For MIMO 2x2 I need to use MOD3, and for MIMO4x4, MOD6.
Is it true?
Yes, to avoid RS-RS collision.
Don’t think that 4T4R also MOD3 and MOD6 for 1T1R?
True, 4T4R doesn’t required to be MOD6.
MOD3 works well.
I thinks same
Mod6 for 1T1R,
And for 4T4T , Mod3 is ok
CRS port red-color in frequency-domain (sub-carrier) position is decided by PCI mod 3.
To avoid 3 sector of a site conflict RS in frequency domain: 2T2R should avoid PCI mod 3, 4T4R also just need PCI mod 3 is ok while 1T1R need PCI mod 6.
In 5G with DMRS enabled need PCI mod 4.
5G, PCI MOD 4 rule is to avoid conflict of PBCH DMRS.
Yes, only if you are using DMRS, otherwise you can use PCI mod3.
Mode 3/6 is related with PCI with respect of sector not with MIMO