Managing Unit AP Prediction for D-MIMO Fronthaul Load Reduction

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Solution Overview

Problem

The fronthaul capacity constraint in Distributed Massive MIMO (D-MIMO) systems limits the sharing of antenna signals and channel measurements between Access Points (APs) and the Central Processing Unit (CPU), making fast AP switching infeasible due to the need for large amounts of channel state information and additional communication delays.

Innovation Solution

A managing unit predicts a serving AP among a subset of APs using a trained model based on radio signal measurements, indicating only the predicted AP to forward UE signals to the CPU via the fronthaul, reducing unnecessary signal forwarding and measurement exchanges.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If all APs forward antenna signals to the CPU for centralized processing, then signal processing accuracy is improved, but fronthaul capacity is exceeded

Engineering Contradiction:

Improvesignal processing accuracyVSAvoidfronthaul capacity

Core Design Contradiction:

Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent extracts only the essential data elements (channel measurements and selected antenna signals) from the complete set of antenna signals, forwarding only these extracted elements to the CPU through the fronthaul connection, thereby reducing fronthaul load while maintaining processing accuracy

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent segments the signal processing function into two parts: local preprocessing at the AP (filtering and selection of antenna signals) and centralized processing at the CPU (final signal combination and decoding), allowing the system to maintain accuracy while reducing fronthaul requirements

Inventive Principle:

Principle #1Segmentation

2Measurement precision

If channel measurements are shared between all APs and CPU, then AP selection accuracy is improved, but communication delay increases

Engineering Contradiction:

ImproveAP selection accuracyVSAvoidcommunication delay

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent performs preliminary channel measurements and signal quality assessments at each AP before the selection decision is made, so that when AP selection is required, the decision can be made quickly based on pre-computed metrics, reducing communication delay while maintaining selection accuracy

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent introduces a managing unit that acts as an intermediary, maintaining local channel state information and making AP selection decisions based on pre-shared channel measurements, thereby avoiding the need for real-time measurement sharing and reducing communication delay

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS20250310871A1Managing unit and method in a communications network

Publication Date: 2025.10.02 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

A method performed by a managing unit is provided. The method is for predicting a serving Access Point, AP, among one or more APs comprised in a subset of APs, to serve a User Equipment UE in a communications network. The UE is within a radio range of the one or more APs in the subset of APs. The managing unit obtains (302) a model associated to the subset of APs, for predicting the serving AP. The model is obtained based on training the model over a first training period. The managing unit obtains (303) a predicted AP from the subset of APs to serve the UE. The predicted AP is obtained based on invoking the model with INPUT data for prediction. The INPUT data for prediction comprises radio signal measurements from a set of reporting APs comprised in the subset of APs. The managing unit communicates (304) a first indication to at least the predicted AP. The first indication indicates the AP that is predicted to serve the UE, and that only the predicted AP shall forward signals received from the UE to a Central Processing Unit, CPU, via a fronthaul.