Telefonaktiebolaget Lm Ericsson (publ)

Bernt Johansson

Leonard Rexberg

Bo Berglund

Jan-Erik Thillberg

Jacob Österling

Farshid Ghasemzadeh

Thorsten Nygren

An transmitter arrangement and a method therein are provided for linearization of an active antenna array. The active antenna array comprises a plurality of antenna elements, which are associated with a plurality of power amplifiers. The active antenna array is further associated with a precoder having a number of input and output ports. The method comprises obtaining a first signal provided to the antenna array via a first input port of the precoder. The method further comprises adapting a pre-distorting linearizer connected to the first input port based on the first signal and on feedback from the plurality of antenna elements, resulting from the propagation of the first signal via the precoder, and via the plurality of power amplifiers. Embodiments are also provided for adapting a pre-distorting linearizer based on a plurality of input signals and feedback from the plurality of antenna elements.

Linearization of active antenna array

There is provided automatic gain control of radio chains of a receiver. At least two radio frequency (RF) signals are received. Each RF signal is received on an individual radio chain from an antenna array. By comparing the at least two RF signals to a threshold it is determined whether to perform gain control or not of at least one of the at least two RF signals before analog combining of the at least two RF signals. A notification is sent to a detector regarding whether gain control is performed or not. Analog combining of the at least two RF signals is performed, thereby generating a single input to the detector.

Gain control in radio chains of a receiver

Embodiments of the present invention provide an apparatus () for feeding an antenna array () comprising at least first and second antenna elements (). The apparatus comprises a first transmitting element () configured to receive a first base band signal (-) and to feed a first feed signal () to a first antenna element (), the first transmitting element () comprising a first power amplifier (). The apparatus also comprises a second transmitting element () configured to receive a second base band signal () and to feed a second feed signal () to a second antenna element (), the second transmitting element () comprising a second power amplifier (). A tapering control unit () is adapted to provide a tapering function between the first feed signal to the first antenna element and the second feed signal to the second antenna element.

Apparatus and method for use with antenna array

A radio communication receiver apparatus is configured to process multiple radio frequency bands in a telecommunication system. The apparatus includes a plurality of digital receiver chains wherein each digital receiver chain is coupled to receive a digital representation of the multiple radio frequency bands, including a particular radio frequency band for processing by the respective digital receiver chain. Each digital receiver chain includes a digital receiver that is programmable to select a particular radio frequency band from the digital representation of the multiple radio frequency bands, and configured to down convert the selected radio frequency band into a digital baseband signal associated with the particular radio frequency band. Built in calibration is provided by operation of direct radio frequency technology.

Radio communication receiver apparatus and method

Communication systems and methods in a communication system for allocating an amount of baseband resource in one of a plurality of digital units to a radio unit serving a cell are provided. The methods include estimating the amount of the baseband resource to be allocated to the radio unit, identifying a digital unit of the plurality of digital units on which a neighbor radio unit, serving a neighbor cell, situated in a geographical vicinity of the cell is allocating baseband resource, determining that the digital unit has available baseband resource of the estimated amount, and if so, allocating the estimated amount of baseband resource in the digital unit to the radio unit.

Communication systems and methods in a communication system

A radio module is disclosed that includes a baseband device, a layer device, and a multi radio antenna. The baseband device is arranged to perform digital modulation and/or demodulation. The baseband device provides a data connection available to a digital system using the radio module for radio communication. The multi radio antenna includes an analog radio device arranged to perform analog signal processing, and an antenna array connected to the analog radio device. The layer device is arranged to map each baseband device to one or more of the at least one multi radio antennas, and the radio module is connectable to a second equivalent radio module. A corresponding radio assembly and method are also disclosed.

Radio module, radio assembly and corresponding method

A radio communication transmitter apparatusis operable to transmit multiple radio frequency bands in a telecommunication system. The apparatus comprises a plurality of digital transmitter chainsto, wherein each digital transmitter chain is coupled to receive a digital representationtoof a respective base band signal for processing by a respective digital transmitter chain. Each digital transmitter chaintocomprises a digital transmittertothat is adapted to convert a respective digital base band signal directly into a digital representation of a radio frequency signalto. A digital combining unitis coupled to receive the output of each digital transmitter chainto, and adapted to combine the digital representation of a radio frequency signaltoreceived from each digital transmitter chaintointo a digital representation of a radio frequency signalcomprising multiple radio frequency bands. A digital to analogue converteris coupled to receive the digital representation of a radio frequency signalcomprising multiple radio frequency bands, and adapted to convert the digital representation of a radio frequency signalinto an analogue radio frequency signalcomprising multiple radio frequency bands.

Radio communication transmitter apparatus and method

A digital radio module comprises a modular architecture for use in a multi-band multi-standard radio communication apparatus. The digital radio module comprises one or more digital transmitter sub modules, each digital transmitter sub module comprising a plurality of digital transmitter chains, and one or more digital receiver sub modules, each digital receiver sub module comprising a plurality of digital receiver chains. Each of the digital transmitter sub modules and digital receiver sub modules comprises a respective control unit for individually configuring each digital transmitter sub module and digital receiver sub module such that the digital radio module is operable to transmit and/or receive multiple different carrier frequency signals in one or more different modes of operation.

Radio communication apparatus method

An output signal from an inherently non-linear device is linearized by sampling an original signal with a first sampling rate for a desired signal resolution of an achieved digital original signal message; and re-sampling the original signal at a second sampling rate for creating a digital pre-distortion signal to be added to the achieved digital original signal message. The second sampling rate is greater than the first sampling rate, thereby forming a digital pre-distorted signal to be fed to the inherently non-linear device after digital to analog conversion.

Pre-distortion using a by-pass signal

A method is disclosed for obtaining high throughput linearity using a pre-distorter in front of a RF power amplifier, for instance a multi-carrier power amplifier (MCPA) for a communications system. The method can be carried out off-line to thereby save costs and components otherwise needed for a common on-line feed back. In a first step calibration is performed by measuring by an off-line spectrum analysis an output spectrum of the power amplifier and simultaneously applying a known input signal. As a next step digitized parameters characterizing the power amplifier are calculated in the frequency domain by comparing spectrum points between input spectrum and output spectrum. Thereafter calculated and weighted digitized parameters are transferred to a pre-distorting device. In a third step the known signal spectrum is transferred to the pre-distorting device feeding its output signal together with the original known signal spectrum to the power amplifier input thereby compensating for power amplifier non-linearity and minimizing inter-modulation products. Finally in a fourth step an uncompensated known input spectrum is compared with a corresponding compensated output spectrum of the power amplifier and the steps of calibration calculation are repeated until a best optimization input signal to the power amplifier regarding the inter-modulation products of the output signal has been achieved.

Off-line MCPA calibration

A method and an arrangement is disclosed for linearizing the output signal from an inherently non-linear device, e.g. an amplifier, producing intermodulation or non-linear products. A pre-distorter having a unity transfer function is located between a signal input and the input of the inherently non-linear device. Furthermore a second device forming a post-distorter is coupled to the output of the nonlinear device in a way to be able to handle the amplified output signal or a portion of the output signal. According to the present method the post-distorter is optimized to give as output the same signal spectrum content as what is input to the non-linear device, whereafter the achieved parameters of the post-distorter are transferred to the pre-distorter. In other words a copy of the optimized post-distorter is then used as a pre-distorter in front of the non-linear device to obtain an improved output signal in terms of signal quality from the inherently non-linear device. The post-distorter is then optimized once more and parameters are again transferred to the pre-distorter as a further as a further small correction. In operation this is then generally repeated in a suitable scheduled way to give an ongoing correction to the pre-distortion. The pre-distorter and post-distorter may both be either digital devices or analog devices.

Pre-distortion of non-linear devices by post-detection

The invention relates to a method and an arrangement for establishing a connection between two fixed nodes in a mobile radio system. Adaptive antennas are utilized to achieve narrow beams. The connection is established via a reflecting body.

Method and an arrangement in a mobile radio system

A method and a system for an array antenna calibration are disclosed. The method and system provide a sensor system presenting a sensor device at each antenna element, which sensor devices include digital receivers. Each digital receiver produces a complex base-band I/Q-signal. The outputs of the digital receivers are fed to a Digital Signal Processing device for adding them up to obtain a resulting signal which when converted to a DC signal presents a maximum if all individual signals have the same phase. The search for a maximum of this DC voltage is then used by the Digital Signal Processor for creating source signal phase control signals. By adjusting source signal phases for obtaining maximum added DC voltage derived from the sensor system the phases at the antenna elements will be calibrated. In this manner an adaptive array antenna is simply calibrated even during operation by compensating the base-band I/Q-signals for the intentional phase settings used for achieving a specific channel adaptive array antenna direction.

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Värmdö, Sweden

Bernt Johansson