Certain aspects provide a method for radar detection by an apparatus. The method including transmitting a radar waveform in transmission time intervals (TTIs) to perform detection of a target object. The method further includes varying the radar waveform across TTIs based on one or more radar transmission parameters.

A method for transmitting data carrying optical information over an optical channel, comprising the steps of providing an optical transmitter consisting of a light source being a Mode-Locked Optical Frequency Comb (MLFC) for generating a frequency comb of multiple carriers, each of which being modulated by a baseband signal; an optical modulator for modulating each and all of the multiple carriers in a modulation bandwidth extending up to the modes' frequency spacing between the multiple carriers; performing all-optical encoding of the modulated carriers by manipulating the optical amplitude and/or phase and/or polarization of all optically modulated carriers; and transmitting, by the optical transmitter, the encoded modulated carriers to an optical receiver, over an optical channel

A first communication device for use in a wireless communication system to communicate with a second communication device comprises circuitry configured to perform beamforming training with the second communication device to train a plurality of antenna beam combinations of antenna beams used by the first and second communication devices for transmitting and/or receiving signals, select one or more of the trained antenna beam combinations according to a security criterion that is directed to reducing the probability that a third communication device can eavesdrop on the communication between the first communication device and the second communication device, and communicate with the second communication device using the selected one or more antenna beam combinations.

A first communication device for use in a wireless communication system to communicate with a second communication device comprises circuitry configured to perform beamforming training with the second communication device to train a plurality of antenna beam combinations of antenna beams used by the first and second communication devices for transmitting and/or receiving signals, select one or more of the trained antenna beam combinations according to a security criterion that is directed to reducing the probability that a third communication device can eavesdrop on the communication between the first communication device and the second communication device, and communicate with the second communication device using the selected one or more antenna beam combinations.

A communication apparatus includes a reference signal generating section, a transmitting section, a propagation estimating section, a first data acquiring section, and a decoding section. The reference signal generating section generates a first reference signal to enable a communicating party to estimate a propagation environment. The transmitting section transmits the first reference signal. The propagation estimating section estimates a first propagation estimation value of the propagation environment using a second reference signal transmitted from the communicating party. The first data acquiring section generates first data using the first propagation estimation value. The decoding section decodes a transmission signal encoded using a second propagation estimation value that is estimated by the communicating party using the first reference signal, to obtain second data using the first data.

A method for transmitting data carrying optical information over an optical channel, comprising the steps of providing an optical transmitter consisting of a light source being a Mode-Locked Optical Frequency Comb (MLFC) for generating a frequency comb of multiple carriers, each of which being modulated by a baseband signal; an optical modulator for modulating each and all of the multiple carriers in a modulation bandwidth extending up to the modes' frequency spacing between the multiple carriers; performing all-optical encoding of the modulated carriers by manipulating the optical amplitude and/or phase and/or polarization of all optically modulated carriers; and transmitting, by the optical transmitter, the encoded modulated carriers to an optical receiver, over an optical channel.

Encoding element (100) at least selectively transparent to an infrared or ultraviolet light radiation, incident thereon on a first incidence surface (101), wherein—in the volume defined by said encoding element (100)—a plurality of areas (104) is provided, previously selected and arranged according to a predefined pattern wherein at least one polarisation characteristic of the optical radiation (200) that is incident thereon is varied, wherein the variation of said polarisation characteristic of said incident radiation is varied according to a localised alteration pattern biunivocally associated to a predefined ciphering key, and wherein said plurality of areas is arranged between said first incidence surface (101) on which said infrared or ultraviolet light radiation is incident in use, and a second output surface (102) of said infrared or ultraviolet light optical radiation.

Encoding element (100) at least selectively transparent to an infrared or ultraviolet light radiation, incident thereon on a first incidence surface (101), wherein—in the volume defined by said encoding element (100)—a plurality of areas (104) is provided, previously selected and arranged according to a predefined pattern wherein at least one polarisation characteristic of the optical radiation (200) that is incident thereon is varied, wherein the variation of said polarisation characteristic of said incident radiation is varied according to a localised alteration pattern biunivocally associated to a predefined ciphering key, and wherein said plurality of areas is arranged between said first incidence surface (101) on which said infrared or ultraviolet light radiation is incident in use, and a second output surface (102) of said infrared or ultraviolet light optical radiation.

Provided is a polarization decomposition device. The polarization decomposition device includes a polarization beam splitter configured to split an optical signal into a first polarized light having a first polarization direction and a second polarized light having a second polarization direction different from the first polarized light, a phase shifter configured to delay a phase of the first polarized light, a polarization rotator configured to rotate the second polarized light so that the polarization direction of the second polarized light is changed, and an interference beam splitter configured to allow the first polarized light in which the phase is delayed and the second polarized light in which the polarization direction is rotated to interfere with each other and split them into a third polarized light and a fourth polarized light.

Provided is a polarization decomposition device. The polarization decomposition device includes a polarization beam splitter configured to split an optical signal into a first polarized light having a first polarization direction and a second polarized light having a second polarization direction different from the first polarized light, a phase shifter configured to delay a phase of the first polarized light, a polarization rotator configured to rotate the second polarized light so that the polarization direction of the second polarized light is changed, and an interference beam splitter configured to allow the first polarized light in which the phase is delayed and the second polarized light in which the polarization direction is rotated to interfere with each other and split them into a third polarized light and a fourth polarized light.