MIMO LO Sharing via IF Cables for Phase Noise Synchronization

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Solution Overview

Problem

In MIMO microwave point-to-point communication networks, differential phase noise between multiple transmitters and receivers is exacerbated by the use of high-frequency signals, making it costly and inefficient to synchronize local oscillators across outdoor units, leading to signal loss and decreased output power.

Innovation Solution

The implementation of a system that shares low-frequency connections via intermediate frequency cables between indoor and outdoor units to synchronize local oscillators using phase-locked loops, allowing for effective phase noise reduction and synchronization without the need for expensive high-frequency cables.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If high-frequency signals are used in MIMO microwave communication networks, then data flow and bandwidth are improved, but differential phase noise between multiple transmitters and receivers is exacerbated

Engineering Contradiction:

Improvedata flowVSAvoidphase noise

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent introduces an intermediary mechanism (phase synchronization system) that mediates between the high-frequency signals and the local oscillators. This intermediary synchronizes the phase of local oscillators across multiple outdoor units, effectively reducing differential phase noise while maintaining the benefits of high-frequency operation for data transmission

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If local oscillators are synchronized across outdoor units using high-frequency cables, then phase noise is reduced, but cost and signal loss increase

Engineering Contradiction:

ImprovesynchronizationVSAvoidsignal loss

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent changes the frequency parameter of the connection cables from high-frequency to low-frequency. By using low-frequency cables to connect outdoor units to the indoor unit, the system achieves effective phase noise reduction and synchronization while minimizing signal loss and avoiding the need for expensive high-frequency cables

Inventive Principle:

Principle #35Parameter changes

3Reliability

If local oscillators are synchronized across outdoor units, then phase noise is reduced, but system cost increases

Engineering Contradiction:

ImprovesynchronizationVSAvoidcost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent changes the frequency parameter from high-frequency to low-frequency for the connection cables, which dramatically reduces system cost. Low-frequency cables are significantly cheaper than high-frequency cables while still achieving the required synchronization performance for phase noise reduction

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs inexpensive low-frequency cables instead of expensive high-frequency cables to achieve synchronization. This substitution with cheaper components reduces the overall system cost while maintaining the necessary functional performance for phase noise mitigation

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

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 reduces phase noise and maintains synchronization between local oscillators, enhancing the quality and capacity of MIMO microwave communications while minimizing costs and signal loss.

Implementation Method 1

synchronize local oscillators using phase-locked loops

Methodology Applied

Scientific EffectPhase-locked loop:

Data Source

PatentUS9407271B2MIMO LO sharing in microwave point-to-point systems

Publication Date: 2016.08.02 MAXLINEAR ASIA SINGAPORE PTE LTD

AI summary

A method and system is provided for sharing of bandwidth on intermediate frequency cabling connections between indoor and outdoor units of a MIMO microwave communications system. Phase locked loop design assists in creating synchronization signals to be transmitted over the cable connecting the indoor units and outdoor units.