SISO, SIMO, MISO and MIMO
The wireless data transmission system consists of two parts: the transmitter and the receiver, whereby data is transmitted into the air from the antenna of the transmitter and received by the antenna of the receiver.
The different forms of antenna technology refer to multiple inputs and outputs. In this way the input is the transmitter as it transmits into the link , and the output is the receiver. It is at the output of the wireless link.
There is a number of different MIMO configurations . These are termed SISO, SIMO, MISO and MIMO.
* SISO – Single Input Single Output
A system which uses a single antenna at the transmitter and the receiver is named Single Input Single Output (SISO). It is used in radio and TV broadcast and our personal wireless technologies (e.g. Wi-Fi and Bluetooth).
*SIMO – Single Input Multiple output
A system which uses a single antenna at the transmitter and multiple antennas at the receiver is named Single Input Multiple Output (SIMO). This is also known as receive diversity. It is often used to enable a receiver system that receives signals from a number of independent sources to combat the effects of fading
*MISO – Multiple Input Single Output
A system which uses multiple antennas at the transmitter and a single antenna at the receiver is named Multiple Input Single Output (MISO). MISO is also termed transmit diversity. A technique known as Alamouti Space Time Coding (STC) is employed at the transmitter with two antennas, allowing the transmitter to transmit signals both in time and space. This means data is transmitted by the two antennas at two different times consecutively.
*MIMO – Multiple Input multiple Output
A system which uses multiple antennas at the transmitter and a receiver is named Multiple Input Multiple Output (MIMO). A MIMO system with similar count of antennas at both the transmitter and the receiver in a point-to-point (PTP) link is able to multiply the system throughput linearly with every additional antenna. For example, a 2×2 MIMO will double the throughput.
Because it offers significant increases in data throughput and link range without additional bandwidth or transmit power, MIMO is commonly used in today’s wireless technology, including 802.11n WiFi, WiMAX, LTE, etc.