Anticipatory Receiver Switching for Multipath Signal Quality

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Solution Overview

Problem

Radio communication systems in multipath environments face challenges with reception errors due to interference and noise, as existing diversity techniques fail to accurately evaluate communication quality, leading to unpredictable errors with higher M-ary modulation methods.

Innovation Solution

A system and method that estimate signal quality metrics for baseband signals from multiple receivers, comparing these metrics to thresholds to switch between receivers and ensure error-free data transmission by converting constant bit rate signals to baseband signals and using a signal quality estimation circuit with a distance calculator, average calculator, and comparator to generate alerts and trigger switching.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If M-ary modulation methods with larger values (e.g., 16 QAM) are employed to increase data transmission speed, then communication speed is improved, but the system becomes more susceptible to reception errors in multipath environments

Engineering Contradiction:

Improvedata transmission speedVSAvoidreception error rate

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent performs preliminary signal quality estimation and receiver evaluation before actual data transmission. The system pre-assesses the capability of multiple receivers to handle M-ary modulation signals under current channel conditions, and selects the most suitable receiver in advance, thereby preventing reception errors before they occur

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent dynamically adapts the modulation scheme and receiver selection based on real-time channel conditions. The system continuously monitors signal quality metrics and adjusts the M-ary modulation order and receiver assignment accordingly, transitioning between different operating states to optimize both speed and reliability

Inventive Principle:

Principle #15Dynamics

2Reliability

If conventional diversity techniques (1+1 Frequency Diversity or 1+1 Space Diversity) are used to protect against multipath interference, then signal path protection is improved, but the system cannot accurately evaluate communication quality leading to unpredictable errors

Engineering Contradiction:

Improvesignal path protectionVSAvoidcommunication quality evaluation accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The patent replaces conventional mechanical switching-based diversity techniques with an intelligent signal processing system. Instead of physically switching between frequency or spatial paths, the system uses digital signal processing to estimate signal quality metrics and selectively process signals through virtual channel paths, achieving more precise quality evaluation

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent implements a feedback mechanism where signal quality metrics are continuously estimated from received signals and used to adjust receiver selection and processing parameters. The system monitors reception quality in real-time and feeds this information back to the controller, which adjusts the reception strategy accordingly to maintain optimal performance

Inventive Principle:

Principle #23Feedback

3Reliability

If multiple receivers are deployed to handle signal path disturbances, then system reliability is improved, but device complexity increases

Engineering Contradiction:

Improvedata transmission reliabilityVSAvoidreceiver system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent designs a universal receiver architecture that can handle multiple modulation schemes and signal conditions through a single integrated processing path. The receiver includes universal components such as FFT processors, channel estimators, and equalizers that can process different M-ary modulation signals (4-QAM, 16-QAM, 64-QAM, etc.) using the same fundamental processing steps, thereby reducing overall system complexity

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent changes processing parameters rather than physical architecture to adapt to different signal conditions. By adjusting parameters such as FFT size, channel estimation coefficients, and equalization tap lengths, the system can optimize performance for different modulation schemes and channel conditions without requiring separate hardware configurations for each scenario

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS8687737B2System and method for anticipatory receiver switching based on signal quality estimation

Publication Date: 2014.04.01 AVIAT U S

AI summary

In various embodiments, a first and second complex multiplier may be configured to receive an input signal and provide a baseband I component signal and a baseband Q component signal, respectively. A first and second filter may be configured to filter the baseband I component signal and the baseband Q component signal, respectively. An equalizer may be configured to equalize the filtered baseband I component signal and the filtered baseband Q component signal. A carrier recovery portion may be configured to generate a reference signal based on the equalized filtered baseband I component signal and the equalized filtered baseband Q component signal. A first and second multilevel comparator may be configured to receive the equalized filtered baseband I component signal from the carrier recovery portion and provide an output I and receive the equalized filtered baseband Q component signal and provide an output Q signal for further modulation.