A method for self-testing of a system comprising a radio system comprising two or more Radio Frequency Integrated Circuits, RFICs, (104-1 - 104-4) each comprising a plurality of antenna elements (AE1 - AE4), Local Oscillator, LO, generation circuitry comprising a frequency divider and being configured to generate a LO signal based on a reference LO signal from an external LO source, and processing circuitry (118, 120) configured to, based on the LO signal, upconvert signals to be transmitted via the plurality of antenna elements (AE1-AE4) and/or downconvert signals received via the plurality of antenna elements (AE1 - AE4), wherein the method comprises, for a first RFIC pair comprising two of the two or more RFICs (104-1 - 104-4), namely a first RFIC and a second RFIC: obtaining a first power measurement for the first RFIC pair via a receive antenna element comprised in either the first RFIC or the second RFIC while a test signal is transmitted via a first transmit antenna element comprised in the first RFIC and a second transmit antenna element comprised in the second RFIC and a phase state of the second RFIC is a first LO phase state, wherein: • the first transmit antenna element is one of the plurality of antenna elements (AE1 - AE4) comprised in the first RFIC that is configured as a transmit antenna element; • the second transmit antenna element is one of the plurality of antenna elements (AE1 - AE4) comprised in the second RFIC that is configured as a transmit antenna element; and • the receive antenna element is either: (a) one of the plurality of antenna elements (AE1 - AE4) comprised in the first RFIC that is configured as a receive antenna element or (b) one of the plurality of antenna elements (AE1 - AE4) comprised in the second RFIC that is configured as a receive antenna element; obtaining a second power measurement for the first RFIC pair via the receive antenna element while the test signal is transmitted via the first transmit antenna element and the second transmit antenna element and the phase state of the second RFIC is a second LO phase state; determining which of the first LO phase state and the second LO phase state for the second RFIC results in phase alignment between the LO signals for the first RFIC and the second RFIC based on a predetermined relationship between power measurements and phase alignment between the LO signals for the first RFIC and the second RFIC; and setting the phase state of the second RFIC to the determined LO phase state. obtaining a first power measurement for the first RFIC pair via a receive antenna element comprised in either the first RFIC or the second RFIC while a test signal is transmitted via a first transmit antenna element comprised in the first RFIC and a second transmit antenna element comprised in the second RFIC and a phase state of the second RFIC is a first LO phase state, wherein: • the first transmit antenna element is one of the plurality of antenna elements (AE1 - AE4) comprised in the first RFIC that is configured as a transmit antenna element; • the second transmit antenna element is one of the plurality of antenna elements (AE1 - AE4) comprised in the second RFIC that is configured as a transmit antenna element; and • the receive antenna element is either: (a) one of the plurality of antenna elements (AE1 - AE4) comprised in the first RFIC that is configured as a receive antenna element or (b) one of the plurality of antenna elements (AE1 - AE4) comprised in the second RFIC that is configured as a receive antenna element; • the first transmit antenna element is one of the plurality of antenna elements (AE1 - AE4) comprised in the first RFIC that is configured as a transmit antenna element; • the second transmit antenna element is one of the plurality of antenna elements (AE1 - AE4) comprised in the second RFIC that is configured as a transmit antenna element; and • the receive antenna element is either: (a) one of the plurality of antenna elements (AE1 - AE4) comprised in the first RFIC that is configured as a receive antenna element or (b) one of the plurality of antenna elements (AE1 - AE4) comprised in the second RFIC that is configured as a receive antenna element; obtaining a second power measurement for the first RFIC pair via the receive antenna element while the test signal is transmitted via the first transmit antenna element and the second transmit antenna element and the phase state of the second RFIC is a second LO phase state; determining which of the first LO phase state and the second LO phase state for the second RFIC results in phase alignment between the LO signals for the first RFIC and the second RFIC based on a predetermined relationship between power measurements and phase alignment between the LO signals for the first RFIC and the second RFIC; and setting the phase state of the second RFIC to the determined LO phase state.