NTN Random Access Using Early SIB Indication to Cut Delay

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Solution Overview

Problem

In non-terrestrial networks (NTNs), the large coverage range and limited beam power of satellite beams result in increased random access delay due to the need to receive SIB19 after at least one beam revisit period, leading to low random access efficiency.

Innovation Solution

A method and apparatus that utilize transmission indication information to enable terminals to receive an additional system information block (SIB) and perform random access based on both the additional SIB and SIB1, allowing for early reception and reducing the need to wait for the next beam revisit period.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If terminals wait for the next beam revisit period to receive SIB19, then the beam coverage and power constraints are satisfied, but the random access delay increases

Engineering Contradiction:
Improvebeam coverage satisfactionVSAvoidrandom access delay
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system information is segmented into multiple parts: SIB1 containing basic access parameters, and additional SIBs (such as SIB19) containing NTN-specific parameters. This segmentation allows terminals to perform random access using SIB1 immediately while obtaining complete NTN parameters from additional SIBs, thereby reducing access delay while maintaining beam coverage reliability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The network pre-configures multiple PDCCH monitoring occasions and provides transmission indication information in advance. Terminals monitor for transmission indication information that triggers additional SIB reception, allowing them to proactively prepare for random access without waiting for the complete beam revisit period, thus reducing delay while ensuring reliable parameter reception.

Inventive Principle:
Principle #10Preliminary action

2Productivity

If terminals receive additional SIB and perform random access earlier, then random access efficiency improves, but the complexity of system information management increases

Engineering Contradiction:
Improverandom access efficiencyVSAvoidsystem information management complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The network provides transmission indication information as feedback to terminals, indicating when additional SIBs will be transmitted. This feedback mechanism allows terminals to efficiently manage system information reception by monitoring specific indicators rather than continuously receiving all SIBs, improving access efficiency while maintaining manageable system complexity through structured information delivery.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system dynamically adapts information transmission based on terminal needs and network conditions. Additional SIBs are transmitted only when indicated by transmission indication information, allowing the system to flexibly provide NTN parameters when needed for random access while avoiding unnecessary transmissions that would increase management complexity.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4701317A1Random access method and apparatus
Publication Date: 2026.02.25 DATANG MOBILE COMM EQUIP CO LTD
  • EP4701317A1 patent drawingFigure 1~2
  • EP4701317A1 patent drawingFigure 3
  • EP4701317A1 patent drawingFigure 4~5

AI summary

Embodiments of the present disclosure provide a random access method and apparatus. The method comprises: receiving sending indication information of a new system information block (SIB), wherein the sending indication information indicates whether a network device sends the new SIB; and receiving, on the basis of the sending indication information, the new SIB sent by the network device, and performing random access on the basis of the new SIB and a SIB1.