Thanks. I already checked the code (mac-timers_802_11e.cc, mac-802_11e.cc).
In BackoffTimer_802_11e::pause(), I can find the new EDCA rule as th following. line 552, rtime_[pri] -= slottime; line 582, if(EDCA)rtime_[pri] -= ((slots + 1) * slottime); // +1 slot for new EDCA rule But, I can't assure whether the transmission is initiated after additional one slot after the backoff counter has reached zero. I become mixed up.~~ Best regards. 2006/3/15, Sven Wiethoelter <[EMAIL PROTECTED]>: > > > On Mar 15, 2006, at 1:40 PM, Jongman Heo wrote: > > > > > According to section 9.9.1.3 in the IEEE 802.11e standard, > > > > one and only one of the following actions is allowed at slot > > boundaries: > > - decrement of backoff timer, or > > - initiate transmission, or > > - backoff procedure due to internal collision, or > > - do nothing. > > > > > > So, > > > > 1. > > Backoff counter is resumed one slot time before the AIFS expiration. > > > > 2. > > However, since a single MAC operation per slot is permitted > > (backoff decrement or packet transmission), > > > > when the backoff counter decrements to 0, the station cannot > > transmit immediately, but has to wait for a further backoff > > slot if the medium is idle, or a further AIFS expiration if > > the medium is busy. > Hi, > > exactly this has been included in the new EDCA model for ns-2.28. The > updated backoff code can be found in mac-timers_802_11e.cc/h. > > Best regards, > Sven > > > > > > I think that 802.11e TKN code is a good implementation of IEEE > > 802.11e. > > > > However, it seems that the implementation conforms to the requirement > > 1, but do not to the requirement 2. > > > > Am I correct? > > > > > > ps. > > The following paper can be a good guide. > > > > Giuseppe Bianchi, "Understanding 802.11e Contention-Based > > Prioritization Mechanisms and Their Coexistence with Legacy 802.11 > > Stations", IEEE Network, 2005 > > > > > > > > > -- ============================= Jongman Heo
