Thank you Dan I have tried to work with support but my schedule and Vijay's are not very compatible. I spend most every day hanging on towers and driving so being in front of my computer to work on this stuff is only good for me late at night. I have KP sectors 90 degree with a 28dbi F/B radio. I've always been happy with KP stuff and since I dont have any SM's connected to the afflicted AP's on the opposite (Back facing) sector that uses the same channel I dont think this is the problem. My noise floor is somewhat higher than I would like and going to a 10mhz channel on the two AP's that have customers seems to have helped. I think I will go back to ACS in 10mhz and see how it performs. My problem with ACS is that the AP's auto choose close to the same channel around the entire cluster. We are considering adding a 5ghz omni on each tower to make use of where 2.4 just seems to have too much noise but I would like to save that spectrum for BH links where possible. I will follow up with you and let you know results.
Thanks Craig ----- Original Message ----- From: "Dan Sullivan" <[email protected]> To: [email protected] Sent: Tuesday, June 9, 2015 9:06:53 PM Subject: Re: [AFMUG] EPMP 10 mhz vs 20mhz Hi Craig, What you describe sounds like an UL interference problem to me, although you did indicate that you ran eDetect and did not see any interferers. Here is what I would try. If you are still setting up your sectors and the channel plan is still flexible, I would run ACS on each sector to find out the best channel(s) for each sector on a tower. ACS provides a measurement of every kind of noise / interferer seen (e.g. 802.11 based, Canopy, etc.). Once this is done, I would then select pick an ABAB configuration which optimizes the findings from ACS where the A and B channels are spaced at least 5 MHz apart. For example, using 2412 and 2437 provides 5 MHz guard band (i.e. 2422-2427). 5 MHz of guard band is all that is required when you run in TDD Sync. eDetect can now be run on each sector in order to detect 802.11 UL interferers. It will not detect other types of interferers. I would run eDetect in local mode as all spare time is spent looking for interferers. These steps should allow you to pick the best two channels for an ABAB configuration to solve your UL performance issues if it is due to interference. With regard to UL RSSI, when using the Subscriber Module Target Receive Level (TRL) on the AP in TDD Sync mode, this should be set around -60 dBm on the AP. This field defines the RSSI that the AP will hear from each SM. Each SM will change its transmit power so that the exact UL RSSI value as defined by the SM TRL is realized for the SM at the AP. If you set the value higher than this, then the back side sector AP will start hearing the SMs from this AP. This is because the front to back ratio of the sector antenna is 30-35 dB. If the SM TRL is -60 dBm, then the noise floor due to the backside sector is somewhere between -95 to -90 dBm. If the SM TRL is raised to -50 dBm, then the noise floor due to the backside sector is raised to between -85 to -80 dBm. The overall CINR is no different in either case and additional energy is added to the environment. ePMP has optimized its sector antennas with front to back ratio. I recommend using these sector antennas. If you use different sector antennas, choosing high gain antennas that have poorer front to back will actually hurt you. Say you choose a sector antenna that gives say 2 dB better gain, but the front to back suffers by 5-8 dB on average. Then the CINR will be decreased to 22-30 dB best case and the highest MCS may not be achieved on both the UL and the DL due to interference from your back sector. In the US and everywhere except for ETSI, the ePMP does not support CCA in TDD mode. It does not wait to transmit based on environmental noise. Therefore, if throughput and MCS is decreased at high RSSI for a site, this is most likely due to interferers occurring at the same time and raising the noise floor. With regard to 10, 20, or 40 MHz channels, what I would do is look at the noise level using ACS for each channel size. If you have really clean spectrum, you could use 40 MHz, but if not you might find cleaner 20 or 10 MHz channels that favor their use. In general the channel bandwidths perform comparably in similar noise environments (of course doubling the channel bandwidth doubles the noise floor). I hope this helps. Dan Sullivan ePMP Software Manager Cambium Networks Cambium Networks Community Forum From: Af [mailto:[email protected]] On Behalf Of Josh Reynolds Sent: Monday, June 08, 2015 3:41 PM To: [email protected] Subject: Re: [AFMUG] EPMP 10 mhz vs 20mhz None of our radios have high PPS load. Matter of fact, average packet size on our network is 1.3k. PPS per radio is very low. FWIW, there are no file sharers on our network. If they exist, their connection is encapsulated over VPN. Josh Reynolds CIO, SPITwSPOTS www.spitwspots.com On 06/08/2015 11:16 AM, Rory Conaway wrote: The pps and cpu load absolutely is another variable you need to take into acount, especially with 400 and 526mhz atheros �processors that are also running polling. � Ignore it as part of your overall strategy and you could be wasting spectrum. �If your ap never exceeds 80mbps, why do you want 30mhz channels. �Sarcasm aside, does that help you understand my point. Sent from fromm phone where I type with a single digit so please excuse shortcuts or typos. Rory Conaway Triad Wireless -------- Original message -------- From: Josh Reynolds <[email protected]> Date: 06/08/2015 2:17 PM (GMT-05:00) To: [email protected] Subject: Re: [AFMUG] EPMP 10 mhz vs 20mhz I think we are having two different conversations, and I have no idea what you are talking about right now. What we were discussing has to do with channel sizes, epmp, and ubiquiti. In particular, why UBNT 40mhz isn't any better than 30mhz in terms of efficiency. This part of the discussion has nothing at all to do with any theories on PPS you may have, other than those you have tried to inject into this discussion. On Jun 8, 2015 10:07 AM, Rory Conaway <[email protected]> wrote: Excopt that as was mentioned before, the s/n ratio goes down and if you aren't hitting the limits of the physical layer in 20MHz, why do it? Sent from fromm phone where I type with a single digit so please excuse shortcuts or typos. Rory Conaway Triad Wireless -------- Original message -------- From: Josh Reynolds <[email protected]> Date: 06/08/2015 12:43 PM (GMT-05:00) To: [email protected] Subject: Re: [AFMUG] EPMP 10 mhz vs 20mhz I can assure you that on radios connected in a ptp config or small ptmp, that you will see more throughput on the 30mhz channel given a noise floor of -97 and signals in the mid -50s, even with nothing connected on the other side of the radios. Its an efficiency issue. On Jun 8, 2015 8:13 AM, Mathew Howard <[email protected]> wrote: I kind of does, the way I understood it, that bottleneck limited you from really being able to do anything beyond what a 30mhz channel could support. Now that I think about it, I have seen 40mhz perform better than 30mhz... but yes, that was because of RF problems, and neither one was doing anything close to what it would with a good link. On Mon, Jun 8, 2015 at 11:09 AM, Josh Reynolds < [email protected] > wrote: That is a bottleneck in the system, but not relevant as far as this discussion goes. That has nothing to do with the 30/40MHz channel efficiency per say. On Jun 8, 2015 8:03 AM, Rory Conaway < [email protected] > wrote: The limitation on the older xm radios was pps.� When you added a lot of small packets and airmax, you could drop down to as low as 40Mbps.� In the real world in ptmp mode. We planned for 50mhz per AP with eveything g taken into account. Sent from fromm phone where I type with a single digit so please excuse shortcuts or typos. Rory Conaway Triad Wireless -------- Original message -------- From: Josh Reynolds < [email protected] > Date: 06/08/2015 11:59 AM (GMT-05:00) To: [email protected] Subject: Re: [AFMUG] EPMP 10 mhz vs 20mhz This. Thought it was pretty obvious but I guess I assumed too much out of some on this list ;) On Jun 8, 2015 7:33 AM, Jeremy < [email protected] > wrote: I think he is talking about using 40MHz channels on the older M series, that didn't have gig ports.� It was my understanding that the processor would get taxed as well on a 40MHz channel, making 30MHz actually work better. On Mon, Jun 8, 2015 at 9:24 AM, Josh Luthman < [email protected] > wrote: Ubnt and epmp have gig ports. Josh Luthman Office: 937-552-2340 Direct: 937-552-2343 1100 Wayne St Suite 1337 Troy, OH 45373 On Jun 8, 2015 11:20 AM, "Josh Reynolds" < [email protected] > wrote: I don't know how epmp does it. For UBNT, a 30mhz channel is just a "fat" 20mhz channel in the atheros chip. Single operation. For� a 40mhz channel, it's really two 20s, meaning radio operations are ran twice. Loss in efficiency, also marred by the lack of gigabit port. On Jun 8, 2015 7:13 AM, Mathew Howard < [email protected] > wrote: I've never seeing much difference in performance on the ubnt M series between 30mhz and 40mhz channels, so yes, I would say that is true... but I'm not sure how much applies to ePMP - they do have a much a faster processor and on a software level they are very different. So far, I have been running all of our ePMP APs on 20mhz channels and PTP links on 40mhz or 20mhz, depending on how much capacity they need. I haven't really seen much need to go down to 10mhz channels with ePMP. On Mon, Jun 8, 2015 at 8:43 AM, Shayne Lebrun < [email protected] > wrote: I seem to recall that with the M series, at least, a 30 mhz channel works 'better' than a 40 because the 40 is really two 20 mhz channels bonded together, where a 30 mhz channel is a 30 mhz channel. -----Original Message----- From: Af [mailto: [email protected] ] On Behalf Of Rory Conaway Sent: Saturday, June 6, 2015 8:32 PM To: [email protected] Subject: Re: [AFMUG] EPMP 10 mhz vs 20mhz I'm not that familiar with the ePMP's yet but I can tell you some things that we saw with Ubiquiti.� One is that channel width does not scale with bandwidth that that Atheros chipset.� For example, 40MHz channels rarely hit their theoretical maximum due to a variety of factors, noise, lower s/n, processor limitations, etc...� Second, 20MHz channels seem to be the sweet spot but even with GPS sync, you have to deal with reflections.� Third, 10MHz channels have more overhead as a percentage of total capacity and don't handle a lot of users well (above 40 for example with the older 400MHz chipsets. I'm starting to deploy XW radios with the 520MHz processors but everything is 20MHz now so I don't have a comparison).� We did see peaks of 32Mbps with some customers on 10MHz channels but that's non-peak times.� In peak times, we were seeing 8Mbps when more users were online. Rory -----Original Message----- From: Af [mailto: [email protected] ] On Behalf Of Craig House Sent: Saturday, June 06, 2015 5:20 PM To: [email protected] Subject: [AFMUG] EPMP 10 mhz vs 20mhz We have deployed 6 towers to begin our new EPMP network and 4 of those towers have a full cluster of 2.4 90 degree EPMP sectors.� They are configured with ACS turned off now because in several cases they all ended up on the same or very close to the same channel.� I have Front back designations and non overlapping channels set up on all towers.� I have tried 40 mhz 20 mhz and now 10mhz channels and while the customer stability has gotten better the more I play with settings I have kind of hit a point I dont know what else to try.� I have some that the uplink quality will vary wildly from 100% to 0%.� Most have gotten better since I went to a 10mhz channel.� Most of the customers get 12MB -30mb down in the wireless link test but the uplinks are as bad as .17.� �What is the cause of this poor uplink quality?� Is it interfernece?� My one 5ghz AP does not have this problem but even with noise many of these customers have -50 signals and oddly enough the ones with the great signals seem to be the ones that have the poorest link tests on the up link side.� I also have customes with -65 or -72 signals that get 5MB up on the same sectors?� Im scratching my head a bit on what the fix is for this?� Should I leave ACS on and change everything to 10mhz channels?� Will a full cluster with ACS on work all on the same channel? I'm used to FSK where you pick your channel and any channels that are adjacent will cause problems with connected SM's.� So am I just applying old knowledge to a technology that it doesn't apply to? Craig
