CCCH-CONF Value tells,Whether you are using COMBINED or NON-COMBINED Configuration.
I dont remember exactly, What exactly CCCH_CONFIG=0 stands for.
First lets Consider COMBINED config
COMBINED : Total CCCH = 9
BS_AG_BLK_RES=1
So Channels reserved for Pagig = 9-1 = 8
BS_PA_MFRMS=4 : This tells After how many multiframes paging group repeats.
So total Paging groups = 8*4 = 32
Lets IMSI Value = x
Paging Group for a particular Mobile =
(x MOD 1000) MOD 32 where 32 is total Paging Groups.
e.g. if IMSI = 404685505601234
Paging Group = (404685505601234 MOD 1000)MOD32
i.e. => 234 MOD 32 => 10
Paging Group = 10.
NON-COMBINED:
Total CCCH = 3
BS_AG_BLK_RES=1
So Channels reserved for Pagig = 3-1 = 2
BS_PA_MFRMS=4
So total Paging groups = 2*4 = 8
Paging Group = (IMSI MOD 1000)MOD 8
e.g
404685505601234 MOD 1000 MOD 8
=> 234 MOD 8 = 2
Paging Group = 2
I hope this answers your query