User Terminal Search Space Configuration for PDCCH Monitoring

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Solution Overview

Problem

In existing LTE systems, the lack of appropriate configuration methods for search spaces associated with control resource sets (CORESETS) leads to increased communication traffic and degradation in communication throughput and frequency use efficiency, as user equipment (UE) cannot accurately identify the type of search space or detect the correct DCI formats and RNTIs without proper type differentiation.

Innovation Solution

The introduction of search space type information within the search space configuration, allowing the UE to identify the type of search space and specify DCI formats and RNTIs to be detected, enabling proper monitoring of PDCCH candidates and reducing unnecessary communication traffic.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If search space configuration does not include type information, then the configuration is simpler, but the UE cannot accurately identify search space type or detect correct DCI formats and RNTIs

Engineering Contradiction:
Improvesearch space type identification accuracyVSAvoidsearch space configuration complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The search space configuration is segmented by introducing type information that divides search spaces into distinct categories (common search space and UE-specific search space). This segmentation enables the UE to accurately identify the type of each search space and apply appropriate detection rules for DCI formats and RNTIs, resolving the contradiction between identification accuracy and configuration simplicity.

Inventive Principle:
Principle #1Segmentation

2Reliability

If UE monitors all DCI formats without type differentiation, then the UE can detect any possible DCI, but communication traffic increases and throughput degrades

Engineering Contradiction:
ImproveDCI detection reliabilityVSAvoidcommunication throughput
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The invention applies local quality by assigning different properties to different search space types. Common search spaces are configured to monitor specific DCI formats with specific RNTIs, while UE-specific search spaces monitor different DCI formats with different RNTIs. This localized differentiation ensures reliable DCI detection while avoiding unnecessary monitoring of irrelevant DCI formats, thus maintaining high communication throughput.

Inventive Principle:
Principle #3Local quality

3Reliability

If UE monitors all search spaces without type information, then no DCI is missed, but frequency use efficiency decreases due to unnecessary traffic

Engineering Contradiction:
ImproveDCI detection completenessVSAvoidfrequency use efficiency
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The invention implements preliminary action by pre-configuring search space type information and associated DCI format/RNTI mappings before the UE begins monitoring. This allows the UE to proactively filter and monitor only the relevant DCI formats for each search space type, ensuring complete detection of necessary DCI while avoiding unnecessary monitoring that would waste frequency resources and reduce efficiency.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3739996B1User terminal and wireless communication method
Publication Date: 2023.12.20 NTT DOCOMO INC
  • EP3739996B1 patent drawingFigure 1
  • EP3739996B1 patent drawingFigure 2
  • EP3739996B1 patent drawingFigure 3

AI summary

A user terminal according to an aspect of the present disclosure includes a control section that determines a type of particular search space, based on certain information included in a search space configuration, and a receiving section that monitors a control resource set (CORESET) by using the particular search space. The control section is configured to necessarily determine at least two types including a type of search space for detecting a downlink control information format with CRC (Cyclic Redundancy Check) scrambled by a random access RNTI (Radio Network Temporary Identifier) and a type of user terminal-specific search space, based on one or a plurality of search space configurations. According to an aspect of the present disclosure, it is possible to appropriately associate a search space with a CORESET.