JP7741518B2 - Transmitter, receiver, communication system, and method for acquiring positioning information - Google Patents

Description

The present invention relates to a transmitter, a receiver, a communication system, and a method for obtaining positioning information.

Currently, competing high-speed wireless communication methods include those using millimeter waves or terahertz waves as carriers, and those using infrared light as a carrier (for example, free space optics (FSO)). Terahertz waves, in particular, operate in the frequency band from approximately 100 GHz to 10 THz, a frequency band not allocated by the Radio Law. Therefore, with their high carrier frequency and wide frequency band, they are expected to be applicable to high-speed wireless communication.

Radio waves (light waves) have the property that they tend to propagate in a more directional manner as the carrier frequency increases. Therefore, using a high-frequency carrier with a narrow beam width, such as FSO, can reduce the risk of signals being received by unintended or malicious users during propagation. While using high-frequency signals is effective from the perspective of increasing security, they are susceptible to the effects of scintillation and atmospheric dispersion and are not suitable for transmitting wideband signals (high-speed signal transmission). For this reason, communication methods using millimeter waves or terahertz waves are preferred for wideband signal transmission.

Tadao Nagatsuma, "Ultra-high-speed wireless communication opened up by terahertz waves", Journal of the Japan Society for Precision Engineering Vol.82, No.3, 2016

However, with millimeter waves or terahertz waves, the beam's arrival position cannot be visually confirmed like with FSO, which utilizes the visibility of visible light, and this presents a problem in that positioning the transmitter and receiver (station placement design) is not easy. Because millimeter waves and terahertz waves tend to travel in a straight line, unless the transmitter and receiver are positioned with high precision, deviation of the beam from the receiving surface can lead to a decrease in reception sensitivity.

In light of the above circumstances, the present invention aims to provide technology that makes it possible to easily position transmitters and receivers in communications using high-frequency bands such as millimeter waves or terahertz waves.

One aspect of the present invention is a transmitter comprising a transmitting unit that transmits millimeter-wave or terahertz-wave radio waves via an antenna, a light source that outputs light waves of one or more wavelengths, and a reflecting unit that transmits the radio waves and the light waves of one or more wavelengths coaxially.

One aspect of the present invention is a receiver comprising: a focusing lens that focuses light waves of one or more wavelengths transmitted from a transmitter; an antenna that receives at least radio waves transmitted coaxially with the light waves of one or more wavelengths transmitted from the transmitter; and a receiving unit that receives the light waves of one or more wavelengths either upstream or downstream of the antenna.

One aspect of the present invention is a communications system comprising a transmitter and a receiver. The transmitter comprises: a transmitting unit that transmits millimeter-wave or terahertz radio waves via an antenna; a light source that outputs light waves of one or more wavelengths; a reflecting unit that is installed coaxially with the antenna and reflects the light waves of the one or more wavelengths output from the light source, thereby transmitting the radio waves and the light waves of the one or more wavelengths on the same axis; and an acquiring unit that receives light waves reflected from the receiver via the reflecting unit and acquires a current value, a voltage value, or light intensity based on the received light waves. The receiver comprises: a first reflecting unit that reflects the light waves of the one or more wavelengths from the light waves of the one or more wavelengths and the radio waves transmitted coaxially from the transmitter; and a second reflecting unit that reflects at least one of the light waves of the one or more wavelengths reflected by the first reflecting unit. This communications system is characterized in that the first reflecting unit reflects the light waves of the one wavelength reflected by the second reflecting unit back to the transmitter.

One aspect of the present invention is a method for acquiring positioning information between a transmitter and a receiver in a communication system including the transmitter and receiver, in which the transmitter transmits millimeter wave or terahertz radio waves via an antenna, outputs light waves of one or more wavelengths, and reflects the light waves of the one or more wavelengths to transmit the radio waves and the light waves of the one or more wavelengths on a coaxial line, receives the light waves reflected from the receiver, and acquires a current value, a voltage value, or an optical intensity based on the received light waves, and the receiver reflects the light waves of the one or more wavelengths from the light waves of the one or more wavelengths and the radio waves transmitted on the coaxial line from the transmitter, reflects at least one light wave of the one or more wavelengths from the reflected light waves of the one or more wavelengths, and reflects the light waves of the one wavelength back to the transmitter.

This invention makes it possible to easily position transmitters and receivers in communications using high-frequency bands such as millimeter waves or terahertz waves.

FIG. 1 is a diagram illustrating an example of the configuration of a communication system according to a first embodiment. FIG. 10 is a diagram illustrating another configuration example (part 1) of the transmitter according to the first embodiment. FIG. 10 is a diagram illustrating another configuration example (part 2) of the transmitter according to the first embodiment. FIG. 10 is a diagram illustrating another configuration example (part 3) of the transmitter according to the first embodiment. FIG. 10 is a diagram illustrating another configuration example (part 4) of the transmitter according to the first embodiment. FIG. 10 is a diagram illustrating another configuration example (part 1) of the receiver according to the first embodiment. FIG. 10 is a diagram illustrating another configuration example (part 2) of the receiver according to the first embodiment. FIG. 10 is a diagram illustrating another configuration example (part 3) of the receiver according to the first embodiment. FIG. 4 is a sequence diagram showing the flow of a process for determining installation locations of a transmitter and a receiver in the communication system according to the first embodiment. FIG. 10 is a diagram illustrating an example of the configuration of a communication system according to a second embodiment. FIG. 10 is a diagram illustrating an example of the configuration of a communication system according to a second modification of the second embodiment. FIG. 10 is a diagram illustrating a configuration example of a communication system according to a third modified example of the second embodiment. FIG. 10 is a diagram illustrating an example of the configuration of a communication system according to a fourth modified example of the second embodiment.

One embodiment of the present invention will be described below with reference to the drawings.

(First embodiment)
1 is a diagram showing an example of the configuration of a communication system 100 according to the first embodiment. The communication system 100 includes a transmitter 10 and a receiver 20. In the communication system 100, in order to perform communication between the transmitter 10 and the receiver 20, it is necessary to determine the installation positions of the transmitter 10 and the receiver 20 in advance. Determining the installation positions of the transmitter 10 and the receiver 20 means determining the position of the antenna of the transmitter 10 and the position of the antenna of the receiver 20. The transmitter 10 and the receiver 20 include a configuration for determining their installation positions.

To determine the installation position, the transmitter 10 has a reflecting medium that reflects light waves installed on the same axis as the antenna that outputs millimeter or terahertz radio waves. The transmitter 10 transmits millimeter or terahertz radio waves and light waves on the same axis.

To determine the installation position, the receiver 20 has a reflecting medium that reflects light waves installed coaxially with the antenna that receives the millimeter or terahertz radio waves. The receiver 20 receives the millimeter or terahertz radio waves with the antenna and receives the light waves reflected by the reflecting medium with an optical system. The installation position can be determined by installing an antenna that receives the millimeter or terahertz radio waves at the arrival position of the light waves. In addition to using light waves to position the antenna, similar effects can be achieved by transmitting or receiving a modulated signal as a carrier, and the transmission bandwidth in the same space can be expanded by combining wireless transmission and optical space transmission. Specific configuration examples of the transmitter 10 and receiver 20 are described below.

The transmitter 10 comprises a signal generating unit 101, a transmitting unit 102, an antenna 103, a light source 104, an optical fiber 105, a collimator lens 106, and a reflection medium 107. The light source 104, the optical fiber 105, the collimator lens 106, and the reflection medium 107 provided in the transmitter 10 are devices used to determine the position of the transmitter (hereinafter referred to as the "transmitter positioning device"). The transmitter positioning device does not have to be provided inside the transmitter 10, but may be provided externally. Providing the transmitter positioning device externally makes it easier to remove the transmitter 10 after the positioning has been determined.

The signal generation unit 101 generates a signal to be transmitted as radio waves.

The transmitter 102 transmits the signal generated by the signal generator 101 via the antenna 103 as millimeter wave or terahertz wave radio waves.

Light source 104 outputs light waves.

The optical fiber 105 connects the light source 104 and the collimator lens 106, and inputs the light output from the light source 104 into the collimator lens 106.

The collimator lens 106 collimates the light waves input via the optical fiber 105 and outputs them.

The reflection medium 107 is installed coaxially with the antenna 103 and in a position and orientation that allows it to reflect the light waves output from the collimator lens 106 to the receiver 20. The reflection medium 107 reflects the light waves output from the collimator lens 106. The reflection medium 107 is, for example, a reflection mirror made of a polarizing plate or a polymer thin film. The reflection medium 107 is one aspect of the reflection section.

The receiver 20 comprises a condenser lens 201, a reflection medium 202, an antenna 203, and a collimator lens 204. The condenser lens 201, reflection medium 202, and collimator lens 204 of the receiver 20 are devices used to determine the position of the receiver (hereinafter referred to as the "receiving side positioning device"). The receiving side positioning device does not have to be provided inside the receiver 20, but may be provided externally. Providing the receiving side positioning device externally makes it easier to remove the receiver 20 after the positioning has been determined.

The condenser lens 201 condenses the light waves output from the transmitter 10.

The reflection medium 202 is installed coaxially with the antenna 203, at a position and orientation that allows it to reflect the light waves focused by the focusing lens 201. If the transmitter 10 and receiver 20 are installed in the correct positions, the reflection medium 202 reflects the light waves focused by the focusing lens 201 toward the collimator lens 204. Here, the correct installation positions for the transmitter 10 and receiver 20 are positions where the millimeter wave or terahertz wave radio waves transmitted from the transmitter 10 can be received with a receiving sensitivity above a threshold. The reflection medium 202 is one aspect of the first reflector.

Antenna 203 receives millimeter waves or terahertz waves transmitted from transmitter 10.

The collimator lens 204 collimates the light waves reflected by the reflection medium 202 and outputs them to the optical fiber. If light waves are obtained through the collimator lens 204 and the optical fiber, the installation positions of the transmitter 10 and receiver 20 can be considered correct.

In the above example, the transmitter 10 is configured to combine millimeter or terahertz radio waves with light waves using an optical fiber 105 and a collimator lens 106. However, the same effect can be achieved by installing an LD (Laser Diode) and a collimator lens and combining millimeter and terahertz waves using a spatial optical system.

Next, other configurations of the transmitter 10 will be described using Figures 2 to 5. Figure 2 is a diagram showing another example (part 1) of the configuration of the transmitter in the first embodiment. As shown in Figure 2, the transmitter 10a includes a signal generating unit 101, a transmitting unit 102, an antenna 103, a light source 104, an optical fiber 105, a collimator lens 106, and a reflection medium 107a. Note that the light source 104, the optical fiber 105, the collimator lens 106, and the reflection medium 107a included in the transmitter 10a are transmission-side positioning devices, and may be provided externally rather than internally to the transmitter 10a. The transmitter 10a differs in configuration from the transmitter 10 in that it includes the reflection medium 107a instead of the reflection medium 107. The other configurations of the transmitter 10a are similar to those of the transmitter 10. The differences from the transmitter 10 will be described below.

Reflection medium 107a is a compact medium that is smaller in size than reflection medium 107 shown in Figure 1. Apart from its size, it is otherwise similar to reflection medium 107. By making the medium that reflects light waves smaller in this way, it is possible to reduce the effects of diffraction of radio waves. Reflection medium 107a is one form of reflection section.

Figure 3 is a diagram showing another example (part 2) of the configuration of the transmitter in the first embodiment. As shown in Figure 3, transmitter 10b includes a signal generating unit 101, a transmitting unit 102, an antenna 103, a light source 104, an optical fiber 105, a collimator lens 106, a reflection medium 107, and a lens 108. Note that light source 104, optical fiber 105, collimator lens 106, reflection medium 107, and lens 108 included in transmitter 10b are transmission-side positioning devices, and may be provided externally rather than internally to transmitter 10b. Transmitter 10b differs in configuration from transmitter 10 in that it additionally includes lens 108. The rest of the configuration of transmitter 10b is similar to that of transmitter 10. The differences from transmitter 10 are described below.

Lens 108 is a lens (e.g., a cylindrical lens) used to collimate millimeter or terahertz radio waves, for example, when propagating over long distances. By further providing lens 108, radio waves can be converted into a parallel beam. The reflection medium 107 in transmitter 10b may be reflection medium 107a. Transmitter 10b shown in FIG. 3 thus transmits millimeter or terahertz radio waves and light waves coaxially by reflecting the light waves output from collimator lens 106 with reflection medium 107 and converting the radio waves output from antenna 103 into a parallel beam with lens 108.

Figure 4 is a diagram showing another example (part 3) of the transmitter configuration in the first embodiment. As shown in Figure 4, transmitter 10c includes a signal generating unit 101, a transmitting unit 102, an antenna 103, a light source 104, an optical fiber 105, a collimator lens 106, a reflection medium 107, and a parabolic mirror 109. The light source 104, optical fiber 105, collimator lens 106, reflection medium 107, and parabolic mirror 109 included in transmitter 10c are transmitter-side positioning devices, and may be provided externally rather than internally. Transmitter 10c differs from transmitter 10 in that it newly includes a parabolic mirror 109. The remaining configuration of transmitter 10c is similar to that of transmitter 10. The differences from transmitter 10 are described below. The configuration of transmitter 10c shown in Figure 4 is used when transmitter 10c and receiver 20 are not positioned facing each other.

The parabolic mirror 109 is a type of concave mirror, a parabolic mirror whose interior is a parabolic body of revolution. The parabolic mirror 109 is installed opposite the reflective medium 107 and changes the direction of the light waves and radio waves reflected by the reflective medium 107. In this case, millimeter wave or terahertz wave radio waves and light waves are transmitted coaxially. If the receiver 20 is located laterally of the transmitter 10c, the parabolic mirror 109 is installed in a direction that changes the direction of the light waves reflected by the reflective medium 107 laterally. In this way, by changing the optical path using the parabolic mirror 109, the installation position can be determined even if the transmitter 10c and receiver 20 are not positioned opposite each other. Note that the reflective medium 107 in the transmitter 10c may be the reflective medium 107a. The parabolic mirror 109 is one aspect of the reflecting section.

The transmitter 10c shown in Figure 4 reflects the light waves output from the collimator lens 106 using a reflection medium 107, and then changes the direction of the light waves reflected by the reflection medium 107 and the radio waves output from the antenna 103 using a parabolic mirror 109, thereby transmitting millimeter wave or terahertz wave radio waves and light waves coaxially.

Figure 5 is a diagram showing another example (part 4) of the transmitter configuration in the first embodiment. As shown in Figure 5, transmitter 10d includes a signal generating unit 101, a transmitting unit 102, an antenna 103, a light source 104, an optical fiber 105, a collimator lens 106, a lens 108, a parabolic mirror 109, a circulator 110, and an optical receiving unit 111. The light source 104, optical fiber 105, collimator lens 106, a lens 108, a parabolic mirror 109, a circulator 110, and an optical receiving unit 111 included in transmitter 10d are transmitter-side positioning devices, and may be provided externally rather than internally. Transmitter 10d is an expanded version of transmitter 10c, with an opening provided in parabolic mirror 109 from which light waves are output. Therefore, transmitter 10d does not need to include a reflective medium 107.

The circulator 110 has a first port, a second port, and a third port. The first port of the circulator 110 is connected to the light source 104. The second port of the circulator 110 is connected to the collimator lens 106 via an optical fiber 105. The third port of the circulator 110 is connected to the optical receiving unit 111. An optical signal input to the first port is output from the second port. An optical signal input to the second port is output from the third port. An optical signal input to the third port is output from the first port.

For example, light waves output from the light source 104 are input to the first port of the circulator 110. The light waves input to the first port of the circulator 110 are output from the second port. For example, light waves reflected from the receiver 20 are input to the second port of the circulator 110. The light waves input to the second port of the circulator 110 are output from the third port.

The optical receiving unit 111 receives the light waves output from the third port of the circulator 110. The optical receiving unit 111 is, for example, a light receiver or a power meter. If the optical receiving unit 111 is a light receiver, the optical receiving unit 111 converts the received light waves into an electrical signal and obtains a current value or voltage value. If the optical receiving unit 111 is a power meter, the optical receiving unit 111 obtains the light intensity of the received light waves.

As shown in FIG. 5, an opening is provided in a portion of the parabolic mirror 109. A collimator lens 106 is installed in the opening of the parabolic mirror 109. Light waves output from the light source 104 are output from the collimator lens 106 via the optical fiber 105. The light waves collimated by the collimator lens 106 are output from the opening of the parabolic mirror 109. Furthermore, the radio waves output from the antenna 103 are redirected by the parabolic mirror 109, converted into a parallel beam by the lens 108, and propagated in the same direction as the light waves. In this way, the transmitter 10d shown in FIG. 5 coaxially transmits the light waves output from the collimator lens 106 installed in the opening of the parabolic mirror 109 and millimeter wave or terahertz wave radio waves by redirecting the radio waves output from the antenna 103 in the parabolic mirror 109 to the same direction as the light wave propagation and then converting the radio waves into a parallel beam by the lens 108. When configured in this manner, there is no need to place the reflective medium 107 in the path of radio wave propagation, reducing the number of parts and mitigating the effects of diffraction.

Next, other configurations of the receiver 20 will be described using Figures 6 to 8. Figure 6 is a diagram showing another example configuration (part 1) of the receiver in the first embodiment. As shown in Figure 6, the receiver 20a includes a condenser lens 201, a reflection medium 202, an antenna 203, and a photoreceiver 205. Note that the condenser lens 201, reflection medium 202, and photoreceiver 205 included in the receiver 20a are receiver-side positioning devices, and may be provided externally rather than internally. The receiver 20a differs in configuration from the receiver 20 in that it includes a photoreceiver 205 instead of a collimator lens 204. The other configurations of the receiver 20a are similar to those of the receiver 20. The differences from the receiver 20 will be described below.

The optical receiver 205 receives the light waves reflected by the reflection medium 202. For example, the optical receiver 205 is a photodiode. The optical receiver 205 converts the received light waves into an electrical signal and outputs a current or voltage value. If the current or voltage value obtained by the optical receiver 205 is equal to or greater than a threshold value, it means that stronger light has been received, and the installation positions of the transmitter 10 and receiver 20a can be considered correct. Therefore, the position where the current or voltage value obtained by the optical receiver 205 is equal to or greater than the threshold value can be determined to be the installation position of the receiver 20a. This makes it easy to position the transmitter and receiver in communications using high-frequency bands such as millimeter waves or terahertz waves.

Figure 7 is a diagram showing another example (part 2) of the receiver configuration in the first embodiment. As shown in Figure 7, receiver 20b includes a condenser lens 201, an antenna 203, and an optical receiving element 206. Note that the condenser lens 201 and optical receiving element 206 included in receiver 20b are receiver-side positioning devices, and may be provided externally rather than internally. Receiver 20b differs from receiver 20 in that it does not include a reflective medium 202 or a collimator lens 204, and that it newly includes an optical receiving element 206. The rest of the configuration of receiver 20b is similar to that of receiver 20. The differences from receiver 20 are described below.

The optical receiving element 206 is connected to the antenna 203 and receives light waves propagating within the antenna 203. For example, the optical receiving element 206 is a photodiode. The optical receiving element 206 converts the received light waves into an electrical signal and outputs a current or voltage value. If the current or voltage value obtained by the optical receiving element 206 is equal to or greater than a threshold value, it means that stronger light has been received, and the installation positions of the transmitter 10 and receiver 20b can be considered correct. Therefore, the position where the current or voltage value obtained by the optical receiving element 206 is equal to or greater than the threshold value can be determined to be the installation position of the receiver 20b.

In this way, the receiver 20b shown in Figure 7 takes advantage of the fact that light waves can also propagate through the waveguide that is the antenna 203, and installs the optical receiving element 206 at the end point of the antenna 203 during positioning. The position of the antenna 203 can then be determined as the installation position for the receiver 20b so that the current or voltage value obtained from the optical receiving element 206 is maximized. This makes it easy to position the transmitter and receiver in communications using high-frequency bands such as millimeter waves or terahertz waves.

Figure 8 is a diagram showing another example (part 3) of the receiver configuration in the first embodiment. As shown in Figure 8, receiver 20c includes a condenser lens 201, an antenna 203, and an RF receiving element 207. Note that condenser lens 201 and RF receiving element 207 included in receiver 20c are receiver-side positioning devices, and may be provided externally rather than internally. Receiver 20c differs from receiver 20 in that it does not include a reflective medium 202 or a collimator lens 204, and that it newly includes an RF receiving element 207. The rest of the configuration of receiver 20c is similar to that of receiver 20. The differences from receiver 20 are described below.

The RF receiving element 207 is a receiving element made from a compound semiconductor. The RF receiving element 207 can detect even weak light. This allows it to receive radio waves and light waves simultaneously, which is expected to reduce the number of parts required.

The communication system 100 in the first embodiment may be configured by combining any one of the transmitters 10, 10a, 10b, 10c, and 10d shown in Figures 1 to 5 with any one of the receivers 20, 20a, 20b, and 20c shown in Figures 1, 6 to 8.

9 is a sequence diagram showing the flow of a process for determining the installation locations of the transmitter 10 and the receiver 20 in the communication system 100 according to the first embodiment. Note that the explanation of FIG. 9 will be given taking as an example a case where the transmitter 10 and the receiver 20 have the configuration shown in FIG. 1.
A user installing the transmitter 10 installs the transmitter 10 equipped with a transmitter positioning device at a candidate installation location (step S101). A user installing the receiver 20 installs the receiver 20 equipped with a receiver positioning device at a candidate installation location (step S102). The light source 104 of the transmitter 10 outputs a light wave (step S103). The light wave output by the light source 104 is input to the collimator lens 106 via the optical fiber 105. The collimator lens 106 converts the input light wave into a parallel light wave and outputs it to the reflection medium 107. The light wave output from the collimator lens 106 is reflected by the reflection medium 107.

The signal generation unit 101 generates a signal (step S104). The signal generation unit 101 outputs the generated signal to the transmission unit 102. The transmission unit 102 transmits the signal generated by the signal generation unit 101 via the antenna 103 as millimeter wave or terahertz wave radio waves (step S105). As a result, the radio waves and light waves output from the transmitter 10 are transmitted coaxially. If the receiver 20 is installed in the correct position for communicating with the transmitter 10, the receiver 20 can receive the radio waves and light waves transmitted from the transmitter 10. On the other hand, if the receiver 20 is not installed in the correct position for communicating with the transmitter 10, the receiver 20 cannot receive the radio waves and light waves transmitted from the transmitter 10.

The user installing the receiver 20 uses the light waves transmitted from the transmitter 10 as a marker and aligns the antenna 203 of the receiver 20 so that it is at a position where the light waves can be received (the arrival position of the light waves) (step S106). For example, the user installing the receiver 20 may determine that the position where an optical signal is output from the collimator lens 204 provided in the receiver 20 is the position where the light waves can be received. After alignment, the antenna 203 of the receiver 20 receives radio waves (step S107). The light waves are reflected by the reflective medium 202 and input to the collimator lens 204, where they are received (step S108).

The communication system 100 configured as described above makes it possible to easily position the transmitter and receiver in communications using high-frequency bands such as millimeter waves or terahertz waves. Specifically, in the transmitter 10, a reflecting medium 107 that reflects only light waves is installed along the propagation path of the radio waves, and millimeter waves and light waves are transmitted coaxially. In the receiver 20, taking advantage of the visibility and linearity of light waves, millimeter wave and terahertz wave antennas are installed at the arrival positions of the light waves using the light waves as markers. In this way, by transmitting millimeter or terahertz radio waves and light waves coaxially and utilizing the linearity and visibility of light waves, it becomes possible to easily position the transmitter and receiver in communications using high-frequency bands such as millimeter waves or terahertz waves.

Second Embodiment
In the first embodiment, a configuration was shown in which the position of the receiver is determined according to the light wave transmitted from the transmitter, thereby determining the positions of the transmitter and the receiver. In the second embodiment, a configuration will be described in which the receiver also determines the position on the transmitter side by reflecting the light wave transmitted from the transmitter.

Figure 10 is a diagram showing an example configuration of a communication system 200 in the second embodiment. The communication system 200 includes a transmitter 15 and a receiver 25. In the communication system 200, in order to communicate between the transmitter 15 and the receiver 25, it is necessary to determine the installation positions of the transmitter 15 and the receiver 25 in advance. The transmitter 15 and the receiver 25 are equipped with a configuration for determining their installation positions.

Transmitter 15 has the configuration of any of transmitters 10, 10a, 10b, 10c, and 10d in the first embodiment, and transmits millimeter-wave or terahertz-wave radio waves and light waves coaxially. Furthermore, transmitter 15 receives the light waves reflected by receiver 25.

To determine the installation position, the receiver 25 has a reflecting medium that reflects light waves installed coaxially with the antenna that receives the millimeter or terahertz radio waves. Furthermore, the receiver 25 receives the millimeter or terahertz radio waves with the antenna, and returns the light waves reflected by the reflecting medium to the transmitter 10 via a reflector. Specific configuration examples of the transmitter 15 and receiver 25 are described below.

Transmitter 15 comprises a signal generating unit 101, a transmitting unit 102, an antenna 103, a light source 104, an optical fiber 105, a collimator lens 106, a reflection medium 107, a circulator 110, and an optical receiving unit 111. The light source 104, optical fiber 105, collimator lens 106, reflection medium 107, circulator 110, and optical receiving unit 111 provided in transmitter 15 are transmitting-side positioning devices, and may be provided externally rather than internally. Transmitter 15 differs in configuration from transmitter 10 in that it additionally includes a circulator 110 and an optical receiving unit 111. The rest of the configuration of transmitter 15 is similar to that of transmitter 10. The differences from transmitter 10 are explained below.

The circulator 110 has a first port, a second port, and a third port. The first port of the circulator 110 is connected to the light source 104. The second port of the circulator 110 is connected to the collimator lens 106 via an optical fiber 105. The third port of the circulator 110 is connected to the optical receiving unit 111. An optical signal input to the first port is output from the second port. An optical signal input to the second port is output from the third port. An optical signal input to the third port is output from the first port.

For example, light waves output from the light source 104 are input to the first port of the circulator 110. The light waves input to the first port of the circulator 110 are output from the second port. For example, light waves reflected from the receiver 25 are input to the second port of the circulator 110. The light waves input to the second port of the circulator 110 are output from the third port.

The optical receiving unit 111 receives the light waves output from the third port of the circulator 110. The optical receiving unit 111 is, for example, a light receiver or a power meter. If the optical receiving unit 111 is a light receiver, the optical receiving unit 111 converts the received light waves into an electrical signal and obtains a current value or voltage value. If the optical receiving unit 111 is a power meter, the optical receiving unit 111 obtains the light intensity of the received light waves.

Receiver 25 comprises a condenser lens 201, a reflection medium 202, an antenna 203, and a reflector 208. The condenser lens 201, reflection medium 202, and reflector 208 of receiver 25 are receiver-side positioning devices, and may be provided externally rather than internally. Receiver 25 differs from receiver 20 in configuration in that it does not comprise a collimator lens 204 and in that it newly comprises a reflector 208. The rest of the configuration of receiver 25 is similar to that of receiver 20. The differences from receiver 20 are explained below.

The reflector 208 reflects the light waves reflected by the reflecting medium 202. The light waves reflected by the reflector 208 are reflected by the reflecting medium 202 and returned to the transmitter 15, as shown by the dotted line in Figure 10. The reflector 208 is one embodiment of a second reflecting section.

Next, the operation of the communication system 200 will be described. A user installing a transmitter 15 installs the transmitter 15 equipped with a transmitter positioning device at a candidate installation location. A user installing a receiver 25 installs the receiver 25 equipped with a receiver positioning device at a candidate installation location. The light source 104 of the transmitter 15 outputs a light wave. The light wave output by the light source 104 is input to the first port of the circulator 110. The light wave input to the first port of the circulator 110 is output from the second port of the circulator 110. The light wave output from the second port of the circulator 110 is input to the collimator lens 106 via the optical fiber 105. The collimator lens 106 converts the input light wave into a parallel light and outputs it to the reflection medium 107. The light wave output from the collimator lens 106 is reflected by the reflection medium 107.

The signal generation unit 101 generates a signal. The signal generation unit 101 outputs the generated signal to the transmission unit 102. The transmission unit 102 transmits the signal generated by the signal generation unit 101 via the antenna 103 as millimeter wave or terahertz wave radio waves. As a result, the radio waves output from the transmitter 15 and light waves are transmitted coaxially. The antenna 203 of the receiver 25 receives the radio waves. The light waves output from the transmitter 15 are reflected by the reflection medium 202 and directed toward the reflector 208. The light waves reflected by the reflection medium 202 are reflected by the reflector 208 and directed toward the reflection medium 202. The light waves reflected by the reflector 208 are reflected by the reflection medium 202 and transmitted to the transmitter 15.

The reflection medium 107 of the transmitter 15 reflects the light waves reflected by the receiver 25. The light waves reflected by the reflection medium 107 are input to the collimator lens 106. The light waves input to the collimator lens 106 are input to the second port of the circulator 110 via the optical fiber 105. The light waves input to the second port of the circulator 110 are output from the third port. The optical receiver 111 receives the light waves output from the third port of the circulator 110. The optical receiver 111 obtains either a current value, a voltage value, or an optical intensity based on the received light waves. Based on the current value, voltage value, or optical intensity obtained by the optical receiver 111, the user determines the positions of the antenna 103 of the transmitter 15 and the antenna 203 of the receiver 25 so that either the current value, voltage value, or optical intensity is maximized.

In the communication system 200 configured as described above, the light waves transmitted by the transmitter 15 are reflected and returned by the receiver 25, and are then received by the transmitter 15, thereby determining the positions of the transmitter 15 and the receiver 25 in a coordinated manner. By adjusting the positions of the transmitter 15 and the receiver 25 in this way, it is possible to achieve positioning that results in higher communication efficiency than in the first embodiment.

(Modification 1 of the second embodiment)
In the above-described embodiment, the transmitter 15 is configured to transmit millimeter or terahertz radio waves and light waves on a coaxial line in a manner similar to that of the transmitter 10. The transmitter 15 may be configured to transmit millimeter or terahertz radio waves and light waves on a coaxial line in a manner similar to that of any of the transmitters 10a, 10b, 10c, and 10d. In this configuration, the transmitter 15 has a configuration similar to that of any of the transmitters 10a, 10b, 10c, and 10d. For example, if the transmitter 15 transmits millimeter or terahertz radio waves and light waves on a coaxial line in a manner similar to that of the transmitter 10a, the transmitter 15 includes a reflection medium 107a instead of the reflection medium 107. For example, if the transmitter 15 transmits millimeter or terahertz radio waves and light waves on a coaxial line in a manner similar to that of the transmitter 10b, the transmitter 15 further includes a lens 108. For example, when transmitter 15 transmits millimeter or terahertz radio waves and light waves coaxially in the same manner as transmitter 10c, transmitter 15 further includes a parabolic mirror 109. For example, when transmitter 15 transmits millimeter or terahertz radio waves and light waves coaxially in the same manner as transmitter 10d, transmitter 15 does not include reflective medium 107, but further includes lens 108 and parabolic mirror 109, and collimator lens 106 is installed at the opening of parabolic mirror 109.

(Modification 2 of the second embodiment)
The transmitter 15 and the receiver 25 in the communication system 200 may have the configuration shown in Fig. 11. Fig. 11 is a diagram showing an example of the configuration of a communication system 300 in Modification 2 of the second embodiment. The communication system 300 includes a transmitter 15a and a receiver 25a.

Transmitter 15a transmits light waves of multiple wavelengths and millimeter or terahertz radio waves on a coaxial line using any of transmitters 10, 10a, 10b, 10c, and 10d in the first embodiment. Furthermore, transmitter 15a receives the light waves reflected by receiver 25a.

Transmitter 15a includes a signal generating unit 101, a transmitting unit 102, an antenna 103, an optical fiber 105, a collimator lens 106, a reflection medium 107, a circulator 110, an optical receiving unit 111, and a variable light source 112. The optical fiber 105, collimator lens 106, reflection medium 107, circulator 110, optical receiving unit 111, and variable light source 112 included in transmitter 15a are transmitting-side positioning devices, and may be provided externally rather than internally to transmitter 15a. Transmitter 15a differs in configuration from transmitter 15 in that it includes a variable light source 112 instead of light source 104. The remaining configuration of transmitter 15a is similar to that of transmitter 15. The differences from transmitter 15 are described below.

The variable light source 112 outputs light waves of a plurality of different wavelengths, for example, the variable light source 112 outputs light waves of two wavelengths λ ₁ and λ ₂ .

Receiver 25a includes a condenser lens 201, a reflection medium 202, an antenna 203, a collimator lens 204, a reflector 208, a multiplexer/demultiplexer 209, and an optical receiving unit 210. The condenser lens 201, reflection medium 202, reflector 208, multiplexer/demultiplexer 209, and optical receiving unit 210 included in receiver 25a are receiver-side positioning devices, and may be provided externally rather than internally. Receiver 25a differs in configuration from receiver 25 in that it newly includes multiplexer/demultiplexer 209 and optical receiving unit 210. The rest of the configuration of receiver 25a is similar to that of receiver 25. The differences from receiver 25 are explained below.

The multiplexer/demultiplexer 209 multiplexes/demultiplexes the input light waves. For example, the multiplexer/demultiplexer 209 demultiplexes the light waves of multiple wavelengths output from the collimator lens 204 into individual wavelengths. The multiplexer/demultiplexer 209 is, for example, a WDM (Wavelength Division Multiplexing) coupler or an AWG (Arrayed Waveguide Grating).

The optical receiving unit 210 receives the light waves separated by the multiplexer/demultiplexer 209. The optical receiving unit 210 is, for example, a photoreceiver or a power meter. If the optical receiving unit 210 is a photoreceiver, the optical receiving unit 210 converts the received light waves into electrical signals and obtains a current value or voltage value. If the optical receiving unit 210 is a power meter, the optical receiving unit 210 obtains the optical intensity of the received light waves.

Next, the operation of the communication system 300 will be described. A user installing the transmitter 15a installs the transmitter 15a equipped with a transmitter positioning device at a candidate installation location. A user installing the receiver 25a installs the receiver 25a equipped with a receiver positioning device at a candidate installation location. The variable light source 112 of the transmitter 15a outputs light waves of multiple different wavelengths λ ₁ and λ _2. The light waves of multiple different wavelengths λ ₁ and λ ₂ output by the variable light source 112 are input to a first port of the circulator 110. The light waves of multiple different wavelengths λ ₁ and λ ₂ input to the first port of the circulator 110 are output from a second port of the circulator 110. The light waves of multiple different wavelengths λ ₁ and λ ₂ output from the second port of the circulator 110 are input to the collimator lens 106 via the optical fiber 105. The collimator lens 106 converts the input light waves of different wavelengths λ ₁ and λ ₂ into parallel light and outputs them to the reflection medium 107. The light waves of different wavelengths λ ₁ and λ ₂ output from the collimator lens 106 are reflected by the reflection medium 107.

The signal generating unit 101 generates a signal. The signal generating unit 101 outputs the generated signal to the transmitting unit 102. The transmitting unit 102 transmits the signal generated by the signal generating unit 101 as a millimeter wave or terahertz wave radio wave via the antenna 103. As a result, the radio wave output from the transmitter 15a and light waves of multiple different wavelengths λ ₁ and λ ₂ are transmitted coaxially. The antenna 203 of the receiver 25a receives the radio wave. The light waves of multiple different wavelengths λ ₁ and λ ₂ output from the transmitter 15a are reflected by the reflecting medium 202 and input to the collimator lens 204. The light waves of multiple different wavelengths λ ₁ and λ ₂ input to the collimator lens 204 are input to the multiplexer/demultiplexer 209. The multiplexer/demultiplexer 209 demultiplexes the input light waves of multiple different wavelengths λ ₁ and λ ₂ into individual wavelengths. For example, the light wave of wavelength λ ₁ separated by the multiplexer/demultiplexer 209 is output to the optical receiving section 210 , and the light wave of wavelength λ ₂ is output to the reflector 208 .

The optical receiving unit 210 receives the lightwave of wavelength _λ1 output from the multiplexer/demultiplexer 209. The optical receiving unit 210 obtains either a current value, a voltage value, or an optical intensity based on the received lightwave of wavelength _λ1 . The reflector 208 reflects the lightwave of wavelength _λ2 output from the multiplexer/demultiplexer 209. In this manner, the reflector 208 reflects at least one lightwave of wavelength λ2 (in the example of FIG. 11 , the lightwave of wavelength _λ2 ) out of the lightwaves of one or more wavelengths reflected by the reflection medium 202 (in the example of FIG. 11 , the lightwaves of wavelengths _λ1 and λ2). The lightwave of wavelength _λ2 reflected by the reflector 208 is reflected by the _reflection medium 202 via the multiplexer/demultiplexer 209 and the collimator lens 204, and is transmitted to the transmitter 15 a.

The reflection medium 107 of the transmitter 15a reflects the light wave of wavelength _λ2 reflected by the receiver 25. The light wave of wavelength _λ2 reflected by the reflection medium 107 is input to the collimator lens 106. The light wave of wavelength _λ2 input to the collimator lens 106 is input to the second port of the circulator 110 via the optical fiber 105. The light wave of wavelength _λ2 input to the second port of the circulator 110 is output from the third port. The optical receiving unit 111 receives the light wave of wavelength _λ2 output from the third port of the circulator 110. The optical receiving unit 111 obtains any one of a current value, a voltage value, or light intensity based on the received light wave of wavelength _λ2 .

Based on either the current value, voltage value, or light intensity acquired by the optical receiving unit 111 and either the current value, voltage value, or light intensity acquired by the optical receiving unit 210, the user determines the positions of the antenna 103 of the transmitter 15a and the antenna 203 of the receiver 25a so that either the current value, voltage value, or light intensity is maximized. In this way, by installing an optical receiver or power meter on each of the transmitting and receiving sides and determining the positions of the antenna 103 of the transmitter 15a and the antenna 203 of the receiver 25a so that either the current, voltage, or light intensity is maximized on both sides, it becomes possible to more accurately and easily position the transmitting and receiving sides.

The configuration of the transmitter 15a and receiver 25a shown in Figure 11 is not limited to the configuration of the circulator 110 and the multiplexer/demultiplexer 209. For example, in the example shown in Figure 11, two wavelengths are used, so the same effect can be achieved by combining a 2x2 optical coupler and a WDM filter instead of the circulator 110 and the multiplexer/demultiplexer 209.

In the example shown in FIG. 11, transmitter 15a is configured to transmit millimeter-wave or terahertz radio waves and light waves on a coaxial line in a manner similar to that of transmitter 10. Transmitter 15a may also be configured to transmit millimeter-wave or terahertz radio waves and light waves on a coaxial line in a manner similar to that of any of transmitters 10a, 10b, 10c, and 10d. In this configuration, transmitter 15a has a configuration similar to that of any of transmitters 10a, 10b, 10c, and 10d. For example, if transmitter 15a transmits millimeter-wave or terahertz radio waves and light waves on a coaxial line in a manner similar to that of transmitter 10a, transmitter 15a includes reflection medium 107a instead of reflection medium 107. For example, if transmitter 15a transmits millimeter-wave or terahertz radio waves and light waves on a coaxial line in a manner similar to that of transmitter 10b, transmitter 15a further includes lens 108. For example, if transmitter 15a transmits millimeter or terahertz radio waves and light waves coaxially in the same manner as transmitter 10c, transmitter 15a further includes a parabolic mirror 109. For example, if transmitter 15a transmits millimeter or terahertz radio waves and light waves coaxially in the same manner as transmitter 10d, transmitter 15a does not include reflective medium 107, but further includes lens 108 and parabolic mirror 109, with collimator lens 106 installed at the opening of parabolic mirror 109.

(Modification 3 of the second embodiment)
The transmitter 15 and the receiver 25 in the communication system 200 may have the configuration shown in Fig. 12. Fig. 12 is a diagram showing an example configuration of a communication system 400 in Modification 3 of the second embodiment. The communication system 400 includes the transmitter 15 and a receiver 25b. The transmitter 15 included in the communication system 400 is the same as the transmitter 15 shown in Fig. 10.

Receiver 25b includes a condenser lens 201, a reflection medium 202, an antenna 203, a collimator lens 204, a reflector 208, an optical receiving unit 210, and a multiplexer/splitter 211. The condenser lens 201, reflection medium 202, collimator lens 204, a reflector 208, an optical receiving unit 210, and a multiplexer/splitter 211 included in receiver 25b are receiver-side positioning devices, and may be provided externally rather than internally. Receiver 25b differs from receiver 25a in that it includes a multiplexer/splitter 211 instead of a multiplexer/splitter 209. The rest of the configuration of receiver 25b is similar to that of receiver 25a. The differences from receiver 25a are explained below.

The splitter 211 splits the light waves output from the collimator lens 204 to the reflector 208 and the optical receiver 210.

In the example shown in FIG. 12, transmitter 15 is configured to transmit millimeter or terahertz radio waves and light waves on the same axis in a manner similar to that of transmitter 10. Transmitter 15 may also be configured to transmit millimeter or terahertz radio waves and light waves on the same axis in a manner similar to that of any of transmitters 10a, 10b, 10c, and 10d.

(Modification 4 of the second embodiment)
The transmitter 15 and the receiver 25 in the communication system 200 may have the configuration shown in Fig. 13. Fig. 13 is a diagram showing an example of the configuration of a communication system 500 according to a fourth modification of the second embodiment. The communication system 500 includes a transmitter 15b and a receiver 25c.

Transmitter 15b includes a signal generating unit 101, a transmitting unit 102, an antenna 103, an optical fiber 105, a collimator lens 106, a reflection medium 107, a circulator 110, an optical receiving unit 111, and a variable light source 112b. The optical fiber 105, collimator lens 106, reflection medium 107, circulator 110, optical receiving unit 111, and variable light source 112b included in transmitter 15b are transmitting-side positioning devices, and may be provided externally rather than internally. Transmitter 15b differs in configuration from transmitter 15a in that it includes a variable light source 112b instead of variable light source 112. The remaining configuration of transmitter 15b is similar to that of transmitter 15a. The differences from transmitter 15a are described below.

The variable light source 112b outputs light waves of a plurality of different wavelengths. For example, the variable light source 112b outputs light waves of three wavelengths λ ₁ , λ ₂ , and λ _3. The variable light source 112b transmits a modulated signal using the light wave of wavelength λ ₃ as a carrier.

Receiver 25b includes a condenser lens 201, a reflection medium 202, an antenna 203, a collimator lens 204, a reflector 208, a multiplexer/demultiplexer 209, an optical receiving unit 210, and an optical receiving unit 212. The condenser lens 201, the reflection medium 202, the reflector 208, the multiplexer/demultiplexer 209, the optical receiving unit 210, and the optical receiving unit 212 included in receiver 25b are receiver-side positioning devices, and may be provided externally rather than internally in receiver 25b. Receiver 25b differs in configuration from receiver 25a in that it newly includes an optical receiving unit 212. The rest of the configuration of receiver 25b is similar to that of receiver 25a. The differences from receiver 25a are explained below.

The optical receiving section 212 receives the light wave with wavelength λ _3. This makes it possible to expand the transmission band in the same space by combining radio transmission and optical space transmission.

The above describes in detail an embodiment of the present invention with reference to the drawings, but the specific configuration is not limited to this embodiment and includes designs that do not deviate from the gist of the present invention.

10, 10a, 10b, 10c, 10d, 15, 15a, 15b...Transmitter, 20, 20a, 20b, 20c, 25, 25a, 25b, 25c...Receiver, 101...Signal generation unit, 102...Transmitter, 103, 203...Antenna, 104...Light source, 105...Optical fiber, 106, 204...Collimator lens, 107, 202...Reflecting medium, 108...Lens, 109...Parabolic mirror, 110...Circulator, 111...Optical receiving unit, 112, 112b...Tunable light source, 201...Condenser lens, 205...Photodetector, 206...Optical receiving element, 207...RF receiving element, 208...Reflector, 209...Multiplexer/Demultiplexer 210, 212...Optical receiving unit, 211...Divider/combiner, 100, 200, 300, 400, 500...Communication system

Claims (6)

a transmitter that transmits millimeter wave or terahertz wave radio waves via an antenna;
a light source that outputs light waves of one or more wavelengths;
a reflecting section for coaxially transmitting the radio wave and the light wave of one or more wavelengths;
Equipped with
the reflecting unit is a reflecting medium that is installed coaxially with the antenna and reflects the light waves of the one or more wavelengths output from the light source, thereby transmitting the radio waves and the light waves of the one or more wavelengths coaxially;
Alternatively, a combination of a reflection medium that is installed on the same axis as the antenna and that reflects the light waves of the one or more wavelengths output from the light source to transmit the radio waves and the light waves of the one or more wavelengths on the same axis, and a first mirror that changes the paths of the radio waves and the light waves of the one or more wavelengths;
or a second mirror having an opening for outputting the light waves of one or more wavelengths output from the light source and for changing the direction of the radio waves.
Transmitter . a focusing lens for focusing light waves of one or more wavelengths transmitted from a transmitter;
an antenna for receiving at least the radio waves transmitted coaxially with the light waves of the one or more wavelengths transmitted from the transmitter;
a receiving unit that receives light waves of the one or more wavelengths at either a front stage or a rear stage of the antenna;
a reflecting member that reflects the light waves of the one or more wavelengths among the light waves of the one or more wavelengths and the radio waves transmitted from the transmitter on the same axis at a stage preceding the antenna,
the receiving unit receives the light waves of the one or more wavelengths reflected by the reflecting member.
Receiver . a focusing lens for focusing light waves of one or more wavelengths transmitted from a transmitter;
an antenna for receiving at least the radio waves transmitted coaxially with the light waves of the one or more wavelengths transmitted from the transmitter;
a receiving unit that receives light waves of the one or more wavelengths at either a front stage or a rear stage of the antenna;
Equipped with
the receiving unit receives light waves of the one or more wavelengths among the light waves of the one or more wavelengths and the radio waves propagated within the antenna,
Receiver . A communication system comprising a transmitter and a receiver,
The transmitter
a transmitter that transmits millimeter wave or terahertz wave radio waves via an antenna;
a light source that outputs light waves of one or more wavelengths;
a reflecting section that is installed coaxially with the antenna and reflects the light waves of the one or more wavelengths output from the light source, thereby transmitting the radio waves and the light waves of the one or more wavelengths coaxially;
an acquisition unit that receives the light wave reflected from the receiver via the reflection unit and acquires one of a current value, a voltage value, and a light intensity based on the received light wave;
Equipped with
The receiver includes:
a first reflecting section that reflects light waves of the one or more wavelengths among the light waves of the one or more wavelengths and the radio waves transmitted coaxially from the transmitter;
a second reflecting section that reflects light waves of at least one wavelength among the light waves of the one or more wavelengths reflected by the first reflecting section;
Equipped with
The first reflecting section reflects the light wave of one wavelength reflected by the second reflecting section to the transmitter. The receiver includes:
an acquisition unit that acquires any one of a current value, a voltage value, and a light intensity based on the light waves of the one or more wavelengths;
a distribution unit that branches or separates the light waves of the one or more wavelengths reflected by the first reflection unit and outputs the branched light waves to at least the second reflection unit and the acquisition unit;
Further provided with
5. The communication system according to claim 4 . A method for acquiring position determination information of a transmitter and a receiver in a communication system including the transmitter and the receiver, comprising:
The transmitter:
Millimeter wave or terahertz wave radio waves are transmitted via an antenna,
outputting light waves of one or more wavelengths;
By reflecting the light waves of the one or more wavelengths, the radio waves and the light waves of the one or more wavelengths are transmitted on the same axis;
receiving the reflected light wave from the receiver, and acquiring any one of a current value, a voltage value, and a light intensity based on the received light wave;
The receiver,
reflecting light waves of the one or more wavelengths among the light waves of the one or more wavelengths and the radio waves transmitted from the transmitter on the same axis;
reflecting at least one light wave of the one or more wavelengths reflected, and reflecting the light wave of the one wavelength to the transmitter;
How to obtain positioning information.