PHY-layer link quality indicators for wireless networks using matched-filters

TL;DR

This paper introduces a simple, real-time method for estimating wireless link quality using matched-filtering techniques that detect packet components without decoding, validated through extensive SDR experiments.

Contribution

It presents a novel, low-complexity approach to link quality estimation based on matched-filtering of packet preambles and headers, applicable in interference-prone environments.

Findings

Effective detection of packet transmissions in real-time

Robust performance under strong interference and low SNR

Applicable to 802.15.4 (Zigbee) networks

Abstract

We present a novel approach to accurate real-time estimation of wireless link quality using simple matched-filtering techniques. Our approach is based on the simple observation that there is a portion of each packet transmission from any given node that does not change from one packet to another; this includes preamble sequences used to synchronize the receiver and also address information in the packet header used for medium access control and routing. Our approach can be thought of as a generalized and simplified variant of standard signal processing techniques that are commonly used for preamble detection, automatic gain control, carrier sensing and other functions in many packet wireless networks. By using a combination of energy detection and correlation techniques, we show that we can effectively detect packet transmissions in real-time with low complexity, without decoding the packets themselves, and indeed, even without detailed knowledge of the packet format. We present extensive experimental results from a software-defined radio testbed to illustrate the effectiveness of this approach for 802.15.4 (Zigbee) networks even in the presence of strong interference signals and low SNR.