RSRP-Based Delta Beam Comparison for UL/DL Misalignment

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Solution Overview

Problem

Existing wireless communication technologies face challenges in detecting and correcting UL/DL beam correspondence misalignment, which can lead to reduced link performance and increased cell interference, despite successful DL beam alignment.

Innovation Solution

A method and apparatus for detecting UL/DL beam correspondence misalignment by measuring RSRP for selected and spatially tilted beams using delta power as a comparison metric, involving gNB and UE measurements and reporting, with corrective actions initiated if misalignment is detected.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If DL beam alignment is performed using beamforming techniques, then signal quality at the intended device is improved, but UL/DL beam correspondence misalignment may occur leading to reduced link performance

Engineering Contradiction:
Improvesignal qualityVSAvoidlink performance
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The patent implements a feedback mechanism where the UE measures RSRP for both selected and spatially tilted beams, calculates delta power values, and reports these measurements to the gNB. The gNB uses this feedback to determine beam correspondence status and initiate corrective actions when misalignment is detected, thereby maintaining reliable link performance while using beamforming to improve signal quality.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent performs preliminary beam correspondence verification by measuring RSRP for spatially tilted beams before actual data transmission. The UE calculates delta power values for both DL and UL directions in advance, allowing the system to proactively detect and correct beam misalignment issues before they degrade link performance.

Inventive Principle:
Principle #10Preliminary action

2Productivity

If beamforming is used to achieve higher throughput, then data transmission performance is improved, but beam misalignment detection becomes more difficult

Engineering Contradiction:
ImprovethroughputVSAvoidbeam misalignment detection
Core Design Contradiction:
ProductivityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent introduces spatially tilted beams as intermediary measurement targets to detect beam misalignment. Instead of directly measuring alignment status, the system uses tilted beams at known angular offsets as intermediaries to calculate delta power values, which serve as indicators of beam correspondence status. This intermediary approach simplifies detection while maintaining high throughput beamforming operations.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If beam correspondence verification is performed continuously, then beam alignment accuracy is maintained, but signaling overhead and processing complexity increase

Engineering Contradiction:
Improvebeam alignment accuracyVSAvoidprocessing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent implements partial verification by measuring RSRP for a limited set of spatially tilted beams (e.g., one or two specific tilt angles) rather than exhaustively searching all possible beam directions. This partial action approach maintains sufficient beam alignment accuracy while significantly reducing measurement complexity and signaling overhead compared to complete beam sweeping.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP3817245B1Delta beam comparison for UL/DL beam misalignment detection
Publication Date: 2025.09.24 NOKIA TECHNOLOGIES OY
  • EP3817245B1 patent drawingFigure 1
  • EP3817245B1 patent drawingFigure 2~3
  • EP3817245B1 patent drawingFigure 4

AI summary

In accordance with an example embodiment of the present invention, a method comprising: receiving, by a user equipment of a communication network, a request from a network node to use at least two beam configurations of multiple different beam configurations for the user equipment; measuring, by the user equipment, downlink received power on at least one reference signal using the at least two beam configurations; sending, by the user equipment on an uplink, information of at least two downlink received powers and at least one reference signal using the at least two beam configurations; receiving, by the user equipment, signaling from the network node comprising an indication of beam correspondence assessment from the network node; and adjusting, by the user equipment, uplink beam with reference to a downlink beam based on the received indication of beam correspondence assessment.