EP3058675A1

EP3058675A1 - Method of reception and receiver for single-carrier cyclic waveform coded serial digital transmision

Info

Publication number: EP3058675A1
Application number: EP14796821.8A
Authority: EP
Inventors: Benjamin Ros
Original assignee: Centre National dEtudes Spatiales CNES
Current assignee: Centre National dEtudes Spatiales CNES
Priority date: 2013-10-18
Filing date: 2014-10-15
Publication date: 2016-08-24
Also published as: FR3012276A1; US20160234052A1; WO2015055952A1; US9654325B2

Abstract

The invention relates to a method of receiving digital data transmitted on a coded serial digital transmission modulated on a noisy channel with non-stationary equalisation attenuation. Digital data are stored (33) associating a value of quality of transmission with the information elements received, and a mutual information value Ik is computed (34) for each value of said quality of transmission. Said value of quality of transmission consists of an equivalent signal/noise plus interference ratio calculated as a function of said method of equalisation on the basis of various signal/channel noise ratio values measured for the various temporal symbols of information elements received of the signal received corresponding to one and the same information element and according to interference due to said waveform.

Description

RECEIVING METHOD AND RECEIVER FOR DIGITAL TRANSMISSION OF CYCLIC WAVE-FORM CODED CODED TRANSMISSION

UNIQUE

The invention relates to a reception method and a receiver for coded and modulated serial digital transmission over a non-stationary attenuation attenuated channel having a waveform selected from the group of cyclic waveforms comprising cyclically repeated, and said to single carrier, that is to say having fluctuations corresponding to those of a single carrier. These may include SC-OFDM (Single-carrier Orthogonal Frequency Division Multiplexing) waveforms, EW-SC-OFDM (Single-carrier Orthogonal Frequency Division Multiplexing, and Expansion and Weighting), SC-FDMA (Single-carrier Frequency Division Multiple Access), WCP-OFDM (Single-Carrier Orthogonal Frequency Division Multiplexing with Weighted Cyclic Prefix), Cyclic TDM (Cyclic Time Division Multiplexing) ...

In particular, the known waveforms SC-OFDM or EW-SC-OFDM implementing an orthogonal frequency distribution in the form of multiple sub-carriers but having a single carrier transmission scheme, can for example be used for the link the amount of wireless high-speed data transmissions from mobile terminals (eg, LTE, fourth-generation standard for high-speed wireless data transmissions between mobile phones and / or data terminals), or for the link descendant of DVD-NGH

(see http://www.dvb.org/resources/public/standards/A160J3VB- for the satellite link) Such waveforms have the following advantages:

with respect to an OFDM waveform (orthogonal frequency division multiplexing):

^■ less sensitivity to synchronization errors (but greater than that of a linear convolution waveform),

^■ reduced crest factor (PAPR); - compared to a linear convolution: simpler equalization.

The estimation of the performance of the physical layer of such a transmission is important to allow the planning of the network dimensioning, for the optimization of the transmission parameters (interleaving, coding, guard intervals, number of subcarriers. .) on very high spatial correlation channels, requiring the terminal to travel long distances.

A coded and modulated serial digital transmission over a non-stationary attenuation channel noise is established between:

an emitter comprising:

^■ an encoding device adapted to generate, from a bit stream to be transmitted, said transmitted stream of bits, at least one stream of codewords, said flux emitted codeword resulting from coding according to at least one method predetermined coding, of said transmitted bit stream,

^■ a modulation device adapted to generate at least one modulated element stream, said flux emitted from modulated elements according to a predetermined modulation scheme, each flux emitted from modulated elements being representative of at least a portion of each stream issued coded words,

^■ a transmitting device, on a noisy channel in nonstationary attenuation of a signal, said transmitted signal, incorporating a flow of transmitted symbols representative of each flux emitted from modulated elements,

- and a receiver comprising:

^■ a receiving device adapted to receive a signal, said received signal, is received by a receiving device, said received signal incorporating a received symbol streams corresponding to a flux emitted component modulated on said channel, the received signal having a a waveform selected from the group of cyclic waveforms comprising cyclically repeated and single-carrier guard intervals having fluctuations corresponding to those of a single carrier, each modulated element being represented by a plurality of received symbols,

^■ a demodulation device adapted to generate at least one coded word stream, said received stream of coded words, from each received stream of modulated elements,

^■ at least one decoding device adapted to generate a bit stream, said received stream of bits, for decoding each received stream of codewords according to a decoding method corresponding to a coding method implemented by the transmitter.

The coding of such a digital transmission enhances its reliability. In various applications, the transmission channel used, generally of wireless type (radio frequencies and / or microwaves ...) has a non-stationary attenuation, that is to say which varies substantially in time during the transmission. of each code word. This phenomenon is reinforced by the presence of at least one interleaver.

This is the case, for example, with mobile receiver terminals (for example of the GPRS or UMTS type, Satellite DVB-SH) and / or when the coding is of the "turbocode", LDPC or iterative type. Indeed, the channel conditions and its performance can be fluctuating depending on the position of the receiver. In addition, when an interleaver is provided, the function of such an interleaver has the effect of reducing variations in attenuation seen by code word.

Nevertheless, in general numerical data representative of variations over time of attenuation and noise of the channel are available. These digital data can come from the known characteristics of the interleaver, or from known statistical characteristics from the physical properties of a channel. The channel data is estimated from the received signal on either pilot elements or modulated elements. The successive signal-to-noise ratios by codeword are reconstituted from the interleaver.

In this general context, a problem that arises is the prediction of the performance of the transmission, that is to say the determination, without performing the decoding, of an error rate ER (error rate BER bit and / or PER word error rate) in the bit stream received as a function of attenuation variations of the channel during the reception of each coded word. Such a performance prediction must make it possible in particular to optimize the design of said constituent elements, and in particular to choose appropriate protocols to ensure good transmission quality: automatic retransmission request (ARQ technique) possibly hybrid (H-ARQ); incremental redundancy (IR); combination of Chase; adaptation of the characteristics of the transmitter and / or the transmission link: choice of the coding method, signal strength, modulation scheme, etc. Such a prediction of performance can also make it possible to avoid oversizing the receivers and their antennas.

FR 2 952 254 describes a reception method and a receiver in which:

digital data are memorized making it possible to determine:

^■ at least one value, said transmission quality Q ^ of formula

Ck .E No, where Ck represents each attenuation value of the channel over time, where k is a time index, E _s represents an average energy per emitted modulated element and No represents a spectral density of a Gaussian white noise on the channel,

^■ and the variations over time of said transmission quality Q ^ pom each element received from the received stream of modulated elements,

in a first step, a mutual information value I _k is elaborated for each value of said transmission quality Q _k , according to a predetermined function of said transmission quality Q _k ,

in a second step, an average of mutual information is elaborated for each coded word of the received stream of coded words, by averaging the different mutual information values I _k elaborated in the first step for the different values taken by said Q _k transmission quality on said coded word,

in a third step, at least one value of the error rate ER of the received stream of bits is produced without performing the decoding for each coded word of the received stream of codewords, from each value of the average of mutual information. developed in the second step, and using data stored memories representative of variations of an equivalent error rate according to at least one function, called standard function, of the signal-to-noise ratio, each standard function being predetermined for the coding and decoding devices on an additive Gaussian white noise channel.

This method and this receiver are entirely satisfactory, and make it possible in particular to obtain a performance prediction without performing decoding, both by taking into account the true attenuation variations of the channel, and with a good accuracy of the results. high reliability and light and fast computer processing, and therefore an optimization of the quality of the transmission. They are applicable in particular to waveform transmissions of OFDM or FDMA type. However, this performance prediction is in no way applicable to single-carrier cyclic waveforms for which interference exists between modulated elements by construction, a coded word not necessarily comprising an integer of modulated elements, preventing a priori any evaluation of the quality of transmission Q _k .

In this context, the aim of the invention is to propose a method and a receiver incorporating a prediction of the performance of the transmission without performing the decoding, as a function of attenuation variations of the channel during the reception of each coded word, applicable to the forms. single-carrier cyclic waveforms, including SC-OFDM, EW-SC-OFDM, SC-FDMA, cyclic WCP-OFDM TDM, which provides good accuracy of results, high reliability and light computing fast, and therefore an optimization of the quality of the transmission. In particular, the invention aims at providing a reception method and a receiver incorporating a performance prediction applicable to these waveforms and which has the same qualities as the performance prediction described in FR 2 952 254.

The invention also aims at providing such a method and such a receiver allowing a performance prediction using only the known parameters of the receiver waveform and respecting the structure of the real receiver which performs the equalization in the frequency domain before application of a fast inverse Fourier transform. The invention also aims at providing such a method and such a receiver that allow a fast performance prediction, and in particular without requiring the use of an additional Fourier transform operation dedicated solely to this prediction.

To this end, the invention relates to a method for receiving digital data transmitted over a coded and modulated serial digital transmission over a non-stationary attenuation attenuated channel, in which:

a signal, said received signal, is received by a reception device, said received signal incorporating a stream of temporal symbols of information elements corresponding to a stream of temporal symbols of information elements transmitted on said channel and representative of information elements corresponding to the data to be transmitted, each information element being represented by a plurality of said time symbols, the received signal having a waveform chosen from the group of cyclic waveforms comprising cyclically repeated and single-carrier guard intervals with fluctuations corresponding to those of a single carrier,

a predetermined equalization method is applied by said reception device to the time symbols of received information elements,

at least one stream of coded words, said received stream of coded words, is generated by demodulation from the stream of temporal symbols of received information elements,

a stream of bits, called bits received stream, is generated by decoding each received stream of codewords, according to a decoding method corresponding to a coding method implemented on transmission on the channel of the transmitted symbol stream,

process in which

digital data is stored associating a value of transmission quality with the information elements received,

in a first step, a mutual information value Ik is produced for each value of said transmission quality according to a predetermined function of said transmission quality, characterized in that said transmission quality value comprises a signal-to-noise ratio plus equivalent interference calculated as a function of said equalization method from different values of signal-to-noise ratio of the channel measured for the different time symbols of information elements received from the received signal corresponding to the same information element and according to interference due to said waveform.

Advantageously and according to the invention:

in a second step, a mean of mutual information is elaborated for each coded word of the received stream of code words, by averaging the different mutual information values 1 ^ elaborated in the first step for the different values taken by said transmission quality Qk on said code word,

in a third step, at least one value of an error rate ER of the received stream of bits is elaborated without performing the decoding for each coded word of the received stream of code words, from each value of the average of mutual information developed in the second step, and using stored data representative of variations of an equivalent error rate according to at least one function, called standard function, of the signal / noise ratio, each standard function being predetermined for coding and decoding devices on an additive Gaussian white noise channel.

In a completely unexpected manner, the inventors have indeed found that it is possible to use such a signal-to-noise ratio plus equivalent interference as a measure of the quality of transmission in the context of the performance prediction applied to the forms. of the subsequent steps of the method of predicting performance using the mutual information can be strictly unchanged, as described by FR 2 952 254. Indeed while in the method of FR 2 952 254, the transmission quality is calculated for each part of a received codeword corresponding to the received modulated symbols for which the attenuation of the channel remains the same, it turns out that it is possible for single carrier cyclic waveforms, using a signal-to-noise ratio plus equivalent interference for each information element received from different measured signal-to-noise ratio values for the different time symbols of information elements received from the received signal corresponding to this information element and according to the interference due to said waveform.

The calculation of the signal-to-noise ratio plus equivalent interference is chosen according to the invention as a function of the waveform adopted and the equalization method implemented.

In particular, the equalization method may be the subject of various variants (minimized mean square error equalization (MMSE) or Wiener filter, zero forcing equalization (ZF), ...).

The invention applies more particularly (although not exclusively) to single-carrier cyclic waveforms comprising a fast Fourier transform applied to the time symbols of the received signal to produce blocks received at M frequency components. With these waveforms, the information elements are distributed over the different frequency components of the received blocks. The invention applies even more particularly to those waveforms for which the equalization method is applied to the blocks received at M frequency components (in the frequency domain). Indeed, in this case, the equalization process is greatly simplified.

Advantageously and according to the invention, said waveform being chosen from the group of frequency-division single-carrier waveforms over a plurality of sub-carrier Ms, the received signal having time symbols of N elements of modulated information, N being an integer greater than M, said time symbols being separated from each other by guard intervals, the receiving device being adapted to:

- delete the guard intervals,

applying a fast N-order Fourier transform to the time symbols of the received signal, and producing blocks, called received blocks, of frequency components on said sub-carriers, applying said equalization method to said received blocks to produce equalized blocks,

applying a fast inverse Fourier transform to the equalized blocks to produce a stream of equalized time symbols,

digital data are stored making it possible to determine a value of a signal-to-noise ratio SNRi for each frequency component of a received block,

said transmission quality consists of the same value SINReq of a signal-to-noise ratio plus equivalent interference calculated as a function of said equalization method from said values of signal-to-noise ratios SNRi for all the frequency components s of a same block received.

In an advantageous embodiment of the invention, the received signal having a SC-OFDM waveform without weighting, said value SINReq of the signal / noise ratio plus equivalent interference is calculated according to the following formula (I):

(I) IF ² and in which:

H [h] is the gain of the channel calculated by discrete Fourier transform of a discrete impulse response,

- W [k] is the transfer function of the equalization and weighting method, and W [k] = W [k] H [k],

- y is the average signal-to-noise ratio (in time / frequency).

More particularly, advantageously and according to the invention, said equalization method being minimally squared (MMSE) or Wiener filter, said value SINReq of the signal / noise ratio plus interference equivalent is calculated according to the following formula (II) (II) SINReq = y ^ T?

M-

y _k = Mk] \ ² _Y

In another advantageous embodiment of the invention, the received signal having an EW-SC-OFDM waveform comprising a frequency extension with weighting, said SINReq value of the signal / noise ratio plus equivalent interference is calculated according to the formula (III) following:

SINReq =

W ₀ [k] \ ²

W ^ k}] ² + \ W ₂ [k]

and in which:

- I ₀ is the central band of the unweighted frequencies (non-recombination of the sub-carriers), is formed of the bands; and 7; _-2 end of the weighted frequencies (where the subcarriers are recombined), the low band IJ.J being referenced by an index 1, the high band 7; _2 by an index 2,

H [k] is the gain of the channel calculated by discrete Fourier transform of a discrete impulse response,

- W [k] is the transfer function of the equalization and weighting method, and W [k] = W [k] H [k], - W ₀ [k]: is the transfer function of the equalization and weighting process in the central frequency band I ₀ corresponding to the neutral weighting (no recombination of the subcarriers),

Wj [k] and W ₂ [k] are the transfer functions of the equalization and weighting method respectively in the two frequency bands IJ.J and Ij_ ₂ where the sub-carriers are recombined and weighted,

- γ is the average signal-to-noise ratio: y = - | - ΙΕΠ Xik] \ ² } ~ M <?

with ^{Λ v} · ^{■ J!} - ^Λ

More particularly, advantageously and according to the invention, said equalization method being minimally averaged (MMSE) or Wiener filter, said value SINReq of the signal / noise ratio plus equivalent interference is calculated according to the following formula (IV) :

(IV) SINReq =

1 - a

Moreover, according to one possible and advantageous variant of the invention, each mutual information value 1 ^ is determined according to the function defined by the following formula (V):

_(V) I _k {x _k , y _k ) = - \ og ₂ {œSINR _eq ) - J jf (u, v) \ og ₂ (f (u, v)) dudv u = -∞ v = -∞

1

S ^* m - IS ¹ m

M being the cardinal of the alphabet ^ ^- {^ Ό _' ^ Ί''''' ^ -li modulated symbols.

Advantageously and according to the invention, this analytical formula can be discretized for its evaluation by digital processing, for example according to the function defined by the following formula (VI):

I _k (x _k , y _k ) = - \ og ₂ (SINR _eq )

threshold threshold

(VI) -AuAv Σ Σf (qAu, rAv) \ og ₂ (f (qAu, rAv))

q = - threshold r = - threshold

threshold = + Max, _≤m≤M _ _x (real (SINR _eq S _m ), imag (SINR _eq S _m ))

. . . threshold

and Au = Av = 2

β

According to another possible and advantageous variant of the invention, each mutual information value 1 ^ is determined according to the function I ^ b ¹ k, yt) of the mutual information computed between the j th bit (^ ^{≤ J≤ p _1} ) of the emitted symbol and the received symbol y ^ this function being defined by the following formula (VII):

(H> y _k ) = - \ \ f (, v) log ₂ (f (u, v)) dudv

= -O γ = -ο

+ {\ g _j (u, v) log ₂ (g _j (u, v)) dudv

H y = -

M being the cardinal of the alphabet A ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ £ _as all standardized symbols S _m of bits p j≤ 0≤ p - 1 ^ _e ^ Y _have number m is 0, £ _as all standard p-bit symbols

0≤ j≤ p - 1 ^ _have Y _e ^ numbered m is 1.

Advantageously and according to the invention, this analytical formula can be discretized for its evaluation by digital processing, for example according to

the function defined by the following formula (VIII):

threshold

(by _k = Σ / (qAu, rAv) log ₂ (/ (qAu, rAv))

r = - threshold

threshold threshold

⁺ Σ ^{^} Σ _i 8 _j (q ^ u, rAv) \ og ₂ (g _j (qAu, rAv))

threshold r threshold

threshold = + Max _0≤k≤M _ ₁ (real (SINR _eq S _k ), imag (SINR _eq S _k ))

. . . threshold

and Au = Av = 2

β

Furthermore, advantageously and according to the invention, the values of SNRi signal-to-noise ratios for each subcarrier are values measured over time, in particular by the receiver, as reception of the symbols received from the signal takes place. received.

Furthermore, advantageously and according to the invention, the mutual information values 1 and / or the mutual information mean and / or each error rate ER of the received bit stream is (are ) developed by the receiver. Furthermore, advantageously a method according to the invention is also characterized in that a deinterleaving is performed after demodulation of the symbols of the received stream of modulated symbols so as to form each coded word of the received stream of coded words, and in that each mutual information value 1 ^ and / or the mutual information mean and / or the error rate ER of the received stream of bits is elaborated for each coded word obtained at the end of such a deinterlacing.

In addition, advantageously and according to the invention, for each coded word of the received stream of coded words, a control signal of the decoding device is elaborated as a function of each value of the error rate ER of the received stream of bits.

Advantageously and according to the invention, for each coded word of the received stream of coded words, a single value of the error rate ER of the received stream of bits is developed from a single standard function, and the control signal is adapted. to activate the decoding device if said value of the error rate ER of the bit stream received is less than a predetermined threshold value.

As a variant, advantageously and according to the invention, for each coded word of the received stream of coded words, a plurality of series of values of the error rate ER of the received stream of bits are elaborated from a plurality of standard functions, each standard function corresponding to a decoding method chosen from a plurality of predetermined decoding methods, and said control signal is designed to activate the decoding device according to the decoding method for which said value of the ER error rate of the received stream of bits is the closest to a predetermined threshold value while being lower than this threshold value.

Advantageously and according to the invention, the decoding methods of the same plurality of decoding methods differ from each other only by a number of decoding iterations.

The invention also extends to a receiver for encoded and modulated serial digital transmission over a non-stationary attenuation attenuated channel, comprising: a reception device adapted to receive a signal, said received signal, incorporating a stream of time symbols of information elements corresponding to a stream of temporal symbols of information elements transmitted on said channel and representative of elements of information corresponding to the data to be transmitted, each information element being represented by a plurality of said time symbols, the received signal having a waveform selected from the group of cyclic waveforms comprising repeated guard intervals cyclically, and say single-carrier, with fluctuations corresponding to those of a single carrier,

an equalization device applying a predetermined equalization method to the time symbols of received information elements,

a demodulation device adapted to generate at least one stream of coded words, said received stream of coded words, from the stream of temporal symbols of received information elements,

a decoding device adapted to generate a bitstream, said received bit stream, by decoding each received stream of coded words, according to a decoding method corresponding to a coding method implemented at the emission of the transmitted stream; symbols modulated on said channel,

a channel performance prediction device adapted to produce at least one representative value of an error rate ER of the received bit stream, without performing the decoding, from stored digital data enabling a quality value to be associated; transmission to the received information elements, said channel performance prediction module being adapted to:

in a first step, elaborating for each value of said transmission quality, a mutual information value according to a predetermined function of said transmission quality,

characterized in that said channel performance prediction device is adapted to use as a transmission quality value, a signal-to-noise ratio plus equivalent interference calculated according to said equalization method from different signal / signal ratio values. measured channel noise for different symbols received from the received signal corresponding to the same information symbol and according to interference due to said waveform.

A receiver according to the invention is also advantageously characterized in that it is suitable for the implementation of a method according to the invention.

Thus, in a first possible and advantageous embodiment of the invention, said channel performance prediction device is adapted to elaborate each mutual information value 1 ^ according to the function defined by the formula (V).

Advantageously and according to the invention, said performance prediction device is adapted to discretize this analytical formula for its evaluation by digital processing, that is to say to elaborate each mutual information value 1 ^ according to the formula (VI) .

In a second possible and advantageous embodiment and according to the invention, said device for predicting the performance of the channel is adapted to elaborate each value of mutual information 1 ^ according to the function defined by the formula (VII).

Advantageously and according to the invention, said device for predicting the performances of the channel is adapted to discretize this analytical formula for its evaluation by digital processing, that is to say to elaborate each value of mutual information. mutual information calculated between the j th bit (^ ^{≤ J≤ p ~} ) of the transmitted symbol and the symbol

received y _k , this function being defined by the formula (VIII).

A receiver according to the invention is also advantageously adapted to measure the SNRi signal-to-noise ratio values for each subcarrier over time as the received symbols of the received signal are received.

Advantageously and according to the invention, said module for predicting performance of the channel is also suitable for: - in a second step, developed for each codeword of the received stream of codewords, an average mutual information, by averaging different mutual information values 1 ^ determined in the first step to the various values taken by said transmission quality on said coded word,

in a third step, for each coded word of the received stream of coded words, elaborating at least one value of the error rate ER of the stream received from bits of each value of the mutual information average determined in the second step, and using stored data representative of variations of an equivalent error rate according to at least one function, called standard function, of the signal-to-noise ratio, each standard function being predetermined for the coding and decoding on an additive Gaussian white noise channel.

Advantageously and according to the invention, said performance prediction device is adapted to elaborate the mutual information values Tjt and / or the mutual information mean and / or each error rate ER of the stream received bits for each coded word from a de-interleaver module of the demodulation device.

In a first embodiment of a receiver according to the invention, said performance prediction device is adapted to elaborate, for each coded word of the received stream of coded words, a control signal of the decoding device according to each value. the error rate ER of the received stream of bits. Advantageously and according to the invention, said channel performance prediction device is adapted to elaborate, for each coded word of the received stream of code words:

a unique value of the error rate ER of the received stream of bits from a single standard function,

and said control signal for activating the decoding device if said value of the error rate ER of the received stream of bits is less than a predetermined threshold value.

In a second embodiment of a receiver according to the invention, said device for predicting the performance of the channel is adapted to elaborate, for each coded word of the received stream of coded words:

a plurality of series of values of the error rate ER of the stream received from bits of a plurality of standard functions, each standard function corresponding to a decoding method chosen from among a plurality of predetermined decoding methods,

and said control signal so as to activate the decoding device according to the decoding method for which said value of the error rate ER of the received stream of bits is the closest to a predetermined threshold value while being lower than this threshold value.

The invention extends to a coded and modulated serial digital transmission device on a nonstationary attenuation attenuated channel between:

an emitter comprising:

^■ a modulation device adapted to generate at least one modulated information element stream, said flux emitted pieces of information modulated in a predetermined modulation scheme, on at least one carrier signal, each flux emitted d modulated information elements being representative of at least a part of each transmitted stream of codewords,

^■ a transmitting device, on a noisy channel in nonstationary attenuation, a transmitted signal incorporating a flow of time symbols of data elements corresponding to the data to be transmitted, each data element being represented by a plurality of temporal symbols, the emitted signal having a waveform selected from the group of cyclic waveforms comprising cyclically repeated and single-carrier guarding intervals having fluctuations corresponding to those of a single carrier,

- and a receiver comprising:

^■ a receiving device adapted to receive a signal, said signal received, incorporating a stream of time symbols of information elements corresponding to a stream of time symbols of information elements transmitted on said channel,

^■ an equalization device applying a predetermined equalization process to the temporal symbols of information received,

^■ a demodulation device adapted to generate at least one stream of codewords, said received stream of code words, from the stream of time symbols of information received,

^■ at least one decoding device adapted to generate a bit stream, said received stream of bits, for decoding each received stream of codewords according to a decoding method corresponding to a coding method implemented by the transmitter, characterized in that the receiver is in accordance with the invention and / or implements a method according to the invention.

The inventors have found that the invention makes it possible in practice to obtain a fast and accurate performance prediction, and in particular considerably more accurate than in all the known prior methods, while remaining so fast. This result is surprising, in particular because the signal-to-noise ratio plus equivalent interference does not correspond to the transmission quality per modulated information element received.

Moreover, these advantages provided by the invention make it possible to envisage its real-time use at a receiver for single-carrier cyclic waveforms (notably SC-OFDM, EW-SC-OFDM, SC-FDMA , WCP-OFDM, cyclic TDM) to optimize its operation, and in particular to determine whether or not a received coded word must be decoded and, if appropriate, the minimum number of iterations to be used by the decoding module, in the case where the latter is of the iterative type (LDPC, turbocode ...).

Thus, the invention makes it possible to envisage the production of a receiver for these waveforms whose performances are auto-adaptive and minimized as a function of the quality of transmission. Such a receiver has the particular advantage of having a minimum energy consumption which is a considerable advantage for receivers embedded on mobile systems, in particular on space systems. Indeed, the reduction of energy consumption makes it possible on the one hand to save money in use, and on the other hand to minimize the performance requirements of the energy sources, and therefore their costs, their weight and their size. , or improve their operating life when it comes to a storage battery.

The invention extends to a non-stationary coded serial digital transmission method incorporating a reception method according to the invention, as well as to a non-stationary channel coded serial digital transmission device comprising a receiver according to the invention. .

The invention extends to a computer program capable of being loaded into the RAM of a computing device, and comprising program code instructions for the execution of the steps of a method according to the invention by the said computer device.

It also extends to a computer program product comprising program code instructions recorded on a medium that can be used in a computer system, characterized in that it comprises programming means readable by a computer system for executing a method according to the invention.

The invention also relates to a reception method, a receiver, a transmission method, a transmission device characterized in combination by all or some of the characteristics mentioned above or below.

Other objects, features and advantages of the invention will appear on reading the following description which refers to the appended figures representing, by way of non-limiting examples, embodiments of the invention and in which:

FIG. 1 is a block diagram showing a transmission device according to the invention incorporating a receiver according to the invention,

FIG. 2 is a block diagram showing a transmission device of a transmission device according to the invention, FIG. 3 is a block diagram showing a reception device and a device for predicting the performance of a receiver according to the invention,

FIG. 4 is a schematic flow chart showing an embodiment of a reception method according to the invention,

FIG. 5 is a diagram illustrating an example of the appearance of received time symbols and the duration of the coded words and time symbols received in a single carrier cyclic waveform,

FIG. 6 is a diagram illustrating an example of values of the equivalent signal-to-noise plus interference ratio calculated on the time symbols received from FIG. 5;

FIG. 7 is a diagram illustrating the operations carried out in the frequency domain with an EW-SC-OFDM waveform,

FIG. 8 is a schematic diagram of examples of reference curves that can be used, according to different modulation schemes, for a predetermined function for determining a mutual information value on a Gaussian white noise additive-dependent channel. the signal-to-noise ratio of this channel,

FIG. 9 is a schematic diagram showing the use of a reference curve similar to FIG. 8 for executing a step of a method according to the invention,

FIG. 10 is a schematic diagram showing the use of a reference curve similar to FIG. 8 for carrying out a first part of a step of a method according to the invention,

FIG. 11 is a schematic diagram showing the use of a curve representative of a standard function for performing a second part of a step of a method according to the invention,

FIG. 12 is a diagram illustrating the transmission and reception chain of a cyclic waveform with a single carrier in the time domain (TDM type), FIG. 13 is a diagram illustrating an example of PER obtainable by a method according to the invention compared to an estimated value in the case of a non-frequency selective channel,

FIG. 14 is a diagram illustrating an example of PER obtainable by a method according to the invention compared to an estimated value in the case of a frequency selective channel.

FIG. 1 generally represents a coded and modulated serial digital transmission device on a non-stationary attenuation attenuated channel with an EW-SC-OFDM waveform. This device comprises a transmitter 11, a receiver 12 and a physical link 13 wireless forming the transmission channel. The physical link 13 may for example be a radio frequency link, such as for example linking mobile terminals such as cellular telephones, personal digital assistants, laptops, wireless cards, land vehicles, ships, aircraft, satellites, space probes or other space systems ... at a base station, itself fixed (terrestrial) or mobile (vehicle, satellite, ...) accessing a data transmission network such as the Internet network or any other private network. In general, the transmission can be bidirectional, that is to say that each mobile terminal is sometimes issuer, sometimes receiver.

The transmitter 11 comprises a first module 14 delivering data in the form of a bit stream (baseband signal) to be transmitted, said transmitted bit stream. This transmitted bit stream is supplied to a coding module which executes a predetermined coding method to form, from the bits, a stream of coded words, the so-called coded word stream. Such a coding method makes it possible in particular to increase the reliability of the transmitted data by increasing the redundancies while ensuring the correction of errors, that is to say the restitution of the initial data despite the disturbances that can undergo the channel 13 of transmission.

The invention applies to any coding method, and regardless of the exact nature of the coding method used. This may be in particular a coding method chosen from the so-called LDPC type hollow parity matrix), turbo-type methods and other iterative decoding coding methods. In most modern coding methods that achieve performance near the Shannon limit, the coding module comprises a plurality of coders-notably two coders.

Thus, the coding module 15 delivers coded words, which are then interleaved by an interleaver circuit 17, and then modulated, according to a predetermined modulation scheme, by a modulator circuit 18 which provides a stream of modulated and interleaved information elements. to a transmission device 19 capable of radiofrequency transmission on the physical link 13 of the signals in the form of time symbols of N information elements.

The receiver 12 comprises a reception device 20 able to receive the signals transmitted via the physical link 13 by radiofrequency, and to deliver a stream of temporal symbols of received modulated and interleaved information elements, to a device able to apply a demodulation according to the modulation scheme and mapping used on transmission, then a de-interleaver circuit 22 which performs the inverse processing of the interleaver 17 of the transmitter 11, that is to say, allows the progressive reconstitution of a stream temporal symbols deinterleaved demodulated information elements, from the flow of time symbols of information elements from the demodulator circuit 21. The deinterleaver circuit 22 thus provides a stream of coded words, said stream received code words, from the stream of demodulated deinterleaved information elements. These received coded words are then supplied to a buffer memory 23 and then progressively processed by a decoding module 25, comprising one or more decoders (in particular two decoders), and making it possible to deliver a stream 27 of received bits included in the decoder. signal conveyed by the physical link 13 and corresponding to the stream of bits emitted by the generator circuit 14.

The receiver 12 also comprises a performance prediction module 28 described hereinafter in more detail.

FIG. 2 shows in more detail the transmission device 19 in the case of an EW-SC-OFDM waveform with M subcarriers (M being an integer greater than 1, and generally of the order of several hundred, for example equal at 426). This waveform is known in itself and described for example by the publication "MMSE Frequency-domain Equalization Using Spectrum Combining for Nyquist Filtered Broadband Single-Carrier Transmission" [S. OKUYAMA], 2010.

This transmitting device 19 firstly comprises a module 51 putting in parallel the modulated and interleaved information elements and applying a fast Fourier transform to them, to deliver blocks with M frequency components on the different sub-carriers. The transmission device 19 also comprises an expansion module 52 receiving the blocks delivered by the module 51 to apply to them an extension of K subcarriers, namely K / 2 subcarriers in the bands. and, respectively, 7; _-2 (FIG. 7) at each end of the central frequency band ₁₀ of the subcarriers, K being a non-zero integer less than M, for example of the order of 10% of M, for example equal to 42.

The transmission device 19 also comprises a driver insertion module 53 in a deterministic manner, intermingled or not with the subcarriers carrying information, also adding subcarriers of zero value at both ends of the spectrum, so to deliver blocks with N frequency components, N being a non-zero integer greater than M + K, for example of the order of 512.

The transmission device 19 also comprises a module 54 for weighting the subcarrier K by application of a Nyquist half-filter in the frequency domain whose transfer function is for example:

where a is the drop-off coefficient (roll-off factor) of the Nyquist filter, and M is the number of subcarriers carrying information.

The blocks with N frequency components delivered by the weighting module 54 are subjected to a module 55 applying to them a transform Fast Fourier counter then a parallel / serial transformation to deliver time symbols of N information elements. These time series symbols are processed by a module 56 inserting guard intervals (cyclic prefixes corresponding to a part of the copied symbols) between the symbols, and the signal obtained is transmitted on the transmission line 13 by a transmission circuit 57 comprising a digital-to-analog converter and a radiofrequency transmitter connected to a transmitting antenna.

The reception device 20 comprises a reception circuit 61 comprising an analog / digital converter and a radio frequency receiver connected to a reception antenna, making it possible to receive signals transmitted by a transmission device 19 and comprising temporal symbols h (n). N modulated and intertwined information elements. The received temporal symbols are processed by a module 62 removing the guard intervals between the symbols, and supplying temporal symbols at the input of a module 63 placing the modulated and interleaved information elements in parallel and applying them a fast Fourier transform to deliver blocks Y (K) received at N frequency components (step 29 figure 4).

These received blocks Y (K) are supplied to the input of an equalization module 64 applying a predetermined equalization method W (K) in the frequency domain, and to the input of a module 65 for the desorption of K subcarriers extension. The equalized and unweighted blocks obtained are then supplied to the input of a module 66 suppressing the extension and thus delivering blocks with M frequency components at the input of a module 67 which removes the pilots from the symbol stream. information.

The blocks Ye (K) received at M frequency components thus obtained are delivered to the input of a module 68 applying them an inverse fast Fourier transform then a parallel / series transformation to deliver modulated x (n) information elements. and interlaced at the input of the demodulator 21, which provides demodulated and interleaved information elements at the input of the deinterleaver 22, the latter providing demodulated information elements and interleaved.

The left-hand part of FIG. 4 illustrates the various steps performed by the receiver 12. The step 31 FIG. 4 represents the set of operations performed by the equalization module 64, the de-weighting module 65, the module 66 suppressing the extension, the module 67 for removing the pilots, and the module 68 applying a fast inverse Fourier transform to deliver information elements x (n) from the blocks Y (K) received at M frequency components. In the subsequent step 40, the received stream of code words is demodulated by the demodulator 21. It is then deinterlaced by the deinterleaver 22 in the subsequent step 32, then stored in the buffer 23 in step 41 .

The performance prediction module 28 performs the steps illustrated in the right-hand part of FIG. 4. FIG. 4 thus represents a flow diagram of an exemplary reception method according to the invention implemented in a receiver 12 according to the invention.

The performance prediction module 28 receives the blocks Y (K) received at N frequency components at the output of the module 63 applying a fast Fourier transform in reception. From these blocks Y (K), this module determines in step 30, a signal / noise ratio y = SNRi for each frequency component of a received block, and for the different time symbols of information elements received from the received signal corresponding to the same piece of information. This calculation is carried out on all the sub-carriers used for the fast Fourier transform (module 51) on the emission (EW) -SC-OFDM.

From these stored values SNRi signal / noise reports of each useful frequency component of a received block, the performance prediction module 28 calculates in step 33, for each piece of information, according to the method of equalization, and according to the interference due to the waveform, a ratio SINReq signal / noise plus interference equivalent according to the equalization process. In the example shown in the figures of an EW-SC-OFDM waveform, said value SINReq of the signal-to-noise ratio plus equivalent interference is calculated according to the formula (III).

For example, in the case of a minimized mean squared error (MMSE) or Wiener filter equalization method, the transfer function of the equalization filter is given by: wm

s γ! _j kj ~ -? - ^ H [] s ~}

yk €

wjfc] = - - _T - E / _X

( ^] ¾MI ² + | ¾ [/ i]) + ⁱ

With H (k) = H [k] F [k], the gain of the global channel which takes into account the gain H [k] of the channel (discrete Fourier Fourier transform of the discrete impulse response) and the window weighting F [k] applied to the transmission.

The SINReq value of the signal / noise ratio plus equivalent interference is therefore given by the formula (IV).

FIG. 5 represents an example of time symbols received of duration Ts corresponding to a coded word of duration Tmc with such a waveform. FIG. 6 represents an example of SINReq values of the signal-to-noise ratio plus equivalent interference that can be obtained with the formula above. As can be seen, these values are established while the duration Tmc of a coded word does not correspond to a multiple of the duration Tei of the information elements received for this coded word.

In the case of a SC-OFDM waveform without weighting, said value SINReq of the signal-to-noise ratio plus equivalent interference is given by the formula (I). For example, in the case of a minimized mean square error (MMSE) or Wiener filter equalization method, the transfer function of the equalization filter is given by:

The SINReq value of the signal / noise ratio plus equivalent interference is therefore given by the formula (II).

In the case of a zero forcing (ZF) type equalization method, the transfer function of the equalization filter is given by the following formula (IX):

1

(IX) SINReq = -

M-l

1 1

PY _k = \ [k] \ ² _Y

In the case of a TDM-type temporal waveform, the transmission and reception chain, including the transmission channel, is represented in FIG.

- M and N represent natural integers in the meaning is similar to those mentioned above for a waveform EW-SC-OFDM (complex symbol grouping)

- L corresponds to the interpolation factor = N / M,

- CP corresponds to the addition of the cyclic prefix (cyclic copy of part of the N samples),

h _T (n) is a temporal Nyquist filter,

h _c (n) is a filter representing the propagation channel,

- W (n) is a temporal equalization filter. It can be shown that the expression of the signal-to-noise ratio plus equivalent interference SINReq is the same as for the frequency domain (formula (III) above) by taking:

h (n) = h _T (n) (g) h _c (n) with (g) circular convolution operator,

- H [k] is the discrete Fourier transform of {h (n)},

- W [k] is the discrete Fourier transform of {w (n)}.

The performance prediction module 28 makes it possible to determine an error rate, before the decoding (and therefore without requiring the latter to be performed), for each piece of information received, taking into account the attenuation variations of the channel on the channel. the pieces of information received, that is to say on the different parts of the corresponding received coded words. The method implemented for this purpose may be identical to that described in FR 2 952 254.

In step 33, the different values SINReq representing the transmission quality are calculated by the performance prediction module 28 from the received stream of codewords, for each piece of information of a corresponding received codeword. stored in the memory 23, the received stream of codewords.

From these different values SINReq, a mutual information value 1 ^ is developed by the performance prediction module 28, in the subsequent step 34, according to a predetermined function.

Two variants of the invention are possible with regard to the choice of the predetermined function for the calculation of said mutual information value 1 ^.

If we consider an information element received y, this information element corresponds to the information element emitted attenuated by and noisy by an additive Gaussian white noise. Due to the chosen modulation of cardinal M = 2 ^P , b ^k ₂ ..

A first variant embodiment of the invention consists of consider mutual information 7 ((b ^k ₁ , b ^k ₂ ,., b ^k _p ), y ^) equal to mutual information

Ik between the transmitted information element and the received information element y ^. This variant has the advantage of proposing a unique theoretical formula for calculating a reference curve of the mutual information which depends solely on the nature of the modulation considered. This approach does not take into account the actual implementation ("mapping") of the modulation nor the fact that the constituent p bits of the information element are not all protected in the same way against the noise of the channel.

In this first variant, each mutual information value 1 ^ is determined according to the function defined by the aforementioned formula (I).

The expression def (u, v) is in analytical form and can therefore be evaluated for all values of u and v. For the integral, it is enough to discretize this integral by any numerical method. For example using a method of rectangles, we obtain each mutual information value 1 ^ according to the function defined by the formula (VI).

As can be seen, for a given modulation, a channel attenuation and a known noise spectral density, the mutual information between the transmitted and received information elements depends only on the value of the SINReq signal / noise plus equivalent interference ratio. .

A reference curve for each modulation scheme can therefore be obtained by numerical evaluation of the previous expression. For example, the reference curves shown in FIG. 3 are obtained respectively for the following modulation schemes: QPSK, BPSK, 16QAM, 64QAM.

A second variant consists of taking into account the actual implementation ("mapping") of the modulation and considering each bit. For each of the p bits b \ b ^k ₂ .. b ^k _p constituting the transmitted information element Χ ^, the mutual information ^ (b ^k ₁ , yk), / ^ (b ^k ₂ , yk is calculated ) .... / ^ (b ^k _p , yk) between each bit and the received information element y ^

The reference curve used to obtain the information mutual is then the sum of these p curves.

Thus, in this second variant, each mutual information value I _k is determined according to the function I _k i ^ _b yt) of the mutual information computed between the j th bit - J - P ^) of the element of transmitted information and the information element received y ^, this function being defined by the aforementioned formula (VII).

This general formula (VII) is valid in the case where geometrically these two sets of standardized information elements have the same geometric distribution in the complex plane, that is to say when these two sets are equal to a rotation or translation of the plan. Otherwise, an analytic formula can also be written but it is more complex. The above hypothesis includes PSK modulations in geometric distribution called "Gray mapping".

The expressions df (u, v) and g (u, v) are in analytical form and can therefore be evaluated for all the values of u and v. For the integral, it is enough to discretize this integral by any numerical method. For example using a rectan method, we obtain each value of mutual information 1 ^ according to the function - ¹ ) 'transmitted information element and received information element y ^, this function ^TAA defined by the formula (VIII) with, if one wants to evaluate different Gaussian df (u, v) and gu, v) to at least their probability on a number of points in the mesh β, the following threshold values and (Au, Av): threshold =), imag (SINR _eq S _k ))

. threshold

and Au = Av = 2

β

I _k (^ _k , yk) is between 0 and 1. The reference curve to be used on each piece of information is the sum of the curves for each of the p bits. Whatever the variant used, a reference curve is thus obtained representing a predetermined function providing a mutual information value 1 ^ as a function of a signal-to-noise ratio SNR.

It should be noted that each reference curve referred to throughout the text is in practice materialized by a table of digital values stored in mass memory. The performance prediction module 28 uses such a table to determine the appropriate numerical values allowing the use of such a curve.

In step 34 of calculating mutual information 1, as shown in FIG. 4, the performance prediction module 28 considers the reference curve mentioned above, that is to say the recorded digital values, and each value of the equivalent SINReq signal / noise plus interference ratio as a signal-to-noise ratio value to be plotted as abscissa to determine each value of 1 ^.

In the subsequent step 43, these different values are subjected to the deinterleaving process, and in the subsequent step, for each coded word of the received stream of coded words, a mean of mutual information is developed by averaging the different mutual information values determined for the different values taken by the ratio SINReq signal / noise plus equivalent interference on said coded word.

In the subsequent step 36, the performance prediction module 28 reuses the same reference curve (i.e., the same table of numerical values) to determine an equivalent signal-to-noise ratio SNR _eq on the coded word received from said mutual information mean . In other words, the performance prediction module 28 uses the inverse function

/ * '·

In the subsequent step 37, the performance prediction module 28 calculates each value of the error rate ER from said value of equivalent signal-to-noise ratio SNR _eq and stored data representative of variations of an equivalent error rate according to a predetermined standard function for the coding and decoding modules used on an additive Gaussian white noise channel.

Indeed, for a predetermined coding module 15 and a decoding module 25, there exists a standard function, obtained in a manner known per se by simulation on the stationary Gaussian channel, expressing the error rate per PER coded word or the rate errors per BER bit as a function of the signal-to-noise ratio. FIG. 6 represents an example of curves representative of such standard functions, the different curves being obtained for the same decoding coding modules and varying from one another as a function of the number of iterations used for the decoding.

For each value of the equivalent signal-to-noise ratio SNR _eq , the performance prediction module 28 calculates, from these curves, that is to say tables of corresponding registered digital values, a set of ERi error rates. , i.e., an error rate value for each number of iterations that can be used at decoding. ERi error rate values are decreasing with the number of iterations. This set of values ERi therefore constitutes an error rate vector (ER), determined for each coded word received.

In the example of FIG. 6, four standard function curves are represented: a first curve CS1 corresponding, for example, to a single iteration, a second curve CS2 corresponding, for example, to four iterations, a third curve CS3 corresponding, for example, to eight iterations, and a fourth curve CS4 corresponding for example to sixteen iterations. Thus, from the value of the equivalent signal-to-noise ratio SNR _eq , an error rate vector having four components is obtained: (ER) = (ER1, ER2, ER3, ER4).

It should be noted that the two steps 36, 37 can be combined in one and the same step 38, if the standard functions are combined with the inverse function I ^ ¹ into a single function directly providing, for each number of iterations, curves of variation of the error rate ER as a function of the mean of mutual information .

The received stream of de-interleaved codewords stored in the buffer memory 23 is decoded in step 42 by the decoding module 25 from, in particular, a control signal generated in step 39 from each value of FIG. error rate calculated by the performance prediction module 28.

In a first variant in which the decoding method has a fixed number of iterations that can not be modified by control, the control module of the performance prediction module 28 generates a control signal chosen from among an authorization signal from the decoding and a signal prohibiting decoding. In this case, the performance prediction module 28 calculates a single error rate value ER (PER or BER). In practice, a decoding authorization signal will be developed when the value of the calculated error rate is lower than a predetermined and recorded set error rate, and a decoding prohibition signal will be developed when the value of the rate calculated error is greater than this setpoint error rate value. This variant is particularly interesting especially when the coded block is received on several disjointed time ranges that can spread over a very long period (several seconds in the case of the time dispersal of DVB-SH). It makes it possible to trigger a single decoding by codeword without attempting decoding upon receipt of each new piece of the coded word.

According to a second variant, the performance prediction module 28 also advantageously incorporates a control module making it possible, during step 39, to produce a control signal for the decoding module 25 so that the latter implementing, for each coded word received to be decoded, a number of iterations calculated as a function of the error rates ERi. For example, the control module determines in the ER error rate set the ER _opt value, of the error rate which is the largest and less than a predetermined and recorded set error rate, and controls the error rate. decoding module 25 as a function of the number of iterations corresponding to this value ER _opt .

Figures 13 and 14 are examples implemented with a SC-OFDM waveform with QPSK modulation, M = 512, N = 1024, which show that the PER values obtainable as a function of the signal-to-noise ratio SNRi = Es / No according to the invention (points in the figures ) correspond to values estimated by simulation (curve in the figures), and this as well for a frequency selective channel as for a Gaussian channel.

Such a result was considered until now as impossible to obtain with single carrier cyclic waveforms. In particular, it makes it possible to know the characteristics of the transmission in advance with excellent reliability, without requiring a complete simulation of the physical link itself, and can be used to optimize the design and manufacture of the receiver according to the constraints. of imposed transmission quality (probability in ordinates in the figure), by choosing the maximum signal-to-noise ratio making it possible to respect these constraints. The invention thus makes it possible in particular to avoid any oversizing.

The invention makes it possible to improve by a factor of the order of 500 the average duration necessary for the evaluation with respect to a complete simulator generating the coded packets. An empirical rule indicates that with such a complete simulator, to know the PER (error rate per packet), it is necessary to generate coded packets until 100 packets are false. Thus, for example, for a PER of 0.01, the number of packets to generate to obtain a single value of PER over time, it will generate 10,000 coded words.

Moreover, the tests show that the evaluation according to the invention is on average faster than the real time. In other words, the performances in PER on a channel of duration D will be obtained in a calculation time slightly lower than the duration D.

The main configuration parameters of the simulator are: the type (row-columns, convolutional ...) and the parameters of the de-interleaver to change the parameters as defined in the DVB-NGH standard (interleaving depth, interlace unit (number of symbols) ...); channel settings that allow the user to choose a channel template and modify the parameters associated with this model; the parameters of the physical link that allow the user to modify the parameters of the waveform (guard intervals, band, number of sub-carriers) as well as the coding rate.

The invention can be the subject of many alternative embodiments and applications other than those mentioned above.

Claims

1 / - A method of receiving digital data transmitted over a coded and modulated serial digital transmission over a non-stationary attenuation channel, in which:

a signal, said received signal, is received by a receiving device (12), said received signal incorporating a stream of time symbols of information elements corresponding to a stream of temporal symbols of information elements transmitted on said channel and representative information elements corresponding to the data to be transmitted, each information element being represented by a plurality of said time symbols, the received signal having a waveform selected from the group of cyclic waveforms , including cyclically repeated guard intervals, and said single carrier, having fluctuations corresponding to those of a single carrier,

a bit stream, referred to as a received bit stream, is generated by decoding each received stream of codewords, according to a decoding method corresponding to a coding method implemented on transmission on the channel of the stream; issued symbols, wherein

^■ digital data is stored associating a transmission quality value to the information received,

^■ in a first step (34), a mutual information value 1 ^ is developed for each value of said transmission quality as a predetermined function of said transmission quality,

characterized in that said transmission quality value comprises a signal-to-noise ratio plus equivalent interference calculated according to said method of equalization from different values of signal / noise ratio of the channel measured for the different time symbols of information elements received from the received signal corresponding to the same information element and according to interference due to said waveform .

21 - The method of claim 1, characterized in that said waveform is selected from the group of frequency division single carrier waveforms on a plurality of M subcarriers, the received signal having time symbols N modulated information elements, N being an integer greater than M, said time symbols being separated from each other by guard intervals, the receiving device (12) being adapted to:

- delete the guard intervals,

applying a fast N-order Fourier transform to the time symbols of the received signal, and producing blocks, called received blocks, of frequency components on said sub-carriers,

applying said equalization method to said received blocks to produce equalized blocks,

said transmission quality consists of the same value SINReq of a signal-to-noise ratio plus equivalent interference calculated as a function of said equalization method from said values of signal-to-noise ratios SNRi for all the frequency components of the same block received.

3 / - Method according to claim 2, characterized in that the received signal having an SC-OFDM waveform without weighting, said value SINReq of the signal / noise ratio plus equivalent interference is calculated according to the following formula (I): (I)

with a = Σk = o W [k] H [k]

M

and in which:

- y is the average signal-to-noise ratio (in time / frequency).

4 / - Method according to claim 3, characterized in that said equalization method being minimally averaged (MMSE) or Wiener filter, said value SINReq of the signal / noise ratio plus equivalent interference is calculated according to the formula ( II) next:

β

(II) SINReq =

1 2,

Y _k = \ H [k] \ * _Y

5 / - Method according to claim 2, characterized in that the received signal having an EW-SC-OFDM waveform comprising a frequency extension with weighting, said value SINReq of the signal / noise ratio plus equivalent interference is calculated according to the following formula (III):

kl ²

(III) SINReq =

Σ ^ (\ ννΜ \ ² + _γ → \ ννΜή - \ α \

and in which:

- I ₀ is the central band of the unweighted frequencies (non-recombination of the sub-carriers), is formed of the bands; and 7; _-2 end of the weighted frequencies (where the subcarriers are recombined), the low band /; being referenced by an index 1, the high band I] _ ₂ by an index 2,

- W ₀ [k]: is the transfer function of the equalization and weighting method in the central frequency band I ₀ corresponding to the neutral weighting (no recombination of the subcarriers),

W ₁ [k] and W ₂ [k] are the transfer functions of the equalization and weighting method respectively in the two frequency bands. and 7; _-2 where the subcarriers are recombined and weighted,

- γ is the average signal-to-noise ratio: y 2 with ^{Λ s} - ⁱ - ^■

6 / - Method according to claim 5, characterized in that said equalization method being minimally squared (MMSE) or Wiener filter, said value SINReq of the signal / noise ratio plus interference equivalent shall be calculated according to the following formula (IV):

(IV) SINReq =

1 - a

11 - Method according to one of claims 1 to 6, characterized in that each mutual information value 1 ^ is developed according to the function defined by the following formula (V):

(V) u = -∞ v = -∞

S m - I i S ^ m

M being the cardinal of the alphabet modulated sym oles.

8 / - Method according to one of claims 1 to 6, characterized in that each mutual information value 1 ^ is developed according to the function defined by the following formula (VI):

I _k {^ y _k ) = - ^ g ₂ {mSINR _eq )

threshold threshold

W - AuAv Σ Σf (qAu, rAv) \ og ₂ (f (qAu, rAv))

q = - threshold r = - threshold

threshold = SINR _eq + Max _{Q <} _ _{m <} _ _u _ _x (real (SINR _eq S _m ), imag (SINR _eq S _m )) threshold

and Au = Av = 2-

Method according to one of Claims 1 to 6, characterized each mutual information value is calculated according to the function mutual information computed between the j th bit ( ⁰ J J ^≤ P ^l ) of the transmitted information element and the information element receiving this function being defined by the following formula (VII):

(VII)

+ {g _j (u, v) \ og ₂ (g _j (u, v)) dudv

M being the cardinal of the alphabet } modulated symbols, ^m of p bits

0 <j <p ^ 1 _have _{jth num} e _r Oté m is 0, S i

L m ⁱ o≤m≤2 ^p -1 being the set of standardized symbols ^m of p bits

0≤ j≤ p 1 _have j ^ j _e _t e _r _num Oté m is 1.

10 / - Method according to one of claims 1 to 6, characterized in what each mutual information value

defined by the following formula (VIII):

(threshold threshold

(H, y _k ) = AuAv Σ / {qAu, rAv) log ₂ (/ (qAu, rAv))

- threshold r = - threshold

threshold threshold

⁺ Σ Σg _j (qu, rAv) log ₂ (g _j (qAu, rAv))

threshold r threshold

threshold S _k ), imag (SINR _eq S _k ))

threshold

and Au = Av = 2- β

11 / - Method according to claim 2 and one of the claims

1 to 10, characterized in that the signal-to-noise ratio values SNRi for each subcarrier are measured values as received symbols received from the received signal.

12 / - Method according to one of claims 1 to 11, characterized in that:

^■ in a second step (35), an average mutual information is prepared for each codeword of the received stream of codewords, by averaging different mutual information values 1 ^ produced in the first step for the different values taken by said transmission quality on said coded word,

^■ in a third step (38), at least one value of an error rate ER of the received stream of bits is developed without completion of decoding for each codeword of the received stream of codewords, from each value of the mutual information average developed in the second step, and using stored data representative of variations of an equivalent error rate according to at least one function, called standard function, of the signal / noise ratio, each function standard being predetermined for coding and decoding devices on a channel additive Gaussian white noise.

13 / - Receiver for coded and modulated serial digital transmission over a non-stationary attenuation attenuated channel, comprising:

a receiving device (12) adapted to receive a signal, said received signal, incorporating a stream of time symbols of information elements corresponding to a stream of temporal symbols of information elements transmitted on said channel and representative of information elements corresponding to the data to be transmitted, each information element being represented by a plurality of said time symbols, the received signal having a waveform selected from the group of cyclic waveforms, including intervals cyclically repeated, single-carrier, with fluctuations corresponding to those of a single carrier,

an equalization device (64) applying a predetermined equalization method to the time symbols of received information elements,

a demodulation device (21) adapted to generate at least one stream of coded words, said received stream of coded words, from the stream of received information element temporal symbols,

a decoding device (25) adapted to generate a bitstream, said received bitstream, by decoding each received stream of codewords, according to a decoding method corresponding to a coding method implemented on transmission the emitted stream of modulated symbols on said channel,

a performance prediction device adapted to develop at least one representative value of an error rate ER of the received stream of bits, without performing the decoding, from stored digital data allowing to associate a value of transmission quality to the received information elements, said channel performance prediction module being adapted to:

in a first step, elaborating for each value of said transmission quality, a mutual information value 1 according to a predetermined function of said transmission quality, characterized in that said channel performance prediction device (28) is adapted to use as a transmission quality value, a signal-to-noise ratio plus equivalent interference calculated according to said equalization method from different values of signal / noise ratio of the channel measured for the different symbols received from the received signal corresponding to the same information symbol and according to interference due to said waveform.

14 / - Receiver according to claim 13, characterized in that it is adapted for the implementation of a method according to one of claims 1 to 12.

15 / - Coded and modulated series digital transmission device on a nonstationary attenuation attenuated channel between:

an emitter (11) comprising:

^■ a device (15) for coding adapted to generate, from a bit stream to be transmitted, said transmitted stream of bits, at least one stream of codewords, said flux emitted codeword resulting from the encoding, according to least one predetermined coding method, said transmitted bit stream,

^■ means (18) adapted to generate modulation at least one modulated information element stream, said flux emitted pieces of information modulated in a predetermined modulation scheme, on at least one carrier signal, each transmitted stream of modulated information elements being representative of at least a part of each transmitted stream of coded words,

^■ a device (19) for transmission on a noisy channel in nonstationary attenuation, a transmitted signal incorporating a flow of time symbols of data elements corresponding to the data to be transmitted, each data element being represented by a plurality of time symbols, the emitted signal having a waveform selected from the group of cyclic waveforms comprising cyclically repeated and single-carrier guard intervals having fluctuations corresponding to those a single carrier,

and a receiver (12) comprising:

^■ a device (20) for receiving adapted to receive a signal, said received signal, incorporating a stream of time symbols of information elements corresponding to a stream of time symbols of information elements transmitted on said channel,

^■ means (64) equalization applying a predetermined equalization process to the temporal symbols of information received,

^■ a device (21) adapted demodulation to generate at least one stream of codewords, said received stream of code words, from the stream of time symbols of information received,

^■ at least one device (25) adapted decoding to generate a bit stream, said received stream of bits, for decoding each received stream of codewords according to a decoding method corresponding to a coding method implemented by the 'transmitter,

characterized in that the receiver is according to one of claims 13 or 14.

16 / - A computer device comprising computer means for digital data processing, characterized in that it is adapted and programmed for the implementation of a method according to one of claims 1 to 12.

17 / - Computer program capable of being loaded into the memory of a computing device, and comprising program code instructions for the execution of the steps of a method according to one of claims 1 to 12 by the said computer device.

18 / - Computer program product comprising program code instructions recorded on a medium that can be used in a computer system, characterized in that it comprises programming means readable by a computer system for executing a method according to one of the Claims 1 to 12.