Adaptive Beam Pattern Weight Selection for Multi-User MIMO Interference

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Solution Overview

Problem

Fixed multi-beam antenna systems face challenges in achieving good spatial isolation between beams due to high side lobe levels, which leads to interference issues in multi-user MIMO systems, resulting in reduced aperture efficiency and poor power amplifier utilization.

Innovation Solution

The method involves generating multiple sets of weights for each fixed beam to maintain low side lobe levels only in specific directions, allowing for adaptive beam pattern adjustment based on scheduling decisions to minimize interference between beams, thereby improving spatial isolation and signal interference ratio.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If low side lobe levels are enforced in all directions for each fixed beam, then spatial isolation between beams is improved, but aperture efficiency is reduced

Engineering Contradiction:
Improveside lobe interferenceVSAvoidaperture efficiency
Core Design Contradiction:
Object-affected harmful factorsVSProductivity

Solution Approach 1:

The patent applies local quality by generating different weight sets for different directional regions. Each weight set is optimized to provide low side lobe levels only in specific directions where other beams have their main lobes, rather than uniformly suppressing side lobes in all directions. This allows the antenna aperture to maintain high efficiency while providing targeted interference suppression where needed.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent implements dynamics by making the beam patterns adaptive rather than fixed. The system dynamically selects appropriate weight sets from multiple pre-generated options based on real-time scheduling decisions and spatial relationships between active beams. This allows the side lobe suppression characteristics to change adaptively according to the current operational context.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If multiple weight sets are generated and stored for each fixed beam, then adaptability for minimizing interference is improved, but device complexity increases

Engineering Contradiction:
Improvebeam pattern adaptabilityVSAvoidweight set storage and selection
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by pre-generating and storing multiple weight sets for each fixed beam before operation. Each weight set is pre-optimized for specific directional scenarios. During operation, the system simply needs to select the appropriate pre-computed weight set based on current beam scheduling, avoiding the need for real-time complex optimization calculations.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent utilizes parameter changes by varying the weight parameters of antenna elements to create different beam patterns. By changing these weights according to pre-computed sets, the system can adapt beam characteristics to match different spatial configurations and interference scenarios without changing the physical antenna structure.

Inventive Principle:
Principle #35Parameter changes

3Object-generated harmful factors

If side lobe levels are suppressed in all directions, then interference to other beams is reduced, but power amplifier utilization deteriorates

Engineering Contradiction:
Improvebeam interferenceVSAvoidpower amplifier utilization
Core Design Contradiction:
Object-generated harmful factorsVSUse of energy by moving object

Solution Approach 1:

The patent applies local quality by suppressing side lobe levels only in specific directions where other beams operate, rather than uniformly across all directions. This targeted approach reduces interference to other beams while maintaining higher power amplifier utilization by avoiding unnecessary suppression in directions where no other beams are active.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3266118B1A method, control system and communication system for adapting beam patterns
Publication Date: 2019.02.13 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3266118B1 patent drawingFigure 1~3
  • EP3266118B1 patent drawingFigure 4a~4b
  • EP3266118B1 patent drawingFigure 5a~5b

AI summary

The present invention relates to a method and control system for adapting beam patterns generated by at least one array antenna 21-23 serving one or more users UE1, UE2. Each array antenna comprising multiple antenna subarrays 24 within an aperture and is configured to provide coverage to a service area using a set of fixed beams 41, each fixed beam having a beam pattern covering a portion of the service area which beam pattern is generated by applying weights to the antenna subarrays. The method comprises: generating 116 several sets of weights for each fixed beam, wherein each set of weights generates similar coverage in a main direction and side lobe levels lower than one or more thresholds in other directions; storing 118 the sets of weights for each fixed beam; receiving 120 information from a scheduler 34; 91 regarding at least two fixed beams, wherein a first fixed beam 25; 96 and a second fixed beam 26; 94 provides coverage to the one or more users UE1, UE2; selecting 121 a set of weights for the first fixed beam 25; 96 based on the side lobe levels 95 in the main direction of the second fixed beam 94, and a set of weights for the second fixed beam 26; 94 based on the side lobe levels 97 in the main direction of the first fixed beam 96 to minimize interference between the first and second beams, and applying 122 the selected set of weights for each fixed beam to the antenna subarrays when generating the respective beam pattern.