IQ Freq Meas (NB-IoT)

Menu Path (uplink): Trace > Data > Layer N > IQ Freq Meas

IQ Freq Meas shows the IQ data taken after the OFDM Orthogonal Frequency Division Multiplexing: OFDM employs multiple overlapping radio frequency carriers, each operating at a carefully chosen frequency that is Orthogonal to the others, to produce a transmission scheme that supports higher bit rates due to parallel channel operation. OFDM is an alternative tranmission scheme to DSSS and FHSS. symbol FFT Fast Fourier Transform: A mathematical operation performed on a time-domain signal to yield the individual spectral components that constitute the signal. See Spectrum. has been performed on the measured data. This trace is available only for uplink signals.

When there are multiple tones, NPUSCH IQ values shown on the IQ Freq Meas trace resemble a collection of random points concentrated around the origin as a result of the SC-FDMA Frequency Division Multiple Access: Method of allowing multiple users to share the radio frequency spectrum by assigning each active user an individual frequency channel. In this practice, users are dynamically allocated a group of frequencies so that the apparent availability is greater than the number of channels. modulation.

Only the points of channels/signals selected in Composite Include are shown on this trace. The color of a point indicates which channel/signal the point belongs to. The colors of the channel/signals are shown in the Frame Summary trace.

The information on this trace comes from the data in the Measurement Interval.

The data in IQ Freq Meas, which comes from the Time trace data after being processed by the demodulator, is a 2x2 matrix with frequency along one dimension and time along the other. In addition, each one of the points in the matrix is a complex value; therefore, there are 4 total dimensions. The choice of trace format determines which two dimensions will be on the x-y plane, and which dimensions will be overlapped, averaged, or ignored. The relevant trace formats and their corresponding view of the data are described below.

• Constellation, IQ - The I-Q plane is mapped to the x-y plane and each point contains both a subcarrier and a symbol-time reference. In other words, each point plotted on the complex plane came from a complex value transmitted on a specific subcarrier at a certain time.
• LogMag, LinMag, Real, Imag, Wrapped Phase, Unwrapped Phase - Subcarriers are plotted along the x-axis. All the modulation symbols transmitted on a subcarrier have been plotted above the corresponding subcarrier tick on the x-axis, in the specified format (whether it be dB magnitude or the real value of the symbol point, etc.).

See Also

IQ Meas

IQ Ref

IQ Freq Ref

Available Trace Data