MIkrotik SXT-LTE6 Carrier Aggregation with Three UK

HI,
I am having a Three UK SIM in MIkrotik SXT-LTE6 and when I select all bands I get CA with
Prim Band : Band 20
CA Band: Band 3
This gives me good download speed, but the upload is really slow - as its using Band 20

However when I force Band 3 as my primary band via CLI, I dont get any other band in CA.

I understand SXT LTE6 can do following combinations:
1+1/5/8/20
3+3/5/7/8/20
apart from other combinations that are not relevant to 3UK.

Has anyone got CA with Band 1 or Band 3 as primary and Band 20 as CA?
Or Band 1+1 or Band 3+3 in CA?

Is this limitation from my local mast or something to do with SXT-LTE6, appreciate if you could share your experiences.

I don't think you can have band 1+1, or band 3+3 on Three as they only have one chunk of spectrum for these bands.

Band 3 + 20 is a setup which many people including me have used so it can work in certain locations. However, i had the reverse experience in that band 20 could not be primary if you wanted CA. CA would only activate if band 3 was primary. In my case this was because the bands were across two cell sites (masts) and not being broadcast from the same location. The band 20 cell must have not had the technology I assume.

When 3 upgraded my local band 3 mast, they also added band 1 support. From that day band 20 was not available for CA. Either because they decided that's how they wanted it or because the equipment was incompatible between the two sites. My Hauwei B525 could not CA with bands 1 & 3 so I could not try,

Can you not just put the selection to automatic and let the cell and your device deal with bands and see if this gives you what you want?

Edited by gary333 (Thu 09-Jul-20 15:12:03)

For me, i think the signal is coming from same mast . The mast that I connect to has Band 1,3 and 20. I have checked on my mobile, when I am outside, the CA happens on Band 1+3.

Coming back to Mikrotik - if i leave it to automatic - it connects to Band20 as primary and Band 3 as CA band.

As three tech support is non existent so my complaint/query has been quietly ignored.

Hi guys, sorry to hijack thread but I'm intrigued by the compatibility of channels that will bond together?

Anybody know where I can find the compatible pairs for my B535?

I'm currently connection with Smarty(3) primary band seems to be B1(2100) and guessing its getting CA as it says LTE+ ....

Question is that above mentioned 1+3 is capable, I can't imagine that 1+20 would give me the bandwidth I have so guessing I'm either getting 1+1 between two towers (if possible) or compatibility is different across chips.

In reply to a post by mlmclaren:

Hi guys, sorry to hijack thread but I'm intrigued by the compatibility of channels that will bond together?

Anybody know where I can find the compatible pairs for my B535?

I'm currently connection with Smarty(3) primary band seems to be B1(2100) and guessing its getting CA as it says LTE+ ....

Question is that above mentioned 1+3 is capable, I can't imagine that 1+20 would give me the bandwidth I have so guessing I'm either getting 1+1 between two towers (if possible) or compatibility is different across chips.

B535 supports bands 1+3 so could be that. It won’t be overlap on same band across cells.

B535-232 support:
LTE: B1/B3/B7/B8/B20/B28/B32/B38
Intra-band: B1+B3, B1+B7, B1+B8, B1+B20, B1+B28, B3+B7, B3+B8, B3+B20, B3+B28, B7+B8, B7+B20, B7+B28, B8+B32, B8+B38, B20+B32, B20+B38, B28+B38
Intra-band (unknown): B3+B3

In reply to a post by kams19:

For me, i think the signal is coming from same mast . The mast that I connect to has Band 1,3 and 20. I have checked on my mobile, when I am outside, the CA happens on Band 1+3.

Coming back to Mikrotik - if i leave it to automatic - it connects to Band20 as primary and Band 3 as CA band.

As three tech support is non existent so my complaint/query has been quietly ignored.

Three support will only support products they have sold, they will ignore you talking about a Mikrotik.

On Three (and EE) Band 20 only have 5Mhz of capacity, compared to 15Mhz of Band 3, and 20Mhz on Band 1.

so to CA 1+3 is giving you 35 Mhz. To CA 3+20 will give you 20 Mhz, plus potentially deprive some indoor person of enough signal to make a phone call.

So you really want to tweak that Mikrotik to get Band 1, as if you have 1 or 3, there is more capacity on band 1.

In reply to a post by mlmclaren:

Hi guys, sorry to hijack thread but I'm intrigued by the compatibility of channels that will bond together?Anybody know where I can find the compatible pairs for my B535?

Normally in the documentation that comes with the product. Huawei products are generally BADLY documented sadly. Also it might depend if it has vendor firmware.

I'm currently connection with Smarty(3) primary band seems to be B1(2100) and guessing its getting CA as it says LTE+ ....

It is more likely, but "LTE+" is a logo that means "LTE-Advanced" which means one of a bunch of technologies that include CA, and also include higher order QAM features etc.

Question is that above mentioned 1+3 is capable, I can't imagine that 1+20 would give me the bandwidth I have so guessing I'm either getting 1+1 between two towers (if possible) or compatibility is different across chips.

I don't think you can CA between cell sectors. What you call a tower (US term) will be a mast with antenna panels pointing in various directions. The large ones generally have three sectors, and so on a single mast, you can have three cell sectors transmitting, and your device will hear all of them, at different strengths.

Buildings, monopoles and other mast types can have 1, 2 or 3 sectors generally. If there are more, you might have two masts. This is used in towns to solve holes in coverage. There is more info at https://pedroc.co.uk

In reply to a post by jchamier:

In reply to a post by mlmclaren:

Question is that above mentioned 1+3 is capable, I can't imagine that 1+20 would give me the bandwidth I have so guessing I'm either getting 1+1 between two towers (if possible) or compatibility is different across chips.

I don't think you can CA between cell sectors. What you call a tower (US term) will be a mast with antenna panels pointing in various directions. The large ones generally have three sectors, and so on a single mast, you can have three cell sectors transmitting, and your device will hear all of them, at different strengths.

Buildings, monopoles and other mast types can have 1, 2 or 3 sectors generally. If there are more, you might have two masts. This is used in towns to solve holes in coverage. There is more info at https://pedroc.co.uk

I suspect your quotes are broken, and hence can't see your reply.

Meh..

Gist of the reply was, I've not long returned from couple years in north america, hence still banding around slurs like tower haha.

and I've just switched back to EE sim, Smarty sim bailed on me around 17:30, tower must not be dealing well with passing traffic or something, also although EE and Three sharing masts around here, EE has a big 3 sector on top of a block of flats about 1KM away and a sector points my direction so I'm able to get good bandwdith from that (when its operating optimally.

I am however 1KM away and in a dip so my modem/router is in the loft and hanging on between 105-110 on the RSRP at B7, until just this second where the mast seems to have gone .... up and now I've been bounced to the MBNL mast about 1.2KM away....

In reply to a post by mlmclaren:

Gist of the reply was, I've not long returned from couple years in north america, hence still banding around slurs like tower haha.

No worries, I have family in the US, just worth bearing in mind when looking at information sites. The mobile (cell) networks are quite different, the US seems to have more CA as they had a lot more 5 Mhz and 10 Mhz blocks than we have.

and I've just switched back to EE sim, Smarty sim bailed on me around 17:30, tower must not be dealing well with passing traffic or something, also although EE and Three sharing masts around here, EE has a big 3 sector on top of a block of flats about 1KM away and a sector points my direction so I'm able to get good bandwdith from that (when its operating optimally.

With 4G, (and 2G EE only) the sharing for EE and Three is only really the location, and often the antenna panels. They have separate radio units (in the cabinets at the base) and separate backhaul networks. (With 3G they shared more, but this is less important as 3G is phased out).

I am however 1KM away and in a dip so my modem/router is in the loft and hanging on between 105-110 on the RSRP at B7, until just this second where the mast seems to have gone .... up and now I've been bounced to the MBNL mast about 1.2KM away....

105 to 110 is not a bad indoors number, quite normal to see between those indoors, and on Band 7 that is very good as 2600 Mhz is usually an addition for capacity, often in town centres. My parents are able to get B7 indoors as well as two carriers of B3, and it means their phones often show 1 bar signal strength, so they think they have poor service, when in fact they have better than most people (3 carriers in all parts of their home).

The "MBNL" company is an infrastructure and people share, the physical mast could be easily owned by Arqiva (or whomever they've just sold them all to) or a land owner. Same with "Cornerstone" for O2 and Vodafone.

Didnt knew that Band1 is having 20Mhz, i can manually set it to always connect to Band 1.
In past when it connected to Band 1, i have seen the uploads are lower than Band 3..

I wish MIkrotik had supported Band 1 + 3, would had been amazing combination for 3 customers.

Edit - just found on the Mikrotik: B1@10Mhz earfcn: 99 phy-cellid: 311

Edited by kams19 (Thu 09-Jul-20 23:10:51)

In reply to a post by kams19:

Edit - just found on the Mikrotik: B1@10Mhz earfcn: 99 phy-cellid: 311

Ok, it will be different in different areas of the country. I gather lots are 10, apologies.

Hi Kams,
I'm just looking at doing a similar setup with the exact same modem kit.
When you say your getting good download speed what are you actually achieving?
I get anywhere between 40 and 80mbps on my phone or desktop with the current Three supplied Huawei router but they seem to be fickle beasts and regularly break down so looking for a decent quality upgrade.
Be good to hear what your getting.
Thanks