Terminology » WLAN » WCDMA CSICH: CPCH Status Indication Channel Explained

WCDMA CSICH: CPCH Status Indication Channel Explained

wcdma umts csich channel cpch

The CSICH (CPCH Status Indicator Channel) is a downlink physical channel used in the WCDMA system specifically for CPCH (Common Packet Channel) operations.

The CPCH Status Indicator Channel (CSICH) is a fixed rate (SF=256) physical channel used to carry CPCH status information.

WCDMA CSICH

Function of WCDMA CSICH

  • CSICH broadcasts the availability status of one or more CPCHs to the User Equipments (UEs).
  • It tells UEs whether a particular CPCH is idle or busy (i.e. occupied by another UE).
  • Based on this status, a UE decides whether it can initiate transmission on that CPCH or needs to wait or choose another channel.

Summary

CSICH helps UEs in WCDMA networks to know whether a CPCH is available for transmission or currently busy, improving the efficiency and success rate of contention based access.