Phase Correction for Microwave Backhaul Microphonics Cancellation
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Solution Overview
Problem
Conventional microwave backhaul architectures face challenges in achieving high capacity and reliability due to phase hits and microphonics, which hinder the development of high modulation and MIMO systems, especially when microwave local oscillator frequencies are in the range of 6 GHz to 43 GHz.
Innovation Solution
A mechanism for phase hits and microphonics cancellation is introduced, utilizing a stable signal reference at a lower frequency, such as 800 MHz, to generate a phase correction signal that is applied to the data path, enabling phase error correction through differential sampling or mixing of signals from an RF synthesizer and a reference source, thereby reducing phase noise and achieving immunity to phase hits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional microwave backhaul architectures are used with local oscillator frequencies in the range of 6 GHz to 43 GHz, then high capacity and high modulation systems can be implemented, but phase hits and microphonics occur which degrade signal quality and prevent zero bit error rate performance
Solution Approach 1:
A phase correction signal generated by an RF synthesizer locked to a stable reference (such as a temperature-controlled crystal oscillator) is introduced as an intermediary to cancel phase hits and microphonics in the local oscillator signal. The phase correction signal acts as a mediator that subtracts the harmful phase variations from the data path, enabling zero bit error rate performance while maintaining high capacity operations
Solution Approach 2:
The system implements feedback by continuously monitoring the phase of the local oscillator signal against a stable reference and generating corrective phase adjustment signals. The RF synthesizer is phase-locked to the reference oscillator, creating a feedback mechanism that actively compensates for phase hits and microphonics in real-time, ensuring reliable high-capacity transmission
2Productivity
If high modulation systems (such as 4096 QAM) and MIMO systems are implemented to increase capacity, then data transmission capacity is improved, but the systems become more sensitive to phase hits and microphonics which prevent achieving zero bit error rate
Solution Approach 1:
The phase correction signal from the RF synthesizer serves as an intermediary that specifically targets and cancels phase errors in the data path. By introducing this correction mechanism, high modulation systems can operate at their full capacity potential without being degraded by phase hits and microphonics, achieving zero bit error rate performance
Solution Approach 2:
The system changes the phase parameter of the local oscillator signal by applying correction signals that adjust the phase to match the stable reference. This parameter change compensates for phase hits and microphonics, enabling high modulation systems to maintain the precision required for zero bit error rate while operating at high capacities
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 solution enables high modulation and MIMO systems to achieve zero bit error rate performance by effectively canceling phase hits and microphonics, supporting higher capacity systems like 4096 QAM and 4×4 spatial MIMO systems.
Implementation Method 1
The phase correction signal can be generated by an RF synthesizer that is locked to a stable reference, such as a temperature controlled crystal oscillator
Implementation Method 2
The phase correction signal is applied to a data path to cancel phase hits and microphonics
Data Source
AI summary
A system and method for system, method and apparatus for phase hits and microphonics cancellation. In addition to a first RF synthesizer source, a device also includes a second stable reference signal source that operates at a lower frequency as compared to the RF synthesizer source. The second stable reference signal source is selected with good phase noise characteristics and can be used to correct phase error events.