From mboxrd@z Thu Jan 1 00:00:00 1970 From: Felix Fietkau Date: Thu, 28 Mar 2013 20:00:40 +0100 Subject: [ath9k-devel] Fixing the rate and rate relationship to OFDM In-Reply-To: <800E57B7-01E9-4239-AD8E-FE3E1058650E@aim.com> References: <800E57B7-01E9-4239-AD8E-FE3E1058650E@aim.com> Message-ID: <51549358.90603@openwrt.org> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: ath9k-devel@lists.ath9k.org On 2013-03-27 7:49 PM, John Clark wrote: > Many people seem to desire the bit rate to be the 'highest possible', > and have that automagically set. What's wrong with the current behavior of picking the rate that causes the least wasted airtime? > For some applications, I like to be able to set a specific bit rate, > and have that bit rate used no matter the resulting errors. That can be quite problematic with 802.11n aggregation. Any frame transmission that has failed after too many retries causes a BlockAck Request to be sent, which can cause other (potentially unrelated) frames to be dropped on the receiver side. Why do you want to do this at all? > I have looked a the code briefly, and it seems that there is the > possibility for setting up several retries, with changes in bit > rate. > > So, the questions are: > > 1) how to 'fix' a rate, disable adjustments on retries, etc? To do this per application, you'd have to put some ugly hacks into various layers. > 2) What is the relationship between the bit rate selected at this OS level, > and the subcarrier modulation of the RF signal? The standard describes what modulations are used for specific bitrates. - Felix