Multiple input multiple output (MIMO) is a multi-antenna method that uses multipath propagation to boost data rates in wireless communications. The transmit and receive antennas must be spatially separated from each other. The compact design of mobile devices such as smartphones is a limiting factor. These devices can hold at most two transmit and two receive antennas, which limits transmission to 2x2 MIMO.
At Mobile World Congress 2019 in Barcelona, Rohde & Schwarz unveiled a test solution for WLAN 2x2 MIMO stations in line with the IEEE 802.11ax standard. Using the well-established R&S CMW270 wireless connectivity tester, developers can test the RF characteristics of both transmitters and receivers. This solution also allows them to determine the data throughput in the transmit and receive directions.
In signaling mode, the R&S CMW270 emulates a WLAN 11ax access point (AP) to which the DUT, a WLAN station, is connected in normal mode. Unlike commonly used non-signaling mode, tests and measurements in signaling mode have the advantage that the user performs them under realistic conditions and does not need wired remote control with device-specific control software for the DUT.
The R&S CMW270 is ideal for more than just signaling tests in line with the IEEE 802.11a/b/g/n/ac/ax WLAN standards. It can also comprehensively and simultaneously test Bluetooth® devices, for example. The R&S CMW270 also supports RF tests for ZigBee and Thread components in line with IEEE 802.15.4.
The WLAN 2x2 MIMO 11ax signaling solution was presented to the general public at Mobile World Congress 2019.