Multi-Carrier AGC Skipping for Longer Measurement Gaps

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Solution Overview

Problem

In multi-carrier communication systems, the effective radio time during transmission gaps is often insufficient due to AGC settling time, leading to unreliable cell detection and reduced RSRP measurement accuracy, especially when there is a large difference between expected and actual signal strength.

Innovation Solution

A method is introduced where the served device performs a first AGC procedure during a transmission gap, determines a gain difference parameter based on channel conditions and elapsed time, and selects an AGC configuration or algorithm to minimize settling time, allowing the second AGC procedure to be skipped or optimized using the first gain value as a starting point, thereby extending effective radio time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If the AGC settling time is reduced to extend effective radio time, then cell detection reliability and RSRP measurement accuracy improve, but the gain control precision may deteriorate when there is a large difference between expected and actual signal strength

Engineering Contradiction:
Improveeffective radio timeVSAvoidcell detection reliability
Core Design Contradiction:
Loss of timeVSReliability

Solution Approach 1:

The patent applies preliminary action by performing a first AGC procedure during the transmission gap before cell detection and RSRP measurement. This preliminary AGC settling allows the gain to be optimized in advance, ensuring that subsequent operations benefit from stable gain settings without consuming additional time during the critical measurement phase.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent segments the AGC process into multiple distinct procedures: a first AGC procedure performed during the transmission gap to establish initial gain settings, and subsequent AGC adjustments during actual signal reception. This segmentation allows the system to prepare gain settings in advance while maintaining the ability to adapt during signal reception, effectively resolving the time-reliability contradiction.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If more bits are used to represent received signal samples to prevent information loss, then measurement accuracy improves, but memory resources and receiver complexity increase

Engineering Contradiction:
ImproveRSRP measurement accuracyVSAvoidreceiver design complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent changes the parameter of signal representation by applying AGC to scale received signals to an optimal amplitude range before digitization and processing. This parameter adjustment ensures that signals are represented with sufficient precision using standard bit depths, avoiding the need for increased bit representation while maintaining measurement accuracy through proper gain control.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2367385B1Technique for automatic gain control in a multi-carrier communication system
Publication Date: 2012.05.16 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP2367385B1 patent drawingFigure 1~2
  • EP2367385B1 patent drawingFigure 3
  • EP2367385B1 patent drawingFigure 4

AI summary

A technique for performing Automatic Gain Control (AGC) in a multi-carrier communication system in which transmission gaps are scheduled on a serving carrier to enable temporary tuning to another carrier by a served device is described. A method embodiment of this technique comprises: performing a first AGC procedure in relation to a first signal received on a first carrier during a first transmission gap; determining an AGC configuration for a second procedure based on at least one of channel conditions in relation to the first carrier and a lapsed time since the first transmission gap; and determining if the second AGC procedure can be skipped.