Ns-level time transfer over a microwave link using the PTP-WR protocol

Today it is possible to achieve sub-ns level time synchronization on a wireline network while only us-level synchronization can be achieved on a wireless (microwave) link. In this paper we will, first, study the performances of different time synchronization wireline based protocols, such as Precision Time Protocol (PTP), Synchronous Ethernet (SyncE) and PTP White Rabbit (PTP-WR). And then, we will present our results using a wireless link, and determine which radio technology can achieve ns range time synchronization. Our motivation is to qualify a time transfer process operating over microwave link and offering secured GNSS-like time performance.

I. Introduction

An increasing number of infrastructures require an accurate time reference, such as telecommunication base stations, energy industries (smart grid synchronization), and electronic intelligence systems. A GNSS receiver can provide an accurate time and frequency reference, but it requires a line-of-sight link to the satellites, and it has acknowledged vulnerabilities [1]–[4]. Therefore in some critical applications, a “GNSS-free” reference becomes mandatory [5].