The LTE Power Vs Time (PVT) measurement measures the time domain power dynamics of an LTE/LTE-A signal. This measurement is also known as Transmit ON-OFF Time Mask measurement. 3GPP specification limits the average OFF power that a user equipment (UE) can emit. The higher OFF power increases the rise over thermal noise (ROT) and causes interference to other users.

Measurement Overview

According to the 3GPP specification, if the carrier frequency is less than or equal to 3.0 GHz, the average OFF power of a UE must be less than or equal to -48.5 dBm. If the carrier frequency is more than 3.0 GHz and less than or equal to 4.2 GHz, the average OFF power of a UE must be less than or equal to -48.2 dBm.

The following image shows the various regions of the PVT measurement:



The LTE PVT measurement measures the power in the following segments:

OFF Power Before—This segment is defined as the OFF power region before the captured burst. The length is defined as 1 subframe for FDD and 10 SC-FDMA symbols for TDD signals.

ON Power—This segment is defined as the ON power region in the captured burst excluding the transient period of 20 µs at the beginning of the burst. The length of this region depends on the UL/DL configuration used for the transmission in case of TDD. The length of the captured burst is calculated by the measurement automatically.

OFF Power After—This segment is defined as the OFF power region of one sub-frame duration after the captured burst excluding the transient period of 20 µs at the beginning of the subframe.

The LTE PVT measurement is supported only with the triggered acquisitions: IQ Power Edge and Digital Edge Triggers. In case of Digital Edge Trigger, a marker is expected at the start of a frame.

LTE PVT Dynamic Range Mode

LTE UE transmits the maximum power of +23 dBm, the OFF power limit being -50 dBm, and the dynamic range required is around 73 dB. The theoretical OFF power limit can go even lower based on the thermal noise floor. For example, for 20 MHz bandwidth, the OFF power value is -96 dBm, for 10 MHz bandwidth, the OFF power value is -99 dBm, and so on. To measure this OFF power accurately, the dynamic range needed is very high (~120 dB) and none of the available instruments in the market provide this dynamic range. LTE PVT dynamic range mode provides a dual acquisition solution to achieve the required dynamic range.

The first acquisition captures the I/Q with the user defined reference level, which will measure the ON power accurately. However, OFF power will not be represented adequately due to the limited dynamic range of the device, which leads to an inaccurate measurement of OFF power. To solve this, a second acquisition is done at a lower reference level which ensures the OFF power regions are represented adequately. These two acquisitions are combined by the measurement to get a composite power trace having OFF region from the second acquisition and ON region from the first acquisition as shown in the picture below. The power measurement is done on this composite trace.

Supported Devices: PXIe-5644/5645/5646



LTE PVT OFF Power Exclusion Periods

The LTE PVT measurement supports the exclusion period on both sides of the burst that can be used to move OFF region boundaries.

RFmx LTE provides the OFF Power Exclusion Before property and OFF Power Exclusion After property, which allows you to configure/set a different exclusion period on each side of the burst. The following image shows the effect of configuring the exclusion period compared with 3GPP defined boundaries.

Note OFF region shrinks after the exclusion period is applied. The OFF region cannot be expanded because only positive values are supported.


The default value for both, the OFF Power Exclusion Before property and OFF Power Exclusion After property, is 0, which ensures the value adheres to the 3GPP definition. The maximum time value is limited to 100 µs on both the sides.