Ref C-RS Port (LTE)

Default: Cleared

Range: Cleared or Selected and Port 0-3 depending on the number of C-RS ports

Ref C-RS Port is one of two parameters that determines which C-RS Cell-specific RS/Rx path to use for synchronization and initial equalization and to show on certain non-MIMO Multiple Input, Multiple Output: A physical layer (PHY) configuration in which both transmitter and receiver use multiple antennas. traces (listed below). The Ref C-RS Port parameter determines the transmitted Cell-specific RS antenna port, and the Ref Meas Channel parameter determines the VSA receive channel of the reference path.

When Ref C-RS Port is cleared, the demodulator searches the reference measurement channel for the strongest C-RS antenna port signal and uses that C-RS port as the reference.

When Ref C-RS Port is selected and set to Port (x), antenna port (x) is used as the reference.

C-RS metrics for other C-RS/Rx paths are expressed relative to the C-RS metrics for the reference C-RS/Rx path. For example, when C-RS port 0 and Rx0 (Measurement Channel 1) are selected, the C-RS0/Rx0 section of the MIMO Info Table will show 0 dB for RSPwr and the other C-RS/Rx paths' RSPwr will be expressed in dB relative to this 0 dB point.

In the absence of cross-channel paths (when connecting directly to the transmitter), make sure that the specified C-RS/Rx path is present; otherwise, the signal will not be demodulated.

The Sync Type parameter affects how the reference C-RS/Rx path must be specified.

Sync Type = P-SS (note: Ref Meas Channel must contain P-SS Primary Synchronization Signal)
- Ref C-RS Port selected: the demodulator will use the specified reference C-RS antenna port (which must be present on the Ref Meas Channel).
- Ref C-RS Port cleared: the demodulator will automatically detect the strongest C-RS port signal to use for the reference C-RS port.
Sync Type = RS: reference path autodetection is not supported and the reference C-RS/Rx path must be specified manually using Ref Meas Channel and Ref C-RS Port.

The parameters Ref C-RS Port and Ref Meas Channel determine which C-RS/Rx path results are shown on the following traces:

To view information for all detected C-RS antenna ports, use the MIMO traces (Trace > Data > MIMO).

P-SS and S-SS Secondary Synchronization Signal must be present in the time capture (Raw Main Time) of the reference measurement channel for successful demodulation to occur. For example, for a two-channel transmit diversity signal that has P-SS and S-SS transmitted only on antenna 2, the demodulator can analyze antenna 2 without antenna 1 connected, but not vice versa.