Beam Coordination in Massive MIMO via PBICH Indicators

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Solution Overview

Problem

In massive MIMO wireless cellular systems, existing inter-cell interference coordination methods are inefficient as they primarily address interference at the cell level rather than the user or beam level, leading to significant signal degradation due to enhanced interference from neighbor cells caused by advanced beamforming.

Innovation Solution

A method and system that utilize a Physical Beam Indicator Channel (PBICH) to transmit encoded beam indicators to users, allowing user terminals to create and report interference information, which is then used by base stations to dynamically coordinate time and/or frequency resources between interfering beams, thereby isolating only the affected beams and reducing interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional cell-level interference coordination methods are used in massive MIMO systems, then the coordination mechanism covers all users and beams, but this causes significant signal degradation because interference is enhanced by beamforming and affects only specific beams rather than the entire cell

Engineering Contradiction:

Improvesignal qualityVSAvoidsystem capacity

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent segments the interference coordination from cell-level to beam-level by introducing beam indicators that identify specific interfering beams. Instead of coordinating all resources across the entire cell, the system identifies and coordinates only the specific beams causing interference, dividing the problem into manageable beam-specific segments.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by making interference coordination beam-specific rather than cell-wide. Each beam can be coordinated independently based on its interference characteristics, allowing different coordination strategies for different beams while maintaining high system capacity elsewhere.

Inventive Principle:

Principle #3Local quality

2Reliability

If beamforming is used to enhance signal to noise ratio, then received signal quality is significantly improved, but interference from neighbor cells is also enhanced by the same factor resulting in signal degradation

Engineering Contradiction:

Improvesignal to noise ratioVSAvoidinterference from neighbor cells

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent implements feedback mechanisms where user equipment reports interference measurements and beam indicators back to the base station. This feedback loop enables the system to identify interfering beams and adjust coordination strategies dynamically, allowing the system to respond to actual interference conditions rather than using static cell-level coordination.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent introduces beam indicators as an intermediary element that mediates between the beamforming process and interference coordination. These indicators enable the system to identify specific interfering beams without requiring direct cell-level coordination, allowing precise targeting of interference sources while maintaining beamforming gains.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If cell-level resource coordination is implemented, then all time and frequency resources are coordinated between cells, but this is inefficient because interference from an aggressor cell is usually caused by only one beam or a limited set of beams

Engineering Contradiction:

Improveinterference coordination effectivenessVSAvoidresource coordination overhead

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the resource coordination problem by introducing beam indicators that identify specific interfering beams. Instead of coordinating all time and frequency resources across the entire cell, the system coordinates only the resources used by specific interfering beams, dividing the coordination task into beam-specific segments.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies partial action by implementing interference coordination only for the specific beams causing interference rather than coordinating all beams in the cell. This partial coordination approach reduces overhead and complexity while maintaining effectiveness by targeting only the problematic beams.

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS9654261B2Method and a system for beam coordination between base stations in wireless cellular systems and computer program thereof

Publication Date: 2017.05.16 TELEFONICA SA

AI summary

A method involving coordinating resources between a victim and an aggressor base station in massive MIMO systems, whereby only those specific beams involved in the interference scenario are coordinated in time and/or frequency domains without affecting other resources committed to other users as well as legacy users. Also disclosed is a system and computer program configured to implement the method.