EPDCCH Search Space Offset Allocation for LTE Resource Conflict Reduction

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Solution Overview

Problem

The existing methods for determining control channel search spaces in LTE systems lead to control channel congestion and search space conflicts, especially as the number of users increases, due to the shared use of resources by multiple EPDCCH sets or UEs.

Innovation Solution

The method involves determining different location offsets for various EPDCCH search spaces by grouping and numbering time-frequency resources, allowing for unique allocation of EPDCCH sets and reducing the probability of search space conflicts through specific formulas and offset calculations based on UE identifiers and resource allocation modes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If multiple EPDCCH sets or UEs use the same search space according to prior art methods, then resource allocation is simplified, but control channel congestion and search space conflicts occur seriously when the number of users increases

Engineering Contradiction:
Improvesearch space allocation complexityVSAvoidcontrol channel transmission reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent segments the search space by introducing different location offsets for different EPDCCH sets. Each EPDCCH set is assigned a unique location offset value, which divides the originally shared search space into separate segments. This segmentation prevents multiple EPDCCH sets from occupying the same search space resources, thereby eliminating search space conflicts while maintaining manageable allocation complexity through systematic offset assignment.

Inventive Principle:
Principle #1Segmentation

2Quantity of substance

If the number of users increases in the LTE system, then network capacity and service coverage are improved, but control channel congestion and search space conflicts become more serious

Engineering Contradiction:
Improvenumber of usersVSAvoidcontrol channel transmission reliability
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent introduces a new dimension for search space differentiation by assigning location offsets along the frequency domain. Instead of allowing users to share the same search space, the location offset parameter creates an additional dimensional space for separating user-specific search spaces. This dimensional expansion enables the system to accommodate more users without increasing control channel congestion, as each user's EPDCCH is positioned at a unique offset location.

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

Data Source

PatentEP3611971B1Method and apparatus for determining control channel search space
Publication Date: 2022.01.26 HUAWEI TECH CO LTD
  • EP3611971B1 patent drawingFigure 1~2
  • EP3611971B1 patent drawingFigure 3~4
  • EP3611971B1 patent drawingFigure 5~6

AI summary

Embodiments of the present invention provide a method for determining a control channel search space. The method includes: determining numbers of EPDCCH sets used for enhanced physical downlink control channel EPDCCH transmission; determining, according to the numbers of the EPDCCH sets, location offsets of search spaces corresponding to the EPDCCH sets; and determining, according to the location offsets of the search spaces corresponding to the EPDCCH sets, the search spaces corresponding to the EPDCCH sets. The embodiments of the present invention further provide an apparatus for determining a control channel search space. By grouping and numbering time frequency resources of EPDCCHs, and determining different location offsets for different EPDCCH search spaces according to the numbers and different cell identities or UE identifiers, a probability of control channel search space conflict can be reduced. Thereby, time frequency resources of control channels can be maximized in a case of multiple users, and communication efficiency can be improved.