GB2642267A

GB2642267A - Constellations for signal modulation

Info

Publication number: GB2642267A
Application number: GB2409342.9A
Authority: GB
Inventors: Rezaie Sajad; Barbu Oana-Elena; Johannes Korpi Dani
Original assignee: Nokia Technologies Oy
Current assignee: Nokia Technologies Oy
Priority date: 2024-06-28
Filing date: 2024-06-28
Publication date: 2026-01-07
Also published as: GB202409342D0; WO2026002459A1

Abstract

A first apparatus obtains a selection, from a set, of a constellation having a non-zero mean (NZM) and supporting a superimposed pilot (SP), obtains a modulated DC component of the selected NZM constellation, and applies the modulated DC offset to the selected NZM constellation to provide an adapted NZM constellation for signal modulation. A second apparatus obtains an indication of a selected NZM, obtains a modulated DC component, and applies the DC component to provide an adapted NZM constellation for signal demodulation. The first and second apparatuses may be a user device (UE) or network device (gNB). The first apparatus may report to the second apparatus the selected NZM constellation and its capability to modulate the DC component. The selected constellation may be a learned constellation, such as via machine learning (ML). Modifying the NZM constellation allows the peak-to-average power ratio (PAPR) to be reduced from the original NZM constellation. A signalled configuration may comprise a rescaling factor coefficient for scaling down the DC component, for example by scaling the pilot sequence. The DC component may be modulated by rotating the DC component over different REs.

Description

[0001] Constellations for Signal Modulation

[0002] Field

[0003] Example embodiments relate generally to constellations for signal modulation.

[0004] Background

[0005] The Third Generation Partnership Project (3GPP) has and is developing standards for Fourth Generation (4G), also known as Long Term Evolution (LTE), Fifth Generation (5G), also known as New Radio (NR), communications systems and Sixth Generation (6G) communication systems. Such communication systems involve use of digital signal modulation schemes such as, but not limited to, Quadrature Phase-Shift Keying (QPSK) and Quadrature Amplitude Modulation (QAM). Data is modulated and transmitted using data points of a constellation.

[0006] Summary

[0007] The scope of protection sought for various embodiments of the invention is set out by the independent claims. The embodiments and features, if any, described in this specification that do not fall under the scope of the independent claims are to be interpreted as examples useful for understanding various embodiments of the invention.

[0008] A first aspect provides a first apparatus comprising: means for determining a configuration for modulation of a direct current, DC, component of a constellation, wherein the configuration comprises one or more parameters for configuring the modulation of a DC component of the constellation; means for modulating the DC component of the constellation for a signal based on the configuration; and means for transmitting the modulated DC component of the constellation to a second apparatus.

[0009] In some example embodiments, the one or more parameters may comprise at least one of: a coefficient for scaling the DC component; one or more first values for setting the DC component; one or more second values for scaling a pilot sequence of the constellation using the DC component; or one or more third values for shifting and/or rotating the DC component.

[0010] In some example embodiments, the constellation may be a selected learned constellation of the first apparatus supporting a superimposed pilot, SR In some example embodiments, the first apparatus may further comprise means for reporting at least an indication of the selected learned constellation to the second apparatus, wherein the second apparatus is capable of receiving the signal.

[0011] In some example embodiments, the selected learned constellation may have a non-zero mean, NZM.

[0012] In some example embodiments, the first apparatus may further comprise means for reporting at least a capability of the first apparatus to modulate the DC component of the constellation to the second apparatus.

[0013] In some example embodiments, the configuration may be determined, for example obtained, in response to the reporting of the at least the capability.

[0014] In some example embodiments, the first apparatus may further comprise: means for scaling the DC component based on at least one of: the coefficient for scaling the DC component; or the one or more second values for scaling the pilot sequence of the constellation.

[0015] In some example embodiments, the first apparatus may further comprise: means for shifting and/or rotating the DC component based on the one or more third values for shifting and/or rotating the DC component.

[0016] In some example embodiments, the first apparatus may further comprise: means for extracting the DC component from the constellation; means for modulating the extracted DC component based on the configuration; and means for applying the modulated extracted DC component to the constellation to provide an adapted constellation for the modulation of the signal.

[0017] In some example embodiments, a resource element, RE, allocated to the signal may comprise a data component with a first TX power and a pilot component with a second TX power.

[0018] In some example embodiments, the configuration may comprise at least a configuration for learning or relearning of the constellation, wherein said configuration comprises a plurality of modulation pilot sequences for modulating the DC component of the constellation.

[0019] In some example embodiments, the learned constellation may a zero mean, ZM or nonzero mean, NZM.

[0020] In some example embodiments, the first apparatus may further comprise: means for learning or relearning of the constellation with embedded modulated DC component based at least in part on the configuration.

[0021] In some example embodiments, the means for learning or relearning of the constellation may be configured to iteratively learn or relearn the constellation based at least in part on the plurality of modulation pilot sequences.

[0022] In some example embodiments, the configuration may further indicate at least one constraint for the learning or relearning of the constellation, and the learning or relearning of the constellation may further be based on the at least one constraint.

[0023] In some example embodiments, the at least one constraint comprises at least one of: an upper limit of estimated peak-to-average power ratio, PAPR; an upper limit of the DC component; or a ratio between power allocated to data and power allocated to pilot symbols.

[0024] In some example embodiments, the first apparatus may further comprise: means for reporting at least a capability of the first apparatus to learn or relearn the constellation.

[0025] In some example embodiments, the at least the capability of the first apparatus to learn or relearn the constellation may be reported to a second apparatus capable of receiving the signal, and the configuration may be determined in response to the reporting of the at least the capability.

[0026] In some example embodiments, the modulating of the DC component may reduce the DC component of the constellation.

[0027] In some example embodiments, the modulating of the DC component may reduce PAPR associated with transmitting signals modulated using the constellation.

[0028] In some example embodiments, the first apparatus is a user device and the second apparatus is a network device, and the means for determining the configuration may comprise means for obtaining the configuration for modulation of the DC component of the constellation.

[0029] In some example embodiments, the first apparatus is a network device and the second apparatus is a user device, and the means for determining the configuration comprises means for providing the configuration for modulation of the DC component of the constellation.

[0030] A second aspect provides a second apparatus comprising: means for determining a configuration for a modulation of a direct current, DC, component of a constellation, wherein the configuration comprises one or more parameters for configuring the modulation of a DC component of the constellation; means for receiving a modulated DC component of the constellation from a first apparatus; and means for demodulating a received signal from the first apparatus using the received modulated DC component of the constellation.

[0031] In some example embodiments, the one or more parameters may comprise at least one of: a coefficient for scaling the DC component; one or more first values for setting the DC component; one or more second values for scaling a pilot sequence of the constellation using the DC component; or one or more third values for shifting and/or rotating the DC component.

[0032] In some example embodiments, the second apparatus may further comprise: means for receiving from the first apparatus at least a capability of the first apparatus to modulate the DC component of the constellation.

[0033] In some example embodiments, the second apparatus is a network device and the first apparatus is a user device, and the means for determining the configuration may comprise means for providing the configuration for modulation of the DC component of the constellation.

[0034] In some example embodiments, the second apparatus is a user device and the first apparatus is a network device, and the means for determining the configuration comprises means for obtaining the configuration for modulation of the DC component of the constellation.

[0035] A third aspect provides a method, for example performed by a first apparatus, the method comprising: determining a configuration for modulation of a direct current, DC, component of a constellation, wherein the configuration comprises one or more parameters for configuring the modulation of a DC component of the constellation;

[0036] S

[0037] modulating the DC component of the constellation for a signal based on the configuration; and transmitting the modulated DC component of the constellation to a second apparatus.

[0038] In some example embodiments, the one or more parameters may comprise at least one of: a coefficient for scaling the DC component; one or more first values for setting the DC component; one or more second values for scaling a pilot sequence of the constellation using the DC component; or one or more third values for shifting and/or rotating the DC component.

[0039] In some example embodiments, the constellation may be a selected learned constellation of the first apparatus supporting a superimposed pilot, SR In some example embodiments, the method may further comprise reporting at least an indication of the selected learned constellation to the second apparatus, wherein the second apparatus is capable of receiving the signal.

[0040] In some example embodiments, the selected learned constellation may have a non-zero mean, NZM.

[0041] In some example embodiments, the method may further comprise reporting at least a capability of the first apparatus to modulate the DC component of the constellation to the second apparatus.

[0042] In some example embodiments, the configuration may be determined in response to the reporting of the at least the capability.

[0043] In some example embodiments, the method may further comprise: scaling the DC component based on at least one of: the coefficient for scaling the DC component; or the one or more second values for scaling the pilot sequence of the constellation.

[0044] In some example embodiments, the method may further comprise: shifting and/or rotating the DC component based on the one or more third values for shifting and/or rotating the DC component.

[0045] In some example embodiments, the method may further comprise: extracting the DC component from the constellation; means for modulating the extracted DC component based on the configuration; and applying the modulated extracted DC component to the constellation to provide an adapted constellation for the modulation of the signal.

[0046] In some example embodiments, a resource element, RE, allocated to the signal may comprise a data component with a first TX power and a pilot component with a second TX power.

[0047] In some example embodiments, the configuration may comprise at least a configuration for learning or relearning of the constellation, wherein said configuration comprises a plurality of modulation pilot sequences for modulating the DC component of the constellation.

[0048] In some example embodiments, the learned constellation may a zero mean, ZM or nonzero mean, NZM.

[0049] In some example embodiments, the method may further comprise: learning or relearning of the constellation with embedded modulated DC component based at least in part on the configuration.

[0050] In some example embodiments, the means for learning or relearning of the constellation may be configured to iteratively learn or relearn the constellation based at least in part on the plurality of modulation pilot sequences.

[0051] In some example embodiments, the configuration may further indicate at least one constraint for the learning or relearning of the constellation, and the learning or relearning of the constellation may further be based on the at least one constraint.

[0052] In some example embodiments, the at least one constraint comprises at least one of: an upper limit of estimated peak-to-average power ratio, PARR; an upper limit of the DC component; or a ratio between power allocated to data and power allocated to pilot symbols.

[0053] In some example embodiments, the method may further comprise: reporting at least a capability of the first apparatus to learn or relearn the constellation.

[0054] In some example embodiments, the at least the capability of the first apparatus to learn or relearn the constellation may be reported to a second apparatus capable of receiving the signal, and the configuration may be determined in response to the reporting of the at least the capability.

[0055] In some example embodiments, the modulating of the DC component may reduce the DC component of the constellation.

[0056] In some example embodiments, the modulating of the DC component may reduce PAPR associated with transmitting signals modulated using the constellation.

[0057] In some example embodiments, the first apparatus is a user device and the second apparatus is a network device, and determining the configuration may comprise obtaining the configuration for modulation of the DC component of the constellation.

[0058] In some example embodiments, the first apparatus is a network device and the second apparatus is a user device, and determining the configuration may comprise providing the configuration for modulation of the DC component of the constellation.

[0059] A fourth aspect provides a method, for example performed by a second apparatus, the method comprising: determining a configuration for a modulation of a direct current, DC, component of a constellation, wherein the configuration comprises one or more parameters for configuring the modulation of a DC component of the constellation; receiving a modulated DC component of the constellation from a first apparatus; and demodulating a received signal from the first apparatus using the received modulated DC component of the constellation.

[0060] In some example embodiments, the one or more parameters may comprise at least one of: a coefficient for scaling the DC component; one or more first values for setting the DC component; one or more second values for scaling a pilot sequence of the constellation using the DC component; or one or more third values for shifting and/or rotating the DC component.

[0061] In some example embodiments, the method may further comprise: receiving from the first apparatus at least a capability of the first apparatus to modulate the DC component of the constellation.

[0062] In some example embodiments, the second apparatus is a network device and the first apparatus is a user device, wherein determining the configuration may comprise providing the configuration for modulation of the DC component of the constellation.

[0063] In some example embodiments, the second apparatus is a user device and the first apparatus is a network device, wherein determining the configuration comprises obtaining the configuration for modulation of the DC component of the constellation.

[0064] A fifth aspect of provides a computer program comprising a set of instructions which, when executed on a first apparatus, is configured to cause the first apparatus to carry out a method comprising: determining a configuration for modulation of a direct current, DC, component of a constellation, wherein the configuration comprises one or more parameters for configuring the modulation of a DC component of the constellation; modulating the DC component of the constellation for a signal based on the configuration; and transmitting the modulated DC component of the constellation to a second apparatus.

[0065] The fifth aspect may also comprise any feature described in relation to the third aspect.

[0066] A sixth aspect of provides a computer program comprising a set of instructions which, when executed on a second apparatus, is configured to cause the second apparatus to carry out a method comprising: determining a configuration for a modulation of a direct current, DC, component of a constellation, wherein the configuration comprises one or more parameters for configuring the modulation of a DC component of the constellation; receiving a modulated DC component of the constellation from a first apparatus; and demodulating a received signal from the first apparatus using the received modulated DC component of the constellation.

[0067] The sixth aspect may also comprise any feature described in relation to the fourth aspect.

[0068] A seventh aspect of the invention provides a non-transitory computer-readable medium having stored thereon computer-readable code, which, when executed by at least one processor, causes the at least one processor to perform a method, comprising: determining a configuration for modulation of a direct current, DC, component of a constellation, wherein the configuration comprises one or more parameters for configuring the modulation of a DC component of the constellation; modulating the DC component of the constellation for a signal based on the configuration; and transmitting the modulated DC component of the constellation to an apparatus.

[0069] The seventh aspect may also comprise any feature described in relation to the third aspect.

[0070] An eighth aspect of the invention provides a non-transitory computer-readable medium having stored thereon computer-readable code, which, when executed by at least one processor, causes the at least one processor to perform a method, comprising: determining a configuration for a modulation of a direct current, DC, component of a constellation, wherein the configuration comprises one or more parameters for configuring the modulation of a DC component of the constellation; receiving a modulated DC component of the constellation from a first apparatus; and demodulating a received signal from the first apparatus using the received modulated DC component of the constellation.

[0071] The eighth aspect may also comprise any feature described in relation to the fourth 15 aspect.

[0072] A ninth aspect of the invention provides an apparatus, the apparatus having at least one processor and at least one memory having computer-readable code stored thereon which when executed controls the at least one processor to: determine a configuration for modulation of a direct current, DC, component of a constellation, wherein the configuration comprises one or more parameters for configuring the modulation of a DC component of the constellation; modulate the DC component of the constellation for a signal based on the configuration; and transmit the modulated DC component of the constellation to an apparatus.

[0073] The ninth aspect may also comprise any feature described in relation to the third aspect.

[0074] A tenth aspect of the invention provides an apparatus, the apparatus having at least one processor and at least one memory having computer-readable code stored thereon which when executed controls the at least one processor to: determine a configuration for a modulation of a direct current, DC, component of a constellation, wherein the configuration comprises one or more parameters for configuring the modulation of a DC component of the constellation; receive a modulated DC component of the constellation from a first apparatus; and demodulate a received signal from the first apparatus using the received modulated DC component of the constellation The tenth aspect may also comprise any feature described in relation to the fourth aspect.

[0075] An eleventh aspect provides a first apparatus comprising: means for obtaining a selection, from a set, of a constellation having a non-zero mean, NZM, and supporting a superimposed pilot, SP; means for modulating a direct current, DC, component of the selected NZM constellation; and means for applying the modulated DC component to the selected NZM constellation to provide an adapted NZM constellation for signal modulation.

[0076] In some example embodiments, the first apparatus may further comprise means for extracting, prior to the modulating, the DC component of the selected NZM constellation.

[0077] In some example embodiments, the first apparatus may further comprise means for encoding, prior to the modulating, an input signal for signal modulation.

[0078] In some example embodiments, the first apparatus may further comprise means for mapping, subsequent to the modulating, the modulated input signal to a plurality of resource elements, and means for modulating the mapped modulated input signal using orthogonal frequency division multiplexing, OFDM, or discrete Fourier transform-spreadfrequency division multiplexing, DFT-S-FDM.

[0079] In some example embodiments, the first apparatus may further comprise means for reporting at least an indication of the selected NZM constellation to a second apparatus capable of receiving signals modulated using the signal modulation.

[0080] In some example embodiments, the first apparatus may further comprise: means for reporting at least a capability of the first apparatus to modulate the DC component of the selected NZM constellation to a, or the, second apparatus capable of receiving signals modulated using the signal modulation.

[0081] In some example embodiments, the first apparatus may further comprise: means for determining a configuration for the modulating of the DC component of the selected NZM constellation in response to at least one of: reporting of the indication of the selected NZM constellation; or reporting of the capability of the of the first apparatus.

[0082] In some example embodiments, the selected constellation is a learned constellation of the first apparatus.

[0083] In some example embodiments, the first apparatus may further comprise: means for performing signal modulation using the adapted NZM constellation.

[0084] In some example embodiments, the first apparatus is a user device. The second apparatus may comprise a network device. The means for determining the configuration may comprise means for obtaining a configuration.

[0085] In some example embodiments, the first apparatus is a network device and the second apparatus is a user device. The means for determining the configuration comprises means for providing a configuration.

[0086] A twelfth aspect provides a second apparatus comprising: means for obtaining an indication of a selected non-zero mean, NZM, constellation; means for obtaining a modulated direct current, DC, component of the selected NZM constellation; and means for applying the modulated DC component to the selected NZM constellation to provide an adapted NZM constellation for signal demodulation.

[0087] In some example embodiments, the NZM constellation may support a superimposed pilot at a first apparatus.

[0088] In some example embodiments, the second apparatus may further comprise means for extracting, prior to the modulating, the DC component of the selected NZM constellation.

[0089] In some example embodiments, the second apparatus may further comprise means for demodulating the received signal using orthogonal frequency division multiplexing, OFDM, or discrete Fourier transform-spread-frequency division multiplexing, DFT-S-FDM, and means for de-mapping the demodulated signal from a plurality of resource elements.

[0090] In some example embodiments, the second apparatus may further comprise means for decoding, subsequent to the demapping, the received signal.

[0091] In some example embodiments, the indication is received in a report from a first apparatus.

[0092] In some example embodiments, the second apparatus may further comprise means for receiving at least a capability of a first apparatus to modulate the DC component of the selected NZM constellation.

[0093] In some example embodiments, the second apparatus may further comprise means for determining a configuration for the modulating of the DC component of the selected NZM constellation in response to at least one of: the received indication from the first apparatus; or the received capability over the first apparatus.

[0094] S

[0095] In some example embodiments, the selected NZM constellation is a learned constellation of the first apparatus.

[0096] In some example embodiments, the second apparatus may further comprise means for receiving a signal from a first apparatus, and means for performing signal demodulation using the adapted NZM constellation.

[0097] In some example embodiments, the second apparatus is a network device. The first apparatus may comprise a user device. The means for determining the configuration may comprise means for providing a configuration.

[0098] In some example embodiments, the second apparatus is a user device. The first apparatus may comprise a user device. The means for determining the configuration may comprise means for obtaining a configuration.

[0099] A thirteenth aspect provides a method, for example performed by a first apparatus, the method comprising: obtaining a selection, from a set, of a constellation having a nonzero mean, NZM, and supporting a superimposed pilot, SP; modulating a direct current, DC, component of the selected NZM constellation; and applying the modulated DC component to the selected NZM constellation to provide an adapted NZM constellation for signal modulation.

[0100] In some example embodiments, the method further comprise extracting, prior to the modulating, the DC component of the selected NZM constellation.

[0101] In some example embodiments, the method may further comprise encoding, prior to the modulating, an input signal for signal modulation.

[0102] In some example embodiments, the method may further comprise mapping, subsequent to the modulating, the modulated input signal to a plurality of resource elements, and modulating the mapped modulated input signal using orthogonal frequency division multiplexing, OFDM, or discrete Fourier transform-spread-frequency division multiplexing, DFT-S-FDM.

[0103] In some example embodiments, the method may further comprise reporting at least an indication of the selected NZM constellation to a second apparatus capable of receiving signals modulated using the signal modulation.

[0104] In some example embodiments, the method may further comprise: reporting at least a capability of the first apparatus to modulate the DC component of the selected NZM constellation to a, or the, second apparatus capable of receiving signals modulated using the signal modulation.

[0105] In some example embodiments, the method may further comprise: determining a configuration for the modulating of the DC component of the selected NZM constellation in response to at least one of: reporting of the indication of the selected NZM constellation, or reporting of the capability of the of the first apparatus.

[0106] In some example embodiments, the selected constellation is a learned constellation of the first apparatus.

[0107] In some example embodiments, the method may further comprise performing signal modulation using the adapted NZM constellation.

[0108] In some example embodiments, the first apparatus is a user device. The second apparatus may comprise a network device. The determining the configuration may comprise obtaining a configuration.

[0109] In some example embodiments, the first apparatus is a network device. The second apparatus may comprise a user device. The determining the configuration may comprise providing a configuration.

[0110] A fourteenth aspect provides a method, for example performed by a second apparatus, the method comprising: obtaining an indication of a selected non-zero mean, NZM, constellation; obtaining a modulated direct current, DC, component of the selected NZM constellation; and applying the modulated DC component to the selected NZM constellation to provide an adapted NZM constellation for signal demodulation.

[0111] S

[0112] In some example embodiments, the NZM constellation may support a superimposed pilot at a first apparatus.

[0113] In some example embodiments, the method may further comprise extracting, prior to the modulating, the DC component of the selected NZM constellation.

[0114] In some example embodiments, the method may further comprise demodulating the received signal using orthogonal frequency division multiplexing, OFDM, or discrete Fourier transform-spread-frequency division multiplexing, DFT-S-FDM, and de-mapping the demodulated signal from a plurality of resource elements.

[0115] In some example embodiments, the method may further comprise decoding, subsequent to the demapping, the received signal.

[0116] In some example embodiments, the indication is received in a report from a first apparatus.

[0117] In some example embodiments, the method may further comprise receiving at least a capability of a first apparatus to modulate the DC component of the selected NZM constellation.

[0118] In some example embodiments, the method may further comprise determining a configuration for the modulating of the DC component of the selected NZM constellation in response to at least one of: the received indication from the first apparatus; or the received capability over the first apparatus.

[0119] In some example embodiments, the selected NZM constellation is a learned constellation of the first apparatus.

[0120] In some example embodiments, the method may further comprise receiving a signal from a first apparatus, and performing signal demodulation using the adapted NZM constellation.

[0121] In some example embodiments, the second apparatus is a network device. The first apparatus may comprise a user device. The determining the configuration may comprise providing a configuration.

[0122] In some example embodiments, the second apparatus is a user device. The first apparatus may comprise a user device. The determining the configuration may comprise obtaining a configuration A fifteenth aspect of provides a computer program comprising a set of instructions which, when executed on a first apparatus, is configured to cause the first apparatus to carry out a method comprising: obtaining a selection, from a set, of a constellation having a non-zero mean, NZM, and supporting a superimposed pilot, SP; modulating a direct current, DC, component of the selected NZM constellation; and applying the modulated DC component to the selected NZM constellation to provide an adapted NZM constellation for signal modulation.

[0123] The fifteenth aspect may also comprise any feature described in relation to the thirteenth aspect.

[0124] A sixteenth aspect of provides a computer program comprising a set of instructions which, when executed on a second apparatus, is configured to cause the second apparatus to carry out a method comprising: obtaining an indication of a selected non-zero mean, NZM, constellation; obtaining a modulated direct current, DC, component of the selected NZM constellation; and applying the modulated DC component to the selected NZM constellation to provide an adapted NZM constellation for signal demodulation.

[0125] The sixteenth aspect may also comprise any feature described in relation to the fourteenth aspect.

[0126] A seventeenth aspect of the invention provides a non-transitory computer-readable medium having stored thereon computer-readable code, which, when executed by at least one processor, causes the at least one processor to perform a method, comprising: obtaining a selection, from a set, of a constellation having a non-zero mean, NZM, and supporting a superimposed pilot, SP; modulating a direct current, DC, component of the selected NZM constellation; and applying the modulated DC component to the selected NZM constellation to provide an adapted NZM constellation for signal modulation.

[0127] The seventeenth aspect may also comprise any feature described in relation to the thirteenth aspect.

[0128] An eighteenth aspect of the invention provides a non-transitory computer-readable medium having stored thereon computer-readable code, which, when executed by at least one processor, causes the at least one processor to perform a method, comprising: obtaining an indication of a selected non-zero mean, NZM, constellation; obtaining a modulated direct current, DC, component of the selected NZM constellation; and applying the modulated DC component to the selected NZM constellation to provide an adapted NZM constellation for signal demodulation.

[0129] The eighteenth aspect may also comprise any feature described in relation to the fourteenth aspect.

[0130] A nineteenth aspect of the invention provides an apparatus, the apparatus having at least one processor and at least one memory having computer-readable code stored thereon which when executed controls the at least one processor to: obtain a selection, from a set, of a constellation having a non-zero mean, NZM, and supporting a superimposed pilot, SP; modulate a direct current, DC, component of the selected NZM constellation; and apply the modulated DC component to the selected NZM constellation to provide an adapted NZM constellation for signal modulation.

[0131] The nineteenth aspect may also comprise any feature described in relation to the thirteenth aspect.

[0132] A twentieth aspect of the invention provides an apparatus, the apparatus haying at least one processor and at least one memory having computer-readable code stored thereon which when executed controls the at least one processor to: obtain an indication of a selected non-zero mean, NZM, constellation; obtain a modulated direct current, DC, component of the selected NZM constellation; and apply the modulated DC component to the selected NZM constellation to provide an adapted NZM constellation for signal demodulation.

[0133] The twentieth aspect may also comprise any feature described in relation to the fourteenth aspect.

[0134] Brief Description of the Drawings

[0135] The invention will now be described, by way of non-limiting example, with reference to the accompanying drawings, in which: FIG. 1 illustrates a first constellation; FIG. 2 illustrates a second constellation; FIG. 3 illustrates a third constellation; FIG. 4 illustrates a fourth constellation; FIG. 5 illustrates a system comprising a first apparatus and a second apparatus; FIG. 6A is a flow diagram showing operations in accordance with one or more example embodiments; FIG. 63 is a flow diagram showing operations in accordance with one or more other example embodiments; FIG. 7 illustrates a system comprising a first apparatus and a second apparatus in accordance with one or more example embodiments; FIG. 8A illustrates a fifth constellation that may be generated in accordance with one or more example embodiments; FIG. 83 illustrates a sixth constellation that may be generated in accordance with one or more example embodiments; FIG. 9 illustrates seventh to tenth constellations that may be generated in accordance with one or more example embodiments; FIG. 10 is a signal flow diagram in accordance with one or more example embodiments; FIG. 11 is a further flow diagram showing operations in accordance with one or more other example embodiments; FIG. 12 is a further flow diagram showing operations in accordance with one or more other example embodiments; FIG. 13 illustrates an apparatus which may be configured to operate in accordance with one or more example embodiments; and FIG. 14 illustrates a non-transitory computer-readable medium for storing computer-readable instructions for causing the FIG. 13 apparatus to operate in accordance with one or more example embodiments.

[0136] Detailed Description

[0137] Example embodiments relate generally to constellations for signal modulation. Example embodiments relate to an apparatus, method and computer program for modulation of a direct current, DC, component of a constellation.

[0138] Communications systems such as 4G LTE, SG use, or in the case of 6G will use, digital modulation and demodulation schemes for transmitting and receiving data. Example modulation schemes include, but are not limited to, Quadrature Phase-Shift Keying (QPSK) and Quadrature Amplitude Modulation (QAM) schemes. Digital modulation may involve the use of two carrier signals, referred to as in-phase (I) and quadrature (Q) signals or components, which are mixed with an input signal using an oscillator, wherein the Q signal or component undergoes a 90 degrees phase shift relative to the I signal or component. The I/Q signals may then be summed to provide a combined signal output which may undergo further processing before being transmitted over an air interface.

[0139] Most digital modulation schemes involve a discrete number of symbols which are used to convey information. The symbols may be mapped to a set of magnitude and phase values on an I/Q plane, which are referred to as constellation points or, collectively, a constellation.

[0140] Digital modulation schemes with greater numbers of constellation points may transmit more information per symbol and, the more symbols there are, the greater the number of bits a single symbol can represent. For example, QPSK comprises four constellation points {00, 01, 10 or 11} and can transmit two bits per symbol. For example, QAM may use a greater number of constellation points depending on the order For example, 16-QAM uses sixteen constellation points, 64-QAM uses sixty four constellation points and so on. A receiver of the digitally modulated signal may, with knowledge of the constellation points, perform the reverse process to recover the transmitted signal.

[0141] It follows that how data is modulated can be represented by a set of data or information referred to as a constellation. A constellation can be represented as a two-dimensional scatter plot, or constellation diagram, which comprises the I/Q plane.

[0142] Digital modulation schemes may use pilot components, sometimes referred to as pilot symbols or pilot tones, the pattern of which in the time and frequency domain is known to both the transmitter and receiver for performing channel estimation.

[0143] Some digital modulation schemes may use superimposed pilots, SPs, wherein both the data and pilot components are transmitted in most (possibly all) resource elements at respective transmit powers. This may allow the transmitter, for example a user equipment (UE), to send the SPs at a reduced power alongside data and potentially throughout the entire uplink (UL) data slots. Advantageously, this provides more orthogonal pilot components for channel estimation and decreases the possibility of pilot reuse among different UEs. However, this may also induce the data and SPs to correlate and result in cross-interference.

[0144] It has been proposed to use machine learning (ML) techniques in connection with digital modulation processes.

[0145] One potential use case is for user devices to learn one or more constellations to optimise one or more aspects of data transmission, for example to improve data throughput, reduce interference and so on. For example, the one or more learned constellations may also natively embed SPs.

[0146] ML in this context may comprise use of deep learning, use of artificial neural networks (ANNs) and/or other forms of processing system or systems whereby a set of training data may be used to generate a learned model which may be used to provide output data, e.g., a constellation, in response to input data.

[0147] An enabler for ML in this context is by means of allowing the apparatus to derive a nonzero mean (NZM) constellation of a given order NZM constellations may however suffer from a higher peak-to-average power ratio (PAPR) compared with zero-mean (ZM) constellations. Higher PAPR may lead to increased complexity of analog-to-digital converters (ADC) and digital-to-analog converters (DAC) and may also reduce efficiency of power amplifiers at the transmitter and receiver ends.

[0148] FIG. 1 illustrates a QPSK constellation 100 with a ZM which has an average PAPR (of Orthogonal Frequency Division Multiplexing (OFDM) symbols generated using said constellation) of 8.71 dB.

[0149] FIG. 2 illustrates a learned QPSK constellation 200 of the same size, but with NZM. It will be seen that the mean DC component is 0.13+0.14j and the average PAPR is 15.66 dB, which is almost 7 dB higher than the FIG. 1 constellation 100.

[0150] FIG. 3 illustrates a 64-QAM constellation 300 with ZM which has an average PAPR of 8.72 dB.

[0151] FIG. 4 illustrates a learned 64-QAM constellation 400 of the same size, but with NZM. It will be seen that the mean DC component is 0.10+0.01j and the average PAPR is 10.66 dB, which is almost 2 dB higher than the FIG. 3 constellation 300. We therefore observe a smaller increase in PAPR compared with the learned QPSK constellation 200 because of the smaller DC component.

[0152] Example embodiments relate to modulation of a DC component of a constellation, which may be based on a configuration.

[0153] The mean of a constellation is the DC component.

[0154] The constellation may be a ZM or NZM constellation, although example embodiments may focus on NZM constellations.

[0155] The modulation may be for reducing the DC component which may reduce PAPR of an UL or downlink (DL) signal transmitted using the modulated constellation.

[0156] FIG. 5 illustrates a system 500 comprising a first apparatus 510 and a second apparatus 530 respectively acting as a transmitter and a receiver and wherein the first apparatus transmits signals to the second apparatus by means of an air interface 501. Communications over the air interface 501 may be by means of a radio access technology (RAT) that both the first apparatus 510 and the second apparatus 530 are configured to support.

[0157] The first apparatus 500 may comprise, in some examples, a user device which may comprise a smartphone, tablet computer, laptop computer, personal computer, vehicle, digital assistant, wearable computer or similar.

[0158] The second apparatus 530 may comprise, in some examples, a network node or network device which may comprise an NodeB, enhanced NodeB (eNB), gNodeB (gNB), a transmission and reception point (TRP), relay or similar.

[0159] In other examples, the first apparatus 500 may comprise a network node or network device and the second apparatus 530 may comprise a user device.

[0160] The above examples are not intended to be limiting.

[0161] The first apparatus 500 may be required to transmit data in the form of input bits 512 to the second apparatus 530.

[0162] In the case that the first apparatus 500 is a user device and the second apparatus 530 is a network node, e.g., gNB, the data is transmitted as one or more UL signals. In the case that the first apparatus 500 is a network node or network device, e.g., gNB and the second apparatus 530 is a user device, the data is transmitted as one or more DL signals. The following examples assume the former scenario, i.e., transmission and reception of UL signals, but it should be appreciated that example embodiments may also apply to transmission and reception of DL signals.

[0163] In accordance with known methods, the inputs bits 512 may be encoded by an encoder 514 and modulated by a modulator 516 according to, or using, a constellation, for example a QPSK or QAM constellation of a suitable order. The modulated bits may be mapped to resource elements (RE) by a RE mapper 517 and then further modulated using, for example, OFDM (or Discrete Fourier Transform -spread -Frequency Division Multiplexing, DFT-S-FDM) by an OFDM/DFT-s-FDM modulator 520. A resulting UL signal 522 may then be transmitted via an antenna 524 over the air interface 501.

[0164] At the second apparatus 530, a received UL signal 532 (i.e., a received version of the uplink signal 522) is received via an antenna 528 and may undergo complementary processing.

[0165] For example, the received UL signal 532 may be processed by an OFDM/DFT-s-FDM demodulator 534, a RE de-mapper 536 and a demodulator 538 to recover an estimate 540 of the input bits 512. The demodulator 538 may perform demodulation based on knowledge of the constellation used by the modulator 516 of the first apparatus 510.

[0166] Some example embodiments relate to operations at the first apparatus 510 and, in particular, operations at (or associated with) the modulator 516. Some other example embodiments relate to operations at the second apparatus 530 and, in particular, operations at (or associated with) the demodulator 538.

[0167] FIG. 6A is a flow diagram showing operations 600 that may be performed by one or more example embodiments. The operations 600 may be performed by hardware, software, firmware or a combination thereof. The operations 600 may be performed by one, or respective, means, a means being any suitable means such as one or more processors or controllers in combination with computer-readable instructions provided on one or more memories. The operations 600 may, for example, be performed by the first apparatus 510, for example by the modulator 516 of the first apparatus or a module associated with the modulator.

[0168] A first operation 601 may comprise determining a configuration for modulation of a DC component of a constellation, wherein the configuration comprises one or more parameters for configuring the modulation of a DC component of the constellation.

[0169] The term determining may comprise obtaining or receiving. For example, the configuration may be obtained or received from a different apparatus, for example, the second apparatus 530 in the FIG. 5 example.

[0170] For example, the configuration may comprise a set of data transmitted using certain time and frequency resources that the receiving apparatus, for example the first apparatus 510 in the FIG. 5 example, knows is associated with constellation modulation and uses the configuration to perform one or more further operations.

[0171] A second operation 602 may comprise modulating the DC component of the constellation for a signal based on the determined (obtained or received) configuration.

[0172] A third operation 603 may comprise transmitting the modulated DC component of the constellation to a second apparatus.

[0173] Example embodiments will be described in further detail.

[0174] As will be described below, the one or more parameters may comprise at least one of: a coefficient for scaling the DC component, one or more first values for setting the DC component, one or more second values for scaling a pilot sequence of the constellation, or one or more third values for shifting and/or rotating the DC component.

[0175] The one or more parameters may further comprise an indication of a modulation type or category, for example QPSK or QAM.

[0176] In an example embodiment, the first apparatus 510 may be configured to learn one or more constellations.

[0177] The first apparatus 510 may be configured to learn the one or more constellations independently of the second apparatus 530 or, alternatively, with assistance from the second apparatus, as will be described later on.

[0178] The one or more learned constellations may comprise NZM constellations supporting a SP. A NZM constellation has a NZM DC component.

[0179] The one or more learned NZM constellations may allocate some signal energy to pilot symbols on most or all Res for an UL signal as explained above. For example, a RE allocated to the UL signal may comprise a data component with a first transmit (TX) power and a pilot component with a second TX power.

[0180] The one or more learned constellations may comprise QPSK constellations or QAM constellations of any order, although this is not intended to be limiting.

[0181] FIG. 6B is a flow diagram showing operations 610 that may be performed by one or more example embodiments. The operations 610 may be performed by hardware, software, firmware or a combination thereof. The operations 610 may be performed by one, or respective, means, a means being any suitable means such as one or more processors or controllers in combination with computer-readable instructions provided on one or more memories. The operations 610 may, for example, be performed by the demodulator 538 of the second apparatus 530 or a module associated with the demodulator.

[0182] A first operation 611 may comprise determining a configuration for modulation of a DC component of a constellation, wherein the configuration comprises one or more parameters for configuring the modulation of a DC component of the constellation.

[0183] The term determining may comprise generating and/or transmitting or sending. For example, the configuration may be transmitted to a different apparatus, for example, the first apparatus 510 in the FIG. 5 example.

[0184] For example, the configuration may comprise a set of data transmitted using certain time and frequency resources that the receiving apparatus, for example the first apparatus 510 in the FIG. 5 example, knows is associated with constellation modulation.

[0185] A second operation 612 may comprise receiving a modulated DC component of the constellation from a first apparatus, for example the first apparatus 510 in the FIG. 5 example, which may be capable of transmitting a signal from the first apparatus using the received modulated DC component of the constellation.

[0186] A third operation 613 may comprise demodulating a received signal from the first apparatus using the received modulated DC component of the constellation.

[0187] FIG. 7 illustrates the first apparatus 510 and the second apparatus 530 when configured in accordance with one or more example embodiments.

[0188] The modulator 516 or other module associated with the modulator, may be configured to determine, for example obtain, a constellation from a set of one or more learned constellations 702 for, for example, UL signal modulation of input bits 512.

[0189] For example, the obtained constellation may be a selected constellation, and the selection may be performed by the second apparatus 530 or other node and signaled to the first apparatus 510 or the selection may be performed by the first apparatus and signaled to the second apparatus. References hereinafter to "selected constellation" refers to a constellation selected by any of the First apparatus 510, the second apparatus 530 or a further apparatus.

[0190] S

[0191] The set of one or more learned constellations 702 may be obtained or derived using a ML module 704, for example a processing means implementing one or more ANNs.

[0192] The first apparatus 510 may be configured to report information to the second apparatus 530 using one or more messages. For example, in the case where the first apparatus 510 selects the constellation, the First apparatus may report an indication 706 of the selected learned constellation and a capability of the first apparatus to modulate a DC component of the selected learned constellation. Alternatively, the First apparatus 510 may report an indication of the set of one or more learned constellations 702 to the second apparatus 530 and said capability, and the second apparatus may select a learned constellation from the set which it indicates back to the First apparatus.

[0193] The first apparatus 510 may responsively determine, for example obtain or receive, a configuration 708 from the second apparatus 530. The configuration 708 may comprise the one or more parameters for modulating the DC component of the selected learned constellation, examples of which are given above.

[0194] The first apparatus 510, in particular the modulator 516 or an associated module, may modulate the DC component of the selected learned constellation based on the configuration 708 to provide an adapted version of the selected learned constellation.

[0195] The first apparatus 510 may transmit the modulated DC component of the selected learned constellation to the second apparatus 530.

[0196] The first apparatus 510, in particular the modulator 516 or the associated module, may modulate the input bits 512 using the adapted version of the selected learned constellation for transmission as the UL signal over the air interface 501.

[0197] The second apparatus 530 may comprise a neural demodulator 538 configured to apply the received modulated DC component of the selected learned constellation, indicated by reference numeral 710, to provide an adapted version of the selected learned constellation 710.

[0198] The neural demodulator 538 may thereafter demodulate the received UL signal 532 based on the adapted version of the selected learned constellation 710.

[0199] In an example, the one or more parameters of the constellation may be used for post-processing of the selected learned constellation.

[0200] As described above, the configuration may comprise a coefficient for scaling the DC component.

[0201] For example, the one or more parameters of the configuration may comprise a coefficient for scaling down the DC component (the mean of the DC component) of the selected learned constellation by a rescaling factor. The rescaling factor may be expressed in any suitable form.

[0202] FIG. 8A illustrates a first scaled-down QPSK constellation 810 based on the FIG. 2 NZM constellation 200 with SR The mean DC component is 0.05+0.05j and the average PAPR is 9.08 dB.

[0203] FIG. 8B illustrates a second scaled-down QPSK constellation 820 based on the FIG. 2 NZM constellation 200 with SR The mean DC component is 0.03-0.03j and the average PAPR is 8.72 dB.

[0204] Note that after scaling down the DC component, the PAPR of the FIG. 8A and 88 QPSK constellations 810, 820 is very close to 8.71 dB PAPR obtained for the FIG. 1 ZM QPSK constellation 100.

[0205] In another example, the one or more parameters of the configuration may comprise one or more first values for setting the DC component of the selected learned constellation. The one or more first values may set the real and/or imaginary values of the constellation points for reducing the DC component (the mean of the DC component).

[0206] The one or more values may be expressed in any suitable form.

[0207] In another example embodiment, the one or more parameters of the configuration may comprise one or more second values for scaling a pilot sequence of the selected learned NZM constellation using the DC component.

[0208] The one or more second values may comprise a known or coordinated sequence between the first apparatus 510 and the second apparatus 530 for scaling the pilot sequence of the selected learned constellation.

[0209] For example, the first apparatus 510 may learn a constellation Cx with size 64 while the DC component of the pilot sequence of the constellation Cx is modulated with the one or more second values to provide the scaling.

[0210] For example, consider a DC component of a selected NZM constellation as a+jb.

[0211] The DC component of the selected learned NZM constellation may be modulated, similar to QPSK modulation, by scaling the pilot sequence, for example based on the power of the learnt DC component. The SP at a given RE may comprise one of the following entries: -42+62 1,---j4 -4+4vz - (1) v2 v2'v2 vz' vz vz' Alternatively, or additionally, the DC component of the selected learned NZM constellation may be modulated using one or more third values for shifting and/or rotating the DC component. The one or more third values may be a modulating sequence.

[0212] For example, the SP at a given RE allocated to UL signals may comprise one of the following entries: (a + b) [1, , -1, -1 j] (2) FIG. 9 illustrates an impact of modulating the DC component of the selected learned NZM constellation by rotating the DC component over four different REs allocated to UL signals.

[0213] It will be seen that the final constellation points for the respective REs depend on the assigned pilot value for the particular RE. Although the original NZM constellation, illustrated in FIG. 4, has a DC component (mean) 0.1+0.01j resulting in an average PAPR of 10.66 dB, the modulation of the DC component by rotating the DC component can reduce the average PAPR to 8.75 dB and 8.73 dB respectively. Note that OFDM signals using a 64-QAM ZM constellation have an average PAPR of 8.74 dB.

[0214] As mentioned above, for methods that involve scaling the pilot sequence and/or shifting and/or rotating the DC component, there should be co-ordination between the first apparatus 510 and the second apparatus 530. In other words, the sequence of the second and/or third values should be known to both of the first apparatus 510 and the second apparatus 530 so that the second apparatus can modulate the DC component of the selected learned constellation and demodulate the modulated data prior to channel estimation.

[0215] Thus, the second apparatus 530 may signal, as part of the configuration, which sequence of second and/or third values should be used by the first apparatus 510 for the current input bits 512.

[0216] FIG. 10 illustrates a signal flow diagram between a user equipment (UE) 1001 as an example of the first apparatus 510 and a gNB 1002 as an example of the second apparatus 530.

[0217] The UE 1001 may determine, i.e., select or receive selection of, one or more learned constellations. It may be assumed that one learned NZM constellation supporting an SP is selected.

[0218] The UE 1001 may report at least an indication of the selected learned NZM constellation to the gNB 902, or an indication of a set of learned constellations to the gNB 902 which selects the learned constellation, in a first signal or message 1011.

[0219] In some example embodiments, the UE 1001 may also report a capability of the UE to modulate the DC component of the selected NZM constellation.

[0220] The gNB 1002 may responsively determine a post-learning method for the selected learned NZM constellation in an operation 1012.

[0221] For example, the post-learning method may comprise one of the above examples.

[0222] The gNB 1002 may indicate the post-learning method in a configuration comprising one or more parameters for modulating the DC component of the selected NZM constellation.

[0223] The configuration may be transmitted to the UE 1001 in a second signal or message 1013.

[0224] The UE 1001 may apply the post-learning method indicated by the configuration to obtain an adapted NZM constellation in an operation 1014. For example, applying the post-learning method 1014 may comprise at least modulating the DC component of the selected learned constellation based on the configuration to provide the adapted NZM constellation, which may be in accordance with one of the above examples.

[0225] In some example embodiments, prior to modulating the DC component, the DC component may be extracted or isolated to enable said modulating in isolation from other components.

[0226] The UE 1001 may transmit the modulated DC component to the gNB 1002 in a third signal or message 1015.

[0227] The UE 1001 may generate an UL signal using the adapted NZM constellation in an operation 1016.

[0228] For example, the UE 1001 may modulate the input bits 512 to provide the UL signal 522 using the adapted NZM constellation.

[0229] The UE 1001 may transmit the UL signal to the gNB 1002 in an operation 1017.

[0230] The gNB 1002 may apply the received modulated DC component to the selected constellation to provide its own adapted version of the selected NZM constellation, which is used to demodulate and decode data in the received UL signal in an operation 1018.

[0231] In the case that the gNB 1002 is to transmit a DL signal to the UE 1001, the gNB may determine, for example generate or obtain, a configuration for modulating a DC component of the selected NZM constellation. The gNB 1002 may then perform an operation similar to operation 1014 to transmit the modulated DC component in a signal or message to the UE 1001. The gNB may generate an adapted NZM constellation comprising the modulated DC component and modulates input bits to provide the DL signal using the adapted NZM constellation. The gNB 1002 may transmit the DL signal to the UE 1001. The UE 1001 may apply the received modulated DC component to the selected NZM constellation at its end, which is used to demodulate and decode data in the received DL signal.

[0232] In other examples, as an alternative or in addition to the post-learning approach, the first apparatus 510 (e.g., the UE 1001) may be configured to learn or relearn one or more constellations based at least in part on the determined configuration.

[0233] For example, the first apparatus 510 may learn one or more new constellations or may relearn one or more existing constellations, which may comprise at least one of the set of one or more learned constellations 702 described in the above examples.

[0234] The configuration may be received from the second apparatus 530, or other remote node or apparatus.

[0235] The configuration may comprise at least a configuration for learning or relearning of one or more ZM or NZM constellations, wherein said configuration comprises a plurality of modulation pilot sequences for modulating the DC component of the one or more ZM or NZM constellations. The ZM or NZM constellations may support an SP.

[0236] The first apparatus 510 may iteratively learn or relearn the one or more ZM or NZM constellations based at least in part on the plurality of modulation pilot sequences.

[0237] Similar to the example described with reference to FIG. 7, the first apparatus 510 may be configured to report at least a capability of the first apparatus to learn or relearn the one or more ZM or NZM constellations. The first apparatus 510 may report at least said capability to, for example, the second apparatus 530 which is capable of receiving UL signals modulated using the UL signal modulation. The first apparatus 510 may receive said configuration from, for example, the second apparatus 530 in response to the reporting of the at least the capability.

[0238] The first apparatus 510 and second apparatus 530 may therefore agree on, and use, the same configuration, at least comprising the same plurality of modulation pilot sequences for the learning or relearning of the one or more ZM or NZM constellations. The second apparatus 530 may perform the same learning process as described above using the same plurality of modulation pilot sequences.

[0239] The modulation pilot sequences may, for example, be similar to existing pilot patterns and/ or produced using a random number generator with predefined seed.

[0240] In some example embodiments, the learned or relearned constellation may be defined as a sum of the constellation points and a parameterized vector may be used to produce modulation sequences of arbitrary length. For example, an additional term may be produced by multiplying a real-valued variable, for example defining the magnitude of the SP, and a random sequence of complex QPSK symbols or other sequences on a unit circle. This effectively provides a modulated pilot sequence.

[0241] In some example embodiments, said configuration may further indicate at least one constraint, wherein the learning or relearning is further based on the at least one constraint.

[0242] The process of iteratively learning or relearning of the one or more ZM or NZM constellations may therefore aim to minimize a function, for example a loss function, based on the at least one constraint. When the loss function converges to a predetermined minimum value, the one or more ZM or NZM constellations may be considered final.

[0243] Said configuration may further indicate the at least one constraint.

[0244] The at least one constraint may, for example, comprise at least one of: a preferred power of SP, an upper limit of estimated PAPR, an upper limit of the DC component or a ratio between power allocated to data and power allocated to pilot symbols.

[0245] In some example embodiments, the configuration may configure the first apparatus 510 to learn or relearn the one or more ZM or NZM constellations of a size {01, ..., ON} i.e., corresponding to the number of bits mapped to each constellation point.

[0246] In some example embodiments, said configuration may further comprise at least one of the one or more first values for setting the DC component, one or more second values for scaling a pilot sequence of the constellation or one or more third values for shifting and/or rotating the DC component. In this way, the learning or relearning of the one or more ZM or NZM constellations may be further based on, for example, at least one of these values.

[0247] In such a joint-learning process, the ZM or NZM constellation is learned natively by the first apparatus 510 and the second apparatus 530 with modulated DC component and SP without either having to modulate the DC component as part of a post-learning operation.

[0248] In all such examples, the modulating of the DC component of the selected constellation may reduce the DC component and/or reduce PAPR associated with transmitting UL or DL signals modulated using the selected constellation.

[0249] FIGs. 11 and 12 are flow diagrams showing operations 1100, 1200 that may be performed by a transmitter and receiver respectively.

[0250] The operations 1100, 1200 may be performed by hardware, software, firmware or a combination thereof. The operations 1100, 1200 may be performed by one, or respective, means, a means being any suitable means such as one or more processors or controllers in combination with computer-readable instructions provided on one or more memories.

[0251] With reference to FIG. 11, the operations 1100 may, for example, be performed by the modulator 516 of the first apparatus 510 shown in FIG. 7 or a module associated with the modulator.

[0252] A first operation 1101 may comprise selecting, for example from a set of constellations, a constellation.

[0253] The selected constellation may be a ZM or NZM constellation.

[0254] A second operation 1102 may comprise modulating a DC component of the selected constellation.

[0255] The second operation 1202 may be performed using any of the options described above, for example based on a configuration comprising the one or more parameters and/or as part of a joint learning or relearning method.

[0256] A third operation 1103 may comprise applying the modulated DC component to the selected constellation to provide an adapted constellation for signal modulation.

[0257] In some example embodiments, a further operation (not shown) may comprise extracting, prior to the second operation 1102, the DC component of the selected NZM constellation, wherein the modulating of the DC component is performed on the extracted DC component which may be re-inserted or re-applied. This further operation may not be required in the case of joint learning or relearning of the selected constellation, as it is sufficient to simply modulate with the one or more modulation sequences.

[0258] In some example embodiments, a further operation (not shown) may comprise transmitting the modulated DC component to a second apparatus, for example the second apparatus 530 shown in FIG. 7. In some example embodiments, a further operation (not shown) may comprise modulating a signal, for example an UL or DL signal, using the adapted constellation.

[0259] With reference to FIG. 12, the operations 1200 may, for example, be performed by the neural demodulator 538 of the second apparatus 530 shown in FIG. 7 or a module associated with the neural demodulator.

[0260] A first operation 1201 may comprise obtaining an indication of the selected constellation.

[0261] The indication may be obtained from the first apparatus 510, the second apparatus 530 or another apparatus.

[0262] A second operation 1202 may comprise obtaining a modulated DC component of the selected constellation.

[0263] The second operation 1202 may be performed using any of the options described above, for example based on a configuration comprising the one or more parameters and/or as part of a joint learning or relearning method. The obtaining may comprise receiving or generating.

[0264] A third operation 1203 may comprise applying the modulated DC component to the selected constellation to provide an adapted constellation for signal demodulation.

[0265] In some example embodiments, a further operation (not shown) may comprise extracting, prior to the second operation 1202, the DC component of the selected NZM constellation, wherein the obtained DC component (whether received or generated) may be used in place of the extracted DC component. This further operation may not be required in the case of joint learning or relearning of the selected constellation, as it is sufficient to simply modulate with the one or more modulation sequences.

[0266] In all above examples, it will be appreciated that a transmitting apparatus, for example the first apparatus 510, may reduce a DC component of a constellation, for example a NZM constellation supporting a SP, which may have certain advantages in terms of reducing PAPR for UL (or DL) signals transmitted using the constellation with reduced DC component. Note, however, in some cases if the DC component is very small, the second apparatus 530 may request that the DC component be increased to ease channel estimation by the second apparatus.

[0267] Example Apparatus

[0268] FIG. 13 illustrates an example apparatus 1300 capable of supporting at least some embodiments. Illustrated is a device 1300, which may comprise the first apparatus 510 or the second apparatus 530 of FIG. 7. Comprised in device 1300 is a processor 1310, which may comprise, for example, a single-or multi-core processor wherein a single-core processor comprises one processing core and a multi-core processor comprises more than one processing core. The processor 1310 may comprise, in general, a control device. The processor 1310 may comprise more than one processor. The processor 1310 may be a control device. The processor 1310 may comprise at least one Application-Specific Integrated Circuit, ASIC. The processor 1310 may comprise at least one Field-Programmable Gate Array, FPGA. The processor 1310 may be means for performing method steps in device 1300. The processor 1310 may be configured, at least in part by computer instructions, to perform actions.

[0269] A processor may comprise circuitry, or be constituted as circuitry or circuitries, the circuitry or circuitries being configured to perform phases of methods in accordance with embodiments described herein. As used in this application, the term "circuitry" may refer to one or more or all of the following: (a) hardware-only circuit implementations, such as implementations in only analog and/or digital circuitry, and (b) combinations of hardware circuits and software, such as, as applicable: (i) a combination of analog and/or digital hardware circuit(s) with software/firmware and (ii) any portions of hardware processor(s) with software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, or a device configured to control the functioning thereof, to perform various functions) and (c) hardware circuit(s) and or processor(s), such as a microprocessor(s) or a portion of a microprocessor(s), that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation.

[0270] This definition of circuitry applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term circuitry also covers an implementation of merely a hardware circuit or processor (or multiple processors) or portion of a hardware circuit or processor and its (or their) accompanying software and/or firmware. The term circuitry also covers, for example and if applicable to the particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in server, a cellular network device, or other computing or network device.

[0271] The device 1300 may comprise a memory 1320. The memory 1320 may comprise random access memory and/or permanent memory. The memory 1320 may comprise at least one RAM chip. The memory 1320 may comprise solid-state, magnetic, optical and/or holographic memory, for example. The memory 1320 may be at least in part accessible to processor 1310. The memory 1320 may be at least in part comprised in processor 1310. The memory 1320 may be means for storing information. The memory 1320 may comprise computer instructions that processor 1310 is configured to execute. When computer instructions configured to cause the processor 1310 to perform certain actions are stored in the memory 1320, and the device 1300 overall is configured to run under the direction of the processor 1310 using computer instructions from the memory 1320, the processor 1310 and/or its at least one processing core may be considered to be configured to perform said certain actions. The memory 1320 may be at least in part comprised in the processor 1310. The memory 1320 may be at least in part external to the device 1300 but accessible to the device 1300.

[0272] The device 1300 may comprise a transmitter 1330. The device 1300 may comprise a receiver 1340. The transmitter 1330 and the receiver 1340 may be configured to transmit and receive, respectively, information in accordance with at least one standard.

[0273] The transmitter 1330 may comprise more than one transmitter. The receiver 1340 may comprise more than one receiver. The transmitter 1330 and/or the receiver 1340 may be configured to operate in accordance with Global System for Mobile Communication, GSM, Wideband Code Division Multiple Access, WCDMA, 5G/NR, SG-Advanced, i.e., NR Rel-18, 19 and beyond, Long Term Evolution, LTE, I5-95, Wireless Local Area Network, WLAN, Ethernet and/or Worldwide Interoperability for Microwave Access, WiMAX, standards, for example.

[0274] The device 1300 may comprise a Near-Field Communication, NFC, transceiver 1350.

[0275] The NFC transceiver 1350 may support at least one NFC technology, such as NFC, Bluetooth, Wibree or similar technologies.

[0276] The device 1300 may comprise a User Interface, UI, 1360. The UI 1360 may comprise at least one of a display, a keyboard, a touchscreen, a vibrator arranged to signal to a user by causing device 1300 to vibrate, a speaker and a microphone. A user may be able to operate the device 1300 via the UI 1360, for example to accept incoming telephone calls, to originate telephone calls or video calls, to browse the Internet, to manage digital files stored in memory 1320 or on a cloud accessible via the transmitter 1330 and the receiver 1340, or via NEC transceiver 1350, and/or to play games.

[0277] The device 1300 may comprise or be arranged to accept a user identity module 13130.

[0278] The user identity module 13130 may comprise, for example, a Subscriber Identity Module, SIN, card installable in device 1300. The user identity module 13130 may comprise information identifying a subscription of a user of device 1300. The user identity module 13130 may comprise cryptographic information usable to verify the identity of a user of device 1300 and/or to facilitate encryption of communicated information and billing of the user of the device 1300 for communication effected via device 1300.

[0279] The processor 1310 may be furnished with a transmitter arranged to output information from processor 1310, via electrical leads internal to the device 1300, to other devices comprised in the device 1300. Such a transmitter may comprise a serial bus transmitter arranged to, for example, output information via at least one electrical lead to the memory 1320 for storage therein. Alternatively to a serial bus, the transmitter may comprise a parallel bus transmitter.

[0280] Likewise, the processor 1310 may comprise a receiver arranged to receive information in the processor 1310, via electrical leads internal to the device 1300, from other devices comprised in the device 1300. Such a receiver may comprise a serial bus receiver arranged to, for example, receive information via at least one electrical lead from the receiver 1340 for processing in the processor 1310. Alternatively to a serial bus, the receiver may comprise a parallel bus receiver.

[0281] The device 1300 may comprise further devices not illustrated in Figure 13.

[0282] The processor 1310, memory 1320, transmitter 1330, receiver 1340, NEC transceiver 1350, UI 1360 and/or user identity module 13130 may be interconnected by electrical leads internal to the device 1300 in a multitude of different ways. For example, each of the aforementioned devices may be separately connected to a master bus internal to the device 1300, to allow for the devices to exchange information. However, as the skilled person will appreciate, this is only one example and depending on the embodiment various ways of interconnecting at least two of the aforementioned devices may be selected without departing from the scope of the present invention.

[0283] Figure 14 shows a non-transitory media 1400 according to some embodiments. The non-transitory media 1400 is a computer readable storage medium. It may be e.g. a CD, a DVD, a USB stick, a blue ray disk, etc. The non-transitory media 1400 stores computer program instructions, causing an apparatus to perform the method of any preceding process for example as disclosed in relation to the flow diagrams in this specification and related features thereof The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the preceding description, numerous specific details are provided, such as examples of lengths, widths, shapes, etc., to provide a thorough understanding of embodiments of the invention. One skilled in the relevant art will recognize, however, that the invention can be practiced without one or more of the specific details, or with other methods, components, materials, etc. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the invention.

[0284] While the forgoing examples are illustrative of the principles of the embodiments in one or more particular applications, it will be apparent to those of ordinary skill in the art that numerous modifications in form, usage and details of implementation can be made without the exercise of inventive faculty, and without departing from the principles and concepts of the invention. Accordingly, it is not intended that the invention be limited, except as by the claims set forth below.

[0285] The verbs "to comprise" and "to include" are used in this document as open limitations that neither exclude nor require the existence of also un-recited features. The features recited in dependant claims are mutually freely combinable unless otherwise explicitly stated. Furthermore, it is to be understood that the use of "a" or "an", that is, a singular form, throughout this document does not exclude a plurality.

Claims

1. Claims 1. A first apparatus, comprising: means for obtaining a selection, from a set, of a constellation having a non-zero mean, NZM, and supporting a superimposed pilot, SP; means for modulating a direct current, DC, component of the selected NZM constellation; and means for applying the modulated DC component to the selected NZM constellation to provide an adapted NZM constellation for signal modulation.

2. The first apparatus of claim 1, further comprising: means for extracting, prior to the modulating, the DC component of the selected NZM constellation.

3. The first apparatus of claim 1 or claim 2, further comprising: means for encoding, prior to the modulating, an input signal for signal modulation.

4. The first apparatus of claim 3, further comprising: means for mapping, subsequent to the modulating, the modulated input signal to a plurality of resource elements; and means for modulating the mapped modulated input signal using orthogonal frequency division multiplexing, OFDM, or discrete fourier transform-spread-frequency division multiplexing, DFT-S-FDM.

5. The first apparatus of any preceding claim, further comprising: means for reporting at least an indication of the selected NZM constellation to a second apparatus capable of receiving signals modulated using the signal modulation.

6. The first apparatus of any preceding claim, further comprising: means for reporting at least a capability of the first apparatus to modulate the DC component of the selected NZM constellation to a, or the, second apparatus capable of receiving signals modulated using the signal modulation.

7. The first apparatus of claim 5 or claim 6, further comprising: means for determining a configuration for the modulating of the DC component of the selected NZM constellation in response to at least one of: reporting of the indication of the selected NZM constellation; or reporting of the capability of the of the first apparatus.

8. The first apparatus of any preceding claim, wherein the selected constellation is a learned constellation of the first apparatus.

9. The first apparatus of any preceding claim, further comprising: means for performing signal modulation using the adapted NZM constellation.

10. The first apparatus of any preceding claim, wherein the first apparatus is a user device or a network device.

11. 11 A second apparatus, comprising: means for obtaining an indication of a selected non-zero mean, NZM, constellation; means for obtaining a modulated direct current, DC, component of the selected NZM constellation; and means for applying the modulated DC component to the selected NZM constellation to provide an adapted NZM constellation for signal demodulation.

12. The second apparatus of claim 11, wherein the NZM constellation supports a superimposed pilot at a first apparatus.

13. The second apparatus of claim 11 or claim 12, further comprising: means for extracting, prior to the modulating, the DC component of the selected NZM constellation.

14. The second apparatus of any of claims 11 to 13, further comprising: means for demodulating the received signal using orthogonal frequency division multiplexing, OFDM, or discrete Fourier transform-spread-frequency division multiplexing, DFT-S-FDM; and means for de-mapping the demodulated signal from a plurality of resource elements.

15. The second apparatus of claim 14, further comprising: means for decoding, subsequent to the demapping, the received signal.

16. The second apparatus of any of claims 11 to 15, wherein the indication is received in a report from a first apparatus;

17. The second apparatus of any of claims 11 to 16, further comprising: means for receiving at least a capability of a first apparatus to modulate the DC component of the selected NZM constellation.

18. The second apparatus of claim 16 or claim 17, further comprising: means for determining a configuration for the modulating of the DC component of the selected NZM constellation in response to at least one of: the received indication from the first apparatus; or the received capability over the first apparatus.

19. The second apparatus of any of claims 11 to 18, wherein the selected NZM constellation is a learned constellation of a first apparatus.

20. The second apparatus of any of claims 11 to 19, further comprising: means for receiving a signal from a first apparatus; and means for performing signal demodulation using the adapted NZM constellation.

21. The second apparatus of any of claims 11 to 20, wherein the second apparatus is a network device or a user device.

22. A method, comprising: obtaining a selection, from a set, of a constellation having a non-zero mean, NZM, and supporting a superimposed pilot, SP; obtaining a modulated direct current, DC, component of the selected NZM constellation; and applying the modulated DC component to the selected NZM constellation to provide an adapted NZM constellation for signal modulation.

23. A method, comprising: obtaining an indication of a selected non-zero-mean, NZM, constellation; obtaining a modulated direct current, DC, component of the selected NZM constellation; and applying the modulated DC component to the selected NZM constellation to provide an adapted NZM constellation for signal demodulation.

24. A non-transitory computer-readable medium having stored thereon computer-readable code, which, when executed by at least one processor, causes the at least one processor to perform a method, comprising: obtaining a selection, from a set, of a constellation having a non-zero mean, NZM, and supporting a superimposed pilot, SP; obtaining a modulated direct current, DC, component of the selected NZM constellation; and applying the modulated DC component to the selected NZM constellation to provide an adapted NZM constellation for signal modulation.

25. A non-transitory computer-readable medium having stored thereon computer-readable code, which, when executed by at least one processor, causes the at least one processor to perform a method, comprising: obtaining an indication of a selected non-zero-mean, NZM, constellation; obtaining a modulated direct current, DC, component of the selected NZM constellation; and applying the modulated DC component to the selected NZM constellation to provide an adapted NZM constellation for signal demodulation.