JPH09107329A - Data communication method and data communication equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain a high data transmission speed and attain the n to n simultaneous multiplex communication by decreasing an emission spread angle of a transmitter and selecting a spread area to be set in the vicinity of a receiver. SOLUTION: A transmitter 11A emits an infrared ray 12A at a narrow emission spread angle 15A to a spread area 13A, and the infrared ray 12A spread at the area 13A is received by a receiver 14A. A transmitter 11B emits an infrared ray 12B at a narrow emission spread angle 15B to a spread area 13B, and the infrared ray 12B spread at the area 13B is received by a receiver 14B. In this case, the positions of the areas 13A, 13B are set differently in the vicinity of the receivers 14A, 14B so that the probability of incidence of the spread infrared rays 12A, 12B into the receivers 14A, 14B is changed. Interference between two sets of communication systems is decreased by decreasing the emission spread angle of the transmitter and placing the spread area in the vicinity of the receiver in this way so as to attain a high transmission speed and to attain the n to n simultaneous multiplex communication.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data communication method and device used for data communication between computer terminals, for example. In particular, the present invention relates to a wireless data communication method and apparatus using an electromagnetic wave (for example, infrared ray) having a frequency higher than a millimeter wave as a carrier wave.

[0002]

2. Description of the Related Art FIG. 4 shows a conventional data communication method using infrared diffusion. In this data communication method, the infrared rays 43 emitted from the transmission device 41 at the emission divergence angle 46 are transmitted to the wall and
The infrared ray 44 irradiated on the ceiling 45 and reflected or diffused there is received by the receiving device 42 having a wide incident divergence angle 47, and data is communicated by modulating the infrared ray by various methods.

In this configuration, the transmitter 41 and the receiver 4
No complete line of sight is required between the two and even if there is an obstacle on the line of sight, data communication will not be hindered. Therefore, it is not necessary to align the devices, and the device can be applied to a mobile terminal such as a mobile terminal that is frequently moved.

[0004]

However, in the conventional data communication method shown in FIG. 4, a transmitter 41 and a receiver 42 are provided.
The optical path of infrared rays formed between
6. There are many depending on the incident divergence angle 47 and the state of reflection or diffusion on the wall / ceiling 45. Along with this, the receiving device 42 receives a plurality of infrared rays having a delay time proportional to the difference between the optical path lengths, such as the optical path 48 and the optical path 49. The effect of such multi-path is that the infrared ray having the next data cannot be received until the infrared ray that has passed the longest optical path is received by the receiving device 42 with the latest delay. Therefore, there is a problem that the data transmission speed becomes low.

Further, since the outgoing divergence angle 46 of the transmitting device 41 is wide and the transmitted infrared light is spread over a wide area, the amount of infrared light that can be received by the receiving device 42 is reduced, and S
This leads to a decrease in the / N ratio. The decrease in the S / N ratio causes an increase in the error rate of received data if the data transmission rate is constant,
Reliability decreases. On the other hand, in order to keep the data error rate at a constant level, the data transmission rate had to be kept low.

Further, since the incident divergence angle 47 of the receiver 42 is wide, it is easy to receive ambient light such as illumination light and sunlight, and shot noise increases. In order to avoid the effect of this shot noise, the data transmission rate had to be kept low. Thus, the exit divergence angle 46
By increasing the incident divergence angle 47, it is not necessary to position each device for communication to face each other, but improvement of the S / N ratio, measures against multipath, and measures against shot noise have become new issues. . Furthermore, the exit spread angle is 4
Since 6 is wide, 1 to n broadcast communication is possible, but since the incident divergence angle 47 is also wide, it is difficult to perform n to n simultaneous multiplex communication. Therefore, the n-to-n multiplex communication must be performed by the time division method, which has a drawback that the data transmission rate becomes slow.

The present invention relates to a method and apparatus for wireless data communication performed between computer terminals, wherein n
An object of the present invention is to enable simultaneous multiplex communication for pair n, reduce mutual interference between communication signals, and increase the data transmission speed.

[0008]

SUMMARY OF THE INVENTION The present invention is a data communication method and apparatus that uses as a carrier wave an electromagnetic wave having a frequency higher than a millimeter wave and having a high linearity, and the transmitting apparatus adjusts the emission direction of the electromagnetic wave to the position of the receiving apparatus. At the time of adjustment, the emission spread angle of the electromagnetic wave is narrowed and the electromagnetic wave is applied to a curved surface (diffusion region) such as a ceiling having a diffusive property at a position close to the receiving device. The receiving device can efficiently use the energy of the electromagnetic wave by receiving the electromagnetic wave diffused there, and can relieve the alignment of the transmitting / receiving device as compared with the case of directly receiving the electromagnetic wave without diffusing it, and the influence of obstacles etc. It can be avoided.

Further, by narrowing the outgoing spread angle of the electromagnetic wave, it is possible to suppress the influence of multipath, which is one of the limiting factors of the data transmission rate, to a low level. Further, since the diffusion area of the electromagnetic wave is set at a position close to the receiving device in terms of distance, the incident spread angle of the receiving device can be narrowed. This makes it difficult to receive surrounding electromagnetic waves due to, for example, lighting or the sun, so that the effect of shot noise can be suppressed to a low level and the data transmission rate can be increased.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION In the following description, an example in which infrared rays are used as electromagnetic waves having a frequency higher than a millimeter wave and having a high linearity is shown, but it is not necessarily limited to infrared rays. FIG. 1 shows an embodiment of the data communication method and apparatus of the present invention. In the figure, 10 is a curved surface on which infrared rays are diffused. The transmitter 11 narrows the outgoing divergence angle of the infrared rays 12 and sets the direction of the diffusion region 13 which is close in distance from the receiver 14 to irradiate the electromagnetic waves.

In the diffusion area 13, infrared rays are diffused at a wide angle. Therefore, the amount of infrared light that can be received by the receiving device 14 rapidly decreases as the diffusion region 13 moves away from the receiving device 14. Here, as shown in FIG. 2 (a), the horizontal distance between the diffusion region 13 and the receiver 14 is x, and an example of calculation of the light receiving efficiency when x is changed is shown in FIG. 2 (b). The calculation condition is that the distance between the transmission device 11 and the reception device 14 is 5 m, and x changes during this period. The height of the diffusion region 13 was 1.3 m. As shown here,
It can be seen that the light receiving efficiency significantly decreases as the diffusion region 13 moves away from the receiving device 14.

In the present invention, the diffusion area 13 and the receiving device 14 are provided.
The emission directions of the infrared rays transmitted from the transmission device 11 are set so that they are closer in distance. As a result, the receiving device 14
It is possible to improve the light receiving efficiency.

[0013]

FIG. 3 shows an embodiment of the data communication method and apparatus of the present invention. In the figure, 10 is a curved surface on which infrared rays are diffused. Here, the transmitter 11A and the receiver 14
A, the transmitter 11B and the receiver 14B communicate with each other. The transmitter 11A irradiates the diffusion area 13A with the infrared rays 12A emitted at a narrow emission divergence angle 15A, and causes the infrared rays 12a diffused in the diffusion area 13A to enter the reception apparatus 14A. The transmitter 11B has a narrow exit divergence angle 15
Irradiate the infrared rays 12B emitted in B to the diffusion area 13B,
The receiving device 14 receives the infrared rays 12b diffused in the diffusion area 13B.
It is incident on B. At this time, by making the positions of the diffusion regions 13A and 13B different and arranging them in the vicinity of the receiving devices 14A and 14B, respectively, the diffusion regions 13A and 13B are arranged.
It is possible to reduce the probability that the infrared rays 12a and 12b diffused by B enter the receiving devices 14B and 14A on the opposite sides, respectively. That is, mutual interference between two sets of communication can be reduced.

In the receivers 14A and 14B,
By narrowing the incident divergence angles 16A and 16B, it is possible to further reduce the probability that the infrared rays 12a and 12b diffused in the diffusion regions 13A and 13B are incident on the receiving devices 14B and 14A on the opposite sides, respectively. That is, mutual interference between two sets of communication can be further reduced. Also, the above is the same even if the number of communication sets increases, and by changing the area where infrared rays are diffused,
It is possible to perform n-to-n simultaneous multiplex communication without interfering with each other. As a result, it is not necessary to reduce the data transmission rate even when the number of multiplexed signals increases, and it is possible to increase the data transmission rate in n to n simultaneous multiplex communication.

Hereinafter, in the transmitter 11, the diffusion area 1
3 shows a method of setting the emission direction of infrared rays so that the reception device 14 and the reception device 14 are close to each other in distance. When the transmitting device 11 and the receiving device 14 are almost in the fixed state, the receiving device 14 and the corresponding diffusion area 1 on the transmitting device 11 side.
The position of 3 is confirmed, and the emission direction of infrared rays is manually set to the diffusion region 13.

When the transmitter 11 and the receiver 14 frequently move, first the transmitter 11 to the receiver 14 are moved.
, A request signal requesting that infrared rays indicating the position be emitted. Receiving device 14 that has received this request signal
Emits infrared rays having a predetermined wavelength or infrared rays having a predetermined code, for example. The transmitting device 11 receives the infrared light emitted from the receiving device 14 and grasps the position thereof by using a combination of a position detection photodiode (PSD), a two-dimensional arrayed photodiode array and the like, and a lens. The corresponding diffusion area 13 is determined based on the position information, and the emission direction of infrared rays is determined.

A method for setting the emission direction of infrared rays is described in Japanese Patent Laid-Open No. 7-143063 (data communication method and data communication device), in which a drive device holding a transmitter controls the emission direction. Alternatively, a configuration in which the driving device holds the mirror and the infrared reflection direction is controlled by the angle of the mirror can be used. Further, the method of narrowing the exit divergence angle 15 and the entrance divergence angle 16 is realized by the configuration described in the publication, in which light is condensed using a lens or a concave mirror.

[0018]

As described above, the data communication method and apparatus of the present invention reduces the emission spread angle of the transmitter,
In addition, by making the diffusion region near the receiving device, it is possible to use electromagnetic waves efficiently and reduce mutual interference between a plurality of communication signals. As a result, the data transmission speed can be increased, and n to n simultaneous multiplex communication can be enabled.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of a data communication method and device of the present invention.

FIG. 2 is a diagram showing a relationship between a receiving device and a spreading area in the data communication method and device of the present invention.

FIG. 3 is a diagram showing an embodiment of a data communication method and device of the present invention.

FIG. 4 is a diagram showing a conventional data communication method using infrared diffusion.

[Explanation of symbols]

 10 Curved surface where infrared rays are diffused 11 Transmitter 12 Infrared 13 Diffusion area 14 Receiver 15 Exit spread angle 16 Entrance spread angle

Claims (2)

[Claims] 1. A transmitting device and a receiving device wirelessly transmit and receive an electromagnetic wave carrying communication data on a carrier wave having a frequency higher than a millimeter wave, in a space surrounded at least in part by a curved surface of a material that generates a diffuse wave. In the data communication method, the transmitting device narrows the outgoing divergence angle of the electromagnetic wave to be transmitted to each receiving device, and irradiates the electromagnetic wave to a diffusion area on a curved surface that is close in distance from the receiving device of the transmission destination. Data communication method. 2. An electromagnetic wave comprising at least a transmitter and a receiver arranged in a space surrounded by a curved surface of a material that generates a diffuse wave, and carrying communication data on a carrier wave having a frequency higher than a millimeter wave. In the data communication device for transmitting / receiving, the transmitting device narrows the outgoing divergence angle of the electromagnetic wave, and sets a means for setting the outgoing direction of the electromagnetic wave in a diffusion region on a curved surface that is close in distance from the receiving device of the transmission destination. A data communication device provided with.