Wireless Node Time Sync via Terrestrial Signal Weighting
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Solution Overview
Problem
Current time synchronization methods in wireless communications networks, such as those using GPS, are vulnerable to interference, lack precision, and require costly infrastructure investments, failing to meet high accuracy requirements for technologies like 5G/NR and LTE-TDD.
Innovation Solution
A method involving a first network node that detects broadcasted time reference signals from systems like LORAN-C, eLORAN, or DCF77, and combines these with positioning signals to determine a synchronized time reference using weighted averages based on node distances, enhancing robustness and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If GPS is used for time synchronization, then time reference is available globally, but the signal is vulnerable to interference and jamming
Solution Approach 1:
The patent introduces an intermediary system (terrestrial time reference network with synchronized clocks at multiple locations) that mediates between the vulnerable GPS signal and the need for reliable time synchronization. This intermediary provides alternative time reference paths that are not susceptible to GPS jamming, allowing network nodes to obtain accurate time references even when GPS is blocked or interfered with.
Solution Approach 2:
The patent changes the parameter of time reference source from satellite-based GPS to terrestrial-based synchronized clocks. By distributing time reference sources across multiple terrestrial locations and using time difference of arrival (TDOA) calculations, the system achieves GPS-like global availability without the vulnerability to signal jamming, as terrestrial signals can be transmitted with higher power and better control.
2Measurement precision
If hardware timing protocol is installed in radio base stations and core network, then time synchronization control is improved, but large investments in network equipment are required
Solution Approach 1:
The patent creates a virtual timing protocol infrastructure by distributing synchronized time reference information through existing communication channels. Instead of installing specialized hardware timing protocol equipment at each base station, the system copies time reference data from terrestrial synchronized clocks and distributes it through standard communication infrastructure, achieving high precision synchronization without expensive dedicated hardware.
Solution Approach 2:
The patent makes existing communication infrastructure multi-functional by using standard communication channels for both data transmission and time reference distribution. The terrestrial time reference network uses existing network infrastructure to carry both operational traffic and synchronization signals, eliminating the need for separate dedicated timing hardware and reducing overall system complexity and cost.
3Reliability
If timing protocol is used for time synchronization, then control over wired communications network is required, but operator control requirements limit deployment flexibility
Solution Approach 1:
The patent enables network nodes to self-determine their time references by receiving signals from multiple terrestrial synchronized clocks and autonomously calculating the best time reference using TDOA methods. This self-service approach eliminates the need for centralized control over the wired communication infrastructure, as each node independently achieves synchronization without requiring operator-managed timing protocol infrastructure.
Solution Approach 2:
The patent inverts the traditional timing architecture by having time reference sources distributed throughout the network rather than centralized in a core network timing server. Instead of the core network distributing time to base stations through controlled channels, independent terrestrial clocks throughout the network provide time references that base stations autonomously select and use, reversing the control hierarchy and increasing deployment flexibility.
Data Source
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AI summary
A method performed by a first network node (110) for determining a synchronized time reference in a wireless communications network (100) is provided. The first network node (110) determine a first timing reference (t3) by detecting a broadcasted time reference signal (S1). Also, the first network node (110) receive information indicating a first timing difference (Δt21-22) between a second timing reference (t21) that is based on a detection of the broadcasted time reference signal (S1) at a second network node (111) and a third timing reference (t22) that is based on a positioning signal (S2) received by the second network node (111). Then, the first network node (110) determine a time reference for the first network node (110) based on the determined first timing reference (t3) and the received first timing difference (Δt21-22). A first network node (110) for determining a timing reference in a wireless communications network (100) is also provided. Furthermore, a second network node (111) and a method performed therein for enabling a synchronized time reference in a wireless communications network (100) are also provided.