Pilot Tone Configuration for CFO Tracking in Wide Bandwidth WLAN
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Solution Overview
Problem
Existing wireless LAN systems face challenges in efficiently utilizing increased spatial streams and bandwidths, particularly in the 6 GHz band, which affects overall throughput and latency.
Innovation Solution
The proposed method involves configuring a tone plan and pilot tones for wide bandwidths, specifically for 480 MHz and 640 MHz channels in the 6 GHz band, to improve Carrier Frequency Offset (CFO) tracking and compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If wide bandwidth (480 MHz/640 MHz) is used in 6 GHz band, then throughput is improved, but Carrier Frequency Offset tracking and compensation becomes difficult
Solution Approach 1:
The wide bandwidth channel is divided into multiple sub-channels, each with its own pilot tones. This segmentation allows CFO tracking to be performed independently in each sub-channel, making the tracking process manageable despite the overall wide bandwidth. The patent divides the 480 MHz or 640 MHz channel into smaller frequency segments with dedicated pilot tones for each segment.
Solution Approach 2:
Pilot tones are introduced as intermediary reference signals inserted at specific positions within the tone plan. These pilot tones serve as mediators that enable the receiver to estimate and compensate for CFO by comparing the received pilot tones with the expected pilot tones at known positions in the frequency domain.
2Productivity
If increased number of spatial streams is used, then data rate is improved, but signaling complexity increases
Solution Approach 1:
The tone plan structure with pilot tones at specific positions serves multiple functions simultaneously: it enables CFO estimation, provides channel estimation references, and supports multiple spatial streams. This universal structure reduces the need for separate signaling mechanisms for different functions, thereby reducing overall signaling complexity while supporting increased spatial streams.
Data Source
AI summary
Proposed are a method and apparatus for receiving a PPDU on the basis of control information related to a pilot tone in a wireless LAN system. Particularly, a reception STA receives a PPDU from a transmission STA. The reception STA acquires control information related to a tone plan and pilot tone by decoding the PPDU. The reception STA decodes a data field of the PPDU on the basis of the control information. If a bandwidth of the PPDU is 480 MHz, the tone plan is a 6×996 tone RU or 3×2020 tone RU. An index of a first pilot tone within the 6×996 tone RU or 3×2020 tone RU is ±{112, 246, 360, 494, 598, 732, 846, 980, 1136, 1270, 1384, 1518, 1622, 1756, 1870, 2004, 2160, 2294, 2408, 2542, 2646, 2780, 2894, 3028}.