[Ns-developers] SIFS is not handled in yans-wifi-phy

[kirillano]

Hi all!

  Running different wifi-scanarios with hidden stations in NS-3, I have observed a strange thing: inside SIFS interval PHY starts to receive packet and tells about about it to DcfManager. A bit later PHY starts to send ACK (which was sheduled by MacLow) and cancells EndSync method of YansWifiPhy without notifying DcfManager about this (and DcfManager does not reset m_rxing flag). So, DcfManager thinks that the medium is busy (IsBusy () says true), but actually that is not right.
  Also chapter 9.2.10 DCF timing relations says, that inside SIFS we can not know the state of the medium (that is a time to switch from TX to RX), and can not start to receive any packet. But YansWifiPhy goes to IDLE (or CCA_BUSY) state and can start receiving a packet inside SIFS (see picture in attachment)

Regards, Kirill V. Andreev
IITP RAS
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