Thank you for your reply but there is a problem in this,
actually in uplink different users at BS are separated by scrambling code and in downlink different users are separated by channelization code.
in downlink , channelisation codes are used to distinguish different channels from same basestation ,while scrambling codes distinguish different basestations
in uplink , scrambling codes distinguish different users (mobiles) while channelization codes distinguish different channels from same mobile (like video call , data , and control at the same time from same mobile station )