Hierarchical Channel State Feedback in CoMP Systems

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Solution Overview

Problem

Current wireless communication systems face challenges in efficiently generating and managing channel state feedback in cooperative communication systems, particularly in Network MIMO (N-MIMO) or Coordinated Multipoint (CoMP) systems, which affects the accuracy and flexibility of downlink communication.

Innovation Solution

The method involves identifying and selecting intra-node and inter-node codebooks via vector quantization to provide channel state feedback, allowing for hierarchical and separable channel state information reporting, which distinguishes between per-node and inter-node channel conditions, optimizing feedback based on coordination strategies and network conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a unified codebook approach is used for channel state feedback in CoMP systems, then the feedback structure is simple, but the accuracy of channel state information deteriorates because it cannot distinguish between per-node and inter-node channel conditions

Engineering Contradiction:
Improvechannel state information accuracyVSAvoidfeedback structure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent divides the channel state feedback into two separate codebooks: intra-node codebooks for per-node channel conditions and inter-node codebooks for inter-node channel conditions. This segmentation allows the system to accurately represent different types of channel information separately, improving overall feedback accuracy without creating a single overly complex unified structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a hierarchical dimension to the feedback structure by organizing codebooks at two levels: intra-node (per-node) and inter-node. This dimensional organization separates the complexity into manageable layers, where each level handles specific aspects of channel state information, thereby improving accuracy while controlling overall complexity.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Measurement precision

If separate intra-node and inter-node codebooks are used, then channel state feedback accuracy improves, but the complexity of managing multiple codebooks increases

Engineering Contradiction:
Improvechannel state feedback accuracyVSAvoidcodebook management complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments codebook management into distinct intra-node and inter-node components, each with specific purposes. This segmentation allows for specialized optimization of each codebook type while maintaining overall system manageability through clear separation of concerns.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent enables dynamic selection and configuration of intra-node and inter-node codebooks based on network conditions and coordination strategies. This dynamic approach allows the system to adapt the level of complexity to actual needs, managing codebook complexity flexibly while maintaining high accuracy when required.

Inventive Principle:
Principle #15Dynamics

3Adaptability or versatility

If traditional channel state feedback methods are used in CoMP systems, then the implementation is straightforward, but the flexibility in adapting to different coordination strategies is limited

Engineering Contradiction:
Improvecoordination strategy adaptabilityVSAvoidfeedback management complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the feedback mechanism into intra-node and inter-node codebooks that can be independently configured and selected based on different coordination strategies (e.g., CBF, JT). This segmentation provides the flexibility to adapt to various strategies without requiring complete redesign of the feedback system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements a dynamic codebook selection mechanism that allows the system to choose appropriate intra-node and inter-node codebooks based on current network conditions and coordination requirements. This dynamic adaptability enables the system to flexibly respond to different coordination strategies while managing complexity through conditional selection rather than fixed structures.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP2351276B1Method and apparatus for separable channel state feedback in a wireless communication system
Publication Date: 2017.11.22 QUALCOMM INC
  • EP2351276B1 patent drawingFigure 1
  • EP2351276B1 patent drawingFigure 2
  • EP2351276B1 patent drawingFigure 3

AI summary

Systems and methodologies are described herein that facilitate the generation and use of separable, hierarchical channel state feedback in a wireless communication system. As described herein, in the event that multiple network nodes cooperate to conduct downlink transmissions to a network user, channel state feedback as reported by the network user can be separated into intra-node feedback relating to per-node channel conditions and inter-node feedback relating to relative phase and/or amplitude between channels corresponding to respective nodes. Further, a network user can select to report intra-node feedback and/or inter-node feedback based on network instructions, a cooperation strategy to be utilized by respective network nodes, or the like. As additionally described herein, respective codebooks on which inter-node and intra-node channel feedback is based can be configured to convey information relating to a partial channel description and/or to vary based on resource units (e.g., sub-bands, resource blocks, etc.) utilized for downlink communication.