NTN Random Access Channel Configuration by Cell Location

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Solution Overview

Problem

User equipment devices in non-terrestrial networks face challenges with random access procedures due to varying cell coverage times and locations, leading to disparities in access success probability, especially for devices near cell edges or with limited cell availability.

Innovation Solution

A network node configures multiple physical random access channel configurations based on user equipment's relative location within the cell, providing different access opportunities, preambles, and backoff timers to optimize access chances for devices with varying cell availability times.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single physical random access channel configuration is used for all user equipment in the cell, then the system is simple to manage, but user equipment near cell edges or with limited cell availability experience lower access success probability

Engineering Contradiction:
Improveaccess success probabilityVSAvoidrandom access channel configuration complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the cell into multiple zones based on relative location (e.g., center zone, edge zone) and assigns different physical random access channel configurations to each zone. This segmentation allows user equipment in different locations to use optimized configurations, improving access success probability for edge devices while maintaining manageable system complexity through automated zone-based assignment.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by providing location-specific random access channel configurations tailored to the characteristics of different cell zones. User equipment in edge zones receives configurations with parameters optimized for their specific conditions (e.g., different preamble formats, power levels, or timing advance values), while center zone equipment uses standard configurations, thereby improving overall reliability without uniformly increasing complexity across the entire cell.

Inventive Principle:
Principle #3Local quality

2Reliability

If multiple physical random access channel configurations are provided for different relative locations, then access success probability improves, but the complexity of configuration management increases

Engineering Contradiction:
Improveaccess success probabilityVSAvoidconfiguration management ease
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent implements self-service by enabling user equipment to autonomously determine its own relative location within the cell and select the appropriate physical random access channel configuration without manual intervention. The network node provides configuration sets and location thresholds, and the user equipment automatically compares its measured relative location against these thresholds to select the optimal configuration, thereby improving access success while simplifying network-side management.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent applies preliminary action by pre-configuring multiple physical random access channel configurations and their associated location thresholds in advance. The network node prepares these configuration sets before user equipment needs to access the network, and user equipment can immediately compare its current relative location against the pre-defined thresholds to select the appropriate configuration, eliminating the need for real-time complex decision-making or manual configuration adjustments.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If user equipment near cell edges is given more access opportunities, then their access success improves, but contention increases for resources

Engineering Contradiction:
Improveaccess success probabilityVSAvoidcontention
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent applies local quality by providing location-specific random access channel configurations that include location-appropriate parameters such as different preamble formats, power levels, and timing advance values. User equipment in edge zones receives configurations optimized for their specific conditions, which improves their access success probability without simply increasing the number of access opportunities for all devices, thereby avoiding excessive contention.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent implements parameter changes by adjusting key random access parameters (such as preamble format, transmission power, timing advance, and backoff values) based on the user equipment's relative location within the cell. These parameter adjustments are tailored to the specific needs of edge zone equipment, improving their access success while maintaining balanced resource utilization and preventing excessive contention that would result from uniformly increasing access opportunities across all zones.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4486044B1Method for equalizing access success across ntn cell
Publication Date: 2026.02.04 NOKIA TECHNOLOGIES OY
  • EP4486044B1 patent drawingFigure 1~2
  • EP4486044B1 patent drawingFigure 3
  • EP4486044B1 patent drawingFigure 4

AI summary

A method, apparatus, and computer program product are provided. In the context of a method, the method receives, from a network node, a message indicating a plurality of physical random access channel configurations and at least one relative location threshold. The message determines, based on comparing a relative location of the user equipment to the relative location threshold, a selected physical random access channel configuration out of the plurality of physical random access channel configurations. The method performs a random access procedure based on the selected physical random access channel configuration.