Sorry
I've missed your comment "CDMAOne"
Each link(forward, reverse) of IS-95 has different codes structure.
in forward link, Walsh codes x long PN are used as spreading codes.
Walsh codes are used for discrimination channel.
long pn-codes are used for randomization and discrimination base station.
channel interference in same cell(except overreach) is vanished completely.
in reverse link, M-array x short PN are used as spreading codes.
but
channel interference remains in this channel.