4500 AP Radio with Force 300 CPE

We are fixing to order some EPMP 4500 5 GHz 8x8 Integrated Access Point Radios. I did read where they will be compatible with the Force 300 CPEs which is great! My question is will they do the ‘groups’ ETC properly and not comprimise the resources of the AP radio? The 200 CPEs worked with the 3000 AP radios but did not do the groups and we were told they slowed down the overall proformance of the 3000 AP to negotiate the 200 CPE. Sorry if this has been covered, I did not find anything on the forums (might have been my search string not correct?). I figure this will have only been tested by Cambium inhouse since the product is just fixing to appear available.

Thanks to all in advance!

At release (very soon here!), the 4500 series is not initially going to support backwards compatibility, that feature along with things like TDD-mode, fixed/flexible frames, GPS sync, etc. won’t be supported in firmware till later this year. At release it will most likely only support basic WLR PtMP mode with beta MU-MIMO support, and ePTP mode.

From what I’ve been told, on the 4500 8x8 AP, MU-MIMO groupings between legacy AC clients will be limited to IIRC 2 groups, while AX clients will be able to utilize up to 4 groups. A lot of the legacy AC MU-MIMO support and performance optimization is heavily based on development time and resources, so while MU-MIMO might exist at some point in a basic form, it might take longer to optimize it, with AX MU-MIMO optimization a priority.

On the e3k 4x4 AP, for legacy N SM’s, there’s actually a 3dB increase in gain due 4x4 multiplexing, which usually results in a bump up in modulation. So while they can’t participate in MU-MIMO, they can usually get a bit better modulation. I have not heard or read of any performance degradation in running mixed mode, beyond the obvious limitations of legacy N clients not being capable of 256QAM and participating in MU-MIMO.


Sort of… a F200’s highest modulation is MCS7 and it isn’t capable of MU-MIMO, so in that sense it impacts overall performance. But no more than of you have a F300 with a low signal that might only achieve MCS7, and which wasn’t benefiting from MU-MIMO grouping. That would be the same ‘impact’

The key is that’ll only be a negative hit if that SM belongs to a heavy user. Having some Force 200s out there on a 3000 AP isn’t usually a big impact, But it’s a huge deal if you sell that F200 customer a 100 Mb plan and they do 5 TB a month at MCS7 SU-MIMO on your 3000 AP. Then it’ll be a much greater impact…

So, we’ll have to wait and see how the AX APs work out, but our plan once we can get some 4500 AP’s and there is backwards compatibility) would be to upgrade our heaviest use users from F300s to F400s first. Probably upgrading the top 20% of the SMs will account for 80% of the impact.



OK and thanks for the reply. Yes on the released new hardware not being 100% software ready, so to speak. I have some of the new 4600 6GHz equipment and we were excited when they finally got us upgraded to have the DHCP working! Still many features that you would see on 3K units not available and it sounds like it will be the same with the 4500 series. Question: Will the new 4500 CPE connect and function with the 3K AP radios now? Or after they are backwards compatible? Never? My logic is if the 4500 CPE would work with the 4X4 dual horn 3K APs we are running then when we need the boost in throughput from the 4500’s we would have the CPEs already in the field.

As always, thanks in advance for the support!

If there’s no backwards compatibility then at the high price point for force 400 CPEs are at, I’d be as well looking at PMP450m or other vendor’s solution.

I’d struggle to get 1024QAM with many clients anyway so if ePMP4500 can’t give my investment in force 300 clients an 8x8 MUMIMO AP upgrade within a fixed time frame, then I’m not interested.

Like most WISPs, I’m happy to pay more for quality APs but quite honestly, I can’t fathom how bunging in an 802.11ax chipset doubles the price of CPEs.

Cambiums’ already working on beta TDD support now, so backwards compatibility will be coming just after that is somewhat stable. At the rate of development, I’d guess we’ll see backwards compatibility beta this summer. I think it’s also important to note that the F400c and F425, while they can be used as clients for the 4500 AP, they’re mainly intended for PtP use or as high end clients. The upcoming F4525 (and F4625 for 6GHz) are the “low” cost clients that most operators will be using with their e4k AP’s.

ALSO, I’ve been very surprised at how easily 1024QAM is attainable even in noisy environments with the new AX radios.


How does/is the AFC part of this work/working ? I assume the radio requires cnM in order to operate in the 6Ghz band ? Will it even operate in 5.7/8 without cnM ?

1 Like

So again, this thread is about the 4500, which is all designed to be used in the 5GHz band, so no AFC required. As to the the 4600 series, if you don’t have an FCC STA or OET to operate in 6GHz now, you can still buy and use the 4600 series but it will be locked in firmware to the 5.8GHz band. As of now, none of the e4k series requires cnMaestro to operate. I’m not an expert on AFC, but from what I’ve read, the radios only need to check in once every 24 hours to to see if a licensed user or incumbent is operating on the band, and then the AFC will block off those channels and/or reduce EIRP if needed. Both the AP and SM’s are required to having GPS, which Cambium has built support into all their 6GHz radios. I have not heard anything from Cambium about requiring cnMaestro to act as a proxy for AFC requests. This seems like simple enough thing that the radios could do it themselves, but I’m speculating at this point.

Woops , I was combing through multiple 4600 posts trying to figure out how the AFC is implemented and didn’t notice it was 4500. Thanks for the info.

Hi Eric, thanks for your detailed reply and it’s alleviated my fears about CPE costs. Looking at the spec sheets, have Cambium got a table with max TX per modulation rate and also RX sensitivity? All I can see is MCS0 and MCS11 levels on the subscriber unit. The other numbers matter too!

Worrying amount of SS MCS1 in your screencap above.

Unfortunately, I don’t have an MCS chart… maybe that’s something that @Fedor or @Chinmay_K can produce. As to the SS MCS1 rates, that’s not a problem as all broadcast traffic is sent using MCS1. You can tell this by comparing MCS1 packet % to the broadcast packet % and they’re usually within less than 1% of each other.

1 Like

AFAIK, I think that all the management frames go MCS1 (on purpose) so that probably skews the packet percentage numbers.

1 Like


Yes, we do have both.
I’ll share Max Tx Power per MCS and Sensitivity Tables for WLR/ePTP mode tomorrow.

Thank you

1 Like

Here you go!

Dynamic Tx Power limitations per MCS

The Sensitivity Table

Thank you.


It’s been over 2 months since last reply, curious if there’s an update on the backwards compatibility yet? I would like to use my 4500 however I don’t have the spectrum unless I take it from a ePMP 3000.

1 Like

Cambium has already stated backward compatibility will happen after TDD and Sync are implemented.

Ok thank you. Cambium told me almost two weeks ago that it would more than likely be working “By the time I ordered an AP and had a few 4525’s connected”. Well that time has come.

It’s going to be a little while… probably by the end of the year, which I think is probably overly optimistic. If you’d like to see a rough timeline of what to expect, check out this recent e4k webinar: