Two-Stage PDCCH Scrambling for Early Termination

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Solution Overview

Problem

Existing wireless communication systems face inefficiencies in decoding Physical Downlink Control Channels (PDCCH) due to the lack of effective early termination mechanisms, leading to unnecessary processing of transmissions not intended for the wireless transmit/receive unit (WTRU).

Innovation Solution

Implementing a two-stage scrambling process using a Gold sequence and a cell radio network temporary ID (C-RNTI) for PDCCH decoding, allowing early termination based on successful descrambling and ABA polar decoding to identify intended transmissions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If single-stage decoding is used for PDCCH transmissions, then decoding process is simple, but early termination cannot be performed leading to unnecessary processing of non-intended transmissions

Engineering Contradiction:
Improvedecoding efficiencyVSAvoiddecoding process complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The decoding process is divided into two distinct stages: first stage uses a first scrambling sequence (e.g., based on WTRU ID) for initial descrambling and early termination check, while the second stage uses a second scrambling sequence (e.g., C-RNTI) for final decoding. This segmentation allows the system to terminate decoding early for non-intended transmissions without requiring complex multi-hypothesis testing, thus improving decoding efficiency while maintaining manageable complexity through structured process division.

Inventive Principle:
Principle #1Segmentation

2Loss of time

If early termination mechanism is implemented, then processing of non-intended transmissions is reduced, but additional scrambling sequences and stages are required increasing system complexity

Engineering Contradiction:
Improveprocessing time for non-intended transmissionsVSAvoidscrambling sequence management
Core Design Contradiction:
Loss of timeVSDevice complexity

Solution Approach 1:

The first scrambling sequence is applied preliminarily before the main decoding process to enable early identification of non-intended transmissions. By performing this preliminary descrambling and check stage first, the system can discard non-intended transmissions before committing resources to full decoding, thus reducing processing time for non-intended transmissions while managing complexity through a structured two-stage approach where each stage has a specific purpose.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3639423B1Two-stage scrambling for polar coded pdcch transmission
Publication Date: 2025.09.10 INTERDIGITAL PATENT HOLDINGS INC
  • EP3639423B1 patent drawingFigure 1A
  • EP3639423B1 patent drawingFigure 1B
  • EP3639423B1 patent drawingFigure 1C

AI summary

A wireless transmit receive unit (WTRU) may receive a Physical Downlink Control Channel (PDCCH) transmission and perform early termination on the PDCCH transmission. Transmissions that are not intended for the WTRU may be terminated. The WTRU may perform a first decoding of the PDCCH transmission based on a first scrambling sequence. The first scrambling sequence may be generated using a Gold sequence, which may be initialized based on a WTRU identifier. If the first decoding is not successful, the WTRU may determine that the PDCCH transmission is not intended for the WTRU. The WTRU may perform an assistance bit aided (ABA) polar decoding of the PDCCH transmission based on a second scrambling sequence (e.g., a cell radio network temporary ID (C-RNTI)). The WTRU may perform a CRC on the output of the ABA polar decoding to obtain downlink control information (DCI).