Beam Weights (5G NR/5G-Advanced)
There are two types of traces in the Trace > Data > Demod and MIMO Multiple Input, Multiple Output: A physical layer (PHY) configuration in which both transmitter and receiver use multiple antennas. menus that display component carrier data: CCn (component carrier is fixed), and Selected Display CC (component carrier is dynamically selected using the Display parameter). See About Per-Carrier Trace Types for more information.
The trace displays beam weights results for the physical channels included using the Beam Patterns Include parameter. The beam weights data can be viewed as a transformed representation of the Power and Phase data in the MIMO Info table.
The results are normalized by the peak magnitude of the beam weights for that physical channel. For example, for 2X2 MIMO:
On signal generator side:
SSB’s beam weights are [1, -0.8; 0.4j, -0.2j];
PDSCH0’s beam weights are [0.5, -0.4; 0.2j, -0.1j];
On VSA side:
SSB’s beam weights are normalized by 1, which is the peak magnitude of the beam weights, and dividing the weights by this factor will result in [1, -0.8; 0.4j, -0.2j];
PDSCH0’s beam weights are normalized by 0.5, which is the peak magnitude beam weights, and dividing the weights by this value will result in [1, -0.8; 0.4j, -0.2j];
The beam weights data is provided for the first user listed in the MIMO Info table.
Displayed angles are in units of degrees.
Name - Each beam is assigned a name by the VSA software based on the physical channel(s) selected by the Beam Patterns Include parameter:
SSB - SSBn_Periodn_Blockn
PDSCH Physical Downlink Shared Channel - PDSCHn_Layern
PUSCH - PUSCHn_Layern
CSI channel state information-RS - CSI-RSn_Portn
Chn - Specifies the input channel.
Display formats
The display format is selected using the Advanced tab's Beam Weights Format parameter. The formats are as follows:
When Beam Weights Format is set to Cartesian (I+jQ), this trace displays beam weight data in I+jQ format.
When Beam Weights Format is set to Polar (A ∠ B deg), this trace displays beam weight data in polar form with linear magnitude and phase (in degrees).
When Beam Weights Format is set to Log Mag Polar (A dB ∠ B deg), this trace displays beam weight data in polar form with log magnitude (in dB) and phase (in degrees).
See Also
