Transmit Diversity
MISO = Multiple Input Single Output
Principle
  • More complex than SISO.
  • 2 or more transmitters and one receiver.
  • MISO is more commonly referred to as transmit diversity.
  • The same data is sent on both transmitting antennas but coded in such a way that
    the receiver can identify each transmitter.
Benefits
  • Transmit diversity increases the robustness of the signal to fading and can increase
    performance in low Signal-to-Noise Ratio (SNR) conditions.
  • It does not increase data rates as such, but rather supports the same data rates using
    less power.
When the eNodeB uses 2 antennas in DL to transmit twice the same data, it is the diversity in transmission, also called the TxDiv. It improve the quality and the coverage at the cell edge.
Receive Diversity
SIMO = Single Input Multiple Output 
Principle 
  • It uses one transmitter and 2 or more receivers.
  • It is often referred to as receive diversity.
Benefits 
  • It is particularly well suited for low SNR conditions in which a theoretical gain of 3 dB
  • is possible when two receivers are used. 
  • No change in the data rate since only one data stream is transmitted, but coverage
  • at the cell edge is improved due to the lowering of the usable SNR.