Multiband Radio Front-End Filter Architecture
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Solution Overview
Problem
Conventional multiband radio base station front-end filters, particularly air cavity duplexers, occupy a large share of the radio unit's size, weight, and cost due to their high-power handling requirements, which becomes exacerbated with the increasing complexity of MIMO configurations in 5G wireless networks.
Innovation Solution
A wireless receiver multiband filter architecture that employs wideband filters to capture multiple adjacent sub-bands and a small multiplexor to isolate individual sub-bands, utilizing ceramics or SAW/BAW/FBAR filters, reducing the size, weight, and cost by splitting the filtering load into wideband and single sub-band filtering stages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If air cavity multiband duplexer is used to filter multiple sub-bands, then signal filtering performance is improved, but the size, weight, and cost of the radio unit increases significantly
Solution Approach 1:
The patent divides the filtering function into two separate stages: a wideband filter that handles multiple sub-bands simultaneously, and individual single-subband filters that process each isolated sub-band. This segmentation allows the system to achieve comprehensive filtering performance while using smaller, more compact filter components rather than one large air cavity duplexer for all sub-bands
Solution Approach 2:
The wideband filter is designed to handle multiple sub-bands with a single component, making it a multi-functional element that replaces what would traditionally require multiple separate air cavity filters. This universal filtering approach reduces the overall number of components and the total volume occupied by filtering hardware
2Power
If air cavity multiband duplexer is used to handle high-power transmit signals, then power handling capability is improved, but the device complexity and manufacturing cost increase
Solution Approach 1:
The patent segments the power handling function by assigning the high-power transmit signal filtering to the wideband filter stage, while the subsequent single-subband filters operate at lower power levels after signal isolation. This segmentation simplifies the requirements for individual filter components while maintaining overall high-power handling capability
Solution Approach 2:
The wideband filter acts as an intermediary component that handles the high-power transmit signals and performs initial filtering, thereby protecting downstream low-power components from excessive power exposure. This intermediary function reduces the complexity requirements for subsequent filter stages
3Reliability
If conventional air cavity duplexer design is used, then signal isolation between sub-bands is achieved, but the weight of the radio unit becomes excessive
Solution Approach 1:
The filtering architecture is segmented into a wideband filter stage that provides initial signal isolation across multiple sub-bands, followed by individual single-subband filter stages that provide precise isolation for each sub-band. This segmentation achieves comprehensive signal isolation while using lighter-weight filter components compared to a single large air cavity duplexer
Solution Approach 2:
The patent changes the operational parameters of the filtering system by using a wideband filter with broader frequency coverage followed by narrowband filters for specific sub-bands, rather than using multiple wideband air cavity filters. This parameter change enables the use of lighter materials and smaller component sizes while maintaining isolation performance
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 the size, weight, and cost of the air cavity multiband duplexer while maintaining effective signal isolation and noise protection, achieving a smaller form-factor and lower signal loss compared to conventional designs.
Implementation Method 1
one or more wideband filters, where each of the wideband filters are configured to filter any group of two or more adjacent sub-bands in a frequency spectrum
Implementation Method 2
a multiplexer configured to isolate each of the adjacent uplink sub-bands bands using separate filters
Implementation Method 3
a plurality of single sub-band filters, each of the plurality of single sub-band filters configured to filter a different isolated uplink sub-band
Data Source
AI summary
A multiband radio (108) is presented that includes front-end architecture that can produce a substantial size/weight/cost reduction on the necessary air cavity multiband receive filter design of existing multiband radio (108)s. In particular, the disclosure presents a multiband radio (108) configured to filter a set of sub-bands of a multiband uplink signal. In an aspect, the multiband radio (108) includes one or more wideband filters (206) configured to filter any group of two or more adjacent sub-bands in a frequency spectrum utilized by the multiband radio (108) for communication with one or more user equipment (UE). In addition, the multiband radio (108) includes a multiplexer (343, 542) configured to isolate each of the uplink sub-bands using separate filters (340, 540). Furthermore, the multiband radio (108) includes a plurality of single sub-band filters (410), each of the plurality of single sub-band filters (410) configured to filter a different isolated uplink sub-band in the frequency spectrum.