WO2012153732A1 - Dispositif d'étalement, dispositif de communication, dispositif d'émission, procédé de communication et programme - Google Patents

Dispositif d'étalement, dispositif de communication, dispositif d'émission, procédé de communication et programme Download PDF

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WO2012153732A1
WO2012153732A1 PCT/JP2012/061753 JP2012061753W WO2012153732A1 WO 2012153732 A1 WO2012153732 A1 WO 2012153732A1 JP 2012061753 W JP2012061753 W JP 2012061753W WO 2012153732 A1 WO2012153732 A1 WO 2012153732A1
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spreading
time
frequency
signal
code
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PCT/JP2012/061753
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Japanese (ja)
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香田　徹
豊 實松
合原　一幸
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国立大学法人九州大学
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/69—Spread spectrum techniques
    • H04B1/707—Spread spectrum techniques using direct sequence 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
    • H04L27/2626—Arrangements specific to the transmitter 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
    • H04L27/2647—Arrangements specific to the receiver only
    • H04L27/2655—Synchronisation arrangements
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/0001—Arrangements for dividing the transmission path
    • H04L5/0014—Three-dimensional division
    • H04L5/0016—Time-frequency-code
    • H04L5/0017—Time-frequency-code in which a distinct code is applied, as a temporal sequence, to each frequency
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/0001—Arrangements for dividing the transmission path
    • H04L5/0014—Three-dimensional division
    • H04L5/0016—Time-frequency-code
    • H04L5/0021—Time-frequency-code in which codes are applied as a frequency-domain sequences, e.g. MC-CDMA

Definitions

  • the present invention relates to a spreading device, a communication device, a transmission device, a communication method, and a program, and more particularly to a spreading device that can be applied to code division multiple access (CDMA) and the like.
  • CDMA code division multiple access
  • Dispersion of multiple access interference (MAI) in chip asynchronous direct sequence (DS) / code division multiple access (CDMA) system is smaller than in chip synchronous system ,Are better.
  • SS spread spectrum
  • iid independent and identically distributed
  • MAI variance is 1 for chip synchronous systems and chip asynchronous systems Then it is 2/3.
  • MAI is reduced to 1 / ⁇ 3 by replacing the i.i.d. code with a negative correlation code. This phenomenon is reminiscent of the variation reduction technique (ie, the reciprocal variate) in Monte Carlo simulations.
  • the inventors have recently proposed a CDMA (Frequency division-based CDMA: FD-CDMA) system based on frequency division (see Non-Patent Document 1). This was considered as the frequency dual of the chip asynchronous DS / CDMA system.
  • the FD-CDMA system has the important advantage of not requiring frequency synchronization and allowing relative frequency offsets between users.
  • the distribution of MAI in the FD-CDMA system is expressed in the same way as in the DS / CDMA system.
  • the even / odd cross-correlation function for delay l + ⁇ is the double cross-correlation function for delay l and l + ⁇ in both the DS / CDMA system for rectangular waveforms and the FD-CDMA system for sinc waveforms. Is given by the linear superposition of Here, l is an integer, and 0 ⁇ ⁇ 1 is a fraction part.
  • DS / CDMA In the DS / CDMA system, one data section is divided into several small sub-sections of equal length. These are called chips. On the other hand, in the FD-CDMA system, the bandwidth of one data is divided into several frequency subbands. These are called frequency chips.
  • DS / CDMA is referred to as a time division CDMA (time division CDMA: TD-CDMA) system. Table 1 summarizes several communication methods including TD-CDMA and FD-CDMA. Table 1 is described in detail in Non-Patent Document 2.
  • Non-Patent Documents 3 and 4 are the documents of the inventors, and are related to conventional FD-CDMA and TD-CDMA.
  • T.Kohda 1 other person, “Variances of multiple access interference: code average again data average,” Electronics letters, IEE, vol.36, pp.1717-1719, 2000.
  • T.Kohda 3 others, “Frequency division (FD) -based CDMA system which permits frequency offset,” in Proc. of 2010 Int. Sympo. On Spread Spectrum Techniques and Applications, Taichung, Taiwan, Oct. 2010.
  • Y.Jitsumatsu 1 other person, “Quasi-orthogonal multi-carrier CDMA,” in Proc. IEEE Globecom 2008, New Orleans, USA, Nov 2008.
  • T.Kohda “Information sources using chaotic dynamics,” Proc. IEEE, vol.90, no.5, pp.641-661, May 2002.
  • the distribution of MAI decreases in the TD-CDMA system due to time asynchrony.
  • the FD-CDMA system decreases due to frequency asynchrony.
  • conventional approaches have not been able to benefit from both time and frequency offsets.
  • the variance of MAI could only be reduced to 3/5, for example, by using a Gaussian waveform.
  • an object of the present invention is to propose a communication device that can use both time and frequency offsets.
  • a first aspect of the present invention is a spreading apparatus, which spreads a spread signal by a two-dimensional sequence of a time domain spread code and a frequency domain spread code with respect to a time space and a frequency axis simultaneous space of an input signal.
  • a diffusion means for generating is provided.
  • the spreading means includes time spreading means for multiplying the time domain spreading code and frequency spreading means for multiplying the frequency domain spreading code, and a filter signal.
  • Filter means for performing signal processing by using the time spreading means and / or the frequency spreading means generated by multiplying the simultaneous space of the time axis and the frequency axis of the input signal by a code. Signal processing is performed on the processed signal.
  • the simultaneous space is divided into a plurality of cells, and the filter signal has a Gaussian distribution of energy on each cell.
  • the two-dimensional series is a Markov-type two-dimensional PN series independently on a time axis and a frequency axis.
  • a fifth aspect of the present invention is a communication device, which uses a communication signal u GD (t) of equation (eq1) for a simultaneous space of the time axis and the frequency axis of an input signal, and uses a time domain spreading code. And spreading means for generating a spread signal by spreading with a two-dimensional sequence called a frequency domain spreading code.
  • N is the diffusion ratio in the time domain.
  • N ′ is a spreading ratio in the frequency domain.
  • X n is the time domain spreading code.
  • X n ′ is the frequency domain spreading code.
  • v (t) is a chip waveform.
  • T C is a chip interval.
  • W C is the bandwidth of the chip.
  • a sixth aspect of the present invention is a transmission device, which uses a communication signal u (j) GD (t) of equation (eq2) for an input signal of a j-th user, By calculating the equation (eq3) with spreading means for spreading a two-dimensional sequence of time domain spreading code X n, j and frequency domain spreading code X n, j ′ for the simultaneous space to generate a spread signal
  • an integration means for generating the transmission signal s (j) GD (t) by superimposing the spread signal.
  • N is the diffusion ratio in the time domain.
  • N ′ is a spreading ratio in the frequency domain.
  • v (t) is a chip waveform.
  • T C is a chip interval.
  • W C is the bandwidth of the chip.
  • d (j) p, q is an input signal of the p-th time period in the time-frequency domain and the q-th subcarrier for the j-th user.
  • T is a symbol interval.
  • W is the symbol bandwidth.
  • T j is a delay time for the j-th user.
  • v j is the frequency offset for the j th user.
  • the spreading means generates a spread signal by spreading with a two-dimensional sequence of a time-domain spread code and a frequency-domain spread code in the simultaneous space of the time axis and the frequency axis of the input signal.
  • a communication method including steps.
  • the eighth aspect of the present invention is a program for realizing a communication method according to the seventh aspect in a computer.
  • the present invention may be regarded as a computer-readable recording medium for recording the program according to the eighth aspect (steadily).
  • both time and frequency offsets are used by spreading with a two-dimensional sequence of time domain spreading code and frequency domain spreading code.
  • an asynchronous Gabor division (GD) -CDMA system can be realized.
  • This is a multiple access version of Gabor's communication system.
  • This makes both time and frequency offsets available. In that sense, it can be said to be a “double” asynchronous CDMA system (“doubly” asynchronous CDMA system).
  • the time and frequency offset can be adjusted independently.
  • the MAI variance can be reduced to 9/25.
  • FIG. 2 is a diagram illustrating a time-frequency representation of the asynchronous CDMA system of FIG. 1.
  • the power spectrum of two-dimensional SS signal of i.i.d. code and Markov code in GD-CDMA system is shown.
  • FIG. 1 is a block diagram showing an outline of a communication system 1 according to an embodiment of the present invention.
  • the communication system 1 includes a transmission device 3 (an example of “communication device” and “transmission device” in claims of this application) and a reception device 5 (another example of “communication device” in claims of this application).
  • the transmitter 3 and the receiver 5 can be designed in the same way. Therefore, the configuration of the transmission device 3 will be specifically described below.
  • the communication system 1 is a CDMA system in a time-frequency simultaneous space. In this space, the spread signal is expressed as the sum of Gabor basic signals.
  • TD-CDMA and FD-CDMA are combined to define an asynchronous GD system related to time and frequency offsets as equations (1) and (2).
  • the present invention uses Gabor's communication system (see D. Gabor, “Theory of communication,” J. Inst. Electr. En., Vol. 93, pp. 429-457, 1946) in the time-frequency domain. Can be regarded as a multiple access version.
  • There are three levels of time-frequency resolution. The first is the data level. This occupies a large rectangle called T ⁇ W NN ′ >> 1. This is a Gabor cell. According to the Slepian 2WT theorem, a Gabor cell is approximately NN'-dimensional. This level of signal can be easily distinguished.
  • the second is the code level. This occupies an intermediate size square of the area of T c ⁇ W c . This is a micro gabor cell. Microgabor cells are considered to have unit dimensions.
  • FIG. 2 shows a time-frequency representation of the dual asynchronous CDMA system of FIG.
  • the vertical axis is the frequency offset.
  • the horizontal axis is the time offset.
  • the cell 101 is a user 1 Gabor cell.
  • the cell 102 is a Gabor cell of the user 2.
  • Each Gabor cell is represented as (p, q) -Gabor cell using p and q.
  • the cell 105 is a microgabor cell.
  • Each micro Gabor cell has W c in the vertical direction and T c in the horizontal direction.
  • Each micro Gabor cell is represented as (n, n ′)-micro Gabor cell.
  • the cell 107 is a nanogabor cell.
  • Each nanogabor cell is represented as (k, k ′)-nanogabor cell.
  • the transmission device 3 multiplies the data signal by the spread signal in the time domain and the frequency domain.
  • the communication system 1 allows fractional time and frequency offsets. Thereby, the Gabor bundle of each user cannot be arranged in a line. In this case, MAI cannot be expressed as a linear superposition of correlation functions with integer offsets. Therefore, to analyze MAI, an ambiguity function must be used.
  • the ambiguity function is defined as equation (3). This ambiguity function was proposed by Wigner for quantum systems (see E. Wigner, “On the quantum correlation for thermodynamic equilibrium”, Phys. Rev., 1932, pp. 749-759).
  • V (f) is the Fourier transform of v (t).
  • Such ambiguity functions have already been studied and applied to radar systems. In the Fourier transform, the Gaussian waveform has a self-dual characteristic. Therefore, we show that the Gaussian waveform is a strong candidate for the dual asynchronous CDMA system.
  • the normalized dispersion of MAI is 1 in the conventional synchronous CDMA system related to Nyquist (orthogonal) pulses and i.i.d. codes.
  • the dual asynchronous CDMA system of the present invention reduces to 9/25 for non-Nyquist Gaussian waveforms and time-frequency domain Markov SS codes. Further, the present invention has an advantage that time and frequency synchronization is not required between users.
  • FIG. 3 shows the power spectrum of a two-dimensional SS signal of iid code and Markov code in the GD-CDMA system.
  • the expected value and variance of (•) for the random variable Z are denoted as E Z [•] and var Z [•].
  • FIG. 3 shows an average power spectrum of the transmission signal represented by E XX ′ [
  • a negative (or positive) correlated time domain spreading code is a Gaussian spectrum and has the effect of a high pass (and correspondingly low pass) filter.
  • Such high-pass filtered Gaussian spectra overlap each other in a multi-carrier system.
  • the total energy is leveled in the frequency domain due to the negatively correlated frequency domain spreading code, the overlap portion of the spectrum is reduced.
  • the communication device 3 includes an input signal generation unit 11, a diffusion unit 13 (an example of “diffusion device” and “diffusion unit” in claims), and an integration unit 15 (an example of “integration unit” in the claims).
  • the input signal generation unit 11 generates an input signal based on the data signal and gives it to the spreading unit 13.
  • each data signal d (j) p, q is subjected to processing such as giving it at a timing that is easy for the diffusion unit 13 to process.
  • the spreading unit 13 spreads the input signal using the communication signal u (j) GD (t) of the formula (1) to generate a spread signal.
  • the integrating unit 15 generates the transmission signal s (j) GD (t) of Expression (4) by superimposing the spread signal.
  • FIG. 4 is a diagram showing a transmission / reception relationship of each user.
  • the transmitter of each user j generates a transmission signal s (j) GD (t) of Expression (4) from the input signal d (j) p, q .
  • noise n 0 (t) is added in the communication path.
  • the receiver of each user receives the reception signal r GD (t) of Expression (2) and obtains Z (j) p, q ′′.
  • the spreading unit 13 includes a code spreading unit 21 and a filter unit 23 (an example of “filter means” in the claims).
  • the code spreading unit 21 includes a time spreading unit 25 (an example of “time spreading unit” in the claims) and a frequency spreading unit 27 (an example of “frequency spreading unit” in the claims).
  • the time spreading unit 25 multiplies the time domain spreading code.
  • the frequency spreading unit 27 multiplies the frequency domain spreading code.
  • the filter unit 23 performs signal processing using the filter signal.
  • the filter unit 23 uses a filter signal as a signal for the signal generated by the time spreading unit 25 and / or the frequency spreading unit 27 multiplying the simultaneous space of the time axis and the frequency axis of the input signal by a code.
  • a and / or B means at least one of A and B.
  • u (j) GD (t), X n, j , X ′ n ′, j and 2 ⁇ n′W c are respectively expressed as u GD (t), X n , X ′ n ′ and ⁇ . Indicated as n ' .
  • Formula (1) can be described as Formula (5) and Formula (6).
  • 5 and 6 are examples of configurations corresponding to the equations (5) and (6), respectively.
  • the diffusion unit 31 is an example of the diffusion unit 13.
  • Spreading section 31 includes N 'pieces of the signal processing unit 33 0, ..., 33 n' , ..., and 33 N'-1, the sum unit 35.
  • Each signal processing unit 33 n ′ includes a multiplier 41 n ′ (an example of “frequency spreading unit 27” in FIG. 1) that multiplies a frequency domain spreading code, and a Gaussian filter 43 n ′ (FIG. 1) having a center frequency ⁇ n ′ . 1), a sampling unit 45 n ′, and a multiplier 47 n ′ (an example of “time spreading unit 25” in FIG.
  • the Gaussian filter 43 n ′ is for shifting the center frequency at equal intervals.
  • the output signals of the signal processing units 33 0 ,..., 33 n ′ ,..., 33 N′-1 correspond to those having a low frequency to a high frequency.
  • the summation unit 35 performs a delay process or the like on the signal generated by each signal processing unit 33 n ′ to obtain the sum. Thereby, a spread signal can be generated.
  • the diffusing unit 51 is another example of the diffusing unit 13.
  • the spreading unit 51 includes a multiplier 61 (an example of the “time spreading unit 25” in FIG. 1) that multiplies the time domain spreading code, a first filter unit 63 that performs signal processing using the chip signal v (t), It comprises a first summation unit 65 summing performs delay processing, etc., n 'pieces of the signal processing unit 67 0, ..., 67 n' , ..., and 67 N'-1, the second summation unit 69.
  • Each signal processing unit 67 n ′ includes a multiplier 71 n ′ (an example of “frequency spreading unit 27” in FIG. 1) that multiplies the frequency domain spreading code, and a second filter unit that shifts the center frequency ⁇ n ′ at equal intervals.
  • 69 n ′ (a combination of the first filter unit 63 and the second filter unit 69 n ′ is an example of the “filter unit 23” in FIG. 1).
  • the summation unit 35 performs a delay process or the like on the signal generated by each signal processing unit 33 n ′ to obtain the sum. Thereby, a spread signal can be generated.
  • the filter unit 23 in FIG. 1 performs signal processing on a signal multiplied by a time domain spreading code and / or a frequency domain spreading code. This is to apply a band-pass filter with the center time being nT c and the center frequency being n′W c .
  • the Gaussian waveform achieves an equal sign. For this reason, the Gaussian waveform is considered to be an optimal selection as v (t). Gaussian waveforms cause problems with intersymbol and carrier interference at the microcell level. This may be the reason why the Gabor communication system has not been realized in its original form.
  • the inventors adopted a time-frequency spreading code. A data symbol occupies a Gabor cell in N ⁇ N ′ dimensions. Therefore, the determination of the data symbol is simple. Therefore, a Gabor communication system can be realized by spreading codes.
  • Non-Patent Document 3 A CDMA system of a plurality of carriers related to a Gaussian chip waveform has already been proposed by the inventors (see Non-Patent Document 3).
  • frequency synchronization is assumed and only time asynchrony is considered.
  • GD-CDMA system of the present invention it is premised that neither time nor frequency is synchronized. Therefore, GD-CDMA is robust against time-frequency synchronization errors.
  • the MAI of the double asynchronous GD-CDMA system of the present invention is smaller than that of the synchronous CDMA system.
  • the complete definition of TD-CDMA will be explained in detail later.
  • the receiver of the i th correlator of TD-CDMA is decomposed as equation (7).
  • S (i) p is the i-th signal component
  • I (i) J p represents MAI from other J-1 users
  • ⁇ (i) p represents the noise component. Show.
  • TD-CDMA multiple access interference is defined by equation (8).
  • d (j) p, 0 was replaced with d (j) p .
  • u (j) TD (t) will be specifically described later.
  • Equation (10) For a dual asynchronous GD-CDMA system, the output of the correlator for the p th period and the q th subcarrier for the i th user is given by equation (10).
  • S (i) p, q ′′, ⁇ (i) p, q ′′ and I (i) J, p, q ′′ are a signal component, a noise term, and a MAI component, respectively.
  • Theorem 1 Let D (j) be the iid random variable for d (j) p, q .
  • the expected value of the signal component S (i) p, q is E GD
  • the variance of the absolute value of the complex MAI normalized by ⁇ (NN ') and averaged on the iid data D (j) is ⁇ 2 GD
  • equations (11) and (12) hold.
  • E TD , E FD , ⁇ 2 TD, and ⁇ 2 FD are the expected value and variance of the TD- and FD-CDMA systems, respectively. This will be specifically defined later.
  • the nominal micro Gabor cell is further divided into M ⁇ M ′ small regions. These are called nanogabor cells.
  • M ⁇ M ′ small regions These are called nanogabor cells.
  • the idea of using the Wigner distribution described by the energy density in the time-frequency plane was proposed by Ville.
  • Non-Patent Document 4 a rectangular chip pulse was assumed for a chip asynchronous TD-CDMA system.
  • MAI is Equation (17).
  • X up is a series in which X is upsampled M times. It is defined as equation (18).
  • the non-periodic cross-correlation function has the relationship of Equation (19).
  • Equation (19) and the relationship E D (j) [D (j) p D (j) p + 1 ] 0 satisfy Equation (20).
  • E + (l) is, R A N in which;; (X, Y Nl) the variance of divided by N (l X, Y) dispersed and R A N of.
  • F + (l) is the covariance of R A N (l; X, Y) and R A N (l + 1; X, Y) and R A N (Nl; X, Y) and R A N (Nl ⁇ 1; X, Y) is the sum of the covariances divided by N.
  • var XY [I (i) 2, p / ⁇ N] is called MAI code average variance.
  • Equation (21) is established for M >> 1.
  • Equation (21) the code average variance of MAI averaged over K for the chip asynchronous system is 2/3 of the code average variance of MAI for the chip synchronous system. In this sense, it can benefit from the mutual time offset. More importantly, equation (21) suggests that choosing a negative F + (l) can reduce the sign average variance of MAI. This technique is the same as various conventional methods in the dispersion reduction technique.
  • Negative F + (l) can be realized by a Markov code. It is assumed that X 0 ⁇ X 1 ⁇ ... ⁇ X N-1 forms a Markov chain with respect to the state space ⁇ +1, ⁇ 1 ⁇ . The eigenvalue of the transition probability matrix of a Markov chain other than 1 is set to ⁇ 1 ⁇ ⁇ 1. At this time, Equation (23) holds. Therefore, F + (l) is the same as ⁇ . Equation (21) takes the minimum value when ⁇ is ⁇ 2 + ⁇ 3 (see Non-Patent Document 1).
  • the horizontal axis is the frequency offset ⁇ .
  • the vertical axis is the variance of MAI.
  • the MAI code mean variance (dashed line) averaged over k for Markov codes is smaller than that for i.i.d. codes (dashed lines). These averages are N / ⁇ 3 and 2N / 3. These are similarly plotted in FIG. This figure illustrates how the dispersion of MAI can be reduced.
  • the Markov code makes MAI smaller than i.i.d. in a chip asynchronous state (k ⁇ 0).
  • the MAI code mean variance for a general waveform g (t) related to Markov codes can be obtained.
  • Lemma 2 The code average variance of MAI averaged over the iid data D (j) and the fractional delay time K is expressed by equation (24).
  • a, b, and c are Formula (25).
  • the first and second terms of equation (24) are always non-negative, but the third term can be negative. This occurs if c ⁇ ⁇ 0.
  • the minimum value is when ⁇ is in equation (26).
  • the code average variance of MAI for the FD-CDMA system is represented by ⁇ 2 FD ( ⁇ ′). This is defined in Equation (24) by replacing a, b, c and ⁇ with a ′, b ′, c ′ and ⁇ ′, respectively.
  • a ′, b ′, and c ′ are expressed by Expression (27), and ⁇ ′ is an eigenvalue of the frequency domain spreading code.
  • Equation (24) The values of a, b, and c in Equation (24) depend on the chip waveform selection.
  • the sinc pulse in the TD-CDMA system is c ⁇ 0.
  • Table 2 shows the variance of coefficients a, b, and c and MAI for rectangular, sinc, and Gaussian waveforms.
  • Lemma 3 The complex MAI (see FIG. 7) of a two-user dual asynchronous GD-CDMA system is given by equation (28).
  • C A NN ′ (l + ⁇ , l ′ + ⁇ ′) is an aperiodic cross-correlation with respect to a real-valued offset in the time-frequency domain, and is defined by Equation (29).
  • l S is an element of ⁇ 0, 1,..., N ⁇ 1 ⁇
  • k S is an element of ⁇ 0, 1,.
  • the signal component S (i) p is obtained by replacing d (j) p , l, k, and Y up in equation (14) with d (i) p , l S , k S, and X up , respectively. can get.
  • the expected value of the signal component of the receiver regarding the frequency offset ⁇ S is expressed by Expression (30).
  • FIG. 8 shows a simulation result of dispersion of self-interference for FD-CDMA.
  • the horizontal axis is the frequency offset ⁇ s .
  • the vertical axis represents the dispersion of self-interference.
  • This graph is also a graph showing dispersion of self-interference in TD-CDMA by replacing ⁇ S on the horizontal axis with ⁇ S.
  • the variance of the Markov code self-interference (dotted line) is smaller than that of the iid code (solid line). Therefore, the Markov code is superior to iid in terms of self-interference as well as mutual interference.
  • Equation (32) By replacing N, ⁇ S, and ⁇ in Equation (32) with N ′, ⁇ S ′, and ⁇ ′, Equation (32) can be used as the BER estimation of the FD-CDMA system.
  • the ambiguity function is Equation (33) for the Gaussian function and Equation (34) for the rectangle, respectively.
  • the ambiguity function of the sinc function is obtained by replacing ⁇ , ⁇ , and T c in equation (34) with ⁇ , ⁇ , and W c .
  • E TD , E FD , ⁇ 2 TD, and ⁇ 2 FD are Equations (35), (36), (37), and (38), respectively.
  • ⁇ 2 TD and ⁇ 2 FD can be evaluated separately.
  • V (t) is a rectangle in equations (1) and (2).
  • rect Tc (t) is 1 when
  • FD-CDMA is a frequency dual of TD-CDMA.
  • sinc (t) sin ( ⁇ t) / ( ⁇ t).

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Abstract

L'invention porte sur un dispositif de communication ou similaire qui peut utiliser des décalages temporels et fréquentiels. Un dispositif de communication (3) utilise une formule (2) pour générer un signal d'émission (sGD(t)). Une unité d'étalement (13) comporte une unité d'étalement temporel (25) et une unité d'étalement fréquentiel (27). L'unité d'étalement temporel (25) multiplie un code d'étalement de région temporelle (Xn,j). L'unité d'étalement fréquentiel (27) multiplie un code d'étalement de région fréquentielle (X'n,j). Dans la formule (2), τj est le temps de retard pour le jème utilisateur et vj est le décalage de fréquence pour le jème utilisateur. Par autorisation de ces temps et ces fréquences, il est possible d'utiliser des décalages temporels et fréquentiels.
PCT/JP2012/061753 2011-05-10 2012-05-08 Dispositif d'étalement, dispositif de communication, dispositif d'émission, procédé de communication et programme WO2012153732A1 (fr)

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WO2014200089A1 (fr) * 2013-06-13 2014-12-18 国立大学法人九州大学 Procédé de transmission de signaux, et émetteur
WO2015030018A1 (fr) * 2013-08-27 2015-03-05 国立大学法人九州大学 Récepteur, procédé de communication et support d'informations
WO2019142372A1 (fr) 2018-01-22 2019-07-25 ラディウス株式会社 Procédé de réception, dispositif de réception, procédé d'émission, dispositif d'émission, système d'émission/réception
KR20190089850A (ko) 2018-01-22 2019-07-31 라디우스 가부시키가이샤 수신 방법, 수신 장치, 송신 방법, 송신 장치, 송수신 시스템
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