MIMO Repeater Orthogonal Polarization Signal Restoration

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Solution Overview

Problem

Traditional repeaters fail to maintain multiple in/multiple out (MIMO) benefits in networks due to the 'keyhole effect' when using a single donor antenna and lose MIMO benefits even with dual repeaters if there's a clear line of sight, requiring high signal-to-noise ratios or scattering for effective signal paths.

Innovation Solution

Employing two orthogonally polarized antennas at the base station and dual repeaters with a mechanism to restore orthogonality and lower the condition number of MIMO signals, using digital signal processing and field programmable gate arrays to compute and correct transmission matrices, and optimizing antenna pointing based on signal quality measurements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single donor antenna is used in a repeater, then the device complexity is reduced, but the MIMO benefits are lost due to the keyhole effect

Engineering Contradiction:

Improverepeater structureVSAvoidMIMO signal transmission

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The single donor antenna is segmented into two orthogonally polarized donor antennas, allowing the repeater to maintain two independent signal paths for MIMO transmission while keeping the overall repeater structure relatively simple

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces polarization dimension to the antenna system by using two orthogonally polarized donor antennas, transforming a single-antenna SISO system into a dual-path MIMO system without significantly increasing spatial complexity

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Reliability

If dual repeaters with two donor antennas are used, then MIMO benefits can be maintained, but the device complexity increases

Engineering Contradiction:

ImproveMIMO signal transmissionVSAvoidrepeater structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the functions of two separate repeaters into a single dual-antenna repeater unit, combining the signal processing and transmission capabilities in one device while maintaining MIMO benefits

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The dual-antenna repeater is designed to perform multiple functions: receiving signals from a single donor antenna, separating them into two orthogonal polarizations, and transmitting them as two independent MIMO streams, making it a universal solution for MIMO repetition

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If two paths are maintained through scattering, then MIMO benefits are preserved, but the signal-to-noise ratio requirement increases

Engineering Contradiction:

ImproveMIMO signal transmissionVSAvoidsignal-to-noise ratio

Core Design Contradiction:

ReliabilityVSPower

Solution Approach 1:

The patent changes the propagation parameter from scattered paths to orthogonally polarized direct paths, maintaining two independent signal paths while improving signal quality and reducing SNR requirements through the orthogonality property

Inventive Principle:

Principle #35Parameter changes

4Measurement precision

If orthogonality restoration mechanism is added, then MIMO signal quality is improved, but the device complexity increases

Engineering Contradiction:

Improvesignal orthogonalityVSAvoidsignal processing mechanism

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent implements a feedback mechanism where the orthogonality of the received signals is measured and used to adjust the transmission matrix, continuously maintaining optimal orthogonality despite channel variations

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent replaces complex mechanical or hardware-based orthogonality restoration mechanisms with digital signal processing using FPGAs, computing the transmission matrix digitally to restore orthogonality with minimal additional hardware

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS8731461B2Repeater for MIMO signals in a network

Publication Date: 2014.05.20 CELLULAR SPECIALTIES

AI summary

A system to repeat MIMO signals in a network by orthogonally polarizing the signals and maintaining the orthogonal polarization.