we need 1 BCCH for a sector and as for as singanalling is concern u need to calculate it.
for a 444 site we take 2 TS per sector for signalling,
it depends for on much ur signalling load is like
(no. of call attempts*avg SDCCH holhing time)/ 3600 + (no. of LU * avg Sdcch holding time)/3600.
n da no. of erlang u get.. look for no of channel required on Erlang table.
that will gve u no. of channel for signalling