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[50.78.19.50]) by smtp.gmail.com with ESMTPSA id s4-20020ad45004000000b0063f88855ef2sm3638557qvo.101.2023.10.24.08.40.57 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 24 Oct 2023 08:40:58 -0700 (PDT) Message-ID: <71f5cd1f-ea9d-4e47-bc4b-eeb0a1ceb310@gmail.com> Date: Tue, 24 Oct 2023 08:40:56 -0700 Precedence: bulk X-Mailing-List: iwd@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: Is the data rate estimation for 5GHz channels overly pessimistic? Content-Language: en-US To: Denis Kenzior , Simonas Kazlauskas Cc: iwd@lists.linux.dev References: <5780e1b2-8956-46bb-8116-b513cc564cea@gmail.com> <5ff58310-c5ee-4694-821a-0c802cdedb89@gmail.com> <05aedfe6-82ad-4e41-a9fa-e9f8a5619947@gmail.com> <30b6dad4-64b2-41ca-8712-053cb1396eaf@gmail.com> <29094eca-dcf8-4234-8afc-13d37db8450c@gmail.com> <9e12bf94-aa83-4fe6-b045-8dab45b264ae@gmail.com> <3d2c3d76-e08c-4d71-8a72-7193dd51cbfc@gmail.com> <8a9039e3-1db3-459f-874b-e53d8dcdc16d@gmail.com> <1740def7-87b2-4d14-a6b1-c4522b9dcbf1@gmail.com> From: James Prestwood In-Reply-To: <1740def7-87b2-4d14-a6b1-c4522b9dcbf1@gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 10/24/23 8:32 AM, Denis Kenzior wrote: > Hi James, > >>> >>> They are not made up, they're direct from 802.11.  But again, they're >>> the _minimum_ specified sensitivity.  Hardware typically does better. >> >> The rates/MCS table (ht_vht_rates) is from 802.11, but the mapping >> from RSSI to MCS index's (ht_vht_he_base_rssi) is not. The spec just >> has a formula for calculating the rate using a given MCS/channel >> width. IWD just chooses what it thinks the MCS will be for a given RSSI. > > Sheesh!  Everything is directly from 802.11. > > 80211-2020.pdf, page 2835, Table 17-18. > 80211ax-2021.pdf, page 642, Table 27-51 Apparently wherever I got them from, got them from the spec. IIRC I couldn't find such tables when I was doing this, and found something online. Hence why I left this comment: * Note: The values here are not based on anything from 802.11 but data * found elsewhere online (presumably from testing, we hope). The two * indexes for HE (MCS 11/12) are not based on any data, but just * increased by 3dB compared to the previous value. We consider this good * enough for its purpose to estimate the date rate for network/BSS * preference. I suppose this can be removed now since they did in fact come from the spec. > >> >> I don't remember exactly where I got those values from but this seems >> to match: >> > > The spec? > > Regards, > -Denis