As is true for single-input single-output (SISO) communication links, there are many approaches for coding multiple-input multiple-output (MIMO) systems in an attempt to approach the channel capacity. Many of the space-time coding approaches have analogs in the SISO regime. The multiple antennas of MIMO systems enable spatial diversity, increased data rates, and interference suppression. In general, there are trades in these characteristics, depending upon the coding and receiver approach. One of the most important trade-offs in this regard is the trade-off between data rate and diversity whereby the data communication rate is reduced to improve probability of error or outage. That is to say, a fraction of the data rate is sacrificed to improve robustness.
There have been numerous contributions in the field of space-time coding. The major contributions include References [8, 99, 307, 305, 306, 361, 362, 314, 57, 58, 292, 86, 207, 166, 119, 87, 222, 270, 42, 43, 269, 226, 196]. Of particular note are Reference  which introduced what is now known as the Alamouti code, a simple and elegant space-time code for systems with two transmitter antennas, Reference  which introduced systematic methods to evaluate space-time codes, and Reference  which analyzed the fundamental trade-offs between diversity and rate in multiantenna systems.