NR Broadcast Channel Scrambling for Time Index Verification

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Solution Overview

Problem

In 5G NR wireless communication systems, the lack of error detection for the NR-TSS in synchronization signal blocks leads to delays and incorrect initial access due to potential errors in time index detection, causing inefficiencies in system information reception and random access procedures.

Innovation Solution

Implementing scrambling of system information in NR-PBCH using a pseudo-random sequence generated based on the time index provided by NR-TSS, allowing for early verification of detection accuracy and reducing delays by enabling CRC checks on scrambled bits or symbols.

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 because multiple NR-PSS transmissions are required

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 time index information in the NR-TSS before the actual data transmission in NR-PBCH. This allows the UE to know in advance which SS block is being transmitted, enabling faster processing and reducing the overall synchronization delay while maintaining beam sweeping coverage

Inventive Principle:
Principle #10Preliminary action

2Productivity

If NR-TSS is transmitted without error-detection code to reduce overhead, then transmission efficiency is improved, but detection reliability deteriorates due to potential errors in time index detection

Engineering Contradiction:
Improvetransmission efficiencyVSAvoiddetection reliability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent uses the CRC attached to NR-PBCH as an intermediary error detection mechanism. By scrambling the CRC with the time index, the system can indirectly verify the accuracy of time index detection without adding separate error detection to NR-TSS, thus maintaining transmission efficiency while improving detection reliability

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If scrambling is applied to system information using time index to enable early verification, then detection accuracy is improved, but processing complexity increases

Engineering Contradiction:
Improvedetection accuracyVSAvoidprocessing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges the error detection function with the existing CRC mechanism of NR-PBCH. By scrambling the CRC with the time index rather than adding separate verification mechanisms, the system improves detection accuracy while minimizing additional processing complexity by reusing existing structures

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3749021B1NR broadcast channel transmission
Publication Date: 2022.05.04 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3749021B1 patent drawingFigure 1~2a
  • EP3749021B1 patent drawingFigure 2b
  • EP3749021B1 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.