WLAN Feedback Tone Configuration for Low-Overhead MIMO Beamforming
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Solution Overview
Problem
The increased number of spatial streams in new WLAN standards like IEEE 802.11be requires improved signaling techniques for efficient feedback frame reception, particularly in multi-input multi-output (MIMO) beamforming, to optimize bandwidth utilization and reduce feedback overhead.
Innovation Solution
A method for configuring feedback tones for all or partial bands in the 802.11be wireless LAN system, using specific tone indices for 20 MHz and 40 MHz bands, which are set to [-122, -116, -108:32:−12, -4, 2, 4, 12:32:108, 116, 122] and [-244, -236:32:−12, -4, 4, 12:32:236, 244] respectively, to enhance the sounding procedure between the beamformer and beamformee.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If feedback tones are configured for all bands in new WLAN standards, then measurement precision of channel state information is improved, but feedback overhead increases
Solution Approach 1:
The patent segments the feedback tone configuration by band type (20 MHz, 40 MHz, 80 MHz) and applies different tone index patterns to different bands. This allows selective optimization where full-band feedback tones are configured only where necessary, rather than uniformly across all bands, thereby reducing overall feedback overhead while maintaining measurement precision in critical bands.
Solution Approach 2:
The patent applies different quality levels of feedback tone configuration to different frequency bands based on local requirements. Specifically, it configures comprehensive tone indices for bands requiring high precision channel state information while using reduced tone sets for other bands, achieving local optimization of measurement precision versus overhead trade-offs.
2Productivity
If increased number of spatial streams are used, then communication capacity is improved, but device complexity increases
Solution Approach 1:
The patent changes the parameter of tone index configuration to adapt to different spatial stream requirements. By defining specific tone index patterns (e.g., [-122, -116, -108:32:−12, -4, 2, 4, 12:32:108, 116, 122] for 20 MHz bands), it enables efficient feedback for multiple spatial streams without requiring proportional increases in feedback overhead, thus managing device complexity while maintaining communication capacity.
3Productivity
If bandwidth is increased in EHT standard, then communication efficiency is improved, but feedback overhead increases
Solution Approach 1:
The patent segments the wide bandwidth into multiple 20 MHz, 40 MHz, or 80 MHz bands and configures feedback tones selectively for each segment. This allows the system to support increased total bandwidth for improved communication efficiency while controlling feedback overhead by not configuring full feedback tones across the entire wide band simultaneously, but rather in a segmented manner based on specific band requirements.
Data Source
AI summary
Proposed are a method and device for receiving a feedback frame in a wireless LAN system. Specifically, a beamformer receives a feedback frame for MIMO beamforming from a beamformee and decodes the feedback frame. The feedback frame includes a first feedback tone for a preset frequency band. When the preset frequency band is the 20 MHz band, the tone index of the first feedback tone is set to [−122, −116:8:−4, −2, 2, 4:8:116, 122] when Ng is 8, and [−122, −116, −108:32:−12, −4, −2, 2, 4, 12:32:108, 116, 122] when Ng is 32. When the preset frequency band is the 40 MHz band, the tone index of the first feedback tone is set to [−244:8:−4, 4:8:244] when Ng is 8, and [−244, −236:32:−12, −4, 4, 12:32:236, 244] when Ng is 32.