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In NR, there are roughly two large frequency range specified in 3GPP. One is what we usually call (sub 6 Ghz) and the other is what we usually call millimeter wave. Depending on the ranges, the maximum bandwidth and subcarrier spacing varies. In sub 6 Ghz, the maximum bandwidth is 100 Mhz and in millimeter wave range the maximum bandwidth is 400 Mhz. Some subcarrier spacing (15, 30 Khz) can be used only in Sub 6 Ghz and some subcarrier spacing (120 Khz) can be used in millimeter wave range only, and some subcarrier spacing (60 Khz) can be used both in sub 6 Ghz and millimeter wave range.
Followings are the list of topics to be covered here. Not so much explanations in this page. they are mostly bunch of tables, but you would refer to these tables very often once you start developing (especially testing) NR devices. I just wanted to put togather those tables in single page, so that you can easily find the information. Most of the tables shown in this page are from 38.101-1 and 38.101-2.
As mentioned above, two types of frequency range is defined in 3GPP. Sub 6 Ghz range is called FR1 and millimiter wave range is called FR2. The exact frequency range for FR1(sub 6 Ghz) and FR2 (millimeter wave) are defined as below.
< 38.101-1 Table 5.1-1: Definition of frequency ranges >
< Based on 38.101-1 Table 5.2-1: NR operating bands in FR1 >
< based on 38.104 Table 5.2-2: NR operating bands in FR2 >
< 38.101-1 Figure 5.3.3-1 Definition of channel bandwidth and transmission bandwidth configuration for one NR channel >
This illustration would look obvious saying 'Channel BW = Maximum transmission bandwidth + guardbands on both side', but when you look at the tables below it may not look clear since the maximum transmission bandwidth is specified in the unit of RB and the guardband band is specified in the unit of khz.
To make things clear on this, my Japanese friend Tanaka Junya came up with a simple equation and example as follows.
Channel Bandwidth(CBW) is about [ N_RB x NumOfSubcarrier x SCS + GuardBand x 2 ]
,where N_RB = Maximum Transmission Bandwidth in 38.101-1 Table 5.3.2-1,38.101-2 Table 5.3.2-1
NumberOfSubcarrier = 12 (constant)
SCS = Subcarrier Spacing = the number in the column labed as (A)
in 38.101-1 Table 5.3.2-1,38.101-2 Table 5.3.2-1
GuardBand = the number in the section (C) in 38.101-1 Table 5.3.3-1,38.101-2 Table 5.3.3-1
In case of CBW = 5Mhz, SCS = 30 Khz, meaning the second row in 38.101-1 Table 5.3.2-1
[ N_RB x NumOfSubcarrier x SCS ] = 11 x 12 x 30 = 3960 [kHz] ----- (a)
[ GuardBand x 2 ] = 505 x 2 = 1010 --------------------------------(b)
(a) + (b) = 3960 + 1010 = 4970 kHz = 4.970 Mhz which is close to 5 Mhz CBW
NOTE : Guardband is defined as 'Minimum' value in the table, so (a) + (b) may not be exactly same as CBW, but close enough to the CBW
< 38.101-1 Table 5.3.2-1: Maximum transmission bandwidth configuration NRB : FR1 >
< 38.101-2 Table 5.3.2-1: Maximum transmission bandwidth configuration NRB : FR2 >
< 38.101-1 Table 5.3.3-1: Minimum Guardband for each UE channel bandwidth and SCS (kHz) : FR1 >
< 38.101-2 Table 5.3.3-1: Minimum guardband for each UE channel bandwidth and SCS (kHz) : FR2 >
NOTE : This is for PDCCH/PDSCH/PUSCH. For SSB, refer to 38.104 - Table 184.108.40.206-1
< 38.101-1 v16.9 - Table 5.3.5-1 Channel Bandwidths for Each NR band : FR1 >
< 38.101-2 Table 5.3.5-1 Channel bandwidths for each NR band : FR2 >
Following tables shows the range and possible ARFCN values for each FR and band. Be careful when you sepcify ARFCN values for a specific bands because they are different not only in terms of ARFCN range, but also in terms of step size. It means that not all of ARFCN value within the range can be used for the band.
< 38.104 Table 220.127.116.11-1: NR-ARFCN parameters for the global frequency raster >
< 38.104 Table 18.104.22.168-1: Applicable NR-ARFCN per operating band in FR1 >
< 38.104 Table 22.214.171.124-2: Applicable NR-ARFCN per operating band in FR2 >
When I first saw the frequency specification called GSCN(Global Synchronization Raster Channel). I asked myself 'why we need this kind of additional frequency specification like this when we already have the existing frequency spec(raster) called ARFCN ?'.
I still don't know of the offical answers in 3GPP TS or TDocs (I failed to find the answers in the specification). So I just came up with my personal guess as follows :
When NR is activated in NSA, UE does not need to do blind search for SSB since the frequency, subcarrier spacing etc are all configured by LTE RRC Connection Reconfiguration message. But in SA, UE need to blindly detect SSB since UE need to detect this before it gets any RRC (MIB, SIB). If UE needs to search SSB based on ARFCN raster, it would take too long time since ARFCN raster is very narrow. So it would be good to define a SSB searching frequency in wider steps. This is the usage/purpose of GSCN.
As you see in 38.104 Table 126.96.36.199-1, ARFCN step is 5Khz or 15kHz or 60Khz depending on frequency range. If UE has to scan the spectrum in this granularity for cell search, it will take very long time to find a cell. In case of GSCN, as you see in the following table, the granularity is 50 or 150 or 250 Khz under 3Ghz and it has the granularity of 1.44 Mhz in above 3 Ghz frequency range and below 24.25Ghz, and the granuilirity jumps to 17.28 Mhz if the frequency goes over 24.25 Ghz. .
< 38.104 v15.7.0 - Table 188.8.131.52-1: GSCN parameters for the global frequency raster >
< 38.104 v16.9.0 - Table 184.108.40.206-1: Applicable SS raster entries per operating band (FR1) >
< 38.104 v15.4.0 - Table 220.127.116.11-2: Applicable SS raster entries per operating band (FR2) >