5G NR SI Request Backup Resources for Collision Avoidance

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Solution Overview

Problem

The challenge in 5G NR systems is the failure of on-demand system information delivery due to collisions and resource scarcity in Msg1 based SI requests, leading to inefficient retransmission attempts and potential network congestion.

Innovation Solution

Implementing backup resources, such as reserved preambles and PRACH time-frequency blocks, to transmit on-demand system information requests, which are activated only when collisions are detected, optimizing resource utilization and minimizing retransmissions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If Msg1 based SI request method is used, then SI request can be initiated by UE, but collision between multiple UEs causes delivery failure

Engineering Contradiction:
ImproveUE initiated SI request capabilityVSAvoidSI delivery success rate
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The network pre-configures multiple SI request resources (different preambles, time-frequency slots) for different SI messages. When a UE needs to request SI, it can select from these pre-configured resources, reducing the likelihood of collision with other UEs requesting the same SI simultaneously.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The SI request resources are segmented into multiple distinct options (different preambles, different time-frequency resources). Instead of a single shared resource that causes collisions, multiple segmented resources allow simultaneous requests from multiple UEs without interference.

Inventive Principle:
Principle #1Segmentation

2Reliability

If retransmission attempts are made after SI request failure, then SI can be delivered, but network congestion increases

Engineering Contradiction:
ImproveSI delivery success rateVSAvoidNetwork efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The system dynamically adjusts the SI request approach based on whether the UE is in coverage. In-coverage UEs use the standard Msg1 request with retransmission, while out-of-coverage UEs use alternative methods (reading MSI/SI from other cells or skipping the request). This dynamic adaptation prevents unnecessary retransmissions that would congest the network.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

Out-of-coverage UEs can obtain SI by reading it from other cells that are in coverage, rather than attempting to request and retransmit. This copying approach from neighboring cells eliminates the need for repeated failed requests that would congest the network.

Inventive Principle:
Principle #26Copying

3Device complexity

If all UEs use the same SI request resources, then resource allocation is simple, but collision probability increases

Engineering Contradiction:
ImproveResource allocation complexityVSAvoidSI request success rate
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

Different SI request resources (preambles, time-frequency slots) are assigned to different SI messages based on local characteristics. Each SI message has its dedicated set of resources, and UEs request specific SI using the resources associated with that SI, reducing collisions while maintaining manageable complexity.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3692760B1Base stations and user equipments configured to handle on-demand system information in 5g nr
Publication Date: 2026.04.15 SONY GROUP CORP
  • EP3692760B1 patent drawingFigure 1~2
  • EP3692760B1 patent drawingFigure 3~4
  • EP3692760B1 patent drawingFigure 5~6

AI summary

The present disclosure provides a user equipment for a mobile telecommunications system, which includes circuitry configured to communicate with a new radio base station. The circuitry is further configured to transmit an on-demand system information request to the new radio base station, wherein the on-demand system information request is transmitted based on a backup resource.