IoT Service Layer Time Synchronization via Intermediary Mediation
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Solution Overview
Problem
Existing time synchronization technologies, such as NTP, PTP, and GPS, are not ideal for resource-constrained IoT devices, leading to challenges in synchronizing time across multiple IoT entities, which is crucial for accurate timestamping and communication in IoT networks.
Innovation Solution
The proposed solution involves implementing time synchronization mechanisms within an IoT Service Layer (SL), including customizable SL beaconing, SL time advertising, SL time compensation, and SL-based network latency determination, to achieve end-to-end time synchronization across IoT devices, gateways, and cloud services.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing time synchronization technologies (NTP, PTP, GPS) are used, then time synchronization capability is provided, but resource consumption increases and precision deteriorates for resource-constrained IoT devices
Solution Approach 1:
The patent introduces a Service Layer as an intermediary between IoT devices and existing time synchronization systems. The Service Layer receives time synchronization requests from resource-constrained devices, performs the actual time synchronization using NTP/PTP/GPS, and returns synchronized time information to devices. This mediator approach allows devices to benefit from precise time synchronization without directly implementing resource-intensive synchronization protocols.
Solution Approach 2:
The Service Layer creates a simplified copy of time synchronization functionality tailored for resource-constrained devices. Instead of requiring devices to implement full NTP/PTP client stacks, the Service Layer provides a lightweight interface that copies essential time synchronization capabilities, reducing memory and processing requirements while maintaining synchronization precision.
2Reliability
If existing time synchronization technologies are implemented on resource-constrained devices, then time synchronization is achieved, but device complexity increases
Solution Approach 1:
The Service Layer acts as an intermediary that handles the complexity of time synchronization protocol implementation, authentication, and server communication. Devices only need to interact with the simplified Service Layer interface, which manages all complex operations including protocol selection, timestamp generation, and synchronization state maintenance, thereby reducing device complexity while ensuring reliable synchronization.
Solution Approach 2:
The Service Layer provides universal time synchronization services that work across multiple device types and scenarios. A single Service Layer implementation supports various synchronization protocols (NTP, PTP, GPS), multiple time formats, and different application requirements, eliminating the need for each device to implement multiple specialized synchronization functions.
3Measurement precision
If NTP protocol is used for time synchronization, then time synchronization within a few milliseconds of UTC is achieved, but synchronization accuracy deteriorates over public Internet connections
Solution Approach 1:
The Service Layer dynamically selects between different time synchronization protocols (NTP, PTP, GPS) based on network conditions and device capabilities. When connected to local networks with PTP servers, it uses PTP for microsecond precision; when using public Internet NTP servers, it applies compensation algorithms and selects optimal servers to maintain the best possible precision under varying conditions.
Solution Approach 2:
The Service Layer implements feedback mechanisms that monitor synchronization quality and adjust synchronization behavior accordingly. It tracks time offset variations, network latency, and synchronization accuracy, using this feedback to select optimal NTP servers, adjust polling intervals, and apply compensation algorithms to maintain reliable synchronization despite public Internet connection variability.
Data Source
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AI summary
Methods and systems may be used to synchronize time across multiple IoT related entities, such as a network of resource constrained sensor and actuator type devices, IoT gateways, IoT cloud services, or IoT applications.