PUCCH Pathloss Reference Selection for Uplink Power Control

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Solution Overview

Problem

In future radio communication systems, the limited number of candidates for power control parameters in uplink transmission of PUCCH, PUSCH, and SRS leads to potential system performance deterioration unless appropriately determined.

Innovation Solution

A method for appropriately determining transmission power control parameters by utilizing TCI states and spatial relations, including MAC CE and RRC signaling, to enhance power control configurations for PUCCH, PUSCH, and SRS.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the number of power control parameter candidates is increased to improve transmission accuracy, then the system complexity and configuration overhead increase

Engineering Contradiction:
Improvepower control parameter determination accuracyVSAvoidparameter configuration complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by pre-configuring multiple power control parameter candidates through RRC signaling before transmission occurs. The terminal device stores these pre-defined parameter sets (including pathloss reference signal IDs, P0 values, and alpha values) and can quickly select from them based on DCI indications, avoiding the need to configure all parameters in real-time and thus reducing configuration overhead while maintaining accuracy.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent segments the power control parameter configuration into multiple independent candidate sets, each associated with different transmission scenarios. By dividing the parameter space into discrete, pre-configured options that can be independently selected via DCI field indications, the system achieves fine-grained control without requiring complex real-time calculations, thereby balancing precision with manageable complexity.

Inventive Principle:
Principle #1Segmentation

2Reliability

If multiple power control parameter candidates are configured to improve transmission reliability, then the signaling overhead and configuration complexity increase

Engineering Contradiction:
Improveuplink transmission reliabilityVSAvoidsignaling overhead
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The patent makes the power control parameter configuration universal by creating a set of candidate parameters that can serve multiple uplink channels (PUCCH, PUSCH, SRS) and multiple transmission scenarios. Instead of configuring separate parameters for each channel or scenario, a single unified candidate set is configured via RRC and can be selectively applied through DCI indications, reducing redundant signaling overhead while maintaining reliability across diverse transmission conditions.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Productivity

If real-time power control parameter adjustment is implemented to improve system performance, then the processing complexity and response time requirements increase

Engineering Contradiction:
Improvesystem performanceVSAvoidparameter adjustment complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by pre-calculating and storing multiple power control parameter candidates before transmission occurs. The terminal device prepares these parameter sets in advance through RRC configuration, so when real-time adjustment is needed, the device only needs to select from the pre-prepared options based on simple DCI indications rather than performing complex real-time calculations, thus achieving fast response with reduced processing complexity.

Inventive Principle:
Principle #10Preliminary action

4Measurement precision

If the pathloss reference signal is automatically updated to follow spatial relation changes, then the power control accuracy improves, but the configuration management complexity increases

Engineering Contradiction:
Improvepower control accuracyVSAvoidconfiguration management ease
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent applies self-service by enabling the pathloss reference signal to automatically follow spatial relation changes without requiring manual reconfiguration. When the spatial relation for uplink transmission changes (indicated by DCI), the terminal device automatically updates the associated pathloss reference signal ID to match the new spatial relation, ensuring power control accuracy is maintained dynamically. This automatic linkage simplifies configuration management by eliminating the need for separate manual updates of pathloss reference signals.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3986040B1Terminal and wireless communication method
Publication Date: 2026.03.18 NTT DOCOMO INC
  • EP3986040B1 patent drawingFigure 1
  • EP3986040B1 patent drawingFigure 2
  • EP3986040B1 patent drawingFigure 3

AI summary

A terminal according to one aspect of the present disclosure includes: a control section that determines a reference signal for pathloss reference for a physical uplink control channel (PUCCH), based on any one of reception of a medium access control control element (MAC CE) and transmission of a random access channel; and a transmitting section that transmits the PUCCH by using transmission power based on the reference signal for pathloss reference. According to one aspect of the present disclosure, a parameter for transmission power control can be appropriately determined.