A method of RF signal processing comprises receiving an incoming RF signal at each of a plurality of antenna elements that are arranged in a first pattern. The received RF signals from each of the plurality of antenna elements are modulated onto an optical carrier to generate a plurality of modulated signals that each have at least one sideband. The modulated signals are directed along a corresponding plurality of optical channels with outputs arranged in a second pattern corresponding to the first pattern. A composite optical signal is formed using light emanating from the outputs of the plurality of optical channels. Non-spatial information contained in at least one of the received RF signals is extracted from the composite signal.

A transmitter for communication-less bistatic ranging includes a photon emitter configured to emit a plurality of photons at particular times in a pointing direction, and a processor configured to identify a particular sub-code of a plurality of sub-codes based on a dynamic state of the transmitter, each one of the plurality of sub-codes including a portion of a long optimal ranging code, generate a plurality of encoded pulse timings by dithering pulse timings from a nominal repetition frequency based on the particular sub-code, and control the photon emitter to emit the plurality of photons at the plurality of encoded pulse timings.

A receiver (12) includes at least a spatial light modulation unit (12a), splitters (12b to 12d), a spatial filtering unit (12h), and a wavefront measurement unit (12i). The splitters (12b to 12d) transmit and reflect reference signal light of a reference optical frequency received via space (15) after being transmitted from a transmitter 11. The spatial filtering unit (12h) extracts a plane wave component, which is a signal component other than distortions, from the reflected light and outputs the extracted light as reference light. The wavefront measurement unit (12i) measures a wavefront due to the interference between the reference light and the reflected and transmitted signal light to detect a wavefront distortion of the reference signal light. The spatial light modulation unit (12a) wavefront-modulates the reference signal light received from the transmitter (11) into a plane wave without wavefront distortions with a reversed wavefront distortion obtained by reversing the detected wavefront distortion. That is, the wavefront modulation corrects the reference signal light into a plane wave without wavefront distortions.

A receiver (12) includes at least a spatial light modulation unit (12a), splitters (12b to 12d), a spatial filtering unit (12h), and a wavefront measurement unit (12i). The splitters (12b to 12d) transmit and reflect reference signal light of a reference optical frequency received via space (15) after being transmitted from a transmitter 11. The spatial filtering unit (12h) extracts a plane wave component, which is a signal component other than distortions, from the reflected light and outputs the extracted light as reference light. The wavefront measurement unit (12i) measures a wavefront due to the interference between the reference light and the reflected and transmitted signal light to detect a wavefront distortion of the reference signal light. The spatial light modulation unit (12a) wavefront-modulates the reference signal light received from the transmitter (11) into a plane wave without wavefront distortions with a reversed wavefront distortion obtained by reversing the detected wavefront distortion. That is, the wavefront modulation corrects the reference signal light into a plane wave without wavefront distortions.

A pointing unit 102 is for use with a free space optical communications terminal 100 including an optical source 104. The pointing unit 102 includes a first portion 106 having a mirrored surface 108, the first portion 106 being orientatable relative to an optical beam 110 produced by the optical source 104 and incident on the mirrored surface 108 in use to direct a reflection 112 of the optical beam 110 from the mirrored surface 108 towards a target 107. The first portion 106 further includes a directional radio frequency antenna 114.

A pointing unit 102 is for use with a free space optical communications terminal 100 including an optical source 104. The pointing unit 102 includes a first portion 106 having a mirrored surface 108, the first portion 106 being orientatable relative to an optical beam 110 produced by the optical source 104 and incident on the mirrored surface 108 in use to direct a reflection 112 of the optical beam 110 from the mirrored surface 108 towards a target 107. The first portion 106 further includes a directional radio frequency antenna 114.

In order to provide a spatial optical transmission apparatus capable of transmission and reception on one optical axis in common between transmission and reception, the optical transmission apparatus includes: an optical circulator configured to output an optical signal input to a first port from a second port, and output an optical signal input to the second port from a third port; a light projecting movable lens positionally adjustable in a plane substantially perpendicular to an optical axis of an optical signal passing through the second port; a light receiving movable lens positionally adjustable in a plane substantially perpendicular to an optical axis of an optical signal passing through the third port; a spectroscope configured to split an optical signal having passed through the light receiving movable lens to transmitted light and reflected light; a position sensor configured to detect a position of an optical axis using either one of the transmitted light or reflected light from the spectroscope; and a control unit configured to perform position adjustment of the light receiving movable lens and/or the light projecting movable lens on the basis of the optical axis position detected by the position sensor, and control optical axis adjustment so that the other of the transmitted light or reflected light from the spectroscope is appropriately incident on the reception optical fiber cable.

In order to provide a spatial optical transmission apparatus capable of transmission and reception on one optical axis in common between transmission and reception, the optical transmission apparatus includes: an optical circulator configured to output an optical signal input to a first port from a second port, and output an optical signal input to the second port from a third port; a light projecting movable lens positionally adjustable in a plane substantially perpendicular to an optical axis of an optical signal passing through the second port; a light receiving movable lens positionally adjustable in a plane substantially perpendicular to an optical axis of an optical signal passing through the third port; a spectroscope configured to split an optical signal having passed through the light receiving movable lens to transmitted light and reflected light; a position sensor configured to detect a position of an optical axis using either one of the transmitted light or reflected light from the spectroscope; and a control unit configured to perform position adjustment of the light receiving movable lens and/or the light projecting movable lens on the basis of the optical axis position detected by the position sensor, and control optical axis adjustment so that the other of the transmitted light or reflected light from the spectroscope is appropriately incident on the reception optical fiber cable.

A free-space optical communication method is provided. The method includes generating, at a transmitter of a satellite, an optical frequency comb and a pump signal, modulating the optical frequency comb to generate a data signal and an idler signal that is a phase conjugate of the data signal, attenuating the pump signal, transmitting over free-space, from the satellite, a communication signal having the data signal, the idler signal and the pump signal, receiving from the satellite, at a receiver, the transmitted communication signal having the data signal, the idler signal, and the attenuated pump signal, amplifying, at a phase-sensitive amplifier, the data signal and the idler signal, and demodulating the data signal and the idler signal to extract data.

Provided are a method of bandwidth allocation for transmitting mobile data and a network device. The bandwidth allocation method includes receiving a cooperative transport interface (CTI) message including a traffic pattern corresponding to a CTI pattern identification (ID) from a distributed unit (DU) of a mobile network, and allocating a bandwidth for transmitting mobile data based on the traffic pattern included in the CTI message.