WCDMA PCCPCH: Primary Common Control Physical Channel Explained

This page describes the PCCPCH or Primary Common Control Physical Channel with respect to a WCDMA/UMTS system. The Primary CCPCH is a fixed-rate (30 kbps, SF=256) downlink physical channel used to carry the BCH transport channel.

The PCCPCH channel is a fundamental downlink physical channel used in WCDMA. It plays crucial role in broadcasting essential system information to all User Equipments (UEs) within a cell. This enables them to access and synchronize with the network.

Key characteristics of the PCCPCH

• Channel coding: CRC, convolutional code
• Symbol rate: 30 ksps
• Spreading factor: 256
• Modulation: QPSK
• Spreading: predefined code (Cch,256,1)
• Scrambling: Gold sequence - 3.84 Mcps, 10 ms periodic, primary scrambling code of the sector
• Power control: Not supported
• Pilot symbol: Included
• TFCI bits: Not included

Key Functions of P-CCPCH

1. Broadcasting System Information: Carries BCH transport channel which includes critical information such as cell identity, network parameters, and access restrictions. It helps UE to understand network configuration and its capabilities before initiating communication.​

2. Synchronization Assistance: Aligned with the P-SCH and S-SCH, P-CCPCH aids UEs to obtain time synchronization and frequency synchronization with the network.

3. Cell Identification: It uses predefined channelization code and scrambling code. P-CCPCH helps UEs identify and distinguish between different cells. This is very useful in overlapping coverage regions.​

4. Network Access Facilitation: With the help of system informations and synchronization details, P-CCPCH enables UEs to initiate access procedures, such as RRC connection establishment and PDP context activation.

Conclusion

The P-CCPCH is indispensable for the initial access and ongoing operation of UEs within a WCDMA network.