Reference Crystal Oscillator Switching for Low-Noise 5G Transceivers
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The introduction of 5G cellular communications systems with higher radio frequencies necessitates reference crystal oscillators (XOs) that maintain low phase noise and reduced power consumption, but conventional XOs face issues such as increased tolerance and power consumption when operating at frequencies above 10 GHz.
Innovation Solution
A wireless device is equipped with two XOs, one operating at a lower frequency (e.g., 20-40 MHz) and another at a higher frequency (e.g., 100 MHz or more), intelligently switching between them based on synchronization state, connection state, and carrier frequency to optimize phase noise and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a higher frequency XO (100 MHz or more) is used to reduce phase noise amplification and meet stringent phase noise requirements for 10 GHz and above carrier frequencies, then phase noise performance is improved, but power consumption increases significantly (5 to 10 times greater than 20-40 MHz XO)
Solution Approach 1:
The patent implements dynamic XO frequency selection by equipping the wireless device with multiple XOs operating at different frequencies (e.g., 20-40 MHz and 100 MHz or more) and intelligently switching between them based on the carrier frequency being used. This allows the system to adapt the XO frequency dynamically - using higher frequency XOs when operating at 10 GHz and above to meet phase noise requirements, and lower frequency XOs for lower carrier frequencies to conserve power.
2Reliability
If a higher frequency XO is used to reduce phase noise amplification, then phase noise performance is improved, but frequency tolerance increases (e.g., 26 MHz XO may have 10 ppm tolerance while >100 MHz XO may have 40-50 ppm tolerance)
Solution Approach 1:
The system dynamically selects the appropriate XO frequency based on the carrier frequency being used. When operating at lower carrier frequencies, the system uses lower frequency XOs with better frequency tolerance. When operating at 10 GHz and above where phase noise requirements are stringent, the system switches to higher frequency XOs despite their looser tolerance, as the phase noise benefit outweighs the tolerance drawback in this specific operating regime.
3Reliability
If XO frequency is increased from less than 50 MHz to greater than or equal to 100 MHz to mitigate phase noise amplification, then phase noise performance is improved, but device complexity increases due to discontinuous step with regards to manufacturing and mechanical structure of the resonator
Solution Approach 1:
The patent segments the XO frequency range into distinct bands (e.g., 20-40 MHz and 100 MHz or more) and provides separate XO components for each band. This segmentation allows the system to use simpler, lower frequency XOs for lower carrier frequencies while having the capability to switch to higher frequency XOs when needed for 10 GHz and above operations, managing the complexity through modular design.
4Use of energy by moving object
If a lower frequency XO (20-40 MHz) is used, then power consumption is reduced and frequency tolerance is better, but phase noise amplification increases which may not meet requirements for 10 GHz and above carrier frequencies
Solution Approach 1:
The system implements dynamic XO frequency selection based on the carrier frequency being used. When operating at lower carrier frequencies, the system uses lower frequency XOs (20-40 MHz) to conserve power and benefit from better frequency tolerance. When operating at 10 GHz and above where phase noise requirements are stringent, the system switches to higher frequency XOs (100 MHz or more) to reduce phase noise amplification, accepting the higher power consumption and looser tolerance as necessary trade-offs for meeting performance 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 Phase Locked 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 deciding 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.