JPH07154297A - Spread spectrum transmitter - Google Patents

Abstract

PURPOSE:To reduce the contention of request channels and to improve the channel transmission efficiency by allowing a sender side terminal equipment receiving a token from a designated data channel to send data by using the designated data channel. CONSTITUTION:A system is configured with radio communication using spread spectrum processing by five transmitters A-E. The transmitter A is made up of a transmission section 11, a reception section 12 a spread code control section 13, a transmission control section 14, a CPU 15 and a host CPU 16. The transmitters B-E take similar configuration to the transmitter A. When a token of a designated data channel is requested to a transmission destination terminal equipment from the sender side terminal equipment via a request channel, the transmission destination terminal equipment uses the designated data channel to send a transmission enable to the sender side terminal equipment in response to a request of the token at the destination terminal equipment. The sender side terminal equipment receiving the transmission enable from the designated data channel uses the designated data channel to send the data.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spread spectrum transmission device in a communication network system, and more particularly to a spread spectrum transmission device for controlling a plurality of data channels using a control channel.

[0002]

2. Description of the Related Art Conventionally, as a typical communication control technology in a communication network, CSMA / CD (Carrier Sens.
There is a distributed control technology based on e Multiple Access / Carrier Detect).

This CSMA / CD is an Ethernet (Et
hernet) is a distributed control technology known as a link management procedure. It has a carrier detection function that allows a transmitting station to check the availability of a transmission path, and a multi-access function that allows multiple stations to send and receive signals using a common transmission path. The transmitting station is a technique having a collision detection function that constantly monitors whether or not stations other than the own station have started transmitting at the same time.

Therefore, in CSMA / CD, when signals are simultaneously transmitted from a plurality of stations, the amount of transmission information increases and collisions frequently occur on the transmission medium. Information that could not be transmitted due to this collision needs to be retransmitted after waiting for an appropriate time, which increases the transmission delay time and lowers the transmission efficiency.

Therefore, in Japanese Patent Laid-Open No. 4-138734, one of a plurality of channels configured by spreading code allocation is used as a control channel and another channel is used as a data channel, and a right to use each data channel is requested. And a spread spectrum communication method using a control channel for granting.

[0006] According to this technique, since the request and the grant of the usage right of each data channel are both performed on the control channel, it is possible to avoid the collision on the data channel, which is a problem of the CSMA / CD system.

[0007]

However, in this prior art, when the usage right is requested and granted frequently, contention occurs on the control channel, and the usage right is requested and granted is delayed. There is a problem.

FIG. 10 is a diagram showing a time chart of a control channel and each data channel in the case where this conventional technique is used. Here, four transceiver stations A to D
Is illustrated as an example.

FIG. 10 (a) is a diagram showing a case where there is no conflict between the request and the permission of the usage right.

As shown in FIG. 10A, for example, when the request 10a for the right to use the data channel CN1 is made from the station A to the station D via the control channel, the request 10a for the right to use. Station D, which has received the
The vacant state of N1 is confirmed, and if the data channel CN1 is vacant, the permission of use 10c of the data channel CN1 is returned to the A station using the control channel.

When the station A receives the permission 10c for using the data channel CN1 from the control channel, it transmits the data 10d to the station D by using the data channel CN1.

FIG. 10B is a diagram showing a case where there is a conflict between the request and the permission of the usage right.

As shown in FIG. 10B, in response to the request 10a for the right to use the data channel CN1 from the A station to the D station, the D station transmits the permission 10c to use the data channel CN1 to the A station. Immediately before performing the request, when the request for use right 10b of the data channel CN2 is made from the station B to the station C, the station D needs to wait for the end of the request 10b for use right.

For this reason, if the usage permission 10c from the D station to the A station and the usage right request 10b from the B station to the C station conflict with each other, a delay occurs in the data transmission 10d.

In this specific example, the case where a single contention occurs on the control channel is shown. However, considering the case where the usage right is requested and granted frequently, the delay increases cumulatively. As a result, the transmission efficiency is reduced.

Therefore, an object of the present invention is to provide a spread spectrum transmission device which solves the above problems and can improve channel transmission efficiency by reducing competition on the control channel.

[0017]

In order to achieve the above object, according to the present invention, there is provided a spread spectrum transmission apparatus for performing communication between a plurality of terminals using a plurality of channels to which different spreading codes are assigned, respectively. Of at least one of the plurality of channels is set as a request channel, and a plurality of other channels are set as data channels, and a transmitting side terminal among the plurality of terminals uses the request channel to select one of the plurality of data channels. Of 1
Transmission right request means for making a transmission right request using one designated data channel to a destination terminal among the plurality of terminals (FIG. 1).
14a), and the transmission destination terminal transmits the transmission permission to the transmission side terminal using the designated data channel in response to the transmission right request (see FIG. 1). 14b), wherein the transmission side terminal transmits data to the transmission destination terminal using the designated data channel for which the permission has been obtained.

[0018]

According to the present invention, when a transmission right request means requests the transmission right of a designated data channel from a transmission side terminal to a transmission destination terminal, the transmission right is requested by the transmission destination terminal. In response to the request, the transmission right permission means transmits the transmission permission to the transmission side terminal using the designated data channel. Then, the transmission side terminal which has received this transmission permission from the designated data channel transmits data using the designated data channel.

As a result, the channel transmission efficiency can be improved by reducing the competition of request channels.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the overall configuration of a communication system used in this embodiment and the configuration of a spread spectrum transmission apparatus (hereinafter referred to as "transmission apparatus") according to the present invention.

As shown in FIG. 1, this communication system
The five transmission devices A to E are systems configured by wireless communication using spread spectrum.

Each of the transmission devices A to E is a transmission device that transmits data to another transmission device as needed, and a request channel and a plurality of data channels are transmitted between the transmission devices by using spread spectrum modulation / demodulation. Make up.

Here, as a spreading code necessary for performing spread spectrum, a pseudo noise code (Pseudo Noise C
ode: Hereinafter referred to as "PN code". ) Use PN0 to PN3, use PN0 as the request channel, and PN1 to PN3
To each data channel.

The request channel used in this embodiment is a channel that handles only the request for the transmission right (request), and handles not only the request for the transmission right but also the transmission permission, like the control channel conventionally used. Not a channel.

The PN codes PN0 to PN3 are codes different from each other, and those having a small correlation value are used so as not to cause interference even if communication is performed simultaneously.

The transmission device A includes a transmitter 11 and a receiver 12.
A spread code control unit 13, a transmission control unit 14, a CPU
15 and an upper CPU 16.

The transmitting unit 11 permits data for requesting a transmission right to another transmission device (hereinafter referred to as "transmission right data") and transmission permission in response to a transmission right request received from another transmission device. Data (hereinafter referred to as “transmission permission data”) or original communication data created and held by the upper CPU 16 (hereinafter referred to as “communication data”).
Receive from After that, the PN code is received from the spread code control unit 13, the above various data is spread spectrum modulated using the PN code, and then transmitted through the antenna.

Upon receiving the data from the antenna, the receiver 12 uses the PN code received from the spread code controller 13 to perform spread spectrum demodulation of the data. When the data is transmission right data, the transmission permission processing unit 14b
In the case of transmission permission data, the data transmission processing unit 14c
In the case of communication data, the data is output to the data reception processing unit 14d.

The spread code controller 13 generates a PN code under the control of the CPU 15 and outputs the PN code to the transmitter 11 or the receiver 12. Here, when the transmitter 11 or the receiver 12 uses the request channel, the PN code PN0 is used, and when the data channel is used, the PN code P is used.
N1 to PN3 are generated. Also, the result of the channel search in the receiving unit 12 is notified to the transmission control unit 14 under the control of the CPU 15.

The transmission control unit 14 performs transmission control processing on the transmission right data, the transmission permission data, and the communication data. The transmission right requesting unit 14a and the transmission permission processing unit 14 are provided.
b, the data transmission processing unit 14c and the data reception processing unit 14
It is composed of d.

The transmission right request unit 14a creates transmission right data to be output to another transmission device. Specifically, first, the CPU 15 is requested to perform a channel search for a data channel and a request channel. If there is a vacancy in the data channel and the request channel, the data channel is selected from the vacant data channels and the channel number of the data channel is set. The assigned transmission right data is output to the transmission unit 11.

When the transmission permission processing unit 14b receives the transmission right data from the receiving unit 12, the transmission permission processing unit 14b extracts the channel number given to the transmission right data, and the data channel corresponding to the channel number (hereinafter referred to as "designated data channel"). ") Is requested to the CPU 15. Then, if the designated data channel is empty, transmission permission data is returned using the designated data channel.

When the data transmission processing unit 14c receives the transmission permission data from the data channel, the upper CPU 1
The communication data held by 6 is received and output to the transmission unit 11.

The data reception processing section 14d outputs the communication data received from the designated data channel to the upper CPU 16.

The CPU 15 controls the transmission control unit 14 and the spread code control unit 13. When the transmission request and the channel search request are generated in the transmission control unit 14, the CPU 15 generates a code for the spread code control unit 13. Instruct.
In the case of a channel search request, the search result is received from the spreading code control unit 13 and output to the transmission control unit 14.

The upper CPU 16 is a CPU that handles various types of communication data, and exchanges communication data held in a memory or the like with the transmission control device 14 as necessary.

Although the configuration of the transmission apparatus A has been described above, the transmission apparatuses B to E have the same configuration as the transmission apparatus A.

Next, a processing procedure for transmitting communication data from the transmission device A having the above configuration to the transmission device B will be described.

FIG. 2 is a sequence diagram showing a communication procedure for transmitting communication data from the transmission device A to the transmission device B.

As shown in FIG. 2, first, in the transmission apparatus A, a channel search for a data channel is performed (S20).
1) If there is a free data channel, the channel search for the request channel is continued (S20).
2).

If the data channel has an empty channel, the designated data channel is selected from the empty data channels and the transmission right data to which the selected data channel number is added is sent to the transmission apparatus B (S203).

For example, if there is an empty data channel corresponding to the PN code PN1 and this data channel is selected as the designated data channel, the transmission right data to which the designated data channel number PN1 is added is transmitted using the request channel. Send to B.

Then, the transmission device B which has received this transmission right data via the request channel extracts the designated data channel number PN1 from the transmission right data and checks the vacant state of the designated data channel PN1.

As a result, if the designated data channel PN1 has a free space, it is determined that the transmission is permitted, and if the designated data channel PN1 has no free space, it is determined that the transmission is impossible (S204).

When it is determined that the transmission is permitted, the transmission permission data is transmitted to the transmission apparatus A using the designated data channel PN1 (S205).

Then, the transmission apparatus A which has received the transmission permission data from the designated data channel PN1 transmits the communication data to the transmission apparatus B via the designated data channel (S).
206, S207).

If it is determined in S204 that transmission is not possible, a channel search is performed again after a lapse of a predetermined period to search for a vacant state of the designated data channel.

By performing the above series of processing, the transmission permission data can be received from the transmission device B using the designated data channel in response to the transmission of the transmission right data from the transmission device A.

Next, the data transmission procedure will be described in more detail using the time charts of the request channel and each data channel.

FIG. 3 is a diagram showing an example of a time chart of each channel.

In FIG. 3, the transmission right request 3a from the transmission apparatus A to the transmission apparatus B, the transmission right request 3b from the transmission apparatus C to the transmission apparatus D, and the transmission right request from the transmission apparatus E to the transmission apparatus B are performed. 3C shows a case where 3c is continuously performed.

First, the transmission right request 3a from the transmission apparatus A
Receiving the transmission, the transmission apparatus B receives the designated data channel number PN1.
Is extracted from the transmission right data, and the data channel PN1
Is used to permit the transmission device A to transmit 3e. Then, the transmission device A that has received the transmission permission performs data transmission 3f to the transmission device B using the data channel PN1.

Here, since the transmission permission data 3e returned from the transmission device B to the transmission device A is transmitted using the designated data channel PN1 instead of the request channel,
The request channel is idle even while the transmission permission data 3e is being transmitted.

Therefore, it can be seen that the transmission right request 3b from the transmission device C to the transmission device D does not conflict with the transmission permission data 3e when the request channel is used.

Further, since the transmission device C can search that the data channel PN1 is in use when requesting the transmission right from the transmission device D, the transmission device C selects the empty data channel PN2 as the designated data channel. , Requesting the transmission right 3b.

Therefore, the transmission permission 3g from the transmission device D to the transmission device C and the data transmission 3h from the transmission device C to the transmission device D are performed using the designated data channel PN2.

When the transmission device E makes a transmission right request 3c to the transmission device B, since the transmission device B is receiving the data from the transmission device A, the transmission permission to the transmission device E is not permitted. I don't know. Therefore, after the transmission device B has finished receiving the data, the transmission device E newly makes a request 3d for the transmission right to the transmission device B.

As described above, in the communication system using the transmission apparatus according to the present invention, the transmission permission data is transmitted using the designated data channel instead of the request channel, so that contention on the request channel is reduced. ing.

Next, the series of processes shown in FIG. 3 will be described in more detail using a time chart for each transmission device.

FIG. 4 is a diagram showing a time chart for each transmission device.

In the transmission device A, in order to transmit data to the transmission device B, first, the request channel search 4a, that is, the carrier sense of the request channel is performed, and after confirming that the request channel is empty, the request is transmitted. The transmission right request 3a is transmitted to the transmission device B which is the destination terminal using the channel.
After that, when the transmission permission from the designated data channel PN1 is waited and the transmission permission 3e is received, the data 3f is transmitted to the transmission device B using the designated data channel PN1.
Send to.

In the transmission device B, when the transmission right request 3a from the transmission device A is received from the request channel,
Designated data channel number PN1 included in the transmission right request
To retrieve 4e of the designated data channel PN1
I do. Then, after confirming that the designated data channel PN1 is empty, the transmission permission 3e is transmitted to the transmission apparatus A using the designated data channel.

In the transmission device C, in order to perform data transmission to the transmission device D, the request channel search 4b is performed similarly to the transmission device A, and after confirming that the request channel is empty, the request channel is searched. The transmission right request 3b is transmitted using the channel. Then, it shifts to a transmission permission waiting state from the designated data channel PN1, receives a transmission permission 3g from the designated data channel PN1, and then performs data transmission 3h using the designated data channel PN1.

When the transmission device D receives the transmission right request 3b from the request channel, it searches the designated data channel PN1 4f. In this case, since the designated data channel PN1 is used by the transmission permission 3e from the transmission device B to the transmission device A, the transmission permission cannot be transmitted. Therefore, after waiting for a certain period of time, the designated data channel PN1 is searched again 4g, and then the transmission permission 3g is transmitted using the designated data channel PN1.

As described above, according to the present invention, the contention of the request channel can be reduced, although the collision remains in the designated data channel.

It should be noted that in the above-mentioned specific example, the case where the designated data channel PN1 conflicts is created. However, since the number of data channels can be made larger than the request channel in practice, the conflict can be reduced. Becomes

By the way, the above transmission device A and transmission device C
The packet length (L) of the transmission right request transmitted by the device and the search time (T) for the transmission devices B and D to search the data channel PN1 have the following constraint conditions.

L> 2 × (farthest station propagation delay time) × (transmission speed) T> 2 × (farthest station propagation delay time) + in-station processing time Hereinafter, such constraint conditions will be specifically described.

FIG. 5 is a diagram for explaining the constraint condition of the packet length (L) of the transmission right request.

Here, the packet length (L) of the transmission right request
In order to obtain the minimum value of, the transmission apparatus A and the transmission apparatus B are at the farthest distance that they can communicate with each other, and the case where the transmission apparatus C and the transmission apparatus D are located very close to the transmission apparatus A will be considered. Note that the transmission device C is closer to the transmission device A than the transmission device D.

Among the symbols shown in FIG. 5, "Re
"q" is the transmission right request packet, "P" is the transmission permission packet, "Tdly" is the maximum propagation delay time between the transmission devices A and B, and "Lp" is the packet length of the transmission right request Req. “Ts” indicates the search time before the transmission of the transmission permission packet.

Further, "t1" is the transmission completion time of the Req transmitted from the transmission apparatus A, "t2" is the time when the beginning of the Req transmitted from the transmission apparatus C reaches the transmission apparatus D, and "t3". Is the transmission start time of P transmitted from the transmission device D, “t4” is the time when the head of the P transmitted from the transmission device B passes through the transmission device D, and “t5” is the P transmitted from the transmission device B. "V" indicates the time at which the head of the packet arrives at the transmission device A, and "v" indicates the transmission rate.

In this case, the relational expression t5 = t1 + 2Tdly + Ts t2 = t1 + a + b t3 = t2 + Lp / v t4 = t5-c is obtained. Here, “a” is the transmission device A
From the transmission right request packet passing through the transmission device D, "b" is a transmission delay between the transmission devices C and D, and "c" is between the transmission devices A and D. The transmission delay is shown.

If t3 is larger than t4, P transmitted from the transmission device B can be searched for in the transmission device D, so that t3> t4 is obtained. Then, by substituting the above relational expressions into this inequality and rearranging, it becomes Lp / v> 2Tdly-abc. Considering that a, b, and c are approximately 0, Lp> 2Tdly · v is obtained.

From this, it is understood that the packet length (L) of the transmission right request packet needs to be at least twice the product of the farthest station propagation delay time (Tdly) and the transmission rate (v).

Next, the search time of the data channel will be described.

FIG. 6 shows the data channel search time (T
It is a figure explaining the constraint condition of s).

Here, in order to obtain the minimum value (Ts-min) of the search time of the data channel, the transmission apparatus A and the transmission apparatus B are at the farthest distance that they can communicate with each other, and the transmission apparatus C.
Consider that the transmission device A is located very close to the transmission device A and the transmission device D is located very close to the transmission device B.

It is assumed that the transmission permission P is transmitted from the transmission device D to the transmission device C immediately before the transmission right request Req transmitted from the transmission device A arrives at the transmission device B. Further, among the symbols shown in FIG. 6, "DATA" indicates communication data and "Td" indicates delay time in the transmission device C.

In this case, the search time Ts of the data channel is the transmission delay of P transmitted from the transmission device D to the transmission device C (approximately equivalent to Tdly), Td, and the transmission device C to the transmission device D. If it is not more than the sum of the transmission delay of DATA transmitted to (approx. Equivalent to Tdly), P to be transmitted from the transmission device B and DATA transmitted from the transmission device C will collide. It is necessary to satisfy Ts> 2Tdly + Td.

That is, the minimum value Ts-min of the search time of the data channel is the farthest station propagation delay time (Tdly).
That is, a constraint condition of not less than twice the processing time (Td) in the own station is generated.

Next, the transmission processing procedure and the reception processing procedure of the transmission apparatus A will be described with reference to the flowcharts shown in FIGS. 7 and 8.

FIG. 7 is a flowchart showing the flow of the transmission processing procedure.

As shown in FIG. 7, first, a data channel is searched to determine a designated data channel (S701), and the presence or absence of a non-communication data channel is confirmed (S702). If there is, the designated data channel is selected.

On the other hand, if there is no non-communication data channel, after waiting for a certain period of time (S703), the process proceeds to S701.

Here, when there are a plurality of non-communication data channels, the designated data channel is selected based on the priority given to the data channel, or the designated data channels are selected so that the frequencies of use are equal. be able to.

Next, when the designated data channel is determined, the request channel is searched (S704) and it is confirmed whether the request channel is non-communication (S70).
5).

When this request channel is in communication, data cannot be transmitted, so that the process proceeds to S704 after waiting for a fixed time (S706).

On the other hand, when the request channel is non-communication, the transmission right data to which the information of the designated data channel is added is transmitted to another transmission device through the request channel (S707).

After that, the designated data channel is monitored for a certain period of time (S708), and when the transmission permission data is received from the designated data channel (S709), the data is transmitted using the designated data channel (S710). On the other hand, if the transmission permission data cannot be received, a request is made again after waiting for a certain period of time (S711).

Since the request channel used to transfer the transmission right data is more likely to have a space than the data channel, the waiting time in S706 is shorter than the waiting time in S703.

Next, a reception processing procedure in the transmission apparatus A will be described.

FIG. 8 is a flow chart showing the flow of the reception processing procedure.

As shown in FIG. 8, when the transmission process is not performed, the request channel is constantly monitored (S80).
1) Confirm whether or not there is transmission right data addressed to the own station (S80)
2).

When the transmission right data addressed to the own station is received, it is judged whether or not the transmission is permitted (S80
3) When permitting the transmission, the designated data channel number included in the request channel is taken out and the designated data channel is searched (S804). If this designated data channel is in an idle state with no communication (S80
5) After waiting for a certain period of time (S806), the process proceeds to S804.

On the other hand, when the designated data channel is idle, the transmission permission is transmitted using the designated data channel (S807), and the designated data channel waits for data. Then, after confirming the transmission permission, the data transmitted is received (S808).

By performing the transmission process and the reception process described above, it is possible to perform communication using the request channel for the transmission right data and the designated data channel for the other data.

By the way, in the above embodiment, the destination terminal performs the search of the designated data channel after receiving the transmission right request from the request channel, and waits for a certain period of time before performing the search (S804-). S80
In 6), if there is little competition in the designated data channel, it is not necessary to search for the designated data channel, so that the reception processing procedure can be simplified.

FIG. 9 is a diagram showing a reception processing procedure of the transmission device in such a case.

As shown in FIG. 9, when the transmission process is not performed, the request channel is constantly monitored (S90
1) Confirm whether or not there is transmission right data addressed to the own station (S90).
2).

When the transmission right data addressed to the own station is received, it is determined whether or not the transmission is permitted (S90
3) In the case of permitting the transmission, after transmitting the transmission permission data using the designated data channel (S904), the data is received from the designated data channel (S905).

As described above, in this embodiment, the request channel is used for the transmission right data transmitted by the transmission right requesting unit 14a, and the transmission permission data and the data transmission processing unit are transmitted from the transmission permission processing unit 14b. Since the data to be transmitted is configured to be transmitted using the designated data channel, contention on the request channel can be reduced and the channel transmission efficiency can be improved.

Further, since the transmission permission data is transmitted using the designated data channel, it is possible to early recognize in another transmission device that the data transmission using the designated data channel will continue.

In the present embodiment, the case where the PN code is used as the spreading code has been shown, but the present invention is not limited to this, and is applicable to the case where other spreading code is used. You can Further, although the case where one request channel is used is shown in the present embodiment, the present invention can also be applied when a plurality of request channels are provided.

Further, although the present embodiment has been described with respect to the wireless communication using the spread spectrum system, it is apparent that the present invention can be applied to the wired communication and has the same effect.

[0107]

As described in detail above, according to the present invention, when a transmission right is requested from a transmission side terminal to a transmission destination terminal via a request channel, the transmission right is transmitted at the transmission destination terminal. In response to the request, the transmission permission is transmitted to the transmission side terminal using the designated data channel. Then, since the transmitting side terminal which has received the transmission right from the designated data channel is configured to perform data transmission using the designated data channel, the following advantages can be obtained.

1) It is possible to reduce contention for request channels and improve channel transmission efficiency.

2) It is possible to construct an efficient communication system with less data retransmission.

3) Effective use of frequencies becomes possible.

[Brief description of drawings]

FIG. 1 is a block diagram showing an overall configuration of a communication system used in this embodiment and a configuration of a spread spectrum transmission apparatus according to the present invention.

FIG. 2 is a diagram showing a data transmission sequence performed between the spread spectrum transmission apparatuses shown in FIG.

3 is a diagram showing a time chart of a request channel and a data channel of the communication system shown in FIG.

FIG. 4 is a diagram showing a time chart for each spread spectrum transmission apparatus shown in FIG.

FIG. 5 is a diagram illustrating a constraint condition of a packet length of a transmission right request.

FIG. 6 is a diagram illustrating a constraint condition of a transmission permission search time.

7 is a flowchart showing a transmission processing procedure of the spread spectrum transmission apparatus A shown in FIG.

8 is a flowchart showing a reception processing procedure of the spread spectrum transmission apparatus A shown in FIG.

9 is a flowchart showing a simple reception processing procedure of the spread spectrum transmission apparatus A shown in FIG.

FIG. 10 is a diagram showing a time chart of each channel in the related art.

[Explanation of symbols]

11 transmitter, 12 receiver, 13 spreading code controller,
14 transmission control unit, 14a transmission right request unit, 14b transmission permission processing unit, 14c data transmission processing unit, 15 CP
U, 16 Upper CPU

Claims (1)

[Claims] 1. A spread spectrum transmission apparatus for performing communication between a plurality of terminals using a plurality of channels to which different spreading codes are assigned, wherein at least one of the plurality of channels is a request channel and another is A plurality of channels is set as a data channel, and the transmitting side terminal among the plurality of terminals uses the request channel to request the transmission right using one designated data channel among the plurality of data channels. A transmission right requesting means for performing a transmission right terminal among a plurality of terminals is provided, and the transmission destination terminal transmits to the transmission side terminal using the designated data channel in response to the transmission right request. A transmission permission transmission means for transmitting a permission, wherein the transmission side terminal uses the designated data channel for which the permission is obtained. Serial spread spectrum transmission apparatus and transmits the data to the destination terminal.