tanuj / woth5,
if you define a lot of neighbours, the MS have to scan ALL of them, in order to detect the 6 best neighbours.
But it doesn’t drain the battery : the “periodicity” of the measurements is the same, but each frequency is measured less often.
So the real drawback is that the neighbours are not updated as quickly as before (when there is less neighbours). But really, it’s not such a big issue at all !
Main impact is on the frequency planning : neighbours should not use co-channel or adjacent channels. When you define two cells as neighbours, you are putting constraints on the possible frequencies you could use.