WLAN Channel Sounding Feedback Segmentation
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Solution Overview
Problem
The next-generation WLAN system faces inefficiencies and reliability issues in channel sounding due to the need for longer channel access times and potential interference during feedback information transmission, especially with the increased channel bandwidth and MU-MIMO transmission scheme, leading to potential discarding of entire feedback information when interference occurs.
Innovation Solution
A channel sounding method that initiates with a null data packet announcement (NDPA) frame, followed by transmitting null data packets and receiving feedback frames split into segment frames, allowing for identification of missed segments and retransmission requests, thereby improving resource usage and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the channel bandwidth is increased and MU-MIMO transmission scheme is employed to support higher throughput, then the data processing rate is improved, but the amount of feedback information increases requiring longer channel access time which leads to higher probability of interference and feedback information loss
Solution Approach 1:
The feedback information is divided into multiple segments (first feedback segment, second feedback segment, etc.) that can be transmitted separately. Each segment is independently identifiable through segmentation indication fields, allowing the receiver to process and utilize available segments even if others are lost during transmission.
2Productivity
If the channel bandwidth is increased and MU-MIMO transmission scheme is employed, then the data processing rate is improved, but the probability of interference during feedback transmission increases leading to discarding of entire feedback information
Solution Approach 1:
By segmenting feedback information into multiple independent parts with identification fields, the system ensures that loss of one segment does not compromise the entire feedback. The receiver can identify and process successfully received segments while requesting retransmission of lost ones.
Solution Approach 2:
The system enables discarding of only the lost feedback segments while recovering and utilizing the successfully received segments. The receiver identifies missing segments through segmentation indication fields and requests selective retransmission, rather than discarding all feedback information.
3Measurement precision
If the amount of feedback information is increased to support wider channel bandwidth and MU-MIMO, then the channel information accuracy is improved, but the transmission time is extended increasing resource usage inefficiency
Solution Approach 1:
Feedback information is segmented into multiple parts that can be transmitted in parallel or sequentially. The segmentation indication fields allow the receiver to process available segments immediately, improving resource utilization while maintaining comprehensive channel information accuracy through complete segment collection.
Data Source
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AI summary
A channel sounding method in a wireless local area network (WLAN) system is provided. The method, performed by a transmitter, includes transmitting a null data packet announcement (NDPA) frame to a receiver to initiate a channel sounding procedure; transmitting a null data packet (NDP) to the receiver and receiving a feedback frame. The feedback frame includes a plurality of segment frames and a channel feedback report. The channel feedback report is split into a plurality of feedback segments. Each of the plurality of feedback segments is respectively included in each of the plurality of segment frames. The each of the plurality of segment frames includes a first-segment subfield indicating whether the each of the plurality of feedback segment included is a first segment and a remaining-segment subfield indicating the number of remaining feedback segments.