Group ACK Bitmap for Wireless Duty Cycle Compliance
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Solution Overview
Problem
In wireless communication networks, especially those with transmit duty cycle restrictions, the overhead of transmitting separate acknowledgments (ACKs) to multiple devices can exceed allowed transmission limits, such as 100 seconds per hour in certain European frequency bands, making it impractical for devices like sensors to send ACKs without violating duty cycle restrictions.
Innovation Solution
Implementing a 'group ACK' system where a single acknowledgment message, containing indicators for multiple devices, is transmitted using a single PHY header, reducing the overall data transmission and bandwidth usage, and allowing devices to acknowledge received communications efficiently within the limited transmission window.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate ACKs are transmitted to each device, then communication reliability is improved, but transmission overhead increases beyond duty cycle restrictions
Solution Approach 1:
The patent combines multiple individual ACK transmissions into a single group ACK message that acknowledges receipts from multiple devices simultaneously. This merging approach reduces the total number of transmissions required while maintaining the ability to individually acknowledge each device's message, thereby reducing overhead from 100+ separate ACKs to a single group ACK transmission.
Solution Approach 2:
The group ACK message serves multiple functions simultaneously: it acknowledges receipt of messages from multiple different devices in a single transmission, provides individual acknowledgment status for each device, and operates within the duty cycle restrictions. This multi-functionality allows the system to maintain reliable communication acknowledgment while adhering to transmission limits.
2Reliability
If individual ACKs are sent to multiple devices, then each device's receipt confirmation is ensured, but bandwidth consumption increases
Solution Approach 1:
Multiple individual ACK transmissions are merged into a single group ACK message that contains acknowledgment information for multiple devices. This consolidation reduces bandwidth consumption by eliminating redundant transmission headers and payload data that would be present in separate ACK messages, while still providing individual receipt confirmation for each device.
3Reliability
If separate ACK transmissions are used, then individual device acknowledgment is achieved, but power consumption increases
Solution Approach 1:
The patent merges multiple separate ACK transmissions into a single group ACK transmission, thereby reducing the total number of times devices need to activate their transmitters. Since wireless transmission is a high-power operation, reducing the number of transmission events from potentially 100+ individual ACKs to a single group ACK significantly reduces power consumption while maintaining individual acknowledgment capability through the grouped response.
4Adaptability or versatility
If ACK overhead is reduced through group acknowledgments, then duty cycle compliance is improved, but system complexity increases
Solution Approach 1:
The group ACK message is segmented to include individual acknowledgment indicators for each device, allowing the system to maintain simple individual device tracking while achieving compliance with duty cycle restrictions. Each device can independently process its own acknowledgment status from the grouped message without requiring complex inter-device coordination, thus managing system complexity effectively.
Data Source
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AI summary
Systems, methods, and devices for acknowledging communications from a plurality of devices are described herein. In some aspects, a group ACK includes a bitmap indicating whether a communication has been received from each of a plurality of apparatuses within a previous period. The previous period may comprise a time period since a previous ACK. In some aspects, group ACKs are transmitted pursuant to a schedule. For example, group ACKs may be transmitted a scheduled time after transmitting a beacon. In some aspects, a bitmap indicating whether a communication has been received from each of a plurality of apparatuses within a previous period may be transmitted in a beacon.