Tunable Diplex Filter for Carrier Aggregation and Duplex Isolation
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Solution Overview
Problem
Existing cellular radio communication systems face challenges in supporting multiple frequency bands due to the need for multiple hardware sets, duplex self-interference issues, and interactions between receive pass bands, particularly in carrier aggregation scenarios, where prior art fixed frequency filters are not adaptable to various band combinations.
Innovation Solution
The implementation of an adaptive multi-carrier filter response system featuring a tunable diplex filter that separates signals into high-pass and low-pass output nodes, allowing programmable reject and pass band characteristics to minimize interference and support multiple frequency bands and carrier aggregation combinations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fixed frequency filters are used for each band, then filtering performance for specific bands is improved, but device complexity and hardware quantity increase
Solution Approach 1:
The patent implements a universal filter system where a single filter can operate across multiple frequency bands by dynamically adjusting its characteristics. The filter is designed to support carrier aggregation scenarios where it must handle multiple receive bands simultaneously while rejecting transmit frequencies, replacing the need for separate fixed filters for each band combination.
Solution Approach 2:
The patent employs dynamically tunable filters whose passband and rejectband characteristics can be adjusted in real-time. The filter responds to control signals that configure its frequency response based on the current operating mode, allowing it to adapt to different carrier aggregation scenarios and frequency band combinations without requiring hardware changes.
2Adaptability or versatility
If multiple receive bands are passed through fixed frequency filters, then multi-band reception is enabled, but filter interactions cause signal distortion
Solution Approach 1:
The patent implements a control system that monitors the filter bank's operation and dynamically adjusts filter characteristics to prevent harmful interactions. The system receives control signals that configure the passband and rejectband settings of multiple filters based on the current carrier aggregation scenario, ensuring that filters are coordinated to avoid signal distortion while maintaining multi-band reception capability.
Solution Approach 2:
The patent pre-configures the filter bank with multiple filters designed to handle specific frequency relationships. Before operation in a given carrier aggregation mode, the control system selects and activates the appropriate filter configuration, preliminarily setting the passband and rejectband characteristics to prevent interactions before they occur during signal processing.
3Object-affected harmful factors
If transmit and receive antennas are separated for duplex isolation, then duplex self-interference is reduced, but device area increases
Solution Approach 1:
The patent introduces a filter as an intermediary component in the receive signal path that actively rejects transmit frequencies before they can interfere with receive signals. This filter-based approach provides duplex isolation without requiring physical separation of antennas, allowing transmit and receive antennas to be co-located while maintaining signal integrity through frequency-selective filtering.
Data Source
AI summary
The present subject matter relates to devices, systems, and methods that provide a programmable filter response in a wireless frequency division duplex system. In particular, in some embodiments, a tunable diplex filter for such a system includes a first tunable filter in communication between an input node and a first output node, the first tunable filter being tunable to define a first tunable pass band configured to have a minimum pass band insertion loss at frequencies that are higher than a first reject band, and a second tunable filter in communication between the input node and a second output node, the second tunable filter being tunable to define a second tunable pass band configured to have a minimum pass band insertion loss at frequencies that are lower than the first reject band.