Uplink Beamforming Trigger Frame Mechanism for WLAN Throughput
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Solution Overview
Problem
Current WLAN systems, particularly those based on the 802.11 standards, lack efficient uplink beamforming capabilities, which limits the throughput and efficiency of uplink transmissions.
Innovation Solution
The implementation of an apparatus and method for uplink beamforming in WLAN systems, involving the transmission of trigger frames and feedback frames to facilitate the generation of a beam steering matrix, enabling the transmission of beamformed physical layer protocol data units (PPDUs).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If uplink beamforming is not implemented in WLAN systems, then the system maintains simplicity and compatibility with existing 802.11 standards, but uplink throughput and transmission efficiency are limited
Solution Approach 1:
The system performs preliminary channel sounding by transmitting NDP frames before actual data transmission. The access point sends trigger frames requesting sounding NDPs from stations, collects channel state information, and generates feedback frames with beam steering matrix information in advance, preparing the beamforming parameters before uplink data transmission occurs
Solution Approach 2:
The system implements a feedback mechanism where the access point receives sounding NDPs from stations, processes the channel state information, and sends back feedback frames containing beam steering matrices. This feedback enables stations to adjust their uplink transmission beams based on received signal quality, creating a closed-loop beamforming system that improves uplink throughput
2Reliability
If beamforming is implemented on both uplink and downlink channels, then communication performance and interference reduction are improved, but the complexity of frame structure and signaling increases
Solution Approach 1:
The trigger frame structure is designed to serve multiple functions: it requests sounding NDPs from stations, carries resource allocation information, and initiates the beamforming process. The feedback frame similarly serves multiple purposes by carrying beam steering matrices, channel state information, and acknowledgment data, reducing the need for separate dedicated frames for each function
Solution Approach 2:
The beam steering matrix information is nested within the feedback frame structure, which itself is nested within the overall trigger frame sequence. The feedback frame contains the beam steering matrix as a component element, allowing the complex beamforming information to be organized hierarchically within the existing frame structure rather than requiring separate independent frames
Data Source
AI summary
A method for a first device to communicate with at least one second device in a wireless local area network (WLAN) system includes providing a first trigger frame to at least one second device, the first trigger frame requesting at least one sounding null data packet (NDP), providing a feedback frame to the at least one second device, the feedback frame including feedback information generated based on the at least one sounding NDP, and providing a second trigger frame to the at least one second device, the second trigger frame requesting at least one beamformed physical layer protocol data unit (PPDU), each of the first trigger frame and the feedback frame including a sounding dialog token number field having a sounding sequence number.