Measurement Speed Considerations (LTE)
The primary factor that affects measurement speed is the amount of input data being processed. For example, when only a single slot is of interest (Measurement Interval is set to 1 slot), then decreasing the Result Length to one slot will speed up the measurement since less data needs to be captured and processed by the demodulator.
If you use a frame start signal as an external trigger to your measurement hardware, then you can decrease the amount of captured data by changing the Analysis Start Boundary parameter from to for uplink or for downlink because the first slot found will be the beginning of the frame. This can make the measurement faster because there is less data to acquire, and less data to perform a sync search on. See Result Length for more information.
Depending on the video card installed in your computer, another important factor in measurement speed may be the use of traces that contain a large number of points, such as IQ Meas, Error Vector Spectrum, or Error Vector Time. Changing these traces to simpler traces like RMS Error Vector Spectrum or RB Error Magnitude Spectrum can significantly improve measurement speed.
When controlling the LTE Long Term Evolution demodulator from the .NET API 1) Access Preamble Indicator, or 2) Application Programming Interface, when there is no need to display the VSA's main window (demod results are to be captured from the traces for external processing), setting the Application.IsVisible property to false can result in significant speed gains. Also, when several demodulation parameters need to be updated at the same time, using Measurement.NewChangeGroup will result in a significant speed increase.
Another important factor affecting measurement speed is the frequency span setting. Generally, narrower spans are faster and wider spans are slower.
By default, the demodulator performs autodetection of allocated resource blocks. In some cases, this has a noticeable impact on measurement speed. When you know the allocations of the user channels, you can turn off the autodetection and manually specify the allocations (or use the Copy Auto to Manual button). This is done on the Profile tab of the LTE Demod Properties dialog.
Sync slot autodetection in uplink can also affect measurement speed. You can speed up the measurement by clearing parameter in the LTE Allocation Editor for the channel selected for synchronization (see Sync Type) and then defining the sync slot manually. See Uplink user allocations for more information.
The Extended Freq Lock parameter, when selected, will slow down the measurement speed noticeably. You can clear this parameter after setting the center frequency within 7.5 kHz kiloHertz: A radio frequency measurement (one kilohertz = one thousand cycles per second). of the signal's actual center frequency.
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