Telefonaktiebolaget Lm Ericsson (publ)

Rockstar Consortium US LP

Rpx Clearinghouse LLC

Mark William Wyville

Pierre-Andre Laporte

Spendim Dalipi

Bilel Fehri

Lars Johan Thorebäck

Alex Stephenne

Bo Göransson

Fredrik Huss

Mark Edward Rollins

Edward Sich

Russell Clifford Smiley

Peter Malcom Coe

Vijay Venkateswaran

Johan Thorebäck

A method in a network node and an apparatus for determining passive intermodulation (PIM) characteristics at the network node are provided. According to one aspect, a method includes capturing signals from each of at least one antenna port at a first time and a second time. The method includes determining a first covariance matrix based on signals captured at the first time. The method also includes determining a second covariance matrix based on signals captured at the second time. The method further includes determining a difference matrix, the difference matrix being based on a difference between the first and second covariance matrices, the difference matrix corresponding to changes in PIM between the first time and the second time.

Distortion detection with multiple antennas

There is provided mechanisms for mitigating interference in a network node. A method is performed by a control device (). The method comprises receiving (S) radio signals comprising at least one desired signal and interference, estimating (S) a characteristic of the interference, wherein the estimation comprises calculating correlation statistics of power levels of frequency sub-bands comprising the interference with frequency sub-bands comprising the received radio signals. The method comprises determining (S) an interference suppression matrix to suppress the interference in the frequency sub-bands of the received radio signals based on the estimated characteristic of the interference, wherein the interference suppression matrix is further determined based on information from inter-band interference observed across distinct sub-bands of the received radio signals. The method comprises applying (S) the interference suppression matrix on the received radio signals to mitigate the interference from the received radio signals.

Method and control device for mitigating interference

Embodiments include methods for determining intermodulation distortion (IMD) present in an uplink channel received by a network node in a wireless communication network. Such embodiments include, for each of a plurality of time period pairs comprising first and second time periods: measuring a first parameter for an uplink channel received and a second parameter for each of a plurality of downlink channels transmitted by the network node; and for the uplink channel, determining a first difference between the first parameter measured during the first time period and the first parameter measured during the second time period. Such embodiments also include, based on the first difference and the second parameters, determining a predictive model for an IMD signal, associated with the downlink channels, that can be received by the network node in the uplink channel. For example, the predictive model can be used to adjust transmitter settings to improve IMD performance.

Methods for modeling intermodulation distortion (IMD) present in received signals

A method and network node for detection of passive intermodulation (PIM) are disclosed. According to one aspect, a method includes determining values of a covariance matrix based at least in part on uplink signals received by the network node radio. The method also includes determining a plurality of uplink (UL) channel 5 eigenvalues based at least in part on an eigen-component acquisition technique. The method further includes determining a presence or absence of PIM based at least in part on a plurality of the UL channel eigenvalues.

Eigenvalue-based passive intermodulation detection

A first radio node for uplink and downlink co-scheduling is provided. The first radio node includes processing circuitry containing instructions executable to configure the first radio node to: determine a scheduling restriction for joint uplink and downlink scheduling based on passive intermodulation (PIM) generated during simultaneous uplink and downlink communications where the uplink communications corresponds to communications from a second radio node to the first radio node, and perform communications according to the scheduling restriction.

Uplink-downlink co-scheduling with beam control and passive intermodulation awareness

A first radio node including processing circuitry configured to configure the first radio node to: obtain a first interference subspace, obtain beamforming weights based on the first interference subspace where the beamforming weights configured to modify a radiation pattern in at least one communication direction of at least one interference source, and perform wireless communications based on the beamforming weights.

Radiation pattern modification in the presence of interference sources in frequency division duplex (FDD) systems

Systems and methods are disclosed herein that related to Peak-to-Average Power Ratio (PAPR) reduction in a (e.g., massive) Multiple-Input Multiple-Output (MIMO) Orthogonal Division Multiplexing (OFDM) transmitter system. In some embodiments, a method of operation of a MIMO OFDM transmitter system comprises, for each carrier of two or more carriers, performing precoding of a plurality of frequency-domain input signals for the carrier to provide a plurality of frequency-domain precoded signals for the carrier, the plurality of frequency-domain input signals for the carrier being for a plurality of transmit layers for the carrier, respectively. The method further comprises processing the frequency-domain precoded signals for the two or more carriers in accordance with a multi-carrier Convex Reduction of Amplitudes (CRAM) processing scheme to provide a plurality of multi-carrier time-domain transmit signals for a plurality of antenna branches, respectively, of the MIMO OFDM transmitter system.

Convex reduction of amplitudes for OFDM MIMO with multiple carriers

A method and system for detecting PIM signals in a wireless communication base station are disclosed. According to one aspect, a method includes receiving radio frequency, RF, signals over a frequency band spanning a plurality of frequencies of signals transmitted by at least a first transmitter external to the base station and at least a second transmitter. The method includes determining frequencies at which signals are present among the received radio frequency signals. PIM signal frequencies are calculated based on the determined frequencies at which signals are present. The method includes determining whether the calculated PIM signal frequencies interfere with selected uplink channels.

Cell site passive intermodulation detection receiver

A method, detector and radio unit for non-linear interference detection in a communication system having a victim signal and an offending signal are disclosed. According to one aspect, a method includes determining a magnitude of the victim signal raised to a first power to produce a first signal. The method also includes determining a magnitude of the offending signal raised to a second power to produce a second signal. The first signal and the second signal are correlated to produce an output signal indicative of an extent to which the offending signal interferes with the victim signal.

Non-linear interference detection

Systems and methods providing improved duplexer isolation are disclosed. In one embodiment, a system having improved duplexer isolation includes a duplexer system and one or more digital filters. The duplexer system includes a first transmit port, a second transmit port, a receive port, and an antenna port. The duplexer system is configured to receive a first transmit signal at the first transmit port and a second transmit signal at the second transmit port, where the first and second transmit signals are balanced transmit signals. The duplexer system is configured to combine the first and second transmit signals at the antenna port. The one or more digital filters are configured to cause destructive combining of transmit leakage signals at the receive port. As a result, the isolation of the duplexer system is substantially improved.

Duplexer system and associated digital correction for improved isolation

A method and system for identifying passive intermodulation, PIM, at a base station in a wireless communication system are disclosed. In some embodiments, a method includes measuring the noise floor in a radio frequency, RF, channel of an uplink carrier, the uplink carrier comprising a carrier transmitted from a wireless device to the base station. The method includes comparing the measured noise floor to a predetermined noise floor. The method also includes determining whether PIM is present based on a result of the comparison.

Uplink spectrum analysis technique for passive intermodulation (PIM) detection

Embodiments of a dual-mode radio system are disclosed. In one embodiment, the radio system includes a first radio unit including a transmitter, a receiver, an antenna, and switching circuitry adapted to couple either an output of the transmitter of the first radio unit or an input of the receiver of the first radio unit to the antenna of the first radio unit. In addition, the radio system includes a second radio unit including an antenna and either a transmitter having an output coupled to the antenna of the second radio unit, a receiver having an input coupled to the antenna of the second radio unit, or both a transmitter having an output selectively coupled to the antenna of the second radio unit and a receiver having an input selectively coupled to the antenna of the second radio unit. The radio system has both a full-duplex mode and a half-duplex mode.

Dual-mode radio system having a full-duplex mode and a half-duplex mode

Systems and methods for suppressing transmitter noise in a receive band of a co-located receiver that are suitable for wideband applications are disclosed. In one embodiment, a transmitter is configured to upconvert and amplify a digital transmit signal to provide an analog radio frequency transmit signal at an output of the transmitter that includes a desired signal in a transmit band of the transmitter and transmitter noise in a receive band of a main receiver. The main receiver is configured to amplify, downconvert, and digitize an analog radio frequency receive signal to provide a digital receive signal. The digital feedforward transmit noise cancellation subsystem is configured to process the digital transmit signal to generate a digital transmitter noise cancellation signal that is representative of the transmitter noise in the receive band and is subtracted from the digital receive signal to thereby provide a compensated digital receive signal.

Digital suppression of transmitter intermodulation in receiver

Systems and methods are disclosed for active cancellation of transmitter leakage in a radio receiver that reduce power consumption and/or reduce noise in a desired receive frequency band. In some embodiments, in order to cancel transmitter leakage in a receive path, a cancellation signal is injected into the receive path in an upstream direction. By injecting the cancellation signal in the upstream direction, a noise component of the cancellation signal propagates through the receive path in the upstream direction and is either passed through a receive antenna or attenuated by an upstream component. Conversely, a desired component of the cancellation signal is reflected by an upstream filter and, thereafter, propagates through the receive path in the downstream direction to thereby cancel the transmitter leakage in the receive path. In this manner, active transmitter leakage cancellation can be performed while minimizing degradation of receiver sensitivity.

Active cancellation of transmitter leakage in a radio receiver

A method, apparatus and receiver for detecting intermodulation distortion (IMD) affecting a received signal in a wireless receiver are provided. One method includes determining a measurement indicative of IMD based on at least one transmit signal. When the measurement indicative of IMD exceeds a first pre-determined level, at least one sample of an amplitude of a signal output by the wireless receiver is collected in a first data set. When the measurement indicative of intermodulation distortion does not exceed a second pre-determined level, the second predetermined level being less than the first predetermined level, at least one sample of an amplitude of the signal output by the wireless receiver is collected in a second data set. A comparison is performed based on data of the first data set and on data of the second data set to determine a measure of IMD.

Growing community of inventors

Ottawa, Canada

Mark William Wyville