Full-Duplex Radio Predistortion Using a Shared Receive Chain
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Solution Overview
Problem
Full-duplex radio communications face challenges in spectrum utilization due to interference between transmitted and received signals, making commercial implementation difficult, and existing techniques require additional receiver chains for digital predistortion, increasing complexity and power consumption.
Innovation Solution
The use of digital predistortion in full-duplex radio systems that allows for simultaneous transmission and reception using overlapping frequency resources, leveraging the existing receive chain circuitry for both interference cancellation and predistortion, eliminating the need for an additional receiver chain and improving nonlinear interference cancellation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional receiver chain is added for digital predistortion, then predistortion performance is improved, but device complexity and power consumption increase
Solution Approach 1:
The patent makes the existing receive chain perform dual functions: processing received signals and capturing transmitted signals for digital predistortion. By configuring the receive chain to operate in full-duplex mode, the system eliminates the need for a separate predistortion receiver chain, thereby reducing device complexity while maintaining predistortion performance
Solution Approach 2:
The patent combines the functions of the receive chain and the predistortion measurement chain into a single integrated receive chain. The transmitted signal path is merged with the receive chain by using the same hardware components (LNA, mixer, ADC) for both receiving external signals and monitoring transmitted signals for predistortion calculations
2Reliability
If additional receiver chain is added for digital predistortion, then predistortion performance is improved, but power consumption increases
Solution Approach 1:
The receive chain is designed to perform multiple functions simultaneously: receiving external signals and capturing transmitted signals for predistortion. This multi-functionality eliminates the need for a separate power-consuming predistortion receiver chain, thereby reducing overall power consumption while maintaining predistortion performance
Solution Approach 2:
By merging the predistortion measurement function into the existing receive chain, the patent avoids the additional power consumption that would result from operating a separate receiver chain dedicated to predistortion signal capture
3Productivity
If full-duplex radio is implemented, then spectrum utilization is improved, but signal interference increases
Solution Approach 1:
The patent applies digital predistortion to the transmitted signal before transmission to pre-compensate for nonlinear distortions. By calculating the inverse of the expected distortion and applying it in advance, the system reduces self-interference effects before they occur, enabling better full-duplex operation
Solution Approach 2:
The patent uses the receive chain to capture the transmitted signal and feed it back to a processing element that calculates distortion characteristics. This feedback loop enables continuous adaptation of predistortion parameters to compensate for changing interference conditions and maintain spectrum utilization
Data Source
AI summary
Techniques are disclosed relating to use of digital predistortion in the context of full-duplex radio. In some embodiments, an apparatus includes one or more antennas and is configured to simultaneously transmit and receive wireless signals via at least partially overlapping frequency resources using the one or more antennas. In some embodiments, the apparatus includes receive chain circuitry that is configured to process both wireless signals transmitted by the apparatus via the one or more antennas and over-the-air wireless signals from one or more other computing devices. In some embodiments, the apparatus includes one or more processing elements configured to determine one or more digital predistortion parameters based on the wireless signals transmitted by the apparatus via the one or more antennas and processed by the receive chain circuitry and apply predistortion to transmitted wireless signals based on the one or more digital predistortion parameters.