MIMO Beamforming Update Rate Adaptation for Overhead Reduction

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Solution Overview

Problem

In multi-access MIMO systems, the creation of beamforming information does not account for differences in user mobility, leading to increased overall transmission overhead as all users' beamforming information is updated at a rate dictated by the most dynamic channels.

Innovation Solution

Divide users into mobility groups based on their levels of mobility, updating beamforming information more frequently for users with higher mobility and less frequently for those with lower mobility, thereby optimizing the transmission of control information.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If beamforming information is updated for all users at a rate dictated by the most dynamic channels, then the beamforming information remains accurate for all users, but the overall transmission overhead increases significantly

Engineering Contradiction:
Improvebeamforming information accuracyVSAvoidtransmission overhead
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent segments users into different mobility groups (stationary, slow-moving, fast-moving) based on their channel dynamics. Each group receives beamforming information at different update rates, allowing the system to maintain accuracy for mobile users while reducing overhead for stationary users. This segmentation resolves the contradiction by applying different update frequencies to different user subsets rather than using a uniform update rate for all users.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by tailoring the beamforming information update rate to the specific mobility characteristics of each user group. Stationary users receive updates less frequently while fast-moving users receive updates more frequently. This localized adaptation of update rates to local user conditions resolves the contradiction between maintaining accuracy for all users and reducing overall transmission overhead.

Inventive Principle:
Principle #3Local quality

2Quantity of substance

If beamforming information is updated less frequently for stationary users, then transmission overhead is reduced, but the system must maintain accurate beamforming information for mobile users

Engineering Contradiction:
Improvetransmission overheadVSAvoidmobility adaptation
Core Design Contradiction:
Quantity of substanceVSAdaptability or versatility

Solution Approach 1:

The patent implements dynamics by making the beamforming information update rate adaptive to user mobility conditions. The system dynamically adjusts update frequencies based on measured channel dynamics, allowing stationary users to receive updates less frequently while mobile users receive updates more frequently. This dynamic adaptation resolves the contradiction between reducing overhead and maintaining adaptability to different mobility scenarios.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of update frequency based on user mobility characteristics. By measuring channel dynamics and adjusting the update rate parameter accordingly, the system reduces overhead for stationary users while maintaining accurate beamforming information for mobile users. This parameter change resolves the contradiction by making the update rate flexible rather than fixed.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2097993A1Reduction of overhead in a multiple-input multiple-output (MIMO) system
Publication Date: 2009.09.09 THOMSON LICENSING SA

AI summary

A multi-access multiple-input multiple-output (MIMO) system comprises a base station (BS) and a number of user equipment (UE),N, for serving N users. The BS divides the N users into L mobility groups, where each mobility group is associated with a certain range of channel dynamics. Those mobility groups having lower channel dynamics - that is, the channel dynamics change less rapidly - are updated with beamforming information less frequently than those mobility groups having higher dynamics - that is, the channel dynamics change more rapidly.