Let's break this down a bit. Firstly, what outdoor PTMP platform is really using WiFi anymore? *shakes head*
Mu-MIMO only works if the clients are sufficiently spread apart (physically), and their tx/rx windows can fit into almost the same timeframe. Any degradation in signal of one client that ends up in the same window as other clients reduces the overall capacity of the AP (like in many other situations). It can, in some situations, lead to cumulative transfer windows where overall throughput ends up getting reduced as the rx/tx hold time for the other clients end up taking a hit in efficiency. This is one of the few failings of MU-MIMO, not even taking into account "massive" systems like 14x14 that end up costing quite a bit in overall power budget due to the number of elements, further meaning that your range is severely limited in a system like this... so only decent in very dense situations. That's a unique niche. So, 80 clients. That's a pretty average number for a modern system (450, Mimosa, AC Prism Gen2). 30Mbps per client... okay, but most customers are actually streaming. Let's throw another margin on top of that and say a few Mbps for gaming. 10Mbps is a nice round number. Now, that data gets sent in most services in bursts and buffered, so it's not continuous. Let's take that average number down to about 8 Mbps. Now let's assume that maybe 70% of those 80 customers is doing something like that, and that's probably a generous number. 56 customers. So 56 customers x 8Mbps = 448Mbps. On a 20Mhz channel? Wait, this doesn't seem to work out! Soo.... 1024 QAM on a 20MHz channel gives you 250Mbps, very roughly. If you're optimistic about modern patterns, you're between an 80/20 and a 60/40 Download/Upload ratio on a split GPS synced system. 80/20 = 200Mbps Down, 50Mbps Up 60/40 = 150 Down, 100Mbps Up Let's say for the sake of argument that you're in the 80/20 camp, giving you 200Mbps to work with in above perfect conditions, gives you 3.57 Mbps per subscriber. Roughly 4M/sub, good for 480p streaming. That's a very expensive platform for that kind of throughput and subscriber count with such limitations in range and needed a "perfect storm" of client distribution and data patterns to really take advantage of. With working GPS in all modern platforms, I would be hard pressed to not use an additional 20mhz channel if available, or just cut the channel width in half to 10MHz each, and put up 4 Mimosas or 4 Gen2 Prism radios and have far more than 4x the possible subscriber account, improved tx/rx efficiency, improved range (increasing distance and SNR in many situations), and greatly reduced cost. Again, I'm far more excited about the 4x increase in spectral efficiency via OFDMA that doesn't cause you to cut down on tx/rx chains for multi-client transmission (costing your range, per client snr, and per-client throughput in the process). MU-MIMO is and will always be a niche hack that never lived up to what was promised. On Tue, Feb 13, 2018 at 12:12 AM, Sean Heskett <af...@zirkel.us> wrote: > Being able to load a 450m AP with 80 subs and deliver 30mbps service to all > of them at peak Netflix time in a 20mhz channel without breaking a sweat is > worth every penny. > > But it’s one tool in the tool box and isn’t the best solution for every > deployment. > > 2 cents > > -sean > > > > On Mon, Feb 12, 2018 at 10:32 PM Josh Reynolds <j...@kyneticwifi.com> wrote: >> >> The more I dig into MU-MIMO, the more I realize it's not all that great. >> >> I am far more excited by the 9 client simultaneous transmissions in >> 802.11ax via OFDMA. >> >> On Mon, Feb 12, 2018 at 8:00 PM, Adam Moffett <dmmoff...@gmail.com> wrote: >> > 450 still does a few things that ePMP doesn't. >> > Plus there's that 14 chain MU-MIMO thing......ePMP will probably never >> > have >> > something like that. >> > UI is still sluggish on ePMP. >> > >> > On the other hand ePMP has gotten so many feature improvements over >> > these >> > past few years that it's gotten really hard to argue with the value it >> > provides. >> > >> > >> > ------ Original Message ------ >> > From: "Chuck McCown" <ch...@wbmfg.com> >> > To: af@afmug.com >> > Sent: 2/12/2018 8:27:56 PM >> > Subject: Re: [AFMUG] mini wisp >> > >> > The UI server was probably the worst I have ever seen. >> > >> > So, less than 25 subs per site, what speed packages do you sell to those >> > 25? >> > >> > Packetflux GPS sync. >> > >> > From: Joe Novak >> > Sent: Monday, February 12, 2018 5:20 PM >> > To: af@afmug.com >> > Subject: Re: [AFMUG] mini wisp >> > >> > What didn't you like about it? The interface came a long way since the >> > early >> > days of EPMP. We've got quite a bit deployed. A lot of people are having >> > weird GPS situations come up with the on-board GPS, we have this problem >> > once in a while too. Our packetflux sites are rock solid though. That is >> > assuming density isn't more then 25 per AP, because then I don't exactly >> > have enough experience with it. Most of our APs are sitting right around >> > 25 >> > customers, and according to airtime we still have quite a bit of room. >> > >> > On Mon, Feb 12, 2018 at 6:09 PM, Jaime Solorza >> > <losguyswirel...@gmail.com> >> > wrote: >> >> >> >> I separated frequencies to three I found cleanest on AFx5s...On Rockets >> >> and Powerbeams I choose one frequency and shut off the rest on APs and >> >> on >> >> PowerBeams I only use two...this method has worked well since August of >> >> 2017 >> >> when I replaced all the radios on this network and have had to change >> >> them >> >> since. Two of the WISPs live in Fabens and work with us on issues. >> >> The >> >> other one from El Paso uses my services once in a while and works with >> >> us as >> >> well. Texas Gas put up allot of 5GHz units around Fabens but still no >> >> issues. I used larger dishes at Wells and lift stations as well. >> >> >> >> Jaime Solorza >> >> >> >> On Feb 12, 2018 4:50 PM, "Jaime Solorza" <losguyswirel...@gmail.com> >> >> wrote: >> >>> >> >>> Two AF5x on same tower, One AP on second tower 20 ft away...all other >> >>> radios within 4 mile radius... >> >>> >> >>> Jaime Solorza >> >>> >> >>> On Feb 12, 2018 4:43 PM, "Chuck McCown" <ch...@wbmfg.com> wrote: >> >>>> >> >>>> All on the same tower, right? >> >>>> >> >>>> From: Jaime Solorza >> >>>> Sent: Monday, February 12, 2018 4:41 PM >> >>>> To: Animal Farm >> >>>> Subject: Re: [AFMUG] mini wisp >> >>>> >> >>>> Yes..I have two AF5X links as PTP and 25 radios all in 5 GHz off 4 >> >>>> APs >> >>>> in Fabens, Texas sharing spectrum with 3 WISPs...no issues... >> >>>> >> >>>> Jaime Solorza >> >>>> >> >>>> On Feb 12, 2018 4:32 PM, "Chuck McCown" <ch...@wbmfg.com> wrote: >> >>>>> >> >>>>> Talking to a friend that wants to build a small wisp. He is about >> >>>>> 5.5 >> >>>>> miles from a backbone connection. I would suggest AF5X to him but >> >>>>> he is >> >>>>> gonna want to use 5 GHz for his wisp I presume. >> >>>>> >> >>>>> Can an AF5X and some 5 GHz cambium (or others) access points >> >>>>> peacefully >> >>>>> coexist on a tower? >> >>>>> Very rural area. Not expecting much interference other than home >> >>>>> routers. >> > >> >
