Radio Receiver Gain Control for Frequency-Hopping Signals

Solution Overview

Problem

Conventional automatic gain control (AGC) systems in LTE radio receivers experience delays in adjusting to changing signal strengths due to frequency hopping, leading to sub-optimal gain application and potential demodulation errors, especially in scenarios with varying environmental conditions.

Innovation Solution

A method that stores gains for previously received signals based on frequency and time, allowing for immediate application of an estimated optimal gain to new signals using a combination of stored gains, minimizing the risk of demodulation errors and data loss by reducing the initial adjustment period and accounting for environmental changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional automatic gain control systems are used in LTE radio receivers, then the system structure remains simple, but delays occur in adjusting to changing signal strengths due to frequency hopping, leading to sub-optimal gain application and potential demodulation errors

Engineering Contradiction:

Improvegain application accuracyVSAvoidadjustment delay

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The system pre-calculates and stores expected gain values for different frequency positions before frequency hopping occurs. When a frequency hop happens, the receiver can immediately apply the pre-determined gain value for the new frequency position without waiting for feedback-based adjustment, thereby eliminating adjustment delays while maintaining accurate gain application.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The gain control system transitions from a static feedback-based approach to a dynamic predictive approach that adapts to frequency hopping patterns. By continuously updating expected gain values based on stored historical data and current frequency position, the system dynamically adjusts gains in real-time without the latency inherent in conventional feedback loops.

Inventive Principle:

Principle #15Dynamics

2Reliability

If conventional automatic gain control systems are used, then the device complexity remains low, but demodulation errors occur due to inappropriate gain application during frequency hopping

Engineering Contradiction:

Improvedemodulation accuracyVSAvoidgain control mechanism

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The system pre-calculates and stores expected gain values for different frequency positions before frequency hopping occurs. When a frequency hop happens, the receiver can immediately apply the pre-determined gain value for the new frequency position without waiting for feedback-based adjustment, thereby eliminating adjustment delays while maintaining accurate gain application.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system creates a lookup table or memory structure that stores historical gain values corresponding to different frequency positions. Instead of recalculating gains in real-time through complex feedback loops, the system copies the appropriate pre-stored gain value based on the current frequency position, simplifying the control mechanism while improving reliability.

Inventive Principle:

Principle #26Copying

3Speed

If immediate gain adjustment is implemented without using stored gains, then the response speed increases, but the gain may be inappropriate due to environmental changes, increasing demodulation errors

Engineering Contradiction:

Improvegain adjustment speedVSAvoidgain accuracy

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The system pre-calculates and stores expected gain values for different frequency positions before frequency hopping occurs. When a frequency hop happens, the receiver can immediately apply the pre-determined gain value for the new frequency position without waiting for feedback-based adjustment, thereby eliminating adjustment delays while maintaining accurate gain application.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system incorporates feedback mechanisms that continuously update the stored gain values based on actual signal conditions. This feedback loop allows the system to learn from environmental changes and adjust the pre-stored gain values accordingly, ensuring that immediate gain adjustments remain accurate even as conditions change over time.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS11476818B2Automatic gain control

Publication Date: 2022.10.18 NORDIC SEMICONDUCTOR

AI summary

A method of operating a radio receiver device comprises receiving a plurality of signals with a plurality of corresponding frequencies; applying respective gains to each of the plurality of signals; and storing the gain applied to each signal and its corresponding frequency. The method comprises subsequently receiving a further signal with a further frequency; and applying a further gain to the further signal. The further gain is determined using at least one of the stored gains according to a difference between the further frequency and at least one of the plurality of corresponding frequencies.