Wireless communication system, communication method, and parameter control device

Abstract

Provided is a wireless communication system that executes OAM multiplex transmission, the system comprising: a parameter control unit that determines parameters for OAM modes in the OAM multiplex transmission, on the basis of the transmission characteristics of the OAM modes; and a transmission unit that executes the OAM multiplex transmission on the basis of the parameters determined by the parameter control unit.

Description

[Technical Field]

[0001] The present invention relates to parameter control of OAM multiplex transmission. [Background technology]

[0002] In recent years, spatial multiplexing transmission technology for wireless signals using OAM has been studied to improve communication capacity (for example, Non-Patent Document 1). Electromagnetic waves with OAM have equiphase planes distributed in a spiral pattern along the propagation direction, centered on the propagation axis. Electromagnetic waves with different OAM modes propagating in the same direction have orthogonal spatial phase distributions in the direction of the rotation axis. Therefore, signals can be spatially multiplexed by separating the signals of each OAM mode modulated with different signal sequences at the receiving device.

[0003] In a wireless communication system using this OAM multiplexing transmission technology, a uniform circular array (hereinafter referred to as UCA (Uniform Circular Array)) antenna, in which multiple antenna elements are arranged at equal intervals in a circle, is used to generate, combine, and transmit multiple OAM modes, thereby achieving spatially multiplexed transmission of different signal sequences (see, for example, Non-Patent Document 2). A Butler circuit (Butler matrix circuit), for example, is used to generate and separate signals for multiple OAM modes. [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] J.Wang et. al., "Terabit free-space data transmission employing orbital angular momentum multiplexing," Nature Photonics, vol.6, pp.488-496. ,July, 2012. [Non-patent document 2] Y.Yan et al., "High-capacity millimeter-wave communications with orbital angular momentum multiplexing," Nature Commun., vol.5, p.4876, Sep. 2014. Summary of the Invention [Problem to be solved by the invention]

[0005] OAM multiplexing transmission requires that the transmitting and receiving antennas be placed on the same axis, and misalignment of the antennas significantly degrades performance. This poses a significant operational hurdle. Specifically, misalignment of the antennas results in a degradation of throughput.

[0006] The present invention has been made in view of the above points, and has an object to provide a technique that makes it possible to reduce degradation in throughput in OAM multiplex transmission. [Means for solving the problem]

[0007] According to the disclosed technology, there is provided a wireless communication system that performs OAM multiplexing transmission, a parameter control unit that determines parameters for each OAM mode based on transmission characteristics of each OAM mode in the OAM multiplexed transmission; a transmission unit that performs the OAM multiplexing transmission based on the parameters determined by the parameter control unit, The parameter control unit determines, as the parameter, a modulation method or a transmission power for each OAM mode. A wireless communication system is provided. [Effects of the Invention]

[0008] According to the disclosed technology, a technology is provided that makes it possible to reduce throughput degradation in OAM multiplexed transmission. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a diagram illustrating an example of the overall configuration of a wireless communication system according to an embodiment of the present invention. [Figure 2] 10A and 10B are diagrams illustrating phase differences given to each antenna element in each mode. [Figure 3] FIG. 2 is a functional configuration diagram of a transmitting device 100. [Figure 4] FIG. 2 is a functional configuration diagram of a receiving device 200. [Figure 5] FIG. 2 is a functional configuration diagram of a parameter control unit 110. [Figure 6] FIG. 10 is a diagram showing the relationship between distance and received power for each OAM mode. [Figure 7] 10 is a flowchart for explaining the operation of the parameter control unit 110. [Figure 8] FIG. 10 is a diagram for explaining a method for determining a modulation scheme. [Figure 9] FIG. 2 is a functional configuration diagram of a parameter control unit 240. [Figure 10] 10 is a flowchart for explaining the operation of the parameter control unit 240. [Figure 11] FIG. 10 is a diagram for explaining a method of redistributing transmission power. [Figure 12] FIG. 10 is a configuration diagram of a modified example. [Figure 13] FIG. 2 illustrates an example of a hardware configuration of the apparatus. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of the present invention (the present embodiment) will be described with reference to the drawings. The embodiment described below is merely an example, and the embodiment to which the present invention is applied is not limited to the following embodiment.

[0011] (Example of overall system configuration) An example of the overall configuration of a wireless communication system according to an embodiment of the present invention is shown in Fig. 1. As shown in Fig. 1, the wireless communication system according to this embodiment includes a transmitting device 100 and a receiving device 200.

[0012] The transmitting device 100 has an OAM mode generation function and a UCA. The receiving device 200 has an OAM mode separation function and a UCA. The transmitting device 100 multiplexes signals of one or more OAM modes and transmits them from the UCA. The receiving device 200 receives the signals multiplexed with one or more OAM modes transmitted from the transmitting device 100 using the UCA and separates each OAM mode.

[0013] In this embodiment, it is assumed that the transmitting device 100 and the receiving device 200 are stationary base stations, respectively, but this assumption is merely an example.

[0014] (OAM multiplex transmission) Here, the basic processing contents of the OAM multiplexing transmission performed by the transmitting device 100 and the receiving device 200 will be explained.

[0015] The OAM mode signal in the transmitting device 100 is generated by applying a phase difference based on a DFT transformation matrix to the signal supplied to each antenna element of the UCA. Specifically, the OAM mode n signal is generated by setting the phase difference supplied to each antenna element so that the phase rotates by n.

[0016] Figure 2 shows the phase difference applied to each antenna element in each mode when generating OAM mode signals using an eight-element UCA. For example, when generating OAM mode 2 signals using an eight-element UCA, the phase differences applied to each antenna element are 0 degrees, 90 degrees, 180 degrees, 270 degrees, 0 degrees, 90 degrees, 180 degrees, and 270 degrees clockwise. The number of multiplexed modes can be up to the same number as the number of antenna elements (for example, if the number of antenna elements is eight, eight modes: modes 0, 1, -1, 2, -2, 3, -3, and 4 can be used), but fewer modes are also possible.

[0017] To separate the OAM multiplexed signal in the receiving device 200, the phase of each antenna element of the UCA on the receiving side may be set to rotate in the opposite direction to the phase of the transmitting device 100.

[0018] (Summary of the problem and the process to solve it) As mentioned above, OAM multiplexing transmission has the problem of throughput degradation due to misalignment of the transmitting and receiving antennas.

[0019] In order to solve the above problem, in this embodiment, the degradation of throughput caused by, for example, axis misalignment is reduced by controlling parameters such as ON / OFF of the OAM mode (which OAM mode to use) and transmission power.

[0020] Specifically, parameters for each OAM mode are determined based on the transmission characteristics (e.g., SNR (Signal-to-Noise Ratio)) of each OAM mode in OAM multiplexed transmission. In one embodiment, the transmitting device 100 transmits a known preamble for transmission and reception, and the receiving device 200 receives the preamble and estimates the transmission characteristics. The receiving device 200 determines parameters based on the estimation results and feeds back the determined parameters to the transmitting device 100.

[0021] The above processing enables adaptive control of L1 parameters (for example, physical layer parameters such as transmission power, modulation method, OAM mode, etc.) according to propagation characteristics and reception characteristics, thereby improving throughput.

[0022] The configuration and operation of the device for solving the above problems will be described in detail below.

[0023] (Device configuration example) 3 is a diagram showing an example of a functional configuration of the transmitting device 100 according to the present embodiment. As shown in FIG. 3, the transmitting device 100 includes a parameter control unit 110, a preamble generation unit 120, a data generation unit 130, a modulation unit 140, a power control unit 150, a mode multiplexing unit 160, and a UCA 170.

[0024] The parameter control unit 110, preamble generation unit 120, data generation unit 130, modulation unit 140, power control unit 150, and mode multiplexing unit 160 may all be realized by hardware circuits (digital circuits or analog circuits), or by running a program on a computer equipped with a CPU and memory.

[0025] Furthermore, the configuration including "the preamble generating unit 120, the data generating unit 130, the modulating unit 140, the power control unit 150, the mode multiplexing unit 160, and the UCA 170" may be called a transmitting unit.

[0026] The preamble generation unit 120 generates, as an orthogonal preamble for each OAM mode, a signal sequence, such as an M sequence, whose autocorrelation is ≠ 0 and whose cross-correlation is 0. The preamble is an example of a known signal.

[0027] The data generator 130 generates transmission data and inserts the generated data after the preamble. The modulator 140 modulates the preamble and data using a modulation method such as QAM (Quadrature Amplitude Modulation). The power controller 150 controls the transmission power of each OAM mode.

[0028] Parameter control section 110 notifies modulation section 140 of the modulation method and notifies transmission power to power control section 150. Modulation section 140 and power control section 150 each perform operations using the modulation method / transmission power notified by parameter control section 110.

[0029] The mode multiplexer 160 generates an OAM wave carrying the signal modulated by the modulator 140, and the UCA 170 transmits the OAM wave.

[0030] 4 is a diagram showing an example of the functional configuration of the receiving device 200. The receiving device 200 includes a UCA 210, a mode separation unit 220, a demodulation unit 230, and a parameter control unit 240.

[0031] The mode separation unit 220, demodulation unit 230, and parameter control unit 240 may all be realized by a hardware circuit (digital circuit or analog circuit), or may be realized by causing a computer equipped with a CPU and memory to execute a program.

[0032] UCA 210 receives a signal transmitted from transmitting device 100, mode separation section 220 separates the signal into each OAM mode, and demodulation section 230 demodulates the separated signals for each OAM mode. Parameter control section 240 determines parameters (e.g., ON / OFF, modulation method, or transmission power) for each OAM mode based on the demodulation results by demodulation section 230, and feeds back the determined parameters to transmitting device 100.

[0033] When the transmitting apparatus 100 receives feedback from the receiving apparatus 200, the transmitting apparatus 100 operates in accordance with the parameters of the feedback.

[0034] Hereinafter, detailed configurations and operations related to parameter control will be described as Example 1 and Example 2. In Example 1, the transmitting device 100 determines initial parameters and starts communication according to the parameters. In Example 2, the receiving device 200 determines parameters based on a preamble received from the transmitting device 100 and feeds back the determined parameters to the transmitting device 100.

[0035] Although it is assumed that Example 1 and Example 2 are implemented in combination, this is not limiting and each may be implemented independently. In other words, it is possible to "implement only Example 1 without implementing Example 2," or "implement only Example 2 without implementing Example 1."

[0036] Example 1 First, the first embodiment will be described.

[0037] <First embodiment: Example of configuration of parameter control unit 110> 5 is a diagram showing an example of the functional configuration of the parameter control unit 110 of the transmission device 100. The parameter control unit 110 determines the transmission power and modulation method at the time of initial connection between the transmission device 100 and the reception device 200.

[0038] The parameter control unit 110 of the transmitting device 100 includes a distance characteristic holding unit 111, a power calculation unit 112, a modulation method determination unit 113, and a modulation method holding unit 114. Note that the "power calculation unit 112 and the modulation method determination unit 113" may be collectively referred to as a parameter determination unit.

[0039] Distance characteristic storage unit 111 stores the relationship between distance and received power for each OAM mode in a discrete manner. An example of the relationship between distance and received power for each OAM mode is shown in Figure 6. This relationship is calculated in advance.

[0040] Distance characteristic storage unit 111 may store the "relationship between distance and received power for each OAM mode" as a table, as a mathematical formula expressing the relationship, or in some other format.

[0041] The "distance" (distance between the transmitting and receiving devices) shown in FIG. 6 is the distance between the transmitting device 100 (more specifically, UCA 170) and the receiving device 200 (more specifically, UCA 210). The "received power" is the received power at the receiving device 200 (more specifically, UCA 210). The received power is the received power when a certain transmission power is assumed to be used. In FIG. 6, the received power is the relative received power when the transmission power is 0 dB.

[0042] The relationship stored in distance characteristic storage unit 111 may be "the relationship between the distance and the received power for each OAM mode" as shown in FIG. 6, or may be "the relationship between the distance and the propagation loss for each OAM mode."

[0043] The power calculation unit 112 obtains the received power of each OAM mode between the transmitting and receiving devices based on the distance between the transmitting and receiving devices and the "relationship between the distance and the received power of each OAM mode" stored in the distance characteristic storage unit 111, and calculates the propagation loss P L (m), and calculate the received SNR, etc. Note that the propagation loss can basically be calculated by subtracting the received power from the transmitted power.

[0044] Propagation loss P L In (m), m is the index of the OAM mode. Here, the distance between the transmitter and receiver may be measured using a laser or the like, or a design value may be used.

[0045] The modulation scheme holding unit 114 holds the "relationship between the received SNR and the modulation scheme." The modulation scheme holding unit 114 may hold the "relationship between the received SNR and the modulation scheme" as a table, as a mathematical formula expressing the relationship, or in some other format. The modulation scheme determination unit 113 determines the modulation scheme from the received SNR based on the "relationship between the received SNR and the modulation scheme" held in the modulation scheme holding unit 114.

[0046] <Example 1: Example of operation of parameter control unit 110> Next, an example of the operation of the parameter control unit 110 will be described with reference to the flowchart of FIG.

[0047] In S101, the distance between the transmitting device 100 (more specifically, the UCA 170) and the receiving device 200 (more specifically, the UCA 210) is input to the power calculation unit 112 of the parameter control unit 110.

[0048] In S102, the power calculation unit 112 acquires the reception power of each OAM mode corresponding to the input distance from the distance characteristic storage 111. Here, the transmission power of each OAM mode is P tx (m).

[0049] In S103, the power calculation unit 112 distributes the transmission power equally to all OAM modes. tx (1)=P tx (2)=…=P tx (M)=P tot / M, where P tot is the total transmission power in the transmitting device 100, and M is the number of OAM modes.

[0050] In S104, the power calculation unit 112 calculates the reception SNR of each OAM mode according to the following formula:

[0051] SNR(m)=P tx (m)-P L (m)-N where P tx (m) is the transmission power of OAM mode m, and P L (m) is the propagation loss of the propagation path of OAM mode m. N is the noise power, and either the theoretical value of thermal noise calculated below using bandwidth B or a measured value can be used.

[0052] N=-174+10log 10 (B) In S105, the power calculation unit 112 determines whether the reception SNR is equal to or greater than the minimum reception SNR in all OAM modes. If the determination result is No (there is an OAM mode in which the reception SNR is less than the minimum reception SNR), the process proceeds to S106, and if the determination result is Yes (the reception SNR is equal to or greater than the minimum reception SNR in all OAM modes), the process proceeds to S107.

[0053] If the result of the determination is No, that is, if the reception SNR for a certain OAM mode is lower than the minimum reception SNR for the prepared modulation scheme, in S106, the power calculation unit 112 turns off the OAM mode. Here, the minimum reception SNR is, for example, 6.5 dB, which is the SNR that can be received with QPSK modulation without error correction.

[0054] In addition, in S106, parameter control unit 110 instructs preamble generation unit 120 to notify the transmitting device that transmission (generation) of preambles in the OAM mode in which the reception SNR is below the minimum reception SNR will be stopped. As a result, preamble transmission for the OAM mode is stopped.

[0055] After S106, the process returns to S103, where power calculation unit 112 equally allocates (redistributes) the transmission power to all OAM modes except for the OAM mode that has been turned off. That is, power calculation unit 112 redistributes the surplus transmission power resulting from turning off an OAM mode to other modes. For example, when OAM mode M is turned off, the transmission power is redistributed according to the following formula:

[0056] P tx (1)=P tx (2)=…=P tx (M-1)=P tot / (M-1) The power calculation unit 112 may use the water-filling theorem for the power distribution. As long as the determination in S105 is not Yes, S103 to S106 are repeatedly executed.

[0057] In S107, when the determination in S105 is Yes, the power calculation unit 112 determines the transmission power for each OAM mode. Here, a distribution coefficient for the transmission power is determined. For example, when the transmission power is equally distributed to all OAM modes except for the OAM mode that is turned OFF, if S105 is Yes with OAM mode M turned OFF, the distribution coefficient for the transmission power is 1 / (M-1). In other words, P tot / (M-1) is distributed among each OAM mode used.

[0058] In S108, the modulation scheme determination unit 113 determines a modulation scheme based on the reception SNR of each OAM mode that is not turned off. Specifically, the modulation scheme determination unit 113 makes the determination by referring to the "relationship between reception SNR and modulation scheme" stored in the modulation scheme storage unit 114.

[0059] More specifically, for each OAM mode, the maximum modulation scheme that allows error-free reception at a certain reception SNR is recorded in modulation scheme storage unit 114. For each OAM mode, modulation scheme storage unit 114 may also store the minimum reception SNR that allows error-free reception for each available modulation scheme.

[0060] For example, the height of each bar in Figure 8 represents the received SNR for each OAM mode. Each dashed line drawn horizontally in Figure 8 (corresponding to each modulation method) represents the minimum received SNR that can be received without errors for the corresponding modulation method. The received SNR may also be referred to as the "number of transmittable bits."

[0061] If modulation scheme determination unit 113 selects the maximum modulation scheme that can be received without error for each OAM mode, in the case of Fig. 8, modulation scheme determination unit 113 selects 256QAM for OAM mode 0, and 128QAM for modes 1 and -1. The same applies to the other OAM modes.

[0062] Note that the method of selecting (determining) the modulation scheme is not limited to the above method. For example, when there are multiple selectable modulation schemes, the modulation scheme determination unit 113 may select a modulation scheme that is N (N is a natural number) lower than the maximum modulation scheme that can be received without error. N is, for example, 1. In the case of Figure 8, if N is 1, the modulation scheme determination unit 113 selects 128QAM for OAM mode 0.

[0063] As described above, by determining a large (high level) modulation scheme based on the minimum received SNR, it is possible to determine a modulation scheme that increases throughput.

[0064] The transmission power determined for each OAM mode is notified from parameter control unit 110 to power control unit 150, and the modulation method determined for each OAM mode is notified from parameter control unit 110 to modulation unit 140, and each unit operates according to the parameters notified from parameter control unit 110.

[0065] Example 2 Next, a second embodiment will be described.

[0066] <Embodiment 2: Example of configuration of parameter control unit 110> 9 is a diagram illustrating an example of the functional configuration of the parameter control unit 240 of the receiving device 200. The parameter control unit 240 of the receiving device 200 includes a reception SNR estimating unit 241, an error detecting unit 242, a parameter determining unit 243, a modulation scheme holding unit 244, and a feedback unit 245.

[0067] The modulation scheme holding unit 244 holds the "relationship between the received SNR and the modulation scheme." The modulation scheme holding unit 244 may hold the "relationship between the received SNR and the modulation scheme" as a table, as a mathematical formula expressing the relationship, or in any other format.

[0068] The reception SNR estimation unit 241 estimates the reception SNR for each OAM mode using the preamble received from the transmitting device 100. The error detection unit 242 detects errors in the signal received from the transmitting device 100. The parameter determination unit 243 determines parameters such as the modulation method, OAM mode ON / OFF, and transmission power. The feedback unit 245 transmits (feeds back) the parameters determined by the parameter determination unit 243 to the transmitting device 100.

[0069] <Example 2: Example of operation of parameter control unit 240> An example of the operation of the parameter control unit 240 will be described with reference to the flowchart of FIG.

[0070] Here, it is assumed that in all OAM modes, transmitting device 100 transmits a preamble (e.g., M sequence) that is orthogonal between OAM modes after modulation such as QAM, and receiving device 200 receives the preamble. For OAM modes that are OFF, only the preamble is transmitted. For OAM modes that are ON, the preamble and data are transmitted.

[0071] Furthermore, it is assumed that time is divided into frames (which may be called slots) of a certain time width, and the flow in Fig. 10 is executed for each frame. However, it is not limited to this assumption, and for example, the flow in Fig. 10 may be executed at time intervals other than frames, or at intervals of any number of frames.

[0072] In S201, the receiving device 200 performs OAM reception processing of the received signal. The preambles separated for each OAM mode are passed to the parameter control unit 240.

[0073] In S202, the reception SNR estimation unit 241 estimates the reception SNR for each OAM mode from the preamble. The reception SNR estimation unit 241 calculates the SNR from the difference between the known signal point of the preamble and the received signal point. For example, if the QAM-modulated transmission preamble is x(n) and the received preamble is y(n), the reception SNR estimation unit 241 calculates the reception SNR using the following formula:

[0074]

number

[0075] In S205, when an error occurs in a certain OAM mode, parameter determination unit 243 changes the modulation scheme for the OAM mode in which the error occurred to a modulation scheme that is one step lower than the current modulation scheme. Note that the method for changing the modulation scheme when an error occurs is not limited to changing to a modulation scheme that is one step lower than the current modulation scheme. For example, if the current modulation scheme is two or more steps higher than the lowest modulation scheme, the modulation scheme may be N steps lower (N is an integer greater than or equal to 2) than the current modulation scheme.

[0076] If an error occurs in the OAM mode of the lowest modulation method, in S205, the parameter determination unit 243 determines to turn off the OAM mode.

[0077] In both cases where no error has occurred (No in S204) and where the modulation method or the like has been switched (S205), the parameter determination unit 243 redistributes the transmission power in S206. In addition, in S206, the modulation method may be changed in conjunction with the redistribution of the transmission power.

[0078] Here, the modulation scheme storage unit 244 stores, for each OAM mode, the maximum modulation scheme that can be received without error at a certain reception SNR, similar to the modulation scheme storage unit 114 of the first embodiment. The modulation scheme storage unit 244 may store, for each OAM mode, the minimum reception SNR that can be received without error for each available modulation scheme.

[0079] The parameter determination unit 243 redistributes the transmission power based on the estimated reception SNR and the information stored in the modulation scheme storage unit 244. A specific example will be described with reference to Figs.

[0080] In Figure 11, (a) shows the state before the redistribution of transmit power, and (b) shows the state after the redistribution of transmit power. In both (a) and (b), as in Figure 8, the height of each bar indicates the estimated received SNR for each OAM mode, and each dashed line (corresponding to each modulation method) indicates the minimum received SNR (threshold) that can be received without errors for the corresponding modulation method.

[0081] 11(a) for OAM mode 0, the estimated reception SNR exceeds the minimum reception SNR of the modulation scheme (256QAN) used by α. In this case, parameter determination unit 243 distributes the excess transmission power equivalent to α to another OAM mode and raises the modulation scheme of that other OAM mode by one step.

[0082] 11(b), the transmission power corresponding to α from OAM mode 0 is distributed to OAM mode 1 and OAM mode-1, causing the estimated reception SNRs of OAM mode 1 and OAM mode-1 to increase by β and γ, respectively. As a result, the estimated reception SNRs of OAM mode 1 and OAM mode-1 have become the minimum reception SNRs possible for error-free reception in the modulation scheme one step higher (256QAM) than the modulation scheme before distribution (128QAM), so parameter determination unit 243 changes the modulation scheme of OAM mode 1 and OAM mode-1 from 128QAM to 256QAM.

[0083] In other words, in the above example, by distributing the surplus power α of OAM mode 0 to OAM modes 1 and -1 by β and γ respectively, the modulation method of OAM modes 1 and -1 is increased to 256QAM. In this case, α > β + γ. By increasing the modulation method, throughput can be improved.

[0084] The modulation method change and transmission power distribution in S205 and S206 above may be performed in only one of the positive and negative modes of the same order, taking advantage of the symmetry of the OAM modes, and the result of the change / distribution may be applied directly to the other mode.

[0085] For example, parameter determination section 243 determines the parameters based on the error detection flag for only the positive OAM mode or only the negative OAM mode in positive and negative OAM modes of the same order.

[0086] 10, the feedback unit 245 feeds back the parameters (modulation method, OAM mode OFF, transmission power, etc.) determined by the parameter determination unit 243 to the transmitting device 100. The transmitting device 100 applies the fed back parameters from the next frame.

[0087] Regarding the transmission power of each OAM mode, a distribution coefficient (the ratio of the transmission power of each OAM mode to the total transmission power) may be fed back, or the transmission power may be fed back.

[0088] Furthermore, for an OAM mode that is OFF, parameter control unit 240 may instruct transmitting device 100 to turn the OAM mode ON, for example, at predetermined time intervals. According to the flow of the second embodiment described above, if the reception SNR of the ON OAM mode is equal to or less than the threshold, the OAM mode is turned OFF again, and if the reception SNR exceeds the threshold, the OAM mode remains ON.

[0089] (Variation) Parameter control unit 110 in transmitting device 100 shown in Fig. 3 may be provided outside transmitting device 100. Similarly, parameter control unit 240 in receiving device 200 shown in Fig. 4 may be provided outside transmitting device 100. Parameter control unit 110 / 240 provided externally may be called a parameter control device.

[0090] 12 shows an example of a wireless communication system in which a parameter control device 300 is provided external to a transmitting device 100 and a receiving device 200. The parameter control device 300 executes the processes described in the first or second embodiment by communicating with the transmitting device 100 and the receiving device 200 via a network 400. The network 400 may be a small-scale network such as a LAN or an interface line between devices, or may be a wide-area network such as the Internet, a dedicated line, or a VPN.

[0091] The parameter control device 300 of FIG. 12 may include the functional unit of the parameter control unit 110 of the first embodiment (FIG. 5), the functional unit of the parameter control unit 240 of the second embodiment (FIG. 9), or both the functional unit of the parameter control unit 110 (FIG. 5) and the functional unit of the parameter control unit 240 (FIG. 9).

[0092] Note that either parameter control unit 110 provided inside transmitting device 100 or parameter control unit 240 provided inside receiving device 200 may be referred to as a parameter control device.

[0093] In addition, both the "parameter control device including the functions of parameter control unit 110" provided outside the transmitting device 100 and the "parameter control device including the functions of parameter control unit 240" provided outside the receiving device 200 may be referred to as the parameter control unit.

[0094] (Example of hardware configuration) The parameter control device described in this embodiment can be realized, for example, by causing a computer to execute a program. This computer may be a physical computer or a virtual machine on the cloud.

[0095] That is, the parameter control device can be realized by executing a program corresponding to the processing performed by the parameter control device using hardware resources such as a CPU and memory built into a computer. The program can be recorded on a computer-readable recording medium (such as a portable memory) and stored or distributed. The program can also be provided via a network such as the Internet or email.

[0096] Fig. 13 is a diagram showing an example of the hardware configuration of the computer. The computer in Fig. 13 includes a drive device 1000, an auxiliary storage device 1002, a memory device 1003, a CPU 1004, an interface device 1005, a display device 1006, an input device 1007, an output device 1008, and the like, all of which are interconnected by a bus BS. The computer may further include a GPU.

[0097] A program for realizing processing on the computer is provided by a recording medium 1001 such as a CD-ROM or a memory card. When the recording medium 1001 storing the program is set in the drive device 1000, the program is installed from the recording medium 1001 to the auxiliary storage device 1002 via the drive device 1000. However, the program does not necessarily have to be installed from the recording medium 1001, but may be downloaded from another computer via a network. The auxiliary storage device 1002 stores the installed program as well as necessary files, data, etc.

[0098] The memory device 1003 reads and stores the program from the auxiliary storage device 1002 when an instruction to start the program is received. The CPU 1004 realizes functions related to the parameter control device in accordance with the program stored in the memory device 1003. The interface device 1005 is used as an interface for connecting to a network, etc. The display device 1006 displays a GUI (Graphical User Interface) or the like according to the program. The input device 1007 is composed of a keyboard, mouse, buttons, a touch panel, etc., and is used to input various operation instructions. The output device 1008 outputs the calculation results.

[0099] (Summary of implementation form, effects, etc.) As described above, the technology described in this embodiment enables adaptive control of parameters (e.g., physical layer parameters such as transmission power, modulation method, and OAM mode) according to the transmission characteristics of OAM multiplexed transmission, thereby improving throughput.

[0100] The following additional notes are provided regarding the above-described embodiments.

[0101] <Additional Notes> (Additional note 1) A wireless communication system that performs OAM multiplexing transmission, a parameter control unit that determines parameters for each OAM mode based on transmission characteristics of each OAM mode in the OAM multiplexed transmission; a transmission unit that performs the OAM multiplexing transmission based on the parameters determined by the parameter control unit; A wireless communication system comprising: (Additional note 2) The parameter control unit determines, as the parameter, ON / OFF, modulation method, or transmission power for each OAM mode. Item 1. A wireless communication system according to claim 1. (Additional note 3) The parameter control unit An OAM mode to be used for initial communication, and a transmission power and modulation method for each OAM mode to be used are determined based on transmission characteristics in each OAM mode according to the distance between the transmitter and a receiver that performs OAM multiplex communication with the transmitter. Item 3. A wireless communication system according to claim 2. (Additional note 4) The parameter control unit The parameter is determined based on an error detection flag of each OAM mode at the receiving side in the OAM multiplex transmission. 4. A wireless communication system according to any one of claims 1 to 3. (Additional note 5) The parameter control unit The parameter is determined based on an error detection flag of only the positive OAM mode or only the negative OAM mode among the positive and negative OAM modes of the same order in the OAM multiplex transmission. 5. A wireless communication system according to claim 4. (Additional note 6) A communication method executed in a wireless communication system that performs OAM multiplexing transmission, a parameter control step of determining parameters for each OAM mode based on transmission characteristics of each OAM mode in the OAM multiplexed transmission; a transmitting step of performing the OAM multiplexed transmission based on the parameters determined in the parameter control step; A communication method comprising: (Additional note 7) A parameter control device that determines parameters to be used in a transmitter in a wireless communication system that performs OAM multiplexing transmission, a parameter determination unit that determines parameters for each OAM mode based on transmission characteristics of each OAM mode in the OAM multiplexed transmission; A parameter control device comprising: (Additional note 8) The parameter determination unit determines, as the parameter, ON / OFF, modulation method, or transmission power for each OAM mode. Item 8. The parameter control device according to item 7.

[0102] Although the present embodiment has been described above, the present invention is not limited to such a specific embodiment, and various modifications and changes are possible within the scope of the gist of the present invention described in the claims. [Explanation of symbols]

[0103] 100 Transmitting device 110 Parameter control section 111 Distance characteristic holding section 112 Power calculation section 113 Modulation method determination unit 114 Modulation method holding section 120 Preamble generator 130 Data Generation Unit 140 Modulation section 150 Power control section 160 Mode multiplexing section 170 UCA 200 receiving device 210 UCA 220 Mode Separation Section 230 Demodulation section 240 Parameter control section 241 Received SNR Estimation Unit 242 Error detection unit 243 Parameter Determination Unit 244 Modulation method holding section 245 Feedback Section 300 Parameter Control Device 400 Network 1000 Drive Device 1001 Recording media 1002 Auxiliary storage 1003 Memory device 1004 CPU 1005 Interface device 1006 Display device 1007 Input Device 1008 Output Device

Claims

1. A wireless communication system that performs OAM multiplex transmission, a parameter control unit that determines parameters for each OAM mode based on transmission characteristics of each OAM mode in the OAM multiplex transmission; a transmission unit that performs the OAM multiplex transmission based on the parameters determined by the parameter control unit, The parameter control unit determines, as the parameter, a modulation method or a transmission power for each OAM mode. Wireless communication system.

2. A wireless communication system that performs OAM multiplex transmission, a parameter control unit that determines parameters for each OAM mode based on transmission characteristics of each OAM mode in the OAM multiplex transmission; a transmission unit that performs the OAM multiplex transmission based on the parameters determined by the parameter control unit, the parameter control unit is a wireless communication system that determines, as the parameters, ON / OFF, modulation method, or transmission power for each OAM mode, The parameter control unit Based on the transmission characteristics in each OAM mode according to the distance between the transmitter and a receiver that performs OAM multiplex communication with the transmitter, an OAM mode to be used for initial communication and a transmission power and modulation method for each OAM mode to be used are determined. Wireless communication system.

3. The parameter control unit The parameter is determined based on an error detection flag of each OAM mode at the receiving side in the OAM multiplex transmission.

3. The wireless communication system according to claim 1 or 2.

4. A wireless communication system that performs OAM multiplex transmission, a parameter control unit that determines parameters for each OAM mode based on transmission characteristics of each OAM mode in the OAM multiplex transmission; a transmission unit that performs the OAM multiplex transmission based on the parameters determined by the parameter control unit, The parameter control unit a wireless communication system in which the parameters are determined based on an error detection flag of each OAM mode at a receiving side in the OAM multiplex transmission; The parameter control unit The parameter is determined based on an error detection flag of only the positive OAM mode or only the negative OAM mode in the positive and negative OAM modes of the same order in the OAM multiplex transmission. Wireless communication system.

5. A communication method executed in a wireless communication system performing OAM multiplex transmission, comprising: a parameter control step of determining parameters for each OAM mode based on transmission characteristics of each OAM mode in the OAM multiplex transmission; a transmission step of performing the OAM multiplex transmission based on the parameters determined in the parameter control step, In the parameter control step, the wireless communication system determines a modulation method or a transmission power for each OAM mode as the parameter. Communication method.

6. A parameter control device that determines parameters to be used in a transmitter in a wireless communication system that performs OAM multiplex transmission, a parameter determination unit that determines parameters for each OAM mode based on transmission characteristics of each OAM mode in the OAM multiplex transmission; The parameter determination unit determines a modulation method or a transmission power for each OAM mode as the parameter. Parameter control device.

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