# In F1 Range below 6 GHz, how to know if L is 4 or 8 bit for case A, B and C?

Hello Everyone.
As you are working on F1 Range below 6 GHz, how would you know that L is 4 or 8 bit for case A, B and C?
For example, L is 4 bits with 51 Resource Block and SCS 30kHz, so this set 20 MHz from 3GPP F1 Range Table.
The question is how do you know the carrier frequecy in that case.
I think it is below 3 GHz, so you used L is 4 bits.
How do you know that is below 3 GHz?
(This is for SSB for sync).

Which table are you referring? Control resource set part of spcell config common under sib1.

The table for F1 Range.
That has SCS, BW and Resourse Block.
I know that F2 should be 64 bit rather that 4 or 8 bit for L SSB.
Is that what you mean?

We have mapping like short, medium, long bit as per Freq config.

Yes, right.
How do you know when will you set short, medium, long bit for carrier config?
I am simulating this in MATLAB.
F1 Range I don’t know when shall I use Lssb length, 4 or 8.

• Short for f < 3 GHz
• Medium for f > 3 < 6 GHz
• Long for f > 6 GHz

FR1 use medium.

But I don’t know carrier freq.
How shall I know carrier freq?

Is it for all BWs cases?

That depend upon your BW, for deriving NRRFCN.

I am using the F1 Range table.

Any particular band?

With medium Lssb so, I shall use then 8 bits.
This how works in Rel.15 with Lssb 8 bit for F1 Range then?
If that so, I will simulate it with this length.

One last question please: transmission periodicity?

20 miliseconds.

This values of transmission periodicity can be select in any case?
Or only we use 20 ms for F1 Range?

It go upto 160 ms, but mostly 20 ms used. I.e. ssb periodicity as of now.

Ok, but when do we use other values?
Depends on the requirements for 3GPP or Customer/Project?
UE can assume a default periodicity of 20ms during initial cell search or idle mode mobility?
So if this can be default, then it is how would be.

Thanks @ankgitm for all your good help.

L =4 for f < 3 GHz
L = 8 for 3 GHz < f < 6 GHz

One exception about 2.4 GHz for TDD, if I remember correctly.

In that case, how should I know the carrier freq?

Yes, you are right.