Idle-State Uplink SRS Positioning for 5G NR UE Location
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Solution Overview
Problem
Current location technologies for 5G NR terminals in idle or inactive states lack support for uplink signal-based location methods, leading to poor accuracy and increased power consumption due to the need for continuous network access and measurement of multiple cells.
Innovation Solution
A method and system that enables uplink signal location by configuring SRS resources for terminals in idle or inactive states through RRC connection release messages, allowing them to transmit SRS for location without active network connection, with configuration details including valid duration, positioning area, and transmission cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If downlink signal location method is used for idle/inactive terminals, then location can be supported, but measurement time is long and location accuracy is poor
Solution Approach 1:
The patent inverts the traditional downlink signal location approach by using uplink signals for location. Instead of the network measuring downlink signals from the terminal, the terminal transmits SRS (Sounding Reference Signal) in uplink, and the network measures these uplink signals to determine location. This inversion enables location in idle/inactive states without requiring continuous network access or lengthy measurements of multiple cells.
Solution Approach 2:
The patent applies preliminary action by configuring SRS resources in advance through RRC connection release messages before the terminal enters idle or inactive state. The SRS resource configuration includes parameters such as time-frequency resources, cyclic shifts, and validity durations, allowing the terminal to immediately transmit location signals when needed without requiring network reconnection or extended measurement procedures.
2Measurement precision
If downlink signal location method is used, then location can be obtained, but terminal power consumption increases due to continuous network access
Solution Approach 1:
The patent changes the direction of signal transmission from downlink to uplink. The terminal transmits SRS signals in uplink while in idle or inactive state, and the network measures these signals for location determination. This approach eliminates the need for continuous downlink signal reception and network access, significantly reducing terminal power consumption while maintaining location capability.
Solution Approach 2:
The patent implements periodic action through configured SRS transmission cycles and validity durations. Instead of continuous transmission, the terminal transmits SRS signals periodically according to pre-configured parameters (e.g., every 10ms, 20ms, or 40ms) only when needed for location updates. This periodic transmission pattern reduces power consumption compared to continuous network access while ensuring location information is refreshed at appropriate intervals.
3Measurement precision
If uplink signal location is enabled for idle/inactive terminals, then location accuracy improves, but device complexity increases
Solution Approach 1:
The patent applies universality by making the SRS resource configuration mechanism serve multiple functions. The same RRC connection release message structure is used for both connection management and SRS resource configuration. The SRS resources are configured with flexible parameters that can adapt to different location scenarios and terminal capabilities, allowing a single configuration mechanism to handle various idle/inactive state location requirements without requiring separate dedicated configuration procedures.
Data Source
AI summary
An uplink signal location method, a communication base station, a measurement base station, and a UE. The uplink signal location method including: the communication base station determines that the UE satisfies the condition of releasing an RRC connection, the UE has a location requirement, and an LMF entity indicates the UE to use the uplink signal location method; transmits an RRC connection release message to the UE, and the RRC connection release message includes an SRS resource that is configured for the UE and used for location when the UE is in an idle state or an inactive state; the UE receives the RRC connection release message, releases the RRC connection and enters the idle state or inactive state, and uses the SRS resource to transmit an SRS.