JP2002135213A - Optical radio unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem of an optical radio unit that heat dissipating mechanism cannot be eliminated or simplified, and reduction in size, weight or power consumption is difficult. SOLUTION: A control section 11 is connected with a temperature detector 12, disposed in the vicinity of a light-emitting element 14. The control section 11 monitors temperature rise of the light-emitting element 14 through the temperature detector 12 and interrupts transmission/reception of data on the trunk 4 and the optical space side, when the detected temperature exceeds a prescribed threshold level.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical wireless device for transmitting an information signal by an optical wireless signal, and more particularly, to reduction of heat generation and power consumption of the optical wireless device.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 1, there is an optical wireless system for performing optical wireless information communication between an optical wireless master device 1 and a plurality of optical wireless slave devices 2a and 2b. This is because the optical wireless master device 1 is connected to a trunk line 4 such as a wired LAN stretched in the premises, and communicates with the optical wireless slave devices 2a and 2b within the communicable range of the optical wireless master device 1. Performs full-duplex or half-duplex two-way communication. And the optical wireless slave unit 2a,
2b is connected to processing devices 3a and 3b such as PCs, and communicates communication information with the optical wireless master device 1 to the processing devices 3a and 3b.
a and 3b.

Here, the optical wireless slave units 2a and 2b have a light emitting element and a light receiving element having a narrow directivity for transmitting and receiving an optical wireless signal to and from the optical wireless master unit 1. Further, the optical wireless master device 1 has a light emitting element and a light receiving element having a wide directivity,
A diffused light emitting master unit that transmits data simultaneously to all optical wireless slave units 2a and 2b within a certain service area by performing diffused light emission, and a plurality of optical wireless devices (sub- And a control unit for each sub-communication unit.

[0004] The diffuse light emitting type base unit can simultaneously communicate with all the optical wireless units in the service area, and there is no limit on the number of optical wireless units that can be transmitted. In addition, since there is no need to perform a search before starting transmission / reception, there is an advantage that it can be realized with a simple mechanism. On the other hand, since light is emitted over a wide range, there is a high possibility that the light emitted from oneself is reflected back to a surrounding object, and this returned reflected light becomes noise with respect to a signal received from the optical wireless client. . In addition, in order to emit light over a wide range, it is necessary to emit a great number of LEDs in all directions, and there is a disadvantage that heat generation and power consumption are increased. Furthermore, since a condensing lens cannot be used, in order to extend the communication distance,
There is a disadvantage that the number of LEDs can only be increased.

In addition, since the banana tuft-type master unit emits and receives light with a narrow directivity when transmitting and receiving to and from the optical wireless slave unit, there is almost no possibility of receiving the reflected light. There are advantages that the number can be reduced, and that the use of a condenser lens can extend the light receiving / emitting distance. However, since it is necessary to know the position of the optical wireless communication device before performing transmission and reception, it is necessary to perform a search operation, which requires a complicated search mechanism, and also depends on the number of LEDs to be used. There is a drawback that the number of communicable slave units is limited.

Generally, an LED (light emitting diode) is used as a light emitting element in the optical wireless master device and the optical wireless slave device. A constant DC current is passed through this LED and its D
A signal can be transmitted by increasing or decreasing the current with a constant amplitude around the C current and changing the light emission amount of the LED.

[0007]

Since the optical wireless master device 1 has many light emitting elements, it is common practice to stop light emission during non-data transmission in order to reduce power consumption. .

However, the optical wireless master unit 1 is
It is necessary to emit light not only when transmitting and receiving signals between the optical wireless communication devices 2a and 2b, but also when transmitting and receiving signals between the optical wireless communication devices 2a and 2b. When the period is long and the amount of communication data increases, light emission cannot be stopped.

Thank you very much. That is, in the case of having the light emission stop mechanism during non-communication, the average power consumption and the calorific value can be reduced, but the peak power consumption and the calorific value cannot be reduced. Therefore, a heat radiation mechanism equivalent to a system that emits light constantly is required.

SUMMARY OF THE INVENTION It is an object of the present invention to control a light emission time (communication amount) according to a heat generation amount to suppress heat generation, thereby simplifying a heat generation mechanism and reducing costs.

[0011]

As means for achieving the above object, the present invention aims to provide the following optical radio apparatus.

1. An optical wireless device that performs communication by an optical signal by performing diffused light emission to a plurality of slave units disposed in a predetermined service area, and a temperature detection unit that detects a temperature of a light-emitting unit that performs diffused light emission. Control means for controlling reception of received data, wherein when the temperature detected by the temperature detection means reaches a predetermined temperature, data reception is restricted by the control means.

2. An optical wireless device that performs communication by an optical signal by performing diffused light emission to a plurality of slave units disposed in a predetermined service area, and a temperature detection unit that detects a temperature of a light-emitting unit that performs diffused light emission. Control means for controlling transmission of transmission data, wherein when the temperature detected by the temperature detection means reaches a predetermined temperature, the control means restricts data transmission to the slave unit. Optical wireless device.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The optical wireless device according to the present invention restricts the amount of communication according to the temperature of the optical wireless device, thereby suppressing the heat generation of the light emitting element and omitting or simplifying the heat radiation mechanism. It can be manufactured at low cost and can reduce power consumption. Hereinafter, specific embodiments of the present invention will be described.

First, an optical wireless device to which the present invention is applied and a wireless communication system will be described with reference to FIG. As shown in FIG. 1, an optical wireless master unit 1 and a plurality of optical wireless slave units 2a, 2
b. An optical wireless system for performing optical wireless information communication between
An optical wireless master device 1 is connected to a trunk line 4 such as a wired LAN stretched in the premises, and all of the optical wireless master devices 2a and 2b within the communicable range of the optical wireless master device 1 are connected. It performs double or half duplex bidirectional communication. The optical wireless slave units 2a and 2b are connected to processing devices 3a and 3b such as PCs, and transmit and receive communication information with the optical wireless master device 1 to and from the processing devices 3a and 3b.

Here, each of the optical wireless slave units 2a and 2b has a light emitting element and a light receiving element having a narrow directivity for transmitting and receiving an optical wireless signal to and from the optical wireless master unit 1. Further, the optical wireless master device 1 has a light emitting element and a light receiving element having a wide directivity,
A diffused light emitting master unit that transmits data simultaneously to all optical wireless slave units 2a and 2b within a certain service area by performing diffused light emission, and a plurality of optical wireless devices (sub- As described in detail in the related art, there are two types: a banana tuft base unit having a communication unit) and a control mechanism for each sub communication unit.

For example, when data transmission is performed from the optical wireless slave device 2a in an optical wireless system performing half-duplex communication, first, the optical wireless slave device 2a transmits a transmission permission request signal including its own ID. If the optical wireless master device 1 determines that communication is possible based on the state of the communication channel when receiving the signal, the optical wireless master device 1 transmits a transmission permission signal including the ID of the optical wireless slave device 2a in the service area. (In the figure). The optical wireless client device 2a starts data transmission after receiving the transmission permission signal (in the figure). In addition, the other optical wireless slave 2b receives the transmission permission signal including the ID of the optical wireless slave 2a,
Recognizing that the communication channel is being used by the optical wireless communication device 2a, the data transmission request is to be kept down.

FIG. 2 is a block diagram showing a main part of the first embodiment of the optical wireless device of the present invention used in such an optical communication system. Optical wireless device 1A shown in FIG.
Is a diffuse light emitting type master unit, and a control unit 1 for restricting communication with respect to the trunk line 4 and the optical wireless slave unit (not shown).
One.

Further, a light emitting element 14 for transmitting a signal to the optical wireless handset, a light emission driving device 13 for driving the light emission of the light emitting element 14, a light receiving element for receiving a signal from the optical wireless handset It comprises an element 15 and a receiving device 16 for converting an optical signal received by the light receiving element 15 into an electric signal.

Further, a temperature detecting device 12 provided near the light emitting element 14 is connected to the control section 11, and the control section 11 monitors the temperature rise by the light emitting element 14 by the temperature detecting apparatus 12. And
When the detected temperature exceeds a predetermined threshold temperature, data transmission / reception on the trunk line 4 and the optical space side is stopped.
Alternatively, the threshold temperature is set with a plurality of values, and the data transmission / reception amount on the trunk line 4 and the optical space side is reduced at a fixed rate depending on the detected temperature. 6 and 7 are graphs with the detected temperature on the horizontal axis and the packet restriction ratio (%) on the vertical axis, and FIG. 6 shows the relationship between the trunk line 4 and the optical space when the temperature exceeds a predetermined threshold temperature. FIG. 7 is a graph showing a case in which the data transmission / reception is controlled to be stopped. When the temperature exceeds the threshold temperature, the data transmission / reception amount on the trunk line 4 and the optical space side is reduced at a fixed rate according to the rise in the detected temperature. It is a graph which shows the case where it controls. FIG. 8 shows a case where the threshold temperature is set at a plurality of values, and control is performed so as to reduce the data transmission / reception amount on the trunk line 4 and the optical space side stepwise at a fixed rate according to a change in the detected temperature. It is a graph.

As a specific method of controlling the data transmission / reception amount, for example, when communication is performed by Ethernet (registered trademark), when the detected temperature reaches the threshold temperature, the optical wireless master device 1A By transmitting a dummy packet and intentionally causing a packet collision, data transmitted from the trunk line 4 can be limited.
Also, a method of transmitting a dummy packet from the optical wireless master device 1A to the optical wireless slave device or a predetermined unique control signal is transmitted to the optical wireless slave device (optical space side). There is a method in which control is performed so that a dummy packet is transmitted from the optical wireless slave to the processing device side wired to the optical wireless slave. FIG. 4 is a flowchart illustrating an example of a method of controlling the amount of data transmission / reception in the optical wireless master device 1A when the Ethernet is used.

Referring to FIG. 1, first, an optical wireless master device 1A transmits a communication signal (packet signal) from an optical wireless slave device (optical space side).
Is detected (step 21). If there is no packet signal from the optical space side (step 21 → N), reception of a communication signal (packet signal) from the trunk line 4 is detected (step 22). If there is no packet signal from the trunk side 4 (step 22 → N), since no communication signal is coming from any of them, the process returns to step 21 as it is.

If there is a packet signal from the trunk line 4 (step 22 → Y), the detected temperature value detected by the temperature detecting device 12 is compared with the threshold temperature value (step 2).
3) If the detected temperature value exceeds the threshold temperature value (step 23 → the threshold temperature value or more), a dummy packet for collision is transmitted to the trunk line 4 to reduce the amount of communication data to be transmitted and received, thereby enabling communication. Notifying the main line 4 that there is no data, the process is terminated (step 24). If the detected temperature value is equal to or lower than the threshold temperature value (step 23 → lower than the threshold temperature value), the packet signal from the trunk line 4 is converted into an optical signal and transmitted to the optical wireless client (step 23). 25).

In step 21, even if there is a packet signal from the optical space side (step 21 → Y), the reception of a communication signal (packet signal) from the trunk line 4 is detected in the next step (step 26). . If there is a packet signal from the trunk side 4 (step 26).
→ Y) Since communication signals are coming from both,
A collision packet is transmitted to the trunk line side 4 to inform the trunk line side 4 that communication was not possible (step 27), and the collision packet converted into an optical signal is transmitted to the optical wireless slave unit.
By colliding with a communication signal from the optical wireless slave, the optical wireless slave is notified that communication could not be performed (step 28).

In step 26, when there is no packet signal from the trunk line 4 (step 26 → N), the detected temperature value detected by the temperature detecting device 12 is compared with the threshold temperature value (step 29). ), If the detected temperature value exceeds the threshold temperature value (step 29 → above the threshold temperature value),
In order to reduce the amount of transmission and reception of communication data, a collision packet converted into an optical signal is transmitted to the optical wireless subunit, and cannot be communicated with the optical radio subunit by colliding with a communication signal from the optical wireless subunit. (Step 30). In this case, since the optical wireless slave does not retransmit for a predetermined time after the collision is detected, light emission of the light emitting element 14 of the optical wireless master unit 1A can be suppressed as a result.

If the detected temperature value is equal to or lower than the threshold temperature value (step 29 → lower than the threshold temperature value), the trunk line 4 or the optical space is determined based on the transmission destination ID of the packet signal from the optical wireless slave unit. (When the destination ID is another optical wireless handset)
The received packet signal is transmitted to the device (step 31).

In Steps 28 and 30, a collision dummy packet is transmitted to the optical wireless slave to notify the optical wireless slave that communication could not be performed. May be configured to transmit (ignore) nothing even if a signal is received from the optical wireless communication device, thereby notifying the optical wireless communication device that communication could not be performed. In this case, the optical wireless slave device does not receive a reply signal from the optical wireless master device 1A within a predetermined time, so that the transmitted signal was not received by the optical wireless master device 1A (communication was not possible). You can know.

As shown in FIGS. 7 and 8, when the packet limiting ratio is controlled based on the detected temperature, in steps 23 and 29, the temperature detector 12 is used.
A control signal corresponding to the detected temperature value detected in the step (a) is transmitted to the control unit 11, and steps 24 and 30
, The transmission is performed while controlling the transmission frequency ratio of the collision dummy packet. For example, a collision dummy packet is transmitted for 1 to 10 out of 10 packet reception times. The transmission rate is controlled so as to increase in proportion to the detected temperature. If the collision dummy packet is not transmitted in step 30, control is performed such that the communication signal from the optical wireless communication device is ignored at a predetermined number of times that increases in proportion to the detected temperature.

As described above, in the above embodiment, when the detected temperature is equal to or higher than the predetermined temperature, the amount of light emitted from the light emitting element 14 is controlled by controlling the amount of communication. The radiation fins and the cooling fan) can be eliminated or simplified, and the optical wireless master device can be reduced in size and weight. Further, power consumption can be reduced. Further, when a fan is used as the heat radiation mechanism, it can also function as a safety mechanism when the fan is broken. in this case,
A trade-off between temperature rise and communication performance can be realized.

FIG. 3 is a block diagram showing a main part of a second embodiment of the optical radio apparatus according to the present invention. The optical wireless device 1B shown in the figure is a diffuse light emitting type master unit, and has a switching function (a function of having a memory, detecting a transmission destination, and distributing data only to necessary ports) and a temperature detection device. I have. Then, the memory 18 for temporarily storing the signal received from the trunk line 4 with respect to the trunk line 4 and the optical wireless slave device (not shown), and the signal stored in the memory 18 to the optical wireless slave device side. And a control unit 19 for controlling communication according to the detected temperature.

Further, a light emitting element 14 for transmitting a signal to the optical wireless handset, a light emission driving device 13 for driving light emission of the light emitting element 14, and a light receiving element for receiving a signal from the optical wireless handset It comprises an element 15 and a receiving device 16 for converting an optical signal received by the light receiving element 15 into an electric signal.

Further, a temperature detecting device 12 provided near the light emitting element 14 is connected to the control section 19, and the control section 19 monitors the temperature rise by the light emitting element 14 by the temperature detecting apparatus 12. And
When the detected temperature exceeds a predetermined threshold temperature, the transmission amount of data received from the main line 4 is reduced (delayed) at a fixed rate according to the detected temperature. 6 to 8 are graphs with the detected temperature on the horizontal axis and the packet restriction ratio (%) on the vertical axis. FIG. 6 shows the data received from the trunk line 4 when the temperature exceeds a predetermined threshold temperature. FIG. 7 is a graph showing a case in which data transmission to the optical space side is controlled to be stopped. FIG. 7 shows a graph of data received from the trunk line 4 at a constant rate due to a change in detected temperature when a predetermined threshold temperature is exceeded. 9 is a graph showing a case where control is performed to reduce a transmission amount (light emission amount). Further, FIG. 8 is a graph showing a case where the threshold temperature is set at a plurality of values, and control is performed so as to reduce the amount of data transmission to the optical space side at a constant rate according to a change in the detected temperature. is there.

The switching chip 17 has a general switching function for transmitting a packet received from the trunk line 4, and has a function of performing switching control even when data overflows from the capacity of the memory 18. I have.

In the present embodiment, with the above configuration,
When the data received from the trunk line 4 is temporarily stored in the memory 18 and the received signal is transmitted to the optical wireless communication device,
The light emission of the light emitting element 14 is controlled according to the temperature detected by the temperature detection device 12.

Here, the operation of the control unit 19 between the switching chip 17 and the light emitting element 14 when using Ethernet will be described with reference to the flowchart shown in FIG. First, when a packet signal is received from the trunk line 4, the packet signal is stored in the memory 18 via the switching chip 17. Then, the packet data stored in the memory 18 is supplied to the light emission driving device 13 via the switching chip 17 and the control unit 19 and photoelectrically converted, and the light emitting element 14 transmits the packet data to the optical wireless device (optical space side). An optical signal is output. At this time, the control unit 19 performs transmission control according to the temperature detected by the temperature detection device 12.

More specifically, when transmitting a packet signal to the optical space side (step 41), the detected temperature detected by the temperature detecting device 12 is compared with a threshold temperature (step 42). If there is (step 42 → below threshold temperature), the packet data is transmitted as it is (step 43). If the detected temperature exceeds the threshold temperature (step 42 → threshold temperature or more), for example, a collision dummy packet is transmitted to the switching chip 17 so that transmission to the optical space side is not performed. (Step 44). The transmission control to the optical space side may be controlled such that the probability of transmission to the optical space side decreases as the detected temperature increases, as shown in FIGS.

The object of the present invention can be achieved only by implementing one of the above-described first and second embodiments. The present invention may be embodied as an optical wireless device having both of the configurations of the second embodiment.

[0038]

According to the optical wireless device of the present invention, the light emission is controlled by the temperature of the light emitting element, so that the heat radiating mechanism (radiating fins and cooling fan) can be omitted or simplified. It is possible to reduce the size and weight. Further, power consumption can be reduced.

When a cooling fan is used as a heat radiating mechanism, the cooling fan can be used as a safety mechanism when the cooling fan is broken or when a rise in temperature cannot be avoided with the cooling fan alone. Thereby, there is an effect that a trade-off between the temperature rise and the communication performance can be realized.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram illustrating a configuration example of an optical wireless system.

FIG. 2 is a configuration diagram illustrating a first embodiment of the optical wireless device of the present invention.

FIG. 3 is a configuration diagram showing a second embodiment of the optical wireless device of the present invention.

FIG. 4 is a flowchart showing the operation of the first embodiment of the optical wireless device of the present invention.

FIG. 5 is a flowchart illustrating an operation of the optical wireless device according to the second embodiment of the present invention.

FIG. 6 is a graph showing an example of transmission / reception control contents in the present invention.

FIG. 7 is a graph showing another example of transmission / reception control contents in the present invention.

FIG. 8 is a graph showing still another example of transmission / reception control contents in the present invention.

[Explanation of symbols]

 1, 1A, 1B Optical wireless master device (optical wireless device) 2a, 2b Optical wireless slave device 3a, 3b Processing device 4 Main line 11, 19 Control section (control means) 12 Temperature detecting device (temperature detecting means) 13 Light emission driving device 14 light emitting element 15 light receiving element 16 receiver 17 switching chip 18 memory

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04L 12/28

Claims (2)

[Claims] An optical wireless device that performs communication by an optical signal by performing diffused light emission to a plurality of slave units disposed in a predetermined service area, wherein the temperature of a light emitting unit that performs diffused light emission is detected. Temperature detecting means, and control means for controlling reception of received data, wherein when the temperature detected by the temperature detecting means reaches a predetermined temperature, data reception is limited by the control means. Optical wireless device. 2. An optical wireless device for performing communication by an optical signal by performing diffused light emission to a plurality of slave units disposed in a predetermined service area, wherein a temperature of a light emitting means for performing diffused light emission is detected. Temperature detecting means, and control means for controlling transmission of transmission data, wherein when the temperature detected by the temperature detecting means reaches a predetermined temperature, the control means restricts data transmission to the slave unit. An optical wireless device, comprising: