EVM (802.16 OFDMA)
EVM Error vector magnitude (EVM): A quality metric in digital communication systems. See the EVM metric in the Error Summary Table topic in each demodulator for more information on how EVM is calculated for that modulation format. is the RMS level of the Error Vector Magnitude, averaged over all subcarriers (inluding Pilot and Data subcarriers) and all detected OFDMA symbols. EVMis computed in dB and as a percentage (%rms).
For software versions 8.1 and earlier, EVM was identified as RCE Relative Constellation Error is the RMS level of the Error Vector Magnitude, averaged over all subcarriers and all detected OFDM symbols.(EVM) in the and Tables.
When making measurements of DL Down Link (forward link: from base station to cell phone)-PUSC partial usage of subchannels: Some of the subchannels are allocated to the transmitter. data bursts that occupy fewer slots than allocated, the allocated-but-unoccupied slots will be used when computing error metrics (like DataRCE). Therefore, if many slot are unoccupied, but allocated, these metrics may include significant error power which is not present on data carrying subcarriers. This occurs automatically when an analyzed DL-PUSC data burst is detected as having allocated-but-unoccupied slots (relative to the decoded DL-MAP downlink map: A MAC message that defines burst start time for both time division multiplex and time division multiple access (TDMA) by a subscriber station (SS) on the downlink. or the user-provided zone definition).
There are also RCE results for the Data subcarriers and Pilot subcarrieres, see the DataRCE and Pilot RCE topics respectively.
Additional signal analysis metric summary tables
For additional EVM and RCE metrics see the following summary tables:
Data Burst Info Table
Frame Summary Table
See Also
