OFDMA Wireless Industrial Communication with Interleaved Sub-Carriers
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Solution Overview
Problem
Existing wireless communication systems are not suitable for real-time industrial applications due to susceptibility to electromagnetic interference and inability to meet strict latency and reliability requirements, particularly in industrial automation systems.
Innovation Solution
A wireless communication system utilizing orthogonal frequency division multiple access (OFDMA) with a master wireless node and slave wireless nodes, employing interleaved orthogonal sub-carriers, beacon frames for synchronization, and a reduced preamble sequence with high- and low-correlation symbols to enhance reliability and reduce false detection of spurious transmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wired communication is used to achieve real-time communication, then reliability and latency requirements are met, but electromagnetic interference from high voltage currents affects performance
Solution Approach 1:
The patent replaces wired mechanical/physical connections with wireless communication technology. Specifically, it uses wireless local area network (WLAN) protocols to substitute for traditional wired industrial communication, thereby eliminating the harmful electromagnetic interference that affects wired cables while maintaining real-time communication capabilities through protocol optimizations
2Ease of manufacture
If existing wireless communication systems are used, then installation is cleaner and easier, but strict latency and reliability requirements cannot be met
Solution Approach 1:
The patent changes key communication parameters to meet real-time requirements. It implements fixed transmission intervals, predetermined time limits for message delivery, and optimized packet structures that guarantee latency bounds. These parameter changes enable the wireless system to achieve industrial-grade reliability while maintaining installation simplicity
3Reliability
If OFDM systems with QoS enhancements are used, then soft-real-time requirements are supported, but hard real-time requirements and strict latency constraints cannot be satisfied
Solution Approach 1:
The patent segments the communication protocol into distinct layers and functions, with separate handling for timing-critical data versus non-critical data. It divides transmission into fixed time slots and uses dedicated protocols for different message types, allowing hard real-time requirements to be met for critical communications while maintaining soft real-time support for other data
4Adaptability or versatility
If CDMA techniques are used in cellular networks, then wireless communication capability is provided, but protocol complexity and equipment cost increase
Solution Approach 1:
The patent adopts standardized, commercially available wireless communication hardware and protocols (such as WLAN standards) rather than custom complex systems. By using off-the-shelf wireless components with simplified protocols optimized for industrial applications, it reduces equipment cost and protocol complexity while maintaining wireless communication versatility
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AI summary
Methods for operating real-time wireless networks enable robust medium access strategies for communicating nodes in the network. A given wireless channel is divided into several sub-carriers, with each node assigned to a subset of sub-carriers. A master wireless node uses different subsets of the sub-carriers to communication with two or more slave wireless nodes simultaneously. The method includes generation of preambles that are robust to interference and multipath conditions. The method also enables communication within a maximum predetermined latency bound.