Mixed Bandwidth Station Sounding via Wide NDP
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Solution Overview
Problem
Current Wi-Fi technologies, such as IEEE 802.11ax, are inefficient in sounding multiple stations with mixed operating bandwidths, as they require individual sounding of each station with a smaller bandwidth, leading to increased overhead and complexity for access points.
Innovation Solution
Implementing a method using a null data packet (NDP) with a wider bandwidth than the stations, allowing for grouping of stations with mixed operating bandwidths in a single sounding sequence, and transmitting a null data packet announcement (NDPA) to request partial bandwidth channel feedback, followed by a beamforming report poll (BFRP) to facilitate steered OFDMA transmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If individual sounding is performed for each station with smaller bandwidth, then channel feedback accuracy for each station is improved, but overhead and complexity for access points increases
Solution Approach 1:
The patent combines multiple individual sounding operations into a single group sounding operation. Stations with different bandwidth capabilities (20 MHz, 40 MHz, 80 MHz) are grouped together and sounded simultaneously using a unified wide bandwidth NDP, eliminating the need for separate sounding sequences for each station and reducing access point complexity.
Solution Approach 2:
The wide bandwidth NDP serves multiple functions simultaneously: it provides sounding for stations of various bandwidth capabilities, carries NDPA information for multiple stations, and enables partial bandwidth feedback collection. This universal sounding mechanism replaces multiple specialized sounding operations.
2Loss of information
If individual sounding is performed for each station with smaller bandwidth, then channel feedback is obtained for each station, but time efficiency decreases due to increased overhead
Solution Approach 1:
Multiple sounding operations are merged into a single time-efficient group sounding sequence. The access point transmits one wide bandwidth NDP that simultaneously sounds all grouped stations, and collects feedback from multiple stations in parallel, dramatically reducing the total time required compared to sequential individual sounding.
Solution Approach 2:
The NDPA frame is transmitted in advance to announce the upcoming NDP and specify which stations should provide feedback. This preliminary action allows stations to prepare for feedback transmission, enabling efficient coordinated feedback collection immediately after the NDP, thereby minimizing overall sounding time.
3Productivity
If wide bandwidth NDP is transmitted to stations with smaller operating bandwidth, then bandwidth efficiency is improved, but compatibility with narrow bandwidth stations becomes challenging
Solution Approach 1:
Each station processes only the portion of the wide bandwidth NDP that corresponds to its operating bandwidth. A 20 MHz station processes only the 20 MHz portion, a 40 MHz station processes the 40 MHz portion, and so on. This local processing approach allows wide bandwidth transmission while maintaining compatibility with narrow bandwidth stations.
Solution Approach 2:
Stations perform partial processing of the wide bandwidth NDP, extracting only the relevant portion for their operating bandwidth. This partial action approach allows the system to transmit excessive bandwidth (wide NDP) while stations only process what they need, achieving both bandwidth efficiency and compatibility.
4Device complexity
If stations are grouped in one sounding sequence with wide bandwidth NDP, then overhead is reduced, but feedback collection from mixed bandwidth stations becomes complex
Solution Approach 1:
The feedback collection process is customized for each station based on its bandwidth capability. The access point requests partial bandwidth feedback specifically tailored to each station's operating bandwidth (20 MHz, 40 MHz, or 80 MHz), ensuring that each station provides appropriately sized feedback without requiring complex handling of full wide bandwidth feedback from all stations.
Solution Approach 2:
The NDPA frame includes explicit feedback requests that specify which stations should provide feedback and what bandwidth of feedback is expected. This structured feedback mechanism ensures that the access point receives the correct amount of feedback from each station, simplifying the overall feedback collection process despite mixed bandwidth capabilities.
Data Source
AI summary
Various embodiments relate to a method of sounding a plurality of stations (STAs) with mixed operating bandwidths using a null data packet (NDP), wherein the bandwidth of the NDP is wider than the bandwidth of one STA, including: grouping STAs of mixed operating bandwidth in one sounding sequence by a beamformer; transmitting a null data packet announcement (NDPA) to the STAs, wherein the NDPA indicates the requested partial bandwidth channel feedback for each STA by the beamformer; transmitting the wide-bandwidth NDP to the STAs by the beamformer; transmitting beamforming report poll (BFRP) frame to the STAs to trigger uplink transmission of channel feedback reports by the beamformer; and receiving by the beamformer a partial bandwidth channel feedback within the STA's operating bandwidth from the STAs; receiving and parsing channel feedback reports from the STAs used for following steered OFDMA transmissions by the beamformer.