Inserted PPDU Latency Reduction in WiFi A-PPDU
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Solution Overview
Problem
WiFi systems introduce significant and variable latency, which can degrade the performance of latency-sensitive applications by requiring them to wait for the completion of data unit transmission before sending newly received packets.
Innovation Solution
A method and system that allow for the insertion of latency-sensitive packets into an ongoing Aggregated Physical layer Protocol Data Unit (A-PPDU) in a WiFi system, enabling these packets to be transmitted without waiting for the completion of the original data unit, while maintaining compatibility with legacy STAs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If a non-AP STA waits for the completion of an originally scheduled A-PPDU transmission before sending a new latency-sensitive packet, then the original data unit transmission is maintained, but latency for latency-sensitive applications increases significantly
Solution Approach 1:
The patent segments the A-PPDU structure by inserting a new PPDU within the data portion of the originally scheduled A-PPDU. The inserted PPDU occupies specific resource units (RUs) and time slots, allowing simultaneous transmission of original and new data without requiring complete transmission of the original A-PPDU first. This segmentation enables latency-sensitive packets to be transmitted promptly while maintaining the original transmission schedule for non-latency-sensitive data.
2Loss of energy
If the radio is kept on to monitor the completion of the originally scheduled A-PPDU, then transmission accuracy is maintained, but power consumption increases
Solution Approach 1:
The patent incorporates a start indication (such as a trigger frame or specific signal) in the preamble of the originally scheduled A-PPDU that预先 indicates the candidate start time of the inserted PPDU. This allows the non-AP STA to prepare in advance by tuning to the appropriate frequency and timing, enabling the radio to be turned off after receiving the inserted PPDU without missing critical transmission completion signals. The preliminary indication ensures reliable reception while minimizing power consumption.
3Productivity
If the inserted packet occupies the same frequency bandwidth as the original A-PPDU, then transmission efficiency is maximized, but interference between the original and inserted packets increases
Solution Approach 1:
The patent applies local quality by allocating the inserted PPDU to specific resource units (RUs) within the frequency spectrum, rather than requiring the entire bandwidth. Different RUs can be assigned to different users or data types, allowing the inserted latency-sensitive packet to occupy only the necessary frequency resources. This localized allocation reduces interference with the original A-PPDU transmission while maintaining efficient use of the available spectrum.
Data Source
AI summary
A system and method for managing latency in a wireless network. In some embodiments, the method includes: receiving, by a non-Access Point Station (non-AP STA), a first inserted packet; and sending, by the non-AP STA, an Acknowledgement (ACK) for the first inserted packet, the first inserted packet beginning after the beginning of a first originally scheduled Aggregated Physical layer Protocol Data Unit (A-PPDU) and being substituted for a portion of the data of the first originally scheduled A-PPDU.