Proximity detection for a beamforming transceiver

An apparatus for a radio frequency front end of a beamforming transmitter or transceiver, the apparatus comprising:

• a dual-polarized antenna element for reception of electromagnetic waves transmitted via an antenna array, comprising the dual-polarized antenna element, of the radio frequency front end and subsequently reflected from at least one obstruction to said dual-polarized antenna element, wherein said dual-polarized antenna element comprises a first feed point for reception of a first polarization and a second feed point for reception of a second polarization, wherein the first polarization and the second polarization comprise different types selected from linear, elliptical or circular polarizations;
• a combiner for combining signals received via the first and second feed points of the dual-polarized antenna element;
• and
• an output for outputting signals received at least via the combiner from the radio frequency front end.

A method comprising:

• causing transmitting, using a beamforming device being one of a radio transmitter and transceiver, electromagnetic waves using a first beam formed by applying a first beamforming configuration to a plurality of electrically tunable phase shifters of a plurality of radio frequency transmitter chains of the beamforming device, wherein the plurality of electrically tunable phase shifters are configured to apply phase shifts to a plurality of antenna elements of an antenna array of the beamforming device and the first beamforming configuration is optimized for transmission to a first beamforming direction while achieving isolation of a pre-defined level between the plurality of antenna elements and a first feed point of a dual-polarized antenna element of the beamforming device corresponding to the first polarization;
• measuring a first signal corresponding to a first polarization via said first feed point of said dual-polarized antenna element and via a switch for switching between reception of the first polarization via the first feed point of the dual-polarized antenna element and reception of the second polarization via a second feed point of the dual-polarized antenna element, the switch being set to a first position for receiving the first polarization, wherein the first signal corresponds to the electromagnetic waves transmitted using the first beam and subsequently reflected from at least one obstruction towards said dual-polarized antenna element;
• causing transmitting, using the beamforming device, electromagnetic waves using a second beam formed by applying a second beamforming configuration to the plurality of electrically tunable phase shifters, wherein the second beam has the same polarization as the first beam and the second beamforming configuration is optimized for transmission to the first beamforming direction while achieving isolation of a pre-defined level between the plurality of antenna elements and the second feed point of the dual-polarized antenna element corresponding to the second polarization;
• measuring a second signal corresponding to a second polarization via said second feed point of said dual-polarized antenna element and the switch, the switch being set to a second position for receiving the second polarization, wherein the second signal corresponds to the electromagnetic waves transmitted using the second beam and subsequently reflected from at least one obstruction towards said dual-polarized antenna element;
• performing proximity detection based on the measured first and second signals;
• and
• causing adjusting transmit power of the beamforming device based on results of the proximity detection.

A non-transitory computer readable medium comprising program instructions that, when executed by an apparatus, cause the apparatus to perform at least the following:

• causing transmitting, using a beamforming device being one of a radio transmitter and transceiver, electromagnetic waves using a first beam formed by applying a first beamforming configuration to a plurality of electrically tunable phase shifters of a plurality of radio frequency transmitter chains of the beamforming device, wherein the plurality of electrically tunable phase shifters are configured to apply phase shifts to a plurality of antenna elements of an antenna array of the beamforming device and the first beamforming configuration is optimized for transmission to a first beamforming direction while achieving isolation of a pre-defined level between the plurality of antenna elements and a first feed point of a dual-polarized antenna element of the beamforming device corresponding to the first polarization;
• measuring a first signal corresponding to a first polarization via said first feed point of said dual-polarized antenna element and via a switch for switching between reception of the first polarization via the first feed point of the dual-polarized antenna element and reception of the second polarization via a second feed point of the dual-polarized antenna element, the switch being set to a first position for receiving the first polarization, wherein the first signal corresponds to the electromagnetic waves transmitted using the first beam and subsequently reflected from at least one obstruction towards said dual-polarized antenna element;
• causing transmitting, using the beamforming device, electromagnetic waves using a second beam formed by applying a second beamforming configuration to the plurality of electrically tunable phase shifters, wherein the second beam has the same polarization as the first beam and the second beamforming configuration is optimized for transmission to the first beamforming direction while achieving isolation of a pre-defined level between the plurality of antenna elements and the second feed point of the dual-polarized antenna element corresponding to the second polarization;
• measuring a second signal corresponding to a second polarization via said second feed point of said dual-polarized antenna element and the switch, the switch being set to a second position for receiving the second polarization, wherein the second signal corresponds to the electromagnetic waves transmitted using the second beam and subsequently reflected from at least one obstruction towards said dual-polarized antenna element;
• performing proximity detection based on the measured first and second signals;
• and
• causing adjusting transmit power of the beamforming device based on results of the proximity detection.