Digital Signal Forwarding via Timestamp Synchronization
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Solution Overview
Problem
Existing optical transport networks for fronthaul and xhaul applications face challenges in providing low latency and high reliability due to limitations in current protection mechanisms, which are not transparent to CPRI framing and network synchronization, leading to significant latency and jitter.
Innovation Solution
A fault-tolerant mechanism that synchronizes duplicates of digital signals using timestamps and error correction codes, allowing seamless selection of error-free traffic paths without the need for physical protection switches, thereby minimizing detection and switching times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If optical switches are used to physically switch between working and protection paths, then reliability is improved, but latency increases significantly
Solution Approach 1:
The patent replaces mechanical/optical switching systems with electronic processing. Instead of using physical optical switches to select between working and protection paths, the system uses electronic timestamp comparison and error detection code analysis to select error-free signal portions digitally, eliminating mechanical switching latency.
Solution Approach 2:
The patent applies preliminary action by pre-synchronizing duplicate signals using timestamps before any error occurs. The system continuously maintains synchronized copies of signals on both working and protection paths, so when an error is detected, the corrected signal is already prepared and can be immediately selected without switching delay.
2Device complexity
If optical detectors are used to detect signal errors, then device complexity is reduced, but measurement precision deteriorates
Solution Approach 1:
The patent introduces error detection codes as an intermediary mechanism. Instead of directly detecting optical signal quality, the system uses embedded error detection codes that provide precise digital information about signal integrity, enabling accurate error detection without complex optical measurement equipment.
3Reliability
If physical protection switches are implemented, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent eliminates mechanical protection switches by implementing a fully digital selection mechanism. The system uses electronic processing of timestamps and error detection codes to select between working and protection path signals, removing complex mechanical/optical switching hardware while maintaining service continuity through digital signal processing.
4Reliability
If timestamps and error detection codes are used for signal selection, then reliability is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent implements self-service through automatic timestamp-based synchronization. The system autonomously adjusts and maintains synchronization between duplicate signals using embedded timestamps, eliminating the need for external precision calibration equipment and reducing manufacturing precision requirements through self-correcting mechanisms.
Data Source
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AI summary
There is provided a method and device for forwarding a digital signal arranged into portions that each contain a timestamp and an error detection code. Duplicates of the digital signal are received on a first optical path and a second, separate optical path. Corresponding timestamps are identified in the signals and used to synchronize corresponding portions of the signals. The error detection codes in the synchronized portions are used to allow one and only one of the corresponding portions to be selected for forwarding. The selected portions are then forwarded.