper, a fast and reliable protocol to flood small amounts of data into a multi-hop network. Whisper makes use of synchronous transmissions, a technique first introduced by the Glossy flooding protocol. In contrast to Glossy, Whisper does not let the radio switch from receive to transmit mode between messages. Instead, it makes nodes continuously transmit identical copies of the message and eliminates the gaps between subsequent transmissions. To this end, Whisper embeds the message to be flooded into a signaling packet that is composed of multiple packlets -- where a packlet is a portion of the message payload that mimics the structure of an actual packet. A node must intercept only one of the packlets to detect that there is an ongoing transmission and that it should start forwarding the message. This allows Whisper to speed up the propagation of the flood, and thus, to reduce the overall radio-on time of the nodes. Our evaluation on the FlockLab testbed shows that Whisper achieves comparable reliability but 2x lower radio-on time than Glossy. We further show that by embedding Whisper in an existing data collection application, we can more than double the lifetime of the network.