Inactive UE SRS Configuration for 5G NR Positioning Handover
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Solution Overview
Problem
In 5G NR uplink positioning, when user equipment (UE) transitions from an inactive state to another base station, the last serving base station cannot configure sounding reference signal (SRS) configuration information, leading to failure in positioning by the location management function (LMF) device.
Innovation Solution
A first access network device sends a retrieve UE context request to a source access network device to obtain reference information for configuring SRS for the UE in inactive state, determining and sending the SRS configuration information to the UE, enabling successful positioning by the LMF.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the LMF device requests the last serving base station to configure SRS configuration information for the UE in inactive state, then the positioning function can be maintained, but when the UE moves to a new base station, the last serving base station cannot configure SRS configuration information, causing positioning failure
Solution Approach 1:
The patent introduces a new intermediary entity (the new base station) that acts as a mediator between the LMF device and the UE. When the UE moves to a new base station, this new base station receives the SRS configuration request from the LMF device, retrieves the necessary context information, and configures the SRS for the UE. This intermediary approach resolves the contradiction by enabling the new base station to fulfill the positioning function that the last serving base station can no longer provide due to UE mobility.
2Use of energy by moving object
If the UE remains in inactive state for positioning, then energy consumption is reduced, but the positioning latency increases due to the need to retrieve context information from the last serving base station
Solution Approach 1:
The patent applies preliminary action by having the new base station proactively retrieve the UE context information (including SRS configuration parameters) from the last serving base station before the actual positioning measurement is needed. This advance preparation ensures that when the LMF device sends the SRS configuration request, the new base station can immediately configure and transmit the SRS to the UE without delay, thus maintaining low positioning latency while the UE remains in the energy-saving inactive state.
Data Source
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AI summary
Embodiments of this application disclose a communication method and a related apparatus, to position a terminal device by a positioning device. A first access network device sends a retrieve UE context request message to a source access network device. The first access network device receives a retrieve UE context response message from the source access network device. The retrieve UE context response message includes reference information used to configure a sounding reference signal SRS of a terminal device, and/or information used to indicate to configure an SRS for the terminal device. The terminal device is in inactive state. The first access network device determines SRS configuration information of the terminal device based on the reference information and/or the information used to indicate to configure the SRS for the terminal device. The first access network device sends the SRS configuration information to the terminal device.