8.3.15 Downlink Power Control [FDD]
25.4233GPPRelease 17TSUTRAN Iur interface Radio Network Subsystem Application Part (RNSAP) signalling
8.3.15.1 General
The purpose of this procedure is to balance the DL transmission powers of one or more radio links for one UE.
This procedure shall use the signalling bearer connection for the relevant UE Context.
The Downlink Power Control procedure may be initiated by the SRNC at any time after establishing a Radio Link. If the SRNC has initiated in this DRNS the deletion of the last Radio Link for this UE context, the Downlink Power Control procedure shall not be initiated.
8.3.15.2 Successful Operation
Figure 25: Downlink Power Control procedure, Successful Operation
The Downlink Power Control procedure is initiated by the SRNC sending a DL POWER CONTROL REQUEST message to the DRNC.
The Power Adjustment Type IE defines the characteristic of the power adjustment.
If the value of the Power Adjustment Type IE is “Common”, the DRNS shall set the Power Balancing Adjustment Type of the UE Context set to “Common”. As long as the Power Balancing Adjustment Type of the UE Context is set to “Common”, the DRNS shall perform the power adjustment (see below) for all existing and future radio links for the UE Context and use a common DL reference power level.
If the value of the Power Adjustment Type IE is “Individual”, the DRNS shall set the Power Balancing Adjustment Type of the UE Context set to “Individual”. The DRNS shall perform the power adjustment (see below) for all radio links addressed in the message using the given DL Reference Power per RL. If the Power Balancing Adjustment Type of the UE Context was set to “Common” before this message was received, power balancing on all radio links not addressed by the DL POWER CONTROL REQUEST message shall remain to be executed in accordance with the existing power balancing parameters which are now considered RL individual parameters. Power balancing will not be started on future radio links without a specific request.
If the value of the Power Adjustment Type IE is “None”, the DRNS shall set the Power Balancing Adjustment Type of the UE Context set to “None” and the DRNS shall suspend on going power adjustments for all radio links for the UE Context.
If the Inner Loop DL PC Status IE is present and set to “Active”, the DRNS shall activate inner loop DL power control for all radio links for the UE Context. If the Inner Loop DL PC Status IE is present and set to “Inactive”, the DRNS shall deactivate inner loop DL power control for all radio links for the UE Context according to TS 25.214 [10].
Power Adjustment
The power balancing adjustment shall be superimposed on the inner loop power control adjustment (see TS 25.214 [10]) if activated. The power balancing adjustment shall be such that:
with an accuracy of ±0.5 dB
where the sum is performed over an adjustment period corresponding to a number of frames equal to the value of the Adjustment Period IE, Pref is the value of the DL Reference Power IE, PP-CPICH is the power used on the primary CPICH, Pinit is the code power of the last slot of the previous adjustment period and r is given by the Adjustment Ratio IE. If the last slot of the previous adjustment period is within a transmission gap due to compressed mode, Pinit shall be set to the same value as the code power of the slot just before the transmission gap.
The adjustment within one adjustment period shall in any case be performed with the constraints given by the Max Adjustment Step IE and the DL TX power range set by the DRNC.
The power adjustments shall be started at the first slot of a frame with CFN modulo the value of Adjustment Period IE equal to 0 and shall be repeated for every adjustment period and shall be restarted at the first slot of a frame with CFN=0, until a new DL POWER CONTROL REQUEST message is received or the RL is deleted.
8.3.15.3 Abnormal Conditions
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