Over-the-Air Antenna Reference Point Synchronization
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Solution Overview
Problem
Existing wireless communication networks face challenges in achieving precise network synchronization, particularly in radio access network nodes, due to timing errors and limitations in current synchronization methods such as GNSS and PTP, which are affected by environmental conditions and network asymmetries, making it difficult to achieve sub-microsecond accuracy without significant cost escalation.
Innovation Solution
Implementing Over-The-Air Time synchronization between radio access network nodes by exchanging synchronization reference signals directly between antenna reference points using existing wireless communication resources, optimizing signal transmission and reception to minimize interference and asymmetry, and utilizing Zadoff-Chu or Gold sequences for efficient signal detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional synchronization methods (GNSS/PTP) are used to regulate radio access network node clocks to CRT, then network synchronization is achieved, but timing errors accumulate and sub-microsecond accuracy is difficult to achieve without cost escalation
Solution Approach 1:
The patent extracts the synchronization function from the centralized CRT-based system to a distributed peer-to-peer system where ARPs directly exchange timing information. This eliminates the need for complex centralized synchronization infrastructure and reduces accumulated timing errors by establishing direct timing relationships between neighboring nodes.
Solution Approach 2:
The patent introduces synchronization reference signals as intermediaries that carry timing information between ARPs. These reference signals enable precise time transfer without requiring direct physical connection or complex protocol exchanges, simplifying the synchronization mechanism while achieving sub-microsecond accuracy.
2Ease of operation
If PTP protocol is used for time distribution over backhaul network, then CRT is delivered to radio access network nodes, but network asymmetry and limited timestamp resolution cause timing errors
Solution Approach 1:
The patent replaces the PTP protocol-based mechanical timestamp exchange mechanism with a wireless signal-based timing transfer system. By using synchronized radio frequency reference signals between ARPs, the system achieves higher precision without being constrained by network path asymmetries or timestamp resolution limitations.
3Reliability
If GNSS receivers are deployed at radio access network nodes to provide local CRT reference, then time alignment is achieved, but GNSS signal availability is limited indoors and in tunnels
Solution Approach 1:
The patent merges the synchronization function into the existing wireless communication infrastructure by using ARPs that are already present at radio access network nodes. This eliminates the need for separate GNSS receiver deployments and enables synchronization in all locations where wireless coverage exists, including indoors and tunnels.
4Ease of manufacture
If synchronization reference signals are exchanged between ARPs using existing wireless communication resources, then cost-effective synchronization is achieved, but resource allocation and interference management become complex
Solution Approach 1:
The patent makes existing wireless communication resources serve dual purposes: both data transmission and synchronization reference signal exchange. By utilizing the same radio frequency resources and ARP infrastructure for both functions, the system achieves cost-effective deployment without requiring dedicated synchronization hardware or frequency bands.
Data Source
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AI summary
Disclosed is a method for synchronizing transmission of signals from antenna reference points, ARP, (121, 122) of a wireless communication network (100). The method comprises initiating transmission of a first synchronization reference signal from a first ARP (121) at a first time point, instructing a second ARP (122) to determine a second time point for reception of the first synchronization reference signal, initiating transmission of a second synchronization reference signal from the second ARP (122) at a third time point, and instructing the first ARP to determine a fourth time point for reception of the second synchronization reference signal. The first and the second synchronization references signals are either transmitted in uplink communication resources available or they are transmitted in downlink communication resources. The method further comprises initiating transmission of data from the first ARP (121) to wireless devices (130) at a time point determined based on the first, second, third and fourth time points.