Abstract: An electronic device may include a receiver having a light source that provides an optical signal to an optical splitter. An optical combiner may be coupled to the optical splitter over a set of parallel optical paths. A phased antenna array may have a set of antennas disposed on the optical paths. Each antenna may include an optical modulator disposed on a respective one of the optical paths and an antenna resonating element coupled to the modulator. Incident radio-frequency signals may produce electrical signals on the antenna resonating elements. Optical phase shifters may provide optical phase shifts to the optical signal. The modulators may modulate the optical local oscillator signal using the electrical signals. The optical combiner may generate a combined signal by combining modulated optical signals from the optical paths. A demodulator may recover wireless data from the radio-frequency signals using the combined signal.

Abstract: An electronic device may include a fully-connected photonic phased antenna array having a set of antennas, each with an antenna resonating element coupled to a set of photodiodes. Optical modulators may receive different wireless data streams and may generate modulated signals. Optical paths may provide the modulated signals generated by each modulator to a different photodiode in each antenna. Sets of optical phase shifters may apply different sets of phase shifts for each of the modulated signals. Optical paths may provide the phase shifted signals to the photodiodes in the antennas. The photodiodes may produce currents that are superposed on the antenna resonating elements. Each antenna may be used to concurrently convey all of the wireless data streams. The phase shifts may configure the array to transmit signals that include the wireless data streams within different respective signal beams.

Abstract: An electronic device may include an optical demultiplexer, optical combiners, optical paths between the demultiplexer and the combiners, modulators on the optical paths, and a symbol generator that generates a set of electrical OFDM symbols. The modulators may generate a set of optical OFDM symbols by mixing optical carriers with the electrical OFDM symbols. The combiners may generate an aggregate optical OFDM symbol from the optical OFDM symbols and may combine the aggregate optical OFDM symbol with an optical local oscillator signal. The aggregate optical OFDM symbol may exhibit a large bandwidth. The combiners may illuminate a photodiode, which produces current on an antenna resonating element that radiates a radio-frequency signal at frequencies greater than 100 GHz.

Abstract: This application provides an example base station for an example wireless communication network and an example method. One example base station includes a central unit and a remote radio unit (RRU). The RRU includes one or more antennas. The RRU is coupled to the central unit via one or more optical transmission fibers. Each optical transmission fiber defines a respective downlink transmission channel for transmitting a respective downlink transmission signal from the central unit to the respective antenna of the RRU. The RRU is configured to provide a respective uplink feedback signal based on the respective downlink transmission signal via an uplink feedback channel to the central unit.

Abstract: An electronic device may include wireless circuitry that conveys radio-frequency signals at frequencies greater than or equal to 100 GHz using first and second optical local oscillator (LO) signals generated by clocking circuitry. The clocking circuitry may include a first laser that generates the first optical LO signal and a second laser that generates the second optical LO signal. First and second self-injection locking loop paths may be coupled around the first and second lasers respectively. The first loop path may include a first mixer, an optical reference, and a second mixer. The second loop path may include a photodiode, the first mixer, and the optical reference. The photodiode may provide a radio-frequency signal to the mixers. The optical reference may include an optical delay line or resonator and may reduce phase noise of optical signals used to self-injection lock the first and second lasers.

Abstract: An electronic device may include clocking circuitry with primary and secondary lasers that generate first and second optical local oscillator (LO) signals. A phase-locked loop (PLL) may tune the secondary laser based to phase lock the first and second optical LO signals. A self-injection locking loop path may couple an output of the secondary laser to its input. The self-injection locking loop path may include a first mixer and a second mixer. The first mixer may generate a beat signal using the first and second optical LO signals. The second mixer may generate a self-injection locking signal based on the first optical LO signal and the beat signal. A delay line or optical resonator may iteratively self-inject the self-injection locking signal onto the secondary laser. This may serve to minimize phase noise and jitter of the optical LO signals.

Abstract: An electronic device may include wireless circuitry with light sources, a set of photodiodes, a resonating element, and a common gate amplifier (CGA). In a transmit mode, the photodiodes may use optical local oscillators to generate equal portions of an antenna current amplified by the CGA for transmission by the resonating element. In a receive mode, the resonating element may generate an antenna current which is amplified by the amplifier and passed to the photodiodes. Including multiple photodiodes coupled to the amplifier in a current sharing configuration may serve to boost power. The amplifier may exhibit a wide bandwidth, may perform impedance matching between the resonating element and the photodiodes, and may isolate the photodiodes from antenna mismatch. The antenna may be integrated into a phased antenna array to further boost power.

Abstract: A MIMO system comprises a remote radio unit (RRU) and central unit. The RRU comprises: a binary phase shift keying (BPSK) modulator, configured to modulate a BPSK waveform by a local oscillator (LO) signal to generate a stimulus signal, wherein the LO signal is derived from a downlink optical signal received via downlink radio over fiber (DL-ROF) from a central unit (CU); and an optical signal generator, in particular a laser, configured to generate an uplink optical signal based on the stimulus signal for transmission via uplink radio over fiber (UL-ROF) to the CU.

Abstract: A remote radio unit is for a base transceiver station. The remote radio unit includes: a noise generator configured to provide a RF noise signal having predefined statistical properties; a communication interface configured to transmit the RF noise signal as a stimulus signal over a radio-over-fiber uplink channel between the remote radio unit and a central unit of the base transceiver station for determining a pre-distortion of a target signal to be transmitted by the remote radio unit. The communication interface is further configured to receive the pre-distorted target signal over a ROF downlink channel between the remote radio unit and the central unit of the base transceiver station. The remote radio unit also has an antenna for transmitting the pre-distorted target signal received by the communication interface.

Abstract: This application provides an example base station for an example wireless communication network and an example method. One example base station includes a central unit and a remote radio unit (RRU). The RRU includes one or more antennas. The RRU is coupled to the central unit via one or more optical transmission fibers. Each optical transmission fiber defines a respective downlink transmission channel for transmitting a respective downlink transmission signal from the central unit to the respective antenna of the RRU. The RRU is configured to provide a respective uplink feedback signal based on the respective downlink transmission signal via an uplink feedback channel to the central unit.

Abstract: A MIMO system comprises a remote radio unit (RRU) and central unit. The RRU comprises: a binary phase shift keying (BPSK) modulator, configured to modulate a BPSK waveform by a local oscillator (LO) signal to generate a stimulus signal, wherein the LO signal is derived from a downlink optical signal received via downlink radio over fiber (DL-ROF) from a central unit (CU); and an optical signal generator, in particular a laser, configured to generate an uplink optical signal based on the stimulus signal for transmission via uplink radio over fiber (UL-ROF) to the CU.

Abstract: A remote radio unit is for a base transceiver station. The remote radio unit includes: a noise generator configured to provide a RF noise signal having predefined statistical properties; a communication interface configured to transmit the RF noise signal as a stimulus signal over a radio-over-fiber uplink channel between the remote radio unit and a central unit of the base transceiver station for determining a pre-distortion of a target signal to be transmitted by the remote radio unit. The communication interface is further configured to receive the pre-distorted target signal over a ROF downlink channel between the remote radio unit and the central unit of the base transceiver station. The remote radio unit also has an antenna for transmitting the pre-distorted target signal received by the communication interface.