Hello, everyone!
Today, I will continue to write about WiFi. In this article, I will explain basic information about MIMO technology.
MIMO is short for Multiple Input Multiple Output. It is an antenna system that uses multiple antennas to send and multiple antennas to receive. In this way, the channel capacity is multiplied and the quality of wireless transmission is improved.
Principle of operation of the MIMO system - the same data is transmitted through several antennas in the same bandwidth. The signals on the receiving antennas come in different ways, and in this way, the reliability of the reception is increased. Using the MIMO system reduces the possibility of data loss.
Based on the number of antennas that transmit and receive the signal, the MIMO system is divided into:
SISO (Single Input Single Output)
SIMO (Single Input Multiple Output)
MISO (Multi-Input Single Output)
MIMO (Multiple Input Multiple Output)
SIMO and MISO are variants of the MIMO system. In general, by using more antennas for transmission and reception, you can significantly increase the transmission speed, up to 50%. It depends on the number of antennas. These systems have improved WiFi standards.
Figure 1. The basic structure of a MIMO system
(https://www.everythingrf.com/community/what-is-mimo-technology)
MIMO systems can also be divided according to the number of users with whom there is simultaneous communication:
SU-MIMO (Single User - MIMO)
MU-MIMO (Multi User - MIMO)
In the next figures, we can see SU-MIMO and MU-MIMO systems.
Figure 2. SU-MIMO and MU-MIMO
(https://laptopsuggest.com/about-technology/what-is-mu-mimo)
MU-MIMO allows simultaneous communication with multiple users, while SU-MIMO uses multiple antennas to communicate with only one device at a time. MU-MIMO is very important for locations with a large number of users - offices, airports, restaurants, cafes, etc.
MU-MIMO was introduced with WiFi 5. This standard only supported 4x4 DL MU-MIMO (Downlink MU-MIMO). With WiFi 6 standard, 8x8 DL MU-MIMO is used. In addition, UL MU-MIMO (Uplink MU-MIMO) was introduced for WiFi 6.
In the next article, I will continue to explain WiFi >> WiFi (5): WiFi device placement
Thank you!
