PBCH Polar Coding Joint Encoding for Latency Reduction

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Solution Overview

Problem

Current wireless communication systems face challenges in efficiently encoding and decoding broadcast channel information, particularly in scenarios where blind decoding introduces latency and energy consumption, especially with increasing numbers of scrambling codes and beam sweeping techniques.

Innovation Solution

The proposed solution involves jointly encoding physical broadcast channel (PBCH) payloads with synchronization signal block indices using polar coding, allowing for soft-combining of transmissions across multiple non-continuous synchronization signal blocks to improve decoding performance and reduce latency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If blind decoding is used to determine cell acquisition information, then the UE can determine relevant information about the base station, but latency and energy consumption increase significantly

Engineering Contradiction:
Improvecell acquisition information determinationVSAvoidlatency
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by pre-configuring the UE with a set of candidate scrambling codes and master information block formats before the actual decoding process. The UE is also provided with timing information about when PBCH transmissions occur, allowing it to prepare decoding parameters in advance and systematically test only the most likely candidates rather than blindly decoding all possibilities, thereby reducing latency while maintaining reliable cell acquisition.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback mechanisms where the UE receives timing information about PBCH transmissions and uses this feedback to adjust its decoding strategy. The system provides feedback about which scrambling codes are most likely based on detected patterns, allowing the UE to refine its decoding attempts and reduce the search space, thereby decreasing latency while ensuring reliable information acquisition.

Inventive Principle:
Principle #23Feedback

2Reliability

If blind decoding is used to determine cell acquisition information, then the UE can determine relevant information about the base station, but energy consumption increases significantly

Engineering Contradiction:
Improvecell acquisition information determinationVSAvoidenergy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies preliminary action by pre-configuring the UE with a set of candidate scrambling codes and master information block formats before the actual decoding process. The UE is also provided with timing information about when PBCH transmissions occur, allowing it to prepare decoding parameters in advance and systematically test only the most likely candidates rather than blindly decoding all possibilities, thereby reducing latency while maintaining reliable cell acquisition.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes the parameters of the decoding process by introducing structured search criteria based on timing information and detected patterns. Instead of testing all possible scrambling codes equally, the system adjusts the search parameters to prioritize likely candidates based on temporal patterns and signal characteristics, reducing the total number of decoding operations and thus energy consumption while maintaining reliable cell acquisition.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the number of scrambling codes is increased to mitigate interference and convey timing information, then interference mitigation improves, but decoding complexity increases

Engineering Contradiction:
Improveinterference mitigationVSAvoiddecoding complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies local quality by treating different scrambling codes and timing intervals differently based on their local characteristics and reliability. The system identifies which scrambling codes are most likely to be used based on detected patterns and timing information, then focuses decoding resources on those specific local regions rather than uniformly processing all possible codes, thereby maintaining interference mitigation while reducing overall decoding complexity.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the parameters of the decoding process by introducing structured search criteria based on timing information and detected patterns. Instead of testing all possible scrambling codes equally, the system adjusts the search parameters to prioritize likely candidates based on temporal patterns and signal characteristics, reducing the total number of decoding operations and thus energy consumption while maintaining reliable cell acquisition.

Inventive Principle:
Principle #35Parameter changes

4Reliability

If beam sweeping techniques are used to transmit synchronization signals, then signal coverage improves, but the number of transmissions to combine increases

Engineering Contradiction:
Improvesignal coverageVSAvoidsoft-combining complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies merging by combining multiple PBCH transmissions from different beam sweeping intervals into a single unified decoding process. The system collects soft bits from multiple transmissions and integrates them using soft-combining techniques, treating all beams as part of a single logical channel. This merging approach maintains the signal coverage benefits of beam sweeping while managing complexity by processing multiple beams simultaneously rather than sequentially.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3574595B1Broadcast channel encoding and decoding
Publication Date: 2024.02.21 QUALCOMM INC
  • EP3574595B1 patent drawingFigure 1
  • EP3574595B1 patent drawingFigure 2
  • EP3574595B1 patent drawingFigure 3

AI summary

Methods, systems, and devices for wireless communication are described. In order to exchange data over a given wireless communication network, a wireless device may first perform a cell acquisition procedure (e.g., to determine cell-specific information such as timing and frequency offsets, bandwidth, control channel formatting, etc. ). In some systems, aspects of the timing information may be conveyed with scrambling codes applied to a master information block (MIB). Physical broadcast channel (PBCH) payloads, including MIB transmissions, may be jointly encoded with synchronization signal indices. Bursts of MIB transmissions may thus be decoded without blind decoding while maintaining error protection and low latency that may be necessary to obtain critical system information within the MIB.