Telefonaktiebolaget Lm Ericsson (publ)

Cambridge Silicon Radio Limited

Arm Limited

Anders Berkeman

Leif Wilhelmsson

Jim Svensson

Shousheng He

Dominic Hugo Symes

Pex Tufvesson

Carl Drougge

A method for controlling projection of an image in an extended reality device is disclosed. The extended reality device comprising an optical element, a display, and a motion tracker, wherein the optical element and/or the display are mounted movement flexible in the extended reality device. The method comprises obtaining motion information of the extended reality device from the motion tracker; determining a compensating movement of the optical element and/or the display for projection of the image based on the obtained motion information of the extended reality device; and controlling projection of the image by moving the optical element and/or the display based on the determined compensating movement. Corresponding computer program product, apparatus, and extended reality headset are also disclosed.

Projection of an image in an extended reality device

Arithmetic coding utilizes probability values associated with contexts and context indexed values. The probability values are stored within a random access memoryfrom where they are fetched to a cache memorybefore being supplied to an arithmetic encoder and decoder. The context indexed values used are mapped to the plurality of contexts employed such that context indexed values used to process data values close by in a position within the stream of data values being processed have a greater statistical likelihood of sharing a group of contexts than context values used to process data values far away in position within the stream of data values. Thus, a group of contexts for which the probability values are fetched together into the cache memorywill have an increased statistical likelihood of being used together in close proximity in processing the stream of data values. This reduces the number of cache flush operations and cache line fill operations.

Storage of probability values for contexts used in arithmetic coding

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

Method and device for generating an address value for addressing an interleaver memory. Consecutive address fragments to which a most significant bit(s) is to be appended are generated. Only a fraction of the address fragments generated, which potentially will exceed a maximum allowable value, is compared to the maximum allowable value. If the compared address fragment exceeds the maximum allowable value it is discarded. If the compared address fragment does not exceed the maximum allowable value it is accepted.

Address generator for an interleaver memory and a deinterleaver memory

A Decimation In Frequency (DIF) Fast Fourier Transform (FFT) stage is used in an N bin FFT, wherein N is an even integer. The DIF FFT stage includes swap logic that receives a first input sample, x(v), and a second input sample, x(v+N/2), and selectively supplies either the first and second input samples at respective first and second swap logic output ports or alternatively the second and first input samples at the respective first and second swap logic output ports, wherein 0&#x2266;v&#x3c;N/2. The DIF FFT stage further includes a summing unit for adding values supplied by the first and second swap logic output ports; a differencing unit for subtracting values supplied by the first and second swap logic output ports; and twiddle factor logic that multiplies a value supplied by the differencing unit by a twiddle factor, W, where s is an integer representing an amount of circular shift of N input samples.

Circular fast fourier transform

A coarse estimate of a location of an information carrying part of a symbol in a received signal in a telecommunication system is generated. This involves generating correlation values by correlating the received signal with a delayed received signal. A maximum correlation value of the correlation values is identified, and a duration in time during which the correlation values are greater than or equal to a predetermined percentage of the maximum correlation value is identified, wherein the duration in time begins at a first moment in time and ends at a second moment in time. The coarse estimate of the location of the peak correlation value is set equal to a moment in time between the first moment in time and the second moment in time, for example, a midpoint between the first moment in time and the second moment in time.

Initial parameter estimation in OFDM systems

A first number is multiplied by a second number, by representing the first number as a first set of one or more W-bit wide numbers, and representing the second number as a second set of one or more W-bit wide numbers. Each of the W-bit wide numbers from the first set is paired with each of the W-bit wide numbers from the second set. For each pair of W-bit wide numbers, a set of sub-partial products is generated. Combinations of the sub-partial products are formed such that each combination is representable by a W-bit wide lower partial product and a carry out term that has fewer than W bits. The W-bit wide lower partial products and the carry out terms are combined to form the product of the first number and the second number. The carry out term is advantageously representable by (W/2)+1 bits.

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Lund, Sweden

Anders Berkeman