 Hi, I'm Mr. T-Ward R of Elements. Multiple input and multiple output, or MIMO, is a set of techniques that has gotten a lot of attention in recent years. So what is MIMO? Before we dissect this topic, consider subscribing to our channel, give us a thumbs up or leave a comment. This is the first part of the two MIMO videos, since this topic deserves a bit more space. Consider an example of a single input single output link with a one channel radio connected to a single polarization antenna transmitting RF signal to the same setup at the receiving side. The received signal is not only the one arriving through the line of sight. It fluctuates due to all kinds of fading. In other words, random addition of signals arriving at the receiver because of reflections, when their signal reflects from objects much larger than the wavelength, diffracted signals from the edges of such obstructions, scattering from objects with the size similar to the signal wavelength, flat or frequency-selective fading, affecting all or only certain frequencies of a wideband signal, or Doppler fading, causing frequency shift of a signal when the receiver is moving. All these fading components can severely affect the quality and reliability of a wireless communication system. MIMO is a set of techniques used to diminish the fading effects and improve throughput capacity, coverage and reliability of a wireless link. This is a simple wireless link capacity equation. Besides the higher bandwidth or increasing the signal-to-noise ratio, growing the number of channels on either side of the link is also a way to increase the throughput capacity, which is where MIMO comes in. Increasing the number of antennas on either or both sides of a wireless link creates multiple possible paths for the signal to arrive at the receiver. There are a number of benefits this brings about. First is array gain, which is an increase of received signal SNR from combining the signals arriving from different directions. Array gain improves resistance to noise and therefore the coverage and maximum range of a wireless link. Second is reliability. Multiple paths through which the signal can reach the receiver increases the probability of a successful data transfer. Thirdly, multiple data streams in the same frequency channel enable higher link capacity. The smaller number in an M times N system tells us the minimum number of reliably operable data streams. In wireless internet service provider networks it is common to leverage two independent data streams on each end of a link separated by antenna polarization. This effectively doubles the link capacity despite both polarizations of a antenna use the same frequency. If you enjoy our videos consider subscribing to our channel, leave a comment or give us a thumbs up or check out some other inside of our list videos.