Abstract: A wireless transmission method includes obtaining an MCS (modulation and coding scheme) rate and a power amplifier gain of each station in a set of stations for a multi-user (MU) transmission, generating a maximum available MCS rate according to a plurality of MCS rates of the set of stations, selecting a power amplifier gain of the MU transmission according to the maximum available MCS rate, adjusting a digital gain of each station according to the power amplifier gain of the MU transmission and the power amplifier gain of each station, adjusting a frequency domain signal of each station according to the digital gain thereof, converting a plurality of adjusted frequency domain signals of the set of stations into a time domain signal, and generating an amplified signal for the MU transmission according to the power amplifier gain of the MU transmission and the time-domain signal.

Abstract: Disclosed embodiments provide flexible performance, high dynamic range, microelectromechanical (MEMS) multipath digital microphones, which allow seamless, low latency transitions between audio signal paths without audible artifacts over interruptions in the audio output signal. Disclosed embodiments facilitate performance and power saving mode transitions maintaining high dynamic range capability.

Abstract: A signal generation unit 2, a DA converter 3, variable attenuators 40, 42, 44, and 46, a measurement unit 6 that detects a level of the signal attenuated by the variable attenuators 40, 42, 44, and 46 and passed through one or more semiconductor components, a switch 48 that switches between an Internal path through which the signal attenuated by the variable attenuator 40, 42, 44, and 46 is transmitted to the measurement unit 6 and an External path through which the signal attenuated by the variable attenuator 40, 42, 44, and 46 is output from an output terminal 10, and a control unit 7 that obtains a correction value of an attenuation amount of the variable attenuators 40, 42, and 44 with the Internal path and obtains a correction value of an attenuation amount of the variable attenuator 46 with the External path.

Abstract: Frequency ranges may be converted by an apparatus including a converter configured to shift an original frequency range of an input data signal to a target frequency range, an input band selective filter bank configured to route the input data signal through a bandpass filter of a selected subrange within the target frequency range, the input selective filter bank including a plurality of bandpass filters, each bandpass filter having a corresponding subrange within the target frequency range.

Abstract: Aspects of the subject disclosure may include, for example, obtaining a reference signal, power information regarding the reference signal, and maximum power threshold for the communication device from a base station over a communication network. Further embodiments can include measuring a power of reference signal obtained from the base station resulting in a measure power, and determining a path loss between the base station and the communication device based on the measured power. Additional embodiments can include adjusting the antenna array to generate a coarse power adjustment for the communication device based on the path loss and the maximum power threshold, and providing a transmission signal to the base station according to the coarse power adjustment over the communication network. Other embodiments are disclosed.

Abstract: An antenna unit is configured to transmit and/or receive signals and is connected to transmitting/receiving unit via a signal cable. A control device is configured to adjust signal strength by modifying gain of the control device. A calibration signal is provided by the transmitting/receiving unit and the signal strength of the calibration signal is used to adjust the gain of the control device.

Abstract: An apparatus is disclosed for transmission setting selection. In an example aspect, an apparatus includes a wireless interface device with a communication processor and a radio-frequency front-end. The communication processor is configured to provide a signal. The radio-frequency front-end is coupled to the communication processor and configured to accept the signal. The radio-frequency front-end includes an amplifier configured to amplify the signal based on one or more amplifier settings. The wireless interface device is configured to adjust the one or more amplifier settings responsive to an output power being changed with a gain being unchanged.

Abstract: According to various embodiments, an electronic device in a wireless communication system may include a Power Amplifier (PA) for a first frequency band, a Low Noise Amplifier (LNA) for a second frequency band at least partially overlapping a frequency band which is twice the first frequency band, and an impedance tuner which is in a first impedance state or a second impedance state under the control of the processor. The PA and the impedance tuner may be electrically coupled. A harmonic output level of the PA in the first impedance state may be greater than a harmonic output level of the PA in the second impedance state. The processor may be configured to control the impedance tuner to be in the second impedance state when communication is performed both in the first frequency band and the second frequency band, and control the impedance tuner to be in the first impedance state when communication is performed only in the first frequency band.

Abstract: Systems and methods related to power amplification and power supply control. A power amplification control system can include an interface configured to receive a transceiver control signal from a transceiver. The power amplification control system can include a power amplifier control component configured to generate a power amplifier control signal based on the transceiver control signal from the transceiver and a power supply control component configured to generate a power supply control signal based on the transceiver control signal from the transceiver and to generate the power supply control signal based on a local control signal from the power amplifier control component.

Abstract: A communication circuit includes a first transfer circuit that includes a first transmitter circuit, and a second transfer circuit that includes a second transmitter circuit that can transmit a signal simultaneously with the first transmitter circuit. The second transmitter circuit is configured to be placed in a transmission halt state when transmission power of the second transmitter circuit resulting from being decreased by a predetermined value is lower than or equal to a threshold.

Abstract: A system and method for compensating for attenuation of carrier power by a transmission path.

Abstract: In one example in accordance with the present disclosure, an antenna system is described. The antenna system includes an array of antennas. Each antenna emits electromagnetic waves and is presented with a load that is different from other antennas in the array. The antenna system also includes a control system. The control system includes a single transmitter to sequentially drive antenna sets, a switching device to select, for each activation period in an activation sequence, an antenna set to be driven, and a controller. The controller determines an actual power output of each antenna and generates an adjusted control signal for the single transmitter such that the output of each antenna is controlled to match a target power for that antenna, regardless of a load for the antenna.

Abstract: Disclosed is a system and method for a 24-GHz phased array for indoor smart radar comprising at least 6 horizontally placed antenna elements as a vertically placed 5-element series-fed microstrip patch array. The beam of the phased array can be continuously steered on the H-plane to different directions through a novel vector control array. Each element can adjust the phase and amplitude of the corresponding element of the horizontally placed linear array. The phased array system of the present invention may be fabricated on a single printed circuit board (PCB), and PIN diodes are used to realize beam steering by modulating the decomposed received signal. In order to compensate for the loss of the vector control array and reduce the noise figure, six low noise amplifiers (LNAs) are also used in the array. The present invention has the ability to continuously steer the beam on the H-plane.

Abstract: A directional coupler (2) includes a main line (11), a sub-line (12), a variable terminator (13), and a variable filter circuit (15). The variable terminator (13) is a variable impedance circuit that terminates one end portion of the sub-line (12). The variable filter circuit (15) is connected to the other end portion of the sub-line (12). The variable filter circuit (15) may include a filter, a bypass path, and a switch which is connected to at least one of the filter and the bypass path.

Abstract: A method and electronic device for applying a maximum permissible exposure (MPE) operation on the electronic device. The electronic device includes a plurality of antenna arrays and a processor operably connected to the plurality of antenna arrays. The processor is configured to detect a MPE condition for radio frequency exposure and apply a MPE operation, from among a plurality of MPE operations, to at least one of the plurality of antenna arrays to modify the radio frequency exposure. The MPE operation includes coordination of at least two antenna arrays for signal transmission.

Abstract: A system and method for compensating for attenuation of carrier power by a transmission path.

Abstract: The disclosure relates to a power control circuitry for controlling a radio frequency, RF, transmitter of a network equipment or a user equipment, the power control circuitry comprising: a controller configured to control a power level of an RF signal generated by the RF transmitter for transmission via an antenna arrangement, wherein the power level is controlled based on information about an object within an coverage area of the antenna arrangement.

Abstract: An electronic device of various embodiments can include a broadcast receiving module, a connector including a first pin and a second pin, and a processor, wherein the processor can be configured to: identify, through the first pin, the type of external electronic device connected through the connector; drive the broadcast receiving module in a state in which an external antenna included in an external electronic device and the broadcast receiving module are electrically connected through the first pin when the external electronic device corresponds to a designated electronic device type; receive a broadcast signal from the external antenna by using the broadcast receiving module; and output, through the second pin, an audio signal generated on the basis of at least a part of the broadcast signal to a designated device. Other embodiments are also possible.

Abstract: The present disclosure relates to a communication method and system for converging a 5th-Generation (5G) communication system for supporting higher data rates beyond a 4th-Generation (4G) system with a technology for Internet of Things (IoT). The present disclosure may be applied to intelligent services based on the 5G communication technology and the IoT-related technology, such as smart home, smart building, smart city, smart car, connected car, health care, digital education, smart retail, security and safety services. A method by a first terminal in a wireless communication system is provided. The method includes determining whether to transmit a preamble for an automatic gain control (AGC), determining a slot and at least one symbol in the slot to transmit the preamble for the AGC, in a case in which it is determined to transmit the preamble for the AGC, and transmitting, to a second terminal, the preamble for the AGC in the determined slot and the at least one symbol in the slot.

Abstract: The present disclosure relates to a communication method and system for converging a 5th-Generation (5G) communication system for supporting higher data rates beyond a 4th-Generation (4G) system with a technology for Internet of Things (IoT). The present disclosure may be applied to intelligent services based on the 5G communication technology and the IoT-related technology, such as smart home, smart building, smart city, smart car, connected car, health care, digital education, smart retail, security and safety services. A method by a first terminal in a wireless communication system is provided. The method includes determining whether to transmit a preamble for an automatic gain control (AGC), determining a slot and at least one symbol in the slot to transmit the preamble for the AGC, in a case in which it is determined to transmit the preamble for the AGC, and transmitting, to a second terminal, the preamble for the AGC in the determined slot and the at least one symbol in the slot.

Abstract: An apparatus, method and computer readable medium for special thermal density reduction by antenna thinning. A system comprises N transmit/receive (TX/RX) chains, where each TX/RX chain comprises an RFFE and each RFFE comprises one or more thermal sensors configured to measure heat in the RFFE. An antenna array coupled to the plurality of TX/RX chains. A codebook that comprises a plurality of code words configured to respond to real-time heat measurements from the thermal sensors in each TX/RX chain is configured to switch off selected TX/RX chains to reduce thermal density at the antenna array while maintaining M RFFEs switched on, where M<N and the desired beamforming gain is 10 log 10(M).

Abstract: An electronic device is provided. The electronic device includes an antenna, a transmission path electrically connected to the antenna and including at least one amplifier, a transceiver connected to the transmission path and converting a signal, a feedback path connected between the transmission path and the transceiver, at least one processor connected to the transceiver and communicating with at least one external electronic device by using the transceiver, and a memory connected to the at least one processor. The processor may obtain first information about a first phase and a first magnitude, which are associated with the first frequency, and second information about a second phase and a second magnitude, which are associated with a multiplied frequency of the first frequency, from the transmission signal and the reflection signal using the transceiver, and may determine a state of the electronic device based on the first information and the second information.

Abstract: A semiconductor device includes a semiconductor substrate, a transistor, and a first harmonic termination circuit. The transistor is formed at the semiconductor substrate. The transistor amplifies an input signal supplied to an input end and outputs an amplified signal through an output end. The first harmonic termination circuit attenuates a harmonic component included in the amplified signal. The first harmonic termination circuit is formed at the semiconductor substrate such that one end of the first harmonic termination circuit is connected to the output end of the transistor and the other end of the first harmonic termination circuit is connected to a ground end of the transistor.

Abstract: A method for device-to-device communication comprises providing a first communication device, a second communication device, and a plurality of base stations, measuring a first set of base station channel gains from the first communication device, measuring a second element of data from the second communication device, providing the first set of base station channel gains and the second element of data as inputs to an algorithm, calculating a D2D channel gain from the first set of base station channel gains and the second element of data with the machine learning algorithm, and adjusting at least one parameter based on the calculated D2D channel. A system for controlling device-to-device communication and a method of training a machine learning algorithm are also described.

Abstract: An electronic device includes a foldable housing including a hinge structure, a first housing structure including a first surface facing a first direction and a second surface facing a second direction opposite to the first direction, a second housing structure including a third surface facing a third direction and a fourth surface facing a fourth direction opposite to the third direction, and folded with respect to the first housing structure about the hinge structure, a wireless communication circuitry disposed inside the first housing structure or the second housing structure, a sensor disposed inside the first housing structure or the second housing structure, a grip sensor circuitry disposed outside the first housing structure or the second housing structure, a processor disposed inside the first housing structure or the second housing structure, and a memory operatively connected with the processor.

Abstract: Described herein are systems, architectures, circuits, devices, and methods for a DC-DC converter that dynamically adjusts a supply voltage to a power amplifier based on the number of resource blocks in a signal to be transmitted. The disclosed technologies estimate the number of resource blocks in a signal, generate a signal corresponding to the estimated number of resource blocks, and modify a supply voltage based on the generated signal. These technologies can be used to increase the efficiency of power amplifier systems for cellular signals being transmitted that have fewer resource blocks than is typically assumed (e.g., at least 100 resource blocks).

Abstract: A MIMO transceiver configured for digital pre-distortion may include a first communication chain configured to wirelessly transmit a signal at a first frequency. The first communication chain may include a pre-distorter circuit configured to accept parameters to pre-distort signals prior to transmission. The first communication chain may include a PA configured to amplify the signals of the first communication chain prior to transmission. The MIMO transceiver may include a second communication chain. The second communication chain may be configured to wirelessly receive the signal at the first frequency. The second communication chain may include a converter circuit configured to convert the signal to a baseband frequency. The second communication chain may include a buffer configured to buffer the signal at the baseband frequency. The MIMO transceiver may include a DPD circuit configured to calibrate the parameters based on the buffered signal to compensate for non-linearity in amplification by the PA.

Abstract: A high-yield, tunable radio frequency (RF) filter includes a plurality of process-dependent capacitors and a plurality of non-volatile RF switches. Each of the plurality of process-dependent capacitors is connected to at least one of the plurality of non-volatile RF switches. An auxiliary capacitor in the plurality of process-dependent capacitors is engaged by an ON-state non-volatile RF switch in the plurality of non-volatile RF switches. A primary capacitor in the plurality of process-dependent capacitors is disengaged by an OFF-state non-volatile RF switch in the plurality of non-volatile RF switches. The auxiliary capacitor substitutes for the primary capacitor.

Abstract: A wireless electronic device is provided which comprises a rechargeable power supply and a power capacity indicator unit. The power capacity indicator unit comprises one or more sensors configured to detect that the wireless electronic device is out of a base charger and is in an idle state for a predetermined idle threshold. The one or more sensors are further configured to detect when a power level of the rechargeable power supply is within at least one predetermined power threshold range. The control unit is configured to activate at least one power status indicator corresponding to the at least one predetermined power threshold range when the wireless electronic device is detected to be out of the base charger and in the idle state for the predetermined idle threshold, and the detection of the power level of the rechargeable power supply is within at least one predetermined power threshold range.

Abstract: Techniques are described herein for allocating transmit power between precoding resource groups (PRGs) and/or transmit chains of a user equipment (UE) to reduce the amount of total transmit power that is unused. The UE may determine a set of precoding scaling factors for each PRG to efficiently allocate a total transmit power between the PRGs using a two-stage approach. During a first stage, the UE may determine PRG-specific precoding scaling factors for each PRG associated with an uplink transmission. During a second stage, the UE may determine a residual precoding scaling factor to apply to all the PRGs associated with the uplink transmission and determine overall precoding scaling factors for each PRG. The second stage may be configured to refine the scaling factors determined in the first stage such that at least some of the unused transmit power is allocated to at least one of the PRGs or transmit chains.

Abstract: Apparatus, computer readable media, and methods for enhanced beamforming training in a wireless local area network are disclosed. An apparatus of a access point or station is disclosed. The apparatus including processing circuitry where the processing circuitry is configured to encode an EBRP packet comprising a first portion comprising an indication of a first number of transmit antenna training settings (N-TX), and an indication of a second number of receive training subfields per N-TX settings (N-RX), and a second portion comprising a third number of training subfields. The third number may be less than or equal to N-TX times N-RX. The processing circuitry may be configured to cause the first portion of the EBRP packet to be transmitted and cause the second portion to be transmitted, where two or more of the third number of training subfields are to be transmitted simultaneously using different antennas and orthogonal sequences.

Abstract: Embodiments of this application provide a channel calibration method, where the method includes: obtaining at least two channel sets including a first channel set and a second channel set, where the at least two channel sets are obtained by grouping a plurality of to-be-calibrated channels, each of the at least two channel sets includes a reference channel and at least one to-be-calibrated channel, and the first channel set and the second channel set have an intersection set; determining a compensation value of each to-be-calibrated channel in each of the at least two channel sets; determining an inter-set compensation value between the first channel set and the second channel set; and calibrating the plurality of channels based on the inter-set compensation value and the compensation values of the to-be-calibrated channels. In embodiments of this application, frequency responses of all channels can be kept consistent, thereby improving calibration accuracy.

Abstract: A bias circuit of an amplifying device including amplifying circuits and a bypass circuit responding to a first control signal, includes a first bias circuit, a second bias circuit, and a compensating circuit. The first bias circuit is configured to supply a first base bias voltage to a first amplifying circuit of the amplifying circuits in response to a second control signal. The second bias circuit is configured to supply a second base bias voltage to a second amplifying circuit of the amplifying circuits in response to a third control signal. The compensating circuit is connected to either one or both of the first bias circuit and the second bias circuit, and configured to vary an impedance in response to a fourth control signal, and compensate for either one or both of the first base bias voltage and the second base bias voltage based on the varied impedance.

Abstract: A radio-frequency (RF) switching system for 5G communications and a method of designing it are disclosed. The RF switching system includes a MMMB switching unit and an antenna. The MMMB switching unit includes a 5G-mode multiband switching subunit including a 5G-mode low-frequency (LF)-band switching subunit and a 5G-mode high-frequency (HF)-band switching subunit partitioned from the 5G-mode LF-band switching subunit at a reference frequency. The 5G-mode LF-band switching subunit is connected to the antenna via a low-pass filter, and the 5G-mode HF-band switching subunit is connected to the antenna via a high-pass filter. The RF switching system for 5G communications has improved isolation performance in both the HF and LF bands and improved insertion loss performance in the HF band.

Abstract: An RF receiver circuit configuration and design limited by conditions and frequencies to simultaneously provide steady state low-noise signal amplification, frequency down-conversion and image signal rejection. The invention provides combined circuits of an RF transceiver architecture that measure antenna reflected power relative to forward power using the error amplifier signal to adjust the gain of the variable gain amplifier in order to compensate for the mismatch between forward reflected power and forward power at the antenna in order to achieve constant radiated power. The RF receiver circuit may be implemented as one of a CMOS single chip device or as part of an integrated system of CMOS components.

Abstract: The control device includes a touch sensor circuit, a control circuit, a driving circuit and a switching circuit. The touch sensor circuit is configured to generate a touch signal and a function signal in response to a touch state of a touch component. The control circuit is activated by a first voltage. The control circuit selectivity generates a self-holding signal according to the function signal when it is activated. The driving circuit is configured to generate a drive signal according to the touch signal or the self-holding signal. The switch circuit is turned on by the drive signal so as to provide the first voltage to the control circuit by the turned-on switching circuit. When the control circuit generated the self-holding signal, the control circuit is configured to continuously transmit the self-holding signal to the driving circuit according to the function signal during a first enabling period.

Abstract: Radio network node and method therein, for communication in a wireless communication system. The radio network node comprises: a plurality of antenna elements, a plurality of transceivers, wherein the plurality of transceivers comprise a first subset of the plurality of transceivers coupled to a first subset of the plurality of antenna elements and a second subset of the plurality of transceivers coupled to a second subset of the plurality of antenna elements; and a controller configured to adjust the first subset of the transceivers to work at a first frequency band, and to adjust the second subset of the transceivers to work at a second frequency band.

Abstract: An apparatus for generating a substantially constant DC reference voltage. The apparatus includes a reference voltage generator configured to generate a substantially constant direct current (DC) reference voltage based on a voltage on a data signal transmission line, wherein the voltage is based on a bandgap reference voltage. In one implementation, the data signal transmission line is a differential signal transmission line and the voltage is a common mode voltage. In another implementation, the data signal transmission line is an I-data signal transmission line and a Q-data signal transmission line, and the voltage is an average or weighted-average of the common mode voltages of the I- and Q-differential signals. In another implementation, the reference voltage is based on a single-ended (e.g., positive- and/or negative)-component or vice-versa of I- and Q-data signals, respectively.

Abstract: A method for attenuating interference generated by intermodulation products with respect to a multiplexed radio signal having a desired frequency the method includes implementing an automatic gain control having a gain setpoint configurable between a first setpoint and a second setpoint lower than the first setpoint; configuring the automatic gain control so that the gain setpoint is equal to the first setpoint; detecting the presence of co-channel interference at the desired frequency; if co-channel interference is detected at the desired frequency, then, if the automatic gain control is active, configuring it so that the gain setpoint is equal to the second setpoint and, if the automatic gain control is not active, configuring it so that the gain setpoint is equal to the first setpoint.

Abstract: A MIMO wireless transceiver includes: antennas, components forming transmit and receive chains coupled to the antennas, a signal combiner, and a predistortion calibration circuit. The transmit chain components include: pre-distorter circuits and power amplifiers (PA)s, The pre-distorter circuits each couple to a transmit chain for pre-distorting an associated signal thereon. The PAs are input coupled to a corresponding transmit chain and output coupled to a corresponding antenna. The signal combiner combines the amplified signals from all of the PAs into a combined output signal.

Abstract: A digital-to-analog converter (DAC) linearization system can include a DAC configured to generate an analog output signal based on a digital input signal, a detector configured to detect noise on a supply voltage and generate a noise detection signal based on the detected noise, and a compensator that is configured to generate a compensated analog signal based on the analog output signal and the noise detection signal.

Abstract: A method for use in an electronic device having an amplification unit, the method comprising: detecting a current temperature of the electronic device when the amplification unit is in a first state in which the amplification unit is operated in accordance with first control value; detecting whether the current temperature meets a threshold; identifying a second control value that is lower than the first control value, when the current temperature meets the threshold; and changing an amount of power supplied to the amplification unit by transitioning the amplification unit into a second state in which the amplification unit is operated in accordance with the second control value.

Abstract: An imaging system that utilizes deterministic bit sequences modulated onto an in-phase component of a carrier frequency and continuously transmitted via a transducer and received for imaging a medium and/or environment is provided. The received signal is demodulated by an in-phase demodulator and a quadrature demodulator and the demodulated components are processed to provide a spatial mapping of a medium or environment being imaged.

Abstract: A radio frequency front end circuit includes an output signal transmission line, an amplifier circuit with an input connected to a radio frequency signal source and an output connected to the output signal transmission line. A harmonic suppression circuit is connected to the amplifier circuit, and includes an active circuit element having a frequency-dependent impedance and is tuned as a reflective trap with a negative capacitance for one or more rejection frequency ranges each corresponding to a multiple of a fundamental frequency of a signal generated by the radio frequency signal source.

Abstract: A system and method of reducing the flicker noise of frequency synthesizers is disclosed. The current source for the synthesizer charge pump current source is modulated so that its flicker noise is displaced to a higher offset frequency. This allows the flicker noise to be filter or nulled out by, for example, a notch filter. The flicker noise can also be modulated into a spread spectrum utilizing sigma delta modulation.

Abstract: Certain aspects involve selectively combining uplink transmissions in a distributed antenna system (“DAS”). For example, a unit of the DAS can receive baseband uplink transmissions from remote units of the DAS via a first channel and a second channel. The unit can generate a first combined uplink signal by combining baseband uplink transmissions received from a first subset of the remote units via the first channel that include data for transmission to a base station. The unit can generate a second combined uplink signal that includes baseband uplink transmissions received from a second subset of the remote units via the second channel and excludes or attenuates baseband uplink transmissions that are received from the first subset of the remote units via the second channel and that lack data for transmission to the base station are excluded or attenuated. The unit can transmit the combined uplink signals to the base station.

Abstract: A contactless communication device includes a receiver unit having differential input terminals for connecting to an antenna. The receiver unit is coupled to a transmitting device and receives an RF signal transmitted by the transmitting device. A first comparator is adapted to generate a first comparator output signal indicative of a relationship between a voltage at a positive input terminal of the receiver unit and a first reference voltage. A second comparator is adapted to generate a second comparator output signal indicative of a relationship between a voltage at a negative input terminal of the receiver unit and a second reference voltage. A first voltage regulation circuit is adapted to regulate the voltage at the positive input terminal in response to the first comparator output signal. A second voltage regulation circuit is adapted to regulate the voltage at the negative input terminal in response to the second comparator output signal.

Abstract: Disclosed herein are wireless transceivers with switches to reduce harmonic leakage. In some embodiments, a transmitter system includes a power amplification system including a first power amplifier configured to amplify a signal at a first cellular frequency band and a second power amplifier configured to amplify a signal at a second cellular frequency band. The transmitter includes a switch coupled between an output of the second power amplifier and a ground potential. The transmitter includes a controller configured to, based on a band select signal, control the switch and selectively enable or disable each of the first power amplifier and the second power amplifier. Selective control of the switch can reduce harmonic leakage compared to a system that does not include the disclosed switches and controls.

Abstract: A method for determining a center frequency in an unlicensed frequency band to use for downlink communication in a cellular network. The method is performed in a network node and comprises the steps of: performing a coarse pre-scan when the network node is in a transmit time slot, yielding respective coarse measurement of signal levels for a plurality of frequencies in the unlicensed frequency band; performing an accurate measurement when the network node is in a receive time slot, yielding respective accurate measurement of signal levels for a plurality of frequencies in the unlicensed frequency band; and determining at least one frequency to use as a center frequency for a downlink communication channel in the unlicensed frequency band.

Abstract: In an embodiment, an apparatus includes a first radio frequency (RF) signal path and a second RF signal path. The first RF signal path can provide a first RF signal when active and the second RF signal path can provide a second RF signal when active. The second RF signal path can include a matching network with a load impedance configured to prevent a resonance in the second RF signal path due to coupling with the first RF signal path when the first RF signal path is active.