The iPhone presented at the keynote from October 30, 2018 are all equipped with the same 4G modem made by the giant Intel. However, theiPhone XR supports 2 × 2 MIMO, whileiPhone XS and XS Max have 4 × 4 MIMO antennas. Recently, PCMag has carried out several tests to measure the 4G performance of each smartphone. Unsurprisingly, the iPhone XR is way below the iPhone XS. It even has performances similar to those of theiPhone X released a year earlier.
MIMO (Multiple-Input Multiple-Output, for Multiple inputs, multiple outputs in French) is a multiplexing technique used in mobile networks which allows data transfers with a higher speed and a longer range than with conventional SISO antennas (Single-Input Single-Output). MIMO uses several antennas on both the transmitter and the receiver (the smartphone).
The test performed consists in varying the power of the 4G antenna to simulate a real environment. When conditions deteriorate, the iPhone XS maintains a good connection and good speed, while the iPhone XR loses the connection faster. With the test on a 2 × 2 MIMO antenna, the iPhone XS is once again much better than the iPhone XR.