Zigbee Router Buffering for Duplicate Fragment Suppression
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Solution Overview
Problem
The Zigbee protocol experiences significant communication overhead and power consumption due to redundant data exchanges and unnecessary re-transmissions of fragmented data packets, particularly in battery-powered 'sleepy' end devices, which frequently poll for data packets, leading to increased network traffic and energy waste.
Innovation Solution
A Zigbee router device is configured to intercept and manage data packets on behalf of the end device, decrypting and analyzing network layer payloads to identify re-transmitted data blocks, dropping duplicates, and sending acknowledgments on behalf of the end device, thereby reducing redundant communications and optimizing the fragmentation window.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the ZED frequently polls for data packets to ensure timely data reception, then data delivery reliability is improved, but power consumption increases
Solution Approach 1:
The parent router acts as an intermediary between the source device and the ZED. It intercepts data packets intended for the ZED, stores them in its buffer, and manages their delivery. This allows the ZED to sleep longer without polling, as the parent router proactively pushes data when the ZED wakes up, reducing the frequency of polling operations and thus lowering power consumption while maintaining reliable data delivery
Solution Approach 2:
The parent router performs preliminary actions by pre-receiving and buffering data packets before the ZED needs them. When the ZED wakes up from sleep mode, the data is already available in the parent router's buffer, eliminating the need for the ZED to actively poll for data. This preliminary data preparation reduces the ZED's active time and power consumption while ensuring data is ready for immediate delivery
2Reliability
If the ZED sends acknowledgments for each received data packet, then transmission reliability is improved, but communication overhead increases
Solution Approach 1:
The patent merges multiple acknowledgment functions into a single acknowledgment message. Instead of the ZED sending separate ACKs for each data packet received, the parent router consolidates the acknowledgment process. The ZED sends one acknowledgment that covers multiple data packets, significantly reducing the number of communication exchanges while maintaining transmission reliability through the parent router's buffer management
3Productivity
If the parent router buffers and manages data packets proactively, then communication efficiency is improved, but device complexity increases
Solution Approach 1:
The parent router serves as an intermediary with enhanced buffering capabilities. It intercepts data packets from source devices, stores them in its buffer memory, and manages their delivery to ZEDs. This intermediary role with buffering capability streamlines communication by eliminating the need for frequent ZED polling and reducing acknowledgment overhead, thereby improving communication efficiency while the increased buffering functionality is already inherent to router devices
Solution Approach 2:
The parent router performs self-service by autonomously managing data packet buffering, tracking, and delivery without requiring complex coordination with the ZED. The router independently handles data interception, buffer management, and proactive delivery, simplifying the overall system operation while improving communication efficiency through intelligent local decision-making
Data Source
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AI summary
A method for delivering data frames from a source device (602) to a Zigbee end device, ZED, (550) via a Zigbee router device, ZR, (510), comprises, at the ZR, receiving (605), a data request and at least one data block (615) from a transmission window of a plurality of data blocks from the source device (602), and placing the received data block in a queue for transmission; receiving (609) a data request from the ZED; transmitting, the received data block from the queue, to the ZED and receiving an acknowledgement from the ZED. The method further includes receiving a re-transmission of the transmission window of the data blocks (625, 630, 635) from the source device (602); and dropping, at least one re-transmitted data block (630), previously received and transmitted by the ZR, and transmitting, by the ZR, the remaining re-transmitted data block(s) (625, 635), to the ZED.