I’m considering using the USRP together with the 802.11 stack to
some 802.11 MAC layer changes. I’m sending from an 11b card at the base
to my USRP/RFX2400.
One shortcoming at present is that the code doesn’t generate ACKs for
received frames. There are quite strict timing requirements for ACK
generation: for 11b at the base rate the ACK should be sent within a
measured in microseconds. I can increase the ACKTimeout but apparently
there’s a hard limit in my 802.11 equipment at 746us beyond which I will
incur a rentransmission.
I’m prepared to wade into the code but its a fool’s errand if the
will be too high to ACK within a few hundred microseconds. I’m worried
the block latencies and USB round-trip delay would seem to make this
impossible. If anyone here can give me an informed opinion then I’ll be
really happy. So, does anyone know if it is it possible to generate an
within 700us or so of receiving a data frame?