Proposed is a receiving UE for receiving a signal in optical wireless communication, according to the present disclosure. The receiving UE may include: a transceiver for receiving an optical signal of an orbital angular momentum (OAM) mode from a transmitting terminal; a demodulator composed of at least one phase shifter; a photoelectricity converter composed of at least one photodiode; and a processor connected to the transceiver, the demodulator, and the photoelectricity converter. In addition, the at least one phase shifter may convert an optical signal of the OAM mode into an optical signal of a Gaussian mode, and the at least one photodiode may convert an optical signal of the Gaussian mode into an electrical signal.

Spatial division multiplexing (SDM) allows multiple optical signals to be multiplexed onto a single optical link. Performance of SDM systems may be improved by monitoring performance metrics indicative of crosstalk between the spatially multiplexed signals and adjusting at least one transmission characteristic of one or more of the multiplexed signals in order to reduce the impact of the intermodal crosstalk.

Systems and methods for orbital angular momentum (OAM)-based multidimensional signaling with multiple-input-multiple-output (MIMO). The wireless communication is achieved using a transmitter including a plurality of orthogonal pulse shapers of a multidimensional modulator, the plurality of orthogonal pulse shapers generating a multidimensional modulated signal by imposing one or more data sequences on corresponding mutually orthogonal filter impulse responses derived from multiple orthogonal basis functions including Slepian sequences. An OAM antenna array including OAM antenna elements is used such that each of the OAM antenna elements includes an azimuthal phase shifter for shifting an azimuthal phase term of a wavefront generated by an antenna element such that the OAM antenna elements impose the multidimensional modulated signal on pre-determined OAM modes of a carrier signal corresponding to the azimuthal phase term.

A system for enabling signal penetration into a building includes a first transceiver, located on an outside of the building, for transmitting and receiving signals at a first frequency outside of the building, wherein the signals at the first frequency do not easily penetrate into an interior of the building. A first up/down converter converts between a first version of the signals at the first frequency and a second version of the signals at a second frequency. The first frequency is higher than the second frequency and the signals at the second frequency better penetrate to the interior of the building and overcome losses caused by penetrating into an interior of the building. A second up/down converter converts between the second version of the signals at the second frequency that overcomes the losses caused by penetrating into the interior of the building and a third version of the signals after transmission from the building exterior to the building interior. A router transmits and receives the third version of the signals within the interior of the building.

A method and apparatus for transmitting and receiving signals in a wireless communication system, according to an embodiment of the present invention, may comprise a feature of applying a phase pattern to a wavefront of an optical signal and a feature of transmitting the optical signal. The phase pattern may be determined on the basis of an optical phase shift characteristic of a phase mask, and the phase mask may be determined on the basis of a quantization order and a phase order.

A communications system includes a maximum ratio combining (MRC) circuit for receiving a plurality of data streams and processing the plurality of input data streams using maximum ration combining to improve signal to noise ratio. A MIMO transmitter transmits the MRC processed plurality of data streams over a plurality of separate communications links from the MIMO transmitter. Each of the plurality of separate communications links from one transmitting antenna of a plurality of transmitting antennas to each of a plurality of receiving antennas at a MIMO receiver. The MIMO transmitter transmits the MRC processed plurality of data streams using a channel matrix of an impulse response of a channel. The channel matrix is created using a pilot signal transmitted on a pilot channel.

A system for enabling signal penetration into a building comprising a receiver located on an outside of the building for receiving millimeter wave signals. At least one frequency downconverter for downconverts the received millimeter wave signals to a frequency level that overcomes losses occurring when the millimeter wave signals are transmitted from the outside the building to an interior of the building. Transceiver circuitry transmits the downconverted millimeter wave signals from the outside the building to the interior of the building. At least one frequency upconverter upconverts the received downconverted millimeter wave signals from the frequency level that overcomes losses occurring when the millimeter wave signals are transmitted from the outside the building to the interior of the building. A second transceiver transmits the upconverted millimeter wave signal in a second format to wireless devices within the building.

A method for transmitting a plurality of input streams from a transmitter to a receiver processes each of a plurality of input data streams to generate a plurality of parallel pairs of data streams including an in-phase stream (I) and a quadrature-phase stream (Q) for each of the plurality of input data streams. Each of the plurality of parallel pairs of data streams are modulated with a selected one of at least three prolate spheroidal wave functions, respectively, to generate a plurality of data signals, each of the plurality of data signals associated with one of the plurality of parallel pairs of data streams. A plurality of composite data streams are generated by overlaying at least one data signal of the plurality of data signals in a first data layer with the at least one data signal of the plurality of data signals in a second data layer. The plurality of composite data streams are processed to associate with each of the plurality of composite data streams an orthogonal function to cause each of the plurality of composite data streams to be mutually orthogonal to each other on the link to enable transmission of each of the plurality of the composite data streams on the link at a same time.

A system for enabling signal penetration into a building includes a first transceiver, located on an outside of the building, for transmitting and receiving signals at a first frequency outside of the building, wherein the signals at the first frequency do not easily penetrate into an interior of the building. A first up/down converter converts between a first version of the signals at the first frequency and a second version of the signals at a second frequency. The first frequency is higher than the second frequency and the signals at the second frequency better penetrate to the interior of the building and overcome losses caused by penetrating into an interior of the building. A second up/down converter converts between the second version of the signals at the second frequency that overcomes the losses caused by penetrating into the interior of the building and a third version of the signals after transmission from the building exterior to the building interior. A router transmits and receives the third version of the signals within the interior of the building.

A system for providing underwater communication using orbital angular momentum (OAM) includes a transmitter that processes input data to be transmitted using pre-coding information based on current transmission channel conditions to maximize data rate based on channel conditions. A receiver receives a transmitted multiplexed OAM optical signal and analyzes the received signal for channel state information. The channel state information is used to determine a set of pre-coding values that allow the transmitter to pre-code the input data to maximize the data rate based on current channel conditions. The pre-coding values are mapped to a codebook entry which identifies the pre-coding values. The codebook entry is transmitted from the receiver to the transmitter. The transmitter uses the received codebook entry to identify pre-coding values used to process subsequent input data to be transmitted in order to enhance data rate across the transmit channel.