Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L27/00—Modulated-carrier systems
  • H04L27/26—Systems using multi-frequency codes
  • H04L27/2601—Multicarrier modulation systems
  • H04L27/2626—Arrangements specific to the transmitter only
  • H04L27/2627—Modulators
  • H04L27/2643—Modulators using symbol repetition, e.g. time domain realization of distributed FDMA
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L1/00—Arrangements for detecting or preventing errors in the information received
  • H04L1/08—Arrangements for detecting or preventing errors in the information received by repeating transmission, e.g. Verdan system
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L27/00—Modulated-carrier systems
  • H04L27/26—Systems using multi-frequency codes
  • H04L27/2601—Multicarrier modulation systems
  • H04L27/2626—Arrangements specific to the transmitter only
  • H04L27/2627—Modulators
  • H04L27/2634—Inverse fast Fourier transform [IFFT] or inverse discrete Fourier transform [IDFT] modulators in combination with other circuits for modulation
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L27/00—Modulated-carrier systems
  • H04L27/26—Systems using multi-frequency codes
  • H04L27/2601—Multicarrier modulation systems
  • H04L27/2647—Arrangements specific to the receiver only
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L27/00—Modulated-carrier systems
  • H04L27/26—Systems using multi-frequency codes
  • H04L27/2601—Multicarrier modulation systems
  • H04L27/2697—Multicarrier modulation systems in combination with other modulation techniques
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L27/00—Modulated-carrier systems
  • H04L27/32—Carrier systems characterised by combinations of two or more of the types covered by groups H04L27/02, H04L27/10, H04L27/18 or H04L27/26
  • H04L27/34—Amplitude- and phase-modulated carrier systems, e.g. quadrature-amplitude modulated carrier systems
  • H04L27/3405—Modifications of the signal space to increase the efficiency of transmission, e.g. reduction of the bit error rate, bandwidth, or average power

Definitions

• TITLE Method of telecommunication with binary coding with repeating symbols and corresponding devices
• the present invention relates to the field of telecommunications.
• the invention relates more particularly to digital communications with transmission of a radio signal (6G, 5G, WiFi, etc.) which uses multi-carrier modulation with constraints of robustness with respect to phase variations.
• a radio signal (6G, 5G, WiFi, etc.) which uses multi-carrier modulation with constraints of robustness with respect to phase variations.
• Digital communications refers to digital transmission chains that use well-known signal processing modules as shown in Figure 1.
• a classic chain is schematized by figure 1. This chain recovers Bit input data coming from a binary source such that the binary data are representative for example of an audio signal (voice), of a multimedia signal ( TV stream, Internet stream), etc.
• the input data is encoded by a COD error-correcting encoder (e.g. Turbo Code, LDPC, Polar code).
• An ENT interleaver interleaves the encoded data.
• a MAP symbol binary encoder converts a binary data packet, such as a codeword, to a point in a constellation (BPSK, QPSK, mQAM, etc.).
• This MAP encoder is also called a mapper and it is equivalently said that the mapper maps the input data to the points of the constellation.
• the output symbols of this mapper consist of the symbols of the constellation according to the mapping of the input data or equivalently we speak of the mapped data to denote the output symbols.
• the symbols are modulated by an N-subcarrier multi-carrier modulator MOD to generate multi-carrier symbols.
• the output of the modulator feeds a power amplifier in the transmitter to transmit a radio signal.
• mQAM Quadrature Amplitude Modulation according to the English terminology
• the symbol binary coder makes it possible to project, or also map, the binary data from the channel coder (error-correcting coder) on a two-axis plane following a given constellation.
• Each point in the constellation thus carries a packet made up of one or more bits.
• the number of bits that can be mapped on a given point of the constellation is as follows:
• OFDM modulation Orthogonal Frequency-division Multiplexing according to the English terminology
• DAB Downlink Control
• DVBT Downlink Control
• ADSL Advanced Driver Assistance Systems
• 4G 5G
• 5G 5G
• the intrinsic qualities of this OFDM modulation ensured its success in the aforementioned standards.
• these qualities we can cite that linked to a less spread spectrum than that of a single-carrier modulation, that linked to the resistance to time-dispersive channels and that linked to the reception which can be done with a simple equalization with a coefficient per carrier (i.e. ZF treatment for Zero Forcing according to the Anglo-Saxon terminology).
• FIG. 2 illustrates the output of a modulator implementing OFDM modulation.
• Such an OFDM modulator is often realized by means of an inverse Fourier transform (IFFT).
• IFFT inverse Fourier transform
• the different carriers of an OFDM symbol are modulated with the points of the constellation on which the data packets have been mapped.
• the frequency interval between carriers is 1/t s with t s the duration of an OFDM symbol.
• a guard interval of duration A is inserted between two successive symb OFDM symbols.
• This guard interval makes it possible to absorb the echoes caused by the multiple reflections during radio transmissions by the channel which is generally the air.
• This interval can be used to perform a first so-called coarse time synchronization of the system (between a transmitter and a receiver). It can thus allow reception to position the FFT window before demodulating the received radio signal.
• the implementation of the FFT on reception makes it possible to perform the inverse processing of the IFFT implemented on transmission, ie makes it possible to de
• FIGS. 3, 4 and 5 represent a mapping respectively on a QPSK, a 16QAM or a 64QAM respecting Gray coding.
• the Gray coding is such that between a point of the constellation and each of the nearest points, the packets of bits mapped on these two points are distinguished by only one bit. This particularity has the advantage of limiting the number of bits affected by a bad evaluation in reception of the received constellation point.
• Figures 4 and 5 illustrate the fact that the higher the order m of modulation, the more the system transmits binary information and can reach a high transmission rate and therefore improves the spectral efficiency of the system. However, the higher the modulation order, the less resistant the system is to disturbances related to the channel and to Additive White Gaussian Noise (AWGN).
• AWGN Additive White Gaussian Noise
• the choice of the modulation order must take into account the quality of the transmission link to hope to reach the maximum possible throughput.
• the Amplitude Modulation on two carriers in Quadrature can be referred to as a "Cartesian" mapping.
• This mapping is generally associated with Gray coding.
• the MAQ mapping is the most used. Indeed, it ensures a uniform Euclidean distance between the points of the constellation and it can be decoded in a simple way with threshold solutions.
• a QAM mapping thus makes it possible to guarantee high throughputs.
• a QAM mapping is for example retained in the DVB-T, IEEE 802.11 (WiFi), 3GPP 4G (release and following) standards and recently in the 3GPP 5G standard (release 15 and following).
• the error-correcting coder COD also called channel coder, implements a code generally based on a “mother” code or base code to which a base efficiency corresponds.
• the base code is 1/2 for a duo-binary turbo code, it is more often 1/3 or even 1/5 for the new LDPC codes of the 3GPP 5G standard.
• Figure 6 illustrates a 1/3 efficiency turbocoder.
• the turbocoder comprises a first encoder Encod I, a second encoder Encod II and an interleaver n.
• the output data includes a systematic part made up of the input data x i and a redundancy part y i .
• the redundancy part comprises the coded data and the coded data y 2 .
• the coded data y1 comes from the coding by the first encoder Encod I of the input data x i .
• the coded data y 2 comes from the coding by the second encoder Encod II of the interlaced input data x i .
• the data resulting from the channel coding are then punctured to adapt to the desired coding rate (2/3, 3/4, etc.).
• Coding makes it possible to introduce redundancy into the binary data to combat the disturbances generally introduced by the transmission channel and which result in erasures or errors due in particular to fading phenomena.
• one means is to reduce the coding efficiency (number of useful bits/total number of bits).
• the 5G standard has thus provided for coding yields of the order of (1/5, 1/10 and 1/20) to address the new services called "very robust" URLLC (Ultra-Reliable Low-Latency Communication) which must respond in particular to the requirements of telemedicine.
• URLLC Ultra-Reliable Low-Latency Communication
• the repetition of the coded data is a simple solution which provides satisfactory results in terms of the robustness of the system for a so-called Gaussian channel.
• the subject of the invention is a telecommunication method comprising rl rate coding by a binary coder, data mapping by a mapper on points of a constellation to obtain symbols, multi-carrier modulation by an N-sub modulator -carriers with symbol mapping on the N sub-carriers and multi-carrier symbol transmission.
• the method includes: symbol repetition before mapping onto the N modulator subcarriers.
• the repetition of the symbols from the mapper makes it possible to increase the robustness of the transmission with respect to fading introduced by the propagation channel and with respect to phase noise.
• the process does not modify the energy of the multi-carrier signal nor its spectrum while keeping a very reduced complexity.
• the invention further relates to a reception method comprising: demodulation of a multi-carrier symbol received to estimate N symbols, averaging of the repetitions of the same symbol to estimate a symbol of a constellation, demapping of the symbols to estimate data mapped to these constellation symbols, decoding the data.
• the invention further relates to telecommunications equipment which comprises: a demodulator with N sub-carriers for demodulating a multi-carrier symbol received and estimating N symbols, a de-repeater for averaging repetitions of the same symbol and estimating a symbol of a constellation, a demapper for demapping L constellation symbols and estimating data mapped on these constellation symbols, a decoder for decoding the data.
• the invention further relates to a digital signal transmitted or received comprising a multi-carrier symbol constructed from symbols of a polar constellation, at least one of the symbols of which has been repeated before multi-carrier modulation to form a repetition pattern, a polar constellation comprising a set of M points whose coordinates expressed in polar form , called polar coordinates by reference to a representation with two axes delimiting four quadrants, are determined such that real number positive being the step in amplitude of the constellation.
• the same number of repetitions is applied to all the symbols before mapping.
• At least one symbol is not repeated or its number of repetitions is different from the number of repetitions of another symbol.
• the number of repetitions is determined to obtain a yield r2 lower than r1.
• the method further comprises an interleaving after repetition, of the N symbols mapped onto the N sub-carriers.
• the constellation comprises a set of M points whose coordinates expressed in polar form called coordinates polar with reference to a two-axis representation, are determined such that real number being the step in amplitude of the constellation.
• a polar constellation according to the invention comprises a set of M points whose coordinates are expressed in polar form
• a phase shift on one or more of the points mapped on the carriers may occur during transmission, for example due to a Doppler effect linked to a movement of the transmitter and/or receiver, or due to imperfections in the oscillators.
• the receiver can advantageously determine without ambiguity the received points of the constellation.
• the polar constellation makes it possible to absorb up to a certain phase shift value determined by the number of points of the constellation on the same circle.
• the polar constellation used also makes it possible to increase the resilience of the system with respect to phase variations caused by the imperfections of the oscillators, in particular for high frequencies beyond 6 GHz.
• the pitch is a parameter.
• the telecommunication method according to the invention makes it possible to address various constraints with respect to variations in amplitude (noise) by modifying the value of the step which is configurable. This method is therefore very flexible and adaptable as a function of the noise constraints.
• the two axes delimit quadrants and the polar coordinates are determined by quadrant:
• This mode makes it possible to use large modulation orders to meet the increasing demand for bit rate even in the absence of pilots while making it possible to absorb a phase variation that can go up to ⁇ /2 by limiting the number to four points on the same circle.
• the polar constellation according to this mode is defined by quadrant and replicated between the different quadrants with the particularity that the phase of the points is the same within a quadrant.
• This mode makes it possible to use average modulation orders to meet the increasing demand for bit rate even in the absence of pilots while making it possible to absorb a phase variation that can go up to ⁇ /2 by limiting the number of points on the same circle of four.
• This embodiment is particularly advantageous because the symbols obtained can be demodulated by a conventional demodulator, they are compatible with demodulators adapted to conventional 16-QAM modulation according to which the four points of a quadrant are distributed according to a square.
• the two axes delimit quadrants and the polar coordinates are determined per set of two quadrants
• This mode makes it possible to use large modulation orders to meet the increasing demand for bit rate even in the absence of pilots while making it possible to absorb a phase variation that can go up to ⁇ by limiting the number of points on a same circle for two.
• the two axes delimit quadrants and for two quadrants taken . . whole
• the polar constellation according to this mode is defined by block of two quadrants and replicated between these two blocks with the particularity that the phase of the points is the same within a block.
• the polar coordinates are further determined such that with a non-zero real.
• This mode uses so-called spiral constellations defined on all the quadrants ie 2n, that is to say that the four quadrants are considered as a whole.
• This embodiment of the method makes it possible to introduce a phase variation which can go up to 2n on any point of the constellation.
• the receiver can unambiguously determine the constellation points received since the constellation makes it possible to absorb any phase rotation up to 2n.
• Such a mode is particularly suitable for systems confronted with a lot of phase noise, which is the case when the communications take place in the TeraHz band. Indeed, the oscillators exhibit a lot of phase noise at these frequencies.
• Spiral constellations make it possible to obtain both good immunity to noise and good immunity to phase variations and are therefore particularly advantageous for communications in the TeraHz range.
• This mode has as good a robustness to phase variations as a mode in which all the points of the constellation have the same phase, but in addition it advantageously increases the minimum Euclidean distance of the points of the constellation.
• the polar coordinates are further determined such that
• the polar constellation according to this mode includes points all having the same phase with a constant amplitude step between two neighboring steps.
• This type of polar constellation has a high immunity to phase variations i.e. up to 2n but a relatively low immunity to noise.
• the modulation is implemented by an inverse Fourier transform.
• the inverse Fourier transform makes it possible to efficiently and simply perform the transformation from a frequency domain to a time domain and to obtain an OFDM symbol.
• the method further comprises: an estimation per constellation symbol of a phase error by comparing projections on axes in quadrature of the symbol with the points of the constellation, a correction of the constellation symbols of a common phase error after averaging the estimated phase errors.
• FIG 1 is a diagram illustrating a transmission baseband processing chain according to the prior art
• Figure 2 is a classic time-frequency representation of OFDM symbols
• Figure 3 is a representation of a classic QPSK constellation
• Figure 4 is a representation of a typical 16QAM constellation
• Figure 5 is a representation of a typical 64QAM constellation
• Figure 6 is a schematic of a 1/3 efficiency turbocoder
• Figure 7 is a representation of a polar spiral constellation
• FIG 8 Figure 8 is an illustration of the result of a frequency deviation between transmitter and receiver with the spiral constellation of Figure 7
• Figure 9 is a representation of a polar constellation defined by quadrant of ⁇ /2
• Figure 10 represents the maximum of the phase variation due for example to a Doppler effect that the constellation of figure 9,
• FIG 11 is a simplified diagram of a baseband transmission chain according to one embodiment of the invention.
• FIG 12 is a simplified diagram of a baseband reception chain according to one embodiment of the invention.
• FIG 13 is a diagram of one embodiment of the processing performed on the repetitions by the DREP module
• FIG 14 is a diagram for an FDD mode of the correction performed by a module ⁇ of the receiver of a user UE1,
• Figure 15 is a diagram for an FDD mode of the correction performed by a ⁇ module of a base station which receives several users,
• FIG 16 is a simplified diagram of a baseband receive chain for a TDD mode with phase correction performed in the time domain according to one embodiment of the invention
• Figure 17 is a diagram of the simplified structure of an embodiment of equipment according to the invention capable of implementing a telecommunication method according to the invention
• FIG 18 is a diagram of the simplified structure of an embodiment of equipment according to the invention capable of implementing a reception method according to the invention
• Figure 19 shows curves which illustrate the performance obtained in terms of bit error rate (BER) as a function of the signal to Gaussian additive white noise ratio (SNR) obtained with a conventional technique in the case of a 16QAM constellation,
• BER bit error rate
• SNR signal to Gaussian additive white noise ratio
• Figure 20 presents curves which illustrate the performance obtained in terms of bit error rate (BER) as a function of the Gaussian additive signal-to-white noise ratio (SNR) obtained with a method according to the invention in the case of a 16QAM constellation,
• BER bit error rate
• SNR Gaussian additive signal-to-white noise ratio
• FIG 21 presents curves which illustrate the performance obtained in terms of bit error rate (BER) as a function of the Gaussian additive signal-to-white noise ratio (SNR) obtained with a method according to the invention in the case of a 16-point polar constellation
• Figure 22 presents curves which give the minimum SNR level as a function of the Doppler to obtain a bit error rate of less than 5.10 -5 at the output of the system obtained with a method according to the invention for lines formed of squares and obtained with a conventional method for curves formed of crosses.
• BER bit error rate
• SNR Gaussian additive signal-to-white noise ratio
• the general principle of the invention is based on the repetition of symbols resulting from a binary symbol coding and before their modulation by a multi-carrier modulator.
• the symbols correspond to points of the constellation used on transmission.
• the invention thus makes it possible to introduce redundancy closer to the modulation than does a channel coder and to fight more effectively against disturbances (fading) introduced by the channel or against the phase noise.
• All symbols from the mapper can be repeated in the same number or in different numbers between symbols. When at least one number of repetition(s) is different from the others, the method may consist in repeating all the symbols by the same number R then in deleting the excess copies of symbols to reach the respective number or numbers of repetition( s).
• the deletion can then be likened to punching the symbols to reach the number of repetition(s) defined by symbol coming from the mapper.
• the number of repetition(s) and the possible deletion of repetition(s) conform to a word pattern which determines a yield.
• a yield can correspond to several reasons.
• a pattern corresponds to a single yield.
• the following example is based on a QAM constellation.
• the values ai and bi of each constellation point at the output of the mapper depend on the binary data di of the stream at the input of the mapper.
• the binary stream typically comprises data having been coded upstream in the transmission chain by a channel coder.
• a return q/2 can be obtained with the pattern: QO, QO, Ql, Ql, Q2, Q2, Q3, Q3 a return q/3 can be obtained with the pattern: QO, QO, QO, QO, Ql, Ql, Q2, Q2, Q2, Q3, Q3, Q3 a q/4 yield can be obtained with the pattern: QO, QO, QO, QO, Ql, Ql, Ql, Q2, Q2, Q2, Q2 , Q3, Q3, Q3 a 2q/5 return can be obtained with the pattern: QO, QO, QO, Ql, Ql, Q2, Q2, Q2, Q3, Q3
• the repetition(s) of the same output symbol of the mapper can be contiguous as shown above or non-contiguous.
• An interlacing can be performed on the succession of symbols with contiguous repetition(s) to obtain a sequence of symbols in which at least one repetition or even all the repetitions are not contiguous. This interleaving can occur simultaneously with the mapping of the symbols onto the subcarriers.
• the constellation is a polar constellation.
• a polar constellation is defined by M points distributed on concentric circles with a constant pitch p between the circles.
• the polar constellation relies on a polar and non-Cartesian basis to be invariant to phase variations.
• the step p is a non-zero positive real number.
• the points of the constellation are therefore distributed over at least two distinct circles.
• the M points have coordinates expressed in polar form say polar coordinates by reference to a representation with two axes delimiting four quadrants of size ⁇ /2 , with the constraint that is the amplitude of a point, ⁇ m is the phase of this point.
• M is the order of the modulation.
• the constellation has the particularity that there is at most one point on each circle per quadrant considered for the expression in polar form of the constellation.
• the constellation is determined on a quadrant of size 2n, i.e. the quadrant then there is at most one point per circle.
• the constellation is determined by quadrant of size it , i.e. for the quadrants then there is at most one point per semi-circle.
• the constellation is determined by quadrant of size n/2, i.e. for the quadrants then there is at most one point per quarter circle.
• FIG. 7 represents a first configuration of a polar constellation used according to the invention, called a spiral.
• This first configuration has the particularity that the points are distributed over a quadrant which represents [0 — 2 ⁇ [.
• Each point has the coordinates: and a phase ⁇ m with a determined phase difference between two successive points ie on two successive circles, for example a constant difference of successive points of the spiral constellation thus have a constant deviation both in amplitude and in phase. Therefore, unlike configurations not illustrated, the phase ⁇ m is not constant but varies between successive points.
• This first configuration is particularly advantageous with respect to phase variations because the demodulation in reception can be performed on only an amplitude detection of the constellation points received.
• FIG. 8 illustrates the result of a frequency difference between the transmitter and the receiver with the constellation defined above over several consecutive OFDM symbols.
• FIG. 8 illustrates an example of the phase variation that can impact the points of the so-called spiral modulation, illustrated by FIG. 7, which remains acceptable for obtaining correct demodulation.
• This "spiral" structure makes it possible to resist strong phase variations between the transmitter and the receiver of the system.
• This embodiment is particularly suitable for systems operating in TeraHertz for which there is a very significant phase noise due to inefficient oscillators.
• FIG. 9 represents a second configuration of a polar constellation used according to the invention.
• Each point of a quadrant has the coordinates: . Thereby, for each quadrant, there is only one point per concentric circle and the phase ⁇ m of the point m is chosen according to a given criterion, for example with a constant pitch of ⁇ /8 between two points or a pitch of zero between the two points on the furthest circles in the same quadrant.
• This second mode is robust against additive Gaussian white noise because the minimum distance between the emitted points is large.
• the phase ⁇ m is a multiple of ⁇ /12 and more particularly.
• This second embodiment as illustrated is very advantageous because it is compatible with many existing OFDM demodulators capable of demodulating an OFDM/16QAM modulation. Indeed, for each quadrant, the points are close to those of a classic 16QAM constellation as represented in figure 4.
• FIG. 10 represents the maximum of the phase variation due for example to a Doppler effect which can impact the points of the modulation, illustrated by FIG. 9, during transmission, which remains compatible with obtaining correct demodulation in reception.
• the receiver can demodulate the modulation points received despite the phase variation between the transmitter and the receiver and this without ambiguity.
• This second configuration of a polar constellation makes it possible to optimize the robustness with respect to additive white Gaussian noise with a robustness linked to less phase variations than for the first configuration.
• FIG. 11 is a simplified diagram of a baseband transmission chain representing the essential steps of a method 10 according to the invention.
• the COD encoder performs an 11 coding of channel according to known techniques.
• the string may include an interleaver to interleave the encoded data.
• the binary stream at the input of the mapper is mapped 12 according to known techniques on the points of a constellation.
• the repetition 13 intervenes between the binary symbol coder also called mapper MAP and the modulator MOD which generates 14 multi-carrier symbols X 0fdm .
• the OFDM-type modulator MOD conventionally implements an FFT of size N corresponding to the number of sub-carriers.
• FIG. 12 is a simplified diagram of a baseband reception chain representing the essential steps of a reception method according to the invention.
• the received multi-carrier symbols Xr Ofdm are demodulated 21 by a DEMOD demodulator which performs the inverse operation of the modulator on transmission.
• An OFDM type demodulator conventionally implements an IFFT of size N corresponding to the number of sub-carriers.
• the symbols are conventionally equalized 22, that is to say they are weighted with the coefficients of the transmission channel H which separates the transmitter from the receiver. Knowing the repetition pattern used on transmission, a symbol and its repetitions are added together and normalized 23 by the DREP module before being transmitted to the DEMAP demapper which performs 24 the inverse function of the MAP mapper.
• Figure 13 is a diagram of an example of the use of repetitions performed by the DREP module.
• This DREP module knows the repetition pattern used on transmission.
• the example relates to a repetition with a yield q/4 which corresponds for example to the example given previously of a repetition on transmission with the pattern: QO, QO, QO, QO, QO, Ql, Ql, Ql, Q1, Q2, Q2, Q2, Q2, Q3, Q3, Q3, Q3.
• the OFDM type receiver can demodulate the data of the constellation by determining only the amplitude (ar(i)) of the point received for a quadrant.
• the quadrant is worth 2n, there is only one point on a circle.
• the Acp module can determine the point whose the amplitude is the closest, this point is the one emitted at the origin, noted for example La phase of the point of origin is therefore known, it is ⁇ (1) .
• phase error estimate on the received point Qr(1) is then given by: with b ⁇ (1) noise on the estimate.
• the operations described above for the spiral constellation are carried out for a quadrant of ⁇ /4 after having identified the quadrant to which the received point belongs.
• phase error estimate can be repeated by the ⁇ module for each of the points from the DREP module:
• the number N p can be equal to the number of points at the output of the DREP module in the case of a transmission in TDD (Time Division Duplex) mode.
• TDD Time Division Duplex
• a multi-carrier symbol Xr Ofdm is intended for a single user, ie a single receiver.
• the receiver is moving, there is only one Doppler effect which affects the multi-carrier symbol Xr Ofdm and therefore all the points at the output of the DREP module.
• the number N p can correspond to a subset of the subcarriers reserved for the downlink or uplink direction in FDD (Frequency Division Duplex) mode.
• N p is deduced from a multiple of 12 sub-carriers since each user served by the same base station benefits from a multiple of 12 sub-carriers.
• the N p points of a multi-carrier symbol Xr Ofdm can then be corrected by the estimation of the common phase error. This correction can be done in the frequency domain by the module ⁇ as represented in figure 12.
• FIG. 14 is a diagram for an FDD mode of the correction carried out by a module ⁇ of a user UE1 for which N q sub-carriers among the N sub-carriers of a multi-carrier symbol X O fdm transmitted by a station of base.
• N pl points to consider for the phase error estimation and for the calculation of the average to obtain the common phase error
• Each point is weighted with the phase error common to obtain a corrected point
• Each user UEj is assigned N q j subcarriers among the N subcarriers.
• N p j points to consider per user UEj for the phase error estimation and for the calculation of the average to obtain the common phase error
• each point among the points which are intended for him is weighted by common phase error to obtain a corrected point
• each point among the points which are intended for it is weighted by the phase error common to obtain a corrected point
• each point among the points assigned to it is weighted by the common phase error p
• the common phase error p To obtain a point corrected
• the common phase error correction can be done in the frequency domain as for the FDD mode but also in the time domain by the multiplier ® as represented in the figure 16.
• This temporal correction requires a reception chain with two branches, a first branch which makes it possible to determine the common phase error by implementing the steps 21, 22, 23 and 25 already described with regard to FIG. second branch which comprises the multiplier ®, another demodulator DEMO identical to that of the first branch, the demapper DEM AP and the decoder DECOD.
• This other demodulator implements a demodulation 21 whose output feeds the demapper which performs the demapping 24.
• the output of the demapper can feed a decoder DECOD which implements the decoding 26.
• FIG. 17 The simplified structure of an embodiment of equipment according to the invention capable of implementing a telecommunication method according to the invention is illustrated by FIG. 17.
• This equipment DEV_E can just as well be a base station as a mobile device.
• the DEV_E equipment comprises a transmitter (not shown), a microprocessor pP whose operation is controlled by the execution of a program Pg whose instructions allow the implementation of a telecommunication method 10 according to the invention.
• Equipment DEV_E further comprises an encoder COD, a mapper MAP, a repeater REP, a modulator MOD, a memory Mem comprising a buffer memory.
• An OFDM-type modulator MOD is conventionally produced by implementing an inverse Fourier transform IFFT.
• the code instructions of the program Pg are for example loaded into the buffer memory Mem before being executed by the processor pP.
• the pP microprocessor controls the various components: COD encoder, MAP mapper, REP repeater, MOD modulator, transmitter.
• the configuration of the equipment includes at least the type of modulation and its order, the word pattern of the repetitions or the rate and a possible interleaving parameter and/or a possible puncturing parameter.
• the order of the modulation determines the number of constellation points.
• the parameter setting of the equipment further includes at least the constellation step as well as the value of a ⁇ .
• the microprocessor pP controls: the coding of the input Bits, the mapping of the coded data on the points of the constellation to generate symbols, the repetition of the symbols according to the word pattern and the mapping of the symbols repeated on the N sub-carriers of the modulator to obtain after modulation of the multi-carrier symbols, transmitting by the transmitter the radio signal representative of the multi-carrier symbols.
• the microprocessor pP determines the polar coordinates of the points of the constellation: as
• FIG. 18 The simplified structure of an embodiment of equipment according to the invention capable of implementing a reception method according to the invention is illustrated by FIG. 18.
• This equipment DEV_R can just as well be a base station as a mobile device.
• the DEV_R equipment includes a receiver (not shown), a microprocessor pP whose operation is controlled by the execution of a program Pg whose instructions allow the implementation of a reception method 20 according to the invention.
• Equipment DEV_R further comprises a demodulator DEMOD, an equalizer EGA, a de-repeater DREP, a demapper DEMAP, a decoder DECOD, a memory Mem comprising a buffer memory.
• the DEMOD demodulator is of the OFDM type, it conventionally implements a Fourier transform FFT.
• the DEV_R equipment can also include a phase error corrector ⁇ ..
• the code instructions of the program Pg are for example loaded into the buffer memory Mem before being executed by the processor pP.
• the pP microprocessor controls the various components: DEMAP demapper, DEMOD demodulator, receiver.
• the receiver receives a radio signal representative of multi-carrier symbols.
• the demodulator DEMOD performs the reverse operation of the MOD modulator.
• the DEMAP demapper performs the reverse operation of the MAP mapper.
• the parameterization of the equipment comprises at least the type of modulation and its order, the word pattern of the repetitions or the rate and a possible interleaving parameter and a possible puncturing parameter.
• the parameter setting of the equipment further comprises at least the pitch p of the constellation as well as the value of ⁇ 1 .
• the microprocessor pP controls the different components to: receive the radio signal representative of the multi-carrier symbols, that the DEMOD demodulator demodulates the multi-carrier symbols to estimate the symbols mapped on the different carriers, that the equalizer EGA weights the symbols of the coefficients of the transmission channel, that the de-repeater DREP averages the repetitions of the same symbol knowing the repetition pattern (or knowing the rate and a possible interleaving parameter and a possible puncturing parameter), that the demapper DEMAP demaps constellation symbols to estimate Bit data.
• the microprocessor pP determines the polar coordinates of the points of the constellation: as controls the phase error corrector ⁇ to estimate the phase error to calculate the average and obtain the common phase error A ⁇ p and to correct the symbols of the constellation before demapping.
• the invention also applies to one or more computer programs, in particular a computer program on or in an information medium, adapted to implement the invention.
• This program may use any programming language, and be in the form of source code, object code, or intermediate code between source code and object code such as in partially compiled form, or in any other form desirable for implementing a method according to the invention.
• the information carrier can be any entity or device capable of storing the program.
• the medium may comprise a storage means, such as a ROM, for example a CD ROM or a microelectronic circuit ROM, or else a magnetic recording means, for example a USB key or a hard disk.
• the information medium can be a transmissible medium such as an electrical or optical signal, which can be conveyed via an electrical or optical cable, by radio or by other means.
• the program according to the invention can in particular be downloaded onto a network of the type Internet.
• the information carrier may be an integrated circuit in which the program is incorporated, the circuit being adapted to execute or to be used in the execution of the method in question.
• the curves in FIGS. 19, 20 and 21 illustrate the performance obtained in terms of bit error rate (BER) as a function of the signal to Gaussian additive white noise ratio (SNR) for code rates of 1/2 which is the code mother of a duo-binary turbo code (1504 bits), of 1/4 and of 1/8.
• BER bit error rate
• SNR signal to Gaussian additive white noise ratio
• the curves in FIG. 22 give the minimum SNR level as a function of the Doppler to obtain a bit error rate of less than 5.10 ⁇ 5 at the output of the system.
• the lines formed by the squares are obtained with a method according to the invention in the case of a polar constellation with 16 points (order 16) for yields of 1/4 and 1/8.
• the curves formed by crosses are obtained with a conventional process and a polar constellation for yields of 1/2, 1/4 and 1/8.

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• Engineering & Computer Science (AREA)
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• Signal Processing (AREA)
• Physics & Mathematics (AREA)
• Discrete Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Mathematical Physics (AREA)
• Digital Transmission Methods That Use Modulated Carrier Waves (AREA)

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• 2020
  • 2020-11-10 FR FR2011554A patent/FR3116169A1/fr not_active Withdrawn
• 2021
  • 2021-11-09 EP EP21820297.6A patent/EP4244992A1/de active Pending
  • 2021-11-09 US US18/252,256 patent/US20230412441A1/en active Pending
  • 2021-11-09 WO PCT/FR2021/051982 patent/WO2022101577A1/fr unknown

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