Spectrum Emission Mask Measurement Description

Last updated: January 19, 2009

How is the Spectrum Emission Mask Measurement Made?

What is the Spectrum Emission Mask?

The UE conformance specifications in 3GPP TS 34.121, Section 5.9 and 5.9A define a mask for out of channel emissions. This mask is defined relative to the in-channel power. The graphic below is an example of out-of-channel measurement results you might see on the test set. The spectrum emission mask for each of the four frequency bands is visible in green.

In-channel power

The in-channel power is measured on the RF input signal which is filtered with a 3.84 MHz bandwidth Root-Raised Cosine (RRC) filter with a rolloff of alpha = 0.22. The measurement interval for the in-channel power is 1 timeslot (666.7 us).

Out-of-channel emissions

The out-of-channel emissions found in frequencies between 2.5 and 12.5 MHz away from the center channel frequency are determined in four symmetrical bands on each side of the carrier.

The emissions are measured with either a 30 kHz or 1 MHz bandwidth Gaussian measurement filter. The spectrum emission mask measurement's pass/fail limits for the 30 kHz bandwidth filter and 1 MHz bandwidth filter are settable. See Spectrum Emission Mask in the Test Set for details of the spectrum emission mask measurement in the test set.

Spectrum Emission Mask in the Test Set
	Frequency Offset from carrier	Measurement Bandwidth	Resolution Bandwidth (RBW)
Range 1	2.5 - 3.5 MHz	30 kHz	10 kHz
Range 2	3.5 - 7.5 MHz	1 MHz	250 kHz
Range 3	7.5 - 8.5 MHz	1 MHz	250 kHz
Range 4	8.5 - 12.5 MHz	1 MHz	250 kHz

NOTE

The resolution bandwidth (RBW) may also be referred to as the measurement step size.

The compliance of Range 1 with the specified mask is determined using the following measurement procedure. A 30 kHz Gaussian measurement filter is centered 2.515 MHz away from the carrier frequency on both sides. The filter is shifted by 10 kHz for each measurement until the 30 kHz filter is centered at a 3.485 MHz offset from the carrier. This provides 98 measurement points on each side of the carrier for evaluating mask compliance.

The remaining frequency ranges are evaluated in the same manner. However, a 1 MHz Gaussian measurement filter is used and the resolution bandwidth is 250 kHz instead of 10 kHz. The measurements begin with the filter centered at 4 MHz and end with it centered at 12 MHz. This provides 33 unique measurement points on each side of the carrier for evaluating mask compliance. However, there are redundant points at 7.5 MHz and 8.5 MHz. Therefore, 35 measurement points are available when measurement results are queried via GPIB, while 33 points are visible on the test set's spectrum emission mask measurement graphic.

Additional Spectrum Emission Mask Requirements

According to 3GPP TS 25.101 (v8.3.0, 2008-07), for operation in Band II, IV, V, X, XII, XIII and XIV, the out-of-channel UE emissions should satisfy both the basic requirements and the additional requirements, which are specified by the absolute power within the measurement bandwidth. For additional SEM requirements, there are 2 symmetrical ranges on each side of the carrier. These ranges are measured in a 30 kHz, 100kHz or 1 MHz bandwidth. The different bands have different range definitions (see Additional Spectrum Emission Limits for Band II, IV, X , Additional Spectrum Emission Limits for Band V , and Additional Spectrum Emission Limits for Band XII, XIII, XIV

To use the additional Spectrum Emission Mask requirements results, you must calibrate this measurement using theCalibrate Measurements procedure (see Calibrating the Test Set ).

Additional Spectrum Emission Limits for Band II, IV, X
	Frequency Offset from carrier	Measurement Bandwidth	Minimum Requirement
Additional Range 1	2.5 - 3.5 MHz	30 kHz	-15 dBm
Additional Range 2	3.5 - 12.5 MHz	1 MHz	-13 dBm

Additional Spectrum Emission Limits for Band V
	Frequency Offset from carrier	Measurement Bandwidth	Minimum Requirement
Additional Range 1	2.5 - 3.5 MHz	30 kHz	-15 dBm
Additional Range 2	3.5 - 12.5 MHz	100 kHz	-13 dBm

Additional Spectrum Emission Limits for Band XII, XIII, XIV
	Frequency Offset from carrier	Measurement Bandwidth	Minimum Requirement
Additional Range 1	2.5 - 2.6 MHz	30 kHz	-13 dBm
Additional Range 2	2.6 - 12.5 MHz	100 kHz	-13 dBm

Spectrum Emission Mask Measurement Parameters

Multi-Measurement Count: (see Statistical Measurement Results ).
Trigger Arm: (see Trigger Arm (Single or Continuous) Description ).
Trigger Source
You must specify how you want to trigger the measurement using theTrigger Source setting.

You may setTrigger Source to the following: (for more information on these trigger types, see Trigger Source Description ).
- Auto: if the UE is synchronized to the test set, it uses protocol triggering; otherwise, it uses immediate triggering.
- External
- HS-DPCCH:
  This setting is only applicable to the lab application or a feature-licensed test application.
  
  WhenTrigger Source is set toHS-DPCCH , you can specify on which uplink subframe the measurement triggers using the HS-DPCCH Trigger Subframe Alignment setting.
  
  Trigger Source can only be set to HS-DPCCH when Channel Type =12.2k RMC + HSDPA or12.2k RMC + HSPA .
- Immediate
- Protocol: Derived from the 10 ms downlink DPCH frame clock.
Trigger Delay
You can move the start point of the in-channel and out-of-channel measurement intervals relative to the trigger using the Trigger Delay setting.
HS-DPCCH Trigger Subframe Alignment
This setting is only applicable to the lab application or a feature-licensed test application.

When Trigger Source is set toHS-DPCCH , you can specify on which uplink subframe the measurement triggers. You can then use the Trigger Delay setting to move the measurement interval relative to that subframe boundary.
Fail Limit Mask
You can select whether SEM is tested for the Basic Limit Only or Basic and Additional Limits:
- Basic: Results are returned only for ranges 1 to 4 of the basic limit
- Basic and Additional Limit: Results are returned for range 1 to 4 and the additional range 1 to 2.
Measurement Timeout: (see Measurement Timeouts ).
Limit 30 kHz Bandwidth: +-2.5 MHz
Limit 30 kHz Bandwidth: +-3.5 MHz
Limit 1 MHz Bandwidth: +-3.5 MHz
Limit 1 MHz Bandwidth: +-7.5 MHz
Limit 1 MHz Bandwidth: +-8.5 MHz
Limit 1 MHz Bandwidth: +-12.5 MHz

Spectrum Emission Mask Measurement Results

Pass/Fail for the overall spectrum emission mask. If any out-of-channel frequency range does not comply with the standard, the entire mask fails.
In-channel power
Pass/Fail for each of the four individual frequency ranges (plus pass/fail for the two additional frequency ranges if testing for the additional requirements).
Power level vectors relative to in-channel power for each frequency range. These vectors contain the power measured at each frequency offset in the individual ranges. The value of each frequency offset is determined by the starting measurement position and the resolution bandwidth. For example, range 3 (7.5 MHz to 8.5 MHz) starts at 7.5 MHz and has a resolution bandwidth of 250 kHz. Therefore, relative power measurements are returned for offsets 7.5, 7.75, 8, 8.25, and 8.5 MHz from the carrier frequency.
Results for each frequency range. The relative power level and the frequency offset of the largest mask error, the margin of that error, and whether or not the range passed or failed the spectrum emission mask specifications are the available results.

Spectrum Emission Mask Input Signal Requirements

For this measurement the test set's receiver uses autoranging to adjust for the level of the signal being measured; therefore the expected signal level does not need to be specified during measurement setup.
The frequency of the signal being measured must be in the range of 800 MHz to 1000 MHz, 1700 MHz to 1990 MHz, or 2480 to 2580 MHz.
The level into the test set's RF IN/OUT connector must be in the range of +5 dBm to +28 dBm, in a 3.84 MHz bandwidth.
The uplink must be of constant in-channel power for the duration of this measurement. This requirement has implications for correct power control configuration, and uplink dynamics in HSDPA and HSUPA.

Spectrum Emission Mask Measurement Calibration

You must calibrate this measurement using theCalibrate Measurements procedure (see Calibrating the Test Set ).