CoMP CSI Feedback via Segmented Processes

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

In the LTE-Advanced system, the existing framework for carrier aggregation does not support the feedback of multiple pieces of Channel State Information (CSI) with respect to each transmission point when Coordinated Multi-Point (CoMP) transmission is applied, which is necessary for achieving optimal interference management and throughput enhancement.

Innovation Solution

A radio communication system that includes a radio base station apparatus and user terminal configured for CoMP transmission, where CSI set information is transmitted through higher layer signaling, and CSI request information is included in downlink control information, allowing the user terminal to feed back CSI based on the received information.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the existing carrier aggregation framework is used, then backward compatibility with LTE system is maintained, but multiple pieces of CSI cannot be fed back with respect to each transmission point when CoMP transmission is applied

Engineering Contradiction:
ImproveCSI feedback capability for CoMP transmissionVSAvoidcarrier aggregation framework complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the CSI feedback mechanism by introducing separate CSI process identifiers that can independently report channel state information for different transmission points. This allows multiple CSI reports to be generated and fed back within the existing carrier aggregation framework, enabling CoMP transmission without requiring a complete framework overhaul.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent configures multiple CSI processes and their parameters in advance through higher layer signaling (RRC configuration) before CoMP transmission occurs. This preliminary configuration establishes the foundation for multi-CSI feedback capability, allowing the system to adapt to CoMP requirements while maintaining the existing carrier aggregation structure.

Inventive Principle:
Principle #10Preliminary action

2Productivity

If multiple pieces of CSI are fed back for each transmission point, then interference management and throughput are improved, but signaling overhead increases

Engineering Contradiction:
Improvesystem throughputVSAvoidsignaling overhead
Core Design Contradiction:
ProductivityVSLoss of information

Solution Approach 1:

The patent makes the existing CSI feedback mechanism universal by enabling it to serve both traditional carrier aggregation and CoMP transmission scenarios. Through configurable CSI processes that can be associated with different transmission points, the same feedback channel structure handles multiple functions, reducing the need for separate dedicated signaling paths and thereby controlling overhead while supporting enhanced throughput.

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

3Reliability

If CoMP transmission is applied, then interference management is enhanced, but the existing framework does not support multiple CSI feedback

Engineering Contradiction:
Improveinterference managementVSAvoidframework compatibility
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent introduces dynamic associability between CSI processes and transmission points through configurable parameters. This dynamic relationship allows the system to adapt the CSI feedback structure to match the actual CoMP transmission configuration, enabling enhanced interference management while maintaining compatibility with the existing framework through flexible, reconfigurable associations rather than rigid structural changes.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP2858407B1Wireless communication system and wireless communication method
Publication Date: 2021.06.02 NTT DOCOMO INC
  • EP2858407B1 patent drawingFigure 1
  • EP2858407B1 patent drawingFigure 2A~2B
  • EP2858407B1 patent drawingFigure 3

AI summary

The present invention is designed to feed back a plurality of pieces of CSI with respect to each transmission point, when CoMP transmission is applied in the framework of carrier aggregation. The radio communication method according to the present invention is a radio communication method in a radio communication system including a plurality of radio base station apparatuses and a user terminal that is configured to be able to perform coordinated multi-point transmission/reception with the plurality of radio base station apparatuses, and, in this radio communication method, when coordinated multi-point transmission is applied, the radio base station apparatus, transmits CSI set information on a set including at least one CSI through higher layer signaling, and also transmits CSI request information in DCI, and the user terminal feeds back CSI based on the CSI set information and the CSI request information.