Wireless TSN Frame Slotting for Deterministic Short-Cycle Communication
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Solution Overview
Problem
Existing WiFi technology is inefficient for transmitting small data packets with short cycles due to the overhead required by preambles, limiting the number of terminals that can be accommodated and failing to meet the deterministic low-latency requirements of industrial automation applications like closed-loop control and robot control.
Innovation Solution
A time division multiple access (TDMA) scheme is employed to divide frames into downlink and uplink sections, with simplified preambles and slot-based data transmission/reception, allowing frame aggregation for both uplink and downlink data, and using cyclical channel information to maintain accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional WiFi technology with preambles is used for data transmission, then data transmission can be performed with standard protocol support, but transmission efficiency deteriorates when data size is smaller than preamble size and short cycle transmission (e.g., 125 μs) cannot be satisfied
Solution Approach 1:
The patent segments the frame structure into distinct downlink and uplink sections, with the downlink section containing a preamble and multiple slots for different terminals. This segmentation allows the preamble to be shared across multiple terminals rather than requiring separate preambles for each terminal, thereby improving transmission efficiency when data size is small compared to preamble size.
Solution Approach 2:
The patent implements periodic action by organizing data transmission into fixed time slots within frames, where each terminal is assigned specific slots for uplink and downlink transmission. This periodic structure enables deterministic low-latency communication with short cycles (e.g., 125 μs) by ensuring that each terminal has guaranteed transmission opportunities at regular intervals.
2Reliability
If wired Ethernet-based TSN is used, then deterministic service with low latency and low delay variation is achieved, but deployment flexibility deteriorates in places where wired communication is difficult
Solution Approach 1:
The patent replaces the mechanical wired connection system with a wireless communication system that implements TSN principles. By substituting physical cable connections with wireless signals while maintaining the deterministic frame structure and time slot allocation, the system achieves both deployment flexibility in wireless environments and reliable deterministic service quality with low latency and low delay variation.
3Duration of action of moving object
If frame aggregation for uplink and downlink is implemented, then data transmission cycle is reduced to meet short cycle requirements, but system complexity increases
Solution Approach 1:
The patent merges uplink and downlink data transmissions into a single unified frame structure, where both directions of communication are aggregated within the same frame. This merging allows the system to meet short transmission cycle requirements by consolidating multiple transmissions into one frame, while the regular and predictable frame structure actually reduces processing complexity compared to handling separate frames for each direction.
Data Source
AI summary
The present invention relates to a method and apparatus for radio communication of a time sensitive network. The method includes dividing, by the first node, a frame into a downlink section and an uplink section, transmitting, by the first node, downlink data to at least one second node in units of slots in the downlink section, and receiving, by the first node, uplink data from the at least one second node in units of slots in the uplink period.