[Madwifi-devel] backoff time calculation sample, mistrel (rate adaptation algorithms)? From: Neda Koci - 2008-06-19 12:48:04 Attachments: Message as HTML ```Hi everyone, I'm trying to add the rate adaptation algorithms as implemented in madwifi to a simulator and I just noticed that the backoff window calculation in sample and minstral too is done taking into a account cwmin=3 and cwmax=10 so basicaly if you calculate transmission time tt the backoff taken into account will be the following for (x = 0; x <= short_retries + long_retries; x++) { cw = MIN(WIFI_CW_MAX, (cw + 1) * 2); tt += (t_slot * cw / 2); } for a given number of retries (802.11a/g t_slot=9usec ) you'll have a backoff set to 36usec for the first retry and set to 45usec for all other retries ??!!!!!!!!!!!!! If someone has already encountered this can you please tell me if there is smoething escaping to my understanding.. Is the same calucation also true for mac implementation !!! Thank you very much Neda Kind Regards Ms. Neda Koci EuMI - NetCentric Univ. of Trento 06-07 & Univ. of Edinburgh 07-08 Italy ```
 [Madwifi-devel] backoff time calculation sample, mistrel (rate adaptation algorithms)? From: Neda Koci - 2008-06-19 12:48:04 Attachments: Message as HTML ```Hi everyone, I'm trying to add the rate adaptation algorithms as implemented in madwifi to a simulator and I just noticed that the backoff window calculation in sample and minstral too is done taking into a account cwmin=3 and cwmax=10 so basicaly if you calculate transmission time tt the backoff taken into account will be the following for (x = 0; x <= short_retries + long_retries; x++) { cw = MIN(WIFI_CW_MAX, (cw + 1) * 2); tt += (t_slot * cw / 2); } for a given number of retries (802.11a/g t_slot=9usec ) you'll have a backoff set to 36usec for the first retry and set to 45usec for all other retries ??!!!!!!!!!!!!! If someone has already encountered this can you please tell me if there is smoething escaping to my understanding.. Is the same calucation also true for mac implementation !!! Thank you very much Neda Kind Regards Ms. Neda Koci EuMI - NetCentric Univ. of Trento 06-07 & Univ. of Edinburgh 07-08 Italy ```