JP2002290274A - Output device for pseudo random number sequence, transmitter, receiver, communication system, filter, output method for the pseudo random number sequence, transmission method, reception method, filter method, program, and information recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a filter or the like which generates a pseudo random number sequence. SOLUTION: An FIR filter 301 with respect to a prescribed real impulse constant r(-1<r<1) receives an input signal of a spread code sequence with a chip length of D at a terminal 305, delay circuits 302 output a plurality of signals delayed respectively by 0. D, 2D, 3D,..., (N-1)D, amplifiers 303 amplify a plurality of signals by an amplification factor of (-r)<1+> T</> D and output the amplified signals, where T is the delay time, and an adder 304 outputs the total sum of the signals that are amplified and outputted, that is, an optimum chaos spread code sequence.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a pseudo-random number sequence output device, a transmitting device, a receiving device, a communication system, a filter device, a pseudo-random number sequence output method, a transmitting method, a receiving method, a filtering method, a program, and The present invention relates to an information recording medium.

[0002] In particular, satellite communications, fixed communications, mobile phones and P
Used as spread code of asynchronous CDMA (Code Division Multiple Access) system of spread spectrum communication which can be used in land mobile communication such as HS (Personal Handyphone System) and ranging field such as GPS (Global Positioning System) Output device and output method suitable for outputting a possible pseudo-random number sequence, and transmission device, reception device, communication system, filter device, transmission method, reception method, and filter method using the same, and a program for realizing these And a computer-readable information recording medium on which the program is recorded.

[0003]

2. Description of the Related Art Conventionally, a linear feedback shift register (LFS) has been used as a spread code for realizing spread spectrum communication and code division multiplex communication.
R), an M sequence, a bulk code, a gold sequence, and the like have been proposed. These spread code sequences have the following two features.

First, the correlation between the same codes (autocorrelation)
Has a single peak, and the correlation (cross-correlation) between different codes is zero. This is very similar to the nature of white noise.

Second, if two different spreading codes included in a code set are selected, and if a code set is configured such that the cross-correlation is close to 0 regardless of which one is selected, the code set is included in the code set. The number of codes is only O (N) for the code length N. Therefore, there are few types of codes.

On the other hand, TDMA (Time Division) has been used for a long time.
Multiple Access (Time Division Multiple Access) and FDMA (Frequ
ency Division Multiple Access (frequency division multiple access) is also known. Asynchronous CDMA communication systems
Unlike these, without actively synchronizing the signals,
It has the characteristic that decoding can be performed using the correlation characteristics of the codes used. For this reason, it is excellent in confidentiality, confidentiality, anti-interference / jam resistance, and the like.

At present, an asynchronous CDMA communication system is being put to practical use, and IMT-2000 (International
l Mobile Telecommunication 2000 (ITU) for next generation wireless communication
n) Adopted as a standard.

[0008] Recent research has shown that in asynchronous CDMA communication systems, the variance σ of intersymbol interference noise determines system performance. This variance σ is represented by K when the number of simultaneously connected users is N and code length is N when pseudo white noise such as a gold code or a bulk code is used as a spreading code.
Then, asymptotically, σ = (K−1) / 3N is disclosed in the following literature, for example. M. B. Pursley, "P
erformance Evaluation for Phased-Coded Spread-Spec
trum Multiple-Access Communication-Part I: System
Analysis ”(IEEE Trans. Communications, vol. 25 (19
77) pp.795-799.)

Here, “asymptotic” means the number of users K
And the code length N is made large.

Conventionally, it has been considered that the theoretical limit of the performance of an asynchronous CDMA communication system is σ = (K−1) / 3N. However, it has also been found that such an asymptotic relationship holds because the spreading code is pseudo white noise.

Therefore, if the spreading code is not pseudo white noise, that is, if there is some correlation between different codes, the theoretical limit of performance may be improved.

Recently, it has been discovered that a spread code having an autocorrelation function such that the variance σ of intersymbol interference noise is reduced as compared with the case where the spread code is pseudo white noise. That is, when the autocorrelation function decreases exponentially with respect to the code shift amount as shown in [Equation 7], the variance σ of the interference noise becomes smaller than that of the pseudo white noise.

[0013]

(Equation 7)

In particular, when the actual impulse constant r satisfies [Equation 8], it takes the form of an optimal correlation function as shown in [Equation 9].

[0015]

(Equation 8)

[0016]

(Equation 9)

This means that the number K of simultaneously connected users at the same bit error rate is 15% larger than the theoretical limit of the number of users of the asynchronous CDMA communication system when pseudo white noise is used as a spreading code. This point is disclosed in the following literature. G. Mazzi
ni, R. Rovatti, and G. Setti "Interference Minimiz
ation by Auto-Correlation Shaping in Asynchronous
DS-CDMA Systems: Chaos-Based Spreading is Nearly O
ptimal ”(Electron. Lett. (1999) vol.35, pp.1054-1)
055)

Further, in the document, it is shown that a correlation function satisfying [Equation 7] can be approximately modeled by forming a chaotic spreading code using a multistage linear mapping having an extremely large partial slope. I have.

[0019]

However, in order to actually generate such a spread sequence using a DSP (Digital Signal Processor) or the like and use it in a mobile phone or the like, high speed and low power consumption are required. Therefore, the following problems have occurred.

First, since the spreading code is composed of a multi-stage linear mapping having an extremely large slope, when calculation is performed by a DSP or a computer, the digit loss is increased and an accurate result cannot be obtained. was there. For this reason, there is a problem that it is difficult to generate a spread code by configuring a physical circuit or device.

Second, there is a problem that a parameter for determining the manner of attenuation of the correlation function cannot be freely adjusted for an arbitrary r (-1 <r <1).

Third, the above literature indicates that there are few types of multistage linear mapping having a correlation function close to the optimal correlation function. However, in order to realize a CDMA communication system, it is better to have as many types of codes as possible. For this reason, it is difficult to actually configure a CDMA communication system by using the method disclosed in the above document.

Fourth, in a spread code generated using a linear shift register, there is only O (N) having a good correlation characteristic with respect to a code length N. The original code type is 2
While there are only numbers O (2 ^N ) proportional to powers of, this is extremely small. For this reason, it is difficult to cope with an increase in the number of users.

Fifth, since the key space is small, the labor required for decryption is small. For this reason, there is a problem that communication security is weakened.

[0025] These problems have not been improved by the technique disclosed in the above-mentioned document.

Therefore, a technique for generating a spread code composed of a pseudo-random number sequence (also referred to as a PN (Pseudo Noise) sequence) suitable for an asynchronous CDMA communication system while solving such problems is strongly desired. I have.

The present invention provides a pseudo random number sequence output device, a transmission device, a receiving device, a communication system, a filter device, a pseudo random number sequence output method, a transmission method, a reception method, and a filter method suitable for an asynchronous CDMA communication system. And a computer-readable information recording medium on which the program is recorded.

[0028]

In order to achieve the above object, the following invention is disclosed in accordance with the principle of the present invention.

The output device according to the first aspect of the present invention comprises a predetermined real impulse constant r (-1 <r <1) and a predetermined real constant
For C (C ≠ 0), a pseudo-random number sequence of length N (N ≧ 1) is output, and includes a sequence receiving unit, a calculating unit, and an output unit, and is configured as follows .

That is, the sequence receiving unit receives an input of a spreading code z [1], z [2],..., Z [L] having a length L (L ≧ 1) as a sequence initial value.

On the other hand, the calculation unit receives the input z [1],
From z [2], ..., z [L], for a given integer M (1 ≦ M ≦ N, M + N <L)

[0032]

(Equation 10) Z '[1], z' [2], ..., z '[N] that satisfy

Further, the output unit outputs z ′ [1], z ′ [2],.
[N] is output as a pseudo-random number sequence.

In the output device of the present invention, the length L
Can be configured to be an M-sequence, a Gold code, a bulk code, a Walsh-Hadamard orthogonal code, or a chaotic code generated by a Chebyshev polynomial.

Further, in the output device of the present invention, the predetermined actual impulse constant r can be configured to satisfy [Equation 8].

[0036] A transmitting device according to a second aspect of the present invention is configured to include a signal receiving unit, the above output device, a spreading unit, and a signal transmitting unit.

Here, the signal receiving unit receives an input of a transmission signal.

On the other hand, the output device outputs a pseudo-random number sequence of length N.

Further, the spreading section spreads the spectrum of the transmission signal received as input using the output pseudo-random number sequence of length N as a spreading code.

Then, the signal transmitting section transmits the signal resulting from the spread spectrum.

Further, the transmitting apparatus of the present invention further includes a selecting section and a parameter transmitting section, and can be configured as follows.

That is, the selection unit sets the spreading code z [1], z
Select [2],…, z [L].

On the other hand, the parameter transmitting section transmits the selected spreading codes z [1], z [2],..., Z [L].

Further, the output device outputs the selected spreading code.
z [1], z [2],..., z [L] are accepted as sequence initial values.

The transmitting apparatus of the present invention further includes a parameter receiving unit, and can be configured as follows.

That is, the parameter receiving unit uses the spreading code
z [1], z [2],..., z [L] are received.

On the other hand, the output device receives the spread code z
[1], z [2],..., Z [L] are accepted as sequence initial values.

A receiving apparatus according to a third aspect of the present invention includes a signal receiving section, the above output apparatus, a despreading section, and an output section, and is configured as follows.

That is, the signal receiving section receives a signal.

On the other hand, the output device outputs a pseudo-random number sequence of length N.

Further, the despreading unit converts the received signal into
Spectrum despreading is performed using the output pseudo-random number sequence of length N as a spreading code.

The output section outputs a signal resulting from spectrum despreading as a transmission signal.

The receiving apparatus of the present invention further includes a selecting section and a parameter transmitting section, and can be configured as follows.

That is, the selection unit sets the spreading code z [1], z
Select [2],…, z [L].

On the other hand, the parameter transmitting section transmits the selected spreading codes z [1], z [2],..., Z [L].

Further, the output device outputs the selected spreading code.
z [1], z [2],..., z [L] are accepted as sequence initial values.

The receiving apparatus of the present invention further includes a parameter receiving section, and can be configured as follows.

That is, the parameter receiving unit uses the spreading code
z [1], z [2],..., z [L] are received.

On the other hand, the output device outputs the received spread code z
[1], z [2],..., Z [L] are accepted as sequence initial values.

[0060] A communication system according to a fourth aspect of the present invention includes the above-described transmitting device and the above-mentioned receiving device, and the receiving device transmits the spread codes z [1], z transmitted from the transmitting device.
[2],..., Z [L], and the receiving device is configured to receive a signal transmitted from the transmitting device.

A communication system according to a fifth aspect of the present invention includes the above-mentioned transmitting device and the above-mentioned receiving device, and the transmitting device transmits the spread codes z [1], z transmitted from the receiving device.
[2],..., Z [L], and the receiving device is configured to receive a signal transmitted from the transmitting device.

A predetermined real impulse constant r (-1 <r <1) and a predetermined real constant C (C ≠ 0) according to the sixth aspect of the present invention,
Has an input terminal, a delay unit, an amplification unit, an addition unit, and an output terminal, and is configured as follows.

That is, the input terminal receives an input of an input signal having a chip length D.

On the other hand, the delay section outputs a plurality of signals obtained by delaying the input signal received by 0, D, 2D, 3D,..., (N-1) D.

Further, when the delay time is T, the amplification section multiplies each of the plurality of delayed signals by C (−r) ^{1 + T / D} , and outputs the result.

The adder outputs the sum of a plurality of amplified and output signals.

On the other hand, the output terminal outputs the added and output signal.

Further, in the filter device of the present invention, the predetermined real impulse constant r can be configured to satisfy [Equation 8].

Further, in the filter device of the present invention, the delay unit, the amplifying unit, and the adding unit include an ASIC (Applicat
ion Specific Integrated Circuit), DSP (Digital
Signal Processor) or FPGA (Field Pro)
grammable Gate Array).

The output method according to the seventh aspect of the present invention is characterized in that a predetermined real impulse constant r (-1 <r <1) and a predetermined real number constant
For C (C ≠ 0), a pseudo-random number sequence of length N (N ≧ 1) is output, comprising a sequence receiving step, a calculating step, and an output step, and configured as follows: .

That is, in the sequence receiving step, an input of a spreading code z [1], z [2],..., Z [L] having a length L (L ≧ 1) is received as a sequence initial value.

On the other hand, in the calculation step, z
From [1], z [2],..., Z [L], a predetermined integer M (1 ≦ M ≦ N, M + N
<L), z ′ [1], z ′ [2],.
Calculate [N].

Further, in the output step, z ′ [1], z ′ [2],
…, Z ′ [N] are output as a pseudo-random number sequence.

In the output method of the present invention, the length L
Can be configured to be an M-sequence, a Gold code, a bulk code, a Walsh-Hadamard orthogonal code, or a chaotic code generated by a Chebyshev polynomial.

Further, in the output method of the present invention, the predetermined actual impulse constant r can be configured so as to satisfy [Equation 8].

The transmitting method according to the eighth aspect of the present invention is configured to include a signal receiving step, a generating step, a spreading step, and a signal transmitting step.

Here, in the signal receiving step, an input of a transmission signal is received.

On the other hand, in the generation step, a pseudo-random number sequence of length N is output and generated by the above output method.

Further, in the spreading step, the transmission signal whose input has been accepted is spectrum-spread using the generated pseudo-random number sequence of length N as a spreading code.

Then, in the signal transmitting step, the signal resulting from the spread spectrum is transmitted.

Further, the transmitting method of the present invention comprises the following steps:
It further includes a parameter transmitting step, and can be configured as follows.

That is, in the selection step, the spreading codes z [1],
Select z [2],…, z [L].

On the other hand, in the parameter transmitting step, the selected spreading codes z [1], z [2],..., Z [L] are transmitted.

Further, in the generation step, the selected spreading codes z [1], z [2],..., Z [L] are received as the sequence initial values.

The transmission method of the present invention further includes a parameter receiving step, and can be configured as follows.

That is, in the parameter receiving step, spread codes z [1], z [2],..., Z [L] are received.

On the other hand, in the generation step, the received spread code
z [1], z [2],..., z [L] are accepted as sequence initial values.

A receiving method according to a ninth aspect of the present invention includes a signal receiving step, a generating step, a despreading step, and an output step, and is configured as follows.

That is, in the signal receiving step, a signal is received.

On the other hand, in the generation step, a pseudo-random number sequence of length N is output by the above output method.

Further, in the despreading step, the received signal is converted into a spreading code using the output pseudo-random number sequence of length N as a spreading code.
The spectrum is despread.

In the output step, a signal resulting from spectrum despreading is output as a transmission signal.

The receiving method according to the present invention further comprises a selecting step,
And a parameter transmitting step, and can be configured as follows.

That is, in the selection step, the spreading codes z [1],
Select z [2],…, z [L].

On the other hand, in the parameter transmitting step, the selected spreading codes z [1], z [2],..., Z [L] are transmitted.

Further, in the generation step, the selected spreading codes z [1], z [2],..., Z [L] are accepted as the sequence initial values.

The receiving method according to the present invention further includes a parameter receiving step, and can be configured as follows.

That is, in the parameter receiving step, spread codes z [1], z [2],..., Z [L] are received.

On the other hand, in the generation step, the received spread code
z [1], z [2],..., z [L] are accepted as sequence initial values.

The filter method for the predetermined real impulse constant r (-1 <r <1) and the predetermined real constant C according to the tenth aspect of the present invention includes an input step, a delay step, and an amplification step. , An addition step, and an output step, and are configured as follows.

That is, in the input step, an input of an input signal having a chip length D is received.

On the other hand, in the delay step, a plurality of signals obtained by delaying an input signal received by 0, D, 2D, 3D,..., (N−1) D are output.

Further, in the amplification step, when the delay time is T, each of the plurality of delayed signals is output by multiplying it by C (−r) ^{1 + T / D.}

In the adding step, the sum of a plurality of amplified and output signals is output.

On the other hand, in the output step, the added and output signals are output.

Further, in the filter method of the present invention, the predetermined real impulse constant r can be configured so as to satisfy [Equation 8].

A program according to an eleventh aspect of the present invention causes a computer to function as the above-described output device or filter device, or causes a computer to execute the above-described output method or filter method.

The program can be recorded on a computer-readable information recording medium (including a compact disk, floppy disk, hard disk, magneto-optical disk, digital video disk, magnetic tape, or semiconductor memory). .

A computer-readable information recording medium according to a twelfth aspect of the present invention is configured to record a pseudo-random number sequence output by the output device or the output method.

The program recorded on the information recording medium of the present invention can be stored in a general-purpose computer having a storage device, a computing device, an output device, a communication device, etc., a mobile phone, a PHS device,
Mobile terminals such as game devices, information processing devices such as parallel computers, DSPs (Digital Signal Processors), FPGAs
(Field Programmable Gate Array), etc., to execute the above-described pseudo-random number sequence output device, transmitting device, receiving device, communication system, filter device, processing performed by the pseudo-random number sequence output method, transmission method , A receiving method, and a filtering method.

Further, independently of these devices, the program itself of the present invention can be distributed and sold, and the information recording medium of the present invention can be distributed and sold via a computer communication network.

[0112]

Embodiments of the present invention will be described below. The embodiments described below are for the purpose of explanation, and do not limit the scope of the present invention. Therefore, those skilled in the art can adopt embodiments in which each of these elements or all elements are replaced with equivalents, but these embodiments are also included in the scope of the present invention. .

(First Embodiment) FIG. 1 is a schematic diagram (data flow diagram) showing a schematic configuration of a pseudo random number sequence output device according to a first embodiment of the present invention. Hereinafter, description will be made with reference to this figure.

Output device 1 for pseudo-random number sequence according to this embodiment
01 outputs a pseudo-random number sequence of length N (N ≧ 1) with respect to a predetermined real impulse constant r (−1 <r <1) and a predetermined real number constant C (C ≠ 0). , Sequence receiving unit 102, and calculating unit 103
And an output unit 104.

That is, sequence receiving section 102 sets spreading codes z [1], z [2],..., Z [L] of length L (L ≧ 1) as sequence initial values.
Accept the input of.

On the other hand, calculation section 103 has received an input.
From z [1], z [2],..., z [L], a predetermined integer M (1 ≦ M ≦ N, M +
N <L), z '[1], z' [2],.
Calculate z '[N].

Further, the output unit 104 outputs z ′ [1], z ′ [2],
…, Z ′ [N] are output as a pseudo-random number sequence.

The calculation in the calculation unit 103 can be realized by a polynomial operation by a computer.
It can also be realized by a combination of an addition / subtraction circuit and a multiplier circuit.
Further, it may be realized by a floating-point operation for which a predetermined accuracy is guaranteed, or by a rational number operation. This will be described later.

Also, the input of the sequence initial value and the integer parameter in the sequence receiving unit 102 and the output unit 104
Output in RAM (Rand
om Access Memory) and CPU (Central Processing Uni)
t; central processing unit), and in the case of an electronic circuit, it can be realized using a latch or the like.

As is apparent from the above recurrence formula, z ′
Since calculations for obtaining [1], z '[2],..., Z' [N] are independent of each other, calculations can be performed in parallel with a maximum degree of parallelism N. In addition, since it is described by a recurrence formula, the calculation can be easily performed by a repetitive operation using a loop.

As the spreading code serving as the initial value of the sequence, an M sequence, a Gold code, a bulk code, a Walsh-Hadamard orthogonal code, a chaotic code generated by a Chebyshev polynomial, or the like can be used. Hereinafter, a chaotic code generated by the Chebyshev polynomial will be described.

FIG. 2 is a graph showing a Chebyshev polynomial. The Chebyshev polynomial can be defined by the addition theorem of a cosine function, such as T (a, cosθ) = cos (aθ), where the integer a is an order. On the other hand, it can be directly expressed by a rational polynomial as follows. T (0, x) = 1 T (1, x) = x T (2, x) = 2x ² -1 T (3, x) = 4x ³ -3x

Each of the Chebyshev polynomials y = T (a, x) is a rational mapping that maps an open interval -1 <x <1 to an open interval -1 <y <1.

In this figure, Chebyshev polynomials of degree 2 to 5 are represented by y = T (2, x), y = T (3, x), y = T (4, x), y =
It is displayed in the form of T (5, x). The horizontal axis is the x axis,
The vertical axis is the y-axis.

The following is conceivable as a chaotic code generated using such a Chebyshev polynomial. The first is the most basic chaotic code, which is calculated by the following recurrence formula. z [i + 1] = T (a, z [i])

The second is an application of this, and the sequence initial values Y ₁ , Y ₂ ,..., Y _s (-1 <Y ₁ <1, -1 <Y ₂ <1,.
<Y _s <1), predetermined integer constants q ₁ , q ₂ ,..., Q _s , predetermined integer parameters p ₁ , p ₂ ,..., P _s (where q ₁ mod p ₁ ≠ 0, q ₂ mod
p ₂ ≠ 0,..., q _s mod p _s ≠ 0) is calculated using the following recurrence formula [Equation 11].

[0127]

[Equation 11]

(Theoretical Background) The fact that the correlation function of the pseudo-random number sequence of length N output when using the chaotic code based on the Chebyshev polynomial becomes the above-mentioned optimal correlation function is based on Lebesgue developed in ergodic theory. Based on the theory of spectrum (Lebesgue Spectrum). This theory is disclosed in the following literature. V. I. Arnold and A. Avez `` Ergodic Problems of Clas
sical Mechanics "(WA Benjamin, New York, 1968)

Hereinafter, the theory of Lebesgue spectrum will be described.

Now, the sequence X ₁ , X ₂ ,... Generated from the dynamic system of X _{n + 1} = F (X _n ) is in the region Q defining the dynamic system.
For the upper limit density distribution function (invariant measure) ρ (x) dx,
It has ergodic properties.

[0131] Then, the inner product on this invariant measure <u, v> = from _{∫ Q u (x) v (} x) ρ (x) dx, is naturally norm operation || · || || v || ² = <v, v> can be considered a Hilbert space L ₂ is defined as.

[0132] According to the above document, in the L ₂ space, there orthonormal basis [number 12] satisfying special properties that depend on the dynamical system is present uniquely. This is called Lebesgue spectrum.

[0133]

(Equation 12)

Here, λ labels each class of the Lebesgue spectrum, and j is a label indicating a function of each class, and corresponds to an infinite number of zero or more integers to be added.

From this definition, the Lebesgue spectrum is:
It can be seen that the system is an orthonormal function system consisting of an infinite number of functions. In particular, the number of possible types of label λ (cardinal of Λ
If ity) is infinite, this Lebesgue spectrum is called an infinite Lebesgue spectrum. Further, the Lebesgue spectrum, not only orthonormal basis, when a complete orthonormal basis in L ₂ space, called the Lebesgue spectrum completely Lebesgue spectrum.

The special property of the Lebesgue spectrum is to satisfy the following.

[0137]

(Equation 13)

That is, if the following function [Equation 14] is given, all other Lebesgue spectrum functions [Equation 15] of class λ repeatedly apply the mapping F (•) defining the dynamical system. Can be obtained.

[0139]

[Equation 14]

[0140]

(Equation 15)

On the assumption that the Lebesgue spectrum forms an orthonormal system, each of these functions [Equation 16]
Is any other function of the same class [Equation 17] and
It is orthogonal to any function [Equation 18] of any other class.

[0142]

(Equation 16)

[0143]

[Equation 17]

[0144]

(Equation 18)

As an ergodic dynamical system having a complete Lebesgue spectrum, there is a Chebyshev chaotic dynamical system given by a second-order or higher Chebyshev polynomial described later.
The Chebyshev chaotic dynamical system is disclosed in the following literature. R. L. Adler, T .; J. Rivlin "Proc. Am. Math. Soc. 1
5 "(1964, p794)

Now, it is assumed that a function B (x) having L ₂ can be expanded by Lebesgue spectrum as shown in [Equation 19].

[0147]

[Equation 19]

In this case, the correlation function [Equation 20] is given by the Lebesgue spectrum expansion coefficient as shown in [Equation 21] from the orthogonality of the Lebesgue spectrum.

[0149]

(Equation 20)

[0150]

(Equation 21)

Note that this correlation function is equal to the time average [Equation 22] due to ergodicity.

[0152]

(Equation 22)

Each X _n is generated by a recurrence equation X _{n + 1} = F (X _n ), and the ergodic equation that the time average is equal to the spatial average is the exceptional initial value X of the measure 0 on Q It holds except for ₁ .

Here, the following is assumed.

[0155]

(Equation 23)

Here, C ₀ is a constant other than 0. this,
By substituting into the above equation giving the correlation function, [Equation 24] is obtained, and the correlation function decreases exponentially as shown in [Equation 25].

[0157]

(Equation 24)

[0158]

(Equation 25)

As described above, regarding the code shift amount l, (-
r) A sequence having a correlation function that exponentially dumps in the form of ^l can be freely created for any r (-1 <r <1).

In particular, as discovered by Mazzini, 15% theoretically in the case of [Equation 10] under the same bit error rate as compared with the case where a random code (including a Gold code and a bulk code) is used as a spreading sequence. You can increase the number of users.

In the spreading sequence in which the variance of the interference noise becomes [Expression 9], the asymptotic behavior of the correlation function may be as shown in [Expression 7]. Therefore, with an ergodic dynamical system having a Lebesgue spectrum and the above B (x) defined by the Lebesgue spectrum function, [Equation 26]
It is enough to prepare a filter designed as follows.

[0162]

(Equation 26)

The problem here is how to construct the ergodic dynamical system F (x) and the Lebesgue spectrum [Equation 12] in an easily realizable form. Hereinafter, a configuration based on Chebyshev mapping will be described.

Now, a Chebyshev polynomial of second or higher order T _p (x)
Consider (p ≧ 2). As described above, this Chebyshev polynomial is defined as T _p (cos θ) = cos ( _p θ), and for each value of p, a distribution function on a closed interval Q = [− 1, 1] [ Under [Equation 27], it is known that they are orthogonal as in [Equation 28].

[0165]

[Equation 27]

[0166]

[Equation 28]

[0167] By these Chebyshev polynomials distribution function, it is possible to constitute a Hilbert space L _2. In this case, the Chebyshev polynomials, the orthogonal basis with integrity in Hilbert space L _2.

In addition, the above-mentioned literature discloses that a dynamical system given by two or more Chebyshev maps has not only an ergodic property but also a stronger mixing property. The ergodic invariant measure in this case is given by the density function ρ (x) that defines the orthogonality described above.

From these properties, a function system φ _{q, j} (x) is now defined as shown in [Equation 29].

[0170]

(Equation 29)

Then, from the orthogonality of the Chebyshev polynomial itself and the relational expression [Equation 30], it can be seen that the functional system φ _{q, j} (x) is a Lebesgue spectrum.

[0172]

[Equation 30]

Therefore, for an integer M (1 ≦ M ≦ N),
If the filter is designed as in [Equation 31], a spreading code for an asynchronous CDMA communication system having the correlation function [Equation 7] can be configured by the explicit solution of the correlation function of Lebesgue spectrum theory described above. This is demonstrated by Mazzini's theory, as described above, to increase the number of users under a certain bit error rate of asynchronous CDMA based on ordinary random codes by 15%. Can be.

[0174]

(Equation 31)

Here, [Equation 32] and [Equation 33] hold, and
[Equation 34] [Equation 3] for any integer m (0 ≦ m ≦ N-1)
5].

[0176]

(Equation 32)

[0177]

[Equation 33]

[0178]

(Equation 34)

[0179]

(Equation 35)

In the case of q = 1, the function B (X) becomes T _q (x) = x, and the equation 36 holds.

[0181]

[Equation 36]

This corresponds to the sequence X _{m + 1} , X _{m + 2} ,..., X _{m + j,.}
X _{m + M-1} and X _{m + M} (1 ≦ j ≦ M) mean an operation of summing the results obtained by multiplying each of them by a constant given to C (−r) ^{M + 1-j} .

This is an FIR filter (Finite Impulse Respo) which is one of the basic filters for digital signal processing.
nse Filter) operation.

Therefore, a high-speed and low-power-consumption device that realizes the calculation according to the present invention by the existing DSP technology using the present FIR filter can be configured.

FIG. 3 is a schematic diagram showing a schematic configuration of the filter configured as described above.

The filter 301 includes various types of spread code sequences X ₁ , X ₂ , and the like, such as Chebyshev-chaotic spread code sequences.
X ₃ ,... Are received at terminal 305.

The received spread code sequence is sequentially delayed and delivered by a delay circuit 302 connected in series. The delay time is a chip length.

The spreading codes appearing successively between the delay circuits 302 are amplified by the amplifier 303. This figure shows the case where the predetermined real number constant C = 1, and the amplification factors are (-r) ¹ , (-r) ² , (-r) ³ , ..., (-r) ^{M, respectively. -1} , (-
r) ^M.

In general, the amplification factor of each of the amplifiers 303 is C
(-r) ¹ , C (-r) ² , C (-r) ³ , ..., C (-r) ^M-1 , C (-r) ^M.

Here, it is optimal to set r to be the actual impulse constant defined by [Equation 8]. However, even if [Equation 8] is not strictly satisfied, as long as −1 <r <1, , Asynchronous CD
It can be used for spreading code generation in MA communication systems.

The signal amplified by the amplifier 303 is
The pseudo random numbers Y ₁ , Y ₂ ,
Y ₃ ,... Are sequentially output.

When a chaotic code generated by using a Chebyshev polynomial is used as the spreading code, the code sequence can be made periodic.

That is, when X _j = X _{j + N + 1} , 2N−
One number X _1, ..., it is not necessary to prepare the X _2N-1. N X
_1, ..., if only X _N, using the periodicity of, all of the m
B (X _m ) can be calculated for (0 ≦ m ≦ N). Therefore,
Further, the calculation time can be reduced.

Similarly, the product of Chebyshev polynomial [Equation 3]
7] also becomes a completely orthogonal basis on the s-dimensional cubic [-1, 1] ^s .

[0195]

(37)

In this embodiment, s predetermined positive integers q ₁ , q
_2, ..., with respect to q _s, respectively _{q 1 mod p 1 ≠ 0,} q 2 mod
_{p 2 ≠ 0 ,, ..., q} s mod p s s integers parameters like ≠ 0 holds p _1, p _2, ..., from the Chebyshev map dynamical systems is determined by p _s, respectively generated For s-dimensional real values x ₁ , x ₂ ,..., x _s , calculate s products [Equation 38].

[0197]

(38)

Then, the calculated values z [1], z [2],.
A pseudo-spread sequence of length N composed of [2N-1] [Equation 39]
Satisfies [Equation 7].

[0199]

[Equation 39]

Therefore, if r is defined as in [Equation 8] and the code length N is made sufficiently long, asynchronous CDMA using a pseudo-random number sequence formed from an s-dimensional direct product chaotic dynamical system as a spreading code is performed.
Is represented by [Equation 9] according to Mazzini's theory, and the number of users can be reliably increased by 15% under the same bit error rate as compared with the existing asynchronous CDMA communication system.

If the relationship (topological isomorphism) of [Expression 40] is satisfied with respect to the Chebyshev map T _p (x) and the diffeomorphism map G (x), this F _p (x) also becomes Chebyshev A chaotic sequence that has a Lebesgue spectrum equivalent to the mapping and that this autocorrelation function dumps like (-r) ^l can be similarly constructed.

[0202]

(Equation 40)

(Experimental Results) In the following, the length of the pseudo-random number sequence
Simulation results of calculating the bit error rate of the present method with respect to the number of users K and the number of taps M while fixing N are shown. The spreading codes to be provided are Chebyshev codes, Gold codes, and general random sequences. In this method, the following parameters were used.・ S = 1. P = 2 (the order of the Chebyshev Generator is equivalent to 2).

FIGS. 4 to 7 are for code length N = 31, FIGS. 8 to 11 are for code length N = 63, and FIGS. 12 to 15 are for N = 127. is there.

From these simulation results, it can be seen that, regardless of the spreading code used, the number of users can be increased by 15% under the same bit error rate as compared with the conventional method. Understand.

Further, it can be seen that the bit error rate for the number of taps M is saturated when M = about 2 to 5. Therefore, it can be understood that the number M of the filter stages may be this number.

In addition, it is understood that the given spreading code is not necessarily a chaotic code using a Chebyshev polynomial.

(Details of Output Method) FIG. 16 shows a process executed by the pseudo random number sequence output device 101, that is,
5 is a flowchart illustrating steps of a pseudo random number sequence output method according to the present invention.

[0209] The pseudo random number sequence output device 101 receives the sequence initial value and the integer parameter (order) (step S3).
01), a pseudo-random number sequence is calculated based on these and the above recurrence formula (step S302), the calculated pseudo-random number sequence is output (step S303), and this processing ends.

As described above, the method of outputting a pseudo-random number sequence according to the present invention can be easily executed by an information processing device such as a general-purpose computer, a parallel computer, a portable terminal, particularly a communication terminal, a game device and the like.

Also, a DSP or FPGA (Field Programm
It is also easy to execute the pseudo-random number sequence output method of the present invention using a digital circuit such as an Able Gate Array.

(Embodiment of Transmitting Apparatus) FIG. 17 is a schematic diagram showing a schematic configuration of the transmitting apparatus of the present invention. Note that the same elements as those in the above-mentioned figures are denoted by the same reference numerals. Hereinafter, description will be made with reference to this figure.

[0213] The transmission device 401 includes a signal reception unit 402,
Sequence output section 403, spreading section 404, signal transmission section 40
5 is provided. The sequence output unit 403 includes the pseudo random number sequence output device 101, and controls this.

[0214] Signal receiving section 402 receives a signal to be transmitted. A typical transmission signal is a voice signal in the case of a mobile phone or PHS. When digital communication is performed, it is an electrical digital signal. In the case of performing optical communication, the optical signal may be converted into an electrical signal and then the electrical signal may be received. In the case where the pseudo random number sequence output device 101 is implemented by an optical computer, the optical signal may be used as it is. Accept.

[0215] Sequence output section 403 causes pseudo-random number sequence output apparatus 101 provided therein to receive a sequence initial value and an integer parameter (order) assigned to transmitting apparatus 401. As described above, the pseudo-random number sequence output device 101 outputs a pseudo-random number sequence.
This pseudo-random number sequence is output.

[0216] Different values can be assigned in advance to the transmission apparatus 401 as the sequence initial value and the integer parameter (degree). Communication terminals that record serial numbers, device numbers, approval numbers, and other numerical values in a ROM (Read Only Memory) have become widespread. Similarly, serial initial values and integer parameters (degrees) are recorded in the ROM in advance. In this case, the transmitting apparatus 401 can always use the same sequence initial value and integer parameter (order). A method of recording a plurality of types of sequence initial values and integer parameters (orders) to be used in the ROM and randomly selecting these for each communication can also be used.

In such an embodiment, the receiving apparatus communicating with the transmitting apparatus 401 needs to know the sequence initial value and the integer parameter (order) recorded in the ROM by some method. In the case where a pair of the receiver and the receiver are provided, an embodiment in which the same sequence initial value and the integer parameter (order) are shared and recorded can be adopted.

When there are a plurality of types of sequence initial values and integer parameters (orders), it is possible to determine which one is used by transmitting apparatus 401 by correlation detection described later. A plurality of sequence initial values may be prepared using a chaotic random number sequence obtained by a recurrence formula based on a Chebyshev polynomial. Further, as will be described later, the transmitting apparatus 401 and the receiving apparatus can safely share the sequence initial value and the integer parameter (degree) using the public key cryptography.

[0219] Spreading section 404 directly spreads the spectrum by sequentially multiplying the transmission signal received by signal receiving section 402 with the elements of the pseudo-random number sequence output from sequence output section 403. Here, assuming that the value of the signal at time t is s (t), “signal s
(t) is sequentially multiplied by the elements of the sequence.

When a sequence element having a length of N is used, the signal s
(t) is multiplied by the elements of the sequence in sequence. ”

[0221] "sequentially multiplying the elements of a sequence in the signal s (t)" from a predetermined time t ₀ when the signal s (t), is discretized in chip length w as obtained the required quality. For example, chip length w
A method of obtaining the value of the signal s (t) for each time, a method of obtaining the average of the value of the signal s (t) during the chip length w, and the like are conceivable. Here, in order to clarify the explanation, the explanation will be made using the former method.

The chip length w needs to be long enough to allow the receiving apparatus to sufficiently decode the information of the transmission signal with necessary quality. However, it is necessary to select an appropriate chip length by a known technique. it can.

Further, if an appropriate chip length w is selected, a signal of sufficient quality can be obtained as viewed from the original transmission signal by sequentially outputting the discretized signal sequence for the chip long time w. it can.

The discretized signal can be represented by the following sequence. s (t ₀ ), s (t ₀ + w), s (t ₀ + 2w), s (t ₀ + 3w), s (t ₀ + 4w), ...

This can be summarized as s _i = s (t ₀ + iw) for an integer i (0 ≦ i).

The method of averaging the values of the signal s (t) during the chip length w can be arranged as follows. s _i = (1 / w) ∫ ₀ ^w s (t ₀ + iu) du

These signal sequences s _i (0 ≦ i) are obtained by discretizing transmission signals with required quality.

[0228] The signal sequence, the signal sequence after the direct sequence spread spectrum _{is, s 0 z '[1]} , s 1 z' [2], ..., s N-1 z '[N], s N z' [1], s _{N + 1} z '
[2], ...

That is, for an integer i (0 ≦ i), s _i × z ′
[(i mod N) +1] is a general term of this sequence. Where x
mod y means the remainder of dividing x by y.

By transmitting the elements of this signal sequence only for the time of the chip length, the received transmission signal of the predetermined time length can be transmitted with the same time length.

FIG. 18 shows a state of the direct spread spectrum processing. Transmission signal 5 received by signal receiving unit 402
01 is repeatedly multiplied by the elements of the pseudo-random number sequence 502 output from the sequence output unit 403,
4 is obtained.

[0232] Signal transmitting section 405 transmits signal 503 output from spreading section 404. The transmission is performed, for example, via an antenna in the case of a mobile phone or PHS, via a wired telephone line or a wired / wireless LAN line in the case of a computer communication network, or via an optical cable.

(Embodiment of Receiving Apparatus) The receiving apparatus of the present invention obtains a pseudo-random number sequence by using the pseudo-random number sequence output device as in the above-described transmitting apparatus, and directly transmits the pseudo-random number sequence for spread spectrum despreading. Used as sign. FIG. 19 is a schematic diagram showing a schematic configuration of the receiving device of the present invention. Hereinafter, description will be made with reference to this figure.

[0234] The receiving apparatus 601 comprises a signal receiving section 602,
A sequence output unit 604 and a despreading unit 605 are provided.

[0235] The signal receiving section 602 is a
1 to receive the signal transmitted. Signal receiving unit 602
Is realized, for example, by an interface to an antenna, a telephone line, an optical cable line, or the like.

The signal received by signal receiving section 602 includes a signal transmitted by transmitting apparatus 401 other than the communication partner and noise. To remove these unnecessary signals,
The same pseudo-random number sequence as the pseudo-random number sequence directly used by the transmitting device 401 of the communication partner for the spread spectrum is used. The sequence output unit 604 outputs the pseudo-random number sequence by causing the output device 101 of the pseudo-random number sequence to receive the sequence initial value and the integer parameter (order) used by the transmitting device 401 of the communication partner. Therefore, the embodiment of sequence output section 604 of receiving apparatus 601 is the same as that of sequence output section 403 of transmitting apparatus 401.

To decode the transmission signal received by the transmitting device 401 of the communication partner, the signal transmitted by the transmitting device 401 of the communication partner is directly subjected to spectrum despreading by sequentially multiplying the reciprocal of the element of the pseudo-random number sequence. I just need.

If synchronization is established, the received signal sequence s ₀ z ′ [1], s ₁ z ′ [2],..., S _N−1 z ′ [N], s _N z '[1], s _{N + 1} z'
By multiplying [2],... By the reciprocals 1 / z '[1], 1 / z' [2],. signal sequence decoded by the required quality _{s 0, s 1, ...,} s N-1, s N, s N + 1, ... are obtained. If these signal trains are sequentially output for each chip long time w, the transmission signal can be restored with the required quality.

For the synchronization, in addition to the correlation detection described later, various methods such as a method of sharing a clock can be considered, and these embodiments are also included in the scope of the present invention.

[0240] As described below, using a public key cryptosystem in which communication is performed between transmitting apparatus 401 and receiving apparatus 601, generating section 611 of the receiving apparatus generates the same sequence initial value and integer parameter (order ) Can be generated.

First, receiving apparatus 601 generates a pair of a public key and a secret key. Next, the receiving device 601 is
01 to the public key. The transmitting apparatus 401 encrypts the sequence initial value and the integer parameter (order) used by itself with the public key and transmits the encrypted initial value and the integer parameter (order) to the receiving apparatus 601. The receiving device 601 decrypts the transmitted cipher with a secret key, and obtains a sequence initial value and an integer parameter (order).

As a technique of such a public key encryption, a chaos encryption disclosed by the inventor of the present invention in Japanese Patent Application No. 11-152563 can be used.

(Other Embodiments of Spreading / Despreading) In addition to the above-described embodiments, the following embodiments can be adopted in the case of spreading / despreading. That is, consider a case where it is desired to transmit the following information data each having a value of +1 or -1. b ₁ , b ₂ , b ₃ , ...

The transmitting apparatus 401 sequentially multiplies this sequence by a pseudo-random number sequence as follows. b ₁ z '[1], b ₁ z' [2], ..., b ₁ z '[N], b ₂ z' [1], b ₂ z '[2], ..., b ₂ z' [N ], B ₃ z '[1], b ₃ z' [2], ..., b ₃ z '[N], ...

[0245] Transmitting apparatus 401 transmits the spread signal.

On the other hand, it is assumed that the signal received by receiving apparatus 601 is as follows. _{s 1, s 2, ...,} s N, s N + 1, s N + 2, ..., s 2N, s 2N + 1, s 2N + 2, ..., s 3N, ...

The receiving apparatus 601 multiplies this by a pseudo-random number sequence in order, and obtains a sum every N units. That is, despreading is performed as follows. e ₁ = s ₁ z '[1] + s ₂ z' [2] + ... + s _N z '[N], e ₂ = s _{N + 1} z' [1] + s _{N + 2} z '[2 ] + ... + s _2N z '[N], e ₃ = s _{2N + 1} z' [1] + s _{2N + 2} z '[2] + ... + s _3N z' [N], ...

The sequence obtained in this way is the restored information data.

[0249] In this method, N times the number of the initial information data b ₁ , b ₂ , b ₃ ,...
Sent from 1. In the receiving device 601, the number of the restored information data e ₁ , e ₂ , e ₃ ,.
1 / N. Therefore, assuming that the chip length of the transmitted and received signal is w, the chip length of the original information data and the restored information data is Nw.

The above calculation corresponds to the inner product. However, since the spreading codes are orthogonal to each other, the amplitude of the transmission signal of another user can be made zero by taking the inner product. Therefore, only necessary signals can be obtained.

(Embodiment of Correlation Detection) Transmission Apparatus 401
In the case where any one of a plurality of pseudo-random number sequences is selected and the spectrum is directly spread, the receiving apparatus 601 can obtain the selected pseudo-random number sequence by correlation detection.
Further, synchronization for direct spectrum despreading can be achieved by correlation detection.

Hereinafter, an embodiment of a receiving apparatus in the case of performing correlation detection will be described with reference to FIG. In FIG. 20, the same elements as those shown in the above-mentioned figures are denoted by the same reference numerals.

The receiving apparatus 601 includes a signal receiving section 602,
In addition to the sequence output unit 604 and the despreading unit 605, the unit includes a generation unit 611 and a correlation detection unit 612.

The generating section 611 outputs a set of a sequence initial value and an integer parameter (degree) selectable by the transmitting apparatus 401. Only one pseudo-random number sequence may be output. in this case,
The correlation detection unit 612 does not need to select any one of a plurality of sets of sequence initial values and integer parameters (orders), and thus functions to synchronize signals.

Sequence output section 604 outputs a pseudo-random number sequence selectable by transmitting apparatus 401 in accordance with the sequence initial value and integer parameter (order) generated by generation section 611.

In correlation detection section 612, sequence output section 604
Attempt correlation detection for each of the pseudo-random number sequences output by. Correlation detection is performed by sequentially multiplying the received signal by "elements" of a pseudo-random number sequence to be examined. Known techniques can be used for the correlation detection.

Since the pseudo-random number sequence used in the present invention has excellent correlation characteristics, when a different pseudo-random number sequence is selected by the receiving apparatus 601, the intensity of the signal after multiplication becomes extremely weak, and the pseudo-random number sequence is used for correlation detection. Fail.

On the other hand, if the same pseudo random number sequence as that of transmitting apparatus 401 is selected and correlation detection is performed, the intensity of the multiplied signal exceeds a predetermined value. Further, it is possible to synchronize the signal by moving the offset of the pseudo random number sequence so as to synchronize with the received signal.

Despreading section 605 sequentially multiplies the signal received by signal receiving section 602 by the “reciprocal number of the element” of the pseudo-random number sequence selected by correlation detecting section 612 and synchronized with the received signal. , Decode the transmission signal.

The received signal is subjected to correlation detection section 61.
2 is different in that the elements are sequentially multiplied by the “element” of the pseudo-random number sequence, whereas the despreading unit 605 is multiplied by the “reciprocal element” of the pseudo-random number sequence in order. In the former, the autocorrelation and cross-correlation are calculated, whereas in the latter, decoding is performed.

(Communication System) The communication system of the present invention can be composed of the above-mentioned transmitting apparatus 401 and the above-mentioned receiving apparatus 601 which receives a signal transmitted by the transmitting apparatus 401 and decodes a transmission signal. If the transmitting device 401 and the receiving device 601 use different pseudo-random number sequences, decoding of the transmission signal fails.

Therefore, even if a plurality of transmitting apparatuses 401 and a plurality of receiving apparatuses 601 are communicating in the same frequency band,
Mutual communication can be performed while maintaining confidentiality and guaranteeing quality according to the number of pairs of communicating parties in use.

In particular, in the pseudo-random number sequence generated according to the present invention, the number of types of codes can be significantly increased as compared with the conventional pseudo-random number sequence. Suitable for communication.

[0264]

As described above, according to the present invention,
Pseudorandom number sequence output device, transmission device, receiving device, communication system, filter device, pseudorandom number sequence output method, transmission method, reception method, filter method, and pseudorandom number sequence suitable for use as a spreading code in an asynchronous CDMA communication system , An information recording medium can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a schematic configuration of a pseudo random number sequence output device of the present invention.

FIG. 2 is a graph showing an outline of Chebyshev mapping.

FIG. 3 is a schematic diagram showing a schematic configuration of an FIR filter usable in the present embodiment.

FIG. 4 is a graph showing a simulation result of a bit error rate according to the present technique.

FIG. 5 is a graph showing a simulation result of a bit error rate according to the present technique.

FIG. 6 is a graph showing a simulation result of a bit error rate according to the present technique.

FIG. 7 is a graph showing a simulation result of a bit error rate according to the present technique.

FIG. 8 is a graph showing a simulation result of a bit error rate according to the present technique.

FIG. 9 is a graph showing a simulation result of a bit error rate according to the present technique.

FIG. 10 is a graph showing a simulation result of a bit error rate according to the present technique.

FIG. 11 is a graph showing a simulation result of a bit error rate according to the present technique.

FIG. 12 is a graph showing a simulation result of a bit error rate according to the present technique.

FIG. 13 is a graph showing a simulation result of a bit error rate according to the present technique.

FIG. 14 is a graph showing a simulation result of a bit error rate according to the present technique.

FIG. 15 is a graph showing a simulation result of a bit error rate according to the present technique.

FIG. 16 is a flowchart showing steps of a pseudo random number sequence output method according to the present invention.

FIG. 17 is a schematic diagram illustrating a schematic configuration of a transmission device of the present invention.

FIG. 18 is an explanatory diagram showing a state of direct spectrum spreading.

FIG. 19 is a schematic diagram showing a schematic configuration of a receiving device of the present invention.

FIG. 20 is a schematic diagram illustrating an embodiment of a receiving apparatus when performing correlation detection.

[Explanation of symbols]

 Reference Signs List 101 pseudo random number sequence output device 102 sequence receiving unit 103 calculating unit 104 output unit 301 FIR filter 302 delay circuit 303 amplifier 304 adder 305 terminal 401 transmitting device 402 signal receiving unit 403 sequence output unit 404 spreading unit 405 signal transmitting unit 501 transmission Signal 502 Pseudo random number sequence 503 Output signal 601 Receiving device 602 Signal receiving unit 604 Sequence output unit 605 Despreading unit 611 Generating unit 612 Correlation detecting unit

 ──────────────────────────────────────────────────続 き Continuing from the front page (71) Applicant 501121439 Akihiro Yamaguchi 3-30-1 Washirohigashi, Higashi-ku, Fukuoka City, Fukuoka Prefecture Fukuoka Institute of Technology Faculty of Information Engineering Department of Information Systems Engineering (72) Inventor Ken Umeno Nukii, Koganei-shi, Tokyo 4-2-1 Kitamachi Inside Communications Research Laboratory, Ministry of Internal Affairs and Communications (72) Inventor Akihiro Yamaguchi 3-30-1 Washirohigashi, Higashi-ku, Fukuoka City, Fukuoka Prefecture F-term Institute of Information Engineering, Information Systems Engineering F-term (reference) 5J104 FA08 NA04 5K022 EE02 EE21 EE33

Claims (32)

[Claims] A predetermined real impulse constant r (-1 <r <1);
An output device that outputs a pseudo-random number sequence having a length N (N ≧ 1) for a predetermined real constant C (C ≠ 0), and having a length L (L ≧ 1) as a sequence initial value. Spreading codes z [1], z [2],
, Z [L], and a predetermined integer M (1 ≦ M ≦ N, M) from z [1], z [2],. + N <L) , Z '[N], and z' [1], z '[2], ..., z' [N] An output device comprising: an output unit that outputs a random number sequence. 2. The method according to claim 1, wherein the spreading code of length L is an M-sequence, a Gold code, a bulk code, a Walsh-Hadamard orthogonal code, or a chaotic code generated by a Chebyshev polynomial. Output device as described. 3. The predetermined real impulse constant r is given by: The output device according to claim 1, wherein the output device satisfies the following. 4. A signal receiving unit for receiving an input of a transmission signal, an output device for outputting a pseudo-random number sequence having a length of N according to claim 1, and a transmission receiving said input. A signal, comprising: a spreading unit that spreads a spectrum using the output pseudo-random number sequence of length N as a spreading code; and a signal transmitting unit that transmits a signal resulting from the spread spectrum. apparatus. 5. A selecting unit for selecting a spreading code z [1], z [2],..., Z [L], and a selected spreading code z [1], z [2],. L], and a parameter transmission unit for transmitting the selected spreading code z [1], z [2],
.., Z [L] is received as a sequence initial value. 6. A parameter receiving unit for receiving a spreading code z [1], z [2],..., Z [L], wherein the output device receives the received spreading code z [1], z [L]. [2],
.., Z [L] is received as a sequence initial value. 7. A signal receiving unit for receiving a signal, an output device for outputting a pseudo-random number sequence having a length of N according to claim 1, and outputting the received signal to the output unit. A pseudo-random number sequence having the length N as a spreading code, a despreading unit that performs spectrum despreading, and an output unit that outputs a signal resulting from the spectrum despreading as a transmission signal. apparatus. 8. A selecting unit for selecting a spreading code z [1], z [2],..., Z [L], and a selected spreading code z [1], z [2],. L], and a parameter transmission unit for transmitting the selected spreading code z [1], z [2],
.., Z [L] is received as a sequence initial value. 9. A system further comprising: a parameter receiving unit that receives a spreading code z [1], z [2],..., Z [L], wherein the output device receives the received spreading code z [1], z [2],
.., Z [L] is received as a sequence initial value. 10. A transmitting device according to claim 5, and a receiving device according to claim 9, wherein the receiving device transmits the spreading code transmitted from the transmitting device.
, z [L], and the receiving device receives a signal transmitted from the transmitting device. 11. A transmitting device according to claim 6, comprising: a receiving device according to claim 8, wherein the transmitting device transmits a spread code transmitted from the receiving device.
, z [L], and the receiving device receives a signal transmitted from the transmitting device. 12. A predetermined real impulse constant r (-1 <r <1)
And a predetermined real constant C (C ≠ 0), and an input terminal for receiving an input of an input signal having a chip length D; and
A delay unit that outputs a plurality of signals delayed by 2D, 3D,..., (N−1) D, and, when the delay time is T, (-r) an amplification unit for multiplying and outputting ^{1 + T / D;} an addition unit for outputting a sum of the amplified and output signals; and an output terminal for outputting the added and output signal And a filter device comprising: 13. The predetermined real impulse constant r is given by: The filter device according to claim 12, wherein: 14. An ASIC (Application Specific Int) comprising: a delay unit, an amplification unit, and an addition unit of the filter device.
egrated Circuit), DSP (Digital Signal Processo)
r) or FPGA (Field Programmable Gate A)
(rray).
Or a filter device according to item 13. 15. A predetermined actual impulse constant r (-1 <r <1)
And a predetermined real constant C (C ≠ 0), the length N (N ≧
An output method of outputting the pseudo-random number sequence of 1), wherein a spreading code z [1], z [2], and a length L (L ≧ 1) is used as a sequence initial value.
, Z [L], and a predetermined integer M (1 ≦ M ≦ N, M) from z [1], z [2],. + N <L) , Z '[N], and z' [1], z '[2], ..., z' [N] are simulated. An output step of outputting as a random number sequence. 16. The spreading code of length L is an M-sequence, a Gold code, a bulk code, a Walsh-Hadamard orthogonal code,
The output method according to claim 15, wherein the output method is a chaotic code generated by a Chebyshev polynomial. 17. The predetermined real impulse constant r is given by: The output method according to claim 15, wherein the following method is satisfied. 18. A signal receiving step of receiving an input of a transmission signal; and a generating step of outputting and generating a pseudo-random number sequence of length N by the output method according to claim 15. A spreading step of spreading the spectrum of the received transmission signal using the generated pseudo-random number sequence of length N as a spreading code, and a signal transmitting step of transmitting a signal resulting from the spectrum spreading. A transmission method characterized by the above-mentioned. 19. A selecting step of selecting a spreading code z [1], z [2],..., Z [L], and the selected spreading code z [1], z [2],. L] for transmitting the selected spreading code z [1], z
19. The transmission method according to claim 18, wherein [2],..., Z [L] are received as sequence initial values. 20. The apparatus further comprising: a parameter receiving step of receiving a spreading code z [1], z [2],..., Z [L].
19. The transmission method according to claim 18, wherein [2],..., Z [L] are received as sequence initial values. 21. A signal receiving step of receiving a signal, a generating step of outputting a pseudo-random number sequence of length N by the output method according to any one of claims 15 to 17, A despreading step of performing spectrum despreading using the generated pseudo-random number sequence of length N as a spreading code; andan output step of outputting a signal resulting from the spectrum despreading as a transmission signal. And the receiving method. 22. A selecting step of selecting a spreading code z [1], z [2],..., Z [L], and selecting the selected spreading code z [1], z [2],. L] for transmitting the selected spread code z [1], z
22. The receiving method according to claim 21, wherein [2],..., Z [L] are received as a sequence initial value. 23. The apparatus further comprising a parameter receiving step of receiving a spreading code z [1], z [2],..., Z [L].
22. The receiving method according to claim 21, wherein [2],..., Z [L] are received as a sequence initial value. 24. A predetermined actual impulse constant r (-1 <r <1)
And a filter method for a predetermined real constant C (C ≠ 0), wherein: an input step of receiving an input of an input signal having a chip length D; and 0, D,
A delay step of outputting a plurality of signals delayed by 2D, 3D,..., (N−1) D, and, when the delay time is T, (-r) an amplification step of multiplying and outputting ^{1 + T / D,} an addition step of outputting a sum of the amplified and output signals, and an output step of outputting the added and output signal And a filter method comprising: 25. The predetermined real impulse constant r is: The filter method according to claim 24, wherein the following condition is satisfied. 26. A program for causing a computer to function as the output device according to claim 1. Description: 27. A computer according to claim 12,
A program for causing a computer to function as the filter device according to item 1. 28. A program for causing a computer to execute the output method according to any one of claims 15 to 17. 29. The computer according to claim 24 or 25,
A program for causing a computer to execute the filter method according to the above. 30. A computer-readable information recording medium (compact disk, floppy (registered trademark) disk, hard disk, magneto-optical disk), wherein the program according to any one of claims 26 to 29 is recorded. , A digital video disk, a magnetic tape, or a semiconductor memory.) 31. A computer-readable information recording medium (compact disk, floppy disk, hard disk), wherein a pseudo-random number sequence output by the output device according to any one of claims 1 to 3 is recorded. , A magneto-optical disk, a digital video disk, a magnetic tape, or a semiconductor memory.) 32. A computer-readable information recording medium (compact disk, floppy disk, hard disk), wherein a pseudo-random number sequence output by the output method according to any one of claims 15 to 17 is recorded. , Magneto-optical disk, digital video disk,
Includes magnetic tape or semiconductor memory. ).