Crocs: Cross-Technology Clock Synchronization for WiFi and ZigBee

TL;DR

Crocs introduces a novel method for direct cross-technology clock synchronization between WiFi and ZigBee devices, achieving sub-millisecond accuracy without relying on gateway-based solutions.

Contribution

This paper presents the first study and implementation of direct cross-technology clock synchronization for heterogeneous wireless devices using beacon signals and timestamp transmission.

Findings

Synchronization error below 1 millisecond

Effective cross-technology communication methods evaluated

Insights into accuracy and overhead of different methods

Abstract

Clock synchronization is a key function in embedded wireless systems and networks. This issue is equally important and more challenging in IoT systems nowadays, which often include heterogeneous wireless devices that follow different wireless standards. Conventional solutions to this problem employ gateway-based indirect synchronization, which suffers low accuracy. This paper for the first time studies the problem of cross-technology clock synchronization. Our proposal called Crocs synchronizes WiFi and ZigBee devices by direct cross-technology communication. Crocs decouples the synchronization signal from the transmission of a timestamp. By incorporating a barker-code based beacon for time alignment and cross-technology transmission of timestamps, Crocs achieves robust and accurate synchronization among WiFi and ZigBee devices, with the synchronization error lower than 1 millisecond. We further make attempts to implement different cross-technology communication methods in Crocs and provide insight findings with regard to the achievable accuracy and expected overhead.