Multi-Link PPDU Trigger Frame Timing for Carrier Sensing
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Solution Overview
Problem
Existing communication technologies face challenges in managing simultaneous transmit and receive operations on multiple frequency bands due to interference, particularly when a PPDU carrying a trigger frame is sent, as conventional solutions are not applicable in scenarios where the sending device sends a PPDU with a trigger frame.
Innovation Solution
A communication method where a sending device sends a first PPDU with a trigger frame over one link and a second PPDU over another link, with the end time of the second PPDU constrained to ensure the receiving device can perform carrier sensing within a Short Interframe Space (SIFS) time before returning a TB PPDU.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a sending device sends a PPDU carrying a trigger frame over one link and a second PPDU over another link simultaneously, then the throughput is improved, but the receiving device cannot successfully implement carrier sensing due to interference
Solution Approach 1:
The patent segments the transmission by dividing it into two separate links (first link and second link) with different frequency bands. The trigger frame is sent over the first link while the second PPDU is sent over the second link, allowing independent handling of each transmission path and avoiding mutual interference that would occur in a single-link system.
Solution Approach 2:
The patent introduces a frequency dimension by using different frequency bands for the first link and second link. This dimensional separation allows simultaneous transmissions on different frequency planes, enabling the receiving device to perform carrier sensing on the first link without being blocked by transmissions on the second link.
2Adaptability or versatility
If the frequency spacing between multiple frequency bands is small, then the device can operate on multiple bands, but energy leakage from one band blocks receiving signals on another band
Solution Approach 1:
The patent segments the communication into separate links operating on different frequency bands. By assigning the trigger frame transmission to one link and the data transmission to another link with sufficient frequency spacing, the system maintains multi-band operation while minimizing energy leakage interference between bands.
Solution Approach 2:
The patent introduces a time interval constraint as an intermediary mechanism. By requiring that the second PPDU end time falls within a specific range relative to the trigger frame end time (calculated using SIFS and turnaround time), the system mediates the interaction between multi-band transmissions to prevent interference.
3Productivity
If the sending device sends a PPDU carrying a trigger frame, then the receiving device can respond with a TB PPDU, but the conventional solution is not applicable and carrier sensing fails
Solution Approach 1:
The patent applies preliminary action by pre-calculating the valid time range for the second PPDU end time based on the trigger frame end time, SIFS, and turnaround time. This preliminary determination of timing constraints ensures that when the receiving device needs to perform carrier sensing, the channel will be clear, thus enabling successful carrier sensing implementation.
Solution Approach 2:
The patent changes the timing parameter of the second PPDU transmission by constraining its end time to fall within a specific range [first time, second time] relative to the trigger frame. This parameter adjustment ensures that the second PPDU does not interfere with the receiving device's carrier sensing period, thereby enabling successful operation.
Data Source
AI summary
This application provides a communication method and a communication apparatus. In one example, a first physical layer protocol data unit (PPDU) is sent over a first link, where the first PPDU carries a trigger frame. A second PPDU is sent over a second link. An end time of sending the second PPDU is not earlier than a first time and not later than a second time, the first time is related to an end time of sending the first PPDU and a state turnaround time, and the second time is related to the end time of sending the first PPDU and a short interframe space (SIFS) time.