On Fri, Mar 24, 2023 at 06:30:32PM -0500, Keshav wrote: > Hello Seth, > > Thank you for your reply. Please find below my comments. > > On Tue, Mar 21, 2023 at 11:38 AM Seth Forshee <sforshee@xxxxxxxxxx> wrote: > > > > On Sat, Mar 04, 2023 at 05:13:44PM -0600, Keshav wrote: > > > Hello, > > > > > > I noticed that wireless-regdb db.txt [1] has restricted India's 2.4 > > > GHz maximum power to only 20 dBm: > > > > > > country IN: > > > (2402 - 2482 @ 40), (20) > > > > > > However the Official Gazette of Government of India (PDF [3] linked in > > > URL [2]) mentions that upto 30 dBm is allowed in the 2.4 GHz band. > > > > > > 2.4 GHz Rules for India (IN): Pages 87 to 88 of PDF [3] > > > > > > I would like to mention that I am not an expert in this topic. I am > > > not sure if there's any other reason to restrict 2.4 GHz for India to > > > 20 dBm in the db.txt. I also couldn't find any other official > > > Government of India document that restricts the maximum power to 20 > > > dBm (due to some other reason). Please look into this and correct the > > > regulatory rules for India if needed. Thank you. > > > > > > Although not the topic of this email, you can also find the 5 GHz > > > Rules for India in the same PDF [3] (pages 94 to 97) if interested. > > > > > > [1] https://git.kernel.org/pub/scm/linux/kernel/git/sforshee/wireless-regdb.git/tree/db.txt?id=7f7a9f7bc6011b072b5427eced1ff19261764e95#n853 > > > > > > [2] https://dot.gov.in/spectrummanagement/gazette-notifications-delicensed-band > > > > > > [3] https://dot.gov.in/sites/default/files/Gazette_Notifications.pdf > > > > Sorry for the slow response. I've been attempting to research this as > > time allows, but I haven't had a lot of time for it, and the information > > is not well organized. > > > > [1] was the most complete summary I found for spectrum use in India. In > > particular Annex 1 has a table of GSR numbers relevant for unlicensed > > spectrum, which for 2.4 GHz is GSR No. 45(E) [2] and for 5 GHz is GSR > > No. 1048(E) [3]. It looks like the document you linked to just bundles > > these and other GSRs together, so as far as I can tell the information > > you provided looks accurate. > > > > The database stores maximum EIRP, not transmitter output power, so I > > think that 36 dBm is the correct value for 2.4 GHz (GSR No. 45(E) shows > > an ERP of 36dBm, but based on the maximum transmitter power of 30 dBm I > > think this is probably meant to be the EIRP). > > > > The 5 GHz rules look mostly right, except that it looks like 5250-5350 > > and 5470-5725 MHz both require DFS. They also require TPC, which Linux > > doesn't support, but the PSD limit restricts our max EIRP to below the > > threshold where TPC is required. > > > > So I think these are the correct rules for India: > > > > country IN: > > (2400 - 2482 @ 40), (36) > > (5150 - 5250 @ 80), (30) > > (5250 - 5350 @ 80), (24), DFS > > (5470 - 5725 @ 160), (24), DFS > > (5725 - 5875 @ 80), (30) > > > > If this looks right to you, I can send the patch to update the rules. > > > > Thanks, > > Seth > > > > [1] https://dot.gov.in/sites/default/files/NFAP%202018.pdf > > [2] https://dot.gov.in/spectrummanagement/delicensing-24-24835-ghz-band-gsr-45-e-5150-5350-ghz-gsr-46-e-and-5725-5875-ghz > > [3] https://dot.gov.in/spectrummanagement/license-exemption-5-ghz-gsr-1048e-dated-22102018 > > Based on your explanation, the numbers look right to me. However, I am > not an RF expert and I do not have enough knowledge to interpret these > rules correctly myself. Therefore I will defer to your judgement here. I am not an RF expert either. > There's one thing I forgot to mention in my previous email. I noticed > this discrepancy in db.txt because I came across the embedded regdb > rules defined in an ath11k wifi router running OpenWrt > (https://openwrt.org/toh/hwdata/dynalink/dynalink_dl-wrx36), and > noticed that they are different from wireless-regdb db.txt rules. The > "iw" outputs from the ath11k device are pasted below for your > reference. > > # iw reg get > global > country IN: DFS-UNSET > (2402 - 2482 @ 40), (N/A, 20), (N/A) > (5150 - 5250 @ 80), (N/A, 30), (N/A) > (5250 - 5350 @ 80), (N/A, 24), (N/A) > (5470 - 5725 @ 160), (N/A, 24), (N/A) > (5725 - 5875 @ 80), (N/A, 30), (N/A) > > phy#1 (self-managed) > country IN: DFS-FCC > (2402 - 2472 @ 40), (N/A, 30), (N/A) > (5170 - 5250 @ 80), (N/A, 30), (N/A), AUTO-BW > (5250 - 5330 @ 80), (N/A, 24), (0 ms), DFS, AUTO-BW > (5490 - 5730 @ 160), (N/A, 24), (0 ms), DFS, AUTO-BW > (5735 - 5835 @ 80), (N/A, 30), (N/A), AUTO-BW > > phy#0 (self-managed) > country IN: DFS-FCC > (2402 - 2472 @ 40), (N/A, 30), (N/A) > (5170 - 5250 @ 80), (N/A, 30), (N/A), AUTO-BW > (5250 - 5330 @ 80), (N/A, 24), (0 ms), DFS, AUTO-BW > (5490 - 5730 @ 160), (N/A, 24), (0 ms), DFS, AUTO-BW > (5735 - 5835 @ 80), (N/A, 30), (N/A), AUTO-BW > > # iw list > Wiphy phy1 > Frequencies: > * 2412 MHz [1] (30.0 dBm) > * 2417 MHz [2] (30.0 dBm) > * 2422 MHz [3] (30.0 dBm) > * 2427 MHz [4] (30.0 dBm) > * 2432 MHz [5] (30.0 dBm) > * 2437 MHz [6] (30.0 dBm) > * 2442 MHz [7] (30.0 dBm) > * 2447 MHz [8] (30.0 dBm) > * 2452 MHz [9] (30.0 dBm) > * 2457 MHz [10] (30.0 dBm) > * 2462 MHz [11] (30.0 dBm) > * 2467 MHz [12] (disabled) > * 2472 MHz [13] (disabled) > * 2484 MHz [14] (disabled) > > Wiphy phy0 > Frequencies: > * 5180 MHz [36] (30.0 dBm) > * 5200 MHz [40] (30.0 dBm) > * 5220 MHz [44] (30.0 dBm) > * 5240 MHz [48] (30.0 dBm) > * 5260 MHz [52] (24.0 dBm) (radar detection) > * 5280 MHz [56] (24.0 dBm) (radar detection) > * 5300 MHz [60] (24.0 dBm) (radar detection) > * 5320 MHz [64] (24.0 dBm) (radar detection) > * 5500 MHz [100] (24.0 dBm) (radar detection) > * 5520 MHz [104] (24.0 dBm) (radar detection) > * 5540 MHz [108] (24.0 dBm) (radar detection) > * 5560 MHz [112] (24.0 dBm) (radar detection) > * 5580 MHz [116] (24.0 dBm) (radar detection) > * 5600 MHz [120] (24.0 dBm) (radar detection) > * 5620 MHz [124] (24.0 dBm) (radar detection) > * 5640 MHz [128] (24.0 dBm) (radar detection) > * 5660 MHz [132] (24.0 dBm) (radar detection) > * 5680 MHz [136] (24.0 dBm) (radar detection) > * 5700 MHz [140] (24.0 dBm) (radar detection) > * 5720 MHz [144] (24.0 dBm) (radar detection) > * 5745 MHz [149] (30.0 dBm) > * 5765 MHz [153] (30.0 dBm) > * 5785 MHz [157] (30.0 dBm) > * 5805 MHz [161] (30.0 dBm) > * 5825 MHz [165] (30.0 dBm) > * 5845 MHz [169] (disabled) > * 5865 MHz [173] (disabled) > > Looks like ath11k restricts the maximum EIRP to 30 dBm for 2.4 GHz. > Again I am not an expert so I can't comment on whether 30 dBm vs 36 > dBm is the correct maximum EIRP value for 2.4 GHz. I find the rules in GSR No. 45(E) unclear and a little confusing. Broadly you can think of EIRP(dBm) = tx_output_power(dBm) + antenna_gain(dBi). If you look at the US rules [1] you can see that it specifies EIRP assuming an antenna gain of 6 dBi or less, with adjusments for antennas with larger gains. GSR No. 45(E) does not define things as clearly, but when I see a transmitter output power of 30 dBm and a maximum effective radiated power of 36 dBm it leads me to think that it has a similar model of assuming an antenna gain <= 6 dBi. I could be wrong, but from what I see this interpretation makes the most sense to me. 30 dBm is certainly a safe value though, as the max EIRP should be at least that much under any interpretation. [1] https://www.ecfr.gov/current/title-47/chapter-I/subchapter-A/part-15/subpart-C/subject-group-ECFR2f2e5828339709e/section-15.247 Thanks, Seth _______________________________________________ wireless-regdb mailing list wireless-regdb@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/wireless-regdb
