Isolating Down-Conversion Mixer for Carrier Aggregation Desensing

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Solution Overview

Problem

Carrier aggregation in wireless communication systems leads to interference between multiple frequency bands, degrading signal quality due to cross-routed transmission lines and interference between different carriers, which existing technologies struggle to effectively mitigate.

Innovation Solution

Incorporating an isolating down-conversion mixer with a buffer stage and shunt capacitor for filtering, which can be enabled or disabled based on carrier aggregation configuration, to improve isolation between transmission paths and reduce desensing effects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If carrier aggregation is implemented to enable simultaneous operation on multiple frequency bands, then the productivity and versatility of the wireless communication system is improved, but interference between transmission paths and signal quality deteriorate

Engineering Contradiction:

Improvesimultaneous operation on multiple carriersVSAvoidinterference between transmission paths

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

An isolating buffer is introduced as an intermediary component between the transmission line and the down-conversion mixer. This buffer acts as a mediator that blocks interference signals from coupling between different transmission paths while allowing desired signals to pass through, thereby resolving the contradiction between maintaining signal quality and enabling carrier aggregation operation

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The receiver signal path is segmented into separate isolated sections using the buffer, creating distinct isolation zones for different frequency bands. This segmentation prevents interference coupling between carrier aggregation paths by dividing the previously coupled transmission environment into isolated segments

Inventive Principle:

Principle #1Segmentation

2Reliability

If isolating buffers are added to reduce interference between transmission paths, then signal quality and isolation are improved, but device complexity increases

Engineering Contradiction:

Improveisolation between transmission pathsVSAvoidnumber of buffer components

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Instead of implementing isolation throughout the entire receiver system, the isolating buffer is applied locally at the critical interface between the transmission line and the down-conversion mixer. This localized approach provides the necessary isolation precisely where interference coupling occurs most severely, achieving high reliability without unnecessarily increasing overall device complexity

Inventive Principle:

Principle #3Local quality

3Object-affected harmful factors

If isolating buffers are enabled for carrier aggregation operation, then interference is reduced, but power consumption increases

Engineering Contradiction:

Improveinterference between carriersVSAvoidpower consumption of buffers

Core Design Contradiction:

Object-affected harmful factorsVSUse of energy by moving object

Solution Approach 1:

The isolating buffer is implemented with dynamic control capability, allowing it to be enabled or disabled based on the operational mode. The buffer is activated specifically during carrier aggregation operation when interference reduction is needed, and can be deactivated or placed in low-power state during single-carrier operation, thereby dynamically adapting power consumption to actual operational requirements

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The buffer operation is controlled periodically or conditionally based on carrier aggregation configuration states. Rather than continuous operation, the buffer is activated only during periods when carrier aggregation is in use and interference mitigation is required, reducing overall power consumption while maintaining effectiveness during critical operation periods

Inventive Principle:

Principle #19Periodic action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution significantly reduces interference between transmission paths, enhancing signal quality and enabling efficient simultaneous operation on multiple carriers by actively managing the isolating buffers in response to carrier aggregation configurations.

Implementation Method 1

shunt capacitor filtering may be used to reduce interference between multiple frequency bands

Methodology Applied

Scientific EffectCapacitive coupling: Capacitance

Data Source

PatentUS11728838B2Isolating down-conversion mixer for a radio frequency (RF) transceiver

Publication Date: 2023.08.15 QUALCOMM INC

AI summary

Carrier aggregation (CA) may cause interference between operation on two or more carriers within a user equipment (UE). This interference can degrade signal quality on one or more of the carriers involved in the carrier aggregation, which may be referred to as “desensing” one or more carriers. One or more isolating buffers may be coupled at a down-conversion mixer at a point where the down-conversion mixer receives a signal from a transmission line for isolating the transmission line from other transmission lines. The isolating buffer may reduce the effect of interference between multiple transmission lines carrying different carriers during carrier aggregation (CA) operation. The isolating buffers may be used in an RF transceiver supporting both 5G sub-7 GHz and 5G mmWave wireless networks and carrier aggregation across sub-7 GHz and mmWave bands.