Adjustable RF Filter Architecture for FDD/TDD Band Overlap
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Solution Overview
Problem
Existing RF communication systems face challenges in efficiently managing signal transmission and reception in frequency-division duplexing and time-division duplexing modes, particularly in advanced cellular technologies like LTE-Advanced and 5G NR, due to the complexity of supporting multiple frequency bands and duplexing methods, which can lead to increased power consumption and hardware requirements.
Innovation Solution
The implementation of an adjustable filter architecture in the front-end system of mobile devices, incorporating multi-throw switches and bandpass/stopband filters, allows for flexible operation in various duplexing modes, enabling efficient signal management across overlapping frequency bands and reducing the need for multiple power amplifiers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple power amplifiers are used to support multiple frequency bands and duplexing modes, then the system can handle diverse communication requirements, but the hardware complexity and power consumption increase
Solution Approach 1:
The adjustable filter is designed to perform multiple functions by dynamically reconfiguring its filtering characteristics. A single filter architecture supports both frequency-division duplexing and time-division duplexing modes across multiple frequency bands (e.g., n78, n77, n5) by adjusting switch states, eliminating the need for separate dedicated filters for each mode and band combination.
Solution Approach 2:
The filter system employs dynamic reconfiguration through multi-throw switches that can change the filter's operational mode in real-time. The filter transitions between FDD and TDD modes, and adjusts its passband/stopband characteristics dynamically based on the required duplexing mode and frequency band, allowing one hardware component to adapt to varying communication requirements.
2Adaptability or versatility
If multiple power amplifiers are used to support multiple frequency bands and duplexing modes, then the system can handle diverse communication requirements, but the power consumption increases
Solution Approach 1:
A single power amplifier is designed to operate across multiple frequency bands and duplexing modes by combining it with the dynamically reconfigurable adjustable filter. This universal configuration allows one power amplifier to replace multiple dedicated amplifiers, directly reducing power consumption while maintaining support for diverse communication requirements.
Solution Approach 2:
The patent merges the functions of multiple dedicated filter-amplifier pairs into a single integrated system. By combining the adjustable filter (which handles frequency selection and duplexing mode separation) with a single power amplifier, the system achieves the functionality of multiple separate components with reduced power consumption and lower hardware complexity.
3Device complexity
If fixed filter architecture is used, then the design is simpler, but the system cannot efficiently switch between different duplexing modes and frequency bands
Solution Approach 1:
The filter architecture incorporates dynamic elements through multi-throw switches that can reconfigure the filter's internal connections based on the required operating mode. The filter transitions between FDD and TDD configurations, and adjusts its frequency response characteristics dynamically, maintaining relatively simple base architecture while achieving high adaptability through controlled reconfiguration.
Solution Approach 2:
The filter is pre-designed with multiple possible configurations and switching paths built into its architecture. The switch states are predetermined for different operating modes (FDD, TDD, different frequency bands), allowing the filter to quickly transition between modes without complex real-time calculations, balancing design simplicity with operational flexibility.
Data Source
AI summary
Front-end systems with an adjustable filter architecture are provided. In certain embodiments, a front-end system includes a first bandpass filter with a first passband, a second bandpass filter with a second passband, a stopband filter with a stopband, and switches for controlling connectivity of the filters along transmit and receive paths. The first passband and the second passband include a frequency overlap region, which the stopband at least partially overlaps. The re-configurability of the switches allows for the overall filtering characteristic of the adjustable filter to adjust the duplex gap between transmit and receive passband edges, as well as the passband edges themselves.