Forum Discussion
Very poor indoor signal at home
All mobile signals are reduced when you go indoors, this is the nature of radiowaves. The difference might depend on how far away the nearest mast is, and what frequency bands it has on it. On iPhone you can dial *3001#12345#* to enter field test mode and look under RAT serving cell info - under here the band number will be listed. Three have the following possibilities available (in order of lowest to highest frequency):
band 28 (700MHz) : 4G (10MHz Down 10MHz Up)
band 20 (800MHz) : 4G (5MHz Down 5MHz Up)
band 3 (1800MHz) : 4G (15MHz Down 15MHz Up)
band 1 (2100MHz) : 3G (5MHz Down 5MHz Down) + 4G (10MHz Down 10MHz Up)
-Band 28 works the best indoors but isn’t available everywhere, as this was only auctioned in 2021, and requires one of their newer sites, typically available in the same places as 5G. Rollout ahead of other networks, so if you’re lucky to live near a newer three mast you should get decent indoor coverage.
-Band20 was acquired by three around 2013, and also works indoors well, particularly since the power increase since 2022, however three (like EE) have limited capacity on this band, and is mostly used for VoLTE. Rollout is quite substantial, but some sites may still not have this band.
-Band 3 is the most common 4G band on three and provides the bulk of 4G bandwidth and has reasonable coverage indoors where the mast is not too far away
-Band 1 originally used to be all 3G but in all cases I’ve seen, it now serves 4G and 3G (soon to become all 4G), this provides additional 4G capacity but does not generally have good indoor coverage.
It’s important to note, not all mobile masts are made equal as they are installed at various points in time under various agreements sometimes with other operators, and all mobile operators share the same challenge of balancing mast density and spectrum deployment to provide coverage indoors.
Just updating my previous wiki with more recent information:
Current Band1 Configuration:
band 1 (2100MHz) : 3G/UMTS (4.8MHz Down 4.8MHz Down) + 4G/LTE (10MHz Down 10MHz Up)
OR (interim configuration on some 5G capable sites):
band 1 (2100MHz) : 3G/UMTS (4.8MHz Down 4.8MHz Down) + 5G/NR (10MHz Down 10MHz Up)
-Band 1 originally used to be all 3G, and was the first band Three way back to launch their network in 2003. 2/3 of this spectrum was previously refarmed to 4G/LTE whilst maintaining 1/2 3G, but the LTE portion is now being further refarmed to 5G/NR on newer sites which have 5G equipment.
After the 3G switch off, all of threes spectrum on band1 will become 5G/NR on a site with 5G equipment (gNB):
band 1 (2100MHz) : 5G/NR (15MHz Down 15MHz Up)
I believe three have chosen this band because
- it works very well with n78 to boost upload speeds in NR CA (for handsets that support FDD + TDD NR CA)
- cross-site and cross-RAT interference (interference between a band1 LTE mast and a band1 NR mast) can be managed well with power levels.
- many handsets are now 5G capable and when in range of band1/3, are usually are also capable of picking up n78 5G from the same site, meaning band1 LTE becomes underutilised, and therefore it no longer makes sense to keep this in an LTE configuration.
-Three may also deploy 5G solely on this band on more rural / less loaded sites, since it provides reasonable performance on its own.
Other operators are doing something similar, 2024 is turning out to be quite good news for mobile coverage and performance.
* All the above information is formulated based on my own scans of the network in recent months and observing and analysing patterns in changes on different types of sites. I don't have any inside information from Three and plans could also change. I also work in the telco industry with extensive knowledge in frequency planning and RAN deployment.
