Terminal PUCCH Power Control via MAC CE and Spatial Relations

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Solution Overview

Problem

In next-generation mobile communication systems, the limited number of candidates for power control parameters in uplink transmission can lead to deterioration of system performance if not appropriately determined.

Innovation Solution

The proposed solution involves a method to appropriately determine transmission power control parameters for uplink transmissions in future radio communication systems by using a combination of higher layer signaling and physical layer signaling, specifically through the use of MAC control elements and downlink control information, to manage power control configurations and spatial relations effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the number of power control parameter candidates is limited, then the device complexity is reduced, but the system performance deteriorates due to insufficient power control configurations

Engineering Contradiction:
Improvesystem performanceVSAvoidpower control configurations
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the power control parameter selection into multiple stages: first selecting from a limited set of TPC command values, then refining the selection based on spatial relation information and pathloss reference signals. This segmentation allows the system to maintain manageable complexity in the basic selection mechanism while achieving comprehensive power control through multi-stage refinement, thereby improving system performance without excessive device complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from a one-dimensional power control approach (single TPC command value) to a multi-dimensional approach by introducing spatial relation information and pathloss reference signal selection as additional dimensions. This dimensional expansion enables the system to consider multiple factors simultaneously (TPC command, spatial relation, pathloss) to determine the final power control parameter, thereby improving system performance while keeping the basic device complexity manageable through structured multi-dimensional search.

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

2Reliability

If the number of power control configurations is increased, then the system performance is improved, but the MAC CE size and signaling overhead increase

Engineering Contradiction:
Improvesystem performanceVSAvoidMAC CE size
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The patent applies preliminary action by pre-configuring multiple pathloss reference signals and their associated TPC command values before the actual power control decision is needed. The UE is provided with a set of candidate pathloss reference signals and their corresponding TPC commands in advance, allowing the UE to efficiently select the appropriate configuration based on current spatial relations without requiring extensive real-time signaling. This pre-preparation reduces the need for large MAC CE sizes while maintaining comprehensive power control capabilities.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent utilizes parameter changes by dynamically selecting different TPC command values and pathloss reference signals based on changing spatial relations and channel conditions. Instead of using a fixed, large set of power control configurations, the system adapts the parameters (TPC command, pathloss reference signal) based on current operational requirements. This dynamic parameter selection allows the system to achieve high performance when needed while using minimal signaling overhead when configurations are not required, effectively managing the trade-off between performance and information loss.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3986037B1Terminal and wireless communication method
Publication Date: 2024.07.31 NTT DOCOMO INC
  • EP3986037B1 patent drawingFigure 1
  • EP3986037B1 patent drawingFigure 2
  • EP3986037B1 patent drawingFigure 3

AI summary

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