PDCCH Repetition Configuration for NTN Coverage

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Solution Overview

Problem

In non-terrestrial networks (NTN), the PDCCH channel performance is affected by satellite power limitations, leading to challenges in initial access and coverage enhancement, particularly in scenarios where Power Flux Density (PFD) limits are imposed.

Innovation Solution

The proposed solution involves configuring repetitions of physical downlink control channel (PDCCH) candidates in an additional random access (RA) search space, allowing terminal devices to monitor downlink control information based on the configuration of the original RA search space and the repetitions in the additional RA search space.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If satellite power limitations are imposed, then energy consumption is reduced, but PDCCH channel performance deteriorates

Engineering Contradiction:

Improvesatellite power consumptionVSAvoidPDCCH channel performance

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The PDCCH transmission is segmented into multiple repetitions across different time slots. Each repetition carries the same downlink control information, allowing the terminal to combine multiple segments to achieve the required reliability while the satellite transmits at reduced power levels.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system configures multiple PDCCH monitoring occasions and repetitions in advance through RA search space configuration. This preliminary arrangement ensures that even with limited satellite power, the terminal can successfully decode control information by combining multiple pre-configured repetitions.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If repetitions of PDCCH candidates are configured, then coverage is enhanced, but device complexity increases

Engineering Contradiction:

ImprovecoverageVSAvoidmonitoring complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The system dynamically configures the number of PDCCH repetitions and monitoring occasions based on terminal capability and channel conditions. This dynamic approach allows coverage enhancement while adapting the monitoring complexity to actual needs, preventing unnecessary complexity in good channel conditions.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The configuration parameters such as monitoringSlotPeriodicityAndOffset, duration, and nrofCandidates are adjusted to control the number of repetitions. By changing these parameters, the system can achieve coverage enhancement while managing terminal complexity through standardized parameter sets.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If multiple monitoring occasions are configured, then reliability is improved, but time consumption increases

Engineering Contradiction:

Improvedemodulation reliabilityVSAvoidaccess time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

Multiple PDCCH monitoring occasions are merged into a unified RA search space configuration. The terminal combines signals from multiple monitoring occasions to improve demodulation reliability, while the network coordinates these occasions to minimize overall access time through efficient resource allocation.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS20250039940A1Configuration of repetitions of downlink control information

Publication Date: 2025.01.30 NOKIA TECHNOLOGIES OY

AI summary

Embodiments of the present disclosure relate to apparatuses, methods, and computer readable storage media for a configuration of repetitions of downlink control information (DCI). The method comprises: receiving, from a second apparatus, a configuration of an random access (RA) search space; determining an additional RA search space including repetitions of physical downlink control channel (PDCCH) candidates of at least one monitoring occasion of the RA search space; and monitoring downlink control information at least based on the configuration of the RA search space and the repetitions in the additional RA search space.