MIMO stands for “multiple input, multiple output.” A 4×4 MIMO device has four antennas for four simultaneous data streams, while a 2×2 MIMO has two. The iPhone XR is 2×2 MIMO, while the iPhone XS and XS Max are 4×4 MIMO.
What Is MIMO?
MIMO is an integral part of modern wireless communications technologies, whether you’re talking about 802.11ac Wi-Fi or 4G LTE cellular data.
Traditionally, a device had just a single antenna inside it. This would be called a 1×1 MIMO device because it has one antenna and can support one data stream at once.
However, there are also devices with more antennas. A 2×2 MIMO device has two antennas for two simultaneous data streams, a 3×3 MIMO device has three antennas for three data streams, and a 4×4 MIMO device has four antennas for four data streams.
More MIMO, More Speed
Each antenna on a device is used both for receiving data and sending data. The more antennas your device has, the more data it can transfer at once—and that means faster wireless download and upload speeds.
Think of it like lanes on a highway. If you have a four line highway, more traffic can flow through at the same time than on a two or one lane highway.
Going from 1×1 MIMO to 4×4 MIMO means quadrupling the theoretical maximum data transfer speed. That’s because each antenna supports a separate data stream up to a maximum theoretical limit. The precise limit varies depending on the wireless networking standing they’re using.
These faster speeds to require you’re connected to a cellular network that supports 4×4 MIMO. It won’t work everywhere on every carrier, but cellular carriers have been gradually rolling out this feature on their networks across the USA for a few years now.
More MIMO Means a Better Signal, Too
