What is the precoding matrix used for single-layer transmission with four antenna ports and transform precoding disabled?
Precoding matrix  for two-layer transmission using four antenna ports with transform precoding disabled.
Precoding matrix  for two-layer transmission using two antenna ports with transform precoding disabled.
Precoding matrix  for single-layer transmission using four antenna ports with transform precoding disabled.
Precoding matrix  for three-layer transmission using four antenna ports with transform precoding disabled.