PHY Layer Procedure Adjustment for Satellite Switching Interruptions

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Solution Overview

Problem

Non-terrestrial communication networks, such as satellite networks, face challenges with communication interruptions due to satellite movement, leading to switching problems like RRC connection loss, excessive random access attempts, and resource wastage during transitions between satellite gateways or service links.

Innovation Solution

Implementing methods to adjust PHY layer procedures, including access barring, time/frequency resynchronization, and uplink power control, to mitigate switching issues during transitions in non-terrestrial networks, such as configuring transmission gaps and recalibrating uplink power based on new coupling loss estimates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If satellite movement and gateway switching are implemented to provide continuous coverage, then network coverage and service continuity are improved, but communication interruptions and switching problems occur

Engineering Contradiction:

Improvenetwork coverage areaVSAvoidcommunication continuity

Core Design Contradiction:

Area of stationary objectVSReliability

Solution Approach 1:

The network node determines the transition period in advance before the actual satellite gateway switching occurs. By predicting when communication interruptions will happen based on satellite movement trajectories, the system can prepare mitigation strategies proactively, such as pre-configuring handover parameters or warning wireless devices to pause transmissions, thereby reducing the impact of switching problems while maintaining continuous coverage

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent introduces access barring mechanisms and transmission gap configurations that act as cushioning measures during transition periods. These mechanisms temporarily reduce network access or pause transmissions before actual switching occurs, preventing excessive random access attempts and RRC connection losses that would otherwise occur during satellite gateway transitions, thus cushioning the blow to communication reliability

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Reliability

If PHY layer procedures are adjusted to mitigate switching problems, then switching reliability is improved, but transmission gaps and access barring increase latency

Engineering Contradiction:

Improveswitching reliabilityVSAvoidsignaling latency

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent dynamically adjusts PHY layer parameters such as transmission gap duration and access barring factors based on the specific transition period characteristics and network conditions. Rather than applying fixed mitigation measures, the system adapts the level of access restriction and transmission pausing to match the actual switching requirements, optimizing the balance between switching reliability and latency for each transition event

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes PHY layer parameters temporarily during transition periods and then restores them afterward. By confining the parameter adjustments (such as increasing access barring factors or introducing transmission gaps) to only the necessary transition window, the patent minimizes the overall time loss while ensuring switching reliability is maintained during the critical switching moment

Inventive Principle:

Principle #35Parameter changes

3Reliability

If random access attempts are allowed during transition periods, then connection recovery is improved, but resource wastage and network overload increase

Engineering Contradiction:

Improveconnection recoveryVSAvoidnetwork resource consumption

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent applies access barring as a preliminary anti-action to prevent excessive random access attempts during transition periods. By restricting access before the transition occurs or during the transition window, the system prevents the surge of failed access attempts that would waste network resources and energy, while still allowing connection recovery to proceed in an controlled manner after the transition completes

Inventive Principle:

Principle #9Preliminary anti-action

Data Source

PatentUS11770182B2Adapting PHY layer procedures for a moving RAN in non-terrestrial networks

Publication Date: 2023.09.26 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

A wireless device is operable to communicate with a network node of a communications network via a non-terrestrial communication path that includes satellites and satellite gateways. The wireless device determines that communication between the wireless device and the network node will experience a communication interrupting transition during a transition period in which the non-terrestrial communication path between the wireless device and the network node will be interrupted. The wireless device adjusts a PHY layer procedure of the wireless device to mitigate switching problems with one of the of satellites during and/or after the interruption.