no problem, but watch the A interfaces from MSC to BSC, and the BSC processing capacity : the N7 will bring 2x more Paging messages to the BSC.
1 LAC for 1 BSC : only pagings for that LAC goes through A interface
2 LACs : twice more pagings must be carried by N7 and processed by BSC.
N7 : there is a “N7” TS on the A interface (BSC – MSC) that carries all the “N7” signalling 🙂
this signalling is used to carry call setup information (Authentication, Ciphering, Calls Numbers, Handover Messages, etc)
1 N7 Timeslot can take care of 120 calls.
The call itself (the TCH if you prefer) is carried by another A nterface timeslot, which is called the “CIC”)
I dont think there will be twice number of pagings, as the LAC size will be halved, so the MS present in each LAC will be almost halved assuming the 2 LAC areas are of same size. The bottomline is that the number of paging will be same in the whole BSC as the MS present will remain same.