TDD Clock Synchronization for Phase and Frequency Drift Compensation
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Solution Overview
Problem
Existing time division duplex (TDD) communication systems face challenges with tolerance to phase and frequency drift, affecting the cost and accuracy of components, particularly in terms of clock signal alignment and synchronization during upstream and downstream data transmission periods.
Innovation Solution
A 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 accurate decoding and synchronization, and then adjusts the master clock signal during downstream transmission to compensate for phase and frequency changes caused by the initial adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the master apparatus adjusts its clock signal phase and frequency during upstream data reception to align with the slave's timing, then decoding accuracy is improved, but the clock signal experiences phase and frequency drift that affects downstream transmission timing
Solution Approach 1:
The system applies preliminary anti-action by measuring the phase and frequency changes during upstream reception and then applying compensating adjustments during downstream transmission. The master apparatus pre-calculates the necessary counter-adjustment based on the drift observed during upstream period, thereby preventing timing errors before they affect downstream data transmission to the slave apparatus
Solution Approach 2:
The system implements feedback by continuously monitoring the phase and frequency of the clock signal during upstream data reception, measuring the actual drift that occurs, and using this measurement to determine the compensating adjustment needed for downstream transmission. This closed-loop feedback ensures that timing accuracy is maintained across both upstream and downstream periods
2Device complexity
If the master apparatus uses a static clock signal definition, then system simplicity is maintained, but tolerance to phase and frequency drift is reduced
Solution Approach 1:
The system transitions from a static clock signal definition to a dynamic one by allowing the master apparatus to adjust the phase and frequency of its clock signal based on actual drift measurements. The clock signal definition becomes adaptive, changing in real-time during upstream reception and subsequently compensating during downstream transmission, thereby providing tolerance to phase and frequency drift while maintaining manageable system complexity through automated adjustment
3Measurement precision
If the slave apparatus waits for clock alignment during downstream period, then timing accuracy is improved, but the locking time is increased
Solution Approach 1:
The system applies preliminary action by having the master apparatus perform the clock alignment adjustment during the upstream data reception period before the downstream period begins. By completing the phase and frequency synchronization work in advance during upstream transmission, the slave apparatus receives pre-aligned clock signals during downstream period, eliminating the need for extended waiting and locking time while maintaining high timing accuracy
Data Source
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.