Two-Stage LNA Routing for Carrier Aggregation Isolation
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Solution Overview
Problem
In carrier aggregation communication systems, receiver path isolation is challenging due to internal aggressor signals and external interferers, making it difficult to recover information from multiple carrier signals effectively.
Innovation Solution
A two-stage low noise amplifier (LNA) is used to efficiently route received RF carrier signals in multiple communication bands to demodulators, providing improved receiver path isolation and consistent performance by using a first and second amplification stage with band group LNAs and routing modules to minimize noise and signal degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple receive paths are used to simultaneously receive multiple carrier signals, then the receiver can process multiple carriers in carrier aggregation systems, but internal aggressor signals are generated that cause receiver desensitization and make information recovery difficult
Solution Approach 1:
The receiver is divided into multiple independent receive paths, each with its own LNA and signal processing chain. This segmentation allows each path to process a specific carrier signal independently, reducing interference between paths while maintaining the ability to receive multiple carriers simultaneously
Solution Approach 2:
A coupling mechanism is introduced between the LNA output and the rest of the receiver chain. This intermediary coupling structure provides isolation between different receive paths, preventing internal aggressor signals from one path from desensitizing other paths while still allowing the system to process multiple carriers
2Adaptability or versatility
If multiple receive paths are implemented to handle multiple carriers, then carrier aggregation capability is achieved, but path-to-path isolation requirements become stringent due to aggressor signals generated by each receiver signal path
Solution Approach 1:
The receiver architecture is segmented into independent processing chains, with each receive path having dedicated LNAs and signal processing components. This segmentation reduces the coupling between paths and simplifies the isolation requirements compared to a shared processing architecture
Solution Approach 2:
Each receive path is designed with local optimization for its specific carrier frequency, including band-specific LNAs and filtering. This local quality approach allows each path to be optimized independently, reducing the complexity of achieving isolation across all paths while maintaining overall carrier aggregation functionality
Data Source
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AI summary
A radio frequency (RF) front end having multiple low noise amplifiers modules is disclosed. In an exemplary embodiment, an apparatus includes at least one first stage amplifier configured to amplify received carrier signals to generate at least one first stage carrier group. Each first stage carrier group includes a respective portion of the carrier signals. The apparatus also includes second stage amplifiers configured to amplify the first stage carrier groups. Each second stage amplifier configured to amplify a respective first stage carrier group to generate two second stage output signals that may be output to different demodulation stages where each demodulation stage demodulates a selected carrier signal.