Few things in communications have had a bigger impact than the Alamouti code in the last 2 decades. Before this, it wasn't possible to send and receive from multiple antennas on the same band simultaneously. This paper opened the doors for transmit & receive side diversity, allowing unprecedented increases in bandwidth at which you could transmit wireless data.<p>Here is the original paper: <a href="https://ieeexplore.ieee.org/document/730453" rel="nofollow noreferrer">https://ieeexplore.ieee.org/document/730453</a>