Antenna ports in 5G new radio
In 5G New Radio or 4G LTE, multiple-input multiple-output (MIMO) transmission is a key technology, especially in downlink. Signals transmitted from the base station through different antennas, or signals subjected to different and, for an unknown receiver, multiple antenna precoding, will have different radio channels, even if the MIMO antennas are in the same location. It is very important for user equipment (UE) to consider certain assumptions about the relationship between radio channels, UEs need to understand which reference signal(s) should be used to estimate the channel for a particular downlink transmission and determine the relevant channel