PDCCH Repetition Resource Allocation for NTN Coverage

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Solution Overview

Problem

In non-terrestrial networks (NTN), the physical downlink control channel (PDCCH) faces challenges in coverage enhancement due to large propagation delays and satellite movement, which affect the reliability and efficiency of initial access and data transmission.

Innovation Solution

The proposed solution involves determining and transmitting transmission resources for a set of repetitions of the PDCCH, allowing terminal devices to monitor and combine these repetitions, thereby improving coverage and reducing latency and buffer size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If PDCCH repetitions are transmitted in NTN, then coverage enhancement is improved, but propagation delay and satellite movement reduce reliability

Engineering Contradiction:

Improvecoverage enhancementVSAvoidpropagation delay and satellite movement

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The PDCCH transmission is segmented into multiple repetitions transmitted at different time instances. Each repetition carries the same control information, allowing the terminal to combine them for improved reliability. This segmentation approach directly addresses the coverage enhancement need while managing the effects of propagation delay and satellite movement by distributing transmissions across multiple opportunities.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The terminal device determines transmission resources for PDCCH repetitions in advance and monitors for these repetitions according to predetermined patterns. This preliminary configuration allows the system to prepare for the effects of satellite movement and propagation delay by establishing monitoring expectations before the actual transmissions occur, improving the ability to reliably receive and combine repetitions.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If multiple PDCCH repetitions are monitored, then coverage is enhanced, but terminal device complexity increases

Engineering Contradiction:

ImprovecoverageVSAvoidterminal device complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Multiple copies of the same PDCCH information are transmitted through repetitions. The terminal device monitors for these copies and combines them to achieve the desired coverage enhancement. This copying approach allows coverage improvement without requiring the terminal to process fundamentally different or more complex information structures, thereby limiting the increase in device complexity.

Inventive Principle:

Principle #26Copying

Data Source

PatentUS20250039897A1Mechanism for repetition of physical downlink control channel

Publication Date: 2025.01.30 NOKIA TECHNOLOGIES OY

AI summary

The present disclosure relates to a solution for PDCCH repetition. In particular, a terminal device determines transmission resources for a set of repetitions of a physical downlink control channel (PDCCH). The terminal device monitors the set of repetitions of the PDCCH from a network device based on the transmission resources. In this way, it can reduce latency for the terminal device and can also decrease a buffer size at the terminal device.