What does 1x1 stream or 2x2 stream refer in WiFi?

 

In wireless communications like Wi-Fi, 1x1 or 2x2 refer to the number of transmitters and receivers. 1x1 meant 1 transmitter and 1 receiver. 2x2 has 2 transmitters and 2 receivers. Obviously, with 1x1 configuration, the data rate is less, power consumption is also less. 1x1 and 2x2 are also mentioned as streams. Streams help to communicate with multiple devices. MIMO technology is not supported by 1x1 configuration. Standard like 802.11n supports up to 4x4 stream.