Intra-Band Carrier Aggregation Gain Control for Weak PCell Stability

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Solution Overview

Problem

Intra-band carrier aggregation in wireless communication networks faces challenges due to significant variations in received signal strength caused by multipath effects and local oscillator imbalances, leading to suboptimal receive processing and potential radio link failures, especially when the primary component carrier is weaker than the secondary component carrier.

Innovation Solution

The implementation of a common gain control mechanism that estimates and applies a shared gain to both primary and secondary component carriers based on their respective signal quality indicators, prioritizing the primary carrier to avoid radio link failures and optimize signal processing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If separate gain control is applied to each component carrier, then signal quality for each carrier can be optimized, but device complexity and power consumption increase

Engineering Contradiction:
Improvesignal qualityVSAvoidgain control complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines separate gain control circuits for PCell and SCell into a single common gain control mechanism. The base station determines a first gain value for the PCell and a second gain value for the SCell, then transmits both values to the UE which applies them through a unified gain control process. This merging approach maintains optimized signal quality for each carrier while reducing device complexity and power consumption by eliminating redundant separate gain control hardware and processing.

Inventive Principle:
Principle #5Merging (Combining)

2Adaptability or versatility

If the primary component carrier is weaker than the secondary component carrier, then carrier aggregation can be maintained, but radio link failures occur due to suboptimal receive processing

Engineering Contradiction:
Improvecarrier aggregation capabilityVSAvoidradio link stability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The base station performs preliminary gain determination before transmitting the aggregated carriers. It calculates the first gain value based on the PCell's reference signal received power and the second gain value based on the SCell's reference signal received power, then transmits these pre-calculated gain values to the UE. This preliminary action ensures that the UE has the correct gain settings in advance, enabling optimal receive processing even when the PCell is weaker than the SCell, thereby preventing radio link failures while maintaining carrier aggregation capability.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2918012B1Gain control for intra-band carrier aggregation
Publication Date: 2019.07.24 QUALCOMM INC
  • EP2918012B1 patent drawingFigure 1
  • EP2918012B1 patent drawingFigure 2
  • EP2918012B1 patent drawingFigure 3A~3C

AI summary

In a wireless communication system, carrier aggregation may be used to provide desired amounts of bandwidth, where a primary carrier and one or more secondary carriers are aggregated. At the receive side of a system in which the aggregated carriers are in a single frequency band, an amplifier may be used to apply a common gain to the aggregated carriers in the single frequency band, and the common gain may be determined as a function of indications of received signal quality associated with groups of aggregated carriers containing one or more of the aggregated carriers, where one group contains the primary carrier and possible one or more secondary carriers and another group contains only secondary carriers.