Multi-STA Block Ack Frame Segmentation for WLAN Overhead Reduction
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Solution Overview
Problem
In the IEEE 802.11ax standards, the efficient transmission of acknowledgement signals in multi-user uplink scenarios is hindered by the increased overhead of multi-station block acknowledgement frames, which can lead to collisions and inefficiencies in wireless local area networks.
Innovation Solution
A method is proposed where an Access Point transmits a trigger frame to multiple stations, receives data, and sends acknowledgement signals through a Multi-STA Block Ack frame, limiting the number of stations per frame to a specific transmission unit time, and further transmits signals to stations not included in the initial frame, using a processor to manage and process these signals efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If a Multi-STA Block Ack frame is used to transmit acknowledgement signals to multiple stations, then the overhead is reduced, but the frame size increases causing transmission time to exceed specific time limits
Solution Approach 1:
The patent segments the acknowledgement process into multiple phases: first transmitting a Multi-STA Block Ack frame to multiple stations simultaneously, then transmitting individual Block Ack frames to stations that did not receive their acknowledgements in the first phase. This segmentation allows the system to reduce overhead for most stations while ensuring complete coverage within time constraints.
Solution Approach 2:
The patent applies partial action by transmitting acknowledgements to only a subset of stations in the first Multi-STA Block Ack frame, specifically limiting the number of stations to those whose acknowledgements can be transmitted within the specified time limit. Stations not included in this first batch receive acknowledgements in subsequent individual transmissions.
2Productivity
If acknowledgement signals are transmitted to all stations in a single Multi-STA Block Ack frame, then transmission efficiency is improved, but collisions may occur
Solution Approach 1:
The patent divides the acknowledgement transmission into multiple segments or batches. The first segment uses a Multi-STA Block Ack frame transmitted after a SIFS interval, and the second segment uses individual Block Ack frames transmitted after a DIFS interval. This segmentation reduces collision probability by spreading transmissions across different time slots with different contention conditions.
Solution Approach 2:
The patent implements periodic action by using different inter-frame spacing intervals (SIFS followed by DIFS) between the first and second acknowledgement transmissions. This periodic structure with varying intervals helps to manage channel access and reduce collisions in the wireless medium.
3Loss of substance
If the number of stations in a Multi-STA Block Ack frame is increased, then overhead is reduced, but the frame transmission time exceeds the specific transmission unit time
Solution Approach 1:
The patent applies dynamics by adaptively adjusting the number of stations included in the first Multi-STA Block Ack frame based on the specific transmission unit time constraint. The system dynamically determines which stations can be accommodated in the first batch and which require subsequent individual transmissions, optimizing the balance between overhead reduction and time constraints.
Solution Approach 2:
The patent implements partial action by transmitting acknowledgements to only a partial set of stations in the first Multi-STA Block Ack frame, specifically those that can be transmitted within the time limit. The remaining stations receive acknowledgements in subsequent individual transmissions, ensuring the time constraint is not violated while still achieving overhead reduction for the first batch.
Data Source
AI summary
The present document relates to a method for transmitting an acknowledgement/negative acknowledgement (ACK/NACK) signal for transmission data of a plurality of stations (STAs) by an access point (AP) in a wireless LAN (WLAN) system, and an apparatus therefor. To this end, the AP transmits a trigger frame to the plurality of STAs, and on receiving data from the plurality of STAs in response to the trigger frame, transmits ACK/NACK signals for the data received from the plurality of STAs through a multiuser block ACK frame (M-BA frame). Here, the M-BA frame includes ACK/NACK signals for STAs, the number of which is determined so as not to exceed a specific transmission unit time, among the ACK/NACK signals for the plurality of STAs, and the AP additionally transmits ACK/NACK signals to one or more STAs, to which ACK/NACK signals have not been transmitted through the M-BA, among the plurality of STAs.