TDD Clock Synchronization Using Upstream Timing Recovery
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Solution Overview
Problem
Existing time division duplex (TDD) communication systems face challenges with tolerance to phase and frequency drift, affecting component cost and accuracy, particularly in terms of clock signal synchronization and alignment times.
Innovation Solution
A TDD communication system comprising a master and slave apparatus, where the slave apparatus transmits data based on its clock signal, and the master apparatus adjusts its clock signal during data reception to align with the slave's timing information, allowing for decoding and subsequent adjustment during downstream transmission to reduce phase and frequency changes, thereby improving synchronization and reducing alignment times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the master apparatus adjusts the phase and frequency of the master clock signal during reception of the slave data signal to enable decoding, then the tolerance to phase and frequency drift is improved, but the change in phase and frequency of the master clock signal increases
Solution Approach 1:
The master apparatus performs phase and frequency adjustment during the upstream reception period before the downstream transmission period begins. This preliminary adjustment ensures that the master clock signal is already optimized for receiving slave data, eliminating the need for additional alignment time at the start of downstream transmission and resolving the contradiction between drift tolerance and alignment time.
Solution Approach 2:
The master clock signal parameters (phase and frequency) are made dynamic and adjustable during the upstream period based on actual received signal characteristics. This dynamic adjustment allows the system to adapt to phase and frequency drift in real-time, improving reliability without requiring extended static alignment periods.
2Measurement precision
If the master apparatus adjusts the phase and frequency of the master clock signal during reception to enable decoding, then the timing accuracy is improved, but the device complexity increases
Solution Approach 1:
The phase and frequency adjustment functions are merged into the existing master apparatus clock management system. The master apparatus utilizes its existing clock recovery and synchronization capabilities to perform the adjustment, rather than introducing separate dedicated adjustment mechanisms. This integration achieves high timing accuracy while minimizing the increase in device complexity.
Solution Approach 2:
The system achieves improved timing accuracy by changing the parameters (phase and frequency) of the existing master clock signal through controlled adjustment during upstream reception. This approach avoids the need for completely separate high-precision timing mechanisms, thereby improving measurement precision without proportionally increasing device complexity.
3Stability of the object's composition
If the master apparatus adjusts the phase and frequency of the master clock signal during downstream transmission to reduce change, then the overall timing stability is improved, but the adaptability to slave apparatus variations decreases
Solution Approach 1:
The master apparatus uses feedback from the upstream reception process to determine the necessary phase and frequency adjustments. By continuously monitoring the slave data signal characteristics during upstream transmission and adjusting accordingly, the system achieves timing stability that adapts to each slave apparatus's specific characteristics, rather than using fixed pre-configured adjustments that would reduce adaptability.
Solution Approach 2:
The adjustment decisions are made during the upstream period based on actual measured conditions, allowing the master apparatus to adapt to each slave apparatus's specific timing characteristics. This preliminary adaptation ensures both stability during downstream transmission and versatility across different slave apparatus variations.
Data Source
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AI summary
A communication system comprising a master apparatus and a slave apparatus, wherein: the slave apparatus is configured, in an upstream period, to transmit a slave data signal to the master apparatus based on a slave clock signal; and the master apparatus is configured to: during reception of the slave data signal from the slave apparatus in the upstream period, extract timing information from the slave data signal and adjust a phase and/or frequency of a master clock signal or a definition thereof relative to a reference phase and/or frequency based on the extracted timing information to enable decoding of the received slave data signal based on the master clock signal or that definition; in a downstream period, transmit a master data signal to the slave apparatus based on the master clock signal according to the adjustment carried out during reception of the slave data signal in the upstream period; and adjust the phase and/or frequency of the master clock signal during transmission of the master data signal in the downstream period to reduce a change in the phase and/or frequency of the master clock signal effected according to the adjustment carried out during reception of the slave data signal in the upstream period.