MIMO technology can greatly improve the throughput and coverage distance of the system on the basis of no additional increase in bandwidth and transmit power, and has been widely used in WLAN products and equipment. The introduction of 4*4 MIMO from WIFI4 to WIFI7 can support up to 16*16 MIMO, with the increase in the number of antennas, it will also bring about an increase in the design complexity and cost of the system transceiver, digital signal processing unit and other hardware, as well as bring new challenges to the system function and performance testing.

The basic requirements for MIMO performance are uncorrelated signals between channels, good isolation, and strict clock synchronization of multiple signals in both baseband and RF. These requirements can only be verified by observing all antenna paths simultaneously under the simultaneous operation of multiple antennas in a MIMO system. The actual RF performance of the system cannot be verified by switching the RF switches and taking turns to test a single channel. Because multiple vector signal analyzers are needed to analyze the signals and multiple vector generators are needed to transmit the signals, the complexity and cost of MIMO testing is significantly higher than that of a SISO system.

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Quasi-Electronics wireless synthesizer T6290F, a single instrument with two independent vector signal generator and vector signal analyzer, the highest frequency band up to 10GHz, the analysis bandwidth of up to 2GHz, a single instrument can test 2x2 MIMO, through the cascade can be tested 4x4 MIMO, 8 * 8 MIMO, 16 * 16 MIMO and so on. Meanwhile, it supports 802.11n, 802.11ac, 802.11ax, 802.11be protocol testing, and can test each stream's indexes including Power, EVM, Lo Leakage, Frequency Error, Spectrum Mask, etc. at one time.

WIFI7 (320MHz, 2x2 MIMO) signal test as an example, you can access the DUT's ANTO to the instrument's RF1.1 port, ANT2 access to the instrument's RF1.2 port, configure the DUT MIMO signals, configure the instrument's WIFI basic settings, click on the Start button to correctly parse the WIFIMIMO signal.

DUTs with 4*4 MIMO capability can perform 4*4 MIMO testing by cascading as follows.

Test results