# Theory

Learn the MIMO theory.

## Computation of MIMO Results

For the computation of the MIMO result maps, the received power (dBm) and the SNIR (dB) are computed for each defined MIMO stream (according to the specified MIMO scheme) in each receiver pixel. In this context also the interference between different MIMO streams operating on the same carrier (and Signal Group ID) is considered (depending on the selected option. Finally the feasible modulation and coding scheme depending on the given SNIR is selected.

If the serving cell is a MIMO antenna the received power is the superposition of the signal power values from all antennas belonging to the MIMO system and transmitting the same MIMO stream.

Table 1. Antenna type and received power.
Conventional antenna Received power from serving cell
Antenna belonging to distributed antenna system (DAS) Superposition of received power values from all antennas belonging to DAS of serving cell
Antenna belonging to MIMO system Superposition of received power values from all antennas transmitting the same MIMO stream as the serving cell

## Computation of Interference

Usually signals which are radiated on the same carrier but from different antennas interfere with each other as individual signals are transmitted. Signals which are radiated from different antennas but within the same DAS do not interfere (if they have the same Signal Group ID). If the antennas belong to a MIMO system the interference depends on the transmitted MIMO stream. Antennas transmitting the same MIMO stream are considered to operate like a DAS (for example, in a 4x2 MIMO system). If the antennas transmit different MIMO streams they interfere each other depending on the individual situation (spatial separation, usage of different polarizations, LOS/NLOS scenario). The interfering effect can be reflected by selecting the appropriate option on the dialog.

Table 2. Antenna types, MIMO streams and interference.
Antenna 1 Antenna 2 Interference (same carrier)
Conventional antenna Conventional antenna Yes
Conventional antenna Antenna belonging to DAS A Yes
Antenna belonging to DAS A Antenna belonging to DAS A No
Antenna belonging to DAS A MIMO Stream 1 Antenna belonging to DAS A MIMO Stream 1 No
Antenna belonging to DAS A MIMO Stream 1 Antenna belonging to DAS A MIMO Stream 2 Yes
Antenna belonging to DAS A Antenna belonging to DAS B Yes