RM500Q-GL Only doing 2CA

HI I have just received one of these and was getting excited about getting at least better 4g bandwidth until 5G rolls into town.

I have firmware RM500QGLABR11A03M4G and have got the device working on 3 in the UK using the 3internet APN. It works and I can push data around which is great - but I’m only getting 25Mbps - qmicli reports even under heavy load it is only joining one additional cell which gives me 10 + 15 DL bandwidth and so all is in agreement

My question is why is it only aggregating 2 links? It’s currently slightly slower than my 20 quid cat4 usb stick which is a bit disappointing - I was hoping for a stepping stone of cat 16/20 getting me closer to 100Mbps until 5G is working.

I’m hoping someone can call me a noob and explain some simple config to unlock all those extra links?

fingers crossed!

Oh and I know my tower does support more as I can get 100mbps on my cat 16 phone without gigantic anttenna on it!

Hi, John_Rogers:
At present, RM500Q-GL series products have a maximum capacity of 3CA;If your module is registered on a 5G network, it’s easy to reach speeds of 100Mbps.If your module is not capable of implementing 3CA, it may have something to do with the radio environment around you and the ability of the service provider to support multi-CA.

Hi Herbert - at present we are in an area with very weak 5G but a mast is going up in the coming months very close by. We currently have a cable connection and backup 4g cat4 dongle which gives us around 35Mbps.

The thing that surprises me is that the RM500Q-GL is getting a slower speed (~25Mbps) in LTE mode than this cheap dongle in the same radio environment even though it has the benefit of larger antennae. My Cat16 phone in the same spot gets around 100Mbps off an LTE connection so I do think there is something not optimally setup for an LTE only environment in the firmware or settings I am using on the RM500Q-GL.

Ultimately it is a bit academic as we will eventually get 5G and I’m expecting several hundreds of Mbps at that point. I’ll certainly be back on here if it’s only 100 then!

You’ve offered to send me an older firmware on a different thread which seems to be able to support 5CA in LTE and hopefully that will sort out the LTE only problem

Hi,John_Rogers:
Your module download rate is slower than your phone’s, the two are not comparable;The slow download rate is affected by many factors, such as the download server you use, download resources, radio quality, external accessories (MCU, etc.),and the current base station cell access number of users;
You can also test your 4G network speed by downloading large data packets (larger than 1 gigabyte). You may also want to set up your test software (the number of packets that can be downloaded at one time, the number of threads that can be downloaded, etc.) to see if your network speed improves!
Because 5G uses more spectrum bandwidth than 4G, and its encoding and modulation methods are more powerful,so 5G’s speeds will be higher!

Hi - I’m just using the standard speedtest client in each case - it’s very reliable especially over multiple tests and the module is never connecting more than 1 secondary cell connection and never achieving more than 25Mbps my cat16 phone rarely gets less than 100 off the same tower. There really is something decidedly non optimal about the setup of the module for this carrier in lte mode.

Digging a little deeper I note that it is defaulting to connecting on band 1 whereas for my carrier (3UK) band 3 is the default - If I remove band 1 from the list of allowed bands then it will connect on band 3 but then refuses to perform carrier aggregation at all.

It looks that the list of carrier aggregation combinations does not cover the offerings of this network which is 3,20,1,32. The standard 4g+ combination is 3 + 20 but the module will never select that combination, at best it selects 1 + 3.

Is there some AT commands to encourage different CA combinations?

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Just to highlight when it is using 1+3 combination I get 25Mbps when using 3 alone I get 30. I can also force a connection on band 20 or 32 to the same tower indicating that 3 or even 4 CA should be possible at this location but the only CA I can get is 1+3 and that is not the carriers standard profile - it should be choosing 3+20 as the basic 4g+ combination.

This strikes me as a config issue more than anything else.

What is the exact model of your card? There seems to be a CA&ENDC document. Ours are RM500QGLAB-M20-SGASA and seem to right now just support 3CA instead of 5CA. I was also not able to find the reason for that yet or if this can be fixed.

Not sure how I get that much detail on the device? The most I get from AT commands is RM500Q_VH

My firmware is RM500QGLABR11A03M4G - There is a suggestion that the version 10 firmwares do better at CA on another thread

It is printed on the card surface. I think it is not possible to downgrade. However, it will be interesting if this is a bug, feature cut or working as designed.

Ah that information is now buried under a heat sink in my device.

The suggestion on the other thread is that there is a feature cut between the CS and general release firmware to differentiate the 500 from 502, but I’m not even getting the 3CA which is apparently part of the capabilities of the release firmware - infact even 2CA isn’t working properly for my carrier. Perhaps the feature cut didn’t go well!

Find out the Digi-Key Part Number or Manufacturer Part Number. You could ask your supplier too.
And then I think sourcing the CA&ENDC document is one more step closer to solving this.

Hi is there any chance to get the CA&ENDC document for the RM500Q_GL ? It would be great to get to the bottom of this

Hi - I now have a 5G signal - whoop. However I’m still getting very slow speeds ( ~20Mbps )
qmicli --device=/dev/cdc-wdm0 --nas-get-tx-rx-info=5gnr
[/dev/cdc-wdm0] Successfully got TX/RX info
RX Chain 0:
Radio tuned: ‘yes’
Power: ‘-103.4 dBm’
ECIO: ‘-12.0 dB’
RSRP: ‘-115.4 dBm’
Phase: ‘0.00 degrees’
RX Chain 1:
Radio tuned: ‘yes’
Power: ‘-102.3 dBm’
ECIO: ‘-11.7 dB’
RSRP: ‘-113.9 dBm’
Phase: ‘0.00 degrees’
TX:
In traffic: ‘yes’
Power: ‘0.0 dBm’

Is the reception on the 5G too low? I see RSRP goes down to -140, but clearly -114 is pretty low.

In case this helps anyone - I think this is down to some funny config in the firmware - By setting the LTE category of the modem back to 18 ( from 24 ) using AT+QCFG=“hsdpacat”,18 I am able to get 5CA and speeds of 80+Mbps in LTE mode - a very welcome 3-4 times boost. Essentially mirroring what I would expect from a decent LTE+ phone to the same 4g tower. (albeit still using the wrong bands for my carrier, but this seems to have a relatively minor impact)

For anyone else who is having this problem - 5G is the answer - they finally turned it on near me and I’m getting 4CA on 5G and 400 odd Mbps - the bottom line is it’s not a great LTE+ modem ( fixable as in my last post ) - but it’s brilliant at 5G out of the box.