RF Front-End Architecture for Intra-Band RIMD Isolation
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Solution Overview
Problem
In RF communication systems, especially during dual connectivity and carrier aggregation, intra-band intermodulation distortion (IMD) challenges arise due to concurrent transmission and reception on overlapping bands, leading to performance issues such as reverse intermodulation distortion (RIMD) and reduced power amplification, which affects 5G service coverage and capacity.
Innovation Solution
The implementation of a radio frequency front-end system with specific duplexing paths and filters that allow for intra-band transmission through Tx and Rx filters overlapping with the bands used for intra-band transmission, enabling better isolation and reducing RIMD, thereby increasing power amplification and coverage for 5G services.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If concurrent transmission and reception are performed on overlapping bands, then system functionality and service capacity are improved, but intra-band intermodulation distortion increases causing performance degradation
Solution Approach 1:
The patent segments the RF front-end into separate FDD and TDD paths with dedicated filters for each band. The FDD path includes FDD Rx and Tx filters, while the TDD path includes TDD Rx and Tx filters, allowing independent optimization of each path to minimize intermodulation distortion while maintaining concurrent operation capability.
Solution Approach 2:
The patent introduces specialized filter components as intermediaries between the power amplifier and antenna. These include FDD Tx filters, TDD Tx filters, and TDD Rx filters that act as mediators to selectively pass desired signals while blocking intermodulation products, thereby reducing the harmful effects of concurrent transmission and reception.
2Power
If power amplification is increased to enhance coverage, then service coverage and capacity are improved, but reverse intermodulation distortion increases affecting reception quality
Solution Approach 1:
The patent applies TDD Tx filters before the power amplifier in the TDD path to pre-filter the transmit signal. This preliminary filtering action prevents intermodulation products from being generated in the first place, allowing the power amplifier to operate at high power levels without creating harmful reverse intermodulation distortion that would affect reception quality.
3Reliability
If conventional LTE band filtering is used, then LTE compatibility is maintained, but flexibility in transmission connectivity is reduced
Solution Approach 1:
The patent designs the RF front-end with multi-functional filter components that can operate with both conventional LTE bands and new TDD bands. The FDD and TDD paths are designed to be universally compatible, allowing the system to maintain LTE compatibility while providing flexibility for various transmission connectivity scenarios including TDD intra-band EN-DC use cases.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly reduces RIMD, enhances 5G service coverage and capacity, and increases flexibility in transmission connectivity by allowing higher power levels for TDD intra-band EN-DC use cases, while maintaining compatibility with conventional LTE bands.
Implementation Method 1
a first frequency division duplex path corresponding to a first frequency division duplex band and including a first duplexer
Implementation Method 2
implementation of a radio frequency front-end system with specific duplexing paths and filters that allow for intra-band transmission through Tx and Rx filters overlapping with the bands used for intra-band transmission
Data Source
AI summary
A radio frequency front end system includes a first frequency division duplex path corresponding to a first frequency division duplex band and including a first duplexer. The system can also include a first time division duplex transmit path corresponding to a first time division duplex band that overlaps with the first frequency division duplex band. The first time division duplex transmit path can have a first transmit amplifier and a first switch. The switch can be configured in at least one first operating mode of the radio frequency front end system, to connect the first transmit amplifier to a first antenna via the first duplexer to transmit in the first time division duplex band.