WLAN Trigger Frame Signaling for Mixed EHT Uplink PPDU Types
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Solution Overview
Problem
Existing IEEE 802.11be EHT WLAN systems face challenges in efficiently triggering different types of physical layer protocol data unit (PPDU) transmissions due to the presence of HE and R1/R2 EHT stations, as R1 EHT stations do not support frequency domain aggregated PPDUs, necessitating an enhanced trigger frame to optimize throughput in large bandwidth environments.
Innovation Solution
An enhanced trigger frame is introduced with additional subfields to indicate the type of PPDU transmission, allowing for HE and R2 EHT stations to transmit HE TB PPDUs, EHT TB PPDUs, or TB FD-A-PPDUs, with specific bandwidth and resource unit allocations, ensuring orthogonal pre-modulated fields and backward compatibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a wireless device waits for an upcoming uplink slot to transmit buffered data, then the transmission can be scheduled, but the data remains silent for an extended period causing increased latency and potential data loss
Solution Approach 1:
The access point triggers uplink transmissions in advance by sending trigger frames before the actual data transmission occurs. This preliminary action allows the wireless device to prepare and transmit data at optimized times rather than passively waiting for the next scheduled slot, thereby reducing silence periods and improving reliability.
Solution Approach 2:
The system implements a feedback mechanism where the access point monitors buffer status reports from wireless devices and dynamically adjusts trigger frame transmissions accordingly. This feedback loop enables the system to respond to actual data needs and optimize transmission timing to minimize silence periods.
2Productivity
If the access point continuously monitors buffer status reports to trigger uplink transmissions, then transmission timing can be optimized, but the complexity of coordinating multiple wireless devices increases
Solution Approach 1:
The access point performs multiple functions through a single trigger frame mechanism: it monitors buffer status, determines optimal transmission times, and coordinates multiple wireless devices simultaneously. This multi-functional approach simplifies the overall system architecture while maintaining high productivity.
Solution Approach 2:
The wireless devices autonomously manage their own buffer status and transmission timing by responding to trigger frames based on their local conditions. This self-service mechanism reduces the coordination burden on the access point and simplifies the overall system complexity.
3Loss of time
If the wireless device transmits data immediately when ready, then transmission latency is reduced, but the access point cannot efficiently manage multiple devices and channel access conflicts increase
Solution Approach 1:
The access point sends trigger frames in advance to schedule uplink transmissions, allowing wireless devices to prepare their data and transmit at predetermined times. This preliminary scheduling eliminates the need for immediate transmission while preventing channel access conflicts through coordinated timing.
Solution Approach 2:
The system uses buffer status reports as feedback to dynamically adjust trigger frame transmissions. This feedback mechanism enables the access point to optimize transmission timing for each device while maintaining efficient channel access management across multiple devices.
Data Source
Figure 1A~1B
Figure 1C~1D
Figure 1E~1G
AI summary
Embodiments of the invention provide methods and apparatuses for triggering uplink transmission in wireless local area network (WLAN). The method for triggering uplink transmission comprises generating, by an access point (AP), a trigger frame based on a type of physical layer protocol data unit (PPDU) transmissions to be solicited from a plurality of stations (STAs) in the WLAN, wherein the trigger frame comprises a common information field including a first subfield indicating whether the trigger frame is a first type trigger frame or a second type trigger frame, and if the trigger frame is the second type trigger frame, the common information field further comprises a second subfield indicating the PPDU transmission type, and transmitting the trigger frame to the plurality of STAs. With the methods and apparatuses proposed by embodiments of the invention, the generated trigger frame may be used to solicit different types of uplink transmission in WLAN.