Resonator-Based LO Generation for Fast Self-Interference Cancellation
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Solution Overview
Problem
In multiple radio access technology (RAT) and multi-band transceivers, concurrent transmission and reception cause interference, leading to an exponential increase in modulated and non-modulated spurs within the receiver's band, which existing technologies struggle to effectively mitigate due to the complexity and size of coil-based tuning circuits in phase locked loop (PLL) systems.
Innovation Solution
The implementation of a resonator-based local oscillator (LO) signal generation system, which uses a digital-to-time converter and is independent of coils, generating high-frequency signals suitable for interference cancellation, allowing for faster frequency tuning and reduced chip area, and optionally incorporates a phase locked loop for synchronization with a crystal oscillator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If coil-based tuning circuits are used in PLL systems to generate LO signals, then frequency tuning capability is achieved, but chip area increases and interference with surrounding analog circuitry occurs
Solution Approach 1:
The patent replaces the mechanical coil-based tuning circuit with a digitally controlled frequency synthesizer that uses a phase locked loop (PLL) with a numerically controlled oscillator (NCO). This substitution eliminates the need for physical inductors and capacitors, thereby reducing chip area while maintaining frequency tuning capability through digital control words.
Solution Approach 2:
The patent introduces a digital frequency control word as an intermediary between the digital domain and the analog LO signal generation. This control word allows precise frequency tuning without requiring physical tuning components, thus reducing chip area and avoiding interference with surrounding analog circuitry.
2Adaptability or versatility
If coil-based tuning circuits are used in PLL systems to generate LO signals, then frequency tuning capability is achieved, but interference with surrounding analog circuitry increases
Solution Approach 1:
The patent replaces the mechanical coil-based tuning circuit with a digitally controlled frequency synthesizer that uses a phase locked loop (PLL) with a numerically controlled oscillator (NCO). This substitution eliminates the need for physical inductors and capacitors, thereby reducing chip area while maintaining frequency tuning capability through digital control words.
Solution Approach 2:
The patent introduces a digital frequency control word as an intermediary between the digital domain and the analog LO signal generation. This control word allows precise frequency tuning without requiring physical tuning components, thus reducing chip area and avoiding interference with surrounding analog circuitry.
3Stability of the object's composition
If traditional PLL circuits are used for LO signal generation, then frequency stability is achieved, but frequency tuning speed is slow
Solution Approach 1:
The patent pre-calculates and stores frequency tuning parameters in lookup tables before actual frequency changes are needed. When a frequency change is required, the system simply retrieves the pre-computed values, significantly reducing the tuning time while maintaining frequency stability through the PLL's phase error correction mechanism.
Solution Approach 2:
The patent implements a dynamic frequency tuning mechanism where the PLL continuously adjusts the oscillator frequency based on real-time phase error feedback. This dynamic adjustment allows the system to quickly lock onto new frequencies while maintaining stability, overcoming the slow tuning speed of traditional PLL circuits.
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 new interference, enables faster frequency changes, and minimizes chip area, improving the efficiency of self-interference cancellation in transceivers by using stable high-frequency signals from resonators like bulk acoustic wave or micro-electro-mechanical system resonators.
Implementation Method 1
a resonator is used to generate a clock signal for use by a digital-to-time converter in generating the LO signal
Data Source
AI summary
Systems, methods, and circuitries are provided for resonator-based local oscillator signal generation for receiving self-interference signals. An interference cancellation system for a transceiver includes a resonator configured to generate a high-frequency signal and a local oscillator circuitry. The local oscillator circuitry includes a digital-to time converter configured to receive the high-frequency signal and, in response, generate a clock signal for receiving an interfering signal having an interference frequency. Digital cancellation circuitry is configured to adapt operation of the transceiver based, at least in part, on the received interfering signal.