Ethernet Backhaul Timing Synchronization via Bidirectional Delay Measurement
Solution Overview
Problem
Current methods for measuring one-way frame delay in packet networks, such as Ethernet backhaul, are inaccurate due to asymmetrical paths and do not account for differing latencies in opposite directions, leading to unreliable timing and synchronization.
Innovation Solution
A communication system comprising a Precision Time Protocol (PTP) server, Global Positioning System (GPS), and a pseudowire device that synchronizes timing signals to provide accurate time of day information for time-division multiplexing conversion to Ethernet signals, ensuring redundant and failover-enabled timing and synchronization across the network.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If round trip delay is measured and divided by two to obtain one-way frame delay, then a simple measurement method is achieved, but measurement precision deteriorates due to asymmetrical paths and differing latencies in opposite directions
Solution Approach 1:
The patent segments the timing measurement process into separate forward and reverse direction measurements. Instead of using a single round-trip measurement, the system performs independent timing measurements in each direction (e.g., from network element A to B, and from B to A), allowing accurate capture of asymmetrical path characteristics and differing latencies without requiring complex calculation assumptions.
2Adaptability or versatility
If Ethernet backhaul is used to transport wireless customer traffic, then network versatility and adaptability are improved, but timing and synchronization reliability deteriorates due to inherent packet network variability and asymmetrical paths
Solution Approach 1:
The patent implements bidirectional timing measurements that provide feedback about actual path asymmetry and latency variations. By measuring timing in both directions and using this feedback information, the system can compensate for Ethernet packet network variability and maintain accurate timing and synchronization despite the inherent instability of packet-switched networks.
Data Source
AI summary
A communication system for providing an accurate timing signal and synchronization information is described herein. The communication system comprises a Precision Time Protocol (PTP) server, a Global Positioning System (GPS), a pseudowire device, and a PTP client. The PTP client receives a time of day data and frequency information from the PTP server, receives a timing signal from the GPS, synchronizes the time of day data and timing signal to create synchronized a time of day signal, and provides the synchronized time of day signal to the pseudowire device. The pseudowire device processes the synchronized time of day signal and the frequency information to perform a time-division multiplexing signal to Ethernet signal synchronized conversion.