Multicarrier PDCCH Search Space Distribution for Blind Decode Reduction

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Solution Overview

Problem

In LTE wireless communication systems, the current downlink control channel (PDCCH) transmission method requires users to decode multiple candidates, leading to scheduling restrictions and potential collisions due to overlapping search spaces, especially when multiple carriers are monitored.

Innovation Solution

The method involves distributing search spaces and aggregation levels across different carriers, and limiting the number of decoding candidates on each carrier to reduce the total number of blind decodes, allowing for orthogonal or non-orthogonal distribution, thereby minimizing scheduling restrictions and collisions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multiple carriers are monitored to increase data transmission capacity, then the data transmission capacity is improved, but the number of blind decodes required increases leading to scheduling restrictions and collisions

Engineering Contradiction:
Improvedata transmission capacityVSAvoidnumber of blind decodes
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent segments the search space across multiple carriers by distributing decoding candidates to different carriers based on aggregation levels. Specifically, it divides the control channel candidates into first candidates on a first carrier and second candidates on a second carrier, where the distribution is based on aggregation level thresholds. This segmentation reduces the number of blind decodes per carrier while maintaining overall capacity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a new dimension of organization by mapping aggregation levels to specific carriers. Instead of uniformly distributing all candidates across all carriers, it creates a structured dimensional arrangement where different aggregation levels are assigned to different carriers, enabling more efficient blind decoding while maintaining scheduling flexibility.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Productivity

If search spaces are distributed across multiple carriers to increase capacity, then the data transmission capacity is improved, but scheduling restrictions and collisions increase due to overlapping search spaces

Engineering Contradiction:
Improvedata transmission capacityVSAvoidscheduling efficiency
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent segments search spaces by dividing decoding candidates into distinct sets based on aggregation levels and mapping them to different carriers. This segmentation prevents overlapping search spaces and eliminates scheduling collisions while maintaining the ability to serve multiple users across multiple carriers.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by assigning different aggregation levels to different carriers based on their specific characteristics and load conditions. This allows optimized local scheduling on each carrier while maintaining overall system efficiency, reducing collisions and improving reliability.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP2427984B1Downlink control transmission in multicarrier operation
Publication Date: 2019.09.18 QUALCOMM INC
  • EP2427984B1 patent drawingFigure 1
  • EP2427984B1 patent drawingFigure 2
  • EP2427984B1 patent drawingFigure 3

AI summary

A wireless communication network distributes resources for a Physical Downlink Control CHannel (PDCCH) over multiple carriers in accordance with a constraint that limits a number of blind decoding actions required by user equipment (UE). Distribution can entail segregating UE-specific and common search spaces to different monitored carriers. Distribution can entail segregating aggregation levels to different monitored carriers. Distribution can entail segregating a number of decoding candidates for a given aggregation level to different monitored carriers. The distribution can be orthogonal or non-orthogonal, and can be UE-based or per cell-based. The distribution can be static, semi-static or hop with time.