JP2003169025A - Optical axis adjusting method of optical radio communication terminal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To shorten the time spent for optical axis alignment by immediately performing optical axis alignment matching the link state of optical radio of an optical radio communication terminal without any unnecessary stage and to perform optical communication normally by accurately align both an up optical axis and a down optical axis. <P>SOLUTION: The optical radio communication terminal 10 sends a test packet to an optical radio collecting and distributing device 20. The optical radio collecting and distributing device sends an answer to the test packet and the optical radio communication terminal receives the answer. The optical radio communication terminal decides the optimum optical axis adjusting method among a plurality of optical axis adjusting methods which are different in matching accuracy between transmission-side and reception-side optical axes according to the answer result so that transmission and reception can be carried out, and then informs an optical axis alignment control means 18 of the decision result. The optical axis alignment control means drives a servo means 19 according to the selected optical axis adjusting method to adjust the position of an optical receiving means 15. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical axis adjusting method in an optical wireless communication terminal for transmitting and receiving data by an optical wireless signal, and more particularly to an optical wireless method capable of executing a plurality of optical axis adjusting methods having different accuracies. The present invention relates to an optical axis adjustment method in a communication terminal.

[0002]

2. Description of the Related Art In the conventional optical axis adjusting method for an optical wireless communication terminal, for example, as disclosed in Japanese Patent Laid-Open No. 6-224858, a ceiling is provided by an optical wireless communication terminal connected to a station such as a PC. The optical wireless communication terminal and the optical wireless collection and distribution device are accurately aligned by performing an automatic search for the optical wireless collection and distribution device attached to the optical disk using the servo means.

At this time, the optical wireless communication terminal searches for an optical wireless collecting and delivering apparatus within a horizontal direction of a horizontal angle of 0 to 150 degrees and a vertical inclination of a vertical direction of 75 degrees, and has an accuracy of 5 degrees. The optical axes are aligned below. As described above, in order to search the wide space and align the position with the narrow optical axis, in the conventional technique, if the link cannot be confirmed, as shown in the flowchart of FIG.
In 1000, a step of specifying a rough direction in which the optical wireless device is present (hereinafter referred to as a step of coarse adjustment 1), and in step S2000, a step of searching for the strongest direction of communication light from the specified rough direction (hereinafter , In the coarse adjustment 2), and in step S3000, the optical axis alignment is performed in a three-step process of pushing the direction into a communicable state (hereinafter referred to as the fine adjustment step).

The following is a description of the steps of coarse adjustment 1, coarse adjustment 2, and fine adjustment performed in the conventional adjustment of the optical axis. FIG. 13 is a schematic diagram showing the light receiving intensity region of the light receiving means of the optical wireless communication terminal. The light receiving intensity of the light receiving means (reception efficiency of light received from the light source) changes according to the position of the optical axis of the light from the light source on the light receiving means. The center position of the X-axis and the Y-axis of FIG. 13A is the position where the received light intensity is maximum, and in FIG. 13B, as the optical axis shifts from this center position, the optical wireless communication terminal The manner in which the received light intensity decreases is illustrated.

First, the details of the step of coarse adjustment 1 in step S1000 shown in FIG. 12 will be described. FIG. 7 is a flow chart for explaining the stage of coarse adjustment 1 in the optical axis adjusting method common to the prior art and the present invention. In the step of coarse adjustment 1, a threshold value of a relatively low received light intensity (hereinafter, referred to as a first threshold value) is set, pilot light or link light is searched for in a roughly set predetermined range, and the first threshold value is set. A light receiving intensity region α having a light receiving intensity exceeding is searched.

First, in step S1001, the range for searching the optical axis is determined, and the horizontal direction and inclination of the optical receiving means of the optical wireless communication terminal are set as the initial position for searching the optical axis.
Then, in step S1002, the received light intensity is confirmed, and in step S1003, the received light intensity is the first
Is greater than the threshold value (light reception intensity> first threshold value). When the received light intensity is less than or equal to the first threshold value, the direction of the light receiving means of the optical wireless communication terminal is changed to a predetermined horizontal direction (horizontal direction or tilt direction).

That is, for example, regarding a predetermined range,
When scanning in the horizontal direction while fixing the inclination, first,
In step S1004, it is determined whether the horizontal scanning is completed. If the scanning in the horizontal direction has not been completed, the direction of the light receiving means is changed to the horizontal direction by a predetermined distance in step S1005. On the other hand, if the scanning in the horizontal direction has ended, it is determined in step S1006 whether or not the scanning in the tilt direction has ended. If the scanning in the tilt direction has not ended, step S1 is performed.
In 007, the direction of the light receiving means is changed to the tilt direction by a predetermined angle, and the received light intensity in step S1002 is checked again.

In this way, while changing the direction of the light receiving means of the optical wireless communication terminal in a certain coarse step, the predetermined range is swiftly scanned, and the received light intensity of the light receiving means is observed, When the received light intensity larger than the threshold value is detected, the process proceeds to the step of coarse adjustment 2 (step S2000). At this time, the light receiving means of the optical wireless communication terminal has detected the received light intensity region α shown in FIG. It should be noted that even if the entire predetermined range is scanned (that is, the scanning in the tilt direction is determined to be completed in step S1006), if the received light intensity equal to or higher than the first threshold value cannot be detected, the predetermined range is set. It is determined that the desired light (pilot light / link light) does not exist.

Next, details of the step of coarse adjustment 2 in step S2000 shown in FIG. 12 will be described. FIG. 8 is a flow chart for explaining the steps of coarse adjustment 2 in the optical axis adjusting method common to the prior art and the present invention. In the coarse adjustment 2, the direction of the optical receiving means of the optical wireless communication terminal is changed to the coarse adjustment 1.
The setting is made more finely than in the step, and the direction is adjusted so that the received light intensity of the pilot light or the link light becomes larger. In this case, a threshold value of the received light intensity larger than the first threshold value (hereinafter referred to as the second threshold value) is set, and the region β having the received light intensity exceeding the second threshold value is searched.

First, in step S2001, the received light intensity is confirmed, and in step S2002, it is determined whether the received light intensity is larger than a second threshold (received light intensity> second threshold). If the received light intensity is less than or equal to the second threshold value, it is determined in step S2003 whether the received light intensity is greater than the first threshold value (received light intensity> first threshold value), and the received light intensity is less than or equal to the first threshold value. If, then step S
In 2005, the direction of the light receiving means is changed to the tilt direction by a predetermined angle, and the received light intensity in step S2001 is checked again. On the other hand, when the received light intensity is larger than the first threshold value, in step S2006, the direction of the light receiving means is changed to the horizontal direction by a predetermined distance,
The received light intensity in step S2001 is checked again.

In this way, while changing the direction of the light receiving means of the optical wireless communication terminal in a certain step, the light receiving intensity region larger than the first threshold value is scanned to observe the light receiving intensity of the light receiving means. , If the received light intensity larger than the second threshold value is detected, the process proceeds to the fine adjustment stage (step S3000). At this time, the optical receiving means of the optical wireless communication terminal is shown in FIG.
This means that the received light intensity region β shown in is detected. It should be noted that even if all the range in which the received light intensity is equal to or higher than the first threshold value is scanned (that is, the scanning in the tilt direction is determined to be finished in step S2004), the received light intensity equal to or higher than the second threshold value cannot be detected. In the predetermined range, the light detection fails.

FIG. 14 is a schematic view showing an example of the trajectory of the light source at the steps of coarse adjustment 1 and coarse adjustment 2 of the conventional optical axis adjusting method. As shown in FIG. 14, first, in the coarse adjustment 1 stage, the received light intensity region α in which the received light intensity is larger than the first threshold value is detected, and then in the coarse adjustment 2 stage, the received light intensity is larger than the second threshold value. The received light intensity region β can be detected.

Next, details of the fine adjustment stage of step S3000 shown in FIG. 12 will be described. In this fine adjustment stage, the link light that finally enables optical communication is adjusted so as to overlap with the optical receiving means. FIG. 15 shows a PD (Photo Detect) divided into four cells used for the optical receiving means.
or: photodetector), and FIG. 16 is a schematic diagram showing an example of the locus of the received light in the fine adjustment stage. At the fine adjustment stage, as disclosed in Japanese Patent Laid-Open No. 6-224858, the PD is equally divided into four cells.
40 is used for the optical receiving means of the optical wireless communication terminal, and the orientation of the optical receiving means is adjusted so that each of the divided cells has an equal reception intensity. Note that in actual communication, only a specific cell is used, so the orientation of the optical receiving means is finally adjusted so that the reception intensity can be secured in this specific cell.

FIG. 9 is a flow chart for explaining the fine adjustment steps in the optical axis adjusting method common to the prior art and the present invention. First, in step S3001, the received light intensities of the four cells are confirmed, and in step S3002, it is determined whether the received light intensities of the cells A and D shown in FIG. 15 are equal (A = D). to decide. When the received light intensity of the cell A is not equal to the received light intensity of the cell D, in step S3003, the direction of the light receiving means is changed to the horizontal direction by a predetermined distance, and the received light intensity in step S3001 is changed again. Confirm.

If the received light intensity of the cell A and the received light intensity of the cell D are equal, in step S3004
It is determined whether the received light intensity of the cell B shown in FIG. 15 and the received light intensity of the cell C are equal (B = C). When the received light intensity of the cell B is not equal to the received light intensity of the cell C,
In step S3005, the direction of the light receiving means is changed to the tilt direction by a predetermined angle, and step S30 is performed again.
The received light intensity at 01 is confirmed.

When it is determined in step S3002 that the received light intensity of the cell A and the received light intensity of the cell D are equal, the center point (4 points) of the light receiving means is set on Y = X in FIGS. The point where the cells touch) will exist. If it is determined in step S3004 that the received light intensity of the B cell and the received light intensity of the C cell are equal,
The center point of the optical receiving means (the point where four cells are in contact) exists on Y = −X in FIGS. 13 and 14.
That is, when the received light intensity of the cell A is equal to the received light intensity of the cell D, and the received light intensity of the cell B is equal to the received light intensity of the cell C, the optical reception of the optical wireless communication terminal is performed. In this state, the intensity of light received at the center of the means is maximum (the position of the optical axis). Then, in step S3006, the optical axis is aligned with a specific cell that is actually communicating, and the orientation of the optical receiving means is finally adjusted so that the reception intensity can be secured in this specific cell.

[0017]

However, in the conventional optical axis adjusting method, in the step of the coarse adjustment 1, an extremely wide range is searched compared with the directional characteristics of the optical receiving means, and therefore the existence of the optical wireless collection and delivery apparatus is required. The problem is that it takes a very long time to confirm. Furthermore, there are cases where the optical communication link cannot be established even if the optical axis alignment procedure is performed once, and in this case, there is a problem that the optical axis alignment procedure needs to be repeated from the beginning.

Further, in the conventional optical axis adjusting method, it is possible to match the optical axis from the optical wireless concentrator / distributor to the optical wireless communication terminal (hereinafter referred to as the downstream optical axis). The optical axis from the communication terminal to the optical wireless collection and delivery device (hereinafter, referred to as an upstream optical axis) does not always match. For this reason, a situation may occur in which the downstream optical axis is aligned but the upstream optical axis is not aligned, and although the optical axes are properly aligned and linked, communication may not be possible. There is.

In order to solve the above-mentioned problems, according to the present invention, the optical axis alignment suitable for the optical wireless link state of the optical wireless communication terminal is immediately performed without performing unnecessary steps, and the time spent for the optical axis alignment. It is an object of the present invention to shorten the optical path length and accurately align both the upstream optical axis and the downstream optical axis so that optical communication can be performed normally.

[0020]

In order to achieve the above object, the present invention provides an optical wireless communication terminal which transmits a test packet to an optical wireless collection and delivery apparatus, and a response from the optical wireless collection and delivery apparatus to the test packet. Depending on the result, select any one of a plurality of optical axis adjustment methods with different matching accuracy between the transmission side and the reception side optical axis so that transmission and reception can be performed,
I'm trying to run.

That is, according to the present invention, it is possible to transmit and receive the data by the optical wireless signal to and from the optical wireless concentrator for collecting and delivering the data by the optical wireless signal, and to perform the transmission and reception. In an optical axis adjusting method in an optical wireless communication terminal capable of executing a plurality of optical axis adjusting methods having different matching precisions between transmitting side and receiving side optical axes, a test packet is transmitted to the optical wireless collecting and delivering apparatus. And a step of selecting and executing any one of the plurality of optical axis adjusting methods according to a result of a response from the optical wireless concentrator to the test packet. An optical axis adjusting method in a wireless communication terminal is provided.

In order to achieve the above object, according to the present invention, an optical wireless communication terminal transmits a test packet to an optical wireless collecting and delivering apparatus a plurality of times, and the optical wireless collecting and delivering apparatus responds to each of the plurality of test packets. One of a plurality of optical axis adjusting methods with different matching accuracy between the transmitting side and the receiving side optical axes so that transmission / reception can be executed according to the accumulated result I'm trying to select and run.

That is, according to the present invention, it is possible to transmit and receive the data by the optical wireless signal to and from the optical wireless concentrator that collects and delivers the data by the optical wireless signal, and to perform the transmission and reception. In an optical axis adjusting method in an optical wireless communication terminal capable of executing a plurality of optical axis adjusting methods with different matching accuracy between transmitting side and receiving side optical axes, a test packet is transmitted to the optical wireless collecting and delivering apparatus a plurality of times. A step of transmitting, a step of accumulating results of a plurality of times of responses from the optical wireless concentrator to each of the plurality of test packets, and a plurality of optical axis adjustments according to cumulative results of the accumulating step. A method for selecting and executing any one of the methods, and a method for adjusting an optical axis in an optical wireless communication terminal.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of an optical axis adjusting method in an optical wireless communication terminal of the present invention will be described below with reference to the drawings. First, the configuration of the optical wireless communication terminal 10 used in the present invention will be described. FIG. 1 is a block diagram showing a configuration example of an optical wireless communication terminal used in the present invention. The optical wireless communication terminal 10 shown in FIG. 1 includes a receiving unit 11, a communication data processing unit 12, an optical communication procedure processing unit 13, an optical transmitting unit 14, an optical receiving unit 15, and a transmitting unit 1.
6, pilot light extraction means 17, optical axis alignment control means 1
8 and servo means 19.

The receiving means 11 is an interface function for receiving data transmitted from an external device (not shown) such as a personal computer or (PC) workstation (WS) connected to the optical wireless communication terminal 10. Is a means of having. The communication data processing means 12 is
This is a means for performing a procedure process for transmitting the data received by the receiving means 11 to the optical wireless collection and delivery apparatus 20.

The optical communication procedure processing means 13 is means for performing procedure processing for performing an optical wireless communication procedure with the optical wireless collection and distribution device 20. The optical transmission unit 14 receives the communication signal generated by the optical communication procedure processing unit 13 for performing the optical communication procedure and the communication data to be transmitted to the optical wireless concentrator 20 processed by the communication data processing unit 12. , A means for converting the light signal into an optical signal, causing the light emitting element to emit light, and transmitting the optical signal to the optical wireless concentrator 20.

The optical receiving means 15 receives the optical signal transmitted from the optical wireless concentrator / distributor 20 and outputs it to the PD (photodetector) 4
It is a means for receiving light by a light receiving element such as 0, photoelectrically converting it, and outputting it. The transmitting unit 16 outputs the communication data output from the optical receiving unit 15 and processed by the communication data processing unit 12 from the optical wireless concentrator 20 to an external device (not shown) such as a PC or WS connected to itself. Is a means for sending to.

The pilot light extraction means 17 is means for extracting the pilot light of the optical wireless concentrator 20 from the optical reception signal output from the optical reception means 15. The optical axis alignment control unit 18 is a unit that controls the optical axis alignment with the optical wireless concentrator 20 by using the pilot light extracted by the pilot light extraction unit 17. In addition, the optical axis alignment control means 18 transmits a signal requesting which optical axis adjustment method is selected from among a plurality of optical axis adjustment methods having different accuracies to the communication control block, and the communication control block determines the result. Accordingly, the optical axis adjusting method is selected and the servo means 19 is driven. The servo means 19 is means for converting the control signals for the servo mechanism such as pan and tilt output from the optical axis alignment control means 18 into motive power, and changing the orientations of the light transmitting means 14 and the light receiving means 15.

Next, the configuration of the optical wireless collection and delivery device 20 used in the present invention will be described. FIG. 2 is a block diagram showing an example of the configuration of the optical wireless collecting and distributing apparatus used in the present invention.
The optical wireless collection and distribution apparatus 20 shown in FIG. 2 includes an optical receiving means 21, a communication data processing means 22, an optical communication procedure processing means 23, a transmitting means 24, a receiving means 25, an optical transmitting means 26, a pilot light generating means 27, a pilot light. It has a transmitting means 28.

The optical receiving means 21 converts a light receiving element such as a PD (photodetector) 40 for receiving an optical wireless signal transmitted from the optical wireless communication terminal 10 and an optical signal received by the light receiving element into an electric signal. It is a means composed of a photoelectric conversion unit. The communication data processing means 22 is means for extracting communication data from the optical wireless communication terminal 10 and transferring it in an appropriate direction such as the optical space direction or the main line direction.

The optical communication procedure processing means 23 is means for extracting a communication signal from the optical wireless communication terminal 10 from the optical signal received by the optical receiving means 21 and performing control for optical wireless communication. The transmission unit 24 is a unit that outputs a signal (communication data or collision notification signal) to be transmitted to the trunk line or the like.
The receiving means 25 is means for receiving communication data by connecting to a trunk line or the like.

The optical transmission means 26 converts a communication signal (optical communication procedure signal or communication data) to be transmitted to the optical space into an optical signal and transmits it to the optical wireless communication terminal 10 by a light emitting means such as a light emitting diode. Is a means to do. The pilot light generating means 27 and the pilot light transmitting means 28 generate pilot light and radiate it into space in order for the optical wireless communication terminal 10 which is going to establish a connection with the optical wireless concentrator / distributor 20 by optical communication to perform optical axis alignment. Is a means to do.

A network forming a star topology is formed between the plurality of optical wireless communication terminals 10 having the above-mentioned configuration and the optical wireless communication device 20, and each optical wireless communication terminal is formed via the optical wireless communication device 20. It is possible to perform communication between 10 and between the trunk line and the optical wireless communication terminal 10. Hereinafter, this optical wireless communication terminal 10
The operation of the optical axis adjusting method in the optical wireless communication terminal performed in the preparation stage of the optical communication between the optical wireless communication device 20 and the optical wireless communication device 20 will be described.

<First Embodiment> First, a first embodiment of the optical axis adjusting method in the optical wireless communication terminal 10 of the present invention will be described. 3 and 4 are flowcharts for explaining the first embodiment of the optical axis adjusting method in the optical wireless communication terminal of the present invention. Note that FIG. 3 is a flowchart common to the second embodiment described later.

In the first embodiment, first, step S
At 101, the optical wireless communication terminal 10 confirms the link light of the optical communication with the optical wireless collection and distribution device 20, for example, at startup. The optical wireless communication terminal 10 includes an optical wireless collection and delivery device 20.
The optical link signal is used to maintain the optical synchronization with the optical link signal, and the optical link signal is emitted during idle time when there is no optical communication data. When the optical wireless communication terminal 10 cannot confirm the received signal such as the optical link signal or the optical communication data for a certain period of time or more, it is determined that the optical axis for performing communication with the optical wireless collecting and delivering apparatus 20 is deviated, Align the optical axis.

In aligning the optical axes when the optical axes are deviated,
The optical axis adjusting method is selected according to the received light intensity (signal intensity) of the received signal received by the light receiving means 15. In step S103, the received light intensity is confirmed, and in step S103
At 105, it is determined whether the received light intensity is larger than the second threshold (received light intensity> second threshold). If the received light intensity is larger than the second threshold value, in step S107, the process proceeds to the stage of fine adjustment for fine optical axis alignment (flowchart shown in FIG. 9). On the other hand, when the received light intensity is less than or equal to the second threshold value, in step S109, whether the received light intensity is greater than the first threshold value (received light intensity> first threshold value).
To judge.

If the received light intensity is larger than the first threshold value, the received light intensity is set to the second threshold value in step S111.
The step of coarse adjustment 2 (flowchart shown in FIG. 8) for searching for a direction that becomes larger than the threshold value is performed, and when the received light intensity is less than or equal to the first threshold value, the received light intensity becomes greater than the first threshold value in step S113 The step of coarse adjustment 1 (flowchart shown in FIG. 7) for searching the direction is performed. Note that step S1
07 fine adjustment stage, step S111 coarse adjustment 2 stage,
After the step of coarse adjustment 1 in step S113 ends,
By returning to the confirmation of the link light of the optical communication in step S101, it is possible to determine again whether the link light of the optical communication can be confirmed and select the optical axis adjusting method.

On the other hand, when the link light can be confirmed in step S101 (that is, when the optical link signal and the optical communication data can be received), it is confirmed whether the optical communication is established. In step S121, the optical wireless communication terminal 10 generates the test packet 30, and in step S123,
If it is confirmed whether the optical transmission line is in the line idle state and the line is in the line idle state (that is, the state in which the test packet 30 can be transmitted), the test packet 30 is sent to the optical wireless concentrator 20 in step S125. To send.

FIG. 10 is a schematic diagram showing an example of the structure of a test packet and a communication frame. As shown in FIG. 10, the test packet 30 is used only for confirming the link of optical communication, and has a very small data capacity as compared with the communication frame 50. In addition, a value unique to each test packet 30 is set in the ID portion of the test packet 30 shown in FIG. In this way, a unique value is set for each test packet 30 so that each test packet 30 can be identified.

The test packet 30 generated in step S121 is a packet that is effective only in the optical space, and the optical wireless communication device 10 and all the optical wireless communication terminals 10 connected to the network receive the test packet 30. In this case, the format is such that this received signal can be recognized as the test packet 30. The test packet 30 is used only for confirming the link of the optical communication, and is processed by each optical communication procedure processing unit 13 so as not to be sent to the trunk line or the PC.

The optical wireless collection and delivery device 20 is an optical wireless communication terminal 1
When the test packet 30 from 0 is received and detected, this is taken in and the optical transmission line side (optical wireless communication terminal 10 side)
Optically transmit a response signal to. When the optical wireless communication terminal 10 receives the response signal from the optical wireless distribution device 20 in step S127, the optical wireless communication terminal 10 determines in step S129 whether the response signal is the response signal related to the test packet 30 transmitted in step S125. To do. If the response signal is the response signal to the test packet 30 transmitted in step S125, in step S131,
It is checked whether or not the contents match with the contents of the test packet 30 transmitted in step S125, and step S131
If the collation results in 1 above coincide with each other, it is determined in step S133 that the optical communication link is established, and the optical axis alignment is terminated.

On the other hand, if there is no response from the optical wireless concentrator / distributor 20 in step S127, the test packet 30 whose response signal is transmitted in step S125 is transmitted in step S129.
If it is not a response signal to (for example, the test packet 30 of another optical wireless communication terminal 10), step S
If the collation result of the test packet 30 does not match at 131, it is considered that the optical axis from the own terminal to the optical wireless distribution device 20 is slightly deviated, and therefore a fine adjustment step is performed. After the step of fine adjustment in step S135 ends, the process returns to the step S101 of checking the link light of the optical communication.

In this way, the state of the link light of the optical communication between the optical wireless communication terminal 10 and the optical wireless concentrator / distributor 20 is determined, and the test packet 30 is used to determine whether or not the link is established. By making a judgment, the most suitable optical axis adjustment method is selected according to the judgment result.
Appropriate optical axis alignment can be performed immediately without performing unnecessary steps, and the time spent for optical axis alignment can be shortened.

Further, by roughly determining the state of the link light of the optical communication between the optical wireless communication terminal 10 and the optical wireless collecting and distributing apparatus 20, for example, the step of coarse adjustment 1 for roughly adjusting the optical axis is completed. If the optical axis is correctly aligned and communication is possible, it is possible to make a determination again at that point,
It is possible to communicate immediately without performing the steps of coarse adjustment 2 and fine adjustment, and it is possible to perform appropriate optical axis alignment immediately without performing unnecessary steps, which is required for optical axis alignment. It is possible to shorten the time required for this. Further, since the optical axis alignment is performed using the result of the response of the optical wireless collection and distribution device 20, it is possible to accurately align both the upstream optical axis and the downstream optical axis so that optical communication can be performed normally. .

<Second Embodiment> Next, a second embodiment of the optical axis adjusting method in the optical wireless communication terminal 10 of the present invention will be described. FIGS. 3, 5, and 6 are flowcharts for explaining the second embodiment of the optical axis adjusting method in the optical wireless communication terminal of the present invention. Note that FIG.
3 is a flowchart common to the first embodiment described above.

In the second embodiment, similarly to the first embodiment, when the link light of the optical communication cannot be confirmed, it is determined whether the received light intensity is larger than the threshold values of the first and second threshold values. If the received light intensity is larger than the second threshold value, the fine adjustment step is performed. If the received light intensity is less than or equal to the second threshold value and larger than the first threshold value, the coarse adjustment 2 step is performed. Is less than or equal to the first threshold, the steps of coarse adjustment 1 are performed (steps S101 to S113 in FIG. 3).

When the link light of the optical communication can be confirmed, the optical wireless communication terminal 10 is used as in the first embodiment.
Transmits the test packet 30 to the optical wireless collection and distribution device 20 (steps S221 to S225 in FIG. 5). Then, when the optical wireless communication terminal 10 receives the response signal from the optical wireless collecting and delivering apparatus 20 in step S227,
In step S229, this response signal
It is determined whether or not it is the response signal related to the test packet 30 transmitted in 225. Then, this response signal is
In the case of the response signal to the test packet 30 transmitted in 225, it is verified in step S231 whether or not it matches the content of the test packet 30 transmitted in step S225, and the verification result in step S231 is matched. In this case, in step S233, the number of matches indicating that the matching results match is incremented by one.

On the other hand, if there is no response from the optical wireless collection and distribution device 20 in step S227, the number of non-detections indicating no response is incremented by 1 in step S235. If the response signal in step S229 is not the response signal to the test packet 30 transmitted in step S125 (for example, another optical wireless communication terminal 1
0 test packet 30), step S23
When the collation result of the test packet 30 does not match at 1, the number of mismatches indicating that the received test packet 30 is not the proper test packet 30 is incremented by 1 in step S237.

After any one of the number of times of coincidence, the number of times of non-detection and the number of times of non-coincidence is counted up by 1 in any of the processes of steps S233 to S237, the number of times of transmission is counted up by 1 in step S239. In step S241, the processing from step S101 is repeated until the number of times of transmission reaches a predetermined number (for example, 10 times), and the number of times of transmission reaches a predetermined number (10 times).
If it becomes, the state of the optical communication link is determined by referring to the number of coincidences in the subsequent processing.

First, in step S243, it is determined whether the number of coincidences matches the number of transmissions (10 times). If the number of coincidences coincides with the number of transmissions, it is determined in step S245 that the optical communication link is established, and optical axis alignment is unnecessary. If the number of matches does not match the number of times of transmission (10 times), step S2
47, the number of matches is more than half of the number of transmissions (5-9
If the number of coincidences is not more than half the number of transmissions (5 to 9 times), further step S24.
In 9, the number of matches is counted up (1
~ 4 times) or not.

If it is determined in step S249 that the number of coincidences has not been counted up (that is, the number of coincidences is 0), the process proceeds to the fine adjustment stage (flowchart shown in FIG. 9) in step S251. It should be noted that if the process returns to the confirmation of the link light of the optical communication in step S101 of FIG. 3 after the fine adjustment step of step S251 is completed, it is determined again whether the optical communication link is established. Then, the optical axis adjusting method can be selected.

If it is determined in step S247 that the number of coincidences is more than half of the number of transmissions (5 to 9 times), it is determined in step S253 whether the number of non-coincidences is 0 or not. If the number of times of disagreement is 0 in step S253, the optical axes are not perfectly aligned but the communication is performed almost accurately, or the optical line is congested and collisions between packets occur frequently, but communication is not performed. Since it is considered that the optical communication is correctly performed, it is considered that the optical communication link is established in step S255. Also, step S253
If the number of times of disagreement is not 0, it is considered that accurate communication cannot be performed because the optical axis is displaced. Therefore, in step S257, the process proceeds to the fine adjustment stage (flowchart shown in FIG. 9). Note that it is preferable to return to the confirmation of the link light of the optical communication in step S101 of FIG. 3 again after the fine adjustment stage is completed.

If it is determined in step S249 that the number of times of coincidence is counted up (1 to 4 times), it is determined in step S259 whether or not the number of times of disagreement is zero. If the number of mismatches is 0 in step S259, it is considered difficult to determine whether the optical axis is accurately determined and the optical communication link is established, and the number of transmissions, the number of matchings, the number of non-detections, and the mismatch Initialize the counter such as the number of times and start again (step S101 in FIG. 3).
Return to and repeat the process. If the number of times of disagreement is not 0 in step S259, the process proceeds to the step of fine adjustment (flowchart shown in FIG. 9) in step S261. Note that it is preferable to return to the confirmation of the link light of the optical communication in step S101 of FIG. 3 again after the fine adjustment stage is completed.

As described above, in the second embodiment, the first
In comparison with the embodiment described above, the test packet 30 is transmitted a plurality of times when the confirmation of the link light is obtained, and the most appropriate optical axis adjustment method is selected according to the response result and the collation result. As a result, it is possible to grasp the state of the optical communication link more accurately and immediately perform appropriate optical axis alignment without performing unnecessary steps, and it is possible to reduce the time spent for optical axis alignment. Becomes Moreover, since the optical axis alignment is performed using the result of the response of the optical wireless collection and delivery device 20,
It is possible to correctly align both the upstream optical axis and the downstream optical axis so that optical communication can be performed normally.

FIG. 11 shows a summary of the above first and second embodiments. FIG. 11 is a table showing selected optical axis adjustment methods and their selection conditions in the first and second embodiments of the optical axis adjustment method of the present invention. As described above, it is possible to consider various conditions and select the optimum optical axis adjusting method for the condition. Further, in the first and second embodiments, it is possible to set any appropriate value as the first and second threshold values. Also,
Although the number of times the test packet 30 is transmitted is 10 in the second embodiment, it is possible to select and set an appropriate number of times as appropriate.

[0056]

As described above, according to the present invention, the optical wireless communication terminal transmits a test packet to the optical wireless communication device, and the result of the response from the optical wireless communication device to the test packet is displayed. Accordingly, any one of a plurality of optical axis adjusting methods with different matching accuracy between the transmitting side and the receiving side optical axes is selected and executed so that transmission / reception can be executed. It is possible to shorten the time spent for the optical axis alignment by immediately performing the optical axis alignment suitable for the optical wireless link state of the optical wireless communication terminal without performing the above. In addition, especially when the optical axis adjusting method with a rough accuracy is performed, if the optical receiving means of the optical wireless communication terminal happens to be in the direction in which communication is possible, the optical axis alignment is immediately terminated and the optical axis is adjusted. Communication is possible and effective. Further, since the optical axis alignment is performed using the result of the response from the optical wireless concentrator, it is possible to accurately align both the upstream optical axis and the downstream optical axis so that the optical communication can be normally performed.

Further, according to the present invention, the optical wireless communication terminal transmits the test packet to the optical wireless collecting and delivering apparatus a plurality of times, and the optical wireless collecting and delivering apparatus responds to the plurality of test packets a plurality of times. Results are accumulated, and according to the accumulated result, one of a plurality of optical axis adjusting methods having different matching accuracy between the transmitting side and the receiving side optical axes is selected and executed so that transmission and reception can be performed. Therefore, it is possible to reduce the time spent for optical axis alignment by immediately performing optical axis alignment suitable for the optical wireless link state of the optical wireless communication terminal without performing unnecessary steps. Become. In addition, especially when the optical axis adjusting method with a rough accuracy is performed, if the optical receiving means of the optical wireless communication terminal happens to be in the direction in which communication is possible, the optical axis alignment is immediately terminated and the optical axis is adjusted. Communication is possible and effective. Further, since the optical axis alignment is performed using the result of the response of the optical wireless concentrator, it is possible to accurately align both the upstream optical axis and the downstream optical axis so that the optical communication can be normally performed.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration example of an optical wireless communication terminal used in the present invention.

FIG. 2 is a block diagram showing a configuration example of an optical wireless collecting and distributing apparatus used in the present invention.

FIG. 3 is a first page of a flowchart for explaining the first and second embodiments of the optical axis adjusting method in the optical wireless communication terminal of the present invention.

FIG. 4 is the second page of the flowchart for explaining the first embodiment of the optical axis adjusting method in the optical wireless communication terminal of the present invention.

FIG. 5 is the second page of the flowchart for explaining the second embodiment of the optical axis adjusting method in the optical wireless communication terminal of the present invention.

FIG. 6 is the third page of the flowchart for explaining the second embodiment of the optical axis adjusting method in the optical wireless communication terminal of the present invention.

FIG. 7 is a flow chart for explaining a step of coarse adjustment 1 in the optical axis adjusting method common to the prior art and the present invention.

FIG. 8 is a flow chart for explaining a stage of coarse adjustment 2 in the optical axis adjusting method common to the prior art and the present invention.

FIG. 9 is a flowchart for explaining a fine adjustment step in a conventional optical axis adjustment method common to the present invention.

FIG. 10 is a schematic diagram showing an example of a structure of a test packet and a communication frame.

FIG. 11 is a table showing selected optical axis adjustment methods and their selection conditions in the first and second embodiments of the optical axis adjustment method of the present invention.

FIG. 12 is a flowchart showing an example of a conventional optical axis adjusting method.

FIG. 13 is a schematic diagram showing a light receiving intensity region of a light receiving unit of an optical wireless communication terminal.

FIG. 14 is a schematic diagram showing an example of the locus of the light source at the steps of coarse adjustment 1 and coarse adjustment 2 of the conventional optical axis adjustment method.

FIG. 15 is a schematic diagram of a PD (Photo Detector) that is divided into four cells used for an optical receiving unit.

FIG. 16 is a schematic diagram showing an example of a locus of received light in a fine adjustment stage.

[Explanation of symbols]

10 Optical wireless communication terminal 11,25 Receiving means 12, 22 Communication data processing means 13, 23 Optical communication procedure processing means 14, 26 Optical transmission means 15, 21 Optical receiving means 16, 24 Transmission means 17 Pilot light extraction means 18 Optical axis alignment control means 19 Servo means 20 Optical wireless collection and delivery device 27 Pilot light generating means 28 Pilot light transmitting means 30 test packets 40 PD (photo detector)

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Katsuo Okuaki             3-12 Moriya-cho, Kanagawa-ku, Yokohama-shi, Kanagawa             Local Victor Company of Japan, Ltd. F-term (reference) 5K002 AA01 AA03 BA14 DA05 FA04

Claims (2)

[Claims] 1. An optical transmitter / receiver that transmits and receives the data by the optical wireless signal to and from an optical wireless concentrator that collects and delivers the data by the optical wireless signal, and that can perform the transmission and reception. In an optical axis adjusting method in an optical wireless communication terminal capable of executing a plurality of optical axis adjusting methods with different matching accuracy between axes, a step of transmitting a test packet to the optical wireless collecting and delivering apparatus, the test packet And a step of selecting and executing any one of the plurality of optical axis adjusting methods according to a result of a response from the optical wireless collecting and delivering apparatus to the optical axis in the optical wireless communication terminal. Adjustment method. 2. A transmitting side and a receiving side light for transmitting and receiving the data by the optical wireless signal to and from the optical wireless concentrator for collecting and delivering the data by the optical wireless signal, and enabling the transmission and reception. In an optical axis adjusting method in an optical wireless communication terminal capable of executing a plurality of optical axis adjusting methods with different matching accuracy between axes, a step of transmitting a test packet to the optical wireless collecting and delivering apparatus a plurality of times, Any one of the plurality of optical axis adjusting methods according to a step of accumulating results of a plurality of times of responses from the optical wireless concentrator to each of a plurality of test packets, and a cumulative result of the accumulating step. And a step of executing the optical axis adjustment method in an optical wireless communication terminal.