JP2002135229A - Radio transmission station and radio receiving station for spread spectrum radio communication - Google Patents

Abstract

PROBLEM TO BE SOLVED: To apply spread spectrum to a plurality of information signals, according to required process gains for them and transmit resulting signals as radio signals in the same frequency band. SOLUTION: In a radio transmitting station 1A, a signal divider circuit 1-2 divides an information signal 1-1 to be transmitted into n (n>=2) information signals, having transmission rates V1, V2,..., Vn, spread spectrum circuits 1-3-1 to 1-3-n multiply the divided information signals by mutual different n spread codes having spread ratios K1, K2,..., Kn satisfying the condition that V1.K1=V2.K2=..., = Vn.Kn, a synthesizer circuit 1-4 synthesizes the n spread spectrum signals and a transmitter 1-5 transmits the composited signal as a radio signal in the same frequency band.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio transmitting station and a radio receiving station for spread spectrum radio communication using a plurality of spread codes.

[0002]

2. Description of the Related Art In wireless communication, there is spread spectrum communication as a communication method excellent in interference resistance, and a method of performing spread spectrum using a plurality of spreading codes as a method of increasing an information transmission speed while keeping a processing gain constant. Was published in
3-283246. FIG. 6 is a diagram illustrating a conventional spread spectrum communication method using a plurality of spread codes. In the figure, 6A is a wireless transmitting station, and 6B is a wireless receiving station. First, the configuration of the wireless transmission station will be described. 6-1 is an information signal to be transmitted, 6-2 is a serial / parallel conversion circuit, 6-3-1 to 6-3-n are spectrum spread circuits, and 6-4. Is a combining circuit, 6-5 is a transmitter, and 6-6 is a transmitting antenna. Next, the configuration of the wireless receiving station 6B will be described. 6-7 is a receiving antenna, 6-8 is a receiver, and 6-9-
1-6-9-n are spectrum despreading circuits, 6-10-
1-6-10-n is a demodulation circuit, 6-11 is a parallel / serial conversion circuit, and 6-12 is a demodulated signal.

Next, the principle of the spectrum radio communication system will be described. In the radio transmitting station 6A, the information signal 6-
1 is inputted to the serial / parallel conversion circuit 6-2, each identical having the amount of information and the n pieces of parallel signals S ₁ to S _n having a transmission speed of 1 / n of the original signal 6-1 Is converted. This direct /
N output signals S ₁ to S _n of the parallel converter 6-2, respectively, are input to the spectrum spreading circuit 6-3-1～6-3-n, each different spreading code is multiplied, spread spectrum It is converted into n signals SS ₁ ~ SS _n which made the the. The n spread-spectrum signals SS _{1 to} SS _n are synthesized by the synthesizing circuit 6-4 and then input to the transmitter 6-5, where the antenna 6-6 is transmitted. Sent via

In the radio receiving station 6B, a radio signal is received by a receiver 6-8 via a receiving antenna 6-7, and the received signal is divided into n number of spectrum despreading circuits 6-9-1 to 6-9-1.
6-9-n. The spectrum despreading circuits 6-9-1 to 6-9-n use the spread spectrum circuits 6-3-1 to 6-3-n of the radio transmitting station 6A.
Are despread using the same spreading code as used in (1), and the resulting n output signals are demodulated by demodulation circuits 6-10-1 to 6-10-n, respectively. And n demodulation circuits 6-10-1 to 6-6
The output signal of -10-n is input to the parallel / serial conversion circuit 6-11.
In the reverse procedure performed by the parallel conversion circuit 6-2, n parallel signals are combined into a serial signal and output as a demodulated signal 6-12.

FIG. 7 is a diagram showing an example of a spectrum according to the prior art. In the figure, (a) shows the spectrum of the input signal S ₁ to S _n of the spectrum spreading circuit 6-3-1~6-3-n, (b) is a spread spectrum circuit 6-3-1～
The output signal SS ₁ ~SS _n of the spectrum of 6-3-n,
(C) is the spectrum of the output signal of the synthesis circuit 6-4. Here, the n signals subjected to the serial / parallel conversion have the same frequency bandwidth before the spread spectrum and the same frequency bandwidth after the spread spectrum, and therefore gain obtained by performing the spread spectrum, That is, the processing gain is also equal.

[0006]

In the spread spectrum wireless communication system, in order to perform high quality communication excellent in bit error rate, symbol error rate, frame error rate, etc., an information signal to be transmitted must be transmitted. It is necessary to perform spread spectrum processing with the highest processing gain. However, there is a limit to the usable frequency bandwidth, and there is a limit to increasing the processing gain of spread spectrum to improve communication quality.

On the other hand, the required quality including the bit error rate, symbol error rate, frame error rate and the like often differs depending on the type of information signal to be transmitted. In such a case, ignoring the difference in required quality of each information signal and uniformly applying the spread spectrum of the same processing gain, the processing gain is insufficient for a signal of high required quality,
For signals with low required quality, a situation occurs where the processing gain is excessive.

The present invention has been made in view of the circumstances described above, and has as its object to provide a spread spectrum wireless communication system for transmitting a plurality of information signals in a form suitable for each required quality.

[0009]

In order to solve the above-mentioned problems, according to the present invention, a spread spectrum is applied to a plurality of information signals at a radio transmitting station with a processing gain corresponding to each required quality.

That is, in the wireless transmission station for spread spectrum wireless communication according to claim 1, the transmission rate is a low transmission rate for an information signal having a high required quality and a high transmission rate for an information signal having a low required quality. _1, V _2, ..., V
_n (n is an integer of 2 or more) n information signals
_{V 1 · K 1 = V 2} · K 2 = ...... = V n · K n spreading factor K ₁ which satisfies the condition that, K _2, ..., multiplying each respective spreading codes each having K _n (≠ 1) As a result, n spread-spectrum signals (SS _{1 to} SS _n ) are generated, and these spread-spectrum signals are combined and transmitted as radio signals in the same frequency band.

Further, in the radio receiving station for spread spectrum wireless communication according to the second aspect, the transmission rate is a low transmission rate for an information signal having a high required quality and a high transmission rate for an information signal having a low required quality. _1, V _2, ..., V
_n (n is an integer of 2 or more) n information signals
_{V 1 · K 1 = V 2} · K 2 = ...... = V n · K n spreading factor K ₁ which satisfies the condition that, K _2, ..., multiplying each respective spreading codes each having K _n (≠ 1) Thus, n spread-spectrum signals (SS _{1 to} SS _n ) are generated, and these spread-spectrum signals are combined and transmitted from a radio transmitting station transmitting the same frequency band radio signal. Receiving the wireless signal, for the received wireless signal,
Each of the plurality of spread codes is subjected to spectrum despreading, and the results of these spectrum despreads are demodulated.

Further, in the radio transmission station for spread spectrum radio communication according to claim 3, the transmission rate of n information signals (n is an integer of 2 or more) is set to a low transmission rate for an information signal of high required quality. , V _1, V ₂ is a high transmission rate with low required quality information signal, ..., is converted to V _n, with respect to the converted n pieces of information signals of the transmission rate, V _{1
· K 1 = V 2 · K} 2 = ...... = V n · K n becomes spreading factor K ₁ which satisfies the condition, K _2, ..., by multiplying each of the respective spreading codes each having K _n (≠ 1) Each of n spread-spectrum signals (SS _{1 to} SS _n ) is generated, and these spread-spectrum signals are combined and transmitted as a radio signal in the same frequency band.

In the radio receiving station for spread spectrum radio communication according to the present invention, the transmission rate of n information signals (n is an integer of 2 or more) is set to a low transmission rate for an information signal of high required quality. , V _1, V ₂ is a high transmission rate with low required quality information signal, ..., is converted to V _n, with respect to the converted n pieces of information signals of the transmission rate, V _{1
· K 1 = V 2 · K} 2 = ...... = V n · K n becomes spreading factor K ₁ which satisfies the condition, K _2, ..., by multiplying each of the respective spreading codes each having K _n (≠ 1) Each of the n spread-spectrum signals (SS _{1 to} SS _n ) is generated, the spread-spectrum signals are combined, and the signals are transmitted from a radio transmitting station that transmits the same as a radio signal in the same frequency band. A signal is received, and the received radio signal is subjected to spectrum despreading using each of the plurality of spread codes, and the results of these spectrum despreads are demodulated.

Further, according to claim 5, there is no spread spectrum.
In the line communication radio transmitting station, an information signal to be transmitted is
Transmission rate is low for high quality information signals
In the case of information signals with low required quality,
V₁, V_Two, ..., V_nN (n is an integer of 2 or more)
Information signal, and each divided information signal is
And n different types of spreading codes,₁・
K₁= V_Two・ K_Two= …… = V _n・ K_nExpansion that satisfies certain conditions
Percentage K₁, K_Two, ..., K_nEach spreading code having (≠ 1)
Spread spectrum by multiplying
n signals (SS₁~ SS_n) And generate these
The n spread-spectrum signals are synthesized, and
Transmit the generated signal as a radio signal in the same frequency band.
You.

Further, according to claim 6, there is no spread spectrum.
In the line communication radio receiving station, the information signal to be transmitted is
Transmission rate is low for high quality information signals
In the case of information signals with low required quality,
V₁, V_Two, ..., V_nN (n is an integer of 2 or more)
Information signal, and each divided information signal is
And n different types of spreading codes,₁・
K₁= V_Two・ K_Two= …… = V _n・ K_nExpansion that satisfies certain conditions
Percentage K₁, K_Two, ..., K_nEach spreading code having (≠ 1)
Spread spectrum by multiplying
n signals (SS₁~ SS_n) And generate these
The n spread-spectrum signals are synthesized, and
Transmit the generated signal as a radio signal in the same frequency band
Receiving the radio signal transmitted from the radio transmitting station,
With respect to the obtained radio signal,
Each of them is subjected to spectrum despreading, and these spectrums are
Demodulate the n signals obtained as a result of despreading,
The obtained n signals are then forwarded at the radio transmitting station.
Reverse procedure to the procedure of dividing the information signal into n information signals
Synthesized according to

According to the radio transmission station for spread spectrum radio communication according to the first aspect and the radio reception station for spread spectrum radio communication according to the second aspect, the information signal supplied to the radio transmission station at a low transmission rate has a high spread. Spread spectrum is performed at a rate, and the information signal supplied to the radio transmitting station at a high transmission rate is spread at a low spread rate. According to this spread spectrum wireless communication system, a processing gain proportional to the spreading factor applied to each information signal can be obtained. Between the transmission speed V ₁ ~V _n and spreading factor K ₁ ~K _n applied to each information signal of each information signal V ₁ · K ₁ =
V ₂ · K ₂ = ... = the relationship that V _n · K _n holds can transmit respective signals subjected to the spread spectrum in the same frequency band.

According to the radio transmission station for spread spectrum radio communication according to the third aspect and the radio reception station for spread spectrum radio communication according to the fourth aspect, the n information signals supplied to the radio transmission station are transmitted by the transmission means. Each speed is converted to a predetermined transmission speed, and each information signal is subjected to spectrum spreading at a spreading factor inversely proportional to each transmission speed. According to this spread spectrum wireless communication system, a processing gain proportional to the spreading factor applied to each information signal can be obtained. Between the transmission speed V ₁ ~V _n and spreading factor K ₁ ~K _n applied to each information signal of each information signal _{V 1 · K 1 = V 2} · K 2 =
.. = V _n · K _n holds, so that the spread spectrum signals can be transmitted in the same frequency band.

[0018] A spread spectrum wireless communication according to claim 5.
Wireless transmission station and no spread spectrum according to claim 6
According to the line communication radio receiving station,
Each information signal has a predetermined transmission speed V₁~ V_nN
Each information signal is divided into information signals, and each divided
Spread spectrum is performed with a spreading factor inversely proportional to the transmission speed.
You. According to this spread spectrum wireless communication system,
Processing rate in proportion to the spreading factor applied to each
Gain is obtained. Also, the transmission speed V of each information signal ₁~ V_nWhen
Spreading factor K applied to each information signal₁~ K_nV between₁
・ K₁= V_Two・ K_Two= ... = V_n・ K_nHolds
Therefore, spread-spread each signal at the same frequency.
Can be sent in a band.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. (1) Configuration of Embodiment FIG. 1 is a diagram showing a configuration of a specific embodiment of the present invention.
In the figure, 1A is a wireless transmitting station, and 1B is a wireless receiving station. In the wireless transmission station 1A, 1-1 is an information signal to be transmitted, 1-2 is a signal division circuit, and 1-3-1 to 1-3
n is a spread spectrum circuit, 1-4 is a synthesis circuit, 1-5
Is a transmitter, and 1-6 is a transmitting antenna. In the radio receiving station 1B, 1-7 is a receiving antenna, 1-8 is a receiver, 1-9-1 to 1-9-n are spectrum despreading circuits, and 1-10-1 to 1-10-n Is a demodulation circuit, 1-11
Is a signal synthesis circuit, and 1-12 is a demodulated signal.

<Configuration Example of Spread Spectrum Circuit> FIG. 2 shows a spread spectrum circuit 1-3-1 to -1 in this embodiment.
-3-n shows a specific configuration example. In the figure, 2-1
Is a multiplier, and 2-2 is a spreading code generator. The output of the signal dividing circuit 1-2 is input to the multiplier 2-1. The spreading code generator 2-2 generates a spreading code whose period is represented by Ki, and this spreading code is input to the multiplier 2-1. The multiplier 2-1 multiplies the output signal of the signal division circuit 1-2 by the spread code which is the output signal of the spread code generation circuit 2-2,
The spread spectrum signal obtained as a result of the multiplication is output to the synthesis circuit 1-4.

<Configuration Example of Signal Dividing Circuit> FIG. 3 is a diagram for explaining a signal dividing process performed by the signal dividing circuit 1-2 in the present embodiment. In this signal division processing,
Its time input information signal in (FIG. 3 (a)) is divided into a plurality of information signals D ₁ to D _n (Figure 3 (b)). Then, these information signals D _{1 to} D _n are output within a fixed time irrespective of the amount of information (FIG. 3 (c)). Therefore, an information signal having a large amount of information among the divided information signals is output at a high transmission rate, and an information signal having a small amount of information is output at a low transmission rate. Signal dividing circuit 1-2 in this embodiment that each transmission speed information signal 1-1 is divided into a plurality of information signals S ₁ to S _n is V ₁ ~V _n By performing the aforementioned processing It is.

FIG. 4 shows a specific configuration example of a circuit for performing a signal dividing process. In the figure, 4-1 is a serial / parallel conversion circuit, and 4-2 is a synthesis circuit. Transmission speed of 3a (bp
The signal represented by s) is converted into a signal of 2a (bps) and a
(Bps). The information signal is input to the serial / parallel conversion circuit 4-1 and converted into three signals whose transmission speeds are represented by a (bps). Two of the three signals are input to the synthesis circuit 4-2. The signal is then combined with a signal whose transmission speed is represented by 2a (bps).

(2) Operation of the embodiment FIG. 5 shows the spectrum of the signal of each part of the radio transmitting station 1A. In FIG. 5, (a) shows the spread spectrum circuits 1-3-1 to 1-3-3. n input signals S _{1 to} S _n
And (b) shows a spread spectrum circuit 1-3.
Spectrum of the output signal SS ₁ ~ SS _n of -1~1-3-n, (c) is the spectrum of an output signal of the combining circuit 1-4. Hereinafter, referring to FIG. 5 in addition to FIG. 1 described above,
The operation of this embodiment will be described.

The information signal 1-1 has a transmission speed of V ₁ , V ₂ ,..., V according to the required quality by the signal dividing circuit 1-2.
is divided into n information signal S ₁ to S _n, represented by _n. These information signals S ₁ to S _n has a frequency band width corresponding to each transmission speed. In example FIG. 5 (a), the information signals S ₁ has been output at a low transmission rate, Accordingly frequency bandwidth becomes narrower. On the other hand, the information signal _Sn is output at a high transmission rate, and therefore has a wide frequency bandwidth.

As described above, information having wide and narrow bandwidths
Signal S₁~ S_nAre respectively spread spectrum circuits 1-3-3-
1 to 1-3-n. Then, each signal S₁~ S_n
In contrast, spectrum expansion using different spreading codes
However, the transmission speed is high and the frequency band
A wide information signal (eg, signal S in FIG. 5)_nAgainst)
Is spread spectrum using low spreading code.
Done. On the other hand, the transmission speed is low and the frequency bandwidth is low.
Information signal (eg, signal S in FIG. 5)₁) For
Spread spectrum using high spreading code
Is done. More specifically, the transmission speed V₁~ V_nHave
Each information signal S₁~ S_nWith respect to the above condition V₁・ K₁= V_Two
・ K_Two= ... = V_n・ K_nDiffusion rate K that satisfies₁~ K_nSpread of
Spread spectrum using codes is performed. As a result,
From each of the spread spectrum circuits 1-3-1 to 1-3-3-n,
Spread spectrum signal with exactly the same frequency bandwidth
SS ₁~ SS_nIs obtained.

Further, paying attention to the transmission speed, the transmission rate of the spread spectrum signal SS ₁ ~ SS _n is applied to each and the transmission speed V ₁ ~V _n of the previous signal S ₁ to S _n to be spread expressed as the product of spreading factor K ₁ ~K _n. Therefore, the transmission rate of the signal SS _i after the spread spectrum is V _i · K _i
Where V ₁ · K ₁ = V ₂ · K ₂ =... = V _n · K _n , so that n spread spectrum circuits 1-3-1 to 1-3 are provided.
Transmission rate of the output signal SS ₁ ~ SS _n of -n are all equal.

[0027] After being synthesized by such n signals SS ₁ was made of the resulting spread spectrum in the ~ SS _n synthesis circuit 1-4 are supplied to the transmitter 1-5, transmission antenna 1-6 Are transmitted as wireless signals in the same frequency band.

In the radio receiving station 1B, the received signal is input to n despreading circuits 1-8-1 to 1-8-n,
In these despreading circuits, despreading is performed with the same spreading code as that of the radio transmitting station 1A, and the resulting n output signals are input to demodulation circuits 1-10-1 to 1-10-n, respectively. Each output signal of the demodulation circuits 1-10-1 to 1-10-n is input to a signal combining circuit 1-11, where the signal is divided by the signal dividing circuit 1-2. The signals are combined in the reverse procedure and output as a demodulated signal.

(3) Another Embodiment The embodiment of the system in which the information signal to be transmitted is received by the radio transmitting station and divided into a plurality of information signals has been described above, but the scope of the present invention is not limited to this. Instead, for example, the following modifications are also possible.

Instead of dividing the information signal into a plurality of pieces after receiving the information signal, the wireless transmission station receives the plurality of information signals as they are. At this time, an information signal having a high required quality is received at a low transmission rate, and the information signal is subjected to spectrum spreading using a spreading code having a high spreading factor inversely proportional to the transmission rate. On the other hand, an information signal having a low required quality is received at a high transmission rate, and the information signal is subjected to spectrum spreading using a spreading code having a low spreading factor inversely proportional to the transmission rate. As described above, signals of the same frequency band subjected to spread spectrum with a processing gain corresponding to the required quality of each information signal are obtained, then combined and transmitted. The point that the wireless receiving station uses the same spreading code used in the wireless transmitting station is the same as in the above embodiment.

The radio transmitting station receives a plurality of information signals as they are. Alternatively, after receiving the information signal, the information signal is divided into a plurality of information signals. Then, among the plurality of information signals received directly or the plurality of information signals obtained by division, an information signal having a high required quality is converted into a low transmission rate, and a high spreading factor is inversely proportional to the transmission rate with respect to this information signal. Spread spectrum using the spread code of. On the other hand, an information signal having a low required quality is converted into a high transmission rate, and the information signal is subjected to spectrum spreading using a spreading code having a low spreading factor inversely proportional to the transmission rate. As described above, signals of the same frequency band subjected to spread spectrum with a processing gain corresponding to the required quality of each information signal are obtained, then combined and transmitted. This is the same as the above embodiment in that the wireless receiving station uses the same spreading code used in the wireless transmitting station.

In the above embodiment, an example has been described in which the spread spectrum circuit and the inverse spread spectrum circuit are configured in the baseband band, but the same effect can be obtained in a circuit in the intermediate frequency band.

[0033]

As described above, according to the present invention,
The n information signals can be spectrum-spread with the processing gain required for each, and can be transmitted as radio signals in the same frequency band, so that communication according to the required quality of each information signal can be performed.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a spread spectrum wireless communication system according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating an example of a spread spectrum circuit according to the embodiment.

FIG. 3 is a diagram illustrating signal division processing performed in the embodiment.

FIG. 4 is a diagram illustrating a configuration example of a signal dividing circuit according to the embodiment.

FIG. 5 is a diagram showing a spectrum of a signal of each unit in the embodiment.

FIG. 6 is a diagram illustrating a conventional spread spectrum wireless communication system.

FIG. 7 is a diagram illustrating a spectrum of a signal of each unit in a conventional spread spectrum wireless communication system.

[Explanation of symbols]

1-1 ... information signal, 1-2 ... signal division circuit, 1-3
-1 to 1-3-n ... spread spectrum circuit, 1-4 ...
... Synthesis circuit, 1-5 ... Transmitter, 1-6 ... Transmission antenna, 1-7 ... Reception antenna, 1-8 ... Receiver, 1-
9-1 to 1-9-n: despreading circuit, 1-10-1 to 1
-10-n demodulation circuit, 1-11 signal synthesis circuit,
1-12: Demodulated signal.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Toshinori Tanaka 2-3-1 Otemachi, Chiyoda-ku, Tokyo F-term in Nippon Telegraph and Telephone Corporation (reference) 5K022 EE02 EE22 EE32 5K067 AA23 CC10 DD42 DD43 HH22

Claims (6)

[Claims] The transmission rate is V ₁ , V ₂ ,..., V _n (n is 2 or more) which is a low transmission rate for an information signal having a high required quality and a high transmission rate for an information signal having a low required quality. for n pieces of the information signal is an _{integer), V 1 · K 1 =} V 2 · K 2 = ...... = V n · K n spreading factor K ₁ which satisfies the condition _{that, K 2, ..., K n} ( ≠ 1)
Are respectively multiplied by the respective spreading codes to generate n spread-spectrum signals (SS _{1 to} SS _n ), and combine these spread-spectrum signals to obtain radio signals in the same frequency band. A wireless transmission station for spread spectrum wireless communication, characterized by transmitting. 2. The transmission rate is V ₁ , V ₂ ,..., V _n (n is 2 or more) which is a low transmission rate for an information signal having a high required quality and a high transmission rate for an information signal having a low required quality. for n pieces of the information signal is an _{integer), V 1 · K 1 =} V 2 · K 2 = ...... = V n · K n spreading factor K ₁ which satisfies the condition _{that, K 2, ..., K n} ( ≠ 1)
Are respectively multiplied by the respective spreading codes to generate n spread-spectrum signals (SS _{1 to} SS _n ), and combine these spread-spectrum signals to obtain radio signals in the same frequency band. Receiving the radio signal transmitted from the transmitting radio transmitting station, performing spectrum despreading on the received radio signal using each of the plurality of spreading codes, and demodulating the results of the spectrum despreading. A radio receiving station for spread spectrum radio communication. 3. The transmission rate of n information signals (n is an integer of 2 or more) is V ₁ which is a low transmission rate for an information signal having a high required quality and a high transmission rate for an information signal having a low required quality. , V _2, ..., is converted to V _n, with respect to the converted n pieces of information signals of the transmission _{rate, V 1 · K 1 = V} 2 · K 2 = ...... = V n · K n condition: spreading factor K _1, K ₂ satisfying _{the, ..., K n (≠ 1} )
Are respectively multiplied by each spreading code to generate n spread-spectrum signals (SS _{1 to} SS _n ), and combine these spread-spectrum signals to obtain radio signals in the same frequency band. A wireless transmission station for spread spectrum wireless communication, characterized by transmitting. 4. The transmission rate of n information signals (where n is an integer of 2 or more) is V ₁ which is a low transmission rate for an information signal having a high required quality and a high transmission rate for an information signal having a low required quality. , V _2, ..., is converted to V _n, with respect to the converted n pieces of information signals of the transmission _{rate, V 1 · K 1 = V} 2 · K 2 = ...... = V n · K n condition: spreading factor K _1, K ₂ satisfying _{the, ..., K n (≠ 1} )
Are respectively multiplied by the respective spreading codes to generate n spread-spectrum signals (SS _{1 to} SS _n ), and combine these spread-spectrum signals to obtain radio signals in the same frequency band. Receiving the radio signal transmitted from the transmitting radio transmitting station, performing spectrum despreading using the plurality of spread codes on the received radio signal, and demodulating the results of the spectrum despreading; A radio receiving station for spread spectrum radio communication. 5. An information signal to be transmitted is transmitted at a low transmission rate V ₁ , V ₂ ,..., For an information signal having a high required quality and a high transmission rate for an information signal having a low required quality.
V _n (n is an integer equal to or greater than 2) information signals are divided into n information signals, and n divided spreading codes different from each other are given to each divided information signal, and V ₁ · K ₁ = _{V 2 · K 2 = ...... =} V n · K n diffusion rate K ₁ to satisfy the condition _{that, K 2, ..., K n} (≠ 1)
Are respectively multiplied by the respective spreading codes to generate n spread-spectrum signals (SS _{1 to} SS _n ), and these n spread-spectrum signals are combined. A radio transmission station for spread spectrum radio communication, wherein the radio signal is transmitted as radio signals in the same frequency band. 6. An information signal to be transmitted is transmitted at a low transmission rate V ₁ , V ₂ ,..., For an information signal having a high required quality and a high transmission rate for an information signal having a low required quality.
V _n (n is an integer equal to or greater than 2) information signals are divided into n information signals, and n divided spreading codes different from each other are given to each divided information signal, and V ₁ · K ₁ = _{V 2 · K 2 = ...... =} V n · K n diffusion rate K ₁ to satisfy the condition _{that, K 2, ..., K n} (≠ 1)
Are respectively multiplied by the respective spreading codes to generate n spread-spectrum signals (SS _{1 to} SS _n ), and these n spread-spectrum signals are combined. Receiving the radio signal transmitted from a radio transmission station transmitting the received signal as a radio signal in the same frequency band, and performing spectrum despreading on the received radio signal with the n kinds of spreading codes, respectively. The n signals obtained as a result of spectrum despreading are demodulated, and the n signals obtained by the demodulation are divided into n information signals in the radio transmitting station according to a procedure reverse to the procedure of dividing the information signals into the n information signals. A wireless receiving station for spread spectrum wireless communication, characterized by combining.