Adaptive Frequency Hopping With Dual ACK Bits for Cycle Reliability
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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, where traditional acknowledgement mechanisms fail to confirm successful packet transmission even if the data is received, leading to cycle errors.
Innovation Solution
The introduction of additional acknowledgement bits (current and previous acknowledgment bits) and an adaptive frequency hopping mechanism that dynamically allocates channels based on performance metrics, using a greedy algorithm to optimize packet error rate across cycles, and a last resort frequency mechanism to switch to better performing channels in case of transmission failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional acknowledgement mechanisms are used in wireless communication, then the protocol complexity is low, but the reliability of critical data delivery deteriorates under adverse conditions like fading channels and interference
Solution Approach 1:
The patent segments the acknowledgement mechanism into multiple independent acknowledgement bits, each corresponding to different packets or transmission attempts. This allows the system to track individual packet delivery status separately, improving reliability by identifying which specific packets need retransmission without requiring complex overall protocol changes.
Solution Approach 2:
The patent implements preliminary actions by sending multiple acknowledgement bits in advance along with data packets, indicating the expected acknowledgement status before actual transmission completion. This allows the receiving end to prepare for potential retransmissions and manage buffer resources proactively, improving delivery reliability under adverse conditions.
2Reliability
If frequency hopping is used to avoid interference, then the robustness against interference improves, but the packet error rate becomes uneven across different cycles
Solution Approach 1:
The patent implements feedback mechanisms where the system monitors packet error rates across different frequency channels and transmission cycles. Based on this feedback, the frequency hopping sequence is dynamically adjusted to distribute packets more evenly across channels with better performance, equalizing the packet error rate across cycles while maintaining interference resistance.
Solution Approach 2:
The patent makes the frequency hopping pattern dynamic by adapting it based on observed channel conditions and error rates. Instead of using a fixed hopping sequence, the system adjusts which frequencies are used in each cycle based on real-time performance data, thereby equalizing error rates while maintaining robustness against interference.
3Reliability
If multiple retransmissions are attempted to ensure delivery, then the packet delivery reliability improves, but the latency increases
Solution Approach 1:
The patent sends multiple acknowledgement bits in advance with each data packet, indicating the delivery status of multiple packets. This preliminary action allows the receiving end to identify and buffer packets that need retransmission without waiting for separate acknowledgement cycles, reducing the time penalty associated with multiple retransmissions while maintaining high delivery reliability.
4Adaptability or versatility
If a fixed frequency allocation is used, then the device complexity is low, but the adaptability to changing channel conditions deteriorates
Solution Approach 1:
The patent implements dynamic frequency allocation where the system adapts its frequency hopping pattern based on observed channel conditions and packet error rates. The frequency assignment changes dynamically across transmission cycles to optimize performance, providing adaptability to changing conditions without requiring complex real-time frequency selection algorithms.
Solution Approach 2:
The patent changes the frequency parameter dynamically by adjusting which frequencies are used for transmission in each cycle based on performance metrics. This parameter change approach allows the system to adapt to changing channel conditions by shifting operations to frequencies with better performance, balancing adaptability with manageable complexity.
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.