3GPP-defined 16QAM EVM (LTE-Advanced)
is the average 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. for PDSCH Physical Downlink Shared Channel 16QAM allocations. This EVM average is calculated according to 3GPP TS Technical Specification 36.141, Section F.4.1. This average includes all subframes in the Measurement Interval.
Data EVM and 3GPP-defined EVM summary table results may not exactly match since the standard requires that 3GPP-defined EVM be calculated per slot and then averaged over the measurement interval whereas all other EVM results computed by the demodulator are calculated per symbol and then averaged over the measurement interval.
Section F.4.2 of 3GPP TS 36.141 specifies that 10 downlink subframes should be used to compute the the EVM average.
For TDD Time Division Duplex: A duplexing technique dividing a radio channel in time to allow downlink operation during part of the frame period and uplink operation in the remainder of the frame period. signals, Section F.4.2.1 of 3GPP TS 36.141 specifies that minimum number of frames be used so that at least 10 downlink subframes are included in the EVM average.
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