EDGE Dynamic Power (EDP) Measurement

EDGE Dynamic Power (EDP) Measurement

Last updated: December 3, 2008

The EDP measurement is an enhancement to the Dynamic Power measurement. The EDP measurement tests GMSK and 8PSK bursts while in EGPRS test modes in addition to testing only GMSK modulated signals. Set up parameters and measurement results for this measurement are only accessible using the GPIB interface. This measurement is only available in test mode. See Operating Considerations for more details.

How is an EDGE Dynamic Power Measurement Made?

Mobile stations that support EDGE maintain GMSK, the modulation scheme used for GSM and GPRS, for low data rates. EDGE also supports 8PSK, a modulation scheme that extends the raw data rates of GMSK. The test set's EDP measurement provides a mechanism to quickly obtain power measurements of either 8PSK or GMSK modulated signals from a mobile station.

For GMSK modulated bursts generated from an EDGE mobile station, burst power is the only measurement method available in the test set. Burst power determines the power of the burst without any compensation for data content. For 8PSK modulated bursts generated from an EDGE mobile station, the test set offers the following measurement methods: burst power, variable Estimated Carrier Power (ECP), or fixed ECP. ECP is an approximation of the long-term average burst power. Variable ECP assumes a random data pattern is used for each burst and so determines an estimated carrier power compensation factor for each burst in the ramp segment individually. To use the fixed ECP to determine each burst power all bursts in the ramp segment must contain the same data pattern. This results in a faster measurement time because it is only necessary to determine the estimated carrier power compensation factor for the highest power burst in the ramp, which is then applied to each burst in the ramp segment. Variable ECP or Fixed ECP values for each burst in a ramp segment are determined by a single burst. For multi-segment ramps, the same measurement method is used for all segments. Multi-segment ramps are concatenations of single segment ramps, see Figure 1 .

The EDGE Dynamic Power (EDP) measurement must range the measurement receiver individually for each burst in a ramp segment. The receiver's expected power level for the first burst in a ramp segment can be either manually specified or can use the test set's expected power setting. The expected power level for subsequent group bursts are determined by adding the step size, or Expected Maximum Difference (EMD), to the measured power of the final burst in the previous burst group. Figure 1 illustrates how the EMD is used to find all subsequent group burst power levels after the first group. The EMD parameter may be a positive or negative value to facilitate increasing or decreasing power ramps, and can be set separately for each segment in a multi-segment ramp.

When the Initial Power State parameter is set to 1 or ON, the same expected power setting is used for the first burst in all ramp segments. The value used for the initial power depends on the state of the Expected Power Control. If the Expected Power Control parameter is set to Auto, the MS TX Level Burst 1 power level is used. If the Expected Power Control parameter is set to Manual, the expected power that is used is the power level setting for burst 1 that the test set's receiver is expecting to see. When the initial power state is set to OFF, the initial power values for each ramp segment can be set with the Initial Power Value parameter. For more information on the Initial Power State parameter see SETup:EDPower:INITial:POWer:AUTO .

Figure 1

Series of mobile station generated bursts at consecutive power levels.

The bursts drawn with solid lines of Figure 1 depicts what a typical single power ramp segment looks like. The dashed lines are portions of other segments of the multi-segment power ramp. Figure 1 is a single ramp segment with a burst count of 15 and a group count of 5. The number of segments measured in a multi-segment power ramp are configured with the Ramp Segment Count parameter. The test set measures the number of bursts in a ramp segment given by the Ramp Segment Burst Count parameter.The number of bursts at each expected power level is configured with the Ramp Segment Group Count parameter.

EDP measurement results are returned in blocks, or ranges, of 100 values. For example, if the burst count is 150, range 1 will return 100 power measurement results, range 2 will return 50 power measurement results, and ranges 3-10 will return a NaN because there are no result in the range. The same number of integrity values are returned as the burst power measurements. Range 1 will contain 100 integrity values and power measurements, range 2 will contain 50 integrity values and power measurements, and ranges 3-10 will contain the value 1, indicating no results are available for the specified range.

EDGE Dynamic Power Measurement Configurable Parameters

Parameter GPIB Command
Trigger Arm INITiate:<measurement mnemonic>[:ON] using EDPower as the <measurement mnemonic>
Timeout State and Time SETup:EDPower:TIMeout[:STIMe] SETup:EDPower:TIMeout:TIME SETup:EDPower:TIMeout:STATe

Expected Maximum Time Interval State and Value

SETup:EDPower:EMTInterval[:STIMe] SETup:EDPower:EMTInterval:STATe SETup:EDPower:EMTInterval:TIME

Ramp Segment Burst Count SETup:EDPower:COUNt:NUMBer
Ramp Segment Group Count SETup:EDPower:COUNt:GROup:SIZE
Ramp Segment Expected Maximum Difference SETup:EDPower:EMDifference
Ramp Segment Initial Power SETup:EDPower:INITial:POWer
Ramp Segment Initial Power State SETup:EDPower:INITial:POWer:AUTO
Ramp Segment Count SETup:EDPower:COUNt:RSEGment

Measurement Method


Input Signal Required

The input signal for the EDGE Dynamic Power measurement must be a normal burst.

The EDGE Dynamic Power measurement completes and meets its measurement accuracy specifications when the signal meets the following input signal conditions.

EDGE Dynamic Power Measurement Results

The EDGE Dynamic Power measurement does not use the multi-measurement state parameter, and so does not return minimum, maximum, and standard deviation values. Instead, specify the number of bursts to measure using the Ramp Segment Burst Count parameter (see SETup:EDPower:COUNt:NUMBer ). A single measurement returns the integrity indicator and power level for every burst measured. For example, if you set the number of bursts to 15, the returned comma-separated list contains 15 integrity values followed by 15 corresponding measurement values.

Trigger Source

The trigger source that EDGE Dynamic Power measurement supports is RF Rise.

Operating Considerations

Related Topics

Programming an EDGE Dynamic Power Measurement



Test Adherence to Standards