Receiver Gain Control Using Carrier-Frequency Thresholds

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Solution Overview

Problem

Conventional Automatic Gain Control (AGC) algorithms in radio receivers are inefficient due to the need for time-consuming power measurements and unnecessary power consumption, especially when only a portion of the transmission bandwidth is received, leading to prolonged radio activity and reduced battery life in mobile devices.

Innovation Solution

Implementing a gain control system that assesses the frequency difference between current and target carrier frequencies to determine whether to use a full or optimized AGC algorithm, leveraging historical gain variability data and metrics like signal-to-noise ratio to adjust amplifier gain settings efficiently.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a full automatic gain control algorithm is performed to ensure accurate gain settings, then receiver reliability is improved, but time consumption and power consumption increase

Engineering Contradiction:
Improvereceiver reliabilityVSAvoidtime consumption
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent changes the parameter of AGC algorithm complexity based on frequency difference conditions. When frequency difference exceeds a threshold, a simplified AGC algorithm is used; when within threshold, a more accurate algorithm is applied. This dynamic parameter adjustment resolves the contradiction by adapting algorithm precision to actual operational needs.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements dynamic selection between different AGC algorithm modes based on real-time frequency difference measurements. The system transitions between simplified and full AGC algorithms dynamically, rather than using a fixed approach, thereby optimizing both time consumption and reliability according to current operating conditions.

Inventive Principle:
Principle #15Dynamics

2Reliability

If a full automatic gain control algorithm is performed to ensure accurate gain settings, then receiver reliability is improved, but power consumption increases

Engineering Contradiction:
Improvereceiver reliabilityVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent adjusts the operational parameter of AGC algorithm selection based on frequency difference. By changing from full AGC to simplified AGC when frequency difference is large, power consumption is reduced while maintaining sufficient reliability for the given conditions.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies partial AGC action (simplified algorithm) when full AGC is not necessary. When frequency difference exceeds the threshold, the simplified algorithm provides sufficient gain control without the excessive power consumption of the full algorithm, achieving adequate reliability with reduced energy use.

Inventive Principle:
Principle #16Partial or excessive action

3Measurement precision

If power measurements are performed during all subframes to improve measurement accuracy, then measurement precision is improved, but time consumption increases

Engineering Contradiction:
Improvepower measurement precisionVSAvoidtime consumption
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent applies different measurement strategies to different subframe types. MBSFN subframes are handled differently from regular subframes, with measurements performed only when appropriate. This local differentiation improves overall measurement precision while reducing unnecessary time consumption from redundant measurements.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent performs power measurements only partially - specifically during suitable subframes rather than all subframes. When frequency difference is within threshold, measurements are performed during appropriate subframes; when exceeded, measurements may be skipped or reduced, achieving sufficient precision with less time investment.

Inventive Principle:
Principle #16Partial or excessive action

4Manufacturing precision

If the radio remains active longer to perform complete AGC procedures, then gain control accuracy is improved, but battery life is reduced

Engineering Contradiction:
Improvegain control accuracyVSAvoidbattery life
Core Design Contradiction:
Manufacturing precisionVSDuration of action of stationary object

Solution Approach 1:

The patent changes the operational parameter of AGC procedure completeness based on frequency difference conditions. By adjusting between simplified and full AGC modes, the system achieves sufficient gain control accuracy while minimizing radio active time, thereby extending battery life.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies partial AGC procedures (simplified algorithm) when frequency difference exceeds threshold, reducing the time the radio must remain active. This partial action provides adequate gain control for the given conditions while significantly reducing battery consumption compared to always performing complete AGC procedures.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP3284172B1Optimization of automatic gain control for narrow bandwidth operation
Publication Date: 2020.07.22 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3284172B1 patent drawingFigure 1
  • EP3284172B1 patent drawingFigure 2
  • EP3284172B1 patent drawingFigure 3a~3c

AI summary

The gain of an amplifier in a receiver operating in a cellular communication system is controlled by determining one or more gain variability metrics, which are then used to produce first and second threshold values. A frequency difference between a current carrier frequency and a target carrier frequency is ascertained and then compared to the threshold values. Target gain setting production is based on comparison results: If the frequency difference is larger than the first threshold, a full automatic gain control algorithm is performed; if the frequency difference is smaller than the first threshold and larger than the second threshold, an optimized automatic gain control algorithm is performed, wherein the optimized automatic gain control algorithm uses a current gain setting as a starting point; and if the frequency difference is smaller than both the first and second thresholds, the current gain setting is used as the target gain setting.