MIMO Refers to Multiple-Input Multiple-Output

MIMO (Multiple-Input Multiple-Output) technology can be broadly classified into two categories: transmit/receive diversity and spatial multiplexing. Traditional multi-antenna systems are used to enhance diversity gain for mitigating channel fading, where signals carrying identical information are transmitted via different paths. The receiver obtains multiple independently faded copies of data symbols, thereby achieving higher reception reliability. This technique is typically implemented using multi-antenna configurations, which have been extensively studied in mobile communications. From a coding perspective, diversity techniques often employ Alamouti coding schemes to orthogonalize transmission paths, while spatial multiplexing algorithms like Zero-Forcing or MMSE detectors separate layered data streams at the receiver.