Digital Antenna Switching Eliminates RF Insertion Loss
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Solution Overview
Problem
Antenna switching in wireless terminals often results in signal attenuation and distortion due to the use of radio frequency (RF) switches, which also occupy valuable space and are expensive.
Innovation Solution
Implementing a digital switch circuit that converts analog received signals to digital signals and switches between them to supply the appropriate signals to modem modules, eliminating the need for RF switches and thereby reducing insertion loss and impairments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If RF switches are used for antenna switching, then antenna switching functionality is achieved, but insertion loss and signal distortion occur
Solution Approach 1:
The patent replaces the mechanical RF switch with a digital signal processing approach. Multiple antennas are connected to multiple ADCs, and a processor selectively routes digital signals from different ADCs to different modem instances, eliminating the need for physical RF switching and its associated insertion loss.
Solution Approach 2:
The patent changes the domain of signal switching from the RF domain to the digital domain. By performing antenna selection after ADC conversion rather than before, the system avoids RF switch losses while maintaining the ability to switch between antennas based on signal quality metrics.
2Reliability
If RF switches are used for antenna switching, then antenna switching functionality is achieved, but signal distortion and nonlinearities occur
Solution Approach 1:
The patent eliminates the RF switch component entirely by using digital signal routing. The processor selectively connects digital outputs from different ADCs to different modem instances through digital signal paths, avoiding the nonlinearities and intermodulation products generated by RF switches.
3Adaptability or versatility
If RF switches are used for antenna switching, then antenna switching functionality is achieved, but device complexity and physical space increase
Solution Approach 1:
The patent makes the ADCs and processor serve multiple functions. Each ADC can serve multiple antenna inputs, and the processor dynamically routes signals from any ADC to any modem instance, eliminating the need for dedicated RF switches for each antenna path and reducing overall circuit complexity.
Solution Approach 2:
The patent merges the antenna switching function into the digital signal processing domain by combining multiple ADC outputs and routing them through a shared processor resource. This consolidation eliminates separate RF switch components and reduces the overall circuit footprint.
4Adaptability or versatility
If RF switches are used for antenna switching, then antenna switching functionality is achieved, but manufacturing cost increases
Solution Approach 1:
The patent replaces expensive RF switch components with digital signal processing capabilities that can be implemented in existing processors and ADCs. This substitution eliminates the need for additional expensive RF components while maintaining antenna switching functionality.
Data Source
AI summary
Systems and methods for antenna switching without using a radio-frequency switch are provided. A signal received via a first antenna is digitized to form a first digital received signal. A signal received via a second antenna is digitized to form a second digital received signal. A switch selects the first digital received signal or the second digital received signal to be supplied to a modem to be demodulated. The switch may also supply a digital transmit signal from the modem to be supplied to digital-to-analog converters to and then transmitted using the first or second antenna. Additionally, when the modem is demodulating the signal received via the first antenna, another modem may be demodulating the signal received via the second antenna and vice versa.