Hi Seongho, that paper looks quite interesting. Are you planning to publish code/patches for your implementation as well? It would be nice to have dynamic A-MPDU limiting integrated in minstrel_ht. Thanks, - Felix On 26/10/2014 12:14 AM, Seongho Byeon wrote: > > Hi, I am Ph.d. student in Seoul National University , Korea. > Recently, we have dealt with the problem you observe, and we published > a paper into CoNEXT 2014 which is a major conference in our field. > > Title of the paper 'MoFa: Mobility-aware Frame Aggregation in WiFi > networks'. > You can download it a site below. > http://www.mwnl.snu.ac.kr/~schoi/publication/Conferences/14-CONEXT-BYEON.pdf > <http://www.mwnl.snu.ac.kr/%7Eschoi/publication/Conferences/14-CONEXT-BYEON.pdf> > If you have a question please contact me anytime. > > Best regards, > Seongho Byeon. > > Thank you for sharing the story. > Even if I consider interference as a possibility, still I can't > justify the higher > chance of frame loss in the second half of the aggregate frame. > > We use > > PCI-express 3 antenna dual band cards > product: AR93xx Wireless Network Adapter > and/or > Atheors AR5B97 which is a 2.4 GHz dual antenna internal card in a laptop > > we also tried TP-LINK TL-WDN4200 N900as the receiver. > > However we see the same results. > we mostly use MCS 20-23, sgi = 0, 20 MHz channels. > > The loss pattern is something like this > (each line is an imaginary aggregated frame and each bit is the fate > of the MPDU) > > 11111111111100011000000000000 > 11111110001101011010000000000 > 11111000000000000000000000000 > 11111111111010100000000000000 > 11111100101010000000000000000 > > The interesting part is that with the start of the next frame error > rate goes down initially > then it goes up again in the second portion of the packet. > > Best, > Ali > > > On 25/10/2014 2:30 PM, Adrian Chadd wrote: > > On 25 October 2014 08:28, Ali Abedi<a2abedi@xxxxxxxxxxxx> > <mailto:a2abedi@xxxxxxxxxxxx>wrote: > > Hi Adrian, We have a high end spectrum analyzer. So we are > sure there is no background interference We run our > experiments in the 5 GHZ spectrum. The channel conditions can > still vary due to the movement of the people in the vicinity > of the experiment setup. We select a rate that experiences at > least 20% error on average. Since if the error is 100% or 0% > it's not interesting for us. My point is if the channel > conditions change the distribution of failed packets should be > uniform. The first and second half of the packets have the > same chance to be received successfully. > > Here's a little story. My first wifi contract had me spend months > trying to figure out why an AP was losing its mind. It'd get stuck > in a "stuck beacon" loop and only a hard powercycle of /all/ of > the access points in an area would clear it. It turned out that > the PCB design had some non-grounded / non-populated tracks that > just "happened" to form a 2GHz resonator. Once we grounded those > tracks, the APs started behaving themselves. The company in > question spent months with high end spectrum analysis kit in the > lab (where it never happened) and underground (where it did > happen.) It's only after they stuck the spectrum analyser probe > _inside the access point_ right up close to the NIC did they see > it. Here's the spectrum analyser traces. You can see the > peak.http://www.creative.net.au/ath/So, weirder crap has happened. > Which NICs and which MCS rates are you using? -adrian > > _______________________________________________ > ath9k-devel mailing list > ath9k-devel@xxxxxxxxxxxxxxx <mailto:ath9k-devel@xxxxxxxxxxxxxxx> > https://lists.ath9k.org/mailman/listinfo/ath9k-devel > -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
