Satellite Revisit Signaling for UE Power Saving in NTN Coverage Gaps

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Solution Overview

Problem

In non-terrestrial networks (NTNs), UEs experience discontinuous network coverage due to satellite movement, leading to wasted power and decreased battery life during futile cell search procedures between satellite handovers.

Innovation Solution

UEs receive an indication of satellite visit time from the NTN or terrestrial network, allowing them to enter idle, inactive, or power-saving states until the next satellite is positioned for communication, thereby conserving power and reducing unnecessary operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If UEs continuously perform cell search procedures between satellite handovers, then network coverage is maintained, but power consumption increases and battery life decreases

Engineering Contradiction:

Improvenetwork coverageVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The network provides UEs with advance information about upcoming satellite handovers and coverage availability. UEs use this preliminary information to determine when to wake up and perform cell search procedures, avoiding continuous monitoring and reducing power consumption while maintaining reliable network coverage.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Instead of continuous cell search procedures, UEs perform monitoring periodically based on network-provided satellite handover information. This periodic action maintains network coverage reliability while significantly reducing power consumption compared to continuous monitoring.

Inventive Principle:

Principle #19Periodic action

2Reliability

If UEs perform cell search procedures during discontinuous coverage periods, then network connectivity is maintained, but unnecessary power is wasted

Engineering Contradiction:

Improvenetwork connectivityVSAvoidpower wastage

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The network provides feedback to UEs about satellite positions, handover times, and coverage availability. UEs use this feedback information to intelligently determine when to wake up and perform cell search procedures, ensuring network connectivity is maintained only when necessary and avoiding power wastage during periods when satellites will not be available.

Inventive Principle:

Principle #23Feedback

3Loss of information

If UEs monitor for broadcast signals continuously, then network updates are received promptly, but battery life is reduced

Engineering Contradiction:

Improvenetwork updatesVSAvoidbattery life

Core Design Contradiction:

Loss of informationVSDuration of action of stationary object

Solution Approach 1:

The network provides UEs with preliminary information about satellite handovers and coverage periods in advance. UEs schedule their monitoring of broadcast signals to coincide with these predicted coverage periods, ensuring they receive network updates promptly while extending battery life by avoiding continuous monitoring.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS12526730B2Techniques for communicating satellite revisit time in a non-terrestrial network

Publication Date: 2026.01.13 QUALCOMM INC

AI summary

Methods, systems, and devices for wireless communications are described. A user equipment (UE) may be configured to receive control signaling indicating a satellite visit time associated with one or more satellites. The UE may be configured to operate in an idle state, an inactive state, or a power-saving state for a time interval which is based on the satellite visit time. The UE may then be configured to monitor for one or more broadcast signals associated with the one or more satellites, one or more network entities, or both, following an end of the time interval which is based on the satellite visit time.