Dynamic Joint-Codebooks for Mobile Active Coordination Sets

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Solution Overview

Problem

In wireless communication systems transitioning to 5G and 6G, UE mobility causes frequent changes in the base stations included in an Active Coordination Set (ACS), necessitating dynamic adjustments in codebooks to maintain effective precoding feedback and data transmission.

Innovation Solution

A method where a base station generates a joint-codebook for an ACS based on capability information from other base stations, jointly transmits it to the UE, and processes downlink data using Precoding Matrix Indicator (PMI) feedback to ensure phase coherence and improved data transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a joint-codebook is generated and transmitted to the UE to enable precoding feedback, then data transmission efficiency is improved, but signaling overhead increases

Engineering Contradiction:
Improvedata transmission efficiencyVSAvoidsignaling overhead
Core Design Contradiction:
ProductivityVSQuantity of substance

Solution Approach 1:

The codebook is segmented into two parts: a first codebook containing first codebook entries and a second codebook containing second codebook entries. The UE is configured to select entries from both codebooks independently, allowing the base station to transmit only the codebook structures rather than all possible precoding matrices, thereby reducing signaling overhead while maintaining data transmission efficiency through coordinated multi-point precoding.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If codebooks are dynamically adjusted to accommodate UE mobility and ACS changes, then adaptability is improved, but system complexity increases

Engineering Contradiction:
Improveadaptability to UE mobilityVSAvoidsystem complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The system dynamically adjusts the codebook configuration based on UE mobility and changes in the active coordination set. The base station determines which codebook entries to include in the first and second codebooks based on current channel conditions and UE location, enabling the system to adapt to mobility while managing complexity through structured codebook management rather than complete reconfiguration.

Inventive Principle:
Principle #15Dynamics

3Measurement precision

If multiple codebooks are used for different base stations in the ACS, then precoding accuracy is improved, but processing complexity increases

Engineering Contradiction:
Improveprecoding accuracyVSAvoidprocessing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The codebook is divided into first codebook entries associated with first base stations and second codebook entries associated with second base stations in the ACS. The UE selects entries from both segmented codebooks to form the final precoding matrix, allowing accurate precoding for multiple base stations while reducing processing complexity through structured organization and selective combining rather than processing all possible combinations.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP4278446B1Dynamic codebooks for active coordination sets
Publication Date: 2025.08.13 GOOGLE LLC
  • EP4278446B1 patent drawingFigure 1
  • EP4278446B1 patent drawingFigure 2
  • EP4278446B1 patent drawingFigure 3

AI summary

This document describes methods, devices, systems, and means for determining a joint-codebook for wireless communication with a user equipment, UE, by a base station in an active coordination set, ACS, in which a base station receives capability information from one or more other base stations in the ACS (702). The base station generates a joint-codebook for the ACS based on the received capability information (704) and sends the joint-codebook to the one or more other base stations in the ACS (706). The base station and the other base stations in the ACS jointly-transmit the joint-codebook to the UE (708) and receive Precoding Matrix Indicator, PMI, feedback from the UE (710). The base station and the other base stations in the ACS jointly-process downlink data for the UE using the PMI feedback and the joint-codebook (712) and jointly-transmit the downlink data to the UE (714).