Backhaul Downlink Power Control to Reduce Relay Interference

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Solution Overview

Problem

In 4G LTE and 5G NR systems, the power difference between downlink, uplink, and next-hop uplink signals at relay nodes causes severe interference, with existing power control mechanisms inadequate for downlink transmission on the backhaul link.

Innovation Solution

A power control method and apparatus that determines transmit power for downlink signals on the backhaul link using first information sent by a second node, incorporating path loss compensation and power control parameters to minimize interference with access and next-hop uplink signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If power control is performed on uplink signals but not on downlink backhaul signals, then uplink signal quality is improved, but downlink-backhaul interference remains severe

Engineering Contradiction:
Improveuplink signal qualityVSAvoiddownlink-backhaul interference
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent extends the power control mechanism from uplink-only to both uplink and downlink transmissions. The base station now performs power control for downlink backhaul signals in addition to uplink signals, making the power control system universal across all transmission directions and resolving the interference issue while maintaining uplink quality.

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

Solution Approach 2:

The patent introduces dynamic adjustment of downlink transmit power parameters. The base station determines downlink power parameters based on feedback from relay nodes about received power levels, enabling adaptive parameter changes that reduce interference while maintaining reliable communication.

Inventive Principle:
Principle #35Parameter changes

2Area of stationary object

If downlink transmit power is increased to improve coverage, then coverage area is improved, but interference with uplink signals increases

Engineering Contradiction:
Improvecoverage areaVSAvoidinterference with uplink signals
Core Design Contradiction:
Area of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The patent implements a feedback mechanism where relay nodes measure the received downlink power and feed back this information to the base station. The base station uses this feedback to adjust downlink transmit power dynamically, achieving coverage optimization while preventing excessive interference through continuous monitoring and adjustment.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent transitions from static power allocation to dynamic power control. Downlink transmit power is no longer fixed but adjusts dynamically based on real-time channel conditions and interference levels, allowing the system to optimize coverage while minimizing interference through continuous adaptation.

Inventive Principle:
Principle #15Dynamics

3Device complexity

If power control parameters are not configured for downlink backhaul transmission, then system complexity is reduced, but power control capability is insufficient

Engineering Contradiction:
Improvesystem complexityVSAvoidpower control capability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent configures downlink power control parameters in advance through higher layer signaling (RRC signaling) before actual data transmission begins. This preliminary configuration establishes the power control framework upfront, avoiding complex real-time calculations during transmission while ensuring adequate power control capability is in place.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3720200B1Power control method and apparatus
Publication Date: 2025.08.06 HUAWEI TECH CO LTD
  • EP3720200B1 patent drawingFigure 1~2
  • EP3720200B1 patent drawingFigure 3~4
  • EP3720200B1 patent drawingFigure 5~6

AI summary

This application discloses a power control method and apparatus. The method includes: receiving, by a first node, first information sent by a second node, where the first information is used to determine a first transmit power, the first transmit power is a power used when the first node sends downlink information to the second node through a first link, the first link is a link between the first node and the second node, and the first node is an upper-level device of the second node; and determining, by the first node, the first transmit power based on the first information. Therefore, the first node determines the first transmit power based on the first information, and uses the first transmit power when sending the downlink information to the second node through the first link, so that interference between signals received by the second node can be reduced.