Sensing system, transmission device, program, and sensing method

Abstract

A transmission device comprises: an optical signal generation unit that generates an optical signal; an amplitude-phase designation unit that splits the optical signal generated by the optical signal generation unit into a plurality of optical signals, and specifies the amplitude and the phase of each of the plurality of optical signals resulting from the splitting; a plurality of signal conversion units that convert the plurality of optical signals, for which the amplitude and the phase have been specified by the amplitude-phase designation unit, into a plurality of electrical signals; and a plurality of transmission antennas that wirelessly transmit the plurality of electrical signals into which the plurality of signal conversion units have made the conversion.

Description

Sensing system, transmitting device, program, and sensing method

[0001] The present invention relates to a sensing system, a transmitting device, a program, and a sensing method.

[0002] Conventionally, a sensing system is known in which a transmitting device transmits a wireless signal to an object to be sensed, a receiving device receives the wireless signal that has passed through the object, and the system obtains information about the object by analyzing the received signal (Non-Patent Document 1).

[0003] The resolution of conventional sensing systems is proportional to the aperture area of ​​the transmitting antenna and the frequency used. Therefore, by arranging multiple transmitting antennas to virtually expand the antenna area and by using radio waves in the higher frequency band, high-resolution sensing systems can be achieved.

[0004] In conventional sensing systems, a transmitting device adds weights to multiple wireless signals and transmits them from its transmitting antenna. The receiving device then converts the weight information added to the wireless signals into channel information to perform sensing of the object to be sensed.

[0005] Ali Mostajeran, Member, SM Hossein Naghavi, Mohammad Emadi, Mohammed Aseeri, and Ehsan Afshari, “A High-Resolution 220-GHz Ultra-Wideband Fully Integrated ISAR Imaging System”, IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES, VOL. 67, NO. 1, JANUARY 2019

[0006] In conventional sensing systems, the transmitting device has an electrical circuit that supplies power to numerous transmitting antennas that utilize high frequencies. As a result, power loss is significant due to the magnitude of attenuation in the high-frequency circuit and the size of the high-frequency circuit. Therefore, when sensing an object using a wireless signal transmitted from the transmitting device and received by the receiving device, the power consumption of the transmitting device becomes large.

[0007] The present invention aims to provide a technology that reduces power loss and lowers power consumption in the transmitting device when sensing an object using a wireless signal transmitted from a transmitting device and received by a receiving device, by using an optical signal.

[0008] One aspect of the present invention is a sensing system comprising a transmitting device and a receiving device, wherein the transmitting device comprises an optical signal generating unit that generates an optical signal, an amplitude phase specifying unit that branches the optical signal generated by the optical signal generating unit into a plurality of optical signals and specifies the amplitude phase of each of the branched plurality of optical signals, a plurality of signal conversion units that convert the plurality of optical signals whose amplitude phases have been specified by the amplitude phase specifying unit into a plurality of electrical signals, and a plurality of transmitting antennas that wirelessly transmit the plurality of electrical signals converted by the plurality of signal conversion units, and the receiving device comprises a plurality of receiving antennas that wirelessly receive the plurality of electrical signals transmitted from the plurality of transmitting antennas, and a sensing information acquisition unit that acquires information about an object to be sensed based on the plurality of electrical signals received by the plurality of receiving antennas.

[0009] Another aspect of the present invention is a transmitting device comprising: an optical signal generation unit that generates an optical signal; an amplitude phase specification unit that branches the optical signal generated by the optical signal generation unit into a plurality of optical signals and specifies the amplitude phase of each of the branched plurality of optical signals; a plurality of signal conversion units that convert the plurality of optical signals whose amplitude phases have been specified by the amplitude phase specification unit into a plurality of electrical signals; and a plurality of transmitting antennas that wirelessly transmit the plurality of electrical signals converted by the plurality of signal conversion units.

[0010] Furthermore, yet another aspect of the present invention is a program that causes the computer of a transmitting device to execute an optical signal generation process for generating an optical signal; an amplitude phase specification process for branching the optical signal generated in the optical signal generation process into a plurality of optical signals and specifying the amplitude phase of each of the branched plurality of optical signals; a signal conversion process for converting the plurality of optical signals whose amplitude phases have been specified in the amplitude phase specification process into a plurality of electrical signals; and a wireless transmission process for wirelessly transmitting the plurality of electrical signals converted in the signal conversion process from a plurality of transmitting antennas.

[0011] Furthermore, yet another aspect of the present invention is a sensing method using a transmitting device and a receiving device, comprising: an optical signal generation process in which the transmitting device generates an optical signal; an amplitude phase specification process in which the transmitting device branches the optical signal generated in the optical signal generation process into a plurality of optical signals and specifies the amplitude phase of each of the branched plurality of optical signals; a signal conversion process in which the transmitting device converts the plurality of optical signals whose amplitude phases have been specified in the amplitude phase specification process into a plurality of electrical signals; a wireless transmission process in which the transmitting device wirelessly transmits the plurality of electrical signals converted in the signal conversion process from a plurality of transmitting antennas; a wireless reception process in which the receiving device wirelessly receives the plurality of electrical signals transmitted from the plurality of transmitting antennas with a plurality of receiving antennas; and a sensing information acquisition process in which the receiving device acquires information about an object to be sensed based on the plurality of electrical signals received in the wireless reception process.

[0012] According to the present invention, when sensing an object using a wireless signal transmitted from a transmitting device and received by a receiving device, power loss can be reduced and power consumption in the transmitting device can be decreased by using an optical signal.

[0013] This is a schematic block diagram showing the configuration of a sensing system according to the first embodiment of the present invention. This is a diagram showing an example of an optical signal output from the weighting unit to the photomixer. This is a diagram showing an example of an optical signal output from the weighting unit to the photomixer. This is a diagram showing an example of an optical signal output from the weighting unit to the photomixer. This is a diagram showing an example of an optical signal output from the weighting unit to the photomixer. This is a flowchart showing the first process performed by the sensing system according to the first embodiment of the present invention. This is a flowchart showing the second process performed by the sensing system according to the first embodiment of the present invention. This is a sequence diagram showing the process performed by the sensing system according to the first embodiment of the present invention. This is a schematic block diagram showing the configuration of a sensing system according to the second embodiment of the present invention. This is a schematic block diagram showing the configuration of a sensing system according to the third embodiment of the present invention. This is a schematic block diagram showing the configuration of a sensing system according to the fourth embodiment of the present invention.

[0014] Hereinafter, the first to fourth embodiments of the present invention will be described with reference to the drawings. First, the first embodiment of the present invention will be described.

[0015] [First Embodiment] First, a first embodiment of the present invention will be described. Figure 1 is a schematic block diagram showing the configuration of a sensing system 1000a according to the first embodiment of the present invention. The sensing system 1000a includes a transmitting device 100a and a receiving device 200a. In the first embodiment, a sensing object 300a is placed between the transmitting device 100a and the receiving device 200a. At least a portion of the wireless signal transmitted from the transmitting device 100a passes through the sensing object 300a and is received by the receiving device 200a.

[0016] The transmitting device 100a includes an optical signal generation unit 10a, a weighting unit 11a (also referred to as an amplitude phase specification unit), photomixers 12a-1, 12a-2, ..., 12a-M (where M is an integer of 2 or more), and transmitting antennas 13a-1, 13a-2, ..., 13a-M.

[0017] The optical signal generation unit 10a generates an optical signal to be transmitted from the transmitting device 100a to the receiving device 200a and outputs it to the weighting unit 11a. The weighting unit 11a splits the single optical signal generated by the optical signal generation unit 10a into M optical signals. The weighting unit 11a then assigns weights to the M branched optical signals by controlling them to have the same or different amplitude phases, and outputs the M weighted optical signals to the photomixers 12a-1, 12a-2, ..., 12a-M. The weights can be assigned by any means, such as differences in path length, phase shifters, matrix circuits, or reactions to temperature.

[0018] Figures 2A and 2B show an example of an optical signal output from the weighting unit 11a to the photomixer 12a-1. As shown in Figure 2A, the weighting unit 11a outputs a predetermined carrier wave A1 and an optical signal A2 that exists at a frequency f1 away from the carrier wave A1 to the photomixer 12a-1. The photomixer 12a-1 converts the optical signal into an electrical signal by intensity modulation or the like, generating an electrical signal at a frequency corresponding to the frequency difference between optical signals A1 and A2, and with phase conditions corresponding to the phase difference. For example, Figure 2B shows an example where the electrical signal generated from optical signals A1 and A2 shown in Figure 2A is observed as an electrical signal at the corresponding frequency f1. Here, the phase in IQ refers to the case where the phase on the I-axis (in Figure 2B, the phase rotation angle is 0 degrees) is given in a complex plane consisting of the I-axis and Q-axis.

[0019] Note that the signals shown in Figures 2A and 2B are exp(i2πft) + {(s １ (t)exp(i2π(f+f １ It is expressed as {(s １ (t)exp(i2π(f+f １ The term )t))} refers to signal A2 shown in Figures 2A and 2B.

[0020] FIGS. 3A and 3B are diagrams showing an example of an optical signal output from the weight application unit 11a to the photomixer 12a-M. As shown in FIG. 3A, a predetermined carrier wave A1 and an optical signal A2 existing at a frequency separated by a predetermined frequency f1 from the carrier wave A1 are output from the weight application unit 11a to the photomixer 12a-M. At this time, it has a phase component corresponding to the phase difference between the carrier wave A1 and the optical signal A2. The weight application unit 11a applies a phase to the carrier wave A1 or the optical signal A2, or both, such that the phase difference between the carrier wave A1 and the optical signal A2 is θ Ｍ becomes. For example, in FIG. 3B, by applying a phase to the carrier wave A1 or the optical signal A2, or both, and controlling so that the phase difference is θ Ｍ becomes, a case where a predetermined phase rotation (in FIG. 3B, the angle of the phase rotation is θ Ｍ degrees) is given in the complex plane composed of the I-axis and the Q-axis is shown.

[0021] Incidentally, in FIG. 3A, assuming that a phase θ Ｍ is given to A2, the signals shown in FIGS. 3A and 3B are exp(i2πft) + {((s １ (t) exp(i2π(f + f １ )t + θ Ｍ ))}. The term exp(i2πt) indicates the signal A1 shown in FIGS. 3A and 3B. The term {((s １ (t) exp(i2π(f + f １ )t + θ Ｍ ))} indicates the signal A2 shown in FIGS. 3A and 3B, and a term related to θ Ｍ is added.

[0022] Returning to the explanation of Figure 1, the photomixers 12a-m (where m is an integer between 1 and M) convert the m-th optical signal output from the weighting unit 11a into an electrical signal and output it to the transmitting antenna 13a-m. For example, photomixer 12a-1 converts the first optical signal output from the weighting unit 11a, the optical signal shown in Figures 2A and 2B, into an electrical signal and outputs it to the transmitting antenna 13a-1. Similarly, photomixer 12a-M converts the M-th optical signal output from the weighting unit 11a, the optical signal shown in Figures 3A and 3B, into an electrical signal and outputs it to the transmitting antenna 13a-M. Note that photomixers 12a-1, 12a-2, ..., 12a-M are composed of photoelectric conversion devices such as photodiodes.

[0023] The transmitting antenna 13a-m transmits the electrical signal output from the photomixer 12a-m as a wireless signal to the receiving device 200a. For example, the transmitting antenna 13a-1 transmits the electrical signal output from the photomixer 12a-1 as a wireless signal to the receiving device 200a. Also, the transmitting antenna 13a-M transmits the electrical signal output from the photomixer 12a-M as a wireless signal to the receiving device 200a.

[0024] The transmitting device 100a also includes a control unit and a memory unit, but these are omitted from the illustration in Figure 1. The control unit of the transmitting device 100a is composed of a CPU (Central Processing Unit) and controls the various parts of the transmitting device 100a. The memory unit of the transmitting device 100a is composed of RAM (Random Access Memory) and ROM (Read Only Memory) and stores programs for driving the transmitting device 100a and data to be transmitted from the transmitting device 100a to the receiving device 200a.

[0025] The receiving device 200a comprises signal receiving units 20a-1 to 20a-L (where L is an integer of 2 or more) and a sensing information acquisition unit 21a. The signal receiving units 20a-1 to 20a-L are equipped with L receiving antennas. The signal receiving units 20a-1 to 20a-L receive the radio signals transmitted from the transmitting antennas 13a-1 to 13a-M of the transmitting device 100a using the L receiving antennas and output them as electrical signals to the sensing information acquisition unit 21a. Note that integers M and L may be different integers, but here we will describe the case where integers M and L are the same integer.

[0026] The sensing information acquisition unit 21a acquires sensing information of the sensing target unit 300a located between the transmitting device 100a and the receiving device 200a, based on L electrical signals output from the signal receiving units 20a-1 to 20a-L.

[0027] The receiving device 200a also includes a control unit and a storage unit, but these are omitted from the illustration in Figure 1. The control unit of the receiving device 200a is composed of a CPU and the like, and controls the various parts of the receiving device 200a. The storage unit of the receiving device 200a is composed of RAM, ROM, and the like, and stores programs for driving the receiving device 200a, as well as data that the receiving device 200a receives from the transmitting device 100a.

[0028] Figure 4 is a flowchart showing the first process performed by the sensing system 1000a according to the first embodiment of the present invention. First, the multiple transmitting antennas 13a-1 to 13a-M of the transmitting device 100a transmit a wireless signal to the receiving device 200a when there is no object to be sensed 300a present (step S101).

[0029] Next, the multiple signal receiving units 20a-1 to 20a-L of the receiving device 200a perform calibration based on the radio signal transmitted in step S102 (step S102). This calibration process is performed by the multiple signal receiving units 20a-1 to 20a-L or the sensing information acquisition unit 21a to eliminate any difference between the initial state expected by the multiple signal receiving units 20a-1 to 20a-L and the reception state when the radio signal transmitted in step S101 is received by the multiple signal receiving units 20a-1 to 20a-L. Note that instead of the receiving device 200a performing the process to eliminate the difference, the value of the difference may be fed back from the receiving device 200a to the transmitting device 100a, and the transmitting device 100a may adjust so that no difference occurs in the receiving device 200a.

[0030] Next, once the initial setup of the sensing system 1000a is completed in steps S101 and S102, the transmitting device 100a and the receiving device 200a start the sensing process of the object to be sensed 300a (step S103).

[0031] Next, the sensing information acquisition unit 21a receives the wireless signals transmitted by the transmitting antennas 13a-1 to 13a-M of the transmitting device 100a and performs sensing processing of the sensing target object 300a (step S104).

[0032] Figure 5 is a flowchart showing the second process performed in the sensing system 1000a according to the first embodiment of the present invention. First, the multiple transmitting antennas 13a-1 to 13a-M of the transmitting device 100a transmit a radio signal to the receiving device 200a that has been weighted based on the phase as described in Figures 2B and 3B (step S201).

[0033] Next, the sensing information acquisition unit 21a of the receiving device 200a converts the weights assigned to the wireless signal into channel information relating to the multiple transmitting antennas 13a-1 to 13a-M of the transmitting device 100a (step S202).

[0034] Next, the sensing information acquisition unit 21a of the receiving device 200a performs sensing of the sensing target 300a based on the channel information converted in step S202 (step S203).

[0035] FIG. 6 is a sequence diagram showing the processes performed in the sensing system 1000a according to the first embodiment of the present invention. First, the optical signal generation unit 10a of the transmitting device 100a generates an optical signal for transmission from the transmitting device 100a to the receiving device 200a (step S301).

[0036] Next, the weighting unit 11a of the transmitting device 100a branches the optical signal generated in step S301 into a plurality of optical signals (here, M optical signals), and designates the amplitude and phase of each of the branched plurality of optical signals based on the phases described in FIGS. 2B and 3B (step S302).

[0037] Next, the photomixers 12a-1, 12a-2,..., 12a-M of the transmitting device 100a convert the plurality of optical signals whose amplitude and phase are designated in step S302 into a plurality of electrical signals (here, M electrical signals) (step S303).

[0038] Next, the transmitting antennas 13a-1, 13a-2,..., 13a-M of the transmitting device 100a wirelessly transmit the plurality of electrical signals converted in step S303 as wireless signals to the receiving device 200a (step S304). At least a part of the electrical signals transmitted from the transmitting antennas 13a-1, 13a-2,..., 13a-M of the transmitting device 100a passes through the sensing target 300a existing between the transmitting device 100a and the receiving device 200a and reaches the receiving device 200a.

[0039] Next, the receiving antennas included in the signal receiving units 20a-1 to 20a-L of the receiving device 200a wirelessly receive the plurality of wireless signals transmitted in step S204 and generate a plurality of electrical signals (step S305).

[0040] Next, the sensing information acquisition unit 21a of the receiving device 200a acquires information regarding the sensing target object 300a based on the plurality of electrical signals generated in step S305 (step S306). For example, the sensing information acquisition unit 21a specifies whether the electrical signal output from the signal receiving unit 20a-l (l is an integer of 1 or more and L or less) is based on the wireless signal transmitted from any of the transmission antennas 13a-1 to 13a-M, based on the phase given to the wireless signal. Then, the sensing information acquisition unit 21a acquires sensing information by specifying the state of the sensing target object 300a existing between the transmission antennas 13a-1 to 13a-M and the L receiving antennas included in the signal receiving units 20a-1 to 20a-L, based on the reception intensity at the L receiving antennas included in the signal receiving units 20a-1 to 20a-L.

[0041] In the above-described first embodiment, the photomixers 12a-1, 12a-2,..., 12a-M are used to generate the wireless signal transmitted from the transmitting device 100a to the receiving device 200a. And the weight is given to the signal transmitted from the transmitting device 100a to the receiving device 200a by the weight applying unit 11a which is an optical circuit, before the optical signal is converted into an electrical signal. Therefore, due to the low power consumption property of the optical circuit, the power consumption at the weight applying unit 11a can be reduced. Thus, when sensing the target object 300a using the wireless signal transmitted from the transmitting device 100a and received by the receiving device 200a, the power loss can be reduced by using the optical signal, and the power consumption at the transmitting device 100a can be decreased.

[0042] [Second Embodiment] Next, a second embodiment of the present invention will be described. FIG. 7 is a schematic block diagram showing the configuration of a sensing system 1000b according to the second embodiment of the present invention. The sensing system 1000b includes a transmitting device 100b and a receiving device 200b. In the second embodiment, a sensing target object 300b is arranged between the transmitting device 100b and the receiving device 200b. At least a part of the wireless signal transmitted from the transmitting device 100b passes through the sensing target object 300b and is received by the receiving device 200b.

[0043] The transmitting device 100b includes an optical signal generation unit 10b, a weighting unit 11b, photomixers 12b-1, 12b-2, ..., 12b-M (where M is an integer of 2 or more), and transmitting antennas 13b-1, 13b-2, ..., 13b-M. The receiving device 200b includes signal receiving units 20b-1 to 20b-L (where L is an integer of 2 or more) and a sensing information acquisition unit 21b.

[0044] Note that the configuration and processing of the optical signal generation unit 10b, weighting unit 11b, photomixers 12b-1, 12b-2, ..., 12b-M, transmitting antennas 13b-1, 13b-2, ..., 13b-M, and the signal receiving units 20b-1 to 20b-L and sensing information acquisition unit 21b of the receiving device 200b according to the second embodiment (Figure 7) are the same as the configuration and processing of the optical signal generation unit 10a, weighting unit 11a, photomixers 12a-1, 12a-2, ..., 12a-M, transmitting antennas 13a-1, 13a-2, ..., 13a-M, and the signal receiving units 20a-1 to 20a-L and sensing information acquisition unit 21a of the receiving device 200a according to the first embodiment (Figure 1), so their explanation will be omitted.

[0045] In the sensing system 1000b according to the second embodiment, the transmitting device 100b includes a curved member 14b. The transmitting antennas 13b-1, 13b-2, ..., 13b-M are arranged on the curved member 14b.

[0046] According to the sensing system 1000b of the second embodiment, similar to the sensing system 1000a of the first embodiment, when sensing an object 300b using a wireless signal transmitted from the transmitting device 100b and received by the receiving device 200b, power loss can be reduced by using an optical signal, thereby reducing the power consumption of the transmitting device 100b.

[0047] Furthermore, compared to the first embodiment, the sensing system 1000b according to the second embodiment allows at least a portion of the radio signals transmitted from the transmitting antennas 13b-1, 13b-2, ..., 13b-M arranged on the curved member 14b to pass through the sensing target object 300b more frequently, thus enabling more detailed sensing of the sensing target object 300b.

[0048] In the first embodiment (Figure 1), the case in which the transmitting antennas 13a-1 to 13a-M of the transmitting device 100a and the receiving antennas of the signal receiving units 20a-1 to 20a-L of the receiving device 200a are arranged opposite each other with the sensing object 300a in between is described. In the second embodiment (Figure 7), the case in which the transmitting antennas 13b-1 to 13b-M of the transmitting device 100b are arranged on the curved member 14b is described. However, the invention is not limited to these embodiments, and multiple transmitting antennas can be arranged at any position. Similarly, the receiving antennas can also be arranged at any position.

[0049] [Third Embodiment] Next, a third embodiment of the present invention will be described. Figure 8 is a schematic block diagram showing the configuration of a sensing system 1000c according to the third embodiment of the present invention. The sensing system 1000c includes a transmitting device 100c and a receiving device 200c. In the third embodiment, a sensing object 300c is placed between the transmitting device 100c and the receiving device 200c. At least a portion of the wireless signal transmitted from the transmitting device 100c passes through the sensing object 300c and is received by the receiving device 200c.

[0050] The transmitting device 100c includes an optical signal generation unit 10c, a weighting unit 11c, photomixers 12c-1-1, 12c-1-2, ..., 12c-1-M (where M is an integer of 2 or more), ..., 12c-N-1 (where N is an integer of 2 or more), 12c-N-2, ..., 12c-N-M, and transmitting antennas 13c-1-1, 13c-1-2, ..., 13c-1-M, ..., 13c-N-1, 13c-N-2, ..., 13c-N-M. The receiving device 200c includes signal receiving units 20c-1 to 20c-L (where L is an integer of 2 or more) and a sensing information acquisition unit 21c.

[0051] Furthermore, the third embodiment (Figure 8) includes the optical signal generation unit 10c, weighting unit 11c, photomixers 12c-1-1, 12c-1-2, ..., 12c-1-M, ..., 12c-N-1, 12c-N-2, ..., 12c-N-M, transmitting antennas 13c-1-1, 13c-1-2, ..., 13c-1-M, ..., 13c-N-1, 13c-N-2, ..., 13c-N-M, and the signal receiving unit 20c of the receiving device 200c. The configuration and processing of -1 to 20c-L and the sensing information acquisition unit 21c are the same as those of the optical signal generation unit 10a, weighting unit 11a, photo mixers 12a-1, 12a-2, ..., 12a-M, transmitting antennas 13a-1, 13a-2, ..., 13a-M, and the signal receiving units 20a-1 to 20a-L and sensing information acquisition unit 21a of the receiving device 200a according to the first embodiment (Figure 1), so their explanation will be omitted.

[0052] In the sensing system 1000c according to the third embodiment, the transmitting antennas 13c-1-1, 13c-1-2, ..., 13c-1-M, ..., 13c-N-1, 13c-N-2, ..., 13c-N-M of the transmitting device 100c are arranged in an M x N matrix.

[0053] According to the third embodiment of the sensing system 1000c, similar to the first embodiment of the sensing system 1000a, when sensing an object 300c using a wireless signal transmitted from the transmitting device 100c and received by the receiving device 200c, power loss can be reduced by using an optical signal, thereby reducing the power consumption of the transmitting device 100c.

[0054] Furthermore, compared to the first embodiment, in the sensing system 1000b according to the second embodiment, the transmitting antennas 13c-1-1, 13c-1-2, ..., 13c-1-M, ..., 13c-N-1, 13c-N-2, ..., 13c-N-M of the transmitting device 100c are arranged in an M x N matrix, thereby increasing the area of ​​the virtual transmitting antennas and improving the resolution of the sensing processing performed by the sensing information acquisition unit 21c of the receiving device 200c.

[0055] In the third embodiment, the case in which the transmitting antennas 13c-1-1, 13c-1-2, ..., 13c-1-M, ..., 13c-N-1, 13c-N-2, ..., 13c-N-M of the transmitting device 100c are arranged in a matrix of M rows x N columns was described, but the embodiment is not limited to this. For example, the receiving antennas of the receiving device 200c may also be arranged in a matrix.

[0056] [Fourth Embodiment] Next, a fourth embodiment of the present invention will be described. Figure 9 is a schematic block diagram showing the configuration of a sensing system 1000d according to the fourth embodiment of the present invention. The sensing system 1000d includes a transmitting device 100d and a receiving device 200d.

[0057] The transmitting device 100d includes an optical signal generation unit 10d, a weighting unit 11d, photomixers 12d-1, 12d-2, ..., 12d-M (where M is an integer of 2 or more), and transmitting antennas 13d-1, 13d-2, ..., 13d-M. The receiving device 200d includes signal receiving units 20d-1 to 20d-L (where L is an integer of 2 or more) and a sensing information acquisition unit 21d.

[0058] The configuration and processing of the optical signal generation unit 10d, weighting unit 11d, photomixers 12d-1, 12d-2, ..., 12d-M, transmitting antennas 13d-1, 13d-2, ..., 13d-M, and the signal receiving units 20d-1 to 20d-L and sensing information acquisition unit 21d of the receiving device 200d are the same as those of the optical signal generation unit 10a, weighting unit 11a, photomixers 12a-1, 12a-2, ..., 12a-M, transmitting antennas 13a-1, 13a-2, ..., 13a-M, and the signal receiving units 20a-1 to 20a-L and sensing information acquisition unit 21a of the receiving device 200a in the first embodiment (Figure 1), so their explanation will be omitted.

[0059] In the sensing system 1000d according to the fourth embodiment, the transmitting device 100d and the receiving device 200d are arranged side by side, rather than opposite each other. At least a portion of the radio signal transmitted from the transmitting device 100d is reflected off the sensing object 300d and received by the receiving device 200d.

[0060] According to the sensing system 1000d of the fourth embodiment, similar to the sensing system 1000a of the first embodiment, when sensing an object 300d using a wireless signal transmitted from a transmitting device 100d and received by a receiving device 200d, power loss can be reduced and the power consumption of the transmitting device 100d can be reduced by using an optical signal.

[0061] Furthermore, compared to the first embodiment, the sensing system 1000d according to the fourth embodiment allows sensing of the sensing object 300d even if there is no space to arrange the transmitting device 100d and the receiving device 200d opposite each other with the sensing object 300d in between. As long as there is space to arrange the transmitting device 100d and the receiving device 200d side by side, sensing of the sensing object 300d can be performed.

[0062] In the first to fourth embodiments, by newly adding an amplifier between the photomixer and the transmitting antenna, the transmission power can be increased and the accuracy of sensing can be improved.

[0063] In the first to fourth embodiments, the weight assignment unit efficiently transmits wireless signals from multiple transmitting antennas by using weights defined by an orthogonal matrix as transmission weights for the transmitting antennas. For example, when using M transmitting antennas, an M x M orthonormal basis is defined as the weights, and M types of weight vectors having M elements are used. By assigning weights corresponding to different weight vectors for each time slot in M ​​or multiples of M time slots, the received signals obtained by L signal receiving units are received in M ​​or multiples of M time slots, resulting in an L x M received signal matrix configuration. Using the inverse of the M x M matrix of the orthonormal basis, channel information corresponding to individual transmitting antennas can be obtained as sensing information. Furthermore, even without an orthonormal basis, channel information corresponding to individual transmitting antennas can be obtained from the inverse of a transmission weight matrix generated with any number of weight vectors. By transmitting wireless signals using weights in this way, wireless signals can be transmitted from all transmitting antennas at all times, compared to transmitting from each individual transmitting antenna. This allows for efficient use of power and is expected to improve sensing accuracy. Furthermore, by applying weighting to the optical signal, power loss due to the circuit, which can occur when applying weighting to an electrical signal, can be prevented.

[0064] Furthermore, we have demonstrated in experiments with actual equipment a method in which weights are generated in the optical domain using the weighting units 11a (shown in Figure 1), 11b (shown in Figure 7), 11c (shown in Figure 8), and 11d (shown in Figure 9), and photoelectric conversion is performed using the photomixers 12a (shown in Figure 1), 12b (shown in Figure 7), 12c (shown in Figure 8), and 12d (shown in Figure 9), and the weights are reflected in the output RF signal.

[0065] Furthermore, the sensing information acquisition unit in the first to fourth embodiments may use a machine learning algorithm to acquire information on the object to be sensed. The machine learning algorithm may also be pre-trained on the object to be sensed. In training the sensing of the object to be sensed, training data including information on the transmission weight used in the transmitting device may be generated by actual measurement or simulation, and the accuracy of the sensing of the sensing information acquisition unit may be improved using this training data.

[0066] Furthermore, at least some of the functions of the transmitting and receiving devices in the first to fourth embodiments described above may be implemented by a computer. In this case, the functions may be implemented by recording a program for implementing these functions on a computer-readable recording medium, loading the program recorded on this recording medium into a computer system, and executing it. Here, "computer system" includes hardware such as an OS (Operating System) and peripheral devices. Furthermore, "computer-readable recording medium" refers to portable media such as flexible disks, magneto-optical disks, ROMs (Read Only Memory), CD-ROMs, and storage devices such as hard disks built into a computer system. Moreover, "computer-readable recording medium" may also include those that dynamically hold programs for a short period of time, such as communication lines used when transmitting programs via networks such as the Internet or communication lines such as telephone lines, and those that hold programs for a certain period of time, such as volatile memory inside a computer system that acts as a server or client in such cases. Furthermore, the above-mentioned program may be for implementing some of the functions described above, or it may be a program that can implement the above-mentioned functions in combination with a program already recorded in the computer system, or it may be implemented using a programmable logic device such as an FPGA.

[0067] Although the first to fourth embodiments of this invention have been described in detail above with reference to the drawings, the specific configuration is not limited to these embodiments and includes designs and the like that do not depart from the spirit of this invention.

[0068] The present invention can be applied to sensing systems, transmitting devices, programs, and sensing methods that require reducing power consumption in the transmitting device when sensing an object using a wireless signal transmitted from a transmitting device and received by a receiving device.

[0069] 10a, 10b, 10c, 10d... Optical signal generation unit, 11a, 11b, 11c, 11d... Weighting unit, 12a-1, 12a-2, ..., 12a-M, 12b-1, 12b-2, ..., 12b-M, 12c-1-1, 12c-1-2, ..., 12c-1-M, ..., 12c-N-1, 12c-N-2, ..., 12c-N-M, 12d-1, 12d-2, ..., 12d-M... Photo mixer, 13a-1, 13a-2, ..., 13a-M, 13b-1, 13b-2, ..., 13b-M, 13c-1-1, 13c-1-2, ..., 13c-1-M, ..., 13c-N-1, 13c-N-2, ..., 13c-N-M, 13d-1, 13d-2, ..., 13d-M... Transmitting antenna, 20a-1 to 20a-L, 20b-1 to 20b-L, 20c-1 to 20c-L, 20d-1 to 20d-L... Signal receiving unit, 21a, 21b, 21c, 21d... Sensing information acquisition unit, 100a, 100b, 100c, 100d... Transmitting device, 200a, 200b, 200c, 200d... Receiving device, 1000a, 1000b, 1000c, 1000d... Sensing System

Claims

1. A sensing system comprising a transmitting device and a receiving device, wherein the transmitting device comprises: an optical signal generating unit that generates an optical signal; an amplitude phase specifying unit that branches the optical signal generated by the optical signal generating unit into a plurality of optical signals and specifies the amplitude phase of each of the branched plurality of optical signals; a plurality of signal conversion units that convert the plurality of optical signals whose amplitude phases have been specified by the amplitude phase specifying unit into a plurality of electrical signals; and a plurality of transmitting antennas that wirelessly transmit the plurality of electrical signals converted by the plurality of signal conversion units, and the receiving device comprises: a plurality of receiving antennas that wirelessly receive the plurality of electrical signals transmitted from the plurality of transmitting antennas; and a sensing information acquisition unit that acquires information about an object to be sensed based on the plurality of electrical signals received by the plurality of receiving antennas.

2. A transmitting device comprising: an optical signal generation unit that generates an optical signal; an amplitude phase specification unit that branches the optical signal generated by the optical signal generation unit into a plurality of optical signals and specifies the amplitude phase of each of the branched plurality of optical signals; a plurality of signal conversion units that convert the plurality of optical signals whose amplitude phases have been specified by the amplitude phase specification unit into a plurality of electrical signals; and a plurality of transmitting antennas that wirelessly transmit the plurality of electrical signals converted by the plurality of signal conversion units.

3. A program that causes the computer of the transmitting device to execute: an optical signal generation process for generating an optical signal; an amplitude phase specification process for branching the optical signal generated in the optical signal generation process into a plurality of optical signals and specifying the amplitude phase of each of the branched plurality of optical signals; a signal conversion process for converting the plurality of optical signals whose amplitude phase has been specified in the amplitude phase specification process into a plurality of electrical signals; and a wireless transmission process for wirelessly transmitting the plurality of electrical signals converted in the signal conversion process from a plurality of transmitting antennas.

4. A sensing method using a transmitting device and a receiving device, comprising: an optical signal generation process in which the transmitting device generates an optical signal; an amplitude phase specification process in which the transmitting device branches the optical signal generated in the optical signal generation process into a plurality of optical signals and specifies the amplitude phase of each of the branched plurality of optical signals; a signal conversion process in which the transmitting device converts the plurality of optical signals whose amplitude phases have been specified in the amplitude phase specification process into a plurality of electrical signals; a wireless transmission process in which the transmitting device wirelessly transmits the plurality of electrical signals converted in the signal conversion process from a plurality of transmitting antennas; a wireless reception process in which the receiving device wirelessly receives the plurality of electrical signals transmitted from the plurality of transmitting antennas with a plurality of receiving antennas; and a sensing information acquisition process in which the receiving device acquires information about an object to be sensed based on the plurality of electrical signals received in the wireless reception process.

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