Reference Crystal Oscillator Switching for 5G Transceiver Phase Noise
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Solution Overview
Problem
The transition to 5G wireless devices requires higher frequency reference crystal oscillators to maintain low phase noise levels, but these high-frequency oscillators have larger frequency tolerance variations, higher power consumption, and manufacturing challenges, making them less efficient than conventional 20-40 MHz oscillators.
Innovation Solution
Implementing a wireless device with two reference crystal oscillators, one operating at a lower frequency (20-40 MHz) and another at a higher frequency (≥100 MHz), allowing the device to dynamically switch between them based on operational needs, such as synchronization state and carrier frequency, to optimize phase noise and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a high-frequency reference crystal oscillator (≥100 MHz) is used to maintain low phase noise levels at 10 GHz and above, then phase noise performance is improved, but power consumption increases significantly and frequency tolerance variations worsen
Solution Approach 1:
The patent implements dynamic switching between a first reference crystal oscillator (20-40 MHz) and a second reference crystal oscillator (≥100 MHz) based on operational conditions. The system evaluates whether high-frequency operation is currently needed and switches to the lower-frequency oscillator when possible, reducing power consumption while maintaining phase noise performance when required.
Solution Approach 2:
The system changes the operating frequency parameter of the reference crystal oscillator based on operational mode. By switching between 20-40 MHz and ≥100 MHz operating frequencies, the system adapts power consumption and phase noise characteristics to match current operational requirements, using higher frequency only when stringent phase noise requirements exist.
2Measurement precision
If a high-frequency reference crystal oscillator (≥100 MHz) is used to suppress phase noise amplification, then phase noise performance is improved, but frequency tolerance variations increase
Solution Approach 1:
The system dynamically selects which oscillator to use based on whether stringent phase noise requirements are currently active. When operating in modes that don't require ultra-low phase noise, the system uses the 20-40 MHz oscillator with better frequency tolerance. When high-frequency operation is needed, it switches to the ≥100 MHz oscillator, accepting the tolerance trade-off only when necessary.
Solution Approach 2:
The system changes the frequency parameter of the reference oscillator to match operational requirements. The lower-frequency oscillator (20-40 MHz) provides better manufacturing precision and frequency tolerance, while the higher-frequency oscillator (≥100 MHz) provides better phase noise performance. The system selects the appropriate parameter set based on current operational mode.
3Measurement precision
If the reference crystal oscillator frequency is increased from 20-40 MHz to ≥100 MHz, then phase noise amplification is reduced, but device complexity increases due to manufacturing challenges
Solution Approach 1:
The patent segments the oscillator system into two distinct reference crystal oscillators with different frequency capabilities. Instead of requiring a single complex high-frequency oscillator, the system uses a first oscillator (20-40 MHz) for general operation and a second oscillator (≥100 MHz) for high-performance modes, switching between them based on requirements.
Solution Approach 2:
The system implements multi-functionality by having the reference oscillator subsystem serve different operational modes. The first oscillator handles power-efficient and tolerance-critical operations, while the second oscillator handles phase-noise-critical operations. This universal design allows one oscillator system to satisfy multiple conflicting requirements.
Data Source
AI summary
Systems and methods are disclosed herein that relate to a wireless device that intelligently uses different reference crystal oscillators (XOs) for a PhaseLocked Loop(s) (PLL(s)) in a transceiver of the wireless device. Embodiments of a method of operation of a wireless device comprising a first XO that operates at a first reference frequency and a second XO that operates at a second reference frequency that is greater than the first reference frequency are disclosed. In some embodiments, the method of operation of the wireless devices comprises making a decision as to whether to configure a receiver of the wireless device to use the first XO or the second XO and configuring the receiver of the wireless device to use the first XO or the second XO in accordance with the decision.