Sync Corr (802.16 OFDMA)
Sync Corr (Sync Correlation) is the correlation coefficient between the measured preamble and an ideal preamble. This can be used as an indication of the quality of the preamble. A value of 1 indicates perfect correlation and a value of 0 indicates no correlation.
Sync Corr (Sync Correlation) is the normalized autocorrelation peak of the signal. This can be used as an indication of the quality of the basic 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 format. A value of 1 indicates perfect correlation and a value of 0 indicates no correlation. A low correlation value could be due to mismatched parameters between the signal and the 89601 setup, such as , , or . The problem could also be due to signal creation problems like an incorrect windowing implementation.
Large Frequency Errors and Incorrect Sync Corr Values
Large frequency errors may cause the VSA to show incorrect low Sync Corr values. These values are a result of frequency error and do not necessarily indicate poor signal quality. Therefore, for low Sync Corr values you always need to validate the cause of the low Sync Corr data result.
If the Sync Corr is low and the frequency error is large, check the RCE (EVM). If the RCE Relative Constellation Error is the RMS level of the Error Vector Magnitude, averaged over all subcarriers and all detected OFDM symbols. (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 low, the measured signal data is good and the low Sync Corr value can generally be ignored. To correct for frequency errors, adjust the center frequency so that the Freq Err decreases to approximately 0 Hz. If the Sync Corr increases in value then the contributing factor to the initial low Sync Corr value was the frequency error and not the measured signal.
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