How to derive new preamble formats in release 38.211?

[jayachandra_Reddy]

Hello eveyone.

In new release of 38.211 we can see preamble formats have been introduced 139 & 1151 & 571.

Any idea how to derive these values?

Like long format we have 839 sequences 6 RB fixed for format 0 and 1 and 2 and SCS is 1.25 for RACH format and 6RB * 12 RE = 72 REs * 1.25 SCS = 869 and out of 864-(25 Guard tones).

So total the value derive is 839 unique sequences.

But in short format how these 571 and 1151 derive?