Method for testing a multiple-input and multiple-output device and test system

A method of using a test system to test a multiple-input and multiple-output device, said device comprising at least two receiving antennas, comprising the following steps:

• a) directing the test system to transmit a first test signal via a first transmission antenna of said test system,
• b) measuring, with the test system, the first test signal via each receiving antenna of said device,
• c) directing the test system to transmit at least a second test signal via a second transmission antenna of said test system,
• d) measuring, with the test system, the second test signal via each receiving antenna of said device,
• e) directing the test system to transmit further transmitting signals via the transmission antennas in pairs wherein a phase difference is set between the phases of said transmitting signals transmitted via the pair of transmission antennas,
• f) measuring, with the test system, said further transmitting signals via each receiving antenna of said device, and
• g) determining, with the test system, a channel matrix based on the further transmitting signals measured via each receiving antenna of said device.