What Is MIMO?
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.
MIMO is an integral part of modern wireless communications technologies, whether you’re talking about 802.11ac Wi-Fi or 4G LTE cellular data. MIMO technology is used for both cellular and Wi-Fi connections. But cellular and WI-Fi have separate antennas.
4×4 MIMO is now common on high-end phones like Apple’s iPhone XS and iPhone XS Max. Samsung’s Galaxy S9 and S9+ also support 4×4 MIMO, as do Google’s Pixel 3 and Pixel 3 XL phones.
Recent tests have demonstrated that going from 2×2 MIMO to 4×4 MIMO can give you improved wireless signal strength, too. PC Magazine had Cellular Insights run some tests comparing the iPhone XR to the iPhone XS. The iPhone XR and iPhone XS have the same wireless modem, so the main difference should just be the fewer antennas on the iPhone XR compared to the iPhone XS—2×2 MIMO on the XR versus 4×4 on the X