I- and Q-branches as a complex-valued stream of chips. Then the complex-valued scrambling code Sr-msg,n scrambles this complex-valued signal. The 10 ms scrambling code applica- tion aligns with the 10 ms message part radio frames, i.e. the first scrambling chip cor- responds to the beginning of a message part radio frame [8]. PRACH message data part Sr-msg,n PRACH message control part Figure 4.10 Spreading of PRACH message part. 4.3.3.3.2 PCPCH As in the PRACH, the PCPCH preamble part consists of a complex-valued code, and the PCPCH message part includes data and control parts, Figure 4.11 illustrates its spreading principle. PCPCH message data part Sc-msg,n PCPCH message control part Figure 4.11 Spreading of PCPCH message part. In the message part, real-value sequences represent the binary control and data parts, i.e. the binary value '0' maps to the real value +1, while the binary value '1' maps to the The UMTS Network and Radio Access Technology real value -1. The channelization code CC spreads the control part, while channelization code cd spreads the data part. Channelization and weighting follows the same pattern as in the PRACH. 4.3.4 Uplink Channelization Codes The Orthogonal Variable Spreading Factor (OVSF) channelization codes preserve or- thogonality between a user's different physical channels. A tree illustrated in Figure 4.12 defines these codes. C ch,2,0 = (1,1) Coh.4.0 ((1,1,1,1) Coh.4,1=(1,1,-1,-1) C ch,1,0 = (1) Cch,2,1==1,-1) Coh.4.= (1,-1,1,-1) Coh.4.3==(1,-1,-1,1) Figure 4.12 Orthogonal Variable Spreading Factor (OVSF) code-tree generation. The channelization codes in the OVSF tree have a unique description as Cch,SF,k where SF is the spreading factor of the code and k is the code number, 0 < k SF - 1. Each level in the code tree defines channelization codes of length SF, corresponding to a spreading factor of SF. From [8] the generation method for the channelization code is defined as: Cch.1.0 =1, (4.1) (4.2) C oh2(n+1), Coh.2".0 C ch.2".0 C oh2(n+1), C oh.2". Coh2(n+1)2 C oh 2" Coh2(a+1)3 (