CSI-RS Resource Allocation for Beam Gain Measurement

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Solution Overview

Problem

Conventional radio communication systems fail to provide accurate channel estimation for mobile stations due to the same channel state information-reference signal (CSI-RS) being transmitted to all mobile stations, which hinders the differentiation of beam gains and increases signaling overhead.

Innovation Solution

A method where the base station generates beams corresponding to reference signals by precoding based on the channel direction of each mobile station and notifies the mobile station of specific reference signal resources for measurement, allowing each station to accurately measure beam gains using selected resources.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the same CSI-RS is transmitted to all mobile stations, then the transmission process is simple, but the channel estimation accuracy deteriorates because mobile stations cannot differentiate beam gains

Engineering Contradiction:
Improvechannel estimation accuracyVSAvoidtransmission complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the reference signal transmission by allocating different CSI-RS resources to different mobile stations. Each mobile station is assigned specific resource elements for CSI-RS transmission, allowing it to measure beam gains accurately for its designated resources while other stations measure their own allocated resources. This segmentation enables precise channel estimation without requiring all stations to process all resources.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by transmitting CSI-RS with beamforming specifically tailored to each mobile station's location and channel characteristics. Each mobile station receives optimized reference signals adapted to its specific spatial position, enabling accurate local channel estimation and beam gain differentiation without affecting other stations.

Inventive Principle:
Principle #3Local quality

2Measurement precision

If beamforming is applied to CSI-RS for each mobile station, then channel estimation accuracy improves, but the signaling overhead increases

Engineering Contradiction:
Improvechannel estimation accuracyVSAvoidsignaling overhead
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The patent extracts and removes unnecessary signaling overhead by eliminating the need to inform mobile stations about all possible beamforming configurations. Instead, each mobile station is simply notified of its specific allocated CSI-RS resources, and the beamforming parameters are implicitly determined by the network based on station location and channel conditions, reducing signaling burden while maintaining accuracy.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Mobile stations perform self-service by autonomously measuring channel quality and beam gains on their allocated CSI-RS resources without requiring extensive network coordination. The stations independently complete channel estimation and feedback, reducing the need for complex signaling exchanges between network and devices.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3300441B1Mobile station, base station and radio communication method
Publication Date: 2020.11.25 NTT DOCOMO INC
  • EP3300441B1 patent drawingFigure 1
  • EP3300441B1 patent drawingFigure 2
  • EP3300441B1 patent drawingFigure 3

AI summary

The present invention provides a mobile station, a base station and a radio communication method. A mobile station pertaining to the present invention is provided, including a receiving section configured to receive information that indicates at least one reference signal resource and measurement window information that indicates an allocation of a measurement window; a measuring section configured to measure a reference signal, to which precoding has been applied, based on the information that indicates the at least one reference signal resource and the measurement window information, and to generate a measurement result; and a transmitting section configured to transmit the measurement result.