Wireless Clock Synchronization via MAC-PHY Layer Interaction
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Solution Overview
Problem
Current wireless communication protocols face challenges in achieving high accuracy clock synchronization between devices in wireless networks, particularly due to synchronization delay jitter and clock drift, which affect the precision of time synchronization.
Innovation Solution
A method and system for high accuracy clock synchronization in wireless communication systems, involving the transmission of synchronization frames with timestamps, where the receiving device adjusts its local time based on the difference between the transmitted and received timestamp, minimizing synchronization delay jitter by interacting between communication layers and sub-layers, specifically at the MAC and PHY layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If timestamp-based synchronization is used in wireless networks, then time synchronization can be achieved between devices, but synchronization delay jitter and clock drift reduce the precision of time synchronization
Solution Approach 1:
The patent implements a feedback mechanism where the receiving device calculates the time difference between its local clock and the transmitter's timestamp, then adjusts its local clock based on this difference. The system continuously monitors synchronization accuracy and makes real-time corrections to compensate for clock drift and delay jitter, thereby improving synchronization precision while maintaining stability
Solution Approach 2:
The patent introduces an intermediary synchronization protocol that operates between the MAC and PHY layers. This intermediary layer processes timestamp information, calculates synchronization offsets, and coordinates clock adjustments across multiple devices. By placing the synchronization function at this intermediate level, the system can account for processing delays and jitter more accurately than direct endpoint synchronization
2Device complexity
If clock synchronization is performed at higher communication layers, then synchronization logic can be simplified, but synchronization accuracy decreases due to layer processing delays
Solution Approach 1:
The patent performs preliminary timing measurements and delay characterizations at the PHY layer before data passes to higher layers. By pre-calculating and compensating for processing delays at each layer in advance, the system maintains high synchronization accuracy without requiring complex real-time adjustments at the MAC or network layers. The synchronization timestamp is adjusted beforehand to account for known processing delays
Data Source
AI summary
Time synchronization in a wireless communication system comprises transmitting a synchronization frame from a transmitter to a receiver over a wireless communication medium. The synchronization frame includes a timestamp indicating the transmitter local time when a symbol at a predefined position of the synchronization frame is placed on the wireless communication medium for transmission. The synchronization frame is received at the receiver which determines a receiving time comprising the receiver local time when said symbol of the synchronization frame was received at the physical layer of the receiver. Time synchronizing is performed by determining a difference between said timestamp and said receiving time, and adjusting the receiver local time based on said difference to time synchronize the receiver with the transmitter.