RF Front-End Filter Bypass for Blocker Rejection and Sensitivity
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Solution Overview
Problem
Radio frequency communication systems face insertion loss and degraded receive sensitivity due to filters used for blocker filtering, which also introduce power amplifier output power increases and coexistence issues in RF communication systems.
Innovation Solution
Implementing a front-end system with a transceiver that can dynamically change the amount of blocker filtering and bypass filters in different modes based on detected signal levels and interference conditions, using tunable filters and automatic gain control to optimize signal processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If filters are used for blocker filtering in the front-end system, then blocker rejection is improved, but receive sensitivity is degraded due to insertion loss
Solution Approach 1:
The patent implements dynamic filter bypass capability that allows the front-end system to switch between filtered and bypassed states based on real-time signal conditions. The transceiver can dynamically select to bypass the filter when blocker conditions are not present, thereby eliminating insertion loss and improving receive sensitivity, while enabling filter operation when blockers are detected to maintain blocker rejection performance.
Solution Approach 2:
The system changes the operational state parameter of the filter from 'engaged' to 'bypassed' based on detected signal conditions. This parameter change allows the system to optimize between two extreme states: full filtering for blocker rejection and full bypass for sensitivity, with the ability to transition between states as environmental conditions change.
2Object-affected harmful factors
If filters are used for blocker filtering, then blocker rejection is improved, but transmit path insertion loss increases
Solution Approach 1:
The patent extends dynamic bypass capability to the transmit path, allowing the front-end system to bypass filters during transmission when blocker conditions are not present. This dynamic control eliminates unnecessary insertion loss in the transmit path, improving power efficiency and reducing the power amplifier output power requirement while maintaining blocker rejection when needed.
3Object-affected harmful factors
If fixed blocker filtering is implemented, then blocker rejection is ensured, but system adaptability to different signal conditions is reduced
Solution Approach 1:
The system incorporates feedback mechanisms where the transceiver monitors signal conditions including blocker presence and signal strength. Based on this feedback, the system automatically adjusts the filter bypass state and gain settings to optimize performance for the current environmental conditions, thereby achieving both blocker rejection and high adaptability to varying signal scenarios.
Solution Approach 2:
The front-end system is designed with multi-functionality to handle diverse operating conditions. The filter bypass capability and variable gain control allow the same hardware to optimally perform in both blocker-rich environments (with filtering) and weak signal environments (with bypass), making the system universally adaptable to different signal conditions without requiring separate dedicated paths.
Data Source
AI summary
Apparatus and methods for filter bypass for radio frequency front-ends are provided. In certain configurations, a front-end system includes a low noise amplifier, a blocker filter, a plurality of switches configured to control connectivity of the blocker filter and the low noise amplifier in a signal path through the front-end system. The front-end system further includes a controller configured to control the plurality of switches to operate the front-end system in a selected mode chosen from a plurality of modes. The plurality of modes includes a first mode in which the blocker filter is before the low noise amplifier in the signal path, and a second mode in which the low noise amplifier is before the blocker filter in the signal path.