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4G Band 20 Only / VoLTE
I am using the Huawei B818-263 router and using LTE H-Monitor it seems that my router is connecting to:

CellId: 131306260
eNB Id: 512915

From CellMapper it looks like this Vodafone eNB supports only band 20?

Cell Mapper Link

And looking at the surrounding cells, they all seem to be only band 20?

Does this mean that I cannot benefit from carrier aggregation to make use of multiple bands at the same time? 

By the way I get 50Mbit/s download and 12Mbit/s upload with the stats:

Wireless transmit power
PPusch:17dBm PPucch:2dBm PSrs:0dBm PPrach:4dBm
Uplink mod/demod of MCS
Downlink mod/demod of MCS
mcsDownCarrier1Code0:24 mcsDownCarrier1Code1:20

I suppose that is plenty fast I am simply being greedy, but I am curious whether I can increase the speeds at all.

Also I am wondering about VoLTE. Whenever I make or receive a call using the RJ11 socket on my router and connected analogue phone, the router drops from 4G to 3G, and then when I have finished my call it goes back to 4G. I spoke with Huawei about this and they indicate that UK mobile operators whitelist devices for VoLTE (and that this whitelist does not include routers). Would spoofing the device reported to the eNB mean that I could get VoLTE to work with this router, if such a practice is technically possible, e.g. through a firmware modification or so?

An alternative solution would be to hook up a VOIP adapter and use VOIP, but ideally I would like to use the call plan with the SIM connected to the router. Is it possible to access VOIP / SIP settings for a mobile SIM to call as if from that SIM using VOIP? That would circumvent the drop to 3G whilst still allowing me use of the call plan associated with the SIM inside the router.
50Mbps is very good for a band 20 cell, particularly if you are getting this at peak time. Here in Ireland, very few band 20 only cells can deliver a similar speed except in the middle of the night due to high contention across the networks.

To check if you can pick up other bands, go into Configuration -> Radio, select Manual for LTE band mode and choose all the bands except band 20. This will force the router to connect on another 4G band, regardless of how weak it is. I suggest trying this with the router outside on a dry day as the high frequency bands don't penetrate walls very well.

If it connects on another band, move the router about to try getting the SINR as high as possible and run a few speed tests to see how it compares (ignore the upload speed for now). If the download speed is decent, you can get a directional outdoor antenna to improve the signal, such as the Poynting XPOL-A0002 or the XPOL-2-5G (higher gain, but more expensive). I'm not sure if Vodafone UK supports carrier aggregation between masts, so you may need to leave band 20 deselected to connect to distant cells on the other higher bandwidth bands. Going by Wikipedia, Vodafone UK uses bands 1, 3, 7, 20, 32 and 38.

For VoLTE, I'm currently not aware of any way to get it to work on a router. Here in Ireland, Vodafone does a similar means of whitelisting and even when I had a VoLTE capable phone, it would not work as it was not a model approved for VoLTE by Vodafone. While VoLTE is IP based, it uses a different means of connecting than traditional VoIP and is established separate to the existing APN data connection. This article shows how a VoLTE call is established.
Thanks for the helpful response. Frustrating about VoLTE, but it does have the one benefit that it forces me to block incoming calls (by selecting 4G only in the router configuration page) for important videoconferencing meetings. Some routers accept a coupling to a phone which provides the internet. But then I would lose the capability to use my nice POTS cordless phones, which would seem a shame.

I had a look and identified some modified firmware for some Huawei routers. Just out of intellectual curiosity, and as a hypothetical scenario, would altering the IMEI to that of, say, my mobile, make VoLTE work (assuming whitelisting capabilities is by IMEI?)

Would it be possible to try an outside test on my mobile phone? Is there a way to see which bands a mobile is connected to? We have extremely thick walls and trying to ascertain how I would make use of an external antenna is not so easy. I could perhaps try to locate the router in our garage and use an external antenna that way, although then I'd have to worry about getting wi-fi through to the house.

The 50Mbit/s download and 12-16Mbit/s upload seems very consistent. This is in the Scottish Highlands so I suppose there is very low usage of the nearby masts. I tried to set up a 4G router for my Mum in Edinburgh, but the results were dire. Really low SINR (negative) and bandwidth would fluctuate between unusable and 20Mbit/s download and 5Mbit/s upload. Is that because of congestion in Edinburgh do you think?

Any idea if there is a way I could get my router with a sort of UPS to stop it losing power in the event of a power outage? Or perhaps for that situation I should buy a cheap 4G dongle and take out SIM card and plug it into that?
As the IMEI number identifies the device type, setting the router's IMEI to that of a VoLTE enabled phone might work. The downside is the risk of bricking your router if the firmware fails to flash, especially with how expensive the B818 is. I bricked a 4G USB modem a while back trying to flash firmware to debrand it. The utility crashed out while flashing the bootloader.

You can try testing with a phone on the same network. If your phone is Android based, download the App Network Cell Info Lite and this will show the bands it's connected to and the readings. With a Samsung phone, you can dial *#0011# to view the band readings.

Another option is to take your router outside on a dry day (with a long extension lead) and test it on a window sill on each side of the house. You can use the App huaCtrl to view the signal readings and test specific bands.

The negative SINR at your Mum's place indicates a lot of interference. This is more due to being in-between two or more masts than just high congestion. You can moving the router about to see if there is a spot where the SINR remains positive as there are likely spots where the router picks up better reception from the desired mast than interference from unwanted masts. Otherwise I suggest installing a directional outdoor antenna.

For powering during a power cut, you can try getting a USB 5v to 12v 5.5mm DC adapter (like this), which plugs into a power bank and provides 12v. I'm not sure if it will provide enough power for the B818, however, it is able to power the my Huawei B525 router. A small PC UPS would be another option as you could plug your DECT base into it also for telephone calls during a power cut.
Seán would you be able to recommend an indoor antenna for me to use with this modem (just to try)? I realise I may not get much of a speed gain, but I have terribly thick walls and getting external antenna routed through is not so practical for me. I wonder if placing these indoor antennas right next to the window (on the 80cm or so window shelf) might help. 

I tried placing the B818-263 on the shelf and that resulted in a modest increase in download and a large increase in upload (to 25Mbps from 15Mbps).

I wonder about this one:

Or could I buy a directional antenna and have it pointed towards the tower through the wall? 

What are your thoughts on either option and what would you recommend?
Unfortunately, indoor antennae generally don't provide any benefit over what the router can pick up in the same spot. The exception would be if you could place the antenna in the loft where the signal does not need to pass through a thick outer wall.

One option for the window would be to get a feed-through kit. This doesn't require any drilling or modification to the window and you can easily remove the kit. With the window open, you can feed this through any side of the window, then close the window on it to secure in place. The outdoor antenna leads connect to the outside connectors of the feed-through leads. For inside, you can use a short pair of SMA to TS9 leads to attach to your B818 router.

Window SMA feed through kit (2 x 50cm):

SMA to TS9 (2 x 30cm):

Directional MIMO antenna with 2 x 10m leads:

This antenna will also work in the loft if you prefer to keep it indoors. You can install it on a TV antenna mounting pole. For a temporary set up, I suggest using something like a camera tripod or washing line pole to determine which way it needs to point before mounting it outside on a wall.
Thanks for your response. Good to know if I do make the jump to external antenna.

Actually the performance with the router on the window sill seems really good (50-60Mbps DL; 25Mbps UL). Even if the omnidirectional antennas could approximate that, I think that would be good enough for what we need. I just want to avoid having the router itself on the window sill because the trailing wires (router power cable + ethernet + phone cable) look a bit unsightly. 

If I were to buy the two upright omnidirectional antennas just to try, how would these be optimally placed? Should they be a certain distance apart or does it not matter? I presume the internal antennas are all just vertical and only spaced apart by a small amount. Do you know if the B818-263 (4x4 MIMO support?) would then use its own antennas + the two external antennas? Does MIMO work on a single band? I would be interested to know about how all of this works with external antennas.
4G 2x2 MIMO consists of two circular polarisation signals transmitted 90 degrees out of phase. The common way to receive these with an external antenna is to have one antenna vertical and the second one horizontal, i.e. as the vertical antenna picks up one signal, the horizontal antenna simultaneously picks up the cross-polarised signal (i.e. 90 degrees offset). This also works with the antenna positioned +/- 45 degree angles.

With how narrow the B818 router is, it likely uses circular polarised antennae much like an omni-directional MIMO antennae that looks like a short white pole. For 4x4 MIMO, the second pair of antenna are positioned about a half-wave length apart from the main antenna pair. These additional antennae only pick up high frequencies (>1700MHz), so it only uses 4x4 MIMO for the higher frequency bands, where the mast also operates on 4x4 MIMO.

With that magnetic antenna pair, I reckon it will only work with one polarisation as there does not appear to be any way to tilt either antenna, i.e. the router will likely pick up no signal on the cross-polarised signal on the second antenna port. What you can try is positioning one sideways, such as clicking the magnetic base to any steel surface on the left or right of the window.
I tried the internal antennas. They worked well in the sense that by putting them against the window I got download to ~70Mbit/s and upload to ~30Mbit/s, but I returned them ultimately owing to aesthetics in my office.

So right now I get between 40-60Mbit/s download and 10-16Mbit/s upload and on LTE H-Monitor having tweaked the position of the router I see:

SINR: 16.0 dB
RSRQ -5.0 dB [oscillates between -4 and -10]
RSRP -94 dBm
RSSI: -81 dBm

Is RSRP at this level of concern in terms of sustaining a reliable connection? I need to be able to retain reliable bandwidth for videoconferencing for my work.
The RSRP level is fine, particularly if it's stable. If you see it dip below -100dBm, then there is a risk it could affect the stability as the upload speed deteriorates rapidly for every dB below -100dBm.

Based on your RSRQ being within -10dB most of the time, it looks like the cell you're connected to has low traffic load. This figure fluctuates according to the traffic load on the mast, with -12dB being fully loaded. It dips further with noise and interference with -19.5dB being at the edge.
(12/01/2021, 08:59 PM)Seán Wrote: The RSRP level is fine, particularly if it's stable.  If you see it dip below -100dBm, then there is a risk it could affect the stability as the upload speed deteriorates rapidly for every dB below -100dBm. 

Based on your RSRQ being within -10dB most of the time, it looks like the cell you're connected to has low traffic load.  This figure fluctuates according to the traffic load on the mast, with -12dB being fully loaded.  It dips further with noise and interference with -19.5dB being at the edge.

Thanks for the info. As I write this now the readings are: 


And yet I've noticed that especially at night I get big bandwidth swings. So for example download bandwidth can drop to between 10 and 20 Mbit/s (upload 8-10), whereas in the morning I have seen download at 60 Mbit/s (upload 17).

Any idea what might be the cause of this bandwidth fluctuation?
Your readings are very good for the time of evening. While this means there's not much load on your mast, it looks like the bottleneck is with a backhaul link to that mast as most rural masts rely on microwave backhaul links to other masts.
You are right. I checked with my mobile phone by holding it outside the window. I get 80Mbit/s download at best and it drops to something like 30Mbit/s at worst. 

Overall I have been extremely happy with the 4G experience. 4G in the Highlands significantly better than fibre broadband in the the Peak District. 

Isn't it such a pity that mobile operators do not release VOIP settings to access calls that way? Vodafone allows Alexa calling so it's obviously easily done. 

Sean you have two routers to deal with VOIP. Couldn't you just use some form of quality control to ensure VOIP is prioritised on your main router? Also since you have two routers can you multiplex to get more bandwidth? Win 10 has a facility to combine multiple connections i thought.
Unfortunately, QoS is practically unusable with 4G or any type of wireless ISP where the bandwidth is unpredictable. Generally with a QoS capable router, it throttles the incoming and outgoing data rates just below the available bandwidth to prevent buffer bloat for the prioritised data. With a wireless ISP with unpredictable bandwidth, it is unable to prevent buffer bloat especially on the downlink.

Up until about a year ago, I was able to use the VoIP reliably with just occasional glitches. However, since the start of the pandemic when Internet usage shot up, we had to stop all Internet activity whenever a phone call took place each evening. Even YouTube streaming kept interrupting VoIP and this is despite the Fritz Box giving VoIP highest priority. If Windows or some other application decided to download updates, it totally killed the VoIP call.

By moving the VoIP to a separate router, this gives it its own timeslot on the cellular network. No amount of traffic on my main router will affect the VoIP as any incoming data backlog (i.e. bufferbloat) will just affect the timeslots allocated to the main Internet connection. The VoIP 4G router may end up with fewer time slots on the cell, but it just needs enough to provide 64Kbps each direction. Unlike the main router, there is no risk of a download or upload suddenly taking up its available timeslots. This of course assumes that we don't use this second router for any other purpose other than VoIP.

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