Adaptive Filter Branch Sharing for Faster MIMO DPD Convergence

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Solution Overview

Problem

Massive Multiple-Input-Multiple-Output (MIMO) systems with numerous antennae face challenges in computation load, resource utilization, and convergence speed due to the complexity of digital pre-distortion (DPD) algorithms in RF circuit compensation.

Innovation Solution

A method is proposed where gradient-based information is shared among all branches of the adaptive filter system, allowing uninterrupted parameter updates based on similarity between branches, using algorithms like LMS, NLMS, SGD, RLS, or SPSA, to accelerate convergence and reduce computation load.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the number of antennae is increased in massive MIMO systems, then beamforming capability is improved, but computation load and complexity of DPD algorithms increase significantly

Engineering Contradiction:
Improvebeamforming capabilityVSAvoidcomputation load
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the DPD algorithm into multiple parallel branches, each handling a subset of antennae. This segmentation allows the system to manage massive MIMO configurations by dividing the overall computation into smaller, more manageable tasks that can be processed simultaneously, thereby reducing the computational burden on individual processing units while maintaining the enhanced beamforming capability provided by the large number of antennae.

Inventive Principle:
Principle #1Segmentation

2Productivity

If the number of parallel branches in adaptive filter system is increased, then resource utilization is improved, but convergence speed decreases

Engineering Contradiction:
Improveresource utilizationVSAvoidconvergence speed
Core Design Contradiction:
ProductivityVSSpeed

Solution Approach 1:

The patent implements a feedback mechanism where gradient-based information is transferred and shared among all parallel branches of the adaptive filter system. This feedback loop allows each branch to benefit from the learning progress of other branches, enabling faster convergence despite the increased number of parallel processing units. The gradient information exchange ensures that all branches converge toward the optimal solution more efficiently than if they operated independently.

Inventive Principle:
Principle #23Feedback

3Speed

If gradient-based information is shared among all branches, then convergence speed is improved, but communication overhead increases

Engineering Contradiction:
Improveconvergence speedVSAvoidcommunication overhead
Core Design Contradiction:
SpeedVSLoss of information

Solution Approach 1:

The patent extracts only the essential gradient-based information needed for parameter updates and transfers it among the parallel branches. By taking out only the critical gradient data rather than sharing all intermediate computations or raw data, the system achieves faster convergence while minimizing the communication overhead and information loss associated with data exchange between branches.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentUS11817921B2System and method for adaptive filtering
Publication Date: 2023.11.14 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • US11817921B2 patent drawing
  • US11817921B2 patent drawing
  • US11817921B2 patent drawing

AI summary

A method in an adaptive filter system is provided. The method comprises obtaining parameters for a plurality of branches of the adaptive filter system. The method further comprises computing gradient-based information for a selected one of the plurality of branches. The method further comprises updating the parameters for the plurality of branches based on the gradient-based information for the selected branch. An adaptive filter system is also provided.