PPDU Extension for Mid-Transmission Retransmission Latency
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Solution Overview
Problem
Existing wireless communication protocols experience unnecessary delays and increased latency due to the requirement for transmitting acknowledgment frames only after the completion of a PPDU transmission, especially in scenarios involving multiple frequency bands, which is unsuitable for latency-sensitive traffic.
Innovation Solution
Implementing a mechanism that allows for the transmission of acknowledgment frames, such as XACK, during the ongoing PPDU transmission, enabling immediate retransmission of erroneous frames without full preambles, and utilizing extensions of PPDU without interframe spacing to reduce latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If acknowledgment frames are transmitted only after PPDU completion, then protocol simplicity is maintained, but retransmission latency increases
Solution Approach 1:
The receiver performs preliminary actions by detecting errors and preparing acknowledgment frames during the ongoing PPDU transmission, rather than waiting for completion. This allows the transmitter to receive NACKs mid-transmission and immediately initiate retransmission, reducing latency while maintaining manageable protocol complexity through structured error detection and acknowledgment mechanisms.
Solution Approach 2:
The patent enables continuous useful action by allowing acknowledgment frame transmission during the PPDU transmission period. The transmitter can receive NACKs and send retransmission frames without waiting for the original PPDU to complete, creating overlapping transmission cycles that minimize idle time and reduce overall retransmission latency.
2Productivity
If full preambles are transmitted for each retransmission, then protocol compatibility is maintained, but transmission overhead increases
Solution Approach 1:
The patent extracts and removes the redundant full preamble from subsequent retransmission frames. By identifying that the receiver already has channel state information from the initial PPDU transmission, the system transmits only the essential data portion for retransmission, eliminating unnecessary preamble overhead while maintaining protocol compatibility through selective framing.
Solution Approach 2:
For retransmission frames, the patent applies partial action by transmitting only the necessary data portion rather than the complete frame with full preamble. This partial transmission approach reduces overhead and energy consumption while maintaining sufficient information for the receiver to correctly process and acknowledge the retransmitted data.
3Loss of time
If interframe spacing is maintained between PPDUs, then protocol stability is ensured, but latency-sensitive traffic performance deteriorates
Solution Approach 1:
The patent introduces dynamic adjustment of interframe spacing based on transmission conditions. When error-free transmission is detected, the system dynamically reduces or eliminates interframe spacing to minimize latency for latency-sensitive traffic. When stability concerns arise, the protocol dynamically increases spacing to maintain protocol stability, creating an adaptive balance between speed and stability.
Solution Approach 2:
The system changes the interframe spacing parameter dynamically based on transmission success and network conditions. By adjusting this critical parameter in real-time, the protocol can optimize performance for latency-sensitive traffic when conditions permit while maintaining stability when necessary, resolving the contradiction between speed and stability.
Data Source
AI summary
A first station (STA) receives from a second STA, while transmitting a first frame to the second STA, a second frame indicating a payload unit, of the first frame, received in error by the second STA. The first STA transmits to the second STA, an extension of the first frame comprising the payload unit received in error by the second STA.