PRS Subframe Configuration in Dynamic TDD Networks
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Solution Overview
Problem
In dynamic Time Division Duplex (TDD) systems, the unpredictable assignment of flexible subframes can lead to inconsistent transmission of Positioning Reference Signals (PRS), degrading Observed Time Difference Of Arrival (OTDOA) positioning performance and failing to meet regulatory requirements for emergency services, as PRS subframes may not be guaranteed, causing delays and inaccuracies in user equipment (UE) location determination.
Innovation Solution
A method is implemented in network nodes, positioning nodes, and user equipment to dynamically determine and manage PRS transmission configurations, comparing parameters related to PRS transmission with thresholds to ensure that subframes intended for PRS are maintained as downlink subframes, rather than being converted to flexible subframes, thereby ensuring consistent and accurate positioning measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If flexible subframes are used to dynamically adapt uplink/downlink configuration, then system adaptability and traffic flexibility are improved, but PRS transmission reliability deteriorates because PRS subframes cannot be consistently guaranteed
Solution Approach 1:
The patent extracts PRS subframes from the flexible subframe pool and designates them as fixed downlink subframes. This separation ensures that PRS transmissions occur in dedicated, non-flexible subframes, guaranteeing their availability while allowing other subframes to remain flexible for traffic adaptation.
Solution Approach 2:
The patent segments the subframe structure into fixed downlink subframes (for PRS transmission) and flexible subframes (for dynamic traffic adaptation). This segmentation allows the system to maintain both PRS reliability and traffic flexibility by assigning different functions to different subframe types.
2Productivity
If PRS periodicity is increased to reduce measurement frequency, then network resource usage is improved, but RSTD measurement time increases causing positioning delays
Solution Approach 1:
The patent performs preliminary configuration of PRS subframes as fixed downlink subframes before positioning measurements are needed. This advance preparation ensures that PRS subframes are always available when required, eliminating measurement delays while maintaining efficient periodicity.
3Adaptability or versatility
If flexible subframes are used for traffic adaptation, then uplink/downlink capacity flexibility is improved, but positioning measurement accuracy deteriorates due to insufficient PRS subframe availability
Solution Approach 1:
The patent applies local quality by designating specific subframes (PRS subframes) with fixed downlink direction and PRS transmission capability, while other subframes maintain flexible direction. This localized fixation of PRS subframes ensures their availability for accurate positioning measurements while preserving overall system flexibility.
Data Source
AI summary
The present embodiments relate to a network node (90), a method thereof; a positioning node (100), a method thereof; a UE (110) and a method thereof, for handling transmission of a reference signal and/or a reference signal configuration. The method in the network node (90) comprises: determining a transmission configuration for use in a cell served by the network node; if at least one subframe containing said reference signal is also configured as a flexible subframe, comparing at least one parameter related to the transmission configuration with a threshold, and deciding based on the result of said comparison whether to operate the at least one subframe as a flexible subframe or as a downlink subframe.