▁given ▁T ET RA ▁radio ▁cell ▁becomes ▁us able . ▁A ▁neighbour ▁cell ▁becomes ▁radio ▁us able ▁when ▁the ▁cell ▁has ▁a ▁down link ▁radio ▁connection ▁of ▁sufficient ▁quality . ▁ ▁The ▁following ▁conditions ▁must ▁be ▁met ▁in ▁order ▁to ▁declare ▁a ▁neighbour ▁cell ▁radio ▁us able : ▁The ▁neighbour ▁cell ▁has ▁a ▁path ▁loss ▁parameter ▁C 1 ▁or ▁C 2 ▁that ▁is , ▁for ▁a ▁period ▁of ▁ 5 ▁seconds , ▁greater ▁than ▁the ▁fast ▁res elect ▁threshold ▁plus ▁the ▁fast ▁res elect ▁threshold , ▁and ▁the ▁service ▁level ▁provided ▁by ▁the ▁neighbour ▁cell ▁is ▁higher ▁than ▁that ▁of ▁the ▁serving ▁cell . ▁No ▁successful ▁cell ▁res e lection ▁shall ▁have ▁taken ▁place ▁within ▁the ▁previous ▁ 1 5 ▁seconds ▁unless ▁MM ▁requests ▁a ▁cell ▁res e lection . ▁The ▁MS - M LE ▁shall ▁check ▁the ▁criter ion ▁for ▁serving ▁cell ▁rel in qu ishment ▁as ▁often ▁as ▁one ▁neighbour ▁cell ▁is ▁sc anned ▁or ▁monitor ed . ▁ ▁The ▁following ▁conditions ▁will ▁cause ▁the ▁MS ▁to ▁rate ▁the ▁neighbour ▁cell ▁to ▁have ▁higher ▁service ▁level ▁than ▁the ▁current ▁serving ▁cell : ▁ ▁The ▁MS ▁subscri ber ▁class ▁is ▁supported ▁on ▁the ▁neighbour ▁cell ▁but ▁not ▁on ▁the ▁serving ▁cell . ▁ ▁The ▁neighbour ▁cell ▁is ▁a ▁priority ▁cell ▁and ▁the ▁serving ▁cell ▁is ▁not . ▁ ▁The ▁neighbour ▁cell ▁supports ▁a ▁service ▁( that ▁is , ▁T ET RA ▁standard ▁speech , ▁packet ▁data , ▁or ▁encryption ) ▁that ▁is ▁not ▁supported ▁by ▁the ▁serving ▁cell ▁and ▁the ▁MS ▁requires