In the scrambling process the code sequence is multiplied with a pseudorandom scrambling code. • The scrambling code can be a long code (a Gold code with 10 ms period) or a short code (S(2) code). • In the downlink scrambling codes are used to reduce the inter-basestation interference. Typically, each Node B has only one scrambling code for UEs to separate base stations. Since a code tree under one scrambling code is used by all users in its cell, proper code management is needed. • In the uplink scrambling codes are used to separate the terminals.
