Tracking Reference Signal Availability Signaling for UE Power Reduction

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Solution Overview

Problem

In 5G/NR wireless communication networks, user equipment (UE) operating in non-connected states face challenges due to the infrequent transmission of reference signals, leading to increased energy consumption and reduced battery life, as they must frequently wake up to receive less frequent synchronization signals, which are typically transmitted every 5-160 ms.

Innovation Solution

The implementation of a method where user equipment (UE) receives configuration information for tracking reference signals (TRS) from network nodes, specifying occasions of TRS transmission, and determines availability based on signaled information, allowing the UE to selectively receive TRS during designated times, reducing the need for continuous active listening and thus lowering energy consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by stationary object

If reference signals are transmitted infrequently to reduce network power consumption, then network energy efficiency is improved, but UE energy consumption increases due to frequent wake-ups for synchronization

Engineering Contradiction:

Improvenetwork power consumptionVSAvoidUE power consumption

Core Design Contradiction:

Use of energy by stationary objectVSUse of energy by moving object

Solution Approach 1:

The network transmits TRS signals in advance during connected state before the UE transitions to non-connected state. This preliminary action allows the UE to perform synchronization and AGC tuning ahead of time, so that when the UE later wakes up in non-connected state, it can rely on the previously established synchronization parameters rather than needing to frequently wake up and reacquire synchronization signals.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements periodic transmission of Tracking Reference Signals (TRS) during connected state, with configurable periodicity. This periodic action creates predictable synchronization opportunities that allow the UE to plan its wake-up schedule more efficiently, reducing the need for frequent unscheduled wake-ups to check for synchronization signals.

Inventive Principle:

Principle #19Periodic action

2Reliability

If UEs frequently wake up to receive synchronization signals, then synchronization accuracy is maintained, but battery life is reduced due to increased energy consumption

Engineering Contradiction:

Improvesynchronization accuracyVSAvoidbattery life

Core Design Contradiction:

ReliabilityVSDuration of action of moving object

Solution Approach 1:

Synchronization and AGC tuning are performed in advance during connected state when the UE is powered on, rather than repeatedly during non-connected state. This preliminary synchronization maintains accuracy while extending battery life by reducing the frequency and duration of wake-up events.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent enables continuous synchronization maintenance through the combination of periodic TRS transmission during connected state and the UE's ability to utilize these signals throughout the subsequent non-connected period. This creates a continuous useful action for synchronization without requiring the UE to continuously monitor for signals, thus preserving battery life while maintaining sync accuracy.

Inventive Principle:

Principle #20Continuity of useful action

3Reliability

If UEs monitor for reference signals continuously to maintain synchronization, then connection reliability is improved, but energy consumption increases

Engineering Contradiction:

Improveconnection reliabilityVSAvoidenergy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

Instead of continuous monitoring, the patent implements periodic TRS transmission with configurable intervals during connected state. The UE can then enter non-connected state with reduced monitoring activity, checking for signals only at predetermined intervals rather than continuously, which significantly reduces energy consumption while maintaining adequate connection reliability.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The network performs preliminary signal transmission and synchronization setup during connected state before the UE enters non-connected state. This allows the UE to reduce its monitoring activity during non-connected state while still maintaining reliable connection, as the preliminary synchronization information remains valid for an extended period.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS20240187988A1Network Node, User Equipment, and Methods Performed Therein for Communication of Availability Information for Reference Signals

Publication Date: 2024.06.06 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

Embodiments include methods, performed by a user equipment (UE), for receiving tracking reference signals, TRS, in a wireless network. An example method comprises receiving, from 5 the network node, system information including a configuration for tracking reference signals, the configuration specifying a plurality of occasions at which the network node may transmit tracking reference signals, where the system information further specifies at least a first window in which availability information for a tracking reference signal according to the configuration will be signaled. The example method further comprises receiving the availability information 0 during the at least a first window, and determining whether a tracking reference signal is available, based on the received availability information.