LPI Control Frame Duplication for 6 GHz Range Extension
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Solution Overview
Problem
Low Power Indoor (LPI) transmissions in the 6 GHz wireless band have a limited range due to strict power spectrum density requirements, and existing methods are not compatible with legacy devices, leading to reduced spectral efficiency and increased latency.
Innovation Solution
The method involves duplicating 20 MHz HE PPDUs over multiple sub-channels within an 80 MHz bandwidth to extend the transmission range while maintaining compatibility with legacy devices, using techniques like Maximum Ratio Combining (MRC) and 64-point cross-correlations for decoding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If LPI transmission power is reduced to meet power spectrum density requirements in the 6 GHz band, then interference with other wireless networks is reduced, but the transmission range and coverage area are significantly limited
Solution Approach 1:
The transmission bandwidth is segmented into multiple sub-channels (e.g., four 20 MHz sub-channels within 80 MHz bandwidth), with the control frame transmitted independently on each sub-channel. This segmentation allows the system to maintain low power density on each individual sub-channel while achieving extended coverage through spatial diversity across multiple frequency segments.
Solution Approach 2:
The invention transitions from single-channel transmission to multi-channel transmission by duplicating the control frame across multiple 20 MHz sub-channels. This dimensional expansion in the frequency domain enables the system to overcome the limited range of single low-power transmissions while maintaining compliance with power spectrum density requirements.
2Adaptability or versatility
If separate PPDUs are used for legacy device control frames, then legacy device compatibility is maintained, but spectral efficiency is reduced and latency increases
Solution Approach 1:
The invention merges legacy device support with high-throughput transmissions by embedding duplicated control frames within the same PPDU structure used for data transmission. The control frames are duplicated across multiple sub-channels within the same transmission opportunity, eliminating the need for separate beacon PPDUs and improving spectral efficiency while maintaining legacy compatibility.
Solution Approach 2:
The PPDU structure is designed to serve multiple functions simultaneously: it carries high-throughput data for modern devices while also containing duplicated control frames that legacy devices can decode from any of the multiple sub-channels. This multi-functional design eliminates the need for separate transmission streams for different device types.
3Device complexity
If control frames are transmitted over a single primary 20 MHz sub-channel, then transmission simplicity is maintained, but the range of reliable transmission is limited by LPI power constraints
Solution Approach 1:
The control frame transmission is segmented across multiple 20 MHz sub-channels, with each sub-channel carrying an independent copy of the control frame. This segmentation enables receivers at greater distances to reliably decode the control frame from any sub-channel where the signal strength is sufficient, thereby extending the reliable transmission range while maintaining relatively simple transmission implementation.
Data Source
AI summary
Embodiments of the present invention provide duplication schemes for control frames to extend the range of LPI in the 6 GHz wireless band for EHT WLAN. Duplicate 20 MHz legacy preambles containing L-STF, L-LTF, L-SIG and RL-SIG, U-SIG and EHT-SIG fields may be used to transmit beacon and other control frames using duplicate PPDUs to extend transmission range thereof. Non-HT duplication can be performed to maintain backwards compatibility with legacy devices. HE duplication can include duplication of a 20 MHz HE SU PPDUs over 40 MHz, 80 MHz, 160 MHz or 320 MHz portions, for example. DCM+MCS0 or duplication over DCM+MCS0 may be applied to the payload, and a duplication indication is inserted in the U-SIG field or EHT-SIG field to indicate if the duplication is applied to the payload over DCM+MCS0.