JP2986260B2 - Spread spectrum two-way communication device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spread-spectrum two-way communication device, and more particularly to a leak from a transmission system to a reception system when transmitting / receiving data in a spread spectrum communication (hereinafter, referred to as SS communication) system. And so-called perspective problems.

[0002]

2. Description of the Related Art In an SS communication system, an information signal is spread-modulated with a pseudo-noise code (hereinafter, referred to as a PN code) having a spectrum width sufficiently larger than that of the information signal, and is transmitted. And selectively receive only the information signal by spread demodulation (for example, magazine "Electronics", May 1979, pp. 33-44). In the SS communication system, when the signal is spread and demodulated with a specific PN code, only the intended signal can be selectively received, so that excellent confidentiality and noise resistance can be obtained.

[0003]

However, when performing a two-way communication by the SS communication method, when a single communication device includes a transmission system and a reception system, a part of the transmission output leaks to the reception system. In addition, there is a possibility that the quality of reception may be deteriorated.

[0004] Even if a PN code having a small correlation is used, its correlation value is usually at least 1 / N.
(N is the code length of the PN code) or -1 / N. For example, in the case of a 7-bit PN code, the correlation value is 1/7 or-／.
I can only do that. For this reason, in a two-way communication device in which the transmission unit and the reception unit are integrated, the transmission level is considerably higher than the reception level, so that the influence of the leakage from the transmission unit to the reception unit can be ignored. Because it is gone.

Therefore, the present invention has been made to solve the above-mentioned problems, and an object of the present invention is to make it possible to transmit a signal from a transmitting unit to a receiving unit even if the transmitting unit and the receiving unit are integrated. It is an object of the present invention to provide a spread spectrum two-way communication device capable of performing high-quality communication by eliminating interference.

[0006]

According to the present invention, in order to achieve the above object, a predetermined information signal to be transmitted is converted into a PN code serving as a predetermined reference and a P / N code obtained by inverting the PN code serving as the reference.
A transmission unit that transmits the spread modulation by combining the PN code generated by connecting the N codes, a reception signal received and used in spread modulation of transmitting the reception signal <br/> issue of its single and receiving unit, the extracting an information signal to be received by spread demodulation with a predetermined PN code and synthetic PN code generated by connecting its PN code
It is characterized in that chromatic-flight communication.

[0007]

In the above configuration, the information signal transmitted from the transmitting unit in a single communication device is generated by connecting a predetermined PN code and a PN code obtained by inverting the PN code. It is spread-modulated with the combined PN code and transmitted. On the other hand ,
Information signal received by the reception unit in a single communication flight is obtained by spread demodulation PN code used at the time of the information signal is spread-modulated by two produced connected to the synthetic PN code .

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram of an embodiment of the present invention, in which A is a transmitter / receiver as a master unit (hereinafter referred to as master unit A), and this master unit A has a plurality of transmitters / receivers as slave units. Receivers B, C and i (hereinafter referred to as slave unit B, slave unit C and slave unit i.
Here, only three slave units are shown to simplify the drawing. ) Are provided as a pair. Information signal A is transmitted from master unit A to slave units B, C... I, and information signals B, C are assigned to master unit A from slave units B, C. .. I are transmitted.

The transmitting section a of the master unit A is composed of a spread modulation circuit 1 and a transmission / reception circuit 2. In the spread modulation circuit 1, the information signal A to be transmitted to each of the slave units B, C... I is subjected to spread modulation processing using a predetermined PN code (PN _A ). This PN code (PN _A ) is used as a reference PN code (P
N ₁ ) and a PN code (* PN ₁ ) obtained by inverting the PN code (PN ₁ ) (* means inversion. The same applies hereinafter. In the drawings and formulas, a bar (-) is added. A composite PN code (PN ₁ + *) generated by connecting
PN ₁ ). Then, the transmission / reception circuit 2 transmits the spread-modulated signal to each of the slave units B, C.
To be sent to.

The transmission units a, a,... Of each of the slave units B, C,. However, these child machine B, C ... transmitting portion a of i, a ... synthetic PN code used in the spreading modulation circuit 1 of, the PN code (PN ₁₎ of the above criteria or any other PN code (PN _{2 to} PN
_i ) are connected to each other to generate a PN code (PN _{B to} PN).
_i ). That is, the combined PN code (P
N _B) was based on the above criteria PN code (PN ₁₎ (P
N ₁ + PN ₁ ), the composite code (PN _C ) of the slave C is (PN ₂ + PN ₂ ), and the composite code (P
N _i ) is PN _i + PN _i ).

The receiving units of the master unit A include receiving units b _{1 to} b _{n including} a number of spreading demodulation circuits 4 corresponding to the respective slave units so that the information signals from the slave units B, C... Is provided. The receiving section b ₁ corresponds to the slave unit B, and spreads the signal received via the antenna 3 and the transmission / reception circuit 2 by spreading and demodulating the signal with the synthetic PN code (PN _B ) for transmission of the slave unit B. It has a demodulation circuit 4. Hereinafter, likewise, the receiving unit b ₂ is compatible with the slave unit C, the spread demodulation circuit 4
Is a combined PN code (PN _C ), and
The receiving unit b _n corresponds to the slave unit i, and the PN code used in the spread demodulation circuit 4 is (PN _i ).

The receiving unit b of each of the slave units B, C... I has the same configuration as the receiving unit b of the master unit A. The composite PN code used in the spread demodulation circuit 4 of the receiving section b is a composite PN code (PN _A ) for transmission of the master unit A.

Next, in the apparatus of the present embodiment configured as described above, the signal from the transmitting section a is transmitted to the receiving sections b, b _{1 to} b
_Describe why _n is not affected.

Now, the reference PN code (PN ₁ ) is set to PN
_{If 1} = (a ₀ , a ₁ , a ₂ ,..., _An-1 ), the inverted reference PN code (* PN ₁ ) becomes * PN ₁ = (− a
₀ , −a ₁ , −a ₂ ,..., −a _n−1 ).
The PN code (PN _A ) generated by connection is represented by the following equation (1).
It is represented as Similarly, the composite PN code (P
N _B , _P N _C ) are also represented as in Equations 2 and 3, respectively.

[0015]

(Equation 1)

[0016]

(Equation 2)

[0017]

(Equation 3) Here, PN codes PN _A and PN _B and their respective correlations R _PAPB of PN _A and PN _C, R _PAPC is expressed as Expression 4 and Expression 5.

[0018]

(Equation 4)

[0019]

(Equation 5) These equations 4 and 5 can be rewritten as equations 6 and 7 below.

[0020]

(Equation 6)

[0021]

(Equation 7) In the above equation (6), considering the case of 0 chip shift,
^{_{P PAPB = (a 0 2 +}} a 1 2 + ... + a n-1 2) + ((- a
_{^{0 2) + (- a 1}} 2) + ... + (- a n-1 2)) = 0 , and the it can be seen that the cross-correlation value is 0. Also, any j
Considering the case of chip shift, R _PAPB = (a ₀ ×
a _nj + ... + a _j × a ₀ + ... + a _n-1 × a _nj-1 ) +
((−a _j × a ₀ ) +... + (− _An-1 × _anj-1 )) =
It can be seen that the cross-correlation value becomes 0 as in the case of the 0-chip shift.

Therefore, it can be seen that the cross-correlation value is 0 even at all chip shifts. This allows
It can be seen that not occur near-far problem between the transmitting portion a of the master unit A and the reception section b _1.

Next, when the above _equation (7) is similarly considered, at the time of a 0-chip shift, R _PAPC = (a ₀ × b ₀ + a
₁ × b ₁ +... + A _n-1 × b _n-1 ) + ((− a ₀ × b ₀ )
+ (− A ₁ × b ₁ ) +... + (− A _n−1 × b _n−1 )) = 0
It can be seen that the cross-correlation value becomes 0. Also, considering a case where an arbitrary j-chip shift is performed, R _PAPC =
(A ₀ × b _nj +... + A _j × b ₀ +... + A _n-1 × b
_{nj-1) + ((-} a 0 × b nj) + ... + (- a j ×
b ₀ ) +... + (− a _n-1 × b _nj-1 )) = 0 and 0
The cross-correlation value is 0 as in the case of the chip shift.

Accordingly, the value becomes 0 even in all chip shifts, and it can be understood that the distance problem does not occur between the transmitting unit a and the receiving unit b ₂ of the master unit A.

Further, the correlation R _PAPI the PN code PN _A and PN _i is above the PN code PN _B or PN _C and PN _A
It can be easily inferred from the cross-correlation with that it becomes zero. Therefore, it is possible to maintain good communication quality without near-far problem occurs between the transmission unit a and the receiving portion b ₁ ~b _n of the master unit A.

Further, each child device B, synthesized PN code _{(PN B, PN C ... PN} i) used in the transmission part a of C ... i The synthetic PN code used by the receiver b (PN _A), As described above, since the cross-correlation value is 0, the distance problem does not occur similarly to the master unit A.

[0027]

In the present invention equipment according to the present invention, a single communication-flight
The provided transmission unit, predetermined information signal to be transmit,
A predetermined reference becomes PN code synthetic PN code generated by connecting the PN code of the PN code is inverted to be the reference, and sent to spreading modulation, et provided on the single communication-flight
In the receiver to the received signal received, a predetermined PN code used in the spread modulation of transmitting the reception signal of that the P
Since there was N code I and you to extract information signals to be received by spread demodulation in the generated synthesized PN code by connecting Unishi, without causing a near-far problem by cross-correlation value becomes 0, the high-quality Two-way communication can be performed.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an apparatus according to an embodiment of the present invention.

[Explanation of symbols]

1 spreading modulation circuit 2 receiving circuit 3 antenna 4 spread demodulation circuit a transmission section b, b ₁ ~b _n receiver A transmitter and receiver (base unit) B to I transmitter and receiver (handset)

Continuation of the front page (56) References JP-A-59-104841 (JP, A) JP-A-60-24742 (JP, A) JP-A-4-347942 (JP, A) "Latest spread spectrum communication method" , R.A. C. By Dixon, translated by Tateno et al., Published by S53.11 Jatec Publishing, p. 204-205 "Non-linear Synthetic Code Sequence for High-speed Synchronization Acquisition", Tachikawa et al., 1987.3.35, IEICE Technical Committee on Spread Spectrum Communication (SS87-7) (58). ⁶ , DB name) H04J 13/00

Claims (1)

(57) [Claims] A predetermined information signal to be transmitted is spread by a synthetic pseudo-noise code generated by connecting a pseudo-noise code serving as a predetermined reference and a pseudo-noise code obtained by inverting the pseudo-noise code serving as the reference. a transmission unit that transmits modulated and the received signal received and generated by connecting a predetermined pseudo-noise code and its pseudo-noise code used in the spread modulation of transmitting the reception signal in its synthesis spread spectrum two-way communication device to a receiving unit for extracting an information signal to be received by spread demodulation with the pseudo-noise code, the characterized in that perforated to a single communication machine.