Telefonaktiebolaget Lm Ericsson (publ)

Ulf Gustavsson

Lars Sundström

Mikael Coldrey

Robert Baldemair

Stefan Parkvall

Bengt Lindoff

Gunnar Mildh

Icaro L J Da Silva

Johan Rune

Fredrik Gunnarsson

Jinhua Liu

Yi-Pin Eric Wang

Erik Bengt Dahlman

Andres Reial

Jari Tapio Vikberg

Erik A Eriksson

Pål Frenger

Henrik Sahlin

Stefan Wager

Dennis Hui

Martin Hessler

Magnus Stattin

Sven Oscar Petersson

Joakim Axmon

Karl Norrman

Qianxi Lu

Qingyu Miao

Johan Torsner

Pradeepa Ramachandra

Gabor Fodor

Fredrik Athley

Janne Peisa

Kumar Balachandran

Joachim Sachs

Ali S Khayrallah

Gen Li

Claes Tidestav

Thorsten Lohmar

Zhang Zhang

Bo Hagerman

Osman Nuri Can Yilmaz

Lars Lindbom

Niclas Wiberg

Johan Furuskog

Jonas Fröberg Olsson

Niklas Johansson

Torgny Palenius

Jianfeng Wang

Hai Feng Wang

Zhan Zhang

Peter Alriksson

Jose Luis Pradas

Andreas Bergström

Pontus Wallentin

Patrik Rugeland

Henrik Asplund

Martin Johansson

Karl Werner

Patrik Torgny Karlsson

Johan Axnäs

Jonas Kronander

Mårten Ericson

Shehzad Ali Ashraf

Fredrik Lindqvist

Reza Moosavi

Ning He

Dennis Sundman

Mikael Prytz

Håkan Axelsson

Yngve Selén

Andreas Cedergren

Nadia Brahmi

Niklas Jaldén

Ali El Essaili

Jonas Medbo

Elena Myhre

Jörg Huschke

Hugo Tullberg

Emma Wittenmark

Virgile Garcia

Lars Manholm

Peter Von Wrycza

Ke Wang Helmersson

Bengt-Erik Olsson

Thomas Walldeen

Cong Shi

Eleftherios Karipidis

Rui Fan

Walter Müller

Anders Furuskär

Håkan Björkegren

Edgar Ramos

Erik G Larsson

Johan Nilsson

Bo Lincoln

Anders Wallén

Richard Hellberg

Thomas Chapman

Ted Johansson

Leonard Rexberg

A method for reducing peak-to-average power ratio, PAPR, in a Multiple Input Multiple Output, MIMO, communication system is disclosed. The method is performed in a precoder unit and includes: confining, by a differentiable cost function, power of a MIMO signal to be between a lower threshold, P, and an upper threshold, P, and applying a gradient method on the differentiable cost function until reaching a set power target for the MIMO signal, while keeping an Error Vector Magnitude, EVM, below a set EVM level.

Reducing peak-to-average power ratio in MIMO communication system

Methods and apparatus in a fifth-generation wireless communications network, including an example method, in a wireless device, that includes determining a reporting quality threshold for a parameter related to channel state information (CSI); performing a measurement for each of a plurality of beams from a first predetermined set of beams for evaluation; evaluating the measurement for each of the plurality of beams against the reporting quality threshold; discontinuing the performing and evaluating of measurements in response to determining that the reporting quality threshold is met for one of the beams, such that one or more beams in the first predetermined set of beams are not measured and evaluated; and reporting, to the wireless communications network, CSI for the one of the beams.

Network architecture, methods, and devices for a wireless communications network

A link adaptation method is disclosed for a transmitter node configured for spatial multiplexing of signals into streams and for transmission of spatially multiplexed streams over a forward channel, wherein each stream is intended for a receiver node. The method comprises selecting a transmission pre-coding setting for at least one of the spatially multiplexed streams based on an acquired channel estimate of the forward channel, estimating a forward channel disturbance component, wherein the forward channel disturbance component includes signal distortion for the forward channel caused by at least one hardware component of the transmitter node and/or the receiver node, and performing link adaptation for at least one of the spatially multiplexed streams based on the selected transmission pre-coding setting and the estimated forward channel disturbance component. Corresponding apparatus, transmitter node and computer program product are also disclosed.

Link adaptation for spatial multiplexing

A pre-coding method is disclosed of a multi-user, multi-antenna transmitter configured for transmission of respective signals to a plurality of users. The method comprises determining (for each pair of users of the plurality) a spatial correlation value for the pair of users, sorting the plurality of users into a first group and a second group based on the spatial correlation values, generating the respective signals for transmission to the users of the first group by application of linear pre-coding, and generating the respective signals for transmission to the users of the second group by application of non-linear precoding. For example, a particular user may be sorted into the first group when all pairs comprising the particular user have a spatial correlation value that falls below a first correlation threshold value, and the particular user may be sorted into the second group when at least one pair comprising the particular user has a spatial correlation value that falls on or above the first correlation threshold value. Corresponding apparatus, transmitter, base station and computer program product are also disclosed.

Multi-user pre-coding

A pre-coding method is disclosed of a multi-user, multi-antenna transmitter configured for transmission of respective signals to a plurality of users. The method comprises determining (for each pair of users of the plurality) a spatial correlation value for the pair of users, and determining a first correlation threshold value based on the number of users of the plurality. The method also comprises determining whether or not one or more pairs of users has a spatial correlation value that falls on or above the first correlation threshold value. When one or more pairs of users has a spatial correlation value that falls on or above the first correlation threshold value, the method comprises discarding one user comprised in at least one of the one or more pairs to provide a reduced plurality of users, and updating the first correlation threshold value based on the number of users of the reduced plurality. The discarding and updating steps are repeated until none of the spatial correlation values falls on or above the updated first correlation threshold value. Then, the method comprises generating the respective signals for transmission to the users of the reduced plurality by application of pre-coding. Corresponding apparatus, transmitter, base station and computer program product are also disclosed.

Multi-user precoding

Methods and apparatus in a fifth-generation wireless communications, including an example method, in a wireless device, that includes receiving a downlink signal comprising an uplink access configuration index, using the uplink access configuration index to identify an uplink access configuration from among a predetermined plurality of uplink access configurations, and transmitting to the wireless communications network according to the identified uplink access configuration. The example method further includes, in the same wireless device, receiving, in a first subframe, a first Orthogonal Frequency-Division Multiplexing (OFDM) transmission formatted according to a first numerology and receiving, in a second subframe, a second OFDM transmission formatted according to a second numerology, the second numerology differing from the first numerology. Variants of this method, corresponding apparatuses, and corresponding network-side methods and apparatuses are also disclosed.

There is provided mechanisms for beamformed transmission using a precoder. A method is performed by a radio transceiver device. The radio transceiver device comprises hardware. The hardware impacts transmission of signals from the radio transceiver device. The method comprises acquiring channel conditions of a radio propagation channel between the radio transceiver device and at least one other radio transceiver device. The method comprises determining a precoder, in form of a linear precoding matrix, for beamformed transmission towards the at least one other radio transceiver device. The precoder is determined according to the channel conditions and a model of how the hardware impacts the transmission of signals from the radio transceiver device. The method comprises transmitting, using the precoder, a signal towards the at least one other radio transceiver device.

Beamformed transmission using a precoder

A method of a wireless communication transmitter is disclosed for peak-to-average power ratio (PAPR) control of communication symbols with N time-domain signal samples for transmission via each of M antenna elements. The method comprises: applying a PAPR cost function f(x) which has a proximal operator with closed form and is differentiable in an interval, and the proximal operator comprises a parameter lambda for tuning; selecting a value for lambda to perform a trade-off between PAPR and at least one other characteristic of the wireless communication transmitter; selecting a precoding for the collection of samples as a solution to an optimization problem for the selected value for lambda, wherein the optimization problem comprises minimization of an overall cost function comprising at least the PAPR cost function, and wherein solving the optimization problem comprises using the proximal operator of the PAPR cost function. Corresponding apparatus, wireless communication transmitter, radio base station, and computer program product are also disclosed.

Peak-to-average power ratio control

A transmission power allocation method for a transmitter is disclosed. The transmitter includes a number of at least two transmitter paths for spatial multiplexing of two or more signals to be transmitted using respective allocated transmission powers to respective ones of two or more users, wherein each transmitter path includes at least one component causing non-linear distortion and a transmit antenna. The method includes determining a respective received distortion power for each of the two or more users as a function of respective hypothesized transmission powers for the two or more users and based on a model of a spatial behavior of the non-linear distortion. The method also includes allocating respective transmission powers for the two or more users based on the determined respective received distortion powers. Corresponding transmission power allocation apparatus, transmitter, network node, wireless communication device are also disclosed.

Transmission power allocation

Pre-coding methods are disclosed for a transmitter node and for a receiver node, respectively. The transmitter node and/or the receiver node comprises at least one hardware component causing signal distortion for a forward channel and/or a reverse channel Transmitter node reference signals are transmitted by the transmitter node and received by the receiver node, wherein the transmitter node reference signals result from use of a transmitter node transmission pre-coding setting and an allocated transmission power. The receiver node estimates a forward channel disturbance component (including the signal distortion for the forward channel), selects a receiver node reception pre-coding setting based on the estimated forward channel disturbance component, and updates a receiver node transmission pre-coding setting by using the selected receiver node reception pre-coding setting as receiver node transmission pre-coding setting. Receiver node reference signals are transmitted by the receiver node and received by the transmitter node, wherein the receiver node reference signals result from use of the updated receiver node transmission pre-coding setting. The transmitter node estimates a reverse channel disturbance component (including the signal distortion for the reverse channel), selects a transmitter node reception pre-coding setting based on the estimated reverse channel disturbance component, and updates the transmitter node transmission pre-coding setting by using the selected transmitter node reception pre-coding setting as transmitter node transmission pre-coding setting. Corresponding pre-coding apparatuses, transmitter/receiver nodes, and computer program product are also disclosed.

Pre-coding setting

The present disclosure relates to a system () for wireless reference signal distribution. The system () comprises an antenna array () comprising a plurality of transceivers (). The antenna array () is arranged to transmit and receive a in radio signal via the plurality of transceivers (). The system () further comprises a synchronization signal generator () arranged to transmit wirelessly at least one synchronization signal. Each synchronization signal comprises at least one time-dependent signal component, wherein the at least one synchronization signal has at least one time-dependent signal component with an amplitude above a predetermined threshold during a total duration of the at least one synchronization signal. Each transceiver () is connected to a respective synchronization signal receiver () arranged to receive the at least one synchronization signal. The synchronization signal receiver () is arranged to generate a reference signal for the respective transceiver () based on the received at least one synchronization signal. The present disclosure also relates to corresponding methods and computer programs.

Wireless reference signal distribution

A linearization device () is disclosed, which is configured to determine pre-distortion parameters associated with a plurality of non-linear amplifiers (), each associated with a non-linear amplifier characteristic. The linearization device comprises determination circuitry (), a first port () and a second port (). The first port is configured to receive a plurality of channel coefficients indicative of channel characteristics of a plurality of communication paths () between the plurality of non-linear amplifiers and a transmit observation receiver (). The second port is configured to receive, from the transmit observation receiver, a sum of transmission signals generated by the plurality of non-linear amplifiers and transferred over the plurality of communication paths. The determination circuitry is configured to determine the pre-distortion parameters based on the received plurality of channel coefficients, the received sum of transmission signals, and a model of the non-linear amplifier characteristics of the non-linear amplifiers. Corresponding arrangement, wireless transmitter node, cloud based server node, method and computer program product are also disclosed.

Linearization of non-linear amplifiers

The present disclosure relates to a method () for determining scheduling assignments for reducing nonlinear signal distortion, performed in a network node of a wireless communications network. The network node comprises an antenna array arranged to perform beamforming. The method () comprises obtaining (S) channel state information, CSI, relating to respective channels between the network node and at least two wireless devices served by the network node. The method further comprises determining (S) precoding vectors to the at least two wireless devices based on the obtained CSI. The method also comprises determining (S) at least two frequency scheduling assignments for each of the at least two wireless devices. The method additionally comprises estimating (S), for each of the determined at least two frequency scheduling assignments, a respective transmitted nonlinear signal distortion to each of the at least two wireless devices based on the obtained CSI. The method yet further comprises selecting (S) a frequency scheduling assignment of the determined at least two frequency scheduling assignments based on the estimated transmitted nonlinear signal distortions. The present disclosure also relates to corresponding network nodes and computer programs.

Power amplifier-aware user scheduling

Growing community of inventors

Göteborg, Sweden

Ulf Gustavsson