5G Unlicensed SSB Transmission With PBCH Position Indication

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Solution Overview

Problem

There is a lack of effective solutions for transmitting synchronization signal blocks (SSBs) in 5G unlicensed spectrums due to the need to follow the Listen Before Talk (LBT) principle, which may prevent fixed transmission positions, necessitating alternative offset positions and effective indication of these positions to user equipment (UE).

Innovation Solution

The method involves determining actual offset transmission positions for SSBs and transmitting actual sending position indication information through a physical broadcast channel block (PBCH), using various bit configurations to notify UE of the alternative positions, including slot block sequence numbers or sequence numbers of SSBs and their positions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If SSB transmission follows fixed position configuration, then transmission reliability is improved, but transmission opportunities are limited due to LBT principle constraints

Engineering Contradiction:
Improvetransmission reliabilityVSAvoidtransmission opportunities
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent applies dynamics by transitioning from fixed SSB transmission positions to dynamic alternative offset positions. The base station determines actual transmission positions from multiple alternative positions based on LBT results, allowing the system to adapt transmission timing dynamically. This resolves the contradiction by maintaining reliability through structured position selection while increasing productivity through multiple possible transmission opportunities.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the transmission position parameter from a fixed value to a selectable set of alternative offset positions. By configuring multiple alternative positions and dynamically selecting among them based on channel availability, the system improves both reliability (through consistent transmission) and productivity (through increased transmission opportunities when channel is available).

Inventive Principle:
Principle #35Parameter changes

2Productivity

If alternative offset transmission positions are used, then transmission opportunities are increased, but UE synchronization complexity increases

Engineering Contradiction:
Improvetransmission opportunitiesVSAvoidUE synchronization complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent introduces an intermediary mechanism (PBCH carrying indication information) that mediates between the base station's transmission position selection and the UE's synchronization process. The indication information acts as a bridge, conveying the actual transmission position to the UE without requiring complex blind detection, thus increasing transmission opportunities while managing UE complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system implements feedback by transmitting indication information about the actual offset position to the UE through PBCH. This feedback mechanism allows the UE to accurately determine the transmission position without complex synchronization procedures, resolving the contradiction between increased transmission opportunities and reduced UE complexity.

Inventive Principle:
Principle #23Feedback

3Measurement precision

If indication information is transmitted through PBCH, then UE can accurately determine transmission position, but information bit requirements increase

Engineering Contradiction:
Improveposition indication accuracyVSAvoidinformation bits
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent segments the position indication into two parts: pre-configured alternative offset positions and actual position selection indication. This segmentation allows accurate position indication while reducing information bits, as the UE only needs to receive the specific selection among pre-known alternatives rather than the complete position information.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies preliminary action by pre-configuring alternative offset positions before actual transmission. This allows the indication information to reference pre-established positions, reducing the number of bits needed while maintaining accurate position indication to the UE.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3855825B1Method and device for transmitting synchronization indication information
Publication Date: 2025.10.29 BEIJING XIAOMI MOBILE SOFTWARE CO LTD
  • EP3855825B1 patent drawingFigure 1~4
  • EP3855825B1 patent drawingFigure 5~8
  • EP3855825B1 patent drawingFigure 9~10

AI summary

The present invention relates to a method and a device for transmitting synchronization indication information. Said method comprises: determining, from alternative offset transmission positions, an actual offset transmission position of a synchronous broadcast block to be transmitted; generating actual sending position indication information according to the actual offset transmission position; and transmitting the synchronous broadcast block at the actual offset transmission position, and transmitting the actual sending position indication information by means of a physical broadcast channel (PBCH).