Idle-Mode UE Positioning with Preconfigured SRS and TA Updates
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Solution Overview
Problem
Existing wireless communication systems face challenges in supporting accurate positioning for user equipment (UE) in idle or inactive mode due to invalid timing advance (TA) and outdated UL transmission spatial filters, leading to interference and increased power consumption.
Innovation Solution
Pre-configure UE with DL and UL reference signal configurations while in a connected state to enable accurate positioning in idle or inactive mode by dynamically updating TA and spatial filters based on UE mobility and directionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If UE transitions to idle or inactive mode for power saving, then power consumption is reduced, but positioning accuracy deteriorates due to invalid TA and outdated spatial filters
Solution Approach 1:
The network device pre-configures the UE with reference signal configurations including TA and spatial filter parameters before the UE transitions to idle or inactive mode. This preliminary configuration enables the UE to maintain positioning capability without frequent wake-ups, resolving the contradiction between power saving and positioning accuracy
Solution Approach 2:
The network device receives feedback from the UE about its mobility state and directionality changes. Based on this feedback, the network dynamically updates the TA and spatial filter configurations, ensuring positioning accuracy is maintained while allowing the UE to remain in low-power mode
2Measurement precision
If UE uses pre-configured TA and spatial filters in idle mode, then positioning can be maintained, but interference increases due to outdated parameters
Solution Approach 1:
The system transitions from static pre-configured parameters to dynamic parameter updates. The network device monitors UE mobility and directionality, then dynamically adjusts TA and spatial filter configurations to match current UE state, eliminating interference caused by outdated parameters while maintaining positioning accuracy
Solution Approach 2:
The invention changes the parameters (TA and spatial filters) based on detected UE mobility and directionality. By adapting these parameters to the current state rather than using fixed pre-configured values, the system maintains accurate positioning while preventing interference from outdated parameter usage
Data Source
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AI summary
A user equipment (UE) transmits reference signals for positioning while in Idle or Inactive state. While in a connected state, the UE is preconfigured with Sounding Reference Signal (SRS) resource configuration including at least one of timing adjustment (TA) and an uplink (UL) transmission spatial filter. The UE transmits positioning SRS while in Idle or Inactive mode based on the preconfiguration. The TA and UL transmission spatial filter may be updated by a serving base station using control signals or a paging message received by the UE while in in Idle or Inactive mode. The validity of the TA and UL transmission spatial filter may be monitored using expiration timers or a relative position change threshold. The reference signals transmitted may be based on a UE may Physical Random Access Channel (PRACH), which is insensitive to TA changes. A long sequence PRACH may be used for improved positioning accuracy.