450 lineup with firmware 22

we actually had to use it for our 3 ghz because of some cbrs related issues, so far a few weeks into rolling it out seems to be working well. We have noticed that we can get more bandwidth out of the same shots in many places with the firmware 22 loaded on the ap and the sm.

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Thank you for your reply! I am seeing less throughput to SMs and higher retransmissions at the AP and all that was changed was the firmware. I can see in the Maestro performance graph reflect this same amount of bandwidth at the peak hours before the version 22 upgrade but since the upgrade performance has worsen for us. It may very well be that I am missing something or maybe a setting change from v21 to v22 but I can’t see anything that would lead me to that conclusion.

Are you using CBRS and Federated as your SAS? There have been a lot of issues with them lately and we’ve found a number of our 450 3GHz/CBRS AP’s were set to incorrect channels and/or smaller channel widths. This was causing performance issues until we realized by looking at the event logs that things had changed.

As to using R22, we’ve only had one issue so far, but performance-wise, there was a small but noticeable increase in performance over R21 that we were able to actually measure due to the addition of MGPF. The performance increase was around 10-20% depending on how loaded up the AP was and MU-MIMO groupings. It resulted in more bandwidth during peak hours, higher peaks, and higher MU-MIMO frame utilization.

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Hi,

We have also noted issues that we have sent support tickets in for. Using 5Ghz on v22 we had two specific 450m APs that would consistently drop sessions on subscribers at times between 1 -15minutes (logged errors sent to support). They are reviewing for next update. We also had an AP with significant reduced throughput to subscribers (again all on v22) on 5Ghz that when rolled back to v21 was ok again. Other 450m APs though are working well. Best to send these issues to support with the engineering files so they can review and improve. In the mean time we have some APs on v22 doing well - others on v21 and sending details to Cambium so they can review and fix.

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Thank you for your reply! No we are not using CBRS. Our throughput during peak hours on this AP is around 65mbps and my frame utilization was at 95% on V22… the night before that V21 65mbps on AP and was 40% frame utilization. I am still green with the 450m and have alot to learn but I just cannot figure it out… I am guessing it has to do with the Frame Configuration, V21 it was 85% dedicated to download now it is 61%. I must have to figure that out since v22 changed it.

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Thank you for your reply! I may have to roll back to v21 until I am more versed in the frame configuration/LTE co-locate parameters.

Are you saying that under your radio’s configuration tab, under frame configuration, that your downlink data % was changed from 85% to 61% between R21 and R22? This is quite bizarre. Assuming that you’re trying to sync with between your own radios AND someone in the area running LTE, you should try starting with the following basic settings:

Frame Period: 5ms
Max Range: 1 mile past your current farthest SM OR 1 mile past your furthest future target SM
Downlink Data: 75%
Contention Slots: 6 (or enable auto contention on 450/450i)
Broadcast Repeat Count: 0
SM Receive Target Level: -60

For further information on tuning your settings for sync with LTE, please refer to the co-location guides in the support downloads area.

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Thank you for your reply @Eric_Ozrelic

Yes it was… here is my screen…

That is what it became once v22 was implemented.

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Oh that makes more sense why your Frame Utilization changed, @DigitalMan2020! Makes sense now. (We need to remember to post on other thread too.)

Yeah this change can happen starting in release 22.0. See the Release notes section “LTE and 5G-NR colocation additions and improvements” on page 10. https://support.cambiumnetworks.com/files/pmp450/

LTE colocation feature
LTE colocation feature now automatically adjusts the allowed range of Downlink Data percentage on the APs Configuration → Radio page to ensure no overlap with LTE occurs. In previous releases, PMP 450 APs automatically adjusted the PMP frame start to ensure it aligned with that of LTE. But the selection of a proper downlink data percentage to prevent PMP downlink transmission from overlapping with the LTE uplink transmission from a nearby LTE sector was left up to the operator to use the Cambium tools to calculate and adjust it. In System Release 22.0, this computation is done in software. Also, for any existing PMP sectors already running LTE colocation, when upgrading to System Release 22.0 if the current configuration introduces overlap with LTE, the Downlink Data percentage in the Configuration → Radio page, is automatically adjusted for the operator to the nearest proper value. To use the above mentioned improvements, an operator additionally needs to specify the LTE subframe configuration in use as well as whether a normal or extended cyclic prefix is used as shown in Figure 7. Prior to System Release 22.0, only the LTE Frame configuration could be selected.
APs that were already configured for co-location prior to System Release 22.0 upgrade see their cyclic prefix defaulted to Normal and the S Frame Configuration defaulted to 7. This should be checked and changed as needed. Note that there is also a slight possibility that the downlink data percentage might be auto-adjusted based on this SSF value of 7 to an undesired value. This should also be checked and adjusted as needed. These corrections can be done directly on the AP. If a large number of sectors need to be adjusted, a small configuration template can be pushed from cnMaestro. A zip file containing 4 sample templates can be found on the Cambium Networks support site:
https://support.cambiumnetworks.com/files/pmp450
This zip file contains, in addition to a template that corrects just the special subframe after the upgrade, a template to enable co-location and set the special subframe configuration after the upgrade, a template to enable co-location prior to the upgrade, and a template to disable/backout co-location.

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Thank you for your reply… so with v22 the max Downlink data available is 61%?

We are using CBRS with Google instead of Federated in a crowded metro area, we have not seen any channel changes occur automatically on any generation of our firmware. About a year and a half ago we did have an issue with a military incumbent that put their broadcast height as miles above the earth’s surface which disabled our CBRS equipment until that was sorted out. That area has both 3.65 and 5 Ghz 450m with 450b SM’s and is where we saw the most improvement when moving to 22.

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Hi DigitalMan2020. The V22 max Downlink data available % is not restricted to 61% in general. It’s only restricted to 61% for you because you have LTE colocation enabled. It’s enabled because your Co-located Frame Configuration Option is set to " LTE frame Configuration 1" rather than “Disabled”. Are you absolutely sure that there is an LTE sector transmitting close to this AP with that LTE frame configuration? The reason you were allowed to set a larger DL data percentage with older software is because on that older software Cambium didn’t do the colocation math for you. We are doing that for you now in R22. The fact that you did not get severe performance degradation with older software while running a Downlink data percentage larger than 61% suggests to me that you do not have an LTE sector close enough to this PMP Sector to cause overlap and interference between the downlink PMP transmission and the uplink LTE transmission.

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Thank you for your reply…

I am not 100% sure or not… we have our own tower with only one 3Ghz 450m. We have several cell phone provider towers in the area offering LTE coverage and we have 1 ISP running in the 3.65 band and the tower is about 3.3km west of our tower and our Medusa faces East.

I believe (well the SA showed it) I am dealing with interference in the 3.65 band because I started with a 40mhz channel and had to narrow it to a 20mhz and had much better results at my SMs. I am unable to get ahold of anyone from the other companies so I started experimenting with co-location to see if it would help. I would like/need to use a wider channel to offer higher speeds/more customer volume so was hoping the LTE co-locator would help. Any insight or advise would be greatly appreciated! And thank you to all for commenting.

I’d suggest that you start out with the settings I suggested above first, and without using any LTE collocation settings. Watch performance over a night or two. Then, start out with (arguably) the most common LTE settings which is LTE TDD mode 2 (75%) and SSF7 and again, watch performance over a night or two. Then try TDD mode 2, and SSF5. Then TDD mode 3 and SSF7, then TTD mode 3 and SSF5. From their you can try more settings/combinations, but without knowing exactly what settings they’re using, it may be difficult/time consuming for you to find the right sync settings.

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Thank you @Eric_Ozrelic, I will definitely do as you suggested. Really appreciate the insight and suggestions. :beers:

I may have to roll back to v21 until I am more versed in the frame configuration/LTE co-locate parameters.

I believe (well the SA showed it) I am dealing with interference in the 3.65 band because I started with a 40mhz channel and had to narrow it to a 20mhz and had much better results at my SMs. I am unable to get ahold of anyone from the other companies so I started experimenting with co-location to see if it would help. I would like/need to use a wider channel to offer higher speeds/more customer volume so was hoping the LTE co-locator would help. Any insight or advise would be greatly appreciated! And thank you to all for commenting.

The best way to go about sync-ing with an LTE provider is to work with them to get their settings and then use Cambium’s LTE coexistence tools to match. If you cannot find the LTE operator or they won’t discuss settings with you, then you’ll have to try settings. Take a look at my posts in this thread for some good starting points.

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So I tried your suggestions above and I do not think I need to have any colocation enabled. So I set if to disabled, 5ms, 6 for contention slots, 85% for Downlink, Broadcast Repeat count 2.

So we have 1 Cellular Tower near our tower running 5G. I am not sure if they are an issue for us. We have 5 subs right now and only one seems to have issues…

it normally sits here but does change intermittently, Signal to Noise gets worse then recovers…

Here is the SA of the SM in question…

Here are the AP sounding, the SM in question is the not eligible/untrusted

I am not sure why it is “not eligible and untrusted”. Is this interference? If so would not other SMs be having issues… especially LUID 2 as it is just a couple houses down from LUID 4. I have swapped radios and same results.

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