JP2002077178A - Optical radio communication equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify a communication procedure, to eliminate a pressure to an optical channel and to perform prompt half-duplex optical communication. SOLUTION: In an optical radio communication system, optical signals are transmitted and received by half-duplex optical communication between plural slave units and a master unit. The master unit receives frame data F from the slave unit to which an optical channel use permission PM is supplied last, then transmits the optical channel use permission PM to the slave unit, stands by for fixed time and transmits optical channel free signals SP to the other plural slave units when a new frame F is not transmitted from the slave unit within the fixed time. In the meantime, the slave unit transmits the frame data F to the master unit, then stands by for the fixed time and transmits new frame data F as needed to the master unit at the time of detecting optical channel use permission signals PM from the master unit within the fixed time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diffused optical wireless communication apparatus for transmitting a signal over a wide range by optical wireless communication, and a narrowly oriented optical wireless communication apparatus for transmitting and receiving information between the diffused optical wireless communication apparatus by optical wireless. The present invention relates to a rectangular optical wireless communication device.

[0002]

2. Description of the Related Art Conventionally, a plurality of information processing devices such as personal computers are interconnected to each other to form a LAN (Local Arrangement).
ea Network), these information processing devices
For example, they are often connected by a wire such as a coaxial cable or an optical cable. Wired connection is advantageous in that there are few data errors due to extraneous noise because a mechanically secure connection is possible, but the wiring work is complicated and requires work for each layout change. There is a point.

In recent years, there has been an increasing demand for data transmission by interconnecting portable information processing apparatuses such as personal computers such as laptops, books and palmtops, and electronic notebooks. On the other hand, these portable information processing devices are devices originally intended to be moved and used, and it is extremely rare that they are moved while being connected by wire. For this reason, when data transmission is performed by connecting these portable information processing devices to each other, a connector must be connected and disconnected each time the device is moved, and such a connection operation is very troublesome. In addition, if the connector is repeatedly inserted and removed, there is a possibility that mechanical damage of a connection portion such as the connector may occur.

[0004] For these reasons, when data is transmitted and received between various types of information processing equipment, not limited to the stationary type and the portable type, all or a part of the transmission path is made wireless to reduce wired connections. There is a request to want.

[0005] Here, as the method of the wireless transmission, there are a method using radio waves as a transmission medium and a method using light as a transmission medium. High-speed data transmission can be realized by using any of these radio wave and light transmission media. However, radio waves are subject to legal regulations, and wireless transmission using light without any legal restrictions is not possible. It is advantageous.

An Ethernet (registered trademark) LAN, which has the highest penetration rate among wired LANs, has a transmission speed of, for example, 10 Mbps.
It is desirable to have a transmission rate of 0 Mbps.

[0007] For this reason, the present applicant has disclosed in Japanese Patent Application Laid-Open No. 8-56198 "a method and an apparatus for canceling return light in optical wireless communication" which realizes a transmission speed of 10 Mbps by using light as a transmission medium. Is disclosed.
The technology described in this publication realizes full-duplex communication by optical wireless between a base unit mounted on a ceiling and a slave unit installed in a room. A method is adopted in which the transmission signal is subtracted to remove an adverse effect due to reflected light. That is, in optical wireless transmission, light is transmitted to free space and light from free space is received. For example, the transmission signal light transmitted by itself is transmitted by an object located near the other device. There is a problem that communication signals from the other party cannot be accurately taken out due to reflection or the like and input to the receiving unit. For this reason, in the technique described in the publication, a part of a transmission signal is branched, and the level and phase of the signal are adjusted and added to a reception signal, thereby canceling a signal due to return light.

In recent years, higher transmission speeds have been desired, and even in the above-mentioned optical wireless communication system, further higher transmission speeds are required.

Here, the transmission speed is, for example, 100 Mbps.
Consider optical wireless communication.

[0010] When optical wireless communication is performed at a transmission rate of 100 Mbps, one wavelength of the fundamental frequency of modulation is 30,000.
0 km / 125 MHz = 2.4 m.

Therefore, for example, if the transmission signal light from the transmitting unit (light emitting unit) of the optical wireless communication device is reflected at, for example, 1.2 m ahead and returns to the receiving unit (light receiving unit) as well, The arriving return light due to the reflection is a one-wavelength shift from the transmission signal light transmitted by the light emitting unit. In other words, depending on the distance between the light emitting unit and the reflecting object (also the distance between the reflecting object and the light receiving unit), the phase of the return light due to the reflection is determined by the original signal (transmission signal). It means that it is impossible to predict what phase the light will be. Also, for example, the phase of the reflected return light when the transmission signal light from the transmission unit of the optical wireless communication device returns to the reception unit after being reflected at, for example, 0.5 m, and, for example, from the transmission / reception unit of the optical wireless communication device. The phase of the signal light sent from another optical wireless communication device that is 1 m away is the same, and in this case, there is a possibility that the return light and the signal light cannot be distinguished.

For these reasons, in order to realize optical wireless communication at a transmission rate of 100 Mbps, a reflection return light canceling circuit that can handle light having various phases and amplitudes is required.

However, mounting a reflection return light canceling circuit capable of coping with light of various phases and amplitudes in an optical wireless communication device as described above is practically very difficult in terms of the size and cost of the device. Have difficulty.

As described above, when optical wireless communication is performed at a transmission rate of 100 Mbps, for example, transmission (light emission) from the slave unit is performed without performing the above-described full-duplex communication in which reflected return light is a problem. ), Transmission request application processing (ID exchange, etc.) is performed to the base unit, and when the permission is given, transmission is performed from the child unit to the base unit, so-called half-duplex communication is performed. It is conceivable to realize optical wireless communication that eliminates the influence of reflected return light.

Hereinafter, in an optical wireless communication system for performing half-duplex communication, an optical wireless communication device as a slave (hereinafter simply referred to as a slave) is changed from an optical wireless communication device as a master (hereinafter simply referred to as a master). A description will be given of a signal transmission / reception timing image when transmitting a signal in a frame unit.
In the optical wireless communication system described below, it is assumed that the master unit is connected by wire to another system via a network trunk, and the slave unit is connected by wire to a terminal such as a personal computer. Further, the master unit includes a trunk side transmission unit that transmits a signal to the network trunk, a trunk line receiving unit that receives a signal from the network trunk, a light emitting unit that transmits an optical signal to the slave, and an optical signal from the slave. A slave unit that receives an optical signal from the master unit, a light emitting unit that sends an optical signal to the master unit, and a terminal-side transmission unit that sends a signal to the terminal. And a terminal-side receiving unit that receives a signal from the terminal.

In FIG. 15, the master unit does not have a function of transmitting a signal in frame units (hereinafter, also referred to as a frame or frame data as appropriate) transmitted from the slave unit to, for example, the slave unit. FIG. 16 shows a signal transmission / reception timing image in the optical wireless communication system in the case of FIG.
2 shows a signal transmission / reception timing image in the optical wireless communication system in a case where the master unit has a function of transmitting a signal in a frame unit transmitted from the slave unit to the slave unit, for example. In an optical wireless communication system with a transmission rate of 100 Mbps, there is not much realization of the use of half-duplex optical communication itself.
FIG. 16 and FIG. 16 show signal transmission / reception timing images which are considered to be employed when performing half-duplex optical communication.

First, in FIG. 15, when the terminal transmits frame data f1 generated by the terminal to the master unit, the master unit optically transmits an optical line idle signal sp indicating an idle optical line as t1 in the figure. You. The slave unit that has detected (received) the optically transmitted optical line free signal sp, when it wants to use the optical line, sends a response to the master unit as shown at t2 in the figure, as shown by t2 in the figure.
Optical line use request signal re for requesting use of the optical line
, An optical preamble signal P is added to the optical signal for optical transmission. When receiving the optical line use request signal re, the master unit, when the optical line is available, allows the slave unit to use the optical line use permission signal pm for permitting the use of the optical line as shown at t3 in the figure. , An optical preamble signal P is added to the optical signal for optical transmission. The slave unit which has received the optical line use permission signal pm from the master unit transmits the frame data f1 received from the terminal to the light emitting unit by wire as shown by t4 in the figure, and further transmits the frame data f1 to the master unit from the light emitting unit. The optical preamble signal P and the frame data f1 are optically transmitted as at t5. The master unit transmits the frame data f1 sent from the slave unit to the network main line by wire as shown at t6 in the figure. The operation for the frame data f2 is the same as that for the frame data f1.

Next, in FIG. 16, when transmitting the frame data f1 generated by the terminal from the slave unit to the master unit, first, as shown at t1 in the figure, the master unit transmits an optical line idle signal sp. The slave unit that has detected (received) the optically transmitted optical line free signal sp transmits the optical preamble signal P and the optical line use request signal re to the master unit as indicated by t2 in the figure. When receiving the optical line use request signal re, the master unit optically transmits the optical preamble signal P and the optical line use permission signal pm to the slave unit as shown at t3 when the optical line can be used. . Optical line use permission signal p from master unit
The slave unit having received m transmits the frame data f1 received from the terminal by wire to the light emitting unit as shown at t4 in the figure, and further transmits the frame data f1 from the light emitting unit to the master unit optically as shown at t5 in the figure. The master unit transmits the frame data f1 sent from the slave unit to the network main line by wire as shown at t6 in the figure.

Up to this point, it is the same as FIG.
In the case of, the master unit transmits the frame data f1 received by the light receiving unit and transmitted to the network trunk line to the light emitting unit as shown at t7 in the figure, and further transmits the reflected light back to the slave unit as shown at t8 in the figure. The slave unit that has received the frame data f1 that is transmitted back from the master unit by optical transmission transmits the frame data f1 to the terminal by wire as indicated by t9 in the figure.
Thus, the terminal knows that the frame data f1 has been transmitted normally. The operation for the frame data f2 is the same as that for the frame data f1.

In FIGS. 15 and 16, an example has been described in which the frame data received from the terminal is transmitted from the child device to the parent device, and further transmitted from the parent device to the network trunk.
In other words, the same procedure as described above is basically applied to the case where the frame data received from the network trunk is transmitted from the parent device to the child device, and further from the child device to the terminal.

As described above with reference to FIGS. 15 and 16, according to the half-duplex optical communication, for example, when the slave unit optically transmits the frame data received from the terminal to the master unit, the slave unit: Detects an optical line free signal from the base unit, issues an optical line use request to the base unit, obtains the optical line use permission from the base unit, and transmits the frame data received from the terminal to the base unit. It is considered that such a method is adopted.

[0022]

However, in the above-described example of the half-duplex optical communication, the optical preamble for phase synchronization must be used for the optical transmission from the slave to the master and the optical transmission from the master to the slave. In addition to having to put the signal P, the slave unit needs to obtain the optical line use permission from the master unit and then transmit light, and in order to obtain the use permission, an application (optical line use request signal re) And approval (optical line use permission signal pm)
Communication procedures are needed.

That is, in half-duplex optical communication, a large amount of time is required for a communication procedure for obtaining a preamble signal and permission to use the optical line, and the optical line is squeezed, resulting in a reduction in communication performance.

The present invention has been made in view of the above-mentioned problems, and has been made in view of the above-mentioned circumstances, and an optical wireless communication apparatus which simplifies a communication procedure, eliminates pressure on an optical line, and enables quick half-duplex optical communication. The purpose is to provide.

[0025]

According to the present invention, there is provided an optical wireless communication apparatus for transmitting and receiving an optical signal to and from a plurality of other optical wireless communication devices by half-duplex optical communication. A communication device, as means for solving the above-mentioned problem, a line free signal generating means for generating an optical line free signal indicating the release of an optical line, and an optical line transmitted from the other optical wireless communication device An optical line use request signal detecting means for detecting a use request signal; an optical line use permission signal generating means for issuing an optical line use permission signal to one of the other optical wireless communication devices; and Storage means for storing an optical wireless communication device to which the optical line use permission was finally given among other optical wireless communication devices, and after receiving a signal from the optical wireless communication device to which the optical line use permission was finally given, Finally, give permission to use the optical line When the optical line use permission signal is transmitted to the obtained optical wireless communication device and the optical wireless communication device waits for a certain period of time, and there is no new signal transmission from the optical wireless communication device to which the last optical line use permission was given within the certain time period Transmission / reception control means for transmitting the optical line idle signal to the plurality of other optical wireless communication devices.

According to a second aspect of the present invention, there is provided an optical wireless communication apparatus for transmitting and receiving an optical signal to and from a plurality of other optical wireless communication apparatuses by half-duplex optical communication. As a means for solving the above problem, a line free signal generating means for generating an optical line free signal indicating the release of an optical line and an optical line use request signal transmitted from the other optical wireless communication device are detected. An optical line use request signal detecting unit, an optical line use permission signal generating unit that issues an optical line use permission signal to one of the other optical wireless communication devices, and the plurality of other optical wireless communications A storage unit for storing an optical wireless communication device to which the optical line use permission is finally given among the devices, and after receiving a signal from the optical wireless communication device to which the optical line use permission is finally given, the plurality of other optical wireless communication devices. The light for communication equipment Waiting for a fixed time by transmitting a line free signal, and when not receiving an optical line use request signal from any of the plurality of other optical wireless communication devices within the fixed time, giving an optical line use permission at the end. When the optical line communication permission signal is transmitted to the optical wireless communication device, and the optical wireless communication device waits for a predetermined time, and there is no new signal transmission from the optical wireless communication device to which the last optical line use permission is given within the predetermined time. Transmission / reception control means for transmitting the optical line idle signal to the plurality of other optical wireless communication devices.

According to a third aspect of the present invention, there is provided an optical wireless communication apparatus for transmitting / receiving an optical signal to / from another optical wireless communication apparatus by half-duplex optical communication. As a means for solving the problem, a line free signal detecting means for detecting an optical line free signal indicating the release of the optical line transmitted from the other optical wireless communication device, and when the optical line free signal is detected An optical line use request signal generating means for issuing an optical line use request signal to the other optical wireless communication device, and an optical line use signal for detecting an optical line use permission signal transmitted from the other optical wireless communication device Permission signal detection means, and waits for a fixed time after transmitting a signal to the other optical wireless communication device, when detecting an optical line use permission signal from the other optical wireless communication device within the fixed time, The other optical wireless communication device Against, and a transmission and reception control means for transmitting a new signal as needed.

According to a fourth aspect of the present invention, there is provided an optical wireless communication apparatus for transmitting and receiving an optical signal to and from another optical wireless communication apparatus by half-duplex optical communication. As a means for solving the problem, a line free signal detecting means for detecting an optical line free signal indicating the release of the optical line transmitted from the other optical wireless communication device, and when the optical line free signal is detected An optical line use request signal generating means for issuing an optical line use request signal to the other optical wireless communication device, and an optical line use signal for detecting an optical line use permission signal transmitted from the other optical wireless communication device The permission signal detecting unit, after transmitting a signal to the other optical wireless communication device, ignores the first optical line idle signal transmitted from the other optical wireless communication device, and waits for a predetermined time, and The other light within a certain time Upon detection of a light line usage permission signal from the line communication device, to the other optical wireless communication device, and a transmission and reception control means for transmitting a new signal as needed.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows a schematic configuration of a main part of an optical wireless communication system including an optical wireless communication apparatus according to an embodiment of the present invention.

The optical wireless communication system according to the present embodiment is a system connected to a trunk network such as Ethernet (registered trademark) for transmitting and receiving data by packet (frame) transmission, as shown in FIG. A network trunk 2 and terminals (for example, terminals 4 (4a, 4b, 4
c)), an optical wireless communication device (hereinafter, referred to as a parent device)
The connection is made using half-duplex optical communication by an optical wireless communication device (hereinafter, referred to as a child device 3 (3a, 3b, 3c)) as a child device. The terminal 4 includes a network interface card (NI) in addition to a personal computer or the like.
C) and hubs such as hubs are also included.

FIG. 2 shows basic signals in the optical wireless communication system of FIG. 1 when frame data F generated by terminal 4 is transmitted from slave unit 3 to master unit 1 and further transmitted to network trunk 2. 4 shows a transmission / reception timing image.

In FIG. 2, when transmitting the frame data F1 generated by the terminal 4 from the slave unit 3 to the master unit 1, first, the master unit 1 indicates an empty optical line as indicated by T1 in the figure. The handset 3 that has optically transmitted the optical line vacant signal SP, and has detected (received) the optically transmitted optical line vacant signal SP,
When the user himself / herself wants to use the optical line, as shown at T2 in the figure, the optical preamble signal P is added to the optical line use request signal RE for requesting use of the optical line, and the optical transmission is performed. Base unit 1 receiving this optical line use request signal RE
When the optical line is available, the optical preamble signal P is added to the optical line use permission signal PM for permitting the slave unit 3 to use the optical line, as indicated by T3 in FIG. It transmits and waits for a certain period of time for the frame data F1 to be sent from the slave unit 3. Optical line use permission signal PM from master unit 1
Receives the frame data F within a predetermined time.
1 can be transmitted to the base unit 1, the frame data F1 from the terminal 4 is transmitted by wire to the light emitting unit as indicated by T4 in the figure, and the light emitting unit transmits the optical preamble signal P to the base unit 1.
And the frame data F1 is optically transmitted as indicated by T5 in the figure. If the frame data F1 is transmitted from the slave unit 3 within a predetermined time after the transmission of the optical line use permission signal PM, the master unit 1 transmits the frame data F1 to the network trunk line 2 as indicated by T6 in the figure. Send by wire.

Next, the master unit 1 transmits the frame data F1
When the reception is completed, an optical line use permission signal PM for the next frame data F2 is transmitted to the same slave unit (slave unit to which the optical line use permission was given last) 3 as indicated by T13 in FIG. It waits for a certain period of time for the frame data F2 to be sent from the slave unit 3. The slave unit 3 that has received the optical line use permission signal PM receives the next frame data F2 within a predetermined time.
Can be transmitted to the base unit 1 or when it is necessary to transmit the next frame data F2 within a predetermined time, the same as the case of the frame data F1, the next frame data F2 generated by the terminal 4 is transmitted. Is transmitted by wire to the light emitting unit as indicated by T14 in the figure, and further, the light emitting unit optically transmits the optical preamble signal P and the frame data F2 to the master unit 1 as indicated by T15 in the figure. That is, the slave 3 in this case transmits the next frame data F2 to the master 1 without optically transmitting the optical line use request signal RE to the master 1. The master unit 1 receives the frame data F2 if the next frame data F2 is sent from the slave unit 3 within a predetermined time after the generation of the optical line use permission signal PM by T13 in the figure. Wired transmission is performed to the network trunk line 2 as in T16.

Next, the master unit 1 transmits the frame data F2
When the reception is completed, the same slave unit (the slave unit to which the optical line use permission is finally given) 3 is sent an optical line use permission signal PM for the next frame data F3 as indicated by T23 in the figure.
Send

Here, if the next frame data is not transmitted from the same slave unit 3 within a certain time after the optical line use permission signal PM is given to the slave unit 3, the master unit 1
The optical line is once released to all the slaves 3.

On the other hand, after the optical line is released as described above, the slave unit 3 transmits the next frame data F3 to the master unit 1 in the same manner as when transmitting the frame data F1. Detects (receives) an optical line free signal SP optically transmitted from the base unit 1 as shown at T31 in the figure, and sends an optical preamble signal P and an optical line use request signal RE to the base unit at T3 in the figure.
Optical transmission is performed as in 2.

When receiving the optical line use request signal RE, the master unit 1 sends an optical preamble signal P and an optical line use permission signal to the slave unit 3 as indicated by T33 in FIG. The PM is optically transmitted, and a certain period of time is waited until frame data is transmitted from the slave unit 3. The slave unit 3 that has received the optical line use permission signal PM from the master unit 1 can transmit the next frame data F3 within a certain time or transmit the next frame data F3 within a certain time. When transmission is required, frame data F3 from terminal 4 is optically transmitted to base unit 1, and
The base unit 1 converts the frame data F3 sent from the handset 3 within a certain time after issuing the optical line use permission signal PM,
Wired transmission to the network trunk 2 is performed.

In the description of FIG. 2, the basic operation has been described without specifying the slave 3, but as in the optical wireless communication system of FIG. 1, each of the slaves 3a, 3b, 3c is a parent. In the case of a system capable of optical communication with the device 1, optical communication is performed according to the procedure shown in FIG. That is, when there are a plurality of slave units as in the optical wireless communication system of FIG. 1, if the signal transmission / reception timing image of FIG. 2 is used as it is, a transmission / reception cycle is performed by one of the slave units. Since there is a risk of being monopolized, in the present embodiment, it is possible to prevent the transmission cycle from being monopolized by one slave unit by performing optical communication with the transmission / reception timing image as shown in FIG. .

In FIG. 3, for example, when the frame data F1a generated by the terminal 4a is transmitted from the slave unit 3a to the master unit 1, first, an optical line optically transmitted from the master unit 1 as indicated by T1 in FIG. The slave unit 3a that has detected (received) the empty signal SP transmits the optical preamble signal P and the optical line use request signal REa to the master unit 1 optically as indicated by T2a in the figure. Base unit 1 receiving this optical line use request signal REa
When the optical line can be used, the optical preamble signal P and the optical line use permission signal PMa are optically transmitted to the slave unit 3a as indicated by T3a in the figure, and the frame data is transmitted from the slave unit 3a. Wait for a certain time to come.

Here, the optical line free signal SP and the optical line use permission signal PMa, which are optically transmitted from the master unit 1 as T1 and T3a in the figure, are transmitted to the slave units other than the slave unit 3a (the slave unit in the following description). 3b). At this time,
The slave unit 3b sends an optical line use request signal RE to the master unit 1.
Before the optical transmission of b, the slave unit 3
a transmits an optical line use permission signal PMa to the base unit 1, the slave unit 3 b recognizes that there is no free optical line at the present time, and transmits the fact to the terminal 4 b, and The transmission of the frame data F1b from 4b is stopped. Thereafter, at the time when the optical line is vacant, the slave unit 3b sends a frame data retransmission request signal RRb to the terminal 4b.
Send.

On the other hand, an optical line use permission signal PM
The slave unit 3a that has received the frame data F1a from the terminal 4a transmits the frame data F1a to the light emitting unit as shown by T4a in FIG. , The optical preamble signal P and the frame data F1a as indicated by T5a in FIG.
To transmit light. The master unit 1 transmits the frame data F1a sent from the slave unit 3a to the network trunk line 2 by wire as indicated by T6a in the figure.

Next, the frame data F1 from the slave unit 3a
After receiving a and transmitting it to the network trunk 2,
Open the optical line to all the slaves 3 once, and
An optical line free signal SP is transmitted as shown in FIG. 1, and within a certain time, it waits for an optical line use request signal RE to be sent from any of the slaves 3. Here, if the optical line use request signal RE is not sent from any of the slave units 3 after a certain time has elapsed after the transmission of the optical line idle signal SP as indicated by T11 in the figure, the master unit 1 Transmits an optical line use permission signal PMa to the slave unit 3a which issued the use permission of the optical line immediately before (last) as shown in T13a in the figure, and the slave unit 3a transmits the frame data. Wait for a certain time to come.

The optical line free signal SP optically transmitted from the master unit 1 as indicated by T11 in the figure and the optical line use permission signal PMa for the slave unit 3a are the slave units other than the slave unit 3a (for example, the slave unit 3b). Also received. At this time, before the slave unit 3b optically transmits the optical line use request signal REb to the master unit 1, the slave unit 3a sends the optical line use permission signal to the master unit 1 as indicated by T13a in the drawing. When the PMa is transmitted, the child device 3b recognizes that there is no free optical line at this time.

On the other hand, the slave unit 3a, which has received the optical line use permission signal PMa by T13a in the figure from the master unit 1, can transmit the next frame data F2a within a certain time, or can send the next frame data within a certain time. When it becomes necessary to transmit the data F2, the frame data F from the terminal 4a is transmitted.
2a is transmitted by wire to a light emitting unit as indicated by T14a in the figure, and the light emitting unit optically transmits the optical preamble signal P and the frame data F2a to the master unit 1 as indicated by T15a in the figure. The parent device 1 transmits the frame data F2a sent from the child device 3a to the network trunk line 2 by wire, as indicated by T16a in the figure.

Next, the frame data F2 from the slave unit 3a
After receiving a, the master unit 1 once releases the optical line to all the slave units 3, and transmits the optical line idle signal SP as indicated by T21 in the figure. Here, as shown at T21 in FIG.
If the optical line use request signal RE is not sent from any of the slave units 3 even after a certain period of time has elapsed after transmitting P,
The master unit 1 transmits the optical line use permission signal PMa to the slave unit 3a that issued the use permission of the optical line immediately before (the last). For example, as shown in T2b in FIG. Before a predetermined time has elapsed from the transmission of the signal SP (within a predetermined time), for example, the optical line use request signal RE
When b is sent, the master unit 1 transmits the optical preamble signal P and the optical line use permission signal PMb to the slave unit 3b as indicated by T3b in the figure.

The slave unit 3b, which has received the optical line use permission signal PMb from the master unit 1 by T3b in the figure, transmits the frame data F1b from the terminal 4b as shown in T4b in FIG. Then, the optical preamble signal P and the frame data F1b are optically transmitted from the light emitting unit to the master unit 1 as indicated by T5b in the figure. The master unit 1 transmits the frame data F1b sent from the slave unit 3b to the network trunk line 2 by wire, as indicated by T6b in the figure.

Next, the frame data F1 from the slave unit 3b
After receiving b, the master unit 1 once releases the optical line to all the slave units 3, and transmits the optical line idle signal SP as indicated by T31 in the figure. Here, as shown at T31 in FIG.
If the optical line use request signal RE is not sent from any of the slave units 3 even after a certain period of time has elapsed after transmitting P,
The master unit 1 transmits an optical line use permission signal PMb to the slave unit 3b that issued the use permission of the optical line immediately before (last), as indicated by T13b in the figure. When the optical line use request signal RE is sent from another slave unit 3 before the time elapses (within a predetermined time), the base unit 1 sends the optical line use permission signal PM to the other slave unit 3. Will be sent. The following description is omitted because it is the same as the above.

FIGS. 2 and 3 show that the master unit 1 transmits the signal transmitted in frame units from the slave unit 3 to the slave unit 3.
3 shows a signal transmission / reception timing image in a case where a function of transmitting back to the slave unit 3 is not provided, but a function of returning a signal in a frame unit transmitted from the slave unit 3 to the slave unit 3 is provided. FIG. 4 shows a basic signal transmission / reception timing image in the optical wireless communication system in the case where the optical communication system 1 is provided.

In FIG. 4, for example, when transmitting the frame data F1 generated by the terminal 4 from the slave unit 3 to the master unit 1, first, the optical line optically transmitted from the master unit 1 as indicated by T1 in the figure. The slave unit 3 that has detected (received) the empty signal SP
The optical preamble signal P is transmitted to the base unit 1 as indicated by T2 in the figure.
And optically transmits an optical line use request signal RE. When receiving the optical line use request signal RE, the master unit 1 transmits an optical preamble signal P and an optical line use permission signal PM to the slave unit 3 as indicated by T3 in the figure when the optical line can be used. And waits for a certain period of time for the frame data to be transmitted from the child device 3. Optical line use permission signal PM from master unit 1
Receives the frame data F within a predetermined time.
1 can be transmitted, the frame data F1
Is transmitted to the light-emitting unit by wire as indicated by T4 in the figure, and the light-emitting unit optically transmits the optical preamble signal P and the frame data F1 to the master unit 1 as indicated by T5 in the figure. Base unit 1
Transmits the frame data F1 sent from the slave unit 3 to the network trunk line 2 by wire as indicated by T6 in the figure.

Although not shown in FIG. 4, the optical line free signal SP and the optical line use permission signal PM optically transmitted from the master unit 1 as indicated by T1 in FIG. The other handset recognizes that there is no free optical line at this time.

Up to this point, it is the same as FIG. 2, but in the case of FIG. 4, the master unit 1 sends frame data F1 received by the light receiving unit and transmitted to the network trunk line 2 to the light emitting unit as T7 in the figure. Further, as shown at T8 in FIG. The slave unit 3 that has received the frame data F1 that has been transmitted back from the master unit 1 by optical transmission transmits the frame data F1 to the terminal 4 by wire as indicated by T9 in the figure. Thus, the terminal 4 knows that the frame data has been transmitted normally.

Next, the frame data F generated by the terminal 4
When transmitting the second frame data from the slave unit 3 to the master unit 1, the master unit 1 returns the frame data F1 to the slave unit 3 and then transmits the frame data F1 to the slave unit 3 and then temporarily releases the optical line to all slave units 3, and As shown in the middle T11, the optical line free signal SP is transmitted, and a predetermined time is waited. Here, if the optical line use request signal RE is not sent from any of the slave units 3 after a certain time has elapsed after the transmission of the optical line idle signal SP as indicated by T11 in the figure, the master unit 1 Transmits an optical line use permission signal PM to the slave unit 3 which has issued the use permission of the optical line immediately before (last), as indicated by T13 in the figure, and waits for a further fixed time.

The optical line free signal SP and the optical line use permission signal PM for the child device 3 optically transmitted from the parent device 1 as indicated by T11 in the figure are also received by other child devices other than the child device 3. The other handset recognizes that there is no free optical line at this time.

The slave unit 3 which has received the optical line use permission signal PM by T13 in the figure from the master unit 1 can transmit the next frame data F2 within a certain time, or can send the next frame data F2 within a certain time. When it is necessary to transmit the frame data F2 from the terminal 4 to the light emitting unit as shown by T14 in the figure, and further, the light emitting unit transmits the optical preamble signal to the base unit 1 as shown by T15 in the figure. P and frame data F2 are optically transmitted. Base unit 1 is slave unit 3
The frame data F2 sent from is transmitted by wire to the network trunk line 2 as indicated by T16 in the figure, and the frame data F2 is transmitted to the light emitting unit as T17 in the figure,
Further, as shown at T18 in the figure, the optical signal is transmitted back to the slave unit 3. The slave unit 3 that has received the frame data F2 transmitted back from the master unit 1 by the light
2 is transmitted to the terminal 4 by wire as indicated by T19 in the figure.

When the terminal 4 transmits the generated frame data F3 from the slave unit 3 to the master unit 1, the master unit 1 returns the previous frame data F2 to the slave unit 3 and then transmits the frame data F3. Then, the optical line is released to all the slave units 3, and the optical line idle signal SP is transmitted as indicated by T21 in the figure.
If E is not sent, an optical line use permission signal PM is transmitted to the handset 3 that issued the use permission of the optical line immediately before, as indicated by T23 in the figure.

The slave unit 3 which has received the optical line use permission signal PM by T23 in the figure from the master unit 1 can transmit the next frame data F3 within a certain time, or can send the next frame data F3 within a certain time. When it is necessary to transmit the frame data F3 from the terminal 4, the frame data F3 is transmitted by wire to the light emitting unit as indicated by T24 in the figure, and the light emitting unit transmits an optical preamble signal to the base unit 1 as indicated by T25 in the figure. P and frame data F3 are optically transmitted. Base unit 1 is slave unit 3
As shown in T16 in the figure, the frame data F3 sent from is transmitted by wire to the network trunk line 2, and the frame data F3 is transmitted back to the slave unit 3 via the light emitting unit. The slave 3 that has received the frame data F3 that is transmitted back from the master 1 by light transmits the frame data F3 to the terminal 4 by wire.

Although the basic operation has been described with reference to FIG. 4 without specifying a slave, a plurality of slaves 3a, 3b, 3c are each capable of optically communicating with the master 1. If
It goes without saying that a procedure similar to that of FIG. 3 described above is employed.

In FIGS. 2 to 4 described above, the frame data received from the terminal 4 is sent from the slave unit 3 to the master unit 1,
Further, an example in which the frame is sent from the base unit 1 to the network trunk line 2 has been described. The reverse is true, that is, the frame data received from the network trunk line 2 is sent from the base unit 1 to the slave unit 3 and further from the slave unit 3 to the terminal 4 Basically, the same procedure as described above is taken.

As described above with reference to FIGS.
According to the optical wireless communication system of the present invention, the slave 3 is connected to the terminal 4
When transmitting the frame data received from the
First, when the optical line free signal SP is detected, an optical line use request signal RE is transmitted to the base unit 1, and correspondingly, when receiving the optical line use permission signal PM from the base unit 1, frame data is transmitted. . Thereafter, when the slave unit 3 receives the optical line use permission signal PM sent from the master unit 1, if the next frame data from the terminal 4 can be transmitted within a predetermined time,
Alternatively, if it becomes necessary to transmit the next frame data within a certain time, the frame data is transmitted without a communication procedure such as the transmission of the previous line request signal RE.

Next, a transmission / reception timing image in which the frame data is not looped back as shown in FIG. 3 (or the master unit 1 does not have the looping function) is realized.
FIG. 5 shows a configuration of a specific example of the master unit 1 of the optical wireless communication system of FIG.
Shown in

In master unit 1 shown in FIG.
1 controls the overall operation of the master unit 1, controls communication with the network trunk 2, and controls half-duplex optical communication with the slave unit 3. A detailed control operation flow in the control unit 51 will be described later.

The base unit 1 has a light emitting unit 67 for outputting light over a wide range and a transmission signal for performing optical communication, as a configuration for performing wireless communication with the slave unit 3 using light. An optical transmission processing unit 66 that drives the light emitting unit 67, a light receiving unit 60 that receives light from a wide range, and an optical reception processing unit 59 that extracts a signal transmitted by optical communication from a light receiving signal of the light receiving unit 60. Have.

The reception signal output from the optical reception processing section 59 is transmitted to a line request signal recording section 58 and a line request signal detection section 5.
7, the line request unit 56, the transmission data detection unit 55, and the trunk transmission switching unit 53.

The line request signal detecting section 57 detects the above-mentioned optical line use request signal RE transmitted from each of the slave units 3 among the received signals from the optical reception processing section 59. When the line request signal detection section 57 detects the optical line use request signal RE, the detection signal is sent to the control section 51.

When the line request signal detecting section 57 detects the optical line use request signal RE, the line request signal recording section 58 controls the optical line use request signal R under the control of the control section 51.
Record E. Specifically, the slave unit number included in the optical line use request signal RE (for example, an ID unique to the slave unit)
Record The slave unit number recorded in the line request signal recording unit 58 is read under the control of the control unit 51,
The signal is sent to the optical line use permission signal generator 61.

Under the control of the control unit 51, the optical line use permission signal generating unit 61 sends the sub unit of the sub unit number supplied from the line request signal recording unit 58, that is, the sub unit which has issued the line use request. On the other hand, when the use of the optical line is permitted, an optical line use permission signal PM transmitted to the slave unit is generated. The optical line use permission signal PM is transmitted to the optical transmission switch 62
Sent to

Under the control of the control unit 51, the line free signal generating unit 65 generates the above-mentioned optical line free signal SP and sends the optical line free signal SP to the optical transmission switching unit 62.

The optical preamble generating section 64 generates the optical preamble signal P to be added to the signal transmitted to the slave unit 3 and sends the optical preamble signal P to the optical transmission switching section 62.

Further, the trunk line signal receiving section 68 sends a signal from the signal on the network trunk line 2 to each terminal 4 included in the optical wireless communication system of FIG. The transmitted signal is received, and the received signal is transmitted to the transmission data detection unit 63 and the optical transmission switching unit 62.

The transmission data detecting section 63 transmits the transmission data (actually, each terminal 4 connected to each child apparatus 3) from the received signal from the trunk signal receiving section 68 to each of the child apparatuses (actually, each terminal 4 connected to each child apparatus 3). Frame data), and outputs the detection signal to the control unit 5.
Send to 1.

Under the control of the control section 51, the optical transmission switching section 62 controls the optical line use permission signal PM and the optical line idle signal S
P, the optical preamble signal P, and the frame data transmitted to the terminal 4 via the network trunk 2 are switched according to the respective transmission timings, and the switched signal is transmitted to the optical transmission processing unit 66.

The optical transmission processing section 66 drives the light emitting section 67 according to the transmission signal supplied from the optical transmission switching section 62.
As a result, the light emitting section 67 outputs an optical signal corresponding to the transmission signal.

On the other hand, the line requesting unit 56
When transmitting a reception signal from the network trunk 9 to another device connected via the network trunk 2, the network trunk 2
A line request signal for requesting transmission to the
To the main line transmission switching unit 53 via

The pseudo signal generating section 52 includes a control section 51
When the line request signal generated by the line request unit 56 is transmitted to the network trunk 2 under the control of the above, a pseudo frame used to stop signal transmission from the network trunk 2 is generated, and the trunk transmission is performed. This is sent to the switching unit 53.

Further, the transmission data detection unit 55 detects the terminal 4 (the slave unit 3) from the reception signal from the optical reception processing unit 59.
Frame data sent from
Is transmitted to the control unit 51.

Under the control of the control unit 51, the trunk transmission switching unit 53 switches a pseudo frame or frame data at each transmission timing, and sends the switched signal to the trunk transmission processing unit 54.

The main line transmission processing unit 54 includes a main line transmission switching unit 5
3 is processed into a signal that can be transmitted to the network trunk 2, and transmitted to the network trunk 2.

Next, a transmission / reception timing image for performing frame folding as shown in FIG. 4 is realized.
FIG. 6 shows a configuration of a specific example of the master unit 1 of the optical wireless communication system of FIG.
Shown in

In the components of the parent machine 1 shown in FIG. 6, the same components as those in FIG. 5 are denoted by the same reference numerals, and the description thereof will be omitted.

In FIG. 6, the received signal output from the optical reception processing unit 59 is, as in the configuration of FIG. 5, a line request signal recording unit 58, a line request signal detection unit 57, a line request unit 56, a transmission data The signals are input to the detection unit 55 and the trunk line transmission switching unit 53, and are also input to the data recording unit 69 and the optical return control unit 70.

The data recording section 69 records the frame data from the optical reception processing section 59 under the control of the control section 51.

Further, the optical turn-back control unit 70 includes the control unit 5
Under the control of 1, the frame data read from the data recording unit 69 is sent to the optical transmission switching unit 62 as a return frame.

Under the control of the control unit 51, the optical transmission switching unit 62 controls the optical line use permission signal PM, the optical line idle signal SP, the optical preamble signal P, the network trunk line 2
Frame data sent to the terminal 4 via
The return frame data from the optical return control unit 69 is switched according to the respective transmission timings, and the signal after the switch is sent to the optical transmission processing unit 66.

As a result, the light emitting section 67 outputs an optical signal (including a folded frame) corresponding to the transmission signal.

Next, FIG. 7 shows a configuration of a specific example of the slave unit 3 of the optical wireless communication system of FIG. 1 for realizing the transmission / reception timing images of FIGS.

In the slave unit 3 shown in FIG.
Reference numeral 1 controls the overall operation of the slave unit 3 and controls communication with the terminal 4 and half-duplex optical communication with the master unit 1. The detailed flow of the control operation of the control unit 81 will be described later.

The slave unit 3 has a configuration for performing wireless communication with the master unit 1 by light, and includes a light emitting unit 97 for outputting a narrow-angle beam light and a transmission signal for optical communication. An optical transmission processing unit 96 for driving the light emitting unit 97 in response to the light receiving unit 90; a light receiving unit 90 for receiving the signal light at a narrow angle;
And an optical reception processing unit 89 for extracting a signal transmitted by optical communication from the received light signal.

The received signal output by the optical reception processing unit 89 is transmitted to an optical line use permission signal recording unit 88, an optical line use permission signal detection unit 91, a line free signal detection unit 95, a line request unit 86, The data is input to the transmission data detection unit 85 and the terminal transmission switching unit 83.

The optical line use permission signal detecting section 91 detects the above-mentioned optical line use permission signal PM transmitted from the master unit 1 among the received signals from the optical reception processing section 89. When the optical line use permission signal detection section 91 detects the optical line use permission signal PM, the detection signal is sent to the control section 81.

When the optical line use permission signal detecting section 91 detects the optical line use permission signal PM, the optical line use permission signal recording section 88 controls the optical line use permission signal under the control of the control section 81. Record the PM. The optical line use permission signal PM recorded in the optical line use permission signal recording section 88 is read out under the control of the control section 81 and sent to the control section 81.

[0092] Line free signal detection section 95 detects the above-mentioned optical line free signal SP transmitted from master unit 1 among the received signals from optical reception processing section 89. When the free line signal SP is detected by the free line signal detection unit 95, the detection signal is sent to the control unit 81.

Next, the line request unit 86
When transmitting the reception signal from the terminal 9 to the terminal 4,
The control unit 81 generates a line request signal requesting transmission to the
Via the terminal transmission switching unit 83.

Further, the transmission data detecting section 85 detects the frame data addressed to the terminal 4 transmitted via the network trunk 2 and further via the base unit 1, and sends a detection signal to the control section 81.

Further, the pseudo signal generating section 82 includes a control section 81
Generates a pseudo frame used to stop signal transmission from the terminal 4 when the line request signal generated by the line request unit 86 is transmitted to the terminal 4 under the control of
This is sent to the terminal transmission switching unit 83.

Under the control of the control unit 81, the terminal transmission switching unit 83 switches a pseudo frame or frame data addressed to the terminal 4 at each transmission timing, and sends the switched signal to the terminal transmission processing unit 84. .

The terminal transmission processing section 84 includes the terminal transmission switching section 8
3 is processed into a signal that can be transmitted to the terminal 4 and transmitted to the terminal 4.

On the other hand, terminal signal receiving section 98 receives a signal transmitted from terminal 4 and transmits the received signal to line request detecting section 100, transmission data detecting section 93, data recording section 99.
Send to

Line request detecting section 100 detects a line request signal for requesting a wired communication line with handset 3 from among the signals received from terminal signal receiving section 98. When the line request detection section 100 detects a line request signal, the detection signal is sent to the control section 81.

The transmission data detection unit 93 determines the master 1 (actually, another device connected to the network trunk 2 via the master 1) based on the received signal from the terminal signal receiver 98.
, And sends a detection signal to the control unit 81.

The data recording unit 99 records the frame data sent from the terminal 4 and then sends it to the optical transmission switching unit 92 under the control of the control unit 81.

The optical preamble generating section 94 generates the optical preamble signal P under the control of the control section 81 and sends it to the optical transmission switching section 92.

Further, under the control of the control unit 81, the line request signal generating unit 87 generates an optical line use request signal RE for requesting an optical communication line with the master unit 1, and the optical transmission switching unit 9
Send to 2.

Under the control of the control unit 81, the optical transmission switching unit 92 transmits the optical line use request signal RE, the optical preamble signal P, and the frame data transmitted from the terminal 4 to the network trunk 2, respectively. Switching is performed according to the timing, and the signal after the switching is sent to the optical transmission processing unit 96.

The optical transmission processing section 96 drives the light emitting section 97 according to the transmission signal supplied from the optical transmission switching section 92.
Thus, the light emitting section 97 outputs an optical signal corresponding to the transmission signal.

Next, in the case where the communication procedure as described in the transmission / reception timing images of FIGS. 2 to 4 is realized in the above-described master unit having the configuration of FIGS. 5 and 6 and the slave unit 3 having the configuration of FIG. The flow of the process will be described.

First, FIG. 8 shows the flow of processing in the base unit 1 from reception of frame data sent via the network trunk 2 to transmission to the slave unit 3 (mainly the control of the control unit 51). Operation flow) is shown.

In FIG. 8, first, the control unit 51 of the base unit 1 monitors whether or not optical communication with the slave unit 3 is being performed as a process of step S1, thereby connecting to the optical line. It is determined whether or not there is a vacancy, and when there is no vacancy in the optical line, as a process in step S2, the pseudo signal generation unit 52 is controlled to generate a pseudo frame signal. By controlling the switching of 53, the pseudo frame is transmitted to the network trunk 2, and the signal transmission from the network trunk 2 is stopped. On the other hand, when there is an empty optical line, the control unit 51 performs the generation of the pseudo frame from the pseudo signal generation unit 52 and the switching control of the trunk transmission switching unit 53 as the processing of step S3, so that the network trunk 2 Stop sending pseudo frames to

Next, the control unit 51 checks whether or not frame data has been transmitted from the network trunk 2 by monitoring the detection signal of the transmission data detection unit 63 as the process of step S4. In the process of step S4, when frame data has not been transmitted, the process returns to step S1.
When the frame data is detected, the process proceeds to step S5.

When the process proceeds to step S5, the control unit 51
Stops transmission of the optical line release signal, that is, controls the above-mentioned line empty signal generation unit 65 to transmit the optical line empty signal SP.
Is stopped, and by controlling the optical transmission switching unit 62, the transmission of the optical line idle signal SP is stopped.

Next, as the processing of step S6, the control section 51 sends the data from the network trunk 2 to a memory (not shown) such as a FIFO (first-in first-out) provided with the optical transmission switching section 62, for example. By recording the received frame data, the frame data is
The frame data is delayed until the transmission becomes possible.

Next, the control section 51 controls the optical preamble generating section 64 to generate the optical preamble signal P as the processing of step S7, and further controls the switching of the optical transmission switching section 62 as the processing of step S8. By transmitting the optical preamble signal P to the optical transmission processing unit 66, the optical preamble signal P is transmitted to the slave unit 3 (light emission of the light emitting unit 67).
I do.

Subsequently, the control section 51 reads out, for example, frame data recorded in a memory associated with the optical transmission switching section 62 as a process of step S9, and further switches the optical transmission switching section 62. By transmitting the frame data to the optical transmission processing unit 66 under the control, the frame data is transmitted to the slave unit 3 (light emission of the light emitting unit 67).

Next, in step S10, the control unit 51 determines whether or not all the frame data recorded in the memory has been read and transmitted. If the reading and transmission have not been completed, the control unit 51 proceeds to step S9. Returning, when the reading and transmission are completed, the process proceeds to step S11.

When the process proceeds to step S11, the control unit 5
1 stops reading and transmitting from the memory.

After that, the control unit 51 restarts the transmission of the optical line release signal as the process of step S12,
By controlling the line free signal generator 65, the optical line free signal SP
Is generated, and the optical transmission switching unit 62 is controlled to transmit the optical line idle signal SP. Then, the process returns to step S1.

Next, FIG. 9 shows a process of receiving an optical frame signal from the handset 3 and transmitting it to the network trunk 2.
The process flow (mainly control unit 51) in master device 1 shown in FIG. 5 corresponding to the transmission / reception timing image in FIG.
Is shown.

In FIG. 9, first, the control unit 51 of the master unit 1 determines whether or not there is a transmission request signal from the slave unit 3, that is, the line request signal detection unit 5 in step S21.
7, by monitoring whether or not the optical line use request signal RE from the slave unit 3 is detected, it is determined whether or not the slave unit 3 is requesting transmission using the optical line.
When the line request signal detection unit 57 detects the optical line use request signal RE, the process proceeds to step S22.

At step S22, the control unit 5
1 stops transmission of the optical line release signal, that is, controls the line idle signal generation unit 65 to stop the generation of the optical line idle signal SP, and controls the optical transmission switching unit 62 to control the optical line open signal. The transmission of the empty signal SP is stopped.

Next, the control unit 51 transmits the optical preamble signal P and the optical line use permission signal PM to the slave unit 3 as the process of step S23. That is, the optical preamble generator 64 is controlled to generate the optical preamble signal P, and the optical line use permission signal generator 61 is controlled to generate the optical line use permission signal PM. By transmitting the line use permission signal PM to the optical transmission processing unit 66 by the switching control of the optical transmission switching unit 62, the optical preamble signal P and the optical line use permission signal PM
Is transmitted to the slave unit 3 (light emission of the light emitting unit 67).

Next, as the process of step S24, the control unit 51 monitors the detection signal of the transmission data detection unit 55 to determine whether or not frame data has been transmitted from the slave unit 3.

Here, when the frame data has not been transmitted, the control unit 51 further determines whether or not the state has passed for a certain period of time in the process of step S25. Step S
The determination process of 25 is continued.

On the other hand, if the frame data has not been transmitted even after the elapse of the predetermined time in step S25,
1 controls the line idle signal generator 65 to generate an optical line idle signal as the process of step S29,
By controlling the optical transmission switching unit 62, the optical line idle signal SP
Resume sending. After the process in step S29, the process ends or returns to the process in step S21.

On the other hand, when it is determined in the determination processing in steps S24 and S25 that frame data has been transmitted from the slave unit 3 within a predetermined time, the control unit 51
The main line transmission switching unit 53
And the frame data is transferred to the trunk transmission processing unit 5.
4 to the network trunk 2.

Next, the control unit 51 determines whether or not the transmission of the frame data from the slave unit 3 to the network trunk 2 has been completed as the process of step S27. If the transmission has not been completed, the control unit 51 proceeds to step S26. Returning to the process, when the transmission is completed, the process proceeds to step S28.

When the process proceeds to step S28, the control unit 5
1 transmits the optical preamble signal P and the optical line use permission signal PM to the child device 3 that has transmitted last (the terminal device that has finally been given the optical line use permission). That is, the optical preamble generator 64 is controlled to generate the optical preamble signal P, and the optical line use permission signal generator 61 is controlled to generate the optical line use permission signal PM. By transmitting the line use permission signal PM to the optical transmission processing unit 66 by the switching control of the optical transmission switching unit 62, the optical preamble signal P and the optical line use permission signal PM
Is transmitted to the slave unit 3 (light emission of the light emitting unit 67). Thereafter, the process returns to step S24.

Next, FIG. 10 shows the parent frame shown in FIG. 5 corresponding to the transmission / reception timing image of FIG. 3 described above, from reception of the optical frame signal from the slave unit 3 to transmission to the network trunk 2. 3 shows a flow of processing in the machine 1 (mainly a flow of a control operation of the control unit 51).

In FIG. 10, first, the control unit 51 of the base unit 1 executes the processing of step S31, in which the line request signal detecting unit 57 outputs the optical line use request signal R
By monitoring whether or not E has been detected, it is determined whether or not the handset 3 has requested transmission using an optical line. When the RE is detected, the process proceeds to a step S32.

When the processing proceeds to step S32, the control unit 5
1 controls the line free signal generation unit 65 to stop the generation of the optical line free signal SP, and controls the optical transmission switching unit 62 to stop the transmission of the optical line free signal SP.

Next, the control section 51 controls the optical preamble generating section 64 to generate the optical preamble signal P, and controls the optical line use permission signal generating section 61 to control the optical line A use permission signal PM is generated, and the optical preamble signal P and the optical line use permission signal PM are transmitted to the optical transmission processing unit 66 by the switching control of the optical transmission switching unit 62. Transmits signal PM to handset 3 (light emission of light emitting section 67)
I do.

Next, as the process of step S34, the control unit 51 monitors the detection signal of the transmission data detection unit 55 to determine whether or not frame data has been transmitted from the slave unit 3.

Here, when the frame data has not been transmitted, the control section 51 further determines whether or not the state has passed for a certain period of time as the processing of step S35. Step S
The determination processing of 35 is continued.

On the other hand, if the frame data has not been transmitted even after the elapse of the predetermined time in step S35, the control unit 5
1 controls the line vacancy signal generation unit 65 to generate an optical line vacancy signal as the process of step S36,
By controlling the optical transmission switching unit 62, the optical line idle signal SP
Resume sending. After the process in step S36, the process ends or the process returns to step S31.

On the other hand, when it is determined in the determination processing in steps S34 and S35 that frame data has been transmitted from the slave unit 3 within a predetermined time, the control unit 51
The main line transmission switching unit 53
And the frame data is transferred to the trunk transmission processing unit 5.
4 to the network trunk 2.

Next, as the processing of step S38, the control unit 51 determines whether or not the transmission of the frame data from the slave unit 3 to the network trunk 2 has been completed. If the transmission has not been completed, the control unit 51 proceeds to step S37. Returning to the processing, when the transmission is completed, the processing proceeds to the processing in step S39.

When the process proceeds to step S39, the control unit 5
1 controls the line free signal generation unit 65 to generate the optical line free signal SP, and controls the optical transmission switching unit 62 to transmit the optical line free signal SP.

Next, as the process of step S40, the control unit 51 monitors the detection signal of the line request signal detection unit 57 to determine whether or not the optical line use request signal RE from the slave unit 3 has been detected. I do.

Here, an optical line use request signal R
When E is not transmitted, the control unit 51 further determines whether or not the state has passed for a predetermined time as the processing of step S41, and continues the determination processing of steps S40 and S41 until the predetermined time has elapsed. .

On the other hand, if the optical line use request signal RE has not been transmitted even after the lapse of a certain time in step S40,
The control unit 51 controls the optical preamble generation unit 64 and the optical line use permission signal generation unit 61 as the process of step S42, so that the slave unit that has transmitted last (the slave unit that has given the optical line use permission last) 3), transmits an optical preamble signal P and an optical line use permission signal PM. After the process in step S42, the process returns to step S34.

On the other hand, if it is determined in the determination processing in steps S40 and S41 that the optical line use request signal RE has been transmitted from the slave unit 3 within a predetermined time, the control unit 51 proceeds to the processing in step S32. Return.

Next, FIG. 11 shows the frame shown in FIG. 6 corresponding to the transmission / reception timing image of FIG. 4 described above, from the reception of the optical frame signal from the slave unit 3 to the transmission to the network trunk 2. 4 shows a flow of processing (mainly a flow of a control operation of the control unit 51) in the parent device 1 that performs the return.

In FIG. 11, first, the control unit 51 of the base unit 1 monitors whether or not the line request signal detection unit 57 has detected the optical line use request signal RE as the process of step S51, and When the request signal detection unit 57 detects the optical line use request signal RE, the process proceeds to step S52.

When the process proceeds to step S52, the control unit 5
1 controls the line free signal generation unit 65 to stop the generation of the optical line free signal SP, and controls the optical transmission switching unit 62 to stop the transmission of the optical line free signal SP.

Next, as the process of step S53, the control unit 51 controls the optical preamble generating unit 64 and the optical line use permission signal generating unit 61 to generate the optical preamble signal P and the optical line use permission signal PM. Further, the optical transmission switching unit 62 is switch-controlled to transmit the optical preamble signal P and the optical line use permission signal PM to the slave unit 3 (light emission of the light emitting unit 67).

Next, the control unit 51 determines whether or not frame data has been transmitted from the slave unit 3 by monitoring the detection signal of the transmission data detection unit 55 as the process of step S54.

Here, when the frame data has not been transmitted, the control section 51 further determines whether or not the state has passed for a predetermined time as the processing of step S55. Step S
The determination processing of 55 is continued.

On the other hand, if the frame data has not been transmitted even after the elapse of the predetermined time in step S55, the control unit 5
The control unit 1 controls the line idle signal generation unit 65 and the optical transmission switching unit 62 to restart the transmission of the optical line idle signal SP as the process of step S56. After the process in step S56, the process ends or the process returns to step S51.

On the other hand, if it is determined in step S54 and step S55 that frame data has been transmitted from the slave unit 3 within a certain period of time, the control unit 51
Records the frame data in the memory constituting the data recording unit 69 as the process of step S57, and performs the main line transmission switching unit 53 as the process of step S58.
, The frame data from the slave unit 3 is transmitted to the trunk transmission processing unit 54 and transmitted to the network trunk 2.

Next, the control unit 51 determines whether or not the transmission of the frame data from the slave unit 3 to the network trunk 2 has been completed as the process of step S59. If the transmission has not been completed, the control unit 51 proceeds to step S57. Returning to the process, when the transmission is completed, the process proceeds to step S60.

At step S60, the control unit 5
1 is a data recording unit 6 via the optical turn-back control unit 70.
9, the optical preamble generating section 64 and the optical transmission switching section 62 are controlled to return the optical preamble signal P and the frame data for return transmission to the slave unit 3.

Next, as the processing of step S61, the control unit 51 determines whether or not the transmission of the return frame data to the slave unit 3 has been completed. If the transmission has not been completed, the control unit 51 returns to the processing of step S60. When the transmission has been completed, the process proceeds to step S62.

When the process proceeds to step S62, the control unit 5
1 controls the line free signal generation unit 65 to generate the optical line free signal SP, and controls the optical transmission switching unit 62 to transmit the optical line free signal SP.

Next, the control unit 51 determines whether or not the optical line use request signal RE from the slave unit 3 has been detected by monitoring the detection signal of the line request signal detection unit 57 as the process of step S63. I do.

Here, an optical line use request signal R
When E has not been transmitted, the control unit 51 further determines whether or not the state has elapsed for a predetermined time as the processing of step S64, and continues the determination processing of steps S63 and S64 until the predetermined time has elapsed. .

On the other hand, if the optical line use request signal RE has not been transmitted after the elapse of a certain time in step S64,
The control unit 51 controls the optical preamble generation unit 64 and the optical line use permission signal generation unit 61 as the process of step S65, and sends the optical preamble signal P and the optical preamble signal A line use permission signal PM is transmitted. After the processing in step S65, step S54
Return to the processing of.

On the other hand, when it is determined in the determination processing in steps S63 and S64 that the optical line use request signal RE has been transmitted from the slave unit 3 within a predetermined time, the control unit 51 proceeds to the processing in step S52. Return.

Next, FIG. 12 shows the above-described FIG. 2 from reception of the optical frame signal from the base unit 1 to transmission to the terminal 4.
7 corresponding to the transmission / reception timing image of FIG.
9 shows the flow of processing (mainly the flow of the control operation of the control unit 81) in the slave unit 3 shown in FIG.

In FIG. 12, first, the control unit 81 of the slave unit 1 monitors the detection operation of the transmission data detection unit 85 as the process of step S71, so that the optical frame data is transmitted from the master unit 1. Has been determined. In step S71, the transmission data detection unit 8
5 when the frame data from the master unit 1 is detected,
Proceed to step S72.

At step S72, the control unit 81
The optical line use permission obtained from the master unit 1 is set to off (the optical line use permission flag is turned off), and then, step S73.
In the process of (1), the pseudo signal generation unit 82 is controlled to generate a pseudo frame, and the terminal transmission switching unit 83 is switched and controlled so that the pseudo frame is transmitted to the terminal 4. Stop.

Next, the control unit 81 stores the master unit 1 in a memory (not shown) such as a FIFO provided with the terminal transmission switching unit 83, for example, as a process of step S74.
By recording the frame data sent from the terminal 4, the frame data is delayed until the frame data can be transmitted to the terminal 4.

Next, the control section 81 reads out the frame data recorded in the memory attached to the terminal transmission switching section 83 as the processing of step S75, and further switches the terminal transmission switching section 83. Under the control, the frame data is transmitted to the terminal 4 by transmitting the frame data to the terminal transmission processing unit 84.

Next, in step S76, the control section 81 determines whether or not all the frame data recorded in the memory has been read and transmitted. If the reading and transmission have not been completed, the control section 81 proceeds to step S75. Returning, when the reading and the transmission are completed, the process proceeds to step S77.

When the process proceeds to step S77, the control unit 8
1 stops reading and transmitting from the memory. Thereafter, the process returns to step S71.

Next, FIG. 13 shows the above-described FIG. 4 from reception of an optical frame signal from the base unit 1 to transmission to the terminal 4.
8 shows a flow of processing (mainly a flow of a control operation of the control unit 81) in the slave unit 3 shown in FIG.

In FIG. 13, first, the control unit 81 of the slave unit 1 monitors the detection operation of the transmission data detection unit 85 as the process of step S81, so that the optical frame data is transmitted from the master unit 1. It is determined whether or not the frame data has been transmitted from the base unit 1, and the process proceeds to step S82.

At step S82, the control unit 81
It is determined whether or not the frame data transmitted from the base unit 1 is the frame data transmitted by itself to the base unit first, that is, whether the frame data is the frame data transmitted back from the base unit 1. If the frame is not a return frame, step S83
Proceed to processing.

When the process proceeds to step S83, the control unit 8
1 sets the optical line use permission obtained from the base unit 1 to off (turns off the optical line use permission flag), and then controls the pseudo signal generation unit 82 to generate a pseudo frame as the process of step S84. At the same time, the terminal transmission switching unit 83 is switched and controlled so that the pseudo frame is transmitted to the terminal 4.

Next, the control section 81 records the frame data sent from the master unit 1 in a memory provided in association with the terminal transmission The frame data is delayed until the timing at which the frame data can be transmitted to the terminal 4.

Next, the control section 81 reads out the frame data recorded in the memory as the processing of step S86, and further executes the switching control of the terminal transmission switching section 83 to transmit the frame data to the terminal transmission processing section. The data is transmitted to the terminal 4 by being transmitted to the unit 84.

Next, in step S87, the control section 81 determines whether or not all the frame data recorded in the memory has been read and transmitted. If the reading and transmission have not been completed, the control section 81 proceeds to step S86. Returning, when reading and transmission are completed, the process proceeds to step S88.

When the process proceeds to step S88, the control unit 8
1 stops reading and transmitting from the memory. Thereafter, the process returns to step S81.

Next, FIG. 14 shows the processing from the reception of the frame data from the terminal 4 to the transmission of the frame data to the base unit 1 shown in FIGS.
7 shows a flow of processing (mainly a flow of a control operation of the control unit 81) in the slave unit 3 shown in FIG. 7 corresponding to the transmission / reception timing image of FIG.

In FIG. 14, the control unit 81 of the slave unit 1 first monitors the detection operation of the transmission data detection unit 93 in step S91 to determine whether or not frame data has been transmitted from the terminal 4. Terminal 4
When the frame data from has been transmitted, the process proceeds to step S92.

At step S92, the control section 81
By recording the frame data sent from the terminal 4 in a memory such as a FIFO corresponding to the data recording unit 99, the frame data is delayed until the frame data can be transmitted to the master unit 1. .

Next, as the process of step S93, the control unit 81 determines whether or not the optical line use permission obtained from the master unit 1 is turned on (whether or not the optical line use permission flag is turned on). When the optical line use permission flag is not turned on, the process proceeds to step S94, and when the optical line use permission flag is turned on, the process proceeds to step S97.

When the process proceeds to step S94, the control unit 8
1 monitors the signal from the line free signal detection unit 95 to determine whether or not the optical line free signal SP is detected.

Here, when the optical line free signal SP is not transmitted from the base unit 1, the control unit 81 further determines whether or not the state has passed for a predetermined time as the processing of step S95. Step S9 until time elapses
4 and the determination processing of step S95 are continued.

On the other hand, if the optical line free signal SP has not been transmitted even after the elapse of a predetermined time in step S95, the control section 81 turns off the optical line use permission flag in step S99.

Next, the control unit 81 determines in step S100
In the processing of (1), the pseudo signal generation unit 82 is controlled to generate a pseudo frame, and the terminal transmission switching unit 83 is controlled to transmit the pseudo frame to the terminal 4.

Thereafter, the control unit 81 sets the data recording unit 99
After the memory is cleared, the process is terminated.

On the other hand, if it is determined in the determination processing in steps S94 and S95 that the optical line free signal SP has been transmitted from the base unit 1 within a predetermined time, the control unit 81 proceeds to the processing in step S96. move on.

When the process proceeds to step S96, the control unit 8
1 controls an optical preamble generator 94 and a line request signal generator 87 to generate an optical preamble signal P and an optical line use request signal RE, and further controls switching of an optical transmission switching unit 92 to control the optical preamble. The signal P and the optical line use request signal RE are transmitted to the base unit 1 (the light emitting unit 97 emits light).

Next, the control section 81 monitors the output of the optical line use permission signal detecting section 91 to determine whether or not the optical line use permission signal PM has been transmitted from the master unit 1 as the process of step S97. judge.

Here, an optical line use permission signal P
When M has not been transmitted, the control unit 81 further determines whether or not the state has elapsed for a predetermined time as the processing of step S98, and continues the determination processing of steps S97 and S98 until the predetermined time has elapsed. .

On the other hand, if the optical line use permission signal PM has not been transmitted even after the elapse of a certain time in step S98,
The control unit 81 proceeds to the processing after step S99 described above.

On the other hand, if it is determined in step S97 and step S98 that the optical line use permission signal PM has been transmitted from the base unit 1 within a predetermined time, the control unit 81 proceeds to step S102. Proceed to.

At step S102, the control section 81 turns on the optical line use permission flag. Then, at step S103, the control section 81 sets the optical preamble generating section 9 to ON.
4 to generate an optical preamble signal SP. Further, as a process of step S104, while reading frame data from the terminal 4 previously recorded in the memory of the data recording unit 99, the optical transmission switching unit 92 The switching control is performed, and the optical preamble signal P and the frame data are transmitted to the master unit 1 (light emission of the light emitting unit 97).

Next, at step S105, the control unit 81 determines whether or not all the frame data recorded in the memory of the data recording unit 99 has been read and transmitted. Step S10
Returning to the process of step 4, when the reading and transmission are completed, the process proceeds to the process of step S106.

When the process proceeds to step S106, the control unit 81 stops reading and transmitting data from the memory of the data recording unit 99, and ends the process.

As described above, according to the embodiment of the present invention, as shown in FIG. 2, the master unit 1 records the slave unit number of the slave unit to which the optical line use permission is finally given, as shown in FIG.
After receiving the frame from the slave unit, an optical line use permission signal PM is transmitted to the slave unit, and waiting for frame data from the slave unit to be transmitted within a certain time period. If a frame is not transmitted within the above-described configuration, a function of transmitting an optical line idle signal SP indicating the release of an optical line to other slave units (all slave units) is provided. It is possible to simplify a communication procedure for applying for a request for use of an optical preamble signal and use of an optical line and issuing a permission thereof, such as the half duplex optical communication of the 16th example,
Therefore, pressure on the optical line can be eliminated, and quick half-duplex optical communication can be realized, and communication performance can be improved.

Further, according to the present embodiment, as shown in FIG. 3, in the master unit 1, the slave unit number of the slave unit to which the optical line use permission was last given is recorded, and After receiving the frame, once, an optical line free signal SP indicating the release of the optical line to other slave units (all slave units).
And waits for a certain period of time to enter a state where it can receive the optical line use request signal RE from each of the slave units. If there is an optical line use request within a certain period of time, the slave unit is permitted to use the optical line. On the other hand, if an optical line use request is not received from any of the slave units within a certain period of time after the opening of the optical line, the optical line use permission signal PM is transmitted to the slave unit to which the use permission was last given. Further, if no frame data is transmitted from the slave unit within a certain time, a function of transmitting an optical line idle signal SP indicating that the optical line is open to other slave units (all slave units) is provided. By providing the above, FIG.
5 and the communication procedure for requesting the use of the optical line and requesting the use of the optical line such as the half-duplex optical communication in the example of FIG. 16 and simplifying the communication can be simplified, thus eliminating the pressure on the optical line. As a result, quick half-duplex optical communication can be realized, and communication performance can be improved.

[0192] The same applies to the case where the master unit 1 has a function of turning the frame from the slave unit back to the slave unit as shown in Fig. 4, and the optical line use permission is finally given. After recording the slave unit number of the slave unit, and after transmitting the return frame to this slave unit, the optical line indicating the opening of the optical line to other slave units (all the slave units) once. After transmitting the idle signal SP and waiting for a certain period of time, it enters a state where it can receive the optical line use request signal RE from each of these slaves, and if there is an optical line use request, permits the slave to use the optical line, On the other hand, if the optical line use request is not received from any of the slave units within a certain time after the opening of the optical line, the optical line use permission signal PM is transmitted to the slave unit to which use has been finally given, and The frame data is not transmitted from the slave unit within a certain time If the, by which a function of transmitting an optical line empty signal SP indicating the opening of the optical line to the other handset (all slave machine), FIGS. 15 and 1 as described above
The communication procedure for applying for the use request of the optical preamble signal and the use of the optical line and issuing the permission for the optical line such as the half duplex optical communication of the example 6 can be simplified, so that the pressure on the optical line can be eliminated, and Half-duplex optical communication can be realized,
Communication performance can be improved.

Further, according to the present embodiment, as shown in FIG. 2 or FIG. 4, when a frame from terminal 4 is sent to base unit 1, If the optical line use permission is obtained again from the master unit 1 after the transmission of the master unit 1, the function of transmitting the next frame to the master unit within a predetermined time if necessary, or After the transmission of the frame, when the return frame is sent from the master unit, the master unit 1
When the optical line use permission is obtained from, the function of transmitting the next frame to the master unit within a predetermined time as necessary is provided, so that the half-duplex It is possible to simplify the communication procedure for applying for the use of optical preamble signals and the use of optical lines and issuing permission for optical communication, thus eliminating pressure on optical lines and realizing quick half-duplex optical communication. This makes it possible to improve communication performance.

Further, according to the present embodiment, as shown in FIG. 3 or FIG. 4, when the frame from terminal 4 is After ending the transmission, the first optical line vacant signal SP transmitted from the main unit 1 is ignored, the frame transmission is forgotten at that timing, and if another sub unit can transmit, the optical line It has a function to pass the right of use to the other slave unit. On the other hand, when the other slave unit does not make an optical line use request at that time and the master unit 1 gives the optical line use permission to itself, it becomes necessary. Accordingly, a function of transmitting the next frame to the base unit 1 within a predetermined time, or when a return frame is sent from the base unit after the transmission of the frame to the base unit 1, First optical line transmitted from master unit 1 after reception Has the function of passing the authority of the optical line to the other slave if the other slave can transmit, ignoring the signal SP, and deflecting the frame transmission at that timing. The device does not make an optical line use request at that timing, and has a function of transmitting the next frame to the base unit 1 within a predetermined time if necessary when the base unit 1 gives permission to use the optical line to itself. This can simplify a communication procedure for applying for a request for use of an optical preamble signal and a use of an optical line and issuing a permission thereof, such as the half-duplex optical communication in the examples of FIGS. 15 and 16 described above.
The pressure on the optical line can be eliminated, and a quick half-duplex optical communication can be realized, and the communication performance can be improved.

Finally, the description of the above embodiment is an example of the present invention. For this reason, the present invention is not limited to the above embodiments, and various changes can be made according to the design and the like as long as the technical idea according to the present invention is not deviated. It is.

[0196]

According to the optical wireless communication apparatus of the present invention, after receiving a signal from the optical wireless communication device to which the optical line use permission is given last, the optical line use permission is finally given. An optical line use permission signal is transmitted to the optical wireless communication device, and the device waits for a certain period of time. If there is no new signal transmission from the optical wireless communication device that finally gave the optical line use permission within the certain time period, By transmitting an optical line idle signal to other optical wireless communication devices, communication procedures can be simplified,
The pressure on the optical line is eliminated, and quick half-duplex optical communication can be realized.

The optical wireless communication apparatus according to the second aspect of the present invention transmits an optical signal to a plurality of other optical wireless communication apparatuses after receiving a signal from the optical wireless communication apparatus to which the optical line use permission is finally given. When a line idle signal is transmitted and the optical line use request signal is not received from any of the plurality of other optical wireless communication devices within the fixed time period, and the optical line use permission signal is given last. When an optical line use permission signal is transmitted to the wireless communication device and the device waits for a certain period of time, and when there is no new signal transmission from the optical wireless communication device that finally gave the optical line use permission within the certain time period, a plurality of By transmitting an optical line idle signal to another optical wireless communication device, the communication procedure can be simplified, pressure on the optical line can be eliminated, and quick half-duplex optical communication can be realized.

According to the third aspect of the present invention, the optical wireless communication apparatus according to the present invention waits for a predetermined time after transmitting a signal to another optical wireless communication apparatus, and waits for another optical wireless communication apparatus within the fixed time. When the optical line use permission signal is detected, by transmitting a new signal as needed to the other optical wireless communication device, the communication procedure can be simplified, the pressure on the optical line is removed, Rapid half-duplex optical communication is feasible.

According to the fourth aspect of the present invention, an optical wireless communication apparatus according to the present invention transmits a signal to another optical wireless communication apparatus, and then transmits the first optical line transmitted from the other optical wireless communication apparatus. Ignore the vacant signal and wait for a certain period of time, and when an optical line use permission signal from another optical wireless communication device is detected within the certain time, a new By transmitting the signal, the communication procedure can be simplified, pressure on the optical line can be eliminated, and quick half-duplex optical communication can be realized.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a schematic configuration of an optical wireless communication system according to an embodiment of the present invention.

FIG. 2 is a diagram showing a basic signal transmission / reception timing image in the optical wireless communication system of FIG. 1 when transmitting a frame generated by a terminal from a slave unit to a master unit.

FIG. 3 is a diagram showing a signal transmission / reception timing image of the optical wireless communication system of FIG. 1 in a system in which each of a plurality of slave units is capable of optical communication with a master unit.

FIG. 4 is a diagram showing a signal transmission / reception timing image in the optical wireless communication system of FIG. 1 in a case where the master unit has a function of returning transmission to the slave unit.

FIG. 5 is a block diagram illustrating a configuration of a specific example of a parent device that does not perform frame return transmission.

FIG. 6 is a block diagram illustrating a configuration of a specific example of a master unit having a frame return transmission function.

FIG. 7 is a block diagram showing a configuration of a specific example of a child device.

FIG. 8 is a flowchart showing a flow of processing from reception of frame data sent via a network trunk line to transmission to a slave unit in the master unit.

FIG. 9 is a flowchart illustrating a flow of processing from reception of an optical frame signal from a child device to transmission to a network trunk in a parent device that does not perform frame return transmission.

FIG. 10 is a flowchart showing a flow of processing from reception of an optical frame signal from a slave unit to transmission to a network trunk in a master unit that does not perform frame return transmission.

FIG. 11 shows a master unit that performs frame return transmission.
It is a flowchart which shows the flow of a process until the optical frame signal from a slave unit is received and it transmits to a network trunk.

FIG. 12 is a diagram illustrating a slave unit that does not return a frame from the master unit, receives an optical frame signal from the master unit,
9 is a flowchart illustrating a flow of a process up to transmission to a terminal.

FIG. 13 is a flowchart showing a flow of processing from reception of an optical frame signal from the parent device to transmission to the terminal in the child device when frame folding is performed from the parent device.

FIG. 14 is a flowchart showing a flow of processing from reception of frame data from a terminal to transmission to a parent device in the child device 3.

FIG. 15 is a diagram illustrating an example of a signal transmission / reception timing image used to explain a disadvantage when half-duplex optical communication is employed in the optical wireless communication system.

FIG. 16 is a diagram showing another example of a signal transmission / reception timing image used to explain a disadvantage when half-duplex optical communication is adopted in the optical wireless communication system.

[Explanation of symbols]

1 ... master unit, 2 ... network trunk line, 3 (3a, 3b, 3
c) ... slave unit, 4 (4a, 4b, 4c) ... terminal, 51, 8
DESCRIPTION OF SYMBOLS 1 ... Control part, 52, 82 ... Pseudo signal generation part, 53 ... Trunk transmission switching part, 54, 84 ... Trunk transmission processing part, 55, 6
3, 85, 93 ... transmission data detecting section, 56, 86, 10
0: line request unit, 57: line request signal detection unit, 58: line request signal recording unit, 59, 89: optical reception processing unit, 60,
90 ... light receiving section, 61 ... optical line use permission signal generating section, 6
2, 92: optical transmission switching section, 64, 94: optical preamble generating section, 65: line idle signal generating section, 66, 96: optical transmission processing section, 67, 97: light emitting section, 68: trunk line receiving processing section, 69 99, a data recording unit, 70, an optical return control unit, 87, a line request signal generating unit, 88, an optical line use permission signal recording unit, 91, an optical line use permission signal detection unit, 95,
Line free signal detector

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04B 10/24 H04L 29/08

Claims (4)

[Claims] 1. An optical wireless communication device for transmitting and receiving an optical signal to and from a plurality of other optical wireless communication devices by half-duplex optical communication, wherein the line generates an optical line idle signal indicating that the optical line is open. Vacant signal generating means, optical line use request signal detecting means for detecting an optical line use request signal transmitted from the other optical wireless communication device, and one of the other optical wireless communication devices Optical line use permission signal generating means for issuing an optical line use permission signal to the device; and storage means for storing, among the plurality of other optical wireless communication devices, the optical wireless communication device to which the optical line use permission has been given last. After receiving a signal from the optical wireless communication device to which the optical line use permission was last given, transmit an optical line use permission signal to the optical wireless communication device to which the last optical line use permission was given, and wait for a predetermined time. And within a certain period of time Having transmission / reception control means for transmitting the optical line idle signal to the plurality of other optical wireless communication devices when there is no new signal transmission from the optical wireless communication device to which the optical line use permission is finally given. An optical wireless communication device characterized by the above-mentioned. 2. An optical wireless communication device for transmitting and receiving an optical signal to and from a plurality of other optical wireless communication devices by half-duplex optical communication, wherein the line generates an optical line idle signal indicating that the optical line is open. Vacant signal generating means, optical line use request signal detecting means for detecting an optical line use request signal transmitted from the other optical wireless communication device, and one of the other optical wireless communication devices Optical line use permission signal generating means for issuing an optical line use permission signal to the device; and storage means for storing, among the plurality of other optical wireless communication devices, the optical wireless communication device to which the optical line use permission has been given last. After receiving the signal from the optical wireless communication device that finally gave the optical line use permission, transmits the optical line idle signal to the plurality of other optical wireless communication devices, waits for a predetermined time, and waits for the predetermined time Within the plurality of other optical radios When no optical line use request signal is received from any of the communication devices, the optical line use permission signal is transmitted to the optical wireless communication device to which the optical line use permission was last given, and the device waits for a predetermined time, and Transmission / reception control means for transmitting the optical line idle signal to the plurality of other optical wireless communication devices when there is no new signal transmission from the optical wireless communication device to which the last optical line use permission has been given within the time. An optical wireless communication device comprising: 3. An optical wireless communication device for transmitting and receiving an optical signal to and from another optical wireless communication device by half-duplex optical communication, wherein an optical line transmitted from the other optical wireless communication device is opened. A line free signal detecting means for detecting an optical line free signal representing an optical line use request signal for issuing an optical line use request signal to the other optical wireless communication device when the optical line free signal is detected. Generating means, optical line use permission signal detecting means for detecting an optical line use permission signal transmitted from the other optical wireless communication device, and waiting for a predetermined time after transmitting a signal to the other optical wireless communication device And, when the optical line use permission signal from the other optical wireless communication device is detected within the fixed time, the other optical wireless communication device, transmission and reception control means for transmitting a new signal as needed, Characterized by having Optical wireless communication device. 4. An optical wireless communication device for transmitting and receiving an optical signal to and from another optical wireless communication device by half-duplex optical communication, wherein an optical line transmitted from the other optical wireless communication device is opened. A line free signal detecting means for detecting an optical line free signal representing an optical line use request signal for issuing an optical line use request signal to the other optical wireless communication device when the optical line free signal is detected. Generating means, an optical line use permission signal detecting means for detecting an optical line use permission signal transmitted from the other optical wireless communication device, and after transmitting a signal to the other optical wireless communication device,
When waiting for a certain period of time ignoring the first optical line idle signal transmitted from the other optical wireless communication device, and detecting an optical line use permission signal from the other optical wireless communication device within the certain time period And a transmission / reception control means for transmitting a new signal to the other optical wireless communication device as necessary.