Asymmetric Propagation Delay Determination in Wireless Distribution Systems
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Solution Overview
Problem
Wireless distribution systems (WDS) face challenges in accurately determining asymmetric downlink and uplink propagation delays, leading to inaccurate timing advances and location determination for client devices, especially when using different communication mediums.
Innovation Solution
A method and system to determine separate downlink and uplink propagation delays by analyzing signal paths between a central unit and multiple remote units, using a signal source in the central unit to measure propagation delays between two remote units, and establishing propagation delay equations to account for variations in communication mediums.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single propagation delay value is used for both downlink and uplink directions, then the system complexity is reduced, but the location determination accuracy and timing advance precision deteriorate due to asymmetric propagation delays in different communication mediums
Solution Approach 1:
The patent segments the single propagation delay measurement into separate downlink and uplink propagation delay measurements. By using multiple signal paths (downlink path from central unit to remote unit, and uplink path from remote unit to central unit), the system independently measures propagation delays for each direction, accounting for asymmetric characteristics caused by different communication mediums.
Solution Approach 2:
The patent introduces an intermediary measurement approach where the system measures the round-trip propagation delay and separately measures the downlink propagation delay. By subtracting the downlink delay from the round-trip delay, the system derives the uplink propagation delay, thereby obtaining accurate asymmetric delay values without directly measuring each direction separately.
2Measurement precision
If separate downlink and uplink propagation delay measurements are implemented, then the location determination accuracy is improved, but the device complexity and measurement procedures increase
Solution Approach 1:
The patent uses round-trip propagation delay measurement as an intermediary to derive uplink propagation delay. Instead of requiring separate direct measurement apparatus for each direction, the system measures the total round-trip delay and combines it with downlink delay measurement to calculate uplink delay, simplifying the overall measurement system while maintaining accuracy.
Solution Approach 2:
The system implements feedback mechanisms where measured propagation delays are used to adjust timing advances and location determination calculations. The measured downlink and uplink propagation delays are fed back to the central unit to optimize communication timing and positioning accuracy in real-time.
Data Source
AI summary
Embodiments of the disclosure relate to systems and methods for determining asymmetric downlink and uplink propagation delays in a wireless distribution system (WDS) for more accurately determining propagation delay. In this regard, a WDS is configured to determine both the separate downlink and uplink propagation delays between a central unit and a plurality of remote units. It is not presumed that the downlink propagation delay and the uplink propagation delay in the WDS are symmetric to provide a more accurate determination of propagation delay. Therefore, it is possible to determine the downlink and uplink propagation delays with improved accuracy, thus enabling more precise location identification in the WDS.