You do that in hardware. Do the Mac, phy and RF in hardware. This is what the qca hardware does. a On Mar 13, 2016 5:25 PM, "David Lang" wrote: > On Sat, 12 Mar 2016, Adrian Chadd wrote: > > On 12 March 2016 at 11:14, Henning Rogge wrote: >> >>> On Sat, Mar 12, 2016 at 3:32 PM, Wayne Workman >>> wrote: >>> >>>> I understand that Broadcom was paid to develop the Pi, a totally free >>>> board. >>>> >>>> And they already make wireless chipsets. >>>> >>> >>> The question is how easy would it be to build a modern 802.11ac >>> halfmac chip... the amount of work these chips do (especially with 3*3 >>> or 4*4 MIMO) is not trivial. >>> >> >> It's not that scary - most of the latency sensitive things are: >> >> * channel change - eg background scans >> * calibration related things - but most slow calibration could be done >> via firmware commands, like the intel chips do! >> * transmit a-mpdu / retransmit >> * transmit rate control adaptation >> * receiving / block-ack things - which is mostly done in hardware anyway >> * likely some power save transition-y things too >> > > you are ignoring MU-MIMO, the ability to transmit different signals from > each antenna so that the interference patterns from the different signals > result in different readable data depending on where the receiver is in > relation to the access point is not a trivial thing. > > But it's one of the most valuable features in the spec. > > David Lang >