MIMO Common Pilot Error (802.16 OFDMA)
When OFDMA is enabled, the trace data shows the difference between the measured and ideal pilot subcarrier symbols as decoded by the Matrix Decoder. The CPE error summary data provides the RMS level of the Common Pilot Error trace data as a percentage of the ideal signal.
Residual phase and frequency settling that occurs following the preamble is measured via the trace data. With Track Phase is selected, this trace data shows the average phase error of the active OFDMA pilots as a function of time (versus data symbol number). To convert to frequency units, select Trace Format equal Group Delay.
At each symbol-time in the burst, the measured symbol values of the active pilot subcarriers are compared with the ideal values. The differences are averaged together, producing a single complex value for each symbol-time. Normally the phase of this trace is displayed, showing how the pilot phase changes over the burst. When Track Amplitude is enabled, the magnitude of this trace will help see signal magnitude changes over the burst.
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