Base Station CSI-RS Allocation for Interference Management

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Solution Overview

Problem

In next-generation mobile communication systems, as the number of antennas increases, existing technologies face challenges in adequately transmitting and receiving reference signals, particularly for mobile terminal apparatuses capable of Multiple-Input Multiple-Output (MIMO) transmission, leading to interference and reduced demodulation accuracy.

Innovation Solution

A base station apparatus allocates reference signals to defined resources that can be muted, reporting these allocations to mobile terminal apparatuses with varying numbers of supported antennas, allowing them to disregard interfering signals and maintain channel state measurement accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the number of antennas in the base station increases to improve data rates and channel state measurement accuracy, then the channel state estimation quality improves, but interference increases and mobile terminal apparatuses with fewer antennas cannot adequately receive and measure reference signals

Engineering Contradiction:
Improvechannel state measurement accuracyVSAvoidinterference
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The reference signals are segmented and allocated to specific resource elements in a structured pattern. The base station transmits reference signals from multiple antennas to specific resource elements, and mobile terminal apparatuses are configured to measure reference signals from a predetermined number of antennas, dividing the measurement task across multiple terminals to handle the increased antenna count effectively

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different mobile terminal apparatuses are assigned different measurement configurations based on their capabilities. Terminals with fewer antennas measure reference signals from a predetermined subset of antennas, while the system overall benefits from the increased antenna diversity. This local adaptation allows each terminal to operate optimally within its capabilities while the system achieves improved channel state estimation

Inventive Principle:
Principle #3Local quality

2Measurement precision

If reference signals are transmitted from a larger number of antennas to improve channel state estimation, then measurement accuracy improves, but mobile terminal apparatuses capable of receiving reference signals from a smaller number of antennas are unable to adequately receive and measure them

Engineering Contradiction:
Improvechannel state estimationVSAvoidcompatibility with mobile terminals
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The system dynamically adapts the reference signal measurement configuration based on mobile terminal capabilities. The base station configures mobile terminal apparatuses to measure reference signals from a predetermined number of antennas, allowing the system to optimize channel state estimation while maintaining compatibility with terminals having different antenna counts and capabilities

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The reference signal allocation pattern is designed to be universally compatible with mobile terminal apparatuses having different antenna capabilities. By allocating reference signals in a standardized pattern and allowing terminals to measure from a predetermined number of antennas, the system achieves multi-functionality that serves both advanced terminals with high measurement capabilities and legacy terminals with fewer antennas

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

Data Source

PatentEP2677828B1Base station device, mobile terminal device, and communication control method
Publication Date: 2023.11.15 NTT DOCOMO INC
  • EP2677828B1 patent drawingFigure 1A~1D
  • EP2677828B1 patent drawingFigure 2A~2B
  • EP2677828B1 patent drawingFigure 3

AI summary

The present invention makes it possible to transmit and receive CSI-RSs adequately even when the number of CSI-RSs increase following the increase of antennas. The present invention provides a base station apparatus (20) that transmits CSI-RSs to a mobile terminal apparatus (10A) which is capable of receiving CSI-RSs for channel state measurement from a plurality of antennas, and to a mobile terminal apparatus (10B) which is capable of receiving CSI-RSs from a smaller number of antennas than the mobile terminal apparatus, and this base station apparatus has a CSI-RS allocation section (211) which allocates CSI-RSs for the number of antennas which the mobile terminal apparatus (10A) supports, to radio resources, and a transmitting/receiving section which reports, to the mobile terminal apparatus (10A), the resources where the CSI-RSs are allocated, and which, upon reporting the resources where CSI-RSs are allocated, to the mobile terminal apparatus (10B), reports part of the resources as resources to be muted.