MU-MIMO Precoder Selection via UE Correlation

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Solution Overview

Problem

Current MU-MIMO systems face inefficiencies in pre-coding, particularly when receivers are close to each other, leading to potential failures and suboptimal transmission capacity.

Innovation Solution

A method for precoding in MU-MIMO systems that selects User Equipments (UEs) based on correlation values calculated from precoder matrix indicators and channel matrices, generating precoders using a 2-stage codebook and Lagrange multipliers to minimize interference and improve transmission capacity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional pre-coding methods are used in MU-MIMO systems, then the system can operate with simple pre-coding mechanisms, but pre-coding failures occur and transmission capacity is suboptimal when receivers are close to each other

Engineering Contradiction:
Improvepre-coding success rateVSAvoidpre-coding mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent changes the parameters used in pre-coding by introducing correlation values calculated from precoder matrix indicators and channel matrices. Instead of using fixed pre-coding matrices, the system dynamically selects precoders based on calculated correlation values between UEs, thereby improving pre-coding reliability while adapting to different spatial configurations of receivers

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements dynamic pre-coding by continuously calculating correlation values and selecting optimal precoders based on current channel conditions. The system transitions from static pre-coding to a dynamic process where precoders are selected based on real-time correlation measurements between users, enabling the system to adapt to changing spatial relationships

Inventive Principle:
Principle #15Dynamics

2Productivity

If multiple UEs are scheduled for simultaneous transmission, then transmission capacity increases, but interference between closely located receivers increases

Engineering Contradiction:
Improvetransmission capacityVSAvoidinterference between receivers
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent employs feedback mechanisms where UEs report precoder matrix indicators and channel state information. The base station uses this feedback to calculate correlation values and select appropriate precoders, creating a closed-loop system that continuously adapts to minimize interference while maximizing transmission capacity

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent applies local quality by calculating correlation values specific to each UE pair's spatial relationship. Instead of using uniform pre-coding for all users, the system tailors pre-coding parameters to the specific spatial configuration of each UE pair, thereby reducing interference between closely located receivers while maintaining capacity for multiple simultaneous transmissions

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP2898721B1Method for improving transmission capacity in a dl MU-MIMO communications system
Publication Date: 2018.06.06 NEC CORP
  • EP2898721B1 patent drawingFigure 1~2
  • EP2898721B1 patent drawingFigure 3
  • EP2898721B1 patent drawingFigure 4

AI summary

A method according to the present invention is for selecting User Equipment (UE) for scheduling/precoding within the coverage area of a communications node having a predefined codebook. The method includes: receiving at the communications node feedback information from each of the UEs within the coverage area of the communications node wherein the feedback information includes at least one precoder matrix indicator (PMI); generating at the communications node a precoder matrix based on the reported precoder matrix indicator from each UE; determining at the communications node correlation values for each UE in the coverage utilising the precoder matrix; identifying a pair of UEs having minimum correlation values; and selecting the identified UEs for scheduling/precoding if the minimum correlation value is less than or equal to a threshold value.