3G load sharing

3G / 2G
1

Dears

I have 3 carriers in 3G
F1 U900
F2 2100
F3 2100
I will set F1 with spg and DRD parameters CS and PS
And F2 and f3 set PS only
After check still have CS in f2 and f3 and
CS RAB success rate is very low