WCDMA - Power Control

Power Control:

We know all users are in same frequency at same time soPower control is used to controlled the level of the transmitting power in order to minimize interference,improve quality of connection, reducing of NEAR-FAR effects and increase capacity of system.

There are three type of power control

Open loop power control

Inner loop Closed loop power control

Outer loop closed loop power control

Open loop power control:

                                      The UE determine an estimation of the downlink path-loss between thee base station and the UE by the measuring of UTRA carrier received signal strength at the mobile through the medium of the SI message on the P-CCPCH. 

Outer loop closed loop power control:

                                             It is used to compare the received BLER (Block error rate) and target the BLER.

Inner loop Closed loop power control:

                                   It is used to compare the received SIR (Signal to interference ratio) and target the SIR

Power control Parameter:

Primary CPICH Power:                                      Power to be used for transmitting the PCPICH.

BCH Power:    BCH power is the power to be used for transmitting on the BCH, relative to the primary CPICH Power value.

Primary SCH Power:

Secondary SCH Power:

AICH Power:     AICH power to be used for transmitting on AICH, relative to the primary CPICH Power value.

The value range is set in a short term to cover both the RRC and NBAP spec.