Dynamic Power (DPOW) Measurement

Last updated: 2014-11-28

Dynamic Power (DPOW) Measurement Description

The Dynamic Power (DPOW) measurement measures a series of power levels for a step sequence. It provides a fast power calibration method that covers the typical 85dB (from -55dBm to +28dBm) dynamic range of a TD-SCDMA Mobile Station (MS).

The dynamic power measurement is not specified in the 3GPP standard.

The dynamic power measurement is not performed with a call established between the test set and MS. Rather, you must place your MS into a test mode which forces it to transmit a power sequence of successive steps. During the DPOW measurement, the power levels are measured in one timeslot with the step width being one subframe (5ms).

This measurement supports to specify up to 10 trigger steps as the start of the step sequence. Trigger steps are of the same constant level, and can be used to trigger the measurement when RF Rise is selected as the trigger source. After the trigger steps are the measurement steps whose power levels change monotonously. The figure below shows the relationship between the trigger steps and the measurement steps.

Relationship Between the Trigger Steps and the Measurement Steps

The DPOW measurement is not available in CW operating mode.
The Dynamic Power measurement can not be concurrent with other measurements. Hence starting the DPOW measurement will turn off any other measurement that is active, and vice versa.

This measurement requires the calibration data of the measurement receiver path gain, which are part of the results of the measurement calibration, see Calibrate Measurements.

Dynamic Power (DPOW) Measurement Parameters

RRC Filter: You may choose to measure the average power of each step with or without the RRC (Root Raised Cosine) filter in place.

GPIB Command: SETup:TDPower:FILTer[:RRC]

Trigger Source: see Trigger Source.

Please note that the trigger source setting only applies the first step, and the protocol trigger is used for the following steps.

Trigger Delay: see Trigger Delay.
Number of Power Steps: the number of steps in the measurement sequence.

GPIB Command: SETup:TDPower:NSTep:MEASure

Initial Step Power: the expected power for the initial measurement step.

GPIB Command: SETup:TDPower:INITial:POWer

Number of Trigger Steps: the number of steps in the trigger sequence. The trigger steps are important if your MS's first step power is too low to be triggered by RF Rise. See Relationship Between the Trigger Steps and the Measurement Steps.

GPIB Command: SETup:TDPower:NSTep:TRIGger

Synchronization Mode: specifies whether to use midamble synchronization for the dynamic power measurement.

GPIB Command: SETup:TDPower:SYNChronize:MODE

Measurement Timeout: see Measurement Timeout.

Dynamic Power (DPOW) Measurement Results

Integrity Indicator: see Integrity Indicator.
Trigger Step Power: the valid power results for the trigger steps are based on Number of Trigger Steps. See also FETCh:TDPower:STEP:POWer:TRIGger?.
Measurement Step Power: the valid power results for the measurement steps are based on Number of Power Steps. See also FETCh:TDPower:STEP:POWer[:MEASure]?.

The graphical above shows a typical measurement result, in which each step power is represented by a graphical "Bar". The x-axis graph represents the number of the measurement steps and the y-axis represents the power of the measurement step in units of dBm/1.28 MHz.

Input Signal Requirements

The trigger steps must be within 9 dB of the expected input level. For the measurement steps, the adjacent step difference is required to be between -20 to +9 dB.
The signal level into the test set's RF IN/OUT connector must be between -55 to +28 dBm, in a 1.28 MHz bandwidth.
For Non-HSDPA channel type, the frequency of the measured signal should be within 20KHz from the expected receiver frequency; For HSDPA channel type, the frequency of the measured signal should be within 2KHz from the expected receiver frequency.

Comparison with the Closed Loop Power Control Measurement

You can also use the Closed Loop Power Control (CLPC) measurement for dynamic power measurements on some special cases (see Taking Advantage of CLPC for Dynamic Power Measurement). A comparison is given below for dynamic power and closed loop power control measurement when measuring a step sequence.

Similarities with the CLPC measurement:

The step width is one subframe (5ms).
The measurement interval is one time slot excluding the guard period.
If the trigger source is Protocol or External, the measured time slot is TS1.
Concurrence with other measurements is not supported.

Differences from the CLPC measurement: