I was attending the IEEE 5G World Forum live-stream, courtesy of IEEE Tv and happen to hear Egil Gronstad, Senior Director of Technology Development and Strategy at T-Mobile USA. He said that they will be building a nationwide 5G network that will initially be based on 600 MHz band.
During the Q&A, Egil mentioned that because of the way the USA has different markets, on average they have 31 MHz of 600 MHz (Band 71). The minimum is 20 MHz and the maximum is 50 MHz.
So I started wondering how would they launch 4G & 5G in the same band for nationwide coverage? They have a good video on their 5G vision but that is of course probably going to come few years down the line.
In simple terms, they will first deploy what is known as Option 3 or EN-DC. If you want a quick refresher on different options, you may want to jump to my tutorial on this topic at 3G4G here.
The Master Node (recall dual connectivity for LTE, Release-12. See here) is an eNodeB. As with any LTE node, it can take bandwidths from 1.4 MHz to 20 MHz. So the minimum bandwidth for LTE node is 1.4 MHz.
The Secondary Node is a gNodeB. Looking at 3GPP TS 38.101-1, Table 5.3.5-1 Channel bandwidths for each NR band, I can see that for band 71
The minimum bandwidth is 5MHz. Of course this is paired spectrum for FDD band but the point I am making here is that you need just 6.4 MHz minimum to be able to support the Non-Standalone 5G option.
I am sure you can guess that the speeds will not really be 5G speeds with this amount of bandwidth but I am looking forward to all these kind of complaints in the initial phase of 5G network rollout.
I dont know what bandwidths T-Mobile will be using but we will see at least 10MHz of NR in case where the total spectrum is 20 MHz and 20 MHz of NR where the total spectrum is 50 MHz.
If you look at the earlier requirements list, the number being thrown about for bandwidth was 100 MHz for below 6 GHz and up to 1 GHz bandwidth for spectrum above 6 GHz. Don't think there was a hard and fast requirement though.
Happy to hear your thoughts.
During the Q&A, Egil mentioned that because of the way the USA has different markets, on average they have 31 MHz of 600 MHz (Band 71). The minimum is 20 MHz and the maximum is 50 MHz.
So I started wondering how would they launch 4G & 5G in the same band for nationwide coverage? They have a good video on their 5G vision but that is of course probably going to come few years down the line.
The Master Node (recall dual connectivity for LTE, Release-12. See here) is an eNodeB. As with any LTE node, it can take bandwidths from 1.4 MHz to 20 MHz. So the minimum bandwidth for LTE node is 1.4 MHz.
The Secondary Node is a gNodeB. Looking at 3GPP TS 38.101-1, Table 5.3.5-1 Channel bandwidths for each NR band, I can see that for band 71
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NR band / SCS
/ UE Channel bandwidth
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||||||||||||
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NR Band
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SCS
kHz
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5 MHz
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101,2
MHz
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152
MHz
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202
MHz
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252
MHz
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30 MHz
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40 MHz
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50 MHz
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60 MHz
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80 MHz
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90 MHz
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100 MHz
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n71
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15
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Yes
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Yes
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Yes
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Yes
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30
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Yes
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Yes
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Yes
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|
|
|
|
|
|
|
|
|
|
60
|
|
|
|
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The minimum bandwidth is 5MHz. Of course this is paired spectrum for FDD band but the point I am making here is that you need just 6.4 MHz minimum to be able to support the Non-Standalone 5G option.
I am sure you can guess that the speeds will not really be 5G speeds with this amount of bandwidth but I am looking forward to all these kind of complaints in the initial phase of 5G network rollout.
I dont know what bandwidths T-Mobile will be using but we will see at least 10MHz of NR in case where the total spectrum is 20 MHz and 20 MHz of NR where the total spectrum is 50 MHz.
If you look at the earlier requirements list, the number being thrown about for bandwidth was 100 MHz for below 6 GHz and up to 1 GHz bandwidth for spectrum above 6 GHz. Don't think there was a hard and fast requirement though.
Happy to hear your thoughts.
2 comments:
"If you look at the earlier requirements list, the number being thrown about for bandwidth was
100 MHz for below 6 GHz and up to 1 GHz bandwidth for spectrum above 6 GHz. Don't think there
was a hard and fast requirement though."
Practicalities.
Getting 100MHz of contiguous bandwidtb in the [0,3) / [3,6) GHz bands
is going to be very difficult as that is the most coveted spectrum
for a multitude of RATs.
In the true mmWave bands, this should be easier to do.
With 5G NR you could mitigate against this due to the fact
that the SSB can be miles away in the spectrum from the BWPs.
Which means :
1. Contiguous bandwidth is not necessarily a must
2. UE initial signal acquisition time/power costs are traded for
BWP flexibility.
And of course you are forced to use the higher OFDM SCS (60KHz + )
in the [6,53) GHz band.
I think it is much simpler than that: They will deploy some form of LTE and call it 5G :)
Joking aside, there will be practically little difference in 600 MHz between the LTE and 5G on the access side. The difference is higher in 2.5, 3.5 and up where massive MIMO and beamforming can be deployed.
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