Multiple-Input Single-Output (MISO) is a multiple antenna system which consists of a multiple antenna transmitter and a single antenna receiver. MISO is a subset of MIMO. The capacities of a MISO channel can be represented by open-loop or closed-loop cases. The open-loop capacity can be achieved without downlink channel state information at the transmitter while the closed-loop capacity can be achieved necessarily using downlink channel state information at the transmitter.
In literatures, the open-loop scheme is called as transmit diversity and the closed-loop scheme is called as transmit antenna array. There are also a hybrid approach which combines space time coding techniques originally used for transmit diversity and antenna array beamforming techniques originally used for transmi antenna array.