SSB-RMSI Integration in Unlicensed Spectrum to Eliminate LBT Gaps

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Solution Overview

Problem

In wireless communications systems operating in shared radio frequency spectrum bands, transmission gaps caused by listen-before-talk (LBT) procedures can lead to delays and inefficiencies in delivering synchronization signal blocks (SSBs) and remaining minimum system information (RMSI), as other devices may gain control of the transmission medium during these gaps.

Innovation Solution

Integrating SSB and RMSI transmissions within a single transmission opportunity (TxOP) using a single LBT, with continuous or back-to-back delivery, and configuring resource allocations to minimize gaps, and employing inverse quasi co-location for efficient signaling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If SSB and RMSI are transmitted separately with multiple LBT procedures, then transmission reliability may be improved through retransmission opportunities, but transmission gaps increase allowing other devices to gain control of the transmission medium

Engineering Contradiction:
Improvetransmission reliabilityVSAvoidtransmission gaps
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent merges SSB and RMSI transmissions into a single continuous transmission opportunity (TxOP), eliminating gaps between transmissions. By combining these transmissions and using a single LBT procedure, the system maintains reliability while preventing other devices from gaining control during transmission gaps.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent implements continuous transmission of SSB and RMSI within a single TxOP, ensuring no interruptions or gaps in the transmission sequence. This continuity prevents other wireless devices from performing LBT and gaining control of the medium, thereby resolving the contradiction between maintaining reliability and eliminating transmission gaps.

Inventive Principle:
Principle #20Continuity of useful action

2Adaptability or versatility

If multiple LBT procedures are performed for SSB and RMSI transmissions, then transmission opportunities are increased, but the likelihood of other devices gaining control of the transmission medium increases

Engineering Contradiction:
Improvetransmission opportunitiesVSAvoidcontrol of transmission medium
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent combines multiple transmission opportunities into a single extended TxOP that encompasses both SSB and RMSI transmissions. By performing a single LBT procedure at the beginning of this combined TxOP, the system maintains adaptability while ensuring continuous control of the transmission medium throughout the entire transmission sequence.

Inventive Principle:
Principle #5Merging (Combining)

3Adaptability or versatility

If SSB and RMSI are transmitted in separate transmission opportunities, then resource allocation flexibility is improved, but transmission gaps increase reducing efficiency

Engineering Contradiction:
Improveresource allocation flexibilityVSAvoidtransmission efficiency
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent merges SSB and RMSI into a single continuous TxOP, eliminating transmission gaps and improving overall transmission efficiency. Resource allocation flexibility is maintained through configurable parameters such as RMSI control resource set locations and downlink shared channel allocations within the unified transmission framework.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3837796B1Synchronization signal block and remaining minimum system information integration in unlicensed systems
Publication Date: 2026.03.18 QUALCOMM INC
  • EP3837796B1 patent drawingFigure 1
  • EP3837796B1 patent drawingFigure 2
  • EP3837796B1 patent drawingFigure 3

AI summary

Methods, systems, and devices for wireless communications are described. A base station and user equipment (UE) may implement techniques to integrate remaining minimum system information (RMSI) and synchronization signal block (SSB) delivery in a shared radio frequency spectrum band. For example, the base station may transmit SSBs and corresponding RMSI transmissions in a same transmission opportunity (TxOP) and configure resource allocations to reduce or eliminate transmission gaps. For example, the SSBs and the corresponding RMSI transmissions may be transmitted after a single, successful listen- before-talk (LBT) procedure. For each SSB, the associated RMSI control resources and RMSI shared channel resources may be nearby or continuous in time such that the SSB, control resource set, and the RMSI downlink shared channel signal are transmitted as a package.