Last updated: October 19, 2012
This section is only applicable to the lab application.
The test set supports downlink closed power control if a RB test mode call connection is set up. In response to the TPC (transmit power control) bits from the UE, the test set adjusts the downlink DPCCH/DPDCH/F-DPCH power accordingly. Downlink power control helps to test the ability of the UE receiver to converge to required link quality set by the network while using as low power as possible in downlink.
For an ordinary transmit power control procedure, the UE generates TPC commands, and sends a unique TPC command in each slot to control the network transmit power (referred to as downlink power control mode 0 (DPC_MODE = 0) in the 3GPP standard). The DPC_MODE parameter is a UE specific parameter and fixed to "0" in the test set, see Operating Considerations .
Another situation of downlink power control is power control in compressed mode, see Compressed Mode .
When Downlink
Power Control Parms ( F1 ) is pressed,
the following parameters are displayed in the Downlink
Power Control Parameters middle menu:
Downlink
Power Control State
This parameter allows you to enable or disable downlink power control when a RB test mode call is established.
This setting is not available when MIMO is active.
This parameter
can only be set when the Call
Status is Idle
.
GPIB Command: CALL[:CELL]:CLPControl:DOWNlink[:STATe] .
WCDMA Maximum DPCH Level
This parameter sets the relative power level to the Cell 1 Connected CPICH Level .
GPIB Command: CALL[:CELL]:CLPControl:DOWNlink:DPCHannel:LEVel:MAXimum[:WCDMa]
HSDPA Maximum (F-)DPCH Level
HSDPA
Maximum (F-)DPCH Level sets the relative power level
to the HSDPA Cell 1 Connected CPICH Level
.
GPIB Command: CALL[:CELL]:CLPControl:DOWNlink:DPCHannel:LEVel:MAXimum:HSDPa
HSPA Maximum (F-)DPCH Level
HSPA
Maximum (F-)DPCH Level sets the relative power level
to the HSPA Cell 1 Connected CPICH Level
.
GPIB Command: CALL[:CELL]:CLPControl:DOWNlink:DPCHannel:LEVel:MAXimum:HSPA
Minimum (F-)DPCH Level
The average
power of transmitted DPCH symbols over one time slot should
not exceed Maximum DPCH Level, nor should it be below the
Minimum (F-)DPCH Level
.
GPIB Command: CALL[:CELL]:CLPControl:DOWNlink:DPCHannel:LEVel:MINimum
Target Quality on DTCH
This parameter specifies the quality target (BLER target) on DTCH. When Downlink Power Control State is set to On, this information is sent to the UE via the RadioBearerSetup message.
This parameter can only be set when the call status is idle.
GPIB Command: CALL[:CELL]:CLPControl:DOWNlink:DTCHannel:TARGet[:QUALity]
Target Quality on DCCH State
This parameter specifies whether the BLER target is to be assigned to a DCCH. If it is set to On, the BLER target is to be assigned to a DCCH and the outer loop is based on DTCH rather than DCCH. If it is set to Off, the outer loop is based on DCCH.
This parameter can only be set when the call status is idle.
GPIB Command: CALL[:CELL]:CLPControl:DOWNlink:DCCHannel[:STATe]
Target Quality on DCCH
When the
Target
Quality on DCCH State is set to On
, Target Quality on DCCH specifies the BLER target on DCCH.
This parameter can only be set when the call status is idle.
GPIB Command: CALL[:CELL]:CLPControl:DOWNlink:DCCHannel:TARGet[:QUALity]
The Downlink
Power Control Parameters window displays the Downlink
Power Control State and the Current
Maximum (F-)DPCH Level that is being used by the test set.
You can also query these results by:
| Result | GPIB Command |
|---|---|
Downlink
Power Control State |
CALL[:CELL]:CLPControl:DOWNlink[:STATe] |
Current
Maximum (F-)DPCH Level |
CALL:STATus:CLPControl:DOWNlink:DPCHannel:LEVel:MAXimum? |
When DPCH
Ec/Ior Parameters ( F2 ) is pressed,
the following parameters are displayed in the DPCH
Ec/Ior Parameters middle menu:
DPCH
Ec/Ior Count
This setting
allows you to specify how many realtime downlink power control
information to be recorded each time the Start
Recording DPCH Ec/Ior action is performed.
GPIB Command: CALL[:CELL]:CLPControl:DOWNlink:ECIor:RECord:COUNt
DPCH Ec/Ior Threshold
By setting this parameter, the test set can calculate and display how many DPCH_Ec/Ior is below the threshold (Ratio of DPCH Ec/Ior Bellow Threshold) during the realtime recording period.
GPIB Command: CALL[:CELL]:CLPControl:DOWNlink:ECIor:THReshold
See the table below on how to query the DPCH Ec/Ior results:
| CALL:STATus:CLPControl:DOWNlink:ECIor:RECord:COUNt? | |
| Ratio of DPCH Ec/Ior Below Threshold | |
| Maximum DPCH Ec/Ior | |
By pressing the
Start Recording DPCH Ec/Ior
, the test set keeps a realtime track of the following DPCH Ec/Ior
information during the downlink power control: Count
of DPCH_Ec/Ior Gathered , Ratio
of DPCH_Ec/Ior Bellow Threshold and Average/Maximum/Minimum
DPCH_Ec/Ior . The number of the downlink power control
information to record is specified by DPCH
Ec/Ior Count . Stop Recording
DPCH Ec/Ior action will abort the recording. Recording
State on the Recorded DPCH
Ec/Ior Statistic Info screen shows whether the recording
is in process or Idle.
Any of the following operations will reset the realtime DPCH Ec/Ior statistic information:
GPIB Command: CALL[:CELL]:CLPControl:DOWNlink:ECIor:RECord:STARt and CALL[:CELL]:CLPControl:DOWNlink:ECIor:RECord:STOP
On
, the Maximum DPCH Level must not be less than the Connected
DPCH Level (Note: the Maximum DPCH Level setting for WCDMA/HSDPA/HSPA
only specifies the relative value to Connected CPICH Level,
remember to add them together before comparing to the Connected
DPCH Level. See also Cell 1 Connected DPCH
Level , HSDPA Cell 1 Connected DPCH Level
or HSPA
Cell 1 Connected DPCH Level ). Likewise, when the Downlink Power Control State is Off
, if the Maximum DPCH Level is not configured correctly, the
Downlink
Power Control State is not allowed to be set back to On.RB
test Mode , the Channel Type is set to 12.2k
RMC and the 0k and 12.2k RMC state (
CALL[:CELL]:CLPControl:DOWNlink:RMC012:STATe ) is On.