Telefonaktiebolaget Lm Ericsson (Publ)

Cambridge Silicon Radio Limited

Shousheng He

Anders Berkeman

Ashkan Kalantari

A WIRT system uses synchronizable PPM waveforms to convey information and power from an ET to a remote, far-field EH. In so doing, the solution presented herein reduces receiver complexity, optimizes power transfer, and meets information transfer requirements. The synchronizable PPM waveform comprises a plurality of pulsed-modulation symbols, each of which comprises one or more pulses position-modulated responsive to the information to be conveyed to the EH. The ET configures at least one pulse in each symbol of said synchronizable PPM waveform according to one or more synchronization constraints to enable symbol synchronization at the EH. The EH converts the RF power of the received synchronizable PPM waveform to a DC voltage, and synchronizes the received PPM waveform to extract the information in the PPM waveform.

Synchronizable pulse position modulation waveform with guard-symbols for efficient far-field wireless information and power transfer

There is provided mechanisms for polarization aligned transmission towards a receiver device. A method is performed by a mobile wireless device. The mobile wireless device comprises an antenna array. The method comprises obtaining, based on analysis of an image of the receiver device as captured by an image capturing unit, information of orientation of the receiver device. The orientation pertains to orientation of an antenna of the receiver device towards which a signal is to be transmitted. The method comprises transmitting the signal from the antenna array towards the receiver device using a wave. The wave has its polarization aligned, based on the orientation of the receiver device, with the antenna of the receiver device.

Polarization aligned transmission towards a receiver device

Systems and methods are disclosed herein for Wireless Power Transfer (WPT) using radiative coupling and dynamic beamforming. In some embodiments, a method of operation of an Energy Transmitter (ET) comprises, for each time period (TP) of a plurality of time periods ({TP}), for each time slot (TS) of one or more time slots ({TS}), transmitting, during TSof TPon a frequency f, a radio frequency signal (S(i,j)) that is modulated with a signature of a particular Energy Harvester (EH). The method further comprises, for each TP, attempting, during TP, to receive, from the particular EH on a frequency f, a radio frequency signal (S(i)) that is modulated with the signature of the particular EH. In this manner, continuous WPT is provided. Corresponding embodiments of an ET are also disclosed. Embodiments of a method performed by an EH and corresponding embodiments of an EH are also disclosed.

Wireless power transfer using dynamic beamforming

A receiver () for extracting a desired signal component () from a received signal, which received signal contains the desired signal component () and may contain an interfering signal component (), wherein the receiver () comprises a first mixer () which generates an intermediate frequency signal containing a frequency-shifted version of the received signal and a frequency-shifted version of an image of the received signal, the receiver further comprising: a second mixer () for shifting the desired signal component () of the intermediate frequency signal such that it is centered on a baseband frequency, so as to generate a first composite signal containing the shifted desired signal component () and a shifted version of any interfering signal component () contained in the image of the received signal; a third mixer () for shifting an image of the desired signal such that it is centered on the baseband frequency, so as to generate a second composite signal containing the shifted image () of the desired signal component and a shifted version () of any interfering signal component contained in the received signal; an estimator () for estimating, from the first and second composite signals, a coefficient indicative of the amount of the interfering signal () component that is present with the desired signal component () in a selected one of the composite signals; a multiplier () for scaling the complex conjugate of the selected composite signal by the coefficient so estimated; and an adder () for subtracting the scaled signal output by the multiplier () from the other composite signal to obtain a scaled version of the desired signal component.

Image rejection

A receiver for isolating a wanted signal in a received signal, the receiver comprising a downconverter for downconverting the received signal in frequency to produce a downconverted signal, a filter with a passband intended for isolating that part of the spectrum of the downconverted signal that contains the wanted signal and a controller that seeks to avoid or reduce the effect of passband intrusion in the form of a negative frequency representation of an interferer, appearing in the spectrum of the received signal, upconverted in frequency to the passband. The invention consists in corresponding methods also.

Downconversion strategies for reducing interference in wanted signals

A filter device and method for suppressing effects of Adjacent-Channel Interference of a received signal in a Frequency-Division-Multiple-Access system by filtering a baseband signal of the received signal. The filter device comprises an interference filter, which is a complex digital Single-Input-Multiple-Output, SIMO, filter that is adapted to simultaneously generate a first signal filtered at an upper-frequency-band and a second signal filtered at a lower-frequency-band, wherein the first signal is separate from the second signal. The filter device also comprises a selector adapted to select one of the signals as the output from the filter device.

Filter and method for suppressing effects of adjacent-channel interference

A method of compensating for dc offset of a received signal transmitted over a channel having a plurality of paths, the received signal comprising a modulated data signal and a modulated known training sequence signal, the method comprising the steps of: constructing () from the known training sequence signal a first regression matrix; path-combining () the incrementally rotated elements of the first regression matrix to produce the elements of a trend matrix; deriving () a neutralized second regression matrix from the first regression matrix and the trend matrix; utilising the neutralized second regression matrix to compensate () for dc offset of the received modulated data signal.

Method and apparatus for DC offset compensation in a digital communication system

A digital signal, x(n) (where n is an integer), is decimated by determining a signal vector, y(k), of size M by partitioning samples of the digital signal, x(n) according to sampling phases of the samples. The signal vector, y(k), is projected onto an N-dimensional sub-space, wherein N is an integer and N&#x3c;M. Where the digital signal is generated by means of oversampling, it is possible to perform decimation in a way that optimizes the signal-to-noise ratio (SNR) of the decimated signal by suitably determining the sub-space onto which the signal vector will be projected.

Digital signal decimation by subspace projection

Methods and apparatus taught herein provide for symbol alignment between diversity signals in a communication receiver. For example, in one embodiment, a method of symbol aligning diversity signals in a communication receiver comprises generating diversity sample sets for a received signal and hypothesizing two or more relative symbol alignments for the diversity sample sets. The method further includes jointly determining a preferred relative symbol alignment and a preferred synchronization position for the diversity sample sets by evaluating a function that is dependent on relative symbol alignment and synchronization position according to the hypothesized relative symbol alignments and a number of candidate synchronization positions. In one embodiment, a burst-type communication receiver uses Single-Antenna-Interference-Cancellation (SAIC) processing, and over-samples the received signal to obtain the diversity sample sets as sub-channels of the received signal. A diversity processor in the receiver jointly determines the best relative symbol alignment and synchronization position.

Method and apparatus for symbol alignment in diversity signal reception

A method of estimating a transmission channel () comprises receiving a signal burst, which includes a sequence of training symbols; and determining () a desired synchronization position (p) of the training sequence with respect to the received signal burst. The method further comprises determining estimates of the transmission channel as a function of the synchronization position (p) and a size of the equalizer window (m); and determining the desired synchronization position and the size of the equalizer window by calculating an error measure based on the received signal burst and the determined estimates for selected values of the synchronization position and of the size of the equalizer window, where the values of the size of the equalizer window are selected between predetermined upper (m) and lower (m) bounds.

Synchronization and estimation of a transmission channel

A method of determining a DC offset in a communications signal received via a communications channel, the communications signal comprising a sequence of training symbols. The method comprises providing a channel estimate of the communications channel based on said sequence of training symbols; determining, based on the channel estimate, an estimate of a noise contribution introduced by the communications channel; and determining an estimate of the DC offset from the determined estimate of the noise contribution.

Method and corresponding arrangement for DC offset compensation using channel estimation

Interference rejection in a wireless communication system involves determining a complement spatial-temporal signal subspace that is complement to a spatial-temporal signal subspace of an interference signal included in a received signal. The received signal is projected onto the complement spatial-temporal signal subspace, whereby the interference signal included in the received signal is reduced. Determining the complement spatial-temporal signal subspace can include estimating the interference signal; determining a Block Yule-Walker matrix for the estimated interference signal; and determining the complement spatial-temporal signal subspace from the Block Yule-Walker matrix.

Single antenna interference cancellation via complement subspace projection in spatial-temporal expansion of noise estimation

A method and apparatus for receiving a communication signal r(t) subject to noise n(t) over a communication channel () is disclosed. The method comprises the steps of: receiving () the communication signal r(t) comprising the noise n(t), estimating () the amount of noise n(t) in the communication signal r(t), and determining () the hue of the estimated amount noise n(t), wherein the received communication signal r(t) is passed through a whitening filter if the hue of the noise n(t) is greater than a predetermined threshold level.

Colored interference identification

A method of and apparatus for single antenna interference rejection (SAIR) relaxation. Interference in a received signal is reduced by performing synchronization and whitening of the received signal. The synchronization and whitening includes performing the following steps at least one time: 1) performing a synchronization and vector-noise-correlation estimation of an input signal to yield an interference model; and 2) performing a spatio-temporal whitening operation using the interference model and the input signal to yield an updated received signal. The input signal is the received signal when the step of performing the synchronization and vector-noise-correlation estimation is performed a first time. The input signal is the updated received signal when the step of performing the synchronization and vector-noise-correlation estimation is performed following the first time.

Method of and apparatus for single antenna interference rejection through relaxation

A method of and apparatus for reducing interference in a received signal. A normalized noise correlate is determined using the received signal and a first channel estimate of the received signal. Conditional whitening-filter settings are determined using the normalized noise correlate. A whitening filter is applied to the received signal in accordance with the conditional whitening-filter settings. A synchronization adjustment of an updated received signal is performed. A second channel estimate, which may be of the same span as the first channel estimate, is determined using an updated synchronization position and the updated received signal.

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Södra Sandby, Sweden

Shousheng He