CVSROOT: /cvs
Module name: src
Changes by: s...@cvs.openbsd.org 2021/03/12 09:26:27
Modified files:
sys/conf : files
Added files:
sys/net80211 : ieee80211_ra.c ieee80211_ra.h
Log message:
Add RA, a new 11n Tx rate adaptation module for net80211.
Written by Christian Ehrhardt and myself, based on ieee80211_mira.c
but with significant changes.
The main difference is that RA does not attempt to precisely measure
actual throughput but simply deducts a loss percentage from the
theoretical throughput which can be achieved by a given MCS.
Unlike MiRa, RA does not use timeouts to trigger probing.
Probing is triggered only by changes in measured throughput.
Unlike MiRA, RA doesn't care whether a frame was part of an A-MPDU.
RA simply collects statistics for individual subframes. This makes reporting
very easy for drivers and seems to work well enough in practice.
Another difference is that drivers can report multi-rate retries properly
via ieee80211_ra_add_stats_ht(mcs, total, fail) which can be called
several times before ieee80211_ra_choose() selects a new Tx rate.
There is no reason any issues could not be fixed in ieee8011_mira.c but
I felt it was a good moment to burn the house down and start over.
And since this code diverges from how MiRA is described in the research
paper applying the "MiRA" label becomes inappropriate.
