ePDCCH Candidate Allocation for Reduced Blind Detection Complexity

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Solution Overview

Problem

In LTE communication systems, the existing methods do not effectively reduce the complexity of blind detection for control channel candidates, particularly in the allocation of ePDCCH resources, which increases the number of blind decoding attempts and resource utilization challenges.

Innovation Solution

The method involves determining K sets for transmitting a control channel, allocating control channel candidates at each aggregation level to at least one set among the K sets, based on the supported aggregation levels, number of candidates, and types of sets, to define a search space that reduces the complexity of blind detection for UEs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the number of CCEs in the PDCCH region is increased to support more UEs, then the capacity of the system is improved, but the number of blind detections required by each UE increases proportionally, increasing complexity

Engineering Contradiction:
Improvesystem capacityVSAvoidblind detection complexity
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The PDCCH region is segmented into multiple search spaces (common search space and UE-specific search space) with different starting positions and candidate distributions. This segmentation allows the system to support more UEs by distributing control channel candidates across different regions, while each UE only needs to detect candidates in its assigned search space, maintaining constant blind detection complexity regardless of system capacity increases.

Inventive Principle:
Principle #1Segmentation

2Device complexity

If the maximum number of PDCCH candidates is limited to reduce blind detection complexity, then the complexity is reduced, but the ability to support multiple aggregation levels and transmission modes is constrained

Engineering Contradiction:
Improveblind detection complexityVSAvoidaggregation level support
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

Different aggregation levels (L=1, 2, 4, 8) are assigned different numbers of candidates and distributed to different search spaces based on their specific requirements. Lower aggregation levels with fewer candidates are placed in the common search space, while higher aggregation levels with more candidates are placed in the UE-specific search space. This local quality differentiation allows the system to support multiple aggregation levels and transmission modes while keeping the total number of blind detections constant for each UE.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3713144B1Method and apparatus for allocating control channel candidates
Publication Date: 2021.11.03 HUAWEI TECH CO LTD
  • EP3713144B1 patent drawingFigure 1~2
  • EP3713144B1 patent drawingFigure 3
  • EP3713144B1 patent drawing

AI summary

The present invention provides a method and an apparatus for allocating control channel candidates, which relate to the communications field, and can allocate control channel candidates at different aggregation levels to K ePDCCH sets and reduce complexity of blind detection performed by a UE. The method includes: determining K sets for transmitting a control channel, where each set in the K sets includes at least one physical resource block pair; and allocating control channel candidates at each aggregation level to at least one set in the K sets according to at least one of aggregation levels supported by the control channel to be transmitted, the number of control channel candidates corresponding to each aggregation level, the K sets for transmitting the control channel, and types of the sets.