Multiple Antenna Feed Switching for TDD Filter Bypass Sensitivity
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Solution Overview
Problem
In RF front ends, the existing designs face challenges in improving signal-to-noise ratio (SNR) and sensitivity due to impedance issues when implementing time division duplexing (TDD) filter bypassing in receive carrier aggregation configurations, which affects the performance of both primary and secondary cell communication links.
Innovation Solution
The proposed solution involves an RF front end design with multiple antenna feeds and switching devices that allow for selective bypassing of band filters during TDD reception, optimizing the configuration to avoid impedance issues and enhance sensitivity, particularly for the primary cell receive chain, while maintaining performance across multiple carrier aggregation modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If band filters are used in the receive chain, then signal filtering and interference rejection are improved, but sensitivity and signal-to-noise ratio deteriorate due to impedance issues
Solution Approach 1:
The patent implements dynamic switching between filter bypass and filter insertion modes based on the operational state (TDD reception vs. other modes). The switching device dynamically reconfigures the signal path to bypass the band filter during TDD reception to improve sensitivity, while enabling filter insertion in other modes for interference rejection, thus resolving the contradiction between these two requirements.
Solution Approach 2:
The patent changes the impedance parameter of the receive chain by switching between different configurations. In TDD reception mode, the filter bypass configuration presents a first impedance value optimized for sensitivity, while in other modes, the filter insertion configuration presents a second impedance value optimized for filtering performance, thereby resolving the impedance-related sensitivity degradation.
2Reliability
If band filters are bypassed to improve sensitivity, then signal-to-noise ratio is improved, but interference rejection capability deteriorates
Solution Approach 1:
The system dynamically adjusts the filter bypass state based on the current operational mode. During TDD reception, the filter is bypassed to maximize sensitivity and SNR. In other operational modes, the filter is inserted to provide interference rejection. This dynamic adaptation resolves the contradiction by applying the appropriate configuration for each specific operational context.
3Device complexity
If a single antenna feed is used, then device complexity is reduced, but the ability to optimize performance for different carrier aggregation modes is limited
Solution Approach 1:
The patent segments the antenna interface into multiple independent antenna feeds (first antenna feed and second antenna feed), each capable of being independently configured with its own switching device and filter bypass capability. This segmentation allows each feed to be optimized for specific carrier aggregation modes, thereby improving adaptability while maintaining manageable complexity through modular design.
Solution Approach 2:
The multiple antenna feeds are designed to serve multiple functions across different carrier aggregation modes. Each antenna feed with its switching device can be configured to handle different operational requirements, making the system universally applicable to various CA modes (e.g., 1CA, 2CA, 3CA, 4CA) and TDD configurations, thus achieving versatility without proportionally increasing complexity.
Data Source
AI summary
An apparatus, including: a first antenna port; a first set of one or more band filters coupled to the first antenna port; a first set of one or more low noise amplifiers (LNAs) coupled to the first set of one or more band filters, respectively; a second antenna port; a second band filter; a second low noise amplifier (LNA); a first switching device coupled between the second antenna port and the second LNA; and a second switching device coupled between the second antenna port and the second band filter.