CU-DU SRS Provisioning for RRC-Inactive Positioning Measurement

Solution Overview

Problem

The challenge lies in providing a sounding reference signal (SRS) configuration to a user equipment (UE) operating in the RRC_INACTIVE state for uplink and downlink data transmission, as existing methods do not clearly outline how a distributed base station configures SRS for the UE in this state.

Innovation Solution

A method implemented in a central unit (CU) of a distributed base station that transmits a CU-to-DU message requesting SRS resources, receives a DU-to-CU message with an SRS configuration, and sends a command to the UE to release the radio connection, including the SRS configuration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the UE operates in RRC_INACTIVE state without SRS configuration, then the UE can maintain power saving and reduced complexity, but the UE cannot perform accurate positioning and uplink data transmission

Engineering Contradiction:

Improvepositioning capabilityVSAvoidconfiguration complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The network performs preliminary action by pre-configuring SRS resources and parameters in the RRC_INACTIVE state before the UE needs to transmit uplink data or perform positioning. The SRS configuration is included in the RRC release message, allowing the UE to use pre-established configuration without requiring complex real-time setup procedures.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent introduces an intermediary mechanism where the network node (gNB) acts as a mediator between the core network and the UE. The network node manages the SRS configuration and activates it conditionally based on data availability, serving as an intermediary that coordinates between different network functions and the UE without requiring direct complex interactions.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If the UE transitions to RRC_CONNECTED state for data transmission, then reliable data communication is achieved, but latency increases and power consumption rises

Engineering Contradiction:

Improvedata transmission efficiencyVSAvoidstate transition latency

Core Design Contradiction:

ProductivityVSLoss of time

Solution Approach 1:

The network performs preliminary action by pre-configuring SRS resources and parameters in the RRC_INACTIVE state before the UE needs to transmit uplink data or perform positioning. The SRS configuration is included in the RRC release message, allowing the UE to use pre-established configuration without requiring complex real-time setup procedures.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent introduces an intermediary mechanism where the network node (gNB) acts as a mediator between the core network and the UE. The network node manages the SRS configuration and activates it conditionally based on data availability, serving as an intermediary that coordinates between different network functions and the UE without requiring direct complex interactions.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Ease of operation

If SRS configuration is provided in RRC release message, then uplink data transmission is enabled in RRC_INACTIVE state, but the message size increases

Engineering Contradiction:

Improvedata transmission capabilityVSAvoidmessage structure complexity

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The network performs preliminary action by pre-configuring SRS resources and parameters in the RRC_INACTIVE state before the UE needs to transmit uplink data or perform positioning. The SRS configuration is included in the RRC release message, allowing the UE to use pre-established configuration without requiring complex real-time setup procedures.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The SRS configuration mechanism serves multiple functions simultaneously: it enables uplink data transmission, supports positioning operations, and maintains network control over the UE's radio resources. By integrating SRS configuration into the existing RRC release message structure, the patent achieves multi-functionality without requiring separate dedicated signaling messages.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS20250330284A1Managing Positioning Measurement for an Inactive State

Publication Date: 2025.10.23 GOOGLE LLC

AI summary

A central unit (CU) of a distributed base station that further includes a distributed unit (DU) is configured to transmit, to the DU, a CU-to-DU message requesting sounding reference signals (SRS) resources for a UE; receives, from the DU and in response to the CU-to-DU message, a DU-to-CU message including an SRS configuration for the UE; and transmits, to the UE via the DU, a command to release the radio connection, the command including the SRS configuration.