Wireless Network Time Synchronization with Propagation Delay Measurement
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Solution Overview
Problem
Wireless networks face inefficiencies due to varying propagation delay times between units, necessitating long guard times in TDD systems, which reduces channel efficiency as distances increase.
Innovation Solution
A method for clock synchronization that involves transmitting and receiving messages between corrected and uncorrected units to calculate and apply a clock offset, correcting for propagation delay times to synchronize clocks accurately.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If guard time is increased to accommodate varying propagation delay times, then time synchronization reliability is improved, but channel efficiency deteriorates
Solution Approach 1:
The patent changes the parameter of guard time from a fixed maximum value to a dynamically adjusted value based on actual measured propagation delay times. By continuously monitoring and adapting the guard time parameter to match real-time network conditions, the system maintains sufficient time synchronization reliability while minimizing unnecessary guard time allocations, thereby improving channel efficiency.
2Object-affected harmful factors
If guard time is increased to account for largest propagation delay time, then interference between time slots is prevented, but network efficiency deteriorates
Solution Approach 1:
Instead of applying excessive guard time to all unit pairs, the patent implements partial action by measuring and applying guard time specifically tailored to each unit pair's actual propagation delay characteristics. This selective approach prevents interference where needed while avoiding unnecessary guard time in cases with smaller propagation delays, thereby maintaining network efficiency.
3Length of stationary object
If distance between transmitter and receiver increases, then network coverage is improved, but channel efficiency drops due to longer guard time requirements
Solution Approach 1:
The patent introduces dynamics by making the guard time adaptive rather than static. The system continuously measures propagation delay times and adjusts guard time allocations dynamically based on actual distance and signal conditions. This allows the network to support larger distances between units while maintaining optimal channel efficiency, as guard time is adjusted in real-time rather than being fixed for all scenarios.
Data Source
AI summary
Clock synchronization, including: receiving a first message at an uncorrected unit with a propagation delay time, wherein a transmission time of the first message is recorded by a corrected unit; recording an arrival time of the first message by the uncorrected unit; transmitting a second message from the uncorrected unit to the corrected unit after a pre-determined delay, receiving a third message at the uncorrected unit, wherein the third message includes a propagation delay time and the transmission time of the first message recorded by the corrected unit; calculating a clock offset between the corrected unit and the uncorrected unit using the propagation delay time and the transmission time of the first message recorded by the corrected unit; and applying the clock offset to synchronize a clock of the uncorrected unit to a clock of the corrected unit.