:''This article deals with coherent space–time block codes (STBCs). For differential space–time block codes, see [[differential space-time code]]s.
'''Space–time block coding''' is a technique used in [[wireless|wireless communications]] to simultaneously transmit multiple copies of a data streamstreams across a number of [[antenna (radio)|antenna]]s and to exploit the various received versions of the data to improve the reliability of data-transfer. The fact that transmitted data must traverse a potentially difficult environment with [[scattering]], [[reflection (physics)|reflection]], [[refraction]] and so on as well as be corrupted by [[thermal noise]] in the [[receiver]] means that some of the received copies of the data will be 'better' than others. This redundancy results in a higher chance of being able to use one or more of the received copies of the data to correctly decode the received signal. In fact, space–time coding combines ''all'' the copies of the received signal in an optimal way to extract as much information from each of them as possible.
