Distributed MIMO Scheduling for Access Point Clusters

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Solution Overview

Problem

In wireless communication systems, especially those employing multiple-input multiple-output (MIMO) technology, there is a need for effective techniques to manage interference between devices sharing the same communication resource, particularly in scenarios with unplanned or unmanaged access point deployments where central control is absent.

Innovation Solution

The implementation of a distributed MIMO communication system that identifies and schedules wireless nodes within a cluster, using coordinated beamforming to mitigate interference by grouping underutilized access points and forming nulls to reduce interference between devices, thereby optimizing resource usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multiple devices transmit on a shared communication resource, then resource utilization is improved, but interference between devices increases

Engineering Contradiction:

Improveresource utilizationVSAvoidinterference

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The communication resource is segmented into different time slots, frequency channels, and spatial beams. Devices are assigned to different segments to transmit simultaneously, allowing high resource utilization while maintaining low interference through orthogonal separation in multiple domains

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A central coordinator or distributed scheduling algorithm acts as an intermediary to manage resource allocation. The scheduler assigns time-frequency-spatial resources to different devices, ensuring that transmissions are coordinated to minimize interference while maximizing overall resource utilization

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If beamforming is used to directionalize transmissions, then signal focus is improved, but interference to other devices on the same resource remains

Engineering Contradiction:

Improvesignal focusVSAvoidinterference

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system transitions from two-dimensional beamforming (angular space) to multi-dimensional resource allocation by adding time and frequency dimensions. This allows simultaneous transmissions in the same angular direction at different time-frequency resources, maintaining signal focus while eliminating interference through orthogonal separation in additional dimensions

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Ease of operation

If a central controller manages the network, then coordination is improved, but system complexity and deployment difficulty increase

Engineering Contradiction:

ImprovecoordinationVSAvoiddeployment complexity

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

Access points and devices autonomously perform scheduling decisions using distributed algorithms. Each node exchanges local channel state information and independently determines resource allocation, eliminating the need for a central controller while maintaining effective coordination through decentralized intelligent decision-making

Inventive Principle:

Principle #25Self-service

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach enhances communication efficiency by minimizing interference and optimizing resource usage, leading to improved throughput and reliability in wireless communication systems, even in dense and unmanaged network environments.

Implementation Method 1

using coordinated beamforming to mitigate interference by grouping underutilized access points and forming nulls to reduce interference between devices

Methodology Applied

Scientific EffectBeamforming:

Implementation Method 2

grouping underutilized access points and forming nulls to reduce interference between devices

Methodology Applied

Scientific EffectNull formation:

Data Source

PatentUS11570788B2Distributed MIMO communication scheduling in an access point cluster

Publication Date: 2023.01.31 QUALCOMM INC

AI summary

Various aspects of the disclosure relate to distributed multiple-input multiple-output (MIMO) communication such as coordinated beamforming or Joint MIMO. In some aspects, distributed MIMO is used to support communication in a cluster of wireless nodes (e.g., access points). A distributed MIMO scheduling scheme as taught herein is used to schedule the wireless nodes (e.g., access points and/or stations) operating within the cluster. For example, stations may be scheduled across basis services sets of the access points for a downlink transmission and/or an uplink transmission.