Multi-Stage Carrier Aggregation Circuit for Close RF Bands
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Solution Overview
Problem
Carrier aggregation in RF applications, particularly in cellular LTE systems, faces challenges in simultaneously processing signals from different frequency bands like mid low band, mid band, and high band, due to difficulties in maintaining low noise figures and sufficient frequency separation, especially when bands are close in frequency.
Innovation Solution
A carrier aggregation circuit with multiple stages that combines signals from different frequency bands using phase shifting and switch circuits, allowing for carrier aggregation operations across multiple bands while supporting non-carrier aggregation operations, and includes a control circuit to manage these operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If signals from multiple frequency bands are combined in a single stage, then device complexity is reduced, but it becomes difficult to maintain low noise figures and sufficient frequency separation when bands are close in frequency
Solution Approach 1:
The patent divides the signal combining process into multiple stages: a first combining stage that aggregates signals from first and second bands, and a second combining stage that aggregates the first aggregated signal with a third band signal. This segmentation allows each stage to handle specific band combinations, maintaining proper frequency separation and noise figure performance while enabling support for multiple band aggregation scenarios.
2Reliability
If a multi-stage filter combining circuit is used to maintain low noise figures and frequency separation, then signal processing quality is improved, but device complexity increases
Solution Approach 1:
The patent implements a two-stage combining architecture where the first combining stage processes signals from first and second bands, and the second combining stage processes the aggregated signal with the third band signal. This segmentation enables quality signal processing while managing complexity through modular design.
Solution Approach 2:
The combining stages are designed to handle multiple scenarios: they can process individual bands separately, aggregate two bands together, or aggregate all three bands through the two-stage process. This multi-functionality allows the same hardware structure to adapt to different carrier aggregation configurations, reducing overall system complexity.
3Productivity
If carrier aggregation is implemented across multiple bands, then data rate capability is improved, but maintaining low noise figures becomes difficult when bands are close in frequency
Solution Approach 1:
The patent segments the carrier aggregation process into multiple combining stages, allowing signals from different frequency bands to be processed with appropriate filtering and separation at each stage. This enables high data rate capability through multi-band aggregation while maintaining low noise figures through proper signal isolation.
Data Source
AI summary
Carrier aggregation circuit having multi-stage filter combination. In some embodiments, a carrier aggregation circuit can include a first combining stage configured to aggregate a first signal in a first path associated with a first band and a second signal in a second path associated with a second band to provide a first aggregated signal in a first combined path. The carrier aggregation circuit can further include a second combining stage configured to aggregate the first aggregated signal in the first combined path and a third signal in a third path associated with a third band to provide a second aggregated signal in a second combined path.