How Process Gain works in 3G?
Process Gain = 10 Log (Chip rate/Bit Rate)
  • Process gain differs for each service.
  • If the service bit rate is greater, the process gain is smaller, UE needs more power for this service, then the coverage of this service will be smaller, vice versa.

For common services, the bit rate of voice call is 12.2kbps, the bit rate of video phone is 64kbps, and the highest packet service bit rate is 384kbps(R99). After the spreading, the chip rate of different service all become 3.84Mcps.