UE TOA Positioning in Distributed RAN With Clock Delay Compensation
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Solution Overview
Problem
The distributed RAN/cloud system architecture introduces timing and synchronization issues that impact the accuracy of time of arrival (TOA) propagation delay measurements due to asynchronous eCPRI interfaces and long distances between DU and RU components, leading to variable and unpredictable delays.
Innovation Solution
A new algorithm for TOA T0 calculation in the base station that compensates for reference clock discrepancies between DU and RU, using the over-the-air transmission time (Ra) as a reference, and includes a factor Δ(Ta;Tb) to correct for timing errors, enabling accurate TOA-based propagation delay measurements in distributed RAN/cloud systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If distributed RAN/cloud system architecture is used, then system flexibility and scalability are improved, but timing synchronization accuracy deteriorates due to asynchronous eCPRI interfaces and long distances between DU and RU components
Solution Approach 1:
The patent introduces an intermediary mechanism (reference signal transmission with timing information) between DU and RU to synchronize timing despite the asynchronous eCPRI interface. The DU transmits reference signals with embedded timing information to the RU, which then uses this information to align its transmission timing, effectively mediating the timing synchronization problem in the distributed architecture.
Solution Approach 2:
The patent changes the timing reference parameter from a fixed centralized clock to a dynamic reference signal-based timing mechanism. By using reference signals transmitted over the air with embedded timing information (Ta, Tb, Tair), the system adapts timing synchronization to the actual propagation conditions and component distances, rather than relying on a fixed clock that becomes inaccurate over long distances in distributed architectures.
2Productivity
If distributed RAN/cloud system architecture is used, then deployment scalability is improved, but TOA propagation delay measurement accuracy deteriorates due to variable and unpredictable delays
Solution Approach 1:
The patent implements a feedback mechanism where the UE measures the reference signal reception timing (T1) and reports it back to the network. The network uses this feedback information along with the transmitted reference signal timing (T0) to calculate and compensate for propagation delays. This closed-loop feedback approach enables accurate TOA measurements even in distributed architectures with variable delays.
Solution Approach 2:
The patent performs preliminary timing alignment by having the DU transmit reference signals with pre-calculated timing information (Ta, Tb, Tair) before actual TOA measurements are taken. This preliminary action establishes a known reference point that accounts for the distributed architecture's variable delays, enabling subsequent accurate TOA measurements.
3Measurement precision
If reference clock synchronization is implemented between DU and RU, then timing accuracy is improved, but device complexity increases due to additional synchronization mechanisms
Solution Approach 1:
The patent enables the RU to self-adjust its timing based on reference signals received from the DU. Instead of requiring complex centralized clock distribution and active synchronization control, the RU autonomously aligns its transmission timing by processing the reference signals and extracting timing information (Tair), thereby achieving timing accuracy through self-service rather than complex external control.
Data Source
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AI summary
Example embodiments provide a method to determine a reference signal transmission delay by a base station for a distributed RAN or cloud system architecture. The method uses an over the air transmission time and compensates for a possible reference clock discrepancy. Further, a method for TOA-based propagation delay measurement is provided, where consecutive reference signal transmission delays have a variable pattern or high precision is needed. Apparatuses, methods, and computer programs are disclosed.