Wireless LAN Sounding Procedure Frame Transmission
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Solution Overview
Problem
In wireless local area networks (WLANs), the existing methods for frame transmission based on sounding procedures lack efficiency due to inadequate timing alignment between acquiring feedback information and transmitting frames, leading to performance deterioration and reduced throughput.
Innovation Solution
A method and apparatus where an access point (AP) transmits a null data packet announcement (NDPA) frame to multiple stations (STAs), followed by a null data packet (NDP), and receives feedback frames containing channel state information, allowing for the transmission of downlink frames based on this information within a specific time, optimizing channel state utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the AP transmits downlink frames after a long interval following feedback reception, then STAs have sufficient time to process and transmit feedback, but channel state information becomes outdated leading to performance deterioration
Solution Approach 1:
The patent applies preliminary action by having STAs transmit feedback frames in advance before the AP transmits downlink frames. The feedback frames are transmitted on uplink orthogonal frequency division multiplexing (OFDM) resources prior to the downlink transmission, ensuring that channel state information is fresh and accurate when needed for downlink frame transmission.
2Productivity
If the AP uses traditional timing for frame transmission after feedback, then processing simplicity is maintained, but throughput is reduced due to outdated channel state information
Solution Approach 1:
The patent implements a refined feedback mechanism where STAs transmit feedback frames containing channel state information on specifically allocated uplink OFDM resources. The AP uses this feedback information to determine transmission parameters for downlink frames, creating a closed-loop system that optimizes throughput through accurate channel state utilization.
3Productivity
If feedback frames are transmitted simultaneously by multiple STAs, then resource utilization is improved, but interference and collision increase
Solution Approach 1:
The patent segments the feedback transmission resources by allocating different uplink OFDM resources to different STAs. This segmentation allows multiple STAs to transmit feedback frames simultaneously without interference, as each STA uses its designated time-frequency resource allocation. The AP receives these segmented feedback transmissions and integrates the channel state information for downlink transmission decisions.
Data Source
AI summary
A method and apparatus for transmitting a frame on the basis of a sounding procedure is disclosed. The method for transmitting the frame on the basis of a sounding procedure in a wireless LAN may comprise the steps of: transmitting an NDPA frame to each of multiple STAs by an AP wherein the NDPA frame notifies of the transmission of NDP; transmitting the NDP to each of the multiple STAs by the AP; receiving, by the AP, multiple feedback frames transmitted through multiple transmission sources allocated to the multiple STAs in time sources overlapped by the multiple STAs, respectively; and transmitting, by the AP, multiple downlink frames to the multiple STAs respectively.