Additional CSI-RS and TRS for Non-Connected UE Power Saving

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Solution Overview

Problem

The infrequent transmission of reference signals in NR networks, such as SSB, poses challenges for UEs in RRC_IDLE or RRC_INACTIVE states, leading to increased energy consumption and inefficiencies.

Innovation Solution

UEs and network nodes implement methods for selectively receiving and transmitting configured reference signals based on availability and energy consumption considerations, using periodic channel state information RS (CSI-RS) or tracking RS (TRS) during designated occasions, and maintaining low-power modes when unnecessary.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If reference signals are transmitted frequently to ensure reliable communication for UEs in non-connected states, then communication reliability is improved, but energy consumption of UEs increases

Engineering Contradiction:

Improvecommunication reliabilityVSAvoidenergy consumption of UE

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies dynamics by making the reference signal transmission adaptive rather than static. The network dynamically determines whether to transmit connected-state reference signals during non-connected state based on UE behavior patterns, channel conditions, and service requirements. This allows the system to optimize between reliability and energy consumption by adjusting transmission frequency in real-time rather than using fixed periodic transmission

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the transmission parameter (frequency/periodicity) of reference signals based on UE state and requirements. By modifying the transmission parameters adaptively - transmitting only when necessary for maintaining synchronization or enabling efficient connected transitions - the system resolves the contradiction between ensuring communication reliability and minimizing UE energy consumption

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If UEs continuously monitor reference signals to maintain synchronization in non-connected states, then synchronization accuracy is improved, but operational efficiency deteriorates

Engineering Contradiction:

Improvesynchronization accuracyVSAvoidoperational efficiency

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The patent implements periodic action by having UEs monitor reference signals only at specific intervals or triggered events rather than continuously. The monitoring occurs periodically or on-demand based on whether connected-state reference signals are transmitted, allowing UEs to maintain adequate synchronization accuracy while significantly improving operational efficiency by reducing continuous monitoring overhead

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The patent applies partial action by having UEs perform synchronization monitoring only to the extent necessary - not continuously but at sufficient intervals to maintain adequate synchronization for efficient connected transitions. This partial monitoring approach achieves the minimum required synchronization accuracy while maximizing operational efficiency

Inventive Principle:

Principle #16Partial or excessive action

3Reliability

If UEs receive non-connected state reference signals (SSB) to maintain basic functionality, then basic communication capability is maintained, but energy consumption increases compared to lower power modes

Engineering Contradiction:

Improvebasic communication capabilityVSAvoidenergy loss

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent extracts the essential function of reference signal transmission by having the network transmit connected-state reference signals that can serve dual purposes - maintaining basic communication capability for non-connected UEs while enabling more efficient connected transitions. This extraction of the core synchronization and channel estimation function into connected-state signals eliminates the need for separate non-connected state reference signal transmissions, reducing energy loss

Inventive Principle:

Principle #2Taking out (Extraction)

Data Source

PatentUS20250293839A1Additional Reference Signals for UEs in Non-connected States

Publication Date: 2025.09.18 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

Embodiments include methods, performed by a user equipment (UE), for receiving reference signals (RS) in a wireless network. Such methods include receiving, from a network node in the wireless network, a configuration for connected-state RS transmitted by the network node. In some embodiments, the connected-state RS can be periodic channel state information RS (CSI-RS) or periodic tracking RS (TRS). Such methods include, while the UE is in a non-connected state and based on the received configuration, determining that the connected-state RS are available during one or more first occasions. Such methods include, while the UE is in the non-connected state, selectively receiving the connected-state RS during the first occasions. Other embodiments include complementary methods performed by a network node, as well as UEs and network nodes configured to perform such methods.