Transmitting device, receiving device, transmission control method, and reception control method

Abstract

The present invention provides a transmission device comprising: a plurality of frequency conversion circuits that convert analog signals obtained by modulating a plurality of baseband signals each having a bandwidth based on a baseband signal processing capability such that the analog signals include radio-frequency bands different from each other; and an OAM signal generation circuit that generates OAM signals by assigning the analog signals having been converted to include the radio-frequency bands different from each other, to different OAM modes, respectively.

Description

Technical Field

[0001] The present invention relates to a technique for spatially multiplexing wireless signals using the orbital angular momentum (OAM) of electromagnetic waves.

Background Art

[0002] In recent years, in order to improve the transmission capacity, studies on the spatial multiplexing transmission technology of wireless signals using OAM have been advanced. (For example, Non-Patent Document 1). The electromagnetic wave with OAM has an equiphase surface distributed in a helical shape along the propagation direction around the propagation axis. Electromagnetic waves with different OAM modes and propagating in the same direction have orthogonal spatial phase distributions in the direction of the rotation axis. Therefore, by separating signals of each OAM mode modulated with different signal sequences at the receiving station, it is possible to multiplex the signals.

[0003] In a wireless communication system using this OAM multiplexing technology, a uniform circular array antenna (hereinafter referred to as UCA) in which a plurality of antenna elements are circularly arranged at equal intervals is used, and a plurality of OAM modes are generated and synthesized for transmission, thereby realizing spatial multiplexing transmission of different signal sequences. (For example, Non-Patent Document 2). For example, a Butler circuit (Butler matrix circuit) is used for generating signals of a plurality of OAM modes.

[0004] Also, by using a multiple UCA in which a plurality of UCAs with different diameters are arranged concentrically, signals of the same OAM mode can be multiplexed and transmitted. On the receiving side, signals multiplexed within the same OAM mode can be separated by MIMO technology.

Prior Art Documents

Non-Patent Documents

[0005]

Non-Patent Document 1

[0006] Wireless communication using millimeter waves, sub-THz bands, etc., utilizes transmission bandwidths of several GHz, enabling high-capacity transmission. However, there is a problem in that the usable bandwidth is limited by the limitations of the digital signal processing capability of the baseband signal. For example, even if the transmission bandwidth is 10 GHz, if the digital signal processing capability is 2 GHz or less, the wide bandwidth cannot be utilized, and high-capacity transmission becomes difficult as only the band below 2 GHz is used. Another approach to utilize a wide bandwidth is to divide the band into 2 GHz increments, but this presents the problem of complex equipment configurations for signal separation and synthesis.

[0007] The disclosed technology aims to enable the use of high bandwidth with a simple device configuration. [Means for solving the problem]

[0008] The disclosed technology is a transmitting device that transmits a signal wider than the bandwidth by dividing the bandwidth according to the bandwidth based on the processing capability of the baseband signal, comprising: a plurality of modulation circuits that modulate a plurality of baseband signals divided according to the bandwidth based on the processing capability of the baseband signal into analog signals; a plurality of frequency conversion circuits that convert the plurality of analog signals modulated by the plurality of modulation circuits into a predetermined radio frequency band; and the predetermined Radio frequency band The transmitting device includes an OAM signal generation circuit that generates OAM signals by assigning multiple analog signals converted to each other to different OAM modes. [Effects of the Invention]

[0009] High bandwidth utilization can be achieved with a simple device configuration. [Brief explanation of the drawing]

[0010] [Figure 1] This is the first diagram illustrating a conventional transmitting and receiving device. [Figure 2] This is a second diagram illustrating a conventional transmitting and receiving device. [Figure 3] This is the first diagram to explain the conventional problems. [Figure 4] This is the second diagram, intended to explain the conventional problems. [Figure 5] This figure shows an example configuration of a communication system according to an embodiment of the present invention. [Figure 6] This figure shows an example of UCA phase setting for generating OAM mode signals. [Figure 7] This figure shows examples of phase distribution and signal intensity distribution of OAM multiplexed signals. [Figure 8] This figure shows an example configuration of a transmitting device according to Embodiment 1 of the present invention. [Figure 9] This figure shows an example configuration of a receiving device according to Embodiment 1 of the present invention. [Figure 10] This figure shows an example configuration of a transmitting device according to Embodiment 2 of the present invention. [Figure 11] This is a diagram showing a configuration example of a receiver according to Example 2 of the embodiments of the present invention. [Figure 12] This is a diagram showing an example of an antenna configuration including a plurality of UCAs arranged concentrically. [Figure 13] This is a diagram showing a configuration example of a transmitter according to Example 3 of the embodiments of the present invention. [Figure 14] This is a diagram showing a configuration example of a receiver according to Example 3 of the embodiments of the present invention. [Figure 15] This is a diagram showing a configuration example of a transmitter according to Example 4 of the embodiments of the present invention. [Figure 16] This is a diagram showing a configuration example of a receiver according to Example 4 of the embodiments of the present invention. [Figure 17] This is a diagram for explaining an OAM signal including polarization division multiplexing. [Figure 18] This is a diagram showing a configuration example of a transmitter according to Example 5 of the embodiments of the present invention. [Figure 19] This is a diagram showing a configuration example of a receiver according to Example 5 of the embodiments of the present invention. [Figure 20] This is a diagram showing a configuration example of a transmitter according to Example 6 of the embodiments of the present invention. [Figure 21] [[ID=​​​​​​​​​​​​​​​​​This figure shows an example of the configuration of a receiving device according to a modified example of Embodiment 8 of the present invention. [Figure 28] This figure shows an example configuration of a transmitting device according to Embodiment 9 of the present invention. [Figure 29] This figure shows an example configuration of a receiving device according to Embodiment 9 of the present invention. [Figure 30] This figure illustrates the effects of Example 9 of the embodiment of the present invention. [Figure 31] This sequence diagram shows an example of the control process flow according to Pattern 1 of the embodiment of the present invention. [Figure 32] This sequence diagram shows an example of the control process flow according to Pattern 2 of the embodiment of the present invention. [Figure 33] This sequence diagram shows an example of the control process flow according to Pattern 3 of the embodiment of the present invention. [Figure 34] This sequence diagram shows an example of the control process flow according to Pattern 4 of the embodiment of the present invention. [Modes for carrying out the invention]

[0011] Hereinafter, embodiments of the present invention (this embodiment) will be described with reference to the drawings. The embodiments described below are merely examples, and the embodiments to which the present invention is applied are not limited to the embodiments described below.

[0012] (Previous problems) First, let me explain the problems with the conventional approach.

[0013] Figure 1 is the first diagram illustrating a conventional transmitting and receiving device. A conventional transmitting device comprises a modulation circuit and a frequency conversion circuit. The modulation circuit modulates a baseband signal (digital signal) into an intermediate frequency (IF) analog signal. The frequency conversion circuit converts the frequency of the analog signal from the intermediate frequency to a radio frequency (RF). The transmitting device transmits the radio signal (radio wave) converted to radio frequency to the receiving device.

[0014] Conventional receiving devices also include a frequency conversion circuit and a demodulation circuit. The receiving device receives radio signals (radio waves) transmitted from the transmitting device. The frequency conversion circuit converts the frequency of the received signal from the radio frequency to an intermediate frequency. The demodulation circuit demodulates the analog signal at the intermediate frequency into a baseband signal.

[0015] Conventional transmitting and receiving devices are not designed to handle transmissions and receptions with bandwidths exceeding the processing capacity of their baseband signals. For example, if the baseband signal processing capacity of the transmitting and receiving device is 2 GHz or less, it can only handle signals with a bandwidth of 2 GHz or less.

[0016] Figure 2 is a second diagram illustrating a conventional transmitting and receiving device. Figure 2 shows an example of a transmitting and receiving device that transmits and receives a wideband signal by dividing the bandwidth into sections that represent the limit of the baseband signal processing capability (e.g., 2 GHz).

[0017] For example, the transmitting device modulates each digital signal, representing the bandwidth limit of the baseband signal processing capability (e.g., 2 GHz), into an intermediate frequency analog signal using a modulation circuit. The transmitting device then synthesizes the analog signals before or after conversion by the frequency conversion circuit, i.e., at the intermediate frequency or radio frequency.

[0018] Furthermore, the receiving device separates the analog signal before or after conversion by the frequency conversion circuit, i.e., at the intermediate frequency or radio frequency. The receiving device then demodulates each separated analog signal into a digital signal using a demodulation circuit to obtain baseband signals for each bandwidth (e.g., 2 GHz) that limits the processing capability of the baseband signal.

[0019] Thus, the transmission and reception shown in Figure 2 are achieved by combining signals by the transmitting device and separating signals by the receiving device. However, this presents the problem of circuit complexity, and in particular, it is difficult to implement the filters necessary for signal separation.

[0020] Figure 3 is the first diagram illustrating the problems of the conventional approach. In the configuration shown in Figure 2, for example, a band-pass filter (BPF) is required as a filter for signal separation in the receiving device. However, as shown in Figure 3, for example, separating signals in consecutive frequency slots requires high-precision separation performance capable of separating small frequency differences, which is difficult to achieve.

[0021] Figure 4 is a second diagram illustrating the conventional problems. As shown in Figure 4, it is conceivable that this can be achieved by setting a guard interval (GI) for each frequency slot to match the separation performance of the bandpass filter. However, setting such a guard interval for each frequency slot increases wasted bandwidth, resulting in a problem where the usable frequency bandwidth becomes narrower.

[0022] (Summary of this embodiment) To solve the conventional problems described above, this embodiment describes a method that combines OAM, which enables the synthesis and separation of multiple signals using analog circuits, with frequency division multiplexing (FDM), which divides and utilizes a wide bandwidth.

[0023] (Communication system configuration) First, the configuration of the communication system according to this embodiment will be described.

[0024] Figure 5 shows an example of the configuration of a communication system according to an embodiment of the present invention. The communication system comprises a transmitting device 100 and a receiving device 200.

[0025] The transmitting device 100 transmits an OAM signal to the receiving device 200. The transmitting device 100 comprises an antenna 110, a transmitting unit 120, and a transmitting control unit 130. The antenna 110 is composed of a uniform circular array antenna (UCA) or the like, capable of transmitting an OAM signal. The transmitting unit 120 transmits the OAM signal via the antenna 110.

[0026] The transmission control unit 130 controls the transmission of OAM signals by the transmission unit 120. For example, the transmission control unit 130 determines the bandwidth of the baseband signals to be assigned to each mode of the OAM signal.

[0027] The receiving device 200 receives the OAM signal transmitted from the transmitting device 100. The receiving device 200 comprises an antenna 210, a receiving unit 220, and a receiving control unit 230. The antenna 210 is composed of a UCA or the like capable of receiving the OAM signal. The receiving unit 220 receives the OAM signal via the antenna 210. The receiving control unit 230 controls the reception of the OAM signal by the receiving unit 220. For example, the receiving control unit 230 receives information indicating the assignment of each mode of the OAM signal (assignment information) from the transmitting control unit 130, and separates the received OAM signal into multiple signals with a bandwidth of 2 GHz or the like based on the received assignment information.

[0028] (Overview of OAM signals) Next, an overview of the OAM signal according to this embodiment will be described.

[0029] Figure 6 shows an example of UCA phase setting for generating an OAM mode signal. The UCA shown in Figure 6 consists of eight antenna elements.

[0030] In Figure 6, the OAM mode 0, 1, 2, 3, ... signals on the transmitting side are generated by the phase difference of the signals supplied to each antenna element of the UCA (indicated by ●). That is, the OAM mode n signal is generated by setting the phase of the signals supplied to each antenna element so that the phase rotates n times (n × 360 degrees). For example, if the UCA is composed of m = 8 antenna elements as shown in Figure 6, and a signal for OAM mode n = 2 is generated, then, as shown in Figure 6(3), a phase difference of 360n / m = 90 degrees counterclockwise (0 degrees, 90 degrees, 180 degrees, 270 degrees, 0 degrees, 90 degrees, 180 degrees, 270 degrees) is set for each antenna element so that the phase rotates twice.

[0031] Furthermore, OAM mode -n is defined as a signal with the phase rotation direction reversed compared to OAM mode n. For example, the phase rotation direction of a positive OAM mode signal is counterclockwise, and the phase rotation direction of a negative OAM mode signal is clockwise.

[0032] By generating different signal sequences as signals in different OAM modes and simultaneously transmitting the generated signals, wireless communication can be performed using spatial multiplexing. The transmitting side may pre-generate and combine the signals to be transmitted in each OAM mode and transmit the combined signal for each OAM mode using a single UCA, or it may use multiple UCAs and transmit the signals for each OAM mode using a different UCA for each OAM mode.

[0033] To separate the OAM multiplexed signals at the receiving end, the phase of each antenna element of the receiving UCA should be set to be in the opposite direction to the phase of the antenna elements of the transmitting end.

[0034] However, if interference occurs between OAM modes due to axial misalignment between the transmitting and receiving antennas, it becomes necessary to separate the OAM mode signals that have been mixed together by digital signal processing such as channel equalization and successive interference rejection. Interference between OAM modes refers to situations such as a signal transmitted from the transmitting device in OAM mode 1 being output as an OAM mode 2 signal at the receiving end.

[0035] Figure 7 shows examples of phase distribution and signal intensity distribution of OAM multiplexed signals. In Figures 7(1) and 7(2), the phase distributions of OAM mode 1 and OAM mode 2 signals, as viewed from the end face perpendicular to the propagation direction (propagation orthogonal plane) from the transmitting side, are represented by arrows. The beginning of the arrow is 0 degrees, and the phase changes linearly, ending at 360 degrees. That is, the OAM mode n signal propagates in the propagation orthogonal plane with a phase rotation of n (n × 360 degrees). Note that the arrows for the phase distribution of OAM modes -1 and -2 signals are in the opposite direction.

[0036] The signal intensity distribution and the position where the signal intensity is maximum differ for each OAM mode. However, the intensity distribution is the same for the same OAM mode but with different signs. Specifically, the higher the order of the OAM mode, the further the position where the signal intensity is maximum is from the propagation axis (Non-Patent Literature 2). Here, the OAM mode with a larger value is referred to as the higher-order mode. For example, the signal of OAM mode 3 is a higher-order mode than the signals of OAM mode 0, OAM mode 1, and OAM mode 2.

[0037] Figure 7(3) shows the positions where the signal strength is maximum for each OAM mode as indicated by rings. As the OAM mode is of a higher order, the position where the signal strength is maximum moves further from the central axis, and the beam diameter of the OAM mode multiplexed signal widens according to the propagation distance, causing the rings indicating the positions where the signal strength is maximum for each OAM mode to become larger.

[0038] Hereinafter, specific examples of this embodiment, from Example 1 to Example 9, will be described.

[0039] (Example 1) This embodiment describes an example of a transmitting device that simultaneously transmits multiple OAM mode signals by modulating multiple baseband signals into analog signals of different RF frequencies to generate signals of different OAM modes. It also describes an example of a receiving device that receives multiple OAM mode signals, separates the signals according to OAM mode, and demodulates each separated analog signal back into a baseband signal.

[0040] Figure 8 shows an example of the configuration of a transmitting device according to Embodiment 1 of the present invention. The transmitting unit 120 of the transmitting device 100 includes a plurality of modulation circuits 121 (modulation circuits 121-1, 121-2, ..., 121-n), a plurality of frequency conversion circuits 122 (frequency conversion circuits 122-1, 122-2, ..., 122-n), and an OAM signal generation circuit 123.

[0041] Each modulation circuit (modulation circuits 121-1, 121-2, ..., 121-n) modulates a digital signal, divided into bandwidths (e.g., 2 GHz) that represent the limit of the baseband signal processing capability, into an analog signal at an intermediate frequency.

[0042] Each frequency conversion circuit (frequency conversion circuits 122-1, 122-2, ..., 122-n) converts the frequency of each analog signal at an intermediate frequency to a radio frequency. The resulting radio frequencies are all different from each other and are input to the OAM signal generation circuit 123 so as to be assigned to different OAM modes (OAM mode #1, OAM mode #2, ..., OAM mode #n). For example, different OAM modes may be assigned to multiple frequency band blocks (for example, if 10 GHz is divided into 2 GHz segments, then five frequency blocks (F1-F5)).

[0043] In other words, multiple frequency conversion circuits (frequency conversion circuits 122-1, 122-2, ..., 122-n) each convert an analog signal modulated from multiple baseband signals, each having a bandwidth (e.g., 2 GHz) based on the processing capability of the baseband signal, so that it includes different radio frequency bands. Here, multiple frequency conversion circuits (frequency conversion circuits 122-1, 122-2, ..., 122-n) convert the modulated analog signal into different radio frequency bands.

[0044] The OAM signal generation circuit 123 is, for example, a Butler circuit (Butler matrix circuit). The OAM signal generation circuit 123 generates an OAM signal by synthesizing the input signals of each OAM mode having different frequencies, and transmits the generated OAM signal to the receiving device 200 via the antenna 110.

[0045] In other words, the OAM signal generation circuit 123 generates OAM signals in which analog signals converted to include different radio frequency bands are assigned to different OAM modes.

[0046] Figure 9 shows an example of the configuration of a receiving device according to Embodiment 1 of the present invention. The receiving unit 220 of the receiving device 200 includes a plurality of demodulation circuits 221 (demodulation circuits 221-1, 221-2, ..., 221-n), a plurality of frequency conversion circuits 222 (frequency conversion circuits 222-1, 222-2, ..., 222-n), and an OAM signal separation circuit 223.

[0047] The OAM signal separation circuit 223 is, for example, a Butler circuit (Butler matrix circuit). The OAM signal separation circuit 223 separates the OAM signal received via the antenna 210 into signals for each OAM mode, each having a different frequency.

[0048] In other words, the OAM signal separation circuit 223 separates OAM signals that are assigned to different OAM modes from analog signals that include different radio frequency bands. Here, the OAM signal separation circuit 223 separates OAM signals that are assigned to different OAM modes from analog signals that have been converted to different radio frequency bands.

[0049] Each frequency conversion circuit (frequency conversion circuits 222-1, 222-2, ..., 222-n) converts the frequency of each analog signal in the radio frequency range to an intermediate frequency.

[0050] Each demodulation circuit (demodulation circuits 221-1, 221-2, ..., 221-n) demodulates the analog signal, which has been converted to an intermediate frequency, back into a digital signal. This allows the receiving device 200 to obtain multiple baseband signals, each divided into bandwidths (e.g., 2 GHz) that represent the limit of its baseband signal processing capability.

[0051] In other words, multiple demodulation circuits (demodulation circuits 221-1, 221-2, ..., 221-n) demodulate the separated OAM signal into multiple baseband signals with bandwidths based on the baseband signal processing capability.

[0052] In this embodiment, the transmitting device 100 assigns multiple frequency-divided baseband signals to different OAM modes and combines them into an OAM signal. The receiving device 200 separates the received OAM signal to obtain multiple frequency-divided baseband signals. This makes it possible to utilize a wide bandwidth with a simple device configuration.

[0053] (Example 2) Embodiment 2 will be described below with reference to the drawings. Embodiment 2 differs from Embodiment 1 in that it assigns analog signals containing the same radio frequency to different OAM modes. Therefore, the following description of Embodiment 2 will focus on the differences from Embodiment 1, and components with the same functional configuration as in Embodiment 1 will be given the same reference numerals as those used in the description of Embodiment 1, and their explanations will be omitted.

[0054] Figure 10 shows an example of the configuration of a transmitting device according to Embodiment 2 of the present invention. The transmitting unit 120 of the transmitting device 100 according to this embodiment includes a plurality of modulation circuits 121 (modulation circuits 121-1-1, 121-1-2, ..., 121-n-1, 121-n-2), a plurality of frequency conversion circuits 122 (frequency conversion circuits 122-1-1, 122-1-2, ..., 122-n-1, 122-n-2), and an OAM signal generation circuit 123.

[0055] Each modulation circuit (modulation circuits 121-1-1, 121-1-2, ..., 121-n-1, 121-n-2) modulates a digital signal, divided into bandwidths (e.g., 2 GHz) that represent the limit of the baseband signal processing capability, into an analog signal at an intermediate frequency.

[0056] Each frequency conversion circuit (frequency conversion circuits 122-1-1, 122-1-2, ..., 122-n-1, 122-n-2) converts the frequency of each intermediate frequency analog signal to a radio frequency. The resulting radio frequencies may be the same (including overlapping) or different from each other.

[0057] For example, the radio frequencies converted by frequency conversion circuits 122-1-1 and 122-1-2 each contain the same frequency band. Furthermore, the radio frequencies converted by frequency conversion circuits 122-2-1 and 122-2-2 each contain the same frequency band and are different from the radio frequencies converted by frequency conversion circuits 122-1-1 and 122-1-2.

[0058] In other words, multiple frequency conversion circuits (frequency conversion circuits 122-1-1, 122-1-2, ..., 122-n-1, 122-n-2) convert the modulated analog signal so that it includes the same radio frequency band as each other.

[0059] The converted radio frequency signals are input to the OAM signal generation circuit 123 so that they are assigned to different OAM modes (OAM mode #1, OAM mode #-1, OAM mode #2, ..., OAM mode #n, OAM mode #0).

[0060] The OAM signal generation circuit 123 generates signals for each input OAM mode and transmits the generated OAM signals to the receiving device 200 via the antenna 110. In other words, the OAM signal generation circuit 123 generates OAM signals in which analog signals converted to include the same radio frequency band are assigned to different OAM modes.

[0061] The transmission control unit 130 determines which OAM mode to assign to which frequency slot. For example, the transmission control unit 130 may assign the same frequency band to multiple OAM modes with low interference between them, and assign different frequency bands to multiple OAM modes with high interference between them.

[0062] The transmission control unit 130 may assign the same number of OAM modes to the same frequency slot, or it may assign different numbers of OAM modes. For example, the transmission control unit 130 may assign OAM modes #-1, 2, and 0 to frequency slot #1 and OAM mode #-2 to frequency slot #2. Details on how the transmission control unit 130 assigns OAM modes will be described later.

[0063] Figure 11 shows an example of the configuration of a receiving device according to Embodiment 2 of the present invention. The receiving unit 220 of the receiving device 200 includes a plurality of demodulation circuits 221 (demodulation circuits 221-1-1, 221-1-2, ..., 221-n-1, 221-n-2), a plurality of frequency conversion circuits 222 (frequency conversion circuits 222-1-1, 222-1-2, ..., 222-n-1, 222-n-2), and an OAM signal separation circuit 223.

[0064] The OAM signal separation circuit 223 is, for example, a Butler circuit (Butler matrix circuit). The OAM signal separation circuit 223 separates the OAM signal received via the antenna 210 into signals for each OAM mode. The radio frequencies of the separated signals may be the same (including overlapping) frequencies or may be different frequencies.

[0065] In other words, the OAM signal separation circuit 223 separates the OAM signals, each assigned to a different OAM mode, from analog signals that have been converted to include the same radio frequency band.

[0066] Each frequency conversion circuit (frequency conversion circuits 222-1-1, 222-1-2, ..., 222-n-1, 222-n-2) converts the frequency of each analog signal in the radio frequency range to an intermediate frequency.

[0067] Each demodulation circuit (demodulation circuits 221-1-1, 221-1-2, ..., 221-n-1, 221-n-2) demodulates the analog signal, which has been converted to an intermediate frequency, back into a digital signal. This allows the receiving device 200 to obtain multiple baseband signals, each divided into bandwidths (e.g., 2 GHz) that represent the limit of its baseband signal processing capability.

[0068] In this embodiment, multiple analog signals sharing some radio frequencies are assigned to different OAM modes. This enables wideband transmission and reception by utilizing the phase difference which reduces interference from OAM multiplexing, and allows for efficient use of bandwidth.

[0069] (Example 2-2) Furthermore, the transmission control unit 130 may assign the signal with higher priority from among the multiple signals to a dedicated OAM mode or dedicated frequency. The transmission control unit 130 may also assign the signal with lower priority from among the multiple signals to a shared OAM mode or the same (partially overlapping) frequency band. For example, in the example shown in Figure 8, if signal #1 is to be given priority over signals #2, #3, ..., #2n, OAM mode #1 may be designated as a dedicated channel, and OAM modes #-1, #2, ..., #0 may be designated as a shared channel. In this case, the dedicated channel OAM mode #1 may use a different frequency band from the other channels.

[0070] In this case, multiple frequency conversion circuits (frequency conversion circuits 222-1-1, 222-1-2, ..., 222-n-1, 222-n-2) convert the modulated analog signal by determining, according to the priority of the multiple baseband signals, whether to use a radio frequency band different from other OAM modes or a radio frequency band that includes the same radio frequency band as other OAM modes.

[0071] The transmission control unit 130 may dynamically assign each signal to either a dedicated channel or a shared channel depending on the nature of the signal and the channel status. This makes it possible to achieve assignments that match the nature of the signal.

[0072] (Example 3) Embodiment 3 will be described below with reference to the drawings. Embodiment 3 differs from Embodiment 1 in that it uses the OAM multiplexing method to transmit and receive signals. Therefore, the following description of Embodiment 3 will focus on the differences from Embodiment 1, and components with the same functional configuration as Embodiment 1 will be given the same symbols used in the description of Embodiment 1, and their explanation will be omitted.

[0073] First, let's explain UCA in the OAM multiplexing scheme. Figure 12 shows an example of an antenna configuration with multiple UCAs arranged concentrically. As shown in Figure 12, a multiplexed UCA, in which multiple UCAs of different diameters are arranged concentrically, can transmit signals of the same OAM mode multiplexed. On the receiving end, MIMO technology can be used to separate the signals multiplexed within the same OAM mode. Figure 12 shows an example of a multiplexed UCA with four UCAs of different diameters arranged concentrically.

[0074] Figure 13 shows an example of the configuration of a transmitting device according to Embodiment 3 of the present invention. The transmitting unit 120 of the transmitting device 100 includes a plurality of modulation circuits 121 (modulation circuits 121-1-1, 121-1-2, ..., 121-n-1, 121-n-2), a plurality of frequency conversion circuits 122 (frequency conversion circuits 122-1-1, 122-1-2, ..., 122-n-1, 122-n-2), and a plurality of OAM signal generation circuits 123 (OAM signal generation circuits 123-1, 123-2).

[0075] Each modulation circuit (modulation circuits 121-1-1, 121-1-2, ..., 121-n-1, 121-n-2) modulates a digital signal, divided into bandwidths (e.g., 2 GHz) that represent the limit of the baseband signal processing capability, into an analog signal at an intermediate frequency.

[0076] Each frequency conversion circuit (frequency conversion circuits 122-1-1, 122-1-2, ..., 122-n-1, 122-n-2) converts the frequency of each intermediate frequency analog signal to a radio frequency. The resulting radio frequencies may be the same (including overlapping) or different from each other.

[0077] For example, the radio frequencies converted by frequency conversion circuits 122-1-1 and 122-1-2 each contain the same frequency band. Furthermore, the radio frequencies converted by frequency conversion circuits 122-2-1 and 122-2-2 each contain the same frequency band and are different from the radio frequencies converted by frequency conversion circuits 122-1-1 and 122-1-2.

[0078] Each converted radio frequency signal may contain the same OAM mode assigned to a different UCA by OAM multiplexing. For example, signal #1 is assigned to OAM mode #1 of UCA #1. Signal #2 is assigned to OAM mode #1 of UCA #2. Signal #3 is assigned to OAM mode #2 of UCA #1. Signal #4 is assigned to OAM mode #2 of UCA #2. Of these, for the same UCA, they are each different frequencies and assigned to different OAM modes.

[0079] Each OAM signal generation circuit 123 (OAM signal generation circuits 123-1, 123-2) generates signals for each OAM mode having different frequencies that are input to it, and transmits the generated OAM signals to the receiving device 200 via each UCA of the antenna 110.

[0080] In other words, each OAM signal generation circuit 123 (OAM signal generation circuits 123-1, 123-2) is assigned to multiple UCAs, and the analog signals converted to different radio frequency bands for each UCA are used to generate OAM multiplexed signals, each assigned to a different OAM mode.

[0081] Antenna 110 is an antenna capable of OAM multiplexing, and for example, has a multiple concentric uniform circular array (M-UCA) containing multiple UCAs. Although Figure 13 shows an example with two UCAs, the number of UCAs may be three or more.

[0082] Figure 14 shows an example of the configuration of a receiving device according to Embodiment 3 of the present invention. The receiving unit 220 of the receiving device 200 includes a plurality of demodulation circuits 221 (demodulation circuits 221-1-1, 221-1-2, ..., 221-n-1, 221-n-2), a plurality of frequency conversion circuits 222 (frequency conversion circuits 222-1-1, 222-1-2, ..., 222-n-1, 222-n-2), and a plurality of OAM signal separation circuits 223 (OAM signal separation circuits 223-1, 223-2).

[0083] Antenna 210 is an OAM multiplexed reception antenna and has multiple UCAs, for example, including multiple UCAs. Although Figure 14 shows an example with two UCAs, the number of UCAs may be three or more.

[0084] Each OAM signal separation circuit (OAM signal separation circuits 223-1, 223-2) separates the OAM signals received via each UCA of the antenna 210 into signals for each OAM mode, each having a different frequency.

[0085] In other words, each OAM signal separation circuit (OAM signal separation circuits 223-1, 223-2) is assigned to multiple UCAs, and the analog signals converted to different radio frequency bands for each UCA within the multiple UCAs separate the OAM multiplexed signals that are assigned to different OAM modes.

[0086] Each frequency conversion circuit (frequency conversion circuits 222-1-1, 222-1-2, ..., 222-n-1, 222-n-2) converts the frequency of each analog signal in the radio frequency range to an intermediate frequency.

[0087] Each demodulation circuit (demodulation circuits 221-1-1, 221-1-2, ..., 221-n-1, 221-n-2) demodulates the analog signal, which has been converted to an intermediate frequency, back into a digital signal. This allows the receiving device 200 to obtain multiple baseband signals, each divided into bandwidths (e.g., 2 GHz) that represent the limit of its baseband signal processing capability.

[0088] According to this embodiment, the transmitting device 100 transmits and receives signals using the OAM multiplexing method. This allows for more effective use of the frequency band in wideband wireless communication by utilizing the multiplexed OAM mode signals.

[0089] (Example 4) Embodiment 4 will be described below with reference to the drawings. Embodiment 4 differs from Embodiment 2 in that it uses the OAM multiplexing method to transmit and receive signals. Therefore, the following description of Embodiment 4 will focus on the differences from Embodiment 2, and components with the same functional configuration as Embodiment 2 will be given the same symbols used in the description of Embodiment 2, and their explanation will be omitted.

[0090] Figure 15 shows an example of the configuration of a transmitting device according to Embodiment 4 of the present invention. The transmitting unit 120 of the transmitting device 100 includes a plurality of transmitting circuits 120-1, 120-2 having the same configuration as the transmitting unit 120 shown in Embodiment 2. The antenna 110 also has a plurality of UCAs (UCA#1, #2).

[0091] Transmitting circuit 120-1 generates the signal transmitted from UCA#1. Transmitting circuit 120-2 generates the signal transmitted from UCA#2. The radio frequencies converted by each transmitting circuit (transmitting circuits 120-1, 120-2) may be the same (including overlapping) frequencies as in Example 2, or they may be different frequencies.

[0092] Each transmitting circuit (transmitting circuits 120-1, 120-2) includes an OAM signal generation circuit 123 which is assigned to multiple UCAs. The analog signals, converted to include the same radio frequency band for each UCA, are then used to generate OAM multiplexed signals, each assigned to a different OAM mode.

[0093] Figure 16 shows an example of the configuration of a receiving device according to Embodiment 4 of the present invention. The receiving unit 220 of the receiving device 200 includes a plurality of receiving circuits 220-1, 220-2 having the same configuration as the receiving unit 220 shown in Embodiment 2. The antenna 210 also has a plurality of UCAs (UCA#1, #2).

[0094] Receiving circuit 220-1 processes the signal received by UCA#1. Receiving circuit 220-2 processes the signal received by UCA#2. The radio frequencies of the signals separated by each receiving circuit (receiving circuits 220-1, 220-2) may be the same (including overlapping) frequencies as in Embodiment 2, or they may be different frequencies.

[0095] The OAM signal separation circuit 223, included in multiple receiving circuits 220-1 and 220-2, separates the OAM multiplexed signals, each assigned to a different OAM mode, from analog signals that have been converted to include the same radio frequency band for each UCA within the multiple UCAs.

[0096] In this embodiment, the transmitting device 100 assigns multiple analog signals with some radio frequencies sharing the same frequency to different OAM modes and transmits and receives signals using an OAM multiplexing scheme. This allows for more effective use of the frequency band in wireless communication utilizing a wide bandwidth.

[0097] (Example 5) Embodiment 5 will be described below with reference to the drawings. Embodiment 5 differs from Embodiments 1 or 2 in that it uses polarization division multiplexing to transmit and receive OAM signals. Therefore, the following description of Embodiment 5 will focus on the differences from Embodiments 1 or 2, and components having the same functional configuration as Embodiments 1 or 2 will be given the same reference numerals as those used in the description of Embodiments 1 or 2, and their explanation will be omitted.

[0098] First, the OAM signal using Polarization Division Multiplexing (PDM) according to this embodiment will be described. The OAM signal using Polarization Division Multiplexing is an OAM signal that is transmitted by multiplexing two polarizations having a phase difference of 90 degrees into different OAM modes.

[0099] Figure 17 is a diagram illustrating an OAM signal including polarization division multiplexing. Figure 17 shows that antenna elements 211 and 212, which are part of the antenna 210 of the receiving device 200, are located at a specified distance (e.g., 1 cm) apart.

[0100] For example, in Figure 17, the phase of a radio wave with OAM mode 3 transmitted from the transmitter 100 is shown in circle 901. The center position 902 of circle 901 is on the central axis (propagation axis) 903 of the radio wave of that OAM mode transmitted from the transmitter 100.

[0101] In the example shown in Figure 17, antenna elements 211 and 212 are positioned 30 degrees apart from the center position 902. Therefore, for radio waves with an OAM mode of +3, the phase rotation is 3, and the difference between the phase at the position of antenna element 211 and the phase at the position of antenna element 212 is 90 degrees (= 30 degrees × 3). The receiving control unit 230 of the receiving device 200 may then extract the characteristics of each signal by combining these two signals with a phase difference of 90 degrees.

[0102] For example, if the phase difference between the positive OAM mode signals of antenna element 211 and antenna element 212 is 90 degrees, the phase difference between the negative OAM mode signals will be -90 degrees. Therefore, when the receiving control unit 230 combines the signal received by antenna element 211 with the signal received by antenna element 212 rotated by 90 degrees in phase, only the negative OAM mode signal is output. When the receiving control unit 230 combines the signal received by antenna element 211 with the signal received by antenna element 212 rotated by -90 degrees in phase, only the positive OAM mode signal is output.

[0103] As a result, the receiving device 200 can reduce its computational load because it does not need to perform some of the signal separation processing between OAM modes.

[0104] Figure 18 shows an example of the configuration of a transmitting device according to Embodiment 5 of the present invention. The transmitting unit 120 of the transmitting device 100 includes a plurality of transmitting circuits 120-1, 120-2 having the same configuration as the transmitting unit 120 shown in Embodiment 1 or 2.

[0105] Antenna 110 has a configuration in which antenna elements for each polarization are arranged alternately. Specifically, the UCA of antenna 110 has antenna elements for X polarization (XPol) and antenna elements for Y polarization (YPol) arranged alternately. A UCA composed of antenna elements for X polarization (XPol) may be called an X-polarization (XPol) UCA. Similarly, a UCA composed of antenna elements for Y polarization (YPol) may be called a Y-polarization (YPol) UCA. Antenna 110 may also have antenna elements that can be used for both X polarization (XPol) and Y polarization (YPol).

[0106] Transmitting circuit 120-1 generates an X-polarized (XPol) signal. The signal generated by transmitting circuit 120-1 is transmitted via a UCA for X-polarized (XPol). On the other hand, transmitting circuit 120-2 generates a Y-polarized (YPol) signal. The signal generated by transmitting circuit 120-2 is transmitted via a UCA for Y-polarized (YPol).

[0107] In other words, multiple transmitting circuits (transmitting circuits 120-1, 120-2) generate OAM signals with different polarizations between each transmitting circuit.

[0108] Figure 19 shows an example of the configuration of a receiving device according to Embodiment 5 of the present invention. The receiving unit 220 of the receiving device 200 includes a plurality of receiving circuits 220-1, 220-2 having the same configuration as the receiving unit 220 shown in Embodiment 1 or 2.

[0109] Furthermore, the UCA of antenna 210 has antenna elements for X polarization (XPol) and antenna elements for Y polarization (YPol) arranged alternately. A UCA composed of antenna elements for X polarization (XPol) may be called an X-polarization (XPol) UCA. Similarly, a UCA composed of antenna elements for Y polarization (YPol) may be called a Y-polarization (YPol) UCA. Antenna 210 may also have antenna elements that can be used for both X polarization (XPol) and Y polarization (YPol).

[0110] Receiver circuit 220-1 processes the signal received by the UCA for X polarization (XPol). Receiver circuit 220-2 processes the signal received by the UCA for Y polarization (YPol). In other words, the multiple receiver circuits (receivers 220-1 and 220-2) separate OAM signals with different polarizations from each other.

[0111] According to this embodiment, OAM signals including polarization division multiplexing are transmitted and received. This reduces the computational load required for signal separation processing by the receiving device 200.

[0112] (Example 6) Embodiment 6 will be described below with reference to the drawings. Embodiment 6 differs from Embodiments 3 or 4 in that it transmits and receives OAM signals including polarization division multiplexing. Therefore, the following description of Embodiment 6 will focus on the differences from Embodiments 3 or 4, and components having the same functional configuration as Embodiments 3 or 4 will be given the same symbols used in the description of Embodiments 3 or 4, and their explanation will be omitted.

[0113] Figure 20 shows an example of the configuration of a transmitting device according to Embodiment 6 of the present invention. The transmitting unit 120 of the transmitting device 100 includes a plurality of transmitting circuits 120-1, 120-2 having the same configuration as the transmitting unit 120 shown in Embodiment 3 or 4.

[0114] Antenna 110 is an antenna capable of OAM multiplexing, and for example, has a multiplexed UCA that includes multiple UCAs. Each UCA included in the multiplexed UCA has a configuration in which antenna elements for each polarization are arranged alternately. Specifically, each UCA included in the multiplexed UCA has antenna elements for X polarization (XPol) and antenna elements for Y polarization (YPol) arranged alternately. A UCA composed of antenna elements for X polarization (XPol) may be called an X polarization (XPol) UCA. Similarly, a UCA composed of antenna elements for Y polarization (YPol) may be called a Y polarization (YPol) UCA. Antenna 110 may also have antenna elements that can be used for both X polarization (XPol) and Y polarization (YPol).

[0115] For example, antenna 110 includes UCA#1 for X polarization (XPol), UCA#1 for Y polarization (YPol), UCA#2 for X polarization (XPol), and UCA#2 for Y polarization (YPol).

[0116] Note that Figure 20 shows an example where there are two UCAs for each polarization, but there may be three or more UCAs for each polarization.

[0117] Transmitting circuit 120-1 generates an X-polarized (XPol) signal. The signal generated by transmitting circuit 120-1 is transmitted via UCA#1 and UCA#2 for X-polarized (XPol). On the other hand, transmitting circuit 120-2 generates a Y-polarized (YPol) signal. The signal generated by transmitting circuit 120-2 is transmitted via UCA#1 and UCA#2 for Y-polarized (YPol).

[0118] In other words, multiple transmitting circuits (transmitting circuits 120-1, 120-2) generate OAM signals with different polarizations between each transmitting circuit.

[0119] Figure 21 shows an example of the configuration of a receiving device according to Embodiment 6 of the present invention. The receiving unit 220 of the receiving device 200 includes a plurality of receiving circuits 220-1, 220-2 having the same configuration as the receiving unit 220 shown in Embodiment 3 or 4.

[0120] Antenna 210 is an antenna capable of OAM multiplexing, and for example, has a multiplexed UCA that includes multiple UCAs. Each UCA included in the multiplexed UCA has a configuration in which antenna elements for each polarization are arranged alternately. Specifically, each UCA included in the multiplexed UCA has antenna elements for X polarization (XPol) and antenna elements for Y polarization (YPol) arranged alternately. A UCA composed of antenna elements for X polarization (XPol) may be called an X polarization (XPol) UCA. Similarly, a UCA composed of antenna elements for Y polarization (YPol) may be called a Y polarization (YPol) UCA. Antenna 210 may also have antenna elements that can be used for both X polarization (XPol) and Y polarization (YPol).

[0121] For example, antenna 210 includes UCA#1 for X polarization (XPol), UCA#1 for Y polarization (YPol), UCA#2 for X polarization (XPol), and UCA#2 for Y polarization (YPol).

[0122] Receiver circuit 220-1 processes the signals received by UCA#1 for X polarization (XPol) and UCA#2 for X polarization (XPol). Receiver circuit 220-2 processes the signals received by UCA#1 for Y polarization (YPol) and UCA#2 for Y polarization (YPol). In other words, the multiple receiver circuits (receivers 220-1 and 220-2) separate OAM signals with different polarizations from each other.

[0123] According to this embodiment, OAM signals are transmitted and received using OAM multiplexing and polarization division multiplexing. This reduces the computational load required for signal separation processing by the receiving device 200, while enabling more effective use of the frequency band in wideband wireless communication.

[0124] (Example 7) Embodiment 7 will be described below with reference to the drawings. Embodiment 7 differs from Embodiments 1 to 6 in that it uses Time Division Multiplexing (TDM) to transmit and receive signals. Therefore, the following description of Embodiment 7 will focus on the differences from Embodiments 1 to 6, and components with a similar functional configuration to any of Embodiments 1 to 6 will be assigned the same reference numerals as those used in the descriptions of Embodiments 1 to 6, and their descriptions will be omitted.

[0125] An OAM signal using time-division multiplexing is an OAM signal that is transmitted by multiplexing multiple time-division signals into different OAM modes.

[0126] Figure 22 shows an example of the configuration of a transmitting device according to Embodiment 7 of the present invention. The transmitting unit 120 of the transmitting device 100 comprises a plurality of transmitting circuits 120-1, 120-2, ..., 120-n having the same configuration as the transmitting unit 120 shown in any of Embodiments 1 to 6, and a signal combining circuit 124.

[0127] Each transmitting circuit (transmitting circuits 120-1, 120-2, ..., 120-n) generates signals for n time-divided time slots. For example, transmitting circuit 120-1 generates the signal for time slot #1, transmitting circuit 120-2 generates the signal for time slot #2, and transmitting circuit 120-n generates the signal for time slot #n.

[0128] In other words, multiple transmitting circuits (transmitting circuits 120-1, 120-2, ..., 120-n) generate OAM signals with different time slots between each transmitting circuit.

[0129] The signal combining circuit 124 combines the signals generated by each transmitting circuit (transmitting circuits 120-1, 120-2, ..., 120-n).

[0130] Antenna 110 has a configuration similar to that of antenna 110 shown in any of Examples 1 to 6, corresponding to each transmitting circuit (transmitting circuits 120-1, 120-2, ..., 120-n). For example, if each transmitting circuit (transmitting circuits 120-1, 120-2, ..., 120-n) has a configuration similar to that of the transmitting unit 120 shown in Example 6, then antenna 110 has a configuration similar to that of antenna 110 shown in Example 6, as shown in Figure 22.

[0131] The transmission control unit 130 of the transmission device 100 may dynamically determine the number n of time slots and the length of each time slot according to channel information, etc., or it may determine them in a predetermined way.

[0132] Figure 23 shows an example of the configuration of a receiving device according to Embodiment 7 of the present invention. The receiving unit 220 of the receiving device 200 comprises a plurality of receiving circuits 220-1, 220-2, ..., 220-n having the same configuration as the receiving unit 220 shown in any of Embodiments 1 to 6, and a signal separation circuit 224.

[0133] Antenna 210 has a configuration similar to that of Antenna 210 shown in any of Examples 1 to 6, corresponding to each receiving circuit (receiving circuits 220-1, 220-2, ..., 220-n). For example, if each receiving circuit (receiving circuits 220-1, 220-2, ..., 220-n) has a configuration similar to that of the receiving unit 220 shown in Example 6, then Antenna 210 has a configuration similar to that of Antenna 210 shown in Example 6, as shown in Figure 23.

[0134] The signal separation circuit 224 separates the signal received by the antenna 210 for each receiving circuit (receiving circuits 220-1, 220-2, ..., 220-n). The separated signals are each time-divided into n time slots.

[0135] Each receiving circuit (receiving circuits 220-1, 220-2, ..., 220-n) processes signals from time slots that are divided into n time divisions. For example, receiving circuit 220-1 processes the signal from time slot #1, receiving circuit 220-2 processes the signal from time slot #2, and receiving circuit 220-n processes the signal from time slot #n.

[0136] In other words, multiple receiving circuits (receiving circuits 220-1, 220-2, ..., 220-n) separate OAM signals with different time slots from each other.

[0137] According to this embodiment, OAM signals are transmitted and received using time-division multiplexing. This allows for effective use of the time domain in addition to the frequency band in wireless communication using a wide bandwidth.

[0138] (Example 8) Embodiment 8 will be described below with reference to the drawings. Embodiment 8 differs from Embodiments 1 to 7 in that it transmits and receives signals using an extended radio frequency band. Therefore, the following description of Embodiment 8 will focus on the differences from Embodiments 1 to 7, and components having a similar functional configuration to any of Embodiments 1 to 7 will be given the same reference numerals as those used in the descriptions of Embodiments 1 to 7, and their descriptions will be omitted.

[0139] Figure 24 shows an example of the configuration of a transmitting device according to Embodiment 8 of the present invention. The transmitting unit 120 of the transmitting device 100 comprises a plurality of transmitting circuits 120-1, 120-2 having the same configuration as the transmitting unit 120 shown in any of Embodiments 1 to 7, and a signal combining circuit 124.

[0140] Each transmitting circuit (transmitting circuits 120-1 and 120-2) generates signals in different radio frequency bands. For example, transmitting circuit 120-1 generates signals in the radio frequency band from 140 GHz to 150 GHz (RF band #1). Transmitting circuit 120-2 generates signals in the radio frequency band from 150 GHz to 160 GHz (RF band #2).

[0141] In other words, multiple transmitting circuits (transmitting circuits 120-1, 120-2) generate OAM signals in different radio frequency bands between each transmitting circuit.

[0142] The signal combining circuit 124 combines the signals generated by each transmitting circuit (transmitting circuits 120-1 and 120-2).

[0143] Antenna 110 has a configuration similar to that of Antenna 110 shown in any of Examples 1 to 7, corresponding to each transmitting circuit (transmitting circuits 120-1, 120-2, ..., 120-n). For example, if each transmitting circuit (transmitting circuits 120-1, 120-2, ..., 120-n) has a configuration similar to that of the transmitting unit 120 shown in Example 6, then Antenna 110 has a configuration similar to that of Antenna 110 shown in Example 6, as shown in Figure 24.

[0144] Note that Figure 24 shows an example where there are two radio frequency bands, but there may be three or more radio frequency bands.

[0145] Figure 25 shows an example of the configuration of a receiving device according to Embodiment 8 of the present invention. The receiving unit 220 of the receiving device 200 comprises a plurality of receiving circuits 220-1, 220-2 having the same configuration as the receiving unit 220 shown in any of Embodiments 1 to 7, and a signal separation circuit 224.

[0146] Antenna 210 has a configuration similar to that of antenna 210 shown in any of Examples 1 to 7, corresponding to each receiving circuit (receiving circuits 220-1, 220-2). For example, if each receiving circuit (receiving circuits 220-1, 220-2) has a configuration similar to that of the receiving unit 220 shown in Example 6, then antenna 210 has a configuration similar to that of antenna 210 shown in Example 6, as shown in Figure 25.

[0147] The signal separation circuit 224 separates the signal received by the antenna 210 for each receiving circuit (receiving circuits 220-1, 220-2) using a filter such as a bandpass filter. The separated signals are each in different radio frequency bands.

[0148] Each receiving circuit (receiving circuits 220-1 and 220-2) processes signals in different radio frequency bands. For example, receiving circuit 220-1 processes signals in the radio frequency band from 140 GHz to 150 GHz (RF band #1), and receiving circuit 220-2 processes signals in the radio frequency band from 150 GHz to 160 GHz (RF band #2).

[0149] In other words, multiple receiving circuits (receiving circuits 220-1, 220-2) generate OAM signals in different radio frequency bands between each receiving circuit.

[0150] (Modified version of Example 8) As a variation of Example 8, the signals of each radio frequency band may be combined using a conventional combining method before being input to the OAM signal generation circuit (e.g., Butler circuit).

[0151] Figure 26 shows an example of the configuration of a transmitting device according to a modified example of Embodiment 8 of the present invention. The transmitting unit 120 of the transmitting device 100 according to this modified example further includes an OAM signal generation circuit 125 in addition to the configuration of the transmitting device 100 according to Embodiment 8.

[0152] The OAM signal generation circuit 125 is, for example, a Butler circuit (Butler matrix circuit). The OAM signal generation circuit 125 generates signals for each OAM mode from the signals synthesized by the signal synthesis circuit 124, and transmits the generated OAM signals to the receiving device 200 via the antenna 110.

[0153] Figure 27 shows an example of the configuration of a receiving device according to a modified example of Embodiment 8 of the present invention. The receiving unit 220 of the receiving device 200 according to this modified example further includes an OAM signal separation circuit 225 in addition to the configuration of the transmitting device 100 according to Embodiment 8.

[0154] The OAM signal separation circuit 225 is, for example, a Butler circuit (Butler matrix circuit). The OAM signal separation circuit 225 separates the OAM signal received via the antenna 210 into signals for each OAM mode, each having a different frequency.

[0155] The signal separation circuit 224 separates the signals for each OAM mode for each receiving circuit (receiving circuits 220-1, 220-2) using a filter such as a bandpass filter. The separated signals are each in different radio frequency bands.

[0156] According to this embodiment, OAM signals are transmitted and received using an extended radio frequency band. This makes it possible to utilize an even more extended radio frequency band in wireless communication that uses a wide bandwidth.

[0157] (Example 9) Embodiment 9 will be described below with reference to the drawings. Embodiment 9 differs from Embodiments 1 to 8 in that it uses both a conventional transceiver and a transceiver as shown in Embodiments 1-8. Therefore, in the following description of Embodiment 9, the differences from Embodiments 1 to 8 will be the main focus, and components having a similar functional configuration to any of Embodiments 1 to 8 will be given the same reference numerals as those used in the descriptions of Embodiments 1 to 8, and their descriptions will be omitted.

[0158] Figure 28 shows an example of the configuration of a transmitting device according to Embodiment 9 of the present invention. The transmitting unit 120 of the transmitting device 100 includes a plurality of transmitting circuits (transmitting circuits 120-1, 120-2, ..., 120-n) and a signal combining circuit 124.

[0159] Each transmitting circuit (transmitting circuits 120-1, 120-2, ..., 120-n) comprises multiple modulation circuits, multiple frequency conversion circuits, and an OAM signal generation circuit. For example, transmitting circuit 120-1 comprises multiple modulation circuits (modulation circuits 121-1-1, 121-1-2), multiple frequency conversion circuits (frequency conversion circuits 122-1-1, 122-1-2), and an OAM signal generation circuit 123-1.

[0160] Similarly, the transmitting circuit 120-2 includes a plurality of modulation circuits (modulation circuits 121-2-1, 121-2-2), a plurality of frequency conversion circuits (frequency conversion circuits 122-2-1, 122-2-2), and an OAM signal generation circuit 123-2. The transmitting circuit 120-n includes a plurality of modulation circuits (modulation circuits 121-n-1, 121-n-2), a plurality of frequency conversion circuits (frequency conversion circuits 122-n-1, 122-n-2), and an OAM signal generation circuit 123-n.

[0161] Each transmitting circuit (transmitting circuits 120-1, 120-2, ..., 120-n) has the same configuration as the transmitting unit 120 of the transmitting device 100 according to any of Examples 1 to 8, and generates OAM signals by assigning signals from multiple adjacent frequency band blocks to each OAM mode. On the other hand, a guard interval is provided between signals generated by different transmitting circuits for each frequency slot.

[0162] For example, signals #1 and #2 generated by the transmitting circuit 120-1 are signals in adjacent radio frequency bands. On the other hand, signals #2 generated by the transmitting circuit 120-1 and signal #3 generated by the transmitting circuit 120-2 are signals in radio frequency bands with a guard interval between them.

[0163] In other words, multiple transmitting circuits (transmitting circuits 120-1, 120-2, ..., 120-n) are in adjacent radio frequency bands, and the analog signals converted to these bands, with guard intervals provided between each transmitting circuit, generate OAM signals that are each assigned to different OAM modes.

[0164] The signal combining circuit 124 combines the signals generated by each transmitting circuit (transmitting circuits 120-1, 120-2, ..., 120-n).

[0165] The transmission control unit 130 of the transmission device 100 may determine the number of consecutive frequency slots, the filter width, the guard interval width, etc., using predetermined parameters, or it may determine them variably using channel information, etc.

[0166] Figure 29 shows an example of the configuration of a receiving device according to Embodiment 9 of the present invention. The receiving unit 220 of the receiving device 200 includes a plurality of receiving circuits (receiving circuits 220-1, 220-2, ..., 220-n) and a signal separation circuit 224.

[0167] The signal separation circuit 224 separates the signal received by the antenna 210 for each receiving circuit (receiving circuits 220-1, 220-2, ..., 220-n). The separated signals are each signals in adjacent radio frequency bands.

[0168] Each receiving circuit (receiving circuits 220-1, 220-2, ..., 220-n) has the same configuration as the receiving unit 220 of the receiving device 200 according to any of Examples 1 to 8, and processes the signals of multiple adjacent frequency band blocks in the radio frequency bands, which are OAM signals assigned to each OAM mode.

[0169] In other words, multiple receiving circuits (receiving circuits 220-1, 220-2, ..., 220-n) separate the analog signals converted to radio frequency bands that are adjacent to each other and have guard intervals between them, each of which is assigned to a different OAM mode.

[0170] Figure 30 is a diagram illustrating the effects of Embodiment 9 of the present invention. According to this embodiment, for signals in multiple adjacent frequency band blocks of radio frequency bands, signals generated by an OAM signal generation circuit are transmitted and received. This makes it possible to separate signals using the characteristics of the OAM signal. For example, signals #1 and #2 shown in Figure 30 are generated by an OAM signal generation circuit included in each transmission circuit of the transmitter 100 and separated by an OAM signal separation circuit included in each reception circuit of the receiver 200.

[0171] Furthermore, according to this embodiment, for signals in multiple frequency band blocks with guard intervals, signals synthesized by a conventional signal synthesis circuit are transmitted and separated by a signal separation circuit. For example, signals #2 and #3 shown in Figure 30 are synthesized by the signal synthesis circuit of the transmitting device 100 and separated by the signal separation circuit of the receiving device 200.

[0172] Therefore, according to this embodiment, by utilizing the characteristics of OAM signals, particularly for multiple adjacent frequency band blocks, wireless communication using a wide bandwidth can be realized with a more flexible device configuration.

[0173] (Operation of the communication system) Next, the operation of the communication system common to each embodiment from Example 1 to Example 9 will be described with reference to the drawings. The communication system may operate in one of the following four patterns.

[0174] (Pattern 1) Pattern 1 is an open-loop control pattern in which channel information and other data are not fed back from the receiving control unit 230 to the transmitting control unit 130.

[0175] Figure 31 is a sequence diagram showing an example of the control process flow according to Pattern 1 of an embodiment of the present invention. The transmission control unit 130 of the transmitting device 100 determines the signal assignment (step S101). For example, the transmission control unit 130 determines which bandwidth, which OAM mode, which polarization, or which radio frequency bandwidth to assign each signal to, based on information input from the outside, a preset value, statistical channel information, etc. Hereinafter, the determined information will be referred to as assignment information.

[0176] Then, the transmitting unit 120 of the transmitting device 100 transmits the assignment information to the receiving device 200 (step S102).

[0177] Subsequently, the transmitting unit 120 of the transmitting device 100 transmits the OAM signal (step S103). The receiving control unit 230 of the receiving device 200 processes the OAM signal based on the assignment information (step S104).

[0178] In addition, the transmission control unit 130 may, in step S101 described above, calculate the isolation between OAM modes and make an assignment that minimizes the isolation, or make an assignment that makes the isolation smaller than a predetermined reference value.

[0179] (Pattern 2) Pattern 2 is a closed-loop control pattern in which channel information and other data are fed back from the receiving control unit 230 to the transmitting control unit 130.

[0180] Figure 32 is a sequence diagram showing an example of the control process flow according to Pattern 2 of an embodiment of the present invention. The transmitting unit 120 of the transmitting device 100 transmits a known signal to the receiving device 200 (step S201). The known signal is a signal whose nature is known in advance to the receiving device 200, and may be a reference signal or any other signal.

[0181] The receiving control unit 230 of the receiving device 200 estimates the channel state based on known signals (step S202). For example, the receiving control unit 230 may estimate each OAM mode, bandwidth, radio frequency band, polarization channel, etc., based on known signals.

[0182] The receiving device 200 transmits channel information to the transmitting device 100 (step S203). The channel information includes information indicating the assumed OAM mode, bandwidth, radio frequency band, polarization channel, etc.

[0183] The transmission control unit 130 determines the signal assignment based on the channel information (step S204). For example, the transmission control unit 130 determines, based on the channel information, which bandwidth, which OAM mode, which polarization, or which radio frequency bandwidth to assign each signal to. Hereinafter, the determined information will be referred to as assignment information.

[0184] Then, the transmitting unit 120 of the transmitting device 100 transmits the assignment information to the receiving device 200 (step S205).

[0185] Subsequently, the transmitting unit 120 of the transmitting device 100 transmits the OAM signal (step S206). The receiving control unit 230 of the receiving device 200 processes the OAM signal based on the assignment information (step S207).

[0186] (Pattern 3) Pattern 3 is a limited-loop control pattern in which some of the information contained in channel information, etc., is fed back from the receiving control unit 230 to the transmitting control unit 130.

[0187] Figure 33 is a sequence diagram showing an example of the control process flow according to Pattern 3 of the embodiment of the present invention. The transmitting unit 120 of the transmitting device 100 transmits a known signal to the receiving device 200 (step S301).

[0188] The receiving control unit 230 of the receiving device 200 estimates the communication quality of the channel based on known signals (step S302).

[0189] The receiving device 200 transmits communication quality information to the transmitting device 100 (step S303). The communication quality information is an example of some of the information included in the channel information and indicates the communication quality of the channel. For example, the communication quality information may not be complete channel information, but may include only the received SNR (signal-to-noise ratio) or SINR (signal-to-interference-plus-noise ratio) for each OAM mode.

[0190] The transmission control unit 130 determines the signal assignment based on the communication quality information (step S304). For example, the transmission control unit 130 determines, based on the communication quality information, which bandwidth, which OAM mode, which polarization, or which radio frequency bandwidth to assign each signal to. Hereinafter, the determined information will be referred to as assignment information.

[0191] Then, the transmitting unit 120 of the transmitting device 100 transmits the assignment information to the receiving device 200 (step S305).

[0192] Subsequently, the transmitting unit 120 of the transmitting device 100 transmits the OAM signal (step S306). The receiving control unit 230 of the receiving device 200 processes the OAM signal based on the assignment information (step S307).

[0193] (Pattern 4) Pattern 4 is a receiver orientation control pattern in which signal assignment information is fed back from the receiver control unit 230 to the transmit control unit 130.

[0194] Figure 34 is a sequence diagram showing an example of the control process flow according to pattern 4 of the embodiment of the present invention. The transmitting unit 120 of the transmitting device 100 transmits a known signal to the receiving device 200 (step S401).

[0195] The receiving control unit 230 of the receiving device 200 determines a method for assigning transmission signals based on known signals (step S402). For example, the receiving control unit 230 may estimate each OAM mode, bandwidth, radio frequency band, polarization channel, etc., based on known signals, and determine the assignment method that the transmitting device 100 should perform.

[0196] The receiving device 200 transmits signal assignment information to the transmitting device 100 (step S403). The signal assignment information is information indicating the method of assigning the determined signals.

[0197] The transmission control unit 130 assigns signals based on the signal assignment information (step S404). For example, the transmission control unit 130 determines, based on the signal assignment information, which bandwidth, which OAM mode, which polarization, or which radio frequency bandwidth to assign each signal to.

[0198] Subsequently, the transmitting unit 120 of the transmitting device 100 transmits the OAM signal (step S405). The receiving control unit 230 of the receiving device 200 processes the OAM signal based on the assignment method it has determined (step S406).

[0199] (Summary of the embodiments) This specification includes, at least, the transmitting device, receiving device, transmitting control method, and receiving control method described in the following sections. (Section 1) Multiple frequency conversion circuits that convert multiple baseband signals modulated into analog signals, each having a bandwidth based on the processing capability of the baseband signals, so that they each include different radio frequency bands, The system comprises an OAM signal generation circuit that generates OAM signals assigned to different OAM modes from the analog signals that have been converted to include different radio frequency bands. Transmitter. (Section 2) The plurality of frequency conversion circuits convert the modulated analog signal into different radio frequency bands, The OAM signal generation circuit generates OAM signals to which the analog signals, converted to different radio frequency bands, are each assigned to different OAM modes. The transmitting device described in paragraph 1. (Section 3) The plurality of frequency conversion circuits convert the modulated analog signals so that they include the same radio frequency band as each other. The OAM signal generation circuit generates OAM signals to which the analog signals, converted to include the same radio frequency band, are assigned to different OAM modes. The transmitting device described in paragraph 1. (Section 4) The plurality of frequency conversion circuits convert the modulated analog signal by determining, according to the priority of the plurality of baseband signals, whether to use a radio frequency band different from other OAM modes or a radio frequency band that includes the same radio frequency band as other OAM modes. The transmitting device described in paragraph 3. (Section 5) The OAM signal generation circuit generates OAM multiplexed signals, each assigned to a different OAM mode, where the analog signals, which are converted to different radio frequency bands for each UCA included in the plurality of UCAs, are assigned to different OAM modes. The transmitting device described in paragraph 2. (Section 6) The OAM signal generation circuit generates OAM multiplexed signals, each assigned to a different OAM mode, from the analog signals that have been converted to include the same radio frequency band for each of the UCAs, which are assigned to multiple UCAs. The transmitting device described in paragraph 3. (Section 7) The system comprises a plurality of transmission circuits including the plurality of frequency conversion circuits and the OAM signal generation circuit, The plurality of transmitting circuits generate OAM signals with different polarizations among themselves. The transmitting device described in paragraph 1. (Section 8) The system comprises a plurality of transmission circuits including the plurality of frequency conversion circuits and the OAM signal generation circuit, The plurality of transmitting circuits generate OAM signals with different polarizations among themselves. A transmitting device as described in paragraph 5 or 6. (Section 9) The system comprises a plurality of transmission circuits including the plurality of frequency conversion circuits and the OAM signal generation circuit, The plurality of transmitting circuits generate OAM signals with different time slots among themselves. The transmitting device described in paragraph 1. (Section 10) A plurality of transmission circuits including the plurality of frequency conversion circuits and the OAM signal generation circuit, The system includes a signal synthesis circuit that synthesizes the OAM signals generated by the plurality of transmission circuits, The plurality of transmitting circuits generate OAM signals in different radio frequency bands among themselves. The transmitting device described in paragraph 1. (Section 11) A plurality of transmission circuits including the plurality of frequency conversion circuits and the OAM signal generation circuit, It comprises a signal synthesis circuit that synthesizes the generated OAM signals, The plurality of transmitting circuits each generate OAM signals assigned to different OAM modes, where the analog signals converted to radio frequency bands in adjacent radio frequency bands, with guard intervals provided between each transmitting circuit, generate OAM signals. The transmitting device described in paragraph 1. (Section 12) An OAM signal separation circuit separates analog signals containing different radio frequency bands from OAM signals assigned to different OAM modes. The system comprises multiple demodulation circuits that demodulate the separated OAM signal into multiple baseband signals having a bandwidth based on the processing capability of the baseband signal, Receiving device. (Section 13) The OAM signal separation circuit separates the OAM signals, which are each assigned to different OAM modes, from the analog signals that have been converted to different radio frequency bands. The receiving device described in item 12. (Section 14) The OAM signal separation circuit separates the OAM signals, each assigned to a different OAM mode, from the analog signals that have been converted to include the same radio frequency band. The receiving device described in item 12. (Section 15) The OAM signal separation circuit separates the OAM multiplexed signals, each assigned to a different OAM mode, from the analog signals that have been converted to different radio frequency bands for each of the UCAs included in the plurality of UCAs. The receiving device described in item 13. (Section 16) The OAM signal separation circuit separates the OAM multiplexed signals, each assigned to a different OAM mode, from the analog signals that have been converted to include the same radio frequency band for each of the UCAs, which are assigned to multiple UCAs. The receiving device described in paragraph 1, item 4. (Section 1 7) The system comprises a plurality of receiving circuits, including the plurality of demodulation circuits and the OAM signal separation circuit. The plurality of receiving circuits separate OAM signals with different polarizations from each other. The receiving device described in item 12. (Section 18) The system comprises a plurality of receiving circuits, including the plurality of demodulation circuits and the OAM signal separation circuit. The plurality of receiving circuits separate OAM signals with different polarizations from each other. A receiving device as described in paragraph 1, item 5 or 16. (Section 19) The system comprises a plurality of receiving circuits, including the plurality of demodulation circuits and the OAM signal separation circuit. The plurality of receiving circuits separate OAM signals of different time slots from each other. The receiving device described in item 12. (Section 20) Multiple receiving circuits including the multiple demodulation circuits and the OAM signal separation circuit, The system includes a signal separation circuit for separating the OAM signals separated by the plurality of receiving circuits, The plurality of receiving circuits generate OAM signals in different radio frequency bands among themselves. The receiving device described in item 12. (Section 21) Multiple receiving circuits including the multiple demodulation circuits and the OAM signal separation circuit, The system includes a signal separation circuit for separating the OAM signals separated by the plurality of receiving circuits, The plurality of receiving circuits separate the OAM signals, which have been converted to radio frequency bands adjacent to each other and with guard intervals provided between each receiving circuit, and which are assigned to different OAM modes. The receiving device described in item 12. (Section 22) A transmission control method performed by a transmitting device comprising: a plurality of frequency conversion circuits that each convert a plurality of baseband signals modulated from an analog signal having a bandwidth based on the processing capability of the baseband signal to include different radio frequency bands; and an OAM signal generation circuit that generates OAM signals in which the analog signals converted to include different radio frequency bands are each assigned to different OAM modes, the method being performed by the transmitting device The steps include assigning the plurality of baseband signals to different radio frequency bands, The system includes the step of transmitting information indicating the assigned result to a receiving device. Transmission control method. (Section 23) A receiving control method performed by a receiving device comprising: an OAM signal separation circuit that separates OAM signals, each assigned to a different OAM mode, from analog signals containing different radio frequency bands; and a plurality of demodulation circuits that demodulate the separated OAM signals into a plurality of baseband signals having a bandwidth based on the processing capability of the baseband signals, wherein the receiving device performs the receiving control method, The steps include receiving information from a transmitting device indicating the result of assigning the plurality of baseband signals to different radio frequency bands, The process includes the step of processing the OAM signal based on the received information, Reception control method.

[0200] Although this embodiment has been described above, the present invention is not limited to this specific embodiment, and various modifications and changes are possible within the scope of the gist of the present invention as described in the claims. [Explanation of symbols]

[0201] 100 Transmitter 110 Antenna 120 Transmitter 121 Modulation Circuit 122 Frequency conversion circuit 123 OAM signal generation circuit 124 Signal Synthesis Circuit 125 OAM signal generation circuit 130 Transmission Control Unit 200 Receiver 210 Antenna 220 Receiver 221 Demodulation Circuit 222 Frequency conversion circuit 223 OAM signal separation circuit 224 Signal separation circuit 225 OAM signal separation circuit 230 Receiving control unit

Claims

1. A transmitting device that transmits signals with a wider bandwidth than the said bandwidth by dividing the bandwidth according to the bandwidth based on the processing capability of the baseband signal, Multiple modulation circuits that modulate multiple baseband signals, each divided into bandwidths based on the processing capability of the baseband signal, into analog signals, Multiple frequency conversion circuits that convert multiple analog signals modulated by the multiple modulation circuits into a predetermined radio frequency band, The system includes an OAM signal generation circuit that generates OAM signals by assigning a plurality of analog signals converted to a predetermined radio frequency band to different OAM modes. Transmitter.

2. The transmitting device according to claim 1, wherein the plurality of frequency conversion circuits convert the plurality of analog signals modulated by the plurality of modulation circuits into different radio frequency bands.

3. The transmitting device according to claim 1, wherein the plurality of frequency conversion circuits convert the plurality of analog signals modulated by the plurality of modulation circuits so that they include the same radio frequency band.

4. The plurality of frequency conversion circuits convert the plurality of analog signals modulated by the plurality of modulation circuits by determining, according to the priority of the plurality of baseband signals, whether to use a radio frequency band different from other OAM modes or a radio frequency band that includes the same radio frequency band as other OAM modes. The transmitting device according to claim 1.

5. The OAM signal generation circuit generates an OAM multiplexed signal in which the multiple analog signals, each assigned to a UCA and converted to a different radio frequency band for each UCA, are assigned to a different OAM mode. The transmitting device according to claim 2.

6. The OAM signal generation circuit generates an OAM multiplexed signal in which the multiple analog signals, each assigned to a multiple UCA and converted to include the same radio frequency band for each UCA, are assigned to a different OAM mode. The transmitting device according to claim 3.

7. The system comprises a plurality of transmission circuits including the plurality of frequency conversion circuits and the OAM signal generation circuit, The plurality of transmitting circuits generate OAM signals with different polarizations among themselves. The transmitting device according to claim 1.

8. The system comprises a plurality of transmission circuits including the plurality of frequency conversion circuits and the OAM signal generation circuit, The plurality of transmitting circuits generate OAM signals with different polarizations among themselves. The transmitting device according to claim 5 or 6.

9. The system comprises a plurality of transmission circuits including the plurality of frequency conversion circuits and the OAM signal generation circuit, The plurality of transmitting circuits generate OAM signals with different time slots among themselves. The transmitting device according to claim 1.

10. A plurality of transmission circuits including the plurality of frequency conversion circuits and the OAM signal generation circuit, The system includes a signal synthesis circuit that synthesizes the OAM signals generated by the plurality of transmission circuits, The plurality of transmitting circuits generate OAM signals in different radio frequency bands among themselves. The transmitting device according to claim 1.

11. A plurality of transmission circuits including the plurality of frequency conversion circuits and the OAM signal generation circuit, It comprises a signal synthesis circuit that synthesizes the generated OAM signals, The plurality of transmitting circuits, having converted the plurality of analog signals into radio frequency bands that are adjacent to each other and have guard intervals between them, generate OAM signals that are assigned to different OAM modes. The transmitting device according to claim 1.

12. A receiving device that receives a signal transmitted by the transmitting device described in claim 1, An OAM signal separation circuit separates multiple analog signals converted to a predetermined radio frequency band into OAM signals assigned to different OAM modes, and each OAM mode signal is separated. The system comprises multiple demodulation circuits that demodulate the separated signals of each OAM mode into multiple baseband signals having a bandwidth based on the processing capability of the baseband signals, Receiving device.

13. The OAM signal separation circuit separates the OAM signals that have been converted to different radio frequency bands and are assigned to different OAM modes. The receiving device according to claim 12.

14. The OAM signal separation circuit separates the OAM signals, which are assigned to different OAM modes, from the multiple analog signals that have been converted to include the same radio frequency band. The receiving device according to claim 12.

15. The OAM signal separation circuit separates the OAM multiplexed signals, which are assigned to a plurality of UCAs and converted to different radio frequency bands for each UCA included in the plurality of UCAs, and which are assigned to different OAM modes. The receiving device according to claim 13.

16. The OAM signal separation circuit separates the OAM multiplexed signals, which are assigned to a plurality of UCAs and converted so that each UCA included in the plurality of UCAs includes the same radio frequency band, and which are assigned to different OAM modes. The receiving device according to claim 14.

17. The system comprises a plurality of receiving circuits, including the plurality of demodulation circuits and the OAM signal separation circuit. The plurality of receiving circuits separate OAM signals with different polarizations from each other. The receiving device according to claim 12.

18. The system comprises a plurality of receiving circuits, including the plurality of demodulation circuits and the OAM signal separation circuit. The plurality of receiving circuits separate OAM signals with different polarizations from each other. The receiving device according to claim 15 or 16.

19. The system comprises a plurality of receiving circuits, including the plurality of demodulation circuits and the OAM signal separation circuit. The plurality of receiving circuits separate OAM signals of different time slots from each other. The receiving device according to claim 12.

20. Multiple receiving circuits including the multiple demodulation circuits and the OAM signal separation circuit, The system includes a signal separation circuit for separating the OAM signals separated by the plurality of receiving circuits, The plurality of receiving circuits generate OAM signals in different radio frequency bands among themselves. The receiving device according to claim 12.

21. Multiple receiving circuits including the multiple demodulation circuits and the OAM signal separation circuit, The system includes a signal separation circuit for separating the OAM signals separated by the plurality of receiving circuits, The plurality of receiving circuits separate the OAM signals, which have been converted to radio frequency bands adjacent to each other and with guard intervals provided between each receiving circuit, and which are assigned to different OAM modes. The receiving device according to claim 12.

22. A transmitting device that transmits signals with a wider bandwidth than the given bandwidth by dividing the bandwidth according to the processing capability of the baseband signal, Multiple baseband signals, each with a bandwidth based on the processing capability of the baseband signal, are modulated into multiple analog signals. The modulated multiple analog signals are converted into a predetermined radio frequency band. Multiple analog signals converted to the predetermined radio frequency band are used to generate OAM signals assigned to different OAM modes. Assignment information indicating the assignment of each OAM mode to the OAM signal is transmitted to the receiving device. Transmission control method.

23. A receiving device that receives a signal transmitted by a transmitting device using the transmission control method described in claim 22, Based on the assignment information received from the transmitting device, Multiple analog signals converted to a predetermined radio frequency band are separated into signals for each OAM mode, with each OAM signal assigned to a different OAM mode. The separated signals of each OAM mode are demodulated into a plurality of baseband signals having a bandwidth based on the processing capability of the baseband signals. Reception control method.

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