Wireless Packet Acknowledgment With Adaptive Frequency Hopping
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Solution Overview
Problem
Existing wireless communication systems, such as IO-Link Wireless, face challenges in ensuring reliable delivery of critical data due to adverse conditions like fading channels and interference, which can prevent successful acknowledgement and negative acknowledgement messages from being received, even if the data is successfully transmitted.
Innovation Solution
The introduction of additional acknowledgement bits, a novel adaptive frequency hopping mechanism, and a last resort frequency mechanism to improve transmission reliability. The adaptive frequency hopping table dynamically selects channels based on performance statistics, and the last resort mechanism switches to a better performing channel for the last subcycle in a cycle when previous attempts fail.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional acknowledgement mechanisms are used in wireless communication, then the system maintains simple protocol structure, but packet delivery reliability deteriorates under fading channels and interference
Solution Approach 1:
The patent segments the acknowledgement mechanism into multiple independent acknowledgement bits (ACK0, ACK1, ACK2, etc.) corresponding to different packets. Each bit independently indicates the reception status of a specific packet, allowing the receiver to provide granular feedback without requiring complex retransmission protocols. This segmentation enables reliable delivery by allowing selective retransmission of only failed packets while maintaining protocol simplicity.
Solution Approach 2:
The patent implements preliminary action by having the receiver store and track multiple packet reception states before transmitting acknowledgements. The receiver maintains a buffer of received packets and their corresponding ACK bits, preparing the feedback information in advance. This allows the system to handle out-of-order arrivals and fading channels proactively, ensuring that acknowledgement information is ready when needed without adding complex real-time processing requirements.
2Reliability
If multiple retransmissions are attempted to ensure reliable delivery, then packet delivery reliability improves, but latency increases
Solution Approach 1:
The patent implements self-service by enabling the receiver to autonomously manage packet buffering and acknowledgement generation without requiring complex coordination with the transmitter. The receiver independently tracks which packets were received successfully using the ACK bits and can request retransmission of specific failed packets. This self-managed approach reduces overhead and latency compared to traditional ARQ protocols by eliminating complex handshaking and allowing parallel processing of multiple packets.
3Reliability
If frequency hopping is used to avoid interference, then communication robustness improves, but system complexity and synchronization requirements increase
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the frequency hopping sequence based on channel conditions and packet transmission status. The system changes frequency parameters adaptively, selecting optimal frequencies for each packet transmission based on observed channel quality. This parameter adaptation provides robustness against fading and interference while maintaining relatively simple implementation through predefined frequency sequences that can be switched based on ACK feedback.
Data Source
AI summary
A novel and useful acknowledgement and adaptive frequency hopping mechanism for use in wireless communication systems such as IO-Link Wireless. One or two additional acknowledgement bits are added to packet transmissions. One is a current acknowledgment bit which indicates whether a packet was successfully received anytime during the current cycle. The second bit is a previous acknowledgment bit which indicates whether packets were received successfully anytime during the previous cycle. An adaptive hopping table is constructed using a greedy algorithm which chooses frequencies with the best PER for transmission of higher priority packets, while equalizing the PER products across cycles. A last resort frequency mechanism further improves transmission success by switching to a better performing channel for the last subcycle when previous attempts to transmit a high priority packet have failed.