Hello,
ePMP does have the CINR requirement for an OFDM system that was described earlier in the email chain. It is of course more than FSK. This is assuming a solid noise floor. However, depending on the frequency of the interferer occupying the channel, ePMP can operate with lower CINR such as that approaching FSK. When the CINR is lower due to the interferer, the packet will not make it through, but the packet will be retried. ePMP has been architected to keep its MCS higher in this type of scenario with an intermittent interferer and hence should achieve higher throughput. Therefore, if you have an intermittent interferer raising your noise floor to a high value, ePMP should perform well. If the interferer is fairly regular / constant, then it would not be able to overcome this similar to any OFDM system. Dan Sullivan ePMP Software Manager From: Af [mailto:[email protected]] On Behalf Of Sean Heskett Sent: Wednesday, April 22, 2015 10:49 AM To: [email protected] Subject: Re: [AFMUG] Will ePMP work better in heavy interference 2.4ghz FSK only needs 3db above the noise floor to modulate at 1x. It needs 10db to modulate at 2x The 450 and epmp need at least 10db to hold a connection at the lowest modulations. To get the high modulations out of those products you need 25db or more. So if your noise floor is -60 for FSK you need a -57 for 1x or -50 for 2x For the other products you'll need -50 for the lowest modulations and a -35 or better for the highest modulations. As you can see FSK will always be the best platform in the face of interference. The others work but don't expect miracles because 25db SNR in a noisy environment just isn't realistic. YMMV Pick a band with clean spectrum (ie 5.4, 5.1, 3.65 etc) -sean On Wednesday, April 22, 2015, Matt <[email protected]<mailto:[email protected]>> wrote: > Not in our experience...we have not had great success migrating from FSK 100 > series to ePMP. Noise floor SNR sucks. Have you tried migrating from 2.4 FSK too 2.4 450 at a very noisy site? Have a site I need more capacity at and frequency options are limited. >> Hey guys, >> >> We're on a tower with a basically dead WISP that has 3 sectors of 2.4ghz up >> there. It's 10 year old equipment so not even sure what brand. Anyway, we >> placed 4 sectors of Ubiquiti 2.4 gear on 10 MHz channels with RF Armor on >> all sectors. We found that channels 1 and 11 were best so we did channel 1 >> on North and south sector and channel 11 on east and west so they're back to >> back. The back to back sectors are separated by a solid water tank/tower but >> they still see each other at -55 which is hotter than I thought they would >> be with Armor and the water tank. >> >> Anyway, we don't get the best of performance due to self interference as >> well as interference from the old WISP equipment. In your experience with >> ePMP, would we see a noticeable improvement going to ePMP 2.4 gear and >> syncing it all for channel reuse on the back to back sectors? Would this >> also give us the added benefit that we would reduce adjacent channel >> interference with ourselves because all sectors would transmit and receive >> with each other? >> >> Thank you
