Wireless Time Synchronization Using Propagation Time Estimation
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Solution Overview
Problem
Existing communication systems face challenges in achieving precise time synchronization across network nodes, particularly in scenarios requiring sub-microsecond accuracy, which is crucial for coordinated activities in Industrial Internet of Things (IIoT) environments.
Innovation Solution
A method and apparatus for time synchronization in wireless communication systems that allocate resources in the time domain, enabling a network apparatus to select a user apparatus, estimate propagation time, and provide a message with an estimated arrival time to synchronize system times across user devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing time synchronization methods are used in wireless communication systems, then basic synchronization can be achieved, but sub-microsecond accuracy required for coordinated activities in IIoT environments cannot be attained
Solution Approach 1:
The network apparatus performs preliminary actions by estimating propagation time in advance and providing estimated arrival time information to user apparatuses before actual coordinated activities. This allows user apparatuses to prepare their timing in advance, achieving sub-microsecond synchronization accuracy without requiring complex real-time coordination protocols.
Solution Approach 2:
The patent introduces an intermediary mechanism where the network apparatus acts as a mediator between time sources and user apparatuses. By providing estimated arrival time information through the communication system, the network enables precise time synchronization across distributed IIoT devices without requiring direct peer-to-peer synchronization, thus improving both accuracy and reliability.
2Measurement precision
If additional hardware or specific features are added at user apparatuses to achieve precise time synchronization, then sub-microsecond accuracy can be achieved, but device complexity and cost increase
Solution Approach 1:
The user apparatuses perform self-service by using their existing received signal strength information and the estimated arrival time provided by the network apparatus to automatically calculate and adjust their local timing. This eliminates the need for additional hardware or complex synchronization features at user devices, achieving sub-microsecond accuracy through software-based timing adjustment using available resources.
Solution Approach 2:
The patent makes the time synchronization mechanism universal by utilizing existing communication resources and signal strength measurements that are already available in wireless systems. The estimated arrival time information can be conveyed through standard message protocols, making the solution applicable to existing IIoT devices without requiring specialized hardware or features.
3Measurement precision
If propagation time estimation is performed for each user apparatus, then accurate arrival time prediction can be achieved, but processing time and system resources are consumed
Solution Approach 1:
The network apparatus performs partial propagation time estimation by using received signal strength information that is already available from existing communications. Rather than performing complete propagation measurements for each user apparatus, the system utilizes partial information (signal strength) combined with the allocated time resources to achieve sufficient accuracy for sub-microsecond synchronization without excessive processing time.
Solution Approach 2:
The patent changes the parameter used for propagation time estimation from traditional time-based measurements to signal strength-based estimation. By using received signal strength information combined with allocated time resources, the system achieves accurate arrival time prediction while reducing processing time, as signal strength data is already available from existing communication protocols.
Data Source
AI summary
The present subject matter relates to an apparatus for time synchronization in a wireless communication system using resources which are allocated in time domain for a set of user apparatuses of the wireless communication system. The apparatus comprises means being configured for: selecting a user apparatus of the set of user apparatuses; using the allocated resources for selecting a scheduled transmission time for the selected user apparatus; estimating a propagation time of a message from the apparatus to the selected user apparatus; estimating an arrival time of the message at the selected user apparatus using the scheduled transmission time and the propagation time; providing according to the scheduled transmission time a message including the estimated arrival time.