PDCCH Candidate Dropping via Round-Robin Search Space Switching

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Solution Overview

Problem

The existing wireless communication systems, particularly in LTE/LTE-A, face challenges in efficiently and accurately transmitting and receiving physical downlink control channel (PDCCH) signals due to high channel estimation complexity, leading to increased operation complexity and potential delays in decoding operations.

Innovation Solution

The proposed method involves configuring user equipment (UE) to drop PDCCH candidates on an individual basis rather than a search space set basis, and implementing priority rules for CORESET and search space set prioritization to manage channel estimation complexity, thereby reducing the number of blind-decodings and channel estimations within a specific time unit.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the UE monitors all PDCCH candidates in a search space set, then the reliability of control channel reception is improved, but the channel estimation complexity and operation complexity increase significantly

Engineering Contradiction:
Improvecontrol channel reception reliabilityVSAvoidchannel estimation complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the search space set into multiple groups, where each group contains a subset of PDCCH candidates. The UE is configured to monitor only one group per search space set, dividing the total monitoring burden into manageable segments. This segmentation reduces channel estimation complexity while maintaining reliable control channel reception through the grouped candidate structure.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If the UE monitors all PDCCH candidates, then the scheduling flexibility of the network is improved, but the processing time and operation complexity increase

Engineering Contradiction:
Improvescheduling flexibilityVSAvoiddecoding operation time
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by pre-configuring multiple groups of PDCCH candidates within each search space set before transmission. The UE is预先 provided with the group configurations, allowing it to efficiently select and monitor only the relevant group without performing exhaustive monitoring. This preliminary structuring enables the network to maintain scheduling flexibility while reducing the UE's real-time processing time and operation complexity.

Inventive Principle:
Principle #10Preliminary action

3Device complexity

If the UE drops PDCCH candidates on a search space set basis, then the operation complexity is reduced, but the scheduling flexibility and performance utilization are limited

Engineering Contradiction:
Improveoperation complexityVSAvoidscheduling flexibility
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent implements local quality by allowing different treatment of different groups within a search space set. Instead of uniformly dropping all candidates or monitoring all candidates across the entire search space set, the UE monitors one specifically configured group while others are dropped. This localized approach enables fine-grained control over which candidates are monitored, reducing operation complexity while preserving scheduling flexibility through the group-based configuration.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3742634B1Method for monitoring pdcch candidates and control channel elements and determining pdcch candidates to be dropped and apparatus therefor
Publication Date: 2024.10.09 LG ELECTRONICS INC
  • EP3742634B1 patent drawingFigure 1
  • EP3742634B1 patent drawingFigure 2
  • EP3742634B1 patent drawingFigure 3

AI summary

A method for receiving a PDCCH signal by a terminal in a wireless communication system according to one embodiment of the present invention may comprise the steps of: determining the number of CCEs for channel estimation and the number of times of blind-decoding related to multiple search space sets that the terminal needs to monitor during one slot; when the determined number of times of the blind-decoding exceeds a blind-decoding limit or the determined number of the CCEs exceeds a channel estimation limit, dropping at least one PDCCH candidate among PDCCH candidates included in the multiple search space sets; and attempting to detect a PDCCH signal on the basis of remaining PDCCH candidates which have not been dropped among the PDCCH candidates, wherein, in the dropping of the at least one PDCCH candidate, the terminal switches between the multiple search space sets in a round-robin scheme while dropping the at least one PDCCH candidate until both the blind-decoding limit and the channel estimation limit are reached.