NR Broadcast Channel Scrambling for SS Block Time Index Verification

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Solution Overview

Problem

In the context of 5G NR wireless communication, the detection of the NR-TSS for determining the boundary of SS burst or SS burst set is prone to errors without a CRC, leading to incorrect system information delivery and delays in the initial access procedure.

Innovation Solution

Scrambling the system information of NR-PBCH with a pseudo-random sequence generated based on the time index provided by NR-TSS, allowing early verification of detection accuracy through CRC checks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If beam sweeping is used to transmit NR-PSS in different beams at different time instants, then coverage is improved, but synchronization delay increases and frame start detection becomes ambiguous

Engineering Contradiction:
Improvecoverage areaVSAvoidsynchronization delay
Core Design Contradiction:
Area of stationary objectVSLoss of time

Solution Approach 1:

The patent applies preliminary action by transmitting the NR-TSS (tertiary synchronization signal) before the actual frame start to provide advance timing information. This allows the UE to know the frame boundary in advance, eliminating the ambiguity caused by beam sweeping and enabling proper timing for receiving subsequent system information without increasing overall synchronization delay.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The NR-TSS acts as an intermediary signal between the NR-PSS (primary synchronization signal) and the frame data transmission. It mediates the timing relationship by providing a reference point that helps the UE determine the frame start position even when NR-PSS transmissions are spread across different beams and time instants.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Quantity of substance

If NR-TSS is transmitted without error detection, then overhead is reduced, but detection accuracy cannot be verified leading to incorrect initial access

Engineering Contradiction:
Improvesignal overheadVSAvoiddetection accuracy
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent implements feedback by using the CRC (Cyclic Redundancy Check) of the system information to verify the accuracy of the NR-TSS detection. The UE uses the detected time index from NR-TSS to determine when to expect system information, then verifies whether the received system information is correct by checking its CRC. This feedback mechanism allows error detection without adding direct overhead to the NR-TSS itself.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP4102794B1NR broadcast channel transmission
Publication Date: 2026.05.06 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP4102794B1 patent drawingFigure 1~2a
  • EP4102794B1 patent drawingFigure 2b
  • EP4102794B1 patent drawingFigure 2c

AI summary

The disclosure relates to a method performed by a wireless device, for receiving system information from a network node of a wireless communication system. The system information is received in a synchronization signal (SS) block of an SS burst set comprising at least one SS block. The system information is multiplexed with information providing a time index indicating which SS block of the SS burst set that is being received. The method comprises receiving (430) the system information which comprises descrambling the system information using a scrambling sequence generated (420) based on the time index. The method also comprises determining (440) whether the information providing the time index is accurate, based on an error-detection code related to the received system information. The disclosure also relates to corresponding network node method and apparatus.