| From 888da5f48030e45ce14f43a2bf7be07ec79b60d4 Mon Sep 17 00:00:00 2001 |
| From: Dennis Bland <dennis@dbperformance.com> |
| Date: Wed, 20 Apr 2022 20:56:38 -0600 |
| Subject: [PATCH 2/5] Regulatory update for 6 GHz operation in United States |
| (US) |
| |
| With the 6 GHz band (U-NII-5, U-NII-6, U-NII-7, U-NII-8) in USA, the FCC |
| introduces the concept of a fixed PSD (Power Spectral Density) for all |
| supported 6 GHz channel widths for LPI (Low Power Indoor) environments. |
| Wider channel widths have a higher noise floor, therefore specifying a |
| fixed PSD allows wider channels to operate at a higher EIRP to maintain |
| the same S/N ratio as smaller channel widths. |
| |
| While the 6 GHz specification also allows a "Standard" power mode with |
| higher EIRP and PSD limits, these devices are also required to employ |
| AFC (Automatic Frequency Coordination) which normally requires GNSS. |
| Currently there is no way to specify different EIRP and PSD levels for |
| APC and non-APC devices. Therefore, only LPI mode is considered here. |
| |
| LPI requires non-client (AP) devices to have a maximum PSD of 5 dBm/MHz |
| and a maximum EIRP of 30 dBm. LPI requires client (STA) devices to have |
| a maximum PSD of -1 dBm/MHz. The maximum channel width is 320 MHz. |
| |
| The following equation is used to calculate the EIRP from the PSD and |
| channel width: |
| |
| EIRP = PSD + 10*log(channel width in MHz) |
| |
| Using the maximum PSD values of 5 and -1 for APs and STAs respectively, |
| the EIRP in dBm for a given channel width can be calculated: |
| |
| Channel Width (MHz) AP STA |
| ------------------------------------------------ |
| 20 18 12 |
| 40 21 15 |
| 80 24 18 |
| 160 27 21 |
| 320 31 (max 30) 25 (max 24) |
| |
| For channel widths up to 160 MHz, the maximum PSD is the limiting factor. |
| For the 320 MHz channel width, the maximum EIRP is the limiting factor. |
| |
| Unfortunately, because there is currently no mechanism to specify |
| different power levels for AP and STA modes, and for different channel |
| widths, the smallest value has to be selected, which is 12 dBm. This |
| will likely cause connectivity problems with larger channel widths until |
| these additional parameters can be added. |
| |
| 6 GHz operation on oil platforms, vehicles, boats, trains, and drones is |
| prohibited except on commercial aircraft above 10,000 feet altitude. |
| An IR (Initiate Radiation) restriction is mentioned in the 6 GHz |
| specification. |
| |
| Signed-off-by: Dennis Bland <dennis@dbperformance.com> |
| Signed-off-by: Seth Forshee <sforshee@kernel.org> |
| --- |
| db.txt | 3 +++ |
| 1 file changed, 3 insertions(+) |
| |
| diff --git a/db.txt b/db.txt |
| index 062ad8a..fcdc74a 100644 |
| --- a/db.txt |
| +++ b/db.txt |
| @@ -1649,6 +1649,9 @@ country US: DFS-FCC |
| # https://www.federalregister.gov/documents/2021/05/03/2021-08802/use-of-the-5850-5925-ghz-band |
| # max. 33 dBm AP @ 20MHz, 36 dBm AP @ 40Mhz+, 6 dB less for clients |
| (5850 - 5895 @ 40), (27), NO-OUTDOOR, AUTO-BW, NO-IR |
| + # 6g band |
| + # https://www.federalregister.gov/documents/2020/05/26/2020-11236/unlicensed-use-of-the-6ghz-band |
| + (5925 - 7125 @ 320), (12), NO-OUTDOOR, NO-IR |
| # 60g band |
| # reference: section IV-D https://docs.fcc.gov/public/attachments/FCC-16-89A1.pdf |
| # channels 1-6 EIRP=40dBm(43dBm peak) |
| -- |
| 2.29.2 |
| |