Selection combining involves the process of selecting one of the multiple receiver antennas and thus the communication channel which is least affected by noise.

The question: Is it possible to use this technique if there are more than two transmitter antennas?

My instinct says no, however i need to find out the answer and the reason for it as well.

edited on 22nd April

well the answer is yes as well as know.
for STBC you need to lock into one receiver antenna only during the transmission of a codeword. the receiver antenna cannot be changed during this one code transmission time.

for spatial mux, the best rx antenna can be found and selected after each time slot, but then is difficult and complex to find out which receiver is best cause each time the received signal is a combination from a no of transmitter antennas. It requires a complex mechanism to separately make an estimation of each channel and thus make a combined channel estimations for a single receiver antenna.