Bandwidth limitation and channel fading are two major problems in wireless communication systems. In the late 90’s, it was shown that the capacity of a fading channel is substantially increased by using multiple antennas in the transmitter and receiver. Such communication systems are referred to as multiple-input multiple-output (MIMO) systems. The gain in the capacity of a MIMO system can be attributed to the spacial diversity that such systems provide in coping with channel fading. In order to approach the large theoretical capacity of a MIMO system, it is necessary to perform a combined form of coding and modulation involving both the time domain and the space domain (i.e. involving multiple input antennas of the system). This type of combined coding and modulation is referred to as space-time coding .
