Multi-User PPDU Probe Response for Wireless LAN Coverage
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Solution Overview
Problem
Current wireless LAN systems face challenges in increasing transmission coverage during initial access, particularly in dense environments with multiple access points and stations, leading to disparities in transmission ranges and reduced system performance.
Innovation Solution
The method involves an access point transmitting a trigger frame on a channel, receiving probe request frames from multiple stations on sub-channels, and responding with a Multi-User Physical Layer Protocol Unit (MU PPDU) that includes probe response frames, thereby increasing the transmission coverage of initial access frames and reducing disparities in transmission ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If traditional single-user transmission methods are used for initial access, then transmission coverage is limited, but system complexity remains low
Solution Approach 1:
The patent combines multiple probe response frames into a single MU PPDU transmission. The access point aggregates responses for multiple stations into one multi-user physical layer protocol unit, allowing simultaneous delivery to multiple stations. This merging approach extends transmission coverage by utilizing wider bandwidth resources while maintaining manageable system complexity through standardized aggregation procedures.
Solution Approach 2:
The patent transitions from single-user sequential transmission to multi-user parallel transmission by introducing the MU PPDU dimension. Instead of transmitting probe responses to each station sequentially on narrow bandwidth, the system uses wideband MU PPDU transmissions that accommodate multiple stations simultaneously, effectively expanding the transmission coverage area.
2Area of stationary object
If probe request frames are transmitted on narrow sub-channels, then transmission coverage is reduced, but frame collision probability decreases
Solution Approach 1:
The patent merges multiple narrow sub-channel transmissions into a single wideband MU PPDU transmission. By aggregating probe responses for multiple stations into one wideband transmission, the system achieves extended transmission coverage while the standardized aggregation timing and resource allocation mechanisms prevent frame collisions that would occur with simultaneous narrow channel transmissions.
3Area of stationary object
If multiple stations transmit probe request frames simultaneously on the same channel, then transmission coverage is maximized, but frame collision increases
Solution Approach 1:
The patent introduces the trigger frame as an intermediary that coordinates simultaneous probe request transmissions from multiple stations. The trigger frame is transmitted by the access point on a wide channel, prompting multiple stations to transmit their probe requests simultaneously. The access point then aggregates these requests and sends consolidated probe responses via MU PPDU, maintaining both wide transmission coverage and high initial access efficiency by preventing random collisions through coordinated transmission.
Data Source
AI summary
A method and an apparatus for increasing transmission coverage of an STA performing an initial access in a wireless LAN are disclosed. An initial access method in a wireless LAN can comprise the steps of: transmitting a trigger frame on a channel by an AP; receiving, by the AP, a first probe request frame transmitted on a first sub-channel by a first STA as a response to the trigger frame; and transmitting, by the AP, on the channel, an MU PPDU including a first probe response frame, which is a response to the first probe request frame, and a second probe response frame, which is a response to the second probe request frame, wherein the channel can include the first sub-channel and the second sub-channel.