Abstract: A receiver arranged to receive and to suppress a distortion in a receive signal, the receive signal comprising an information signal, the information signal occupying a first frequency band, the receive signal further comprising a pilot signal, the pilot signal occupying a second frequency band different from the first frequency band, the receiver comprising a pilot removal device arranged to receive a processed receive signal, and to extract and process the processed pilot signal from the processed receive signal as a processed extracted pilot signal, and to combine the processed extracted pilot signal with the processed receive signal to generate a distortion suppressed receive signal.

Abstract: A microwave radio link chain comprising a first transmitter, a first receiver and one or more repeaters between the first transmitter and the first receiver. The one or more repeaters is arranged to receive (signals originally transmitted by the first transmitter and to transmit the received signals in the direction of the first receiver, the microwave radio link chain being characterized in that one or more of said repeaters is arranged to invert the spectrum of the signals before they are transmitted by the repeater. In embodiments, one or more of the repeaters is also arranged to amplify the received signals before they are transmitted.

Abstract: A radio antenna alignment tool (100) for aligning a first antenna with respect to at least a second antenna is disclosed. The tool comprises a sensor unit (120) disposed in connection to the first antenna (110) comprising means to determine a present direction of the first antenna (110). The radio antenna alignment tool (100) further comprises guiding means (130) adapted to receive, on a first input port, the present direction of the first directive antenna (110) from the sensor unit (120). The guiding means (130) is further arranged to indicate to a user at least one of: the present direction of the first directive antenna (110), the location of the second antenna, and a preferred direction of the first directive antenna, where said preferred direction of the first directive antenna is determined in order to maximize a signal quality metric for communication between the first directive antenna and at least the second antenna.

Abstract: A method (400) for positioning a first and a second radio antenna comprising the steps of configuring (SI) the first antenna to have a main lobe L1 and configuring (52) the second antenna to be a directive antenna having a main lobe L2. The method also comprising the steps of transmitting (S3) a first alignment signal from the first antenna to the second antenna and positioning (S4) the second antenna based on the received first alignment signal, as well as reconfiguring (S5) the first antenna to be a directive antenna having an antenna main lobe L3, the antenna main lobe L3 having a more narrow main lobe width than the antenna main lobe L1. The method provides a systematic approach to finding optimum antenna positions and corresponding main lobe directions which is especially suited for aligning directive radio antennas in NLOS communication scenarios.

Abstract: This disclosure is directed to an optical transmitter arrangement 100 and a method therein producing a first RF-signal UA1 comprising a first set of data A1 carried by a subcarrier fC1, and a second RF-signal UB1 comprising a second set of data B1 carried by the subcarrier fC1. Further producing a first transform signal H(UA1) being a Hilbert Transform of the first RF-signal UA1, and a second transform signal ?H(UB1) being a Hilbert Transform of the second RF-signal UB1. In addition, modulating the optical carrier fopt with the first RF-signal UA1 and the first transform signal H(UA1), and forming a first sideband SB1 comprising the first set of data A1 at one side of the frequency f0 of the optical carrier fopt. In addition, modulating the optical carrier fopt with the second RF-signal UB1 and the second transform signal ?H(UB1), and forming a second sideband SB2 comprising the second set of data B1 at the other side of the frequency f0 of the optical carrier fopt.

Abstract: A system for communication over a fiber link is disclosed. The system comprises a transmitter to transmit an information signal that comprises an information spectrum, and to transmit two spectrally inverted copies of the information spectrum over the predefined length of the fiber link, the two spectrally inverted copies corresponding to a first spectrum with a first center wavelength and to a second spectrum with a second center wavelength, the second spectrum being inverted relative to the first spectrum and the second center wavelength being different from the first center wavelength, and a receiver to receive the first spectrum and the second spectrum, and to estimate a phase rotation of the second spectrum relative to the first spectrum by comparing a first phase measured from the first spectrum with a second phase measured from the second spectrum.

Abstract: An electro-optical switch (170) for receiving N data streams optically, each of said N data streams having an amplitude and a phase and each being located at an optical center frequency FO1+RFM, where FO1 is a first optical modulation frequency and RFM is a signal center frequency. The electro-optical switch is arranged to convert the N data streams to electrical data signals at the data stream's signal center frequency RFM, the electrical data signals having the amplitude and phase of the optical data stream. The electro-optical switch is further arranged to convert electrical data signals to optical output signals at optical center frequency FO2+RFOut with the amplitude and phase of the first electrical data signal maintained, and to transmit the optical output signals, with RFM and RFOut, being equal to or different from each other, and FO1 and FO2 also being equal to or different from each other.

Abstract: The invention relates to an optical spectrum inverter, configured for counteracting phase distortion effects in an optical channel over a predefined frequency range, to an inverter node, configured for duplex operation in at least two wavelength channels, and to a method for counteracting phase distortion effects in an optical channel.

Abstract: The invention relates to a noise compensation system, configured for compensating phase noise in coherent optical communications, and to a method for compensating phase noise.

Abstract: The present disclosure is directed to a transmitter arrangement 200; 400 and a method therein for transmitting a signal OB comprising a number of data streams D1, D2, D3, D4 and a number of sub-channels BP1, BP2, BP3, BP4; QP1, QP2; QA1 to a receiver 150 via a transmission link 140. The method comprises the actions of: obtaining link quality information indicative of the transmission conditions for the transmission link 140, and determining the number of sub-channels for the output signal based on obtained the transmission conditions such that the transmitted data throughput via the transmission link 140 remains the same and such that the transmitted data throughput is equally distributed between the determined number of sub-channels.

Abstract: A tunable chirped delay line arrangement (0) configured to operatively propagate a signal and includes a at least one chirped delay line (1) arranged along a reference direction (z) on a dielectric layer (2) arranged on a ground plane (3). The chirped delay line (1) is configured with a smoothly varying width along the reference direction (z), and the arrangement (0) further comprising at least one electronically tunable impedance (5) interconnecting the at least one delay line (1) and the ground plane (3) at at least one location along the reference direction (z) such that the at least one delay line (1) is loaded by the tunable impedance (5).

Abstract: This disclosure relates to an optical receiver arrangement (500) and a method for receiving a multichannel optical signal OB in an optical receiver arrangement (500), wherein the optical signal OB comprises a number of optical channels A, B, C, D equally distributed around an optical carrier frequency fLO and wherein the optical receiver arrangement (500) comprises an optical homodyne receiver (200) and a multichannel recovery unit (300).

Abstract: A modulator for an electrical signal comprises a data input port and a clock frequency input port. The modulator also comprises a first phase shifter for subjecting input clock frequency signals to a phase shift and adapted to keep the phase of an input clock frequency signal aligned with the phase of a data stream which is input at the data input port. The modulator also comprises a first XOR gate with an output port, to which first XOR gate said input ports of the modulator are connected, by means of which a BPSK signal is created at the output port when a first data stream is connected to the data input port and a first clock frequency signal is connected to the clock frequency input port.

Abstract: Method, transmitter, receiver, and system for communicating information carried by a polarization divided optical signal in an optical fiber, comprising: producing and transmitting a polarization divided optical signal OTApol comprising optical sideband pairs SBLA, SBHA each having one sideband SBLA at a first polarization and an other sideband SBHA at a second polarization that is orthogonal to the first polarization, the one sideband and the other sideband carry the same set of information A; and receiving and detecting the polarization divided optical signal OTApol to produce an electrical signal RFApol corresponding to the polarization divided optical signal; down converting the electrical signal to produce, for each sideband pair, a first converted signal BBLA corresponding to the one sideband SBLA and a second converted signal BBHA corresponding to the other sideband SBHA; and extracting the set of information A for each sideband pair using a polarization diversity scheme.

Abstract: An optical communications system (300, 400, 500) comprising a first transmit unit (301, 401, 402) and a first receive unit (302, 401, 402). The first transmit unit comprises an electro-optical modulator (311) for modulating one or more radio channels bearing electrical signals with a total bandwidth B by a laser signal (310) with a laser frequency fL1, and the first transmit unit also comprises a transmit filter for outgoing signals from the electro-optical modulator. The first receive unit comprises an electro-optical demodulator (313) for demodulating the one or more electrical signals received from the first transmit unit by means of a Local Oscillator, LO (312), which produces an optical signal at a second frequency fL2, and B ranges from the lower of fL1 and fL2 to the higher of fL1 and fL2.

Abstract: A communications network transport node comprising an optical add-drop multiplexer (OADM), comprising optical signal processing apparatus, electrical signal routing apparatus, and a packet switch. Each optical signal processing apparatus comprises an optical input, an optical output, optical-to-electrical (O-E) signal conversion apparatus arranged to receive input optical channel signals and to convert each into an input radio frequency (RF) modulated electrical channel signal, and electrical to optical (E-O) signal conversion apparatus arranged to receive output RF modulated electrical channel signals and to convert each into an output optical channel signal. The electrical signal routing apparatus determines which input RF modulated electrical channel signals are to be dropped, and routes these to the electrical drop outputs, and which are to be transmitted, and routes these to a selected E-O apparatus.

Abstract: This disclosure is directed to an optical transmitter arrangement 100 and a method therein producing a first RF-signal UA1 comprising a first set of data A1 carried by a subcarrier fC1, and a second RF-signal UB1 comprising a second set of data B1 carried by the subcarrier fC1. Further producing a first transform signal H(UA1) being a Hilbert Transform of the first RF-signal UA1, and a second transform signal ?H(UB1) being a Hilbert Transform of the second RF-signal UB1. In addition, modulating the optical carrier fopt with the first RF-signal UA1 and the first transform signal H(UA1), and forming a first sideband SB1 comprising the first set of data A1 at one side of the frequency f0 of the optical carrier fopt. In addition, modulating the optical carrier fopt with the second RF-signal UB1 and the second transform signal ?H(UB1), and forming a second sideband SB2 comprising the second set of data B1 at the other side of the frequency f0 of the optical carrier fopt.

Abstract: The invention relates to a method for controlling rotation speed of at least one rotary element in the drive line of a vehicle. A first control model and a second control model are defined. The first control model calculates a permitted slip of at least one of the ground engagement elements of the vehicle at its ground contact point, which ground engagement element is driven via the rotary element. The second control model calculates a torque to said ground engagement element. The result of one of said control models is used for controlling the rotation speed of the rotary element.

Abstract: An electro-optical switch (170) for receiving N data streams optically, each of said N data streams having an amplitude and a phase and each being located at an optical centre frequency FO1+RFM, where FO1 is a first optical modulation frequency and RFM is a signal centre frequency. The electro-optical switch is arranged to convert the N data streams to electrical data signals at the data stream's signal centre frequency RFM, the electrical data signals having the amplitude and phase of the optical data stream. The electro-optical switch is further arranged to convert electrical data signals to optical output signals at optical centre frequency FO2+RFOut with the amplitude and phase of the first electrical data signal maintained, and to transmit the optical output signals, with RFM and RFOut, being equal to or different from each other, and FO1 and FO2 also being equal to or different from each other.

Abstract: An optical communications system (300, 400, 500) comprising a first transmit unit (301, 401, 402) and a first receive unit (302, 401, 402). The first transmit unit comprises an electro-optical modulator (311) for modulating one or more radio channels bearing electrical signals with a total bandwidth B by a laser signal (310) with a laser frequency fL1, and the first transmit unit also comprises a transmit filter for outgoing signals from the electro-optical modulator. The first receive unit comprises an electro-optical demodulator (313) for demodulating the one or more electrical signals received from the first transmit unit by means of a Local Oscillator, LO (312), which produces an optical signal at a second frequency fL2, and B ranges from the lower of fL1 and fL2 to the higher of fL1 and fL2.