IQGainImb (LTE-Advanced)
shows the amount of amplifier gain imbalance between I and Q for a C-RS Cell-specific RS antenna port over all VSA measurement channels (Rx0 = Measurement Channel 1). is computed by calculating the ratio of I to Q for each pair of PDSCH Physical Downlink Shared Channel subcarriers symmetric about the DC axis and then linearly averaging the ratios.
is calculated over all PDSCH subcarriers in the Measurement Interval.
is calculated for each C-RS antenna port. When a C-RS/Rx path is present, the MIMO Info Table will show the IQ gain imbalance for the corresponding C-RS antenna port. C-RS/Rx paths with the same C-RS antenna port but different measurement channels will show the same value.
The will show "---" for IQ data results that cannot be calculated from the demodulated data. Cases where the IQ metrics cannot be calculated are as follows:
- The signal has the Precoding mode set to (Spatial Multiplexing), CDD set to , and the number of layers is less than the number of transmit antennas.
- The signal has only UE-RS UE-specific Reference Signal PDSCH allocations (data results do not include PDSCH transmitted on UE User Equipment (e.g. cell phone)-RS antenna ports).
- The signal in the Measurement Interval does not contain at least one PDSCH subcarrier that has a corresponding PDSCH subcarrier in the frequency-mirrored location on the other side of the DC axis.
- The transmitted data is identical on two or more layers and Codebook Idx is set to zero.
- The number of measurement channels is less than the number of C-RS antenna ports.
See Also
