Local oscillator phase synchronization for beamforming and MIMO

A wireless circuit comprising:

• a first radio frequency (RF) front-end circuit and a second RF front-end circuit, each of said first and second RF front-end circuits comprising a mixer configured to mix an input signal SI with a mixing signal Smix (m) to generate an output signal Sout(m) for that RF front-end circuit;
• a reference circuit configured to generate a reference signal SR common to the first and second RF front-end circuits;
• and
• a plurality of time measurement circuits, one for each of the first and second RF front-end circuits, each time measurement circuit operatively connected to an input of the corresponding mixer and the reference circuit and configured to measure a time difference Δt(m) between a start edge of the reference signal tedge(SR) and a stop edge of the mixing signal tedge (Smix(m)) of the corresponding RF front-end circuit, wherein the start edge defines a beginning of a measurement period and wherein each stop edge defines an end of the measurement period for the corresponding RF front-end circuit;
• wherein the wireless circuit is configured to determine the initial phase Δϕi(m) of each output signal from the time difference measured for the corresponding RF front-end circuit;
• and
• wherein the first and second RF front-end circuits both comprise transmission RF front-end circuits or the first and second RF front-end circuits both comprise reception front-end circuits.

A wireless transceiver comprising a wireless circuit, the wireless circuit comprising:

• a first radio frequency (RF) front-end circuit and a second RF front-end circuit, each of said first and second RF front-end circuits comprising a mixer configured to mix an input signal SI with a mixing signal Smix (m) to generate an output signal Sout (m) for that RF front-end circuit;
• a reference circuit configured to generate a reference signal SR common to the first and second RF front-end circuits;
• and
• a plurality of time measurement circuits, one for each of the first and second RF front-end circuits, each time measurement circuit operatively connected to an input of the corresponding mixer and the reference circuit and configured to measure a time difference Δt(m) between a start edge of the reference signal tedge(SR) and a stop edge of the mixing signal tedge(Smix(m)) of the corresponding RF front-end circuit, wherein the start edge defines a beginning of a measurement period and wherein each stop edge defines an end of the measurement period for the corresponding RF front-end circuit;
• wherein the wireless circuit is configured to determine the initial phase Δϕi(m) of each output signal from the time difference measured for the corresponding RF front-end circuit;
• and
• wherein the first and second RF front-end circuits both comprise transmission RF front-end circuits or the first and second RF front-end circuits both comprise reception front-end circuits.

A method of determining an initial phase of each output signal generated by first and second radio frequency (RF) front-end circuits, each of said first and second RF front-end circuits comprising a mixer configured to mix an input signal SI with a mixing signal Smix (m) to generate the output signal Sout (m) for that RF front-end circuit, the method comprising:

• generating a reference signal SR common to the first and second RF front-end circuits;
• for each of the first and second RF front-end circuits, measuring a time difference Δt(m) between a first edge of the reference signal tedge(SR) and a second edge of the corresponding mixing signal tedge(Smix(m));
• and
• determining the initial phase Δϕi(m) of each output signal from the time difference measured for the corresponding RF front-end circuit;
• wherein the first and second RF front-end circuits both comprise transmission RF front-end circuits or the first and second RF front-end circuits both comprise reception front-end circuits.

A wireless transceiver comprising a wireless circuit, the wireless circuit comprising:

• a first radio frequency (RF) front-end circuit and a second RF front-end circuit, each of said first and second RF front-end circuits comprising a mixer configured to mix an input signal SI with a mixing signal Smix (m) to generate an output signal Sout (m) for that RF front-end circuit;
• a reference circuit configured to generate a reference signal SR common to the first and second RF front-end circuits;
• and
• a plurality of time measurement circuits, one for each of the first and second RF front-end circuits, each time measurement circuit operatively connected to an input of the corresponding mixer and the reference circuit and configured to measure a time difference Δt (m) between a first edge of the reference signal tedge(SR) and a second edge of the mixing signal tedge(Smix(m)) of the corresponding RF front-end circuit;
• wherein the wireless circuit is configured to determine the initial phase Δϕi(m) of each output signal from the time difference measured for the corresponding RF front-end circuit;
• and
• wherein the first and second RF front-end circuits both comprise transmission RF front-end circuits or the first and second RF front-end circuits both comprise reception front-end circuits.