Abstract: Method and multi carrier receiver for removing interference from a RF-signal. In a multi carrier receiver with a heterodyne receiver structure, the RF-signal is received from a multi carrier transmitting entity. The RF-signal comprises a data part an interference part. The interference part is detected by means of the interference unit, and a frequency and a power level of the interference part is determined. A frequency of a first LO is adjusted, such that an output signal of a first mixer is frequency shifted towards an upper edge or a lower edge of a first IF bandpass filter when the determined power level exceeds a predetermined threshold. By detecting an interference part of an incoming RF-signal and controlling a local oscillator based on the detected interference, an effective and flexible solution is achieved for removing interference from the RF-signal.

Abstract: Method and apparatus for antenna calibration have been disclosed. A radio unit (510) is provided. The radio unit (510) may comprise: a plurality of transmit/receive (TX/RX) paths; a plurality of radio frequency (RF) ports (512) connected with the plurality of TX/RX paths; and a coupling unit (516), coupled with the plurality of TX/RX paths and configured to inject an uplink (UL) calibration signal (550) into at least one of the plurality of TX/RX paths and extract a downlink (DL) calibration signal (540) from at least one of the plurality of TX/RX paths. A normal TX/RX path may be reused both for antenna calibration and antenna supervision. Thus, a low cost hardware solution for antenna calibration is provided. An AIR base station (500) comprising such radio unit (510) is also provided.

Abstract: An apparatus for facilitating antenna calibration comprising: a directional coupler having first, second, third and fourth ports, the first port selectively connected to a radio transmitter or a radio receiver and the second port connected to an antenna; a power combiner/divider having first, second and third ports; the first port of the power combiner/divider selectively connected to a measurement receiver or a measurement transmitter and the second port of the power combiner/divider connected to the third port of the direction coupler; and a magnitude and phase adjustor connected between the fourth port of the directional coupler and the third port of the power combiner/divider. The magnitude and phase adjustor is configured to be tuned such that any signal input to the second port of the directional coupler results in an output smaller than a predetermined threshold at the first port of the power combiner/divider.

Abstract: In a method of a heterodyne FDD receiver for enabling reception of a multi-band RXRF signal spectrum, an RXRF signal spectrum is received, which comprises a lower frequency band and a higher frequency band. A Local Oscillator, LO, output frequency, fLO, is selected based on a frequency fA of the lower frequency band, and a frequency fB of the higher frequency band. Moreover, the RXRF signal spectrum is frequency shifted into an RXIF signal spectrum, by mixing the RXRF signal spectrum with the LO output frequency fLO. The LO frequency fLO is selected to satisfy fA<fLO<fB, where fA and fB are any frequency of the lower or higher frequency band, respectively, such that when mixing the RXRF signal spectrum, one of the lower frequency band and the higher frequency band is frequency shifted into a first frequency band of the RXIF signal spectrum, and one another of the lower frequency band and the higher frequency band is frequency shifted folded into a second frequency band of the RXIF signal spectrum.

Abstract: The present disclosure provides an apparatus and a method for canceling inter-modulation (IM) products in a transceiver. The apparatus includes: a pre-distortion circuit configured to estimate a first IM product caused by a transmission signal and pre-distort the transmission signal to cancel the first IM product; an IM product calculator configured to calculate a second IM product caused by the transmission signal in a received signal based on the first IM product; and a subtractor configured to subtract the second IM product from the received signal.

Abstract: Embodiments provides a radio network entity and the method thereof for improving filtering performance in a time division duplexing radio communication system, the radio network entity comprises: a first filter, which is configured to perform a first type of filtering for a signal to be transmitted to, or received from a device in the radio communication system through a radio interface, with a common filtering requirement for transmitting and receiving fulfilled, a second filter, which is configured to perform a second type of filtering for the signal to be transmitted to the device, with additional filtering requirement for transmitting besides the common filtering requirement fulfilled; and a third filter, which is configured to perform a third type of filtering for the signal received from the device, with additional filtering requirement for receiving besides the common filtering requirement fulfilled.

Abstract: In a method in a common observation receiver of a transceiver, a Transmitter Radio Frequency, TXRF, signal spectrum is received, a Receiver Radio Frequency, RXRF, signal spectrum is further received. Furthermore, a switching scheme is determined based on whether the type of the transmitter and the receiver is Frequency Division Duplex, FDD, or Time Division Duplex, TDD. Based on the switching scheme, the TXRF signal spectrum and the RXRF signal spectrum are switched into a switched baseband signal spectrum. By arranging a common observation receiver in a radio transceiver, and observing radio frequency signal spectrums, the transceiver may acquire knowledge about nonlinearities and other irregularities of applied components.

Abstract: Method and transceiver arrangements for reducing a leakage signal's impact on a receiver part 320 of the transceiver arrangement 300. The leakage signal originates from a transmitter part 310 of the transceiver arrangement 300. The radio base station is adapted to communicate in a Time Division Duplex, TDD mode in a cellular network. The method comprises frequency shifting 402, by the transmitter part 310, a downlink, DL, base-band by an offset frequency, fc, the DL baseband comprising DL data. Furthermore, the method comprises to mixing 404, by the transmitter part (310), the frequency shifted DL baseband with a Transmitter Local Oscillator, TX LO, frequency, fLO to produce a DL signal spectrum.

Abstract: The present invention relates to a method for controlling performance in a radio base station communicating in a Time Division Duplex (TDD) mode in a cellular network. The radio base station has a transceiver comprising a transmitter part, a receiver part, and an antenna, the antenna being alternately connectable to the transmitter part and the receiver part. The method comprises: estimating, at the receiver part, a leakage signal in the receiver part, the leakage signal originating from a local oscillator of the transmitter part; and removing, at the receiver part, the estimated leakage signal from a received uplink signal. The present invention also relates to a corresponding radio base station.

Abstract: A method in a base station is provided for reducing distortion of an uplink signal received in a receiver part (20) of the base station, said distortion being caused by intermodulation, IM, products. The method comprises: generating (106), from a transmitter source signal, a modeled signal of IM components, as nth order IM components of the transmitter source signal, n being an integer value of 2, 3, 4 and/or 5 etc., and detecting (110) IM products of the received uplink signal, the received uplink signal comprising UL traffic components and the IM products, by correlating the received uplink signal with the IM components of the modeled signal. The method further comprises producing (112) a cancellation signal based on the detected IM products of the received uplink signal, and subtracting (114) the cancellation signal from the received uplink signal. Also, a similar apparatus in a base station is provided.

Abstract: Controlling performance in a Time Division Duplex (TDD) radio node is provided. The TDD radio node having multiple parallel branches and antennas for radio transmission of signals propagating through a transmit chain in each of the branches before emission from the antennas. A signal generator generates a signal that propagates through each branch. A signal tapper taps the signal from each of the branches after the transmit chain. A control unit determines a timing of the tapped signal from each of the branches, and monitors timing alignment of the branches based on the determined timing of tapped signals. If it is discovered that there is a timing misalignment between the branches that exceeds a preset acceptable limit, a transmission delay can be adjusted for at least one of the branches to reduce the misalignment.

Abstract: Method and multi carrier receiver for removing interference from a RF-signal. In a multi carrier receiver with a heterodyne receiver structure, the RF-signal is received from a multi carrier transmitting entity. The RF-signal comprises a data part an interference part. The interference part is detected by means of the interference unit, and a frequency and a power level of the interference part is determined. A frequency of a first LO is adjusted, such that an output signal of a first mixer is frequency shifted towards an upper edge or a lower edge of a first IF bandpass filter when the determined power level exceeds a predetermined threshold. By detecting an interference part of an incoming RF-signal and controlling a local oscillator based on the detected interference, an effective and flexible solution is achieved for removing interference from the RF-signal.

Abstract: The present disclosure provides an apparatus and a method for canceling inter-modulation (IM) products in a transceiver. The apparatus includes: a pre-distortion circuit configured to estimate a first IM product caused by a transmission signal and pre-distort the transmission signal to cancel the first IM product; an IM product calculator configured to calculate a second IM product caused by the transmission signal in a received signal based on the first IM product; and a subtractor configured to subtract the second IM product from the received signal.

Abstract: Method and apparatus for antenna calibration have been disclosed. A radio unit (510) is provided. The radio unit (510) may comprise: a plurality of transmit/receive (TX/RX) paths; a plurality of radio frequency (RF) ports (512) connected with the plurality of TX/RX paths; and a coupling unit (516), coupled with the plurality of TX/RX paths and configured to inject an uplink (UL) calibration signal (550) into at least one of the plurality of TX/RX paths and extract a downlink (DL) calibration signal (540) from at least one of the plurality of TX/RX paths. A normal TX/RX path may be reused both for antenna calibration and antenna supervision. Thus, a low cost hardware solution for antenna calibration is provided. An AIR base station (500) comprising such radio unit (510) is also provided.

Abstract: A method in a first network node (105) for estimating a first timing offset difference between a first timing offset of a first base station and a second timing offset of a second base station, is provided. The first network node (105) receives Uplink Time Difference Of Arrival, UTDOA, measurements. The UTDOA measurements relate to a first UTDOA time difference. The first network node (105) further receives Observed Time Difference Of Arrival, OTDOA, measurements. The OTDOA measurements relate to a first measured OTDOA time difference. The first network node estimates a first timing offset difference between a first timing offset of the first base station and a second timing offset of the second base station based on the first UTDOA time difference and the first measured OTDOA time difference.

Abstract: A base station subsystem (1000), a TMA part (100) and a RBS part (150) of a communication system employing TDD; and respective methods are provided for synchronizing the RBS part of the base station subsystem (1000) with the TMA part (100) The RBS part (150) comprises an RBS modem (160) adapted to generate a switch signal comprising a switch command word, and to further send the switch signal to a TMA modem (110). The TMA modem (110) is adapted to demodulate the switch signal and to compare the switch command word with switch command words stored in a register. When any of the switch command words in the register (111) matches the switch command word of the demodulated switch signal, the TMA modem (110) is configured to generate a control signal for controlling a switch of the TMA part for synchronizing the RBS part (150) with the TMA part.

Abstract: The present invention relates to a method and a device for time synchronization of an RBS which has lost its GPS signal. The method in the time synchronization device comprises retrieving from the first radio base station a first timing advance value (710) used by the user equipment to adjust its transmission timing before the handover, and a measurement of a reception timing (720) of a random access preamble. The random access preamble is transmitted from the user equipment to the second radio base station during synchronization. The method also comprises retrieving (730) from the second radio base station a second timing advance value used by the user equipment to adjust its transmission timing after the handover, and determining (740) a time synchronization offset between the first and second radio base station based on the retrieved first timing advance value, the second timing advance value, and the measurement of the reception timing.

Abstract: A Calibration Coupling Unit, CCU, and a method therein for enabling calibration of a Base Station are provided. The CCU comprises an Antenna Interface Standards Group, AISG, interface and the CCU is connected to the Base Station by means of radio branch feeder cables carrying uplink and downlink transmissions to/from the Base Station. The Base Station comprises a Radio Unit, RU, and a Base Band Unit, BBU, and the CCU is further connectable to an antenna array comprising antenna elements. The method in the CCU comprises receiving (110) at least one calibration signal from the RU on at least one radio branch feeder cable of the CCU; and converting (130) the calibration signal to a receiving frequency band of the RU. The method further comprises providing (140) the converted signal to the RU via at least one of the radio branch feeder cables, thereby enabling calibration of the Base Station.

Abstract: A method in a base station is provided for reducing distortion of an uplink signal received in a receiver part (20) of the base station, said distortion being caused by intermodulation, IM, products. The method comprises: generating (106), from a transmitter source signal, a modeled signal of IM components, as nth order IM components of the transmitter source signal, n being an integer value of 2, 3, 4 and/or 5 etc., and detecting (110) IM products of the received uplink signal, the received uplink signal comprising UL traffic components and the IM products, by correlating the received uplink signal with the IM components of the modeled signal. The method further comprises producing (112) a cancellation signal based on the detected IM products of the received uplink signal, and subtracting (114) the cancellation signal from the received uplink signal. Also, a similar apparatus in a base station is provided.

Abstract: In a transmission scheme for transmitting data over a connection connecting a transmitting Main Unit and a receiving Radio Unit of a cellular radio system, where the transmitted data corresponds to user-plane data in the form of digital baseband data for different antenna-carriers, the digital signal is transmitted over the connection, e.g. a fiber, before spreading and combining is provided. The power and weight factor is transmitted separately with a few additional bits. Hereby, the Digital signal before spreading and combining is transmitted in the fiber instead of the combined multi-code signal.