Transmitting device, control circuit, storage medium, and transmitting method

Abstract

To provide a transmission apparatus capable of improving total radiation power which is the sum of radiation power of each of a plurality of beams when the beams are formed.SOLUTION: A transmission apparatus includes: a plurality of antenna elements 1-1 to 1-N capable of forming one beam using two or more antenna elements and emitting multiple beams; a plurality of amplifiers 3-1 to 3-N; a storage unit 6 which stores a beam-forming excitation coefficient which is an excitation coefficient; an inter-beam weight calculation unit 7 which calculates, based on the beam-forming excitation coefficient, an inter-beam weight so that the total radiation power may be maximum; an excitation coefficient calculation unit 8 which calculates an excitation coefficient after update, on the basis of the beam-forming excitation coefficient and the inter-beam weight; and a plurality of DBF units 9-1 to 9-M which are the same in number as the beams, to generate a signal that is the base of beams emitted from the antenna elements, the beams being obtained when each of the units uses the excitation coefficient after update for one of the beams through the antenna elements.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a transmitting device, a control circuit, a storage medium, and a transmitting method capable of forming multiple beams. [Background technology]

[0002] Conventionally, array-fed reflector antennas have been used as satellite-mounted antennas for multi-beam satellite communications. Array-fed reflector antennas can form multiple beams using multiple antenna elements, but the antenna elements that form the beams are sometimes shared between different beams. In the case of a downlink transmitting antenna, each antenna element is provided with its own amplifier, and the amplifier's output power is subject to constraints. For shared elements, which are antenna elements shared between different beams, the total power of each beam must satisfy the amplifier's output power constraints. In addition, the excitation coefficient, which is the power ratio of each antenna element, is determined for each beam in accordance with the desired beam shape.

[0003] For example, Patent Document 1 discloses a technique for calculating an excitation coefficient in a defocused phased array-fed reflector antenna by repeatedly adjusting the excitation amplitude and phase so that the gain within the coverage area is equal to or greater than a specified value and the gain outside the coverage area is equal to or less than a specified value. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-124855 Summary of the Invention [Problem to be solved by the invention]

[0005] However, while the above-mentioned conventional techniques disclose a method for forming multiple beams using multiple antenna elements, they do not take into consideration the total radiated power of the defocused phased array-fed reflector antenna. As a result, even if the calculated excitation coefficient is used, the defocused phased array-fed reflector antenna may not be able to transmit efficiently, i.e., it may not be able to demonstrate its intended performance.

[0006] The present disclosure has been made in view of the above, and has an object to provide a transmitting device that can improve the total radiated power, which is the sum of the radiated powers of the beams when a plurality of beams are formed. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems and achieve the object, the present disclosure provides a method for generating a plurality of beams. at the same time The transmitter is characterized by comprising: a plurality of antenna elements capable of forming one beam using two or more antenna elements and radiating a plurality of beams; a plurality of amplifiers, each connected to a different one of the plurality of antenna elements; a storage unit for storing beamforming excitation coefficients, which are excitation coefficients for forming the beam; an inter-beam weight calculation unit for calculating inter-beam weights indicating a power ratio between the plurality of beams based on the beamforming excitation coefficients so as to maximize the total radiated power of the plurality of beams radiated from the transmitter; an excitation coefficient calculation unit for calculating updated excitation coefficients based on the beamforming excitation coefficients and the inter-beam weights; and a plurality of digital beamforming units, the same number as the plurality of beams, for generating signals that serve as the basis of the beams radiated from each antenna element when radiating using the plurality of antenna elements, using the updated excitation coefficient for one of the plurality of beams. [Effects of the Invention]

[0008] The transmitting device according to the present disclosure has an advantage of being able to improve the total radiated power, which is the sum of the radiated power of each beam when forming a plurality of beams. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a first diagram showing an example of the configuration of a satellite transmitter according to a first embodiment; [Figure 2] FIG. 2 is a second diagram showing an example of the configuration of a satellite transmitter according to the first embodiment; [Figure 3] FIG. 10 is a diagram showing an example of the range of antenna elements used in two beams among the antenna elements provided in the satellite transmitter according to the first embodiment; [Figure 4] FIG. 4 is a diagram showing an example of a footprint on the ground of a radiation pattern when a satellite transmitter according to the first embodiment radiates a beam using the antenna element shown in FIG. 3; [Figure 5] Flowchart showing the operation of the satellite transmitter according to the first embodiment [Figure 6] FIG. 1 is a diagram showing an example of the configuration of a processing circuit in a satellite transmitter according to a first embodiment when the processing circuit is realized by a processor and a memory; [Figure 7] FIG. 1 is a diagram showing an example of the configuration of a processing circuit in a satellite transmitter according to a first embodiment when the processing circuit is configured with dedicated hardware; [Figure 8] FIG. 10 is a diagram showing an example of an excitation coefficient table stored in a storage unit of a satellite transmitter according to a second embodiment. [Figure 9] FIG. 10 is a diagram showing an example of a calculation formula for the total radiated power of each antenna element when an inter-beam weight calculation unit of a satellite transmitter according to a second embodiment calculates an inter-beam weight and an example of power used by each beam. [Figure 10] FIG. 1 is a first diagram showing a specific example of an excitation coefficient table stored in a storage unit of a satellite transmitter according to a second embodiment; [Figure 11] FIG. 1 is a first diagram showing a specific example of beamforming excitation coefficients updated by an excitation coefficient calculation unit by multiplying beamforming excitation coefficients stored in a storage unit by inter-beam weights calculated by an inter-beam weight calculation unit in a satellite transmitter according to embodiment 2. [Figure 12] FIG. 2 is a second diagram showing a specific example of an excitation coefficient table stored in the storage unit of the satellite transmitter according to the second embodiment; [Figure 13]FIG. 2 is a second diagram showing a specific example of excitation coefficients for beamforming updated by the excitation coefficient calculation unit by multiplying the excitation coefficients for beamforming stored in the storage unit by the inter-beam weight calculated by the inter-beam weight calculation unit in the satellite transmitter according to the second embodiment. [Figure 14] FIG. 10 is a diagram showing an example in which constraints on the total radiation power for each antenna element in a satellite transmitter according to the third embodiment are expressed as equations. [Figure 15] FIG. 10 is a diagram showing an example in which constraint conditions on the total radiated power for each antenna element are expressed as equations when there is a minimum power constraint on the allocated power in a satellite transmitter according to a fourth embodiment. [Figure 16] FIG. 11 is a diagram showing a specific example of an excitation coefficient table stored in a storage unit of a satellite transmitter according to a fourth embodiment. [Figure 17] FIG. 1 is a first diagram showing a specific example of excitation coefficients for beamforming updated by an excitation coefficient calculation unit by multiplying the excitation coefficients for beamforming stored in a storage unit by the inter-beam weight calculated by an inter-beam weight calculation unit in a satellite transmitter according to embodiment 4. [Figure 18] FIG. 2 is a second diagram showing a specific example of excitation coefficients for beamforming updated by the excitation coefficient calculation unit by multiplying the excitation coefficients for beamforming stored in the storage unit by the inter-beam weight calculated by the inter-beam weight calculation unit in the satellite transmitter according to the fourth embodiment. [Figure 19] FIG. 13 is a diagram showing an example in which constraint conditions on the total radiated power for each antenna element are expressed as equations when there is a maximum power constraint on the allocated power in a satellite transmitter according to the fifth embodiment. [Figure 20] FIG. 10 shows a specific example of excitation coefficients for beamforming updated by an excitation coefficient calculation unit by multiplying the excitation coefficients for beamforming stored in a storage unit by the inter-beam weight calculated by an inter-beam weight calculation unit in a satellite transmitter according to a fifth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] A transmitting device, a control circuit, a storage medium, and a transmitting method according to embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings.

[0011] Embodiment 1 FIG. 1 is a first diagram showing a configuration example of a satellite transmitter 50 according to the first embodiment. In FIG. 1, satellite transmitter 50 includes antenna elements 1-1 to 1-N, amplifiers 3-1 to 3-N, DACs (Digital Analog Converters) 4-1 to 4-N, multiplexers 5-1 to 5-N, a memory unit 6, an inter-beam weight calculator 7, an excitation coefficient calculator 8, DBF (Digital Beam Forming) units 9-1 to 9-M, a communication request generator 13, and a reflector unit 15. In satellite transmitter 50 shown in FIG. 1, antenna elements 1-1 to 1-N form an array feed unit 14. FIG. 2 is a second diagram showing a configuration example of satellite transmitter 50 according to the first embodiment. In FIG. 2, satellite transmitter 50 includes antenna elements 1-1 to 1-N, amplifiers 3-1 to 3-N, DACs 4-1 to 4-N, multiplexing units 5-1 to 5-N, a memory unit 6, an inter-beam weight calculation unit 7, an excitation coefficient calculation unit 8, DBF units 9-1 to 9-M, and a communication request generation unit 13.

[0012] In the following description, antenna elements 1-1 to 1-N will be referred to as antenna element 1 when not distinguished, amplifiers 3-1 to 3-N will be referred to as amplifier 3 when not distinguished, DACs 4-1 to 4-N will be referred to as DAC 4 when not distinguished, multiplexers 5-1 to 5-N will be referred to as multiplexer 5 when not distinguished, and DBF units 9-1 to 9-M will be referred to as DBF unit 9 when not distinguished. Each DBF unit 9 includes a distributor 10 and excitation coefficient multipliers 12-1 to 12-N. In the following description, excitation coefficient multipliers 12-1 to 12-N will be referred to as excitation coefficient multiplier 12 when not distinguished. Furthermore, beams 2-1 to 2-M shown in FIGS. 1 and 2 will be referred to as beam 2 when not distinguished, and beam input signals 11-1 to 11-M will be referred to as beam input signal 11 when not distinguished. It should be noted that N is the number of antenna elements 1 provided in the satellite transmitter 50, and M is the number of beams 2 emitted from the satellite transmitter 50.

[0013] The satellite transmitter 50 is a transmitting device capable of emitting multiple beams 2. The satellite transmitter 50 performs satellite communication using beams 2-1 to 2-M, i.e., multiple beams. The satellite transmitter 50 may use an array-fed reflector antenna 40, as shown in FIG. 1, as an onboard antenna for satellite communication using multiple beams. The array-fed reflector antenna 40 includes an array feed unit 14 and a reflector unit 15. In the satellite transmitter 50, the excitation amplitude and phase of each antenna element 1, i.e., the excitation coefficient, are determined so that radio waves radiated from each antenna element 1 of the array feed unit 14 form a beam 2 of a desired shape at a specified point on the ground. The satellite transmitter 50 can simultaneously radiate multiple beams 2 using multiple antenna elements 1. The satellite transmitter 50 has a different excitation coefficient for each beam 2, allowing multiple antenna elements 1 to be shared when radiating multiple beams 2.

[0014] 3 is a diagram showing an example of the ranges of antenna elements 1 used for two beams 2 among the antenna elements 1 included in satellite transmitter 50 according to the first embodiment. In satellite transmitter 50, for example, as shown in FIG. 3, among the antenna elements 1 arranged in array feeder 14, the range of antenna elements 1 used for beam 2-1 overlaps with the range of antenna elements 1 used for beam 2-2. In FIG. 3, element range 16 is the range of antenna elements 1 that form beam 2-1, element range 17 is the range of antenna elements 1 that form beam 2-2, and element range 18 is the range of antenna elements 1 that are shared elements that form beams 2-1 and 2-2. In this way, satellite transmitter 50 can share some antenna elements 1 when forming multiple beams 2.

[0015] Fig. 4 is a diagram showing an example of the footprint on the ground of the radiation pattern when satellite transmitter 50 according to the first embodiment radiates beams 2-1 and 2-2 using antenna element 1 shown in Fig. 3. In Fig. 4, the circle shown by the dotted line is element beam 19, which is the footprint on the ground corresponding to one antenna element 1 of array feed unit 14. The radiation pattern described above is formed by combining element beams 19 shown by the dotted line, i.e., the footprints on the ground. Element beam 19 in the range where beam 2-1 and beam 2-2 overlap corresponds to antenna element 1 in element range 18 shown in Fig. 3.

[0016] In this embodiment, the satellite transmitter 50 will be described assuming that it is equipped with an array-fed reflector antenna 40 as shown in Fig. 1, but other types of communication devices may be used, such as a direct radiating array antenna as shown in Fig. 2, as long as they are made up of multiple antenna elements 1 and include an antenna capable of simultaneously forming multiple beams 2. Furthermore, although this embodiment will be described assuming that it is an antenna mounted on a satellite, such as the satellite transmitter 50 shown in Figs. 1 and 2, it can also be applied to communication systems at earth stations.

[0017] The configuration of the satellite transmitter 50 will be described.

[0018] The memory unit 6 stores beam forming excitation coefficients, which are excitation coefficients that indicate the power ratio of the radiated power for each antenna element 1 for each beam 2, so that the satellite transmitter 50 can form a beam 2 using multiple antenna elements 1.

[0019] The communication request generator 13 generates a communication request, which is a request for a beam 2 or the like emitted from the satellite transmitter 50. The communication request imposes restrictions such as an upper limit and a lower limit on the radiation power for a certain beam 2, for example. Note that the communication request generator 13 may generate the communication request inside the satellite transmitter 50 as shown in FIG. 1 or the like, or may generate the communication request outside the satellite transmitter 50. In the latter case, the satellite transmitter 50 acquires the communication request from outside the satellite transmitter 50.

[0020] The inter-beam weight calculation unit 7 calculates inter-beam weights indicating the power ratios of the multiple beams 2 formed and radiated by the satellite transmitter 50, i.e., the power ratios between the beams 2, based on the beam forming excitation coefficients stored in the storage unit 6 and the communication request generated by the communication request generation unit 13. Note that when there is no communication request, the inter-beam weight calculation unit 7 may calculate the inter-beam weights using only the beam forming excitation coefficients. The inter-beam weight calculation unit 7 calculates inter-beam weights indicating the power ratios between the multiple beams 2, based on the beam forming excitation coefficients, so that the total radiated power P of the multiple beams 2 radiated from the satellite transmitter 50 is maximized.

[0021] The excitation coefficient calculation unit 8 calculates updated excitation coefficients for each beam 2 based on the beam forming excitation coefficients stored in the storage unit 6 and the inter-beam weights calculated by the inter-beam weight calculation unit 7, i.e., updates the beam forming excitation coefficients for each beam 2. Note that in the examples of FIGS. 1 and 2, for simplicity's sake, the excitation coefficient calculation unit 8 outputs updated excitation coefficients only to DBF unit 9-1, but in reality it outputs updated excitation coefficients also to DBF units 9-2 to 9-M, i.e., to all DBF units 9. The excitation coefficient calculation unit 8 calculates N×M updated excitation coefficients, where N is the number of antenna elements 1 included in the satellite transmitter 50 and M is the number of beams 2 formed by the satellite transmitter 50.

[0022] Each of the multiple DBF units 9 distributes one input beam input signal 11 to the number of antenna elements 1, i.e., N, and multiplies each distributed beam input signal 11 by an updated excitation coefficient calculated by the excitation coefficient calculation unit 8. In the satellite transmitter 50, the number of DBF units 9 is the same as the number of beams 2 that can be formed by the satellite transmitter 50. In other words, the multiple DBF units 9, the same number as the multiple beams 2, each use an updated excitation coefficient for one of the multiple beams 2 to generate a signal that serves as the basis for the beam 2 radiated from each antenna element 1 when radiation is performed using the multiple antenna elements 1. In the following description, the DBF unit 9 may be referred to as a digital beam forming unit.

[0023] The distribution unit 10 distributes one beam input signal 11 input to the DBF unit 9 into the number of antenna elements 1, that is, N.

[0024] In the DBF unit 9, the plurality of excitation coefficient multipliers 12 each multiply one beam input signal 11 distributed by the distributor 10 by the updated excitation coefficient calculated by the excitation coefficient calculator 8.

[0025] The multiple multiplexing units 5 each multiplex a plurality of frequency-domain digital signals, which are digital signals output from the multiple DBF units 9 and which have been separated by frequency, on the frequency axis, and then convert the multiplexed signals into a time-domain digital signal. The digital signals output from the DBF units 9 are signals that form the basis of the beams 2 radiated from each of the antenna elements 1 described above. Each of the multiple multiplexing units 5 is connected to a different one of the multiple DACs 4.

[0026] Each of the plurality of DACs 4 converts into an analog signal the digital signal converted by the multiplexer 5 to which it is connected. Each of the plurality of DACs 4 is connected to a different one of the plurality of amplifiers 3.

[0027] Each of the plurality of amplifiers 3 amplifies the analog signal converted by the connected DAC 4. Furthermore, each of the plurality of amplifiers 3 is connected to a different one of the plurality of antenna elements 1.

[0028] Each of the multiple antenna elements 1 radiates an analog signal amplified by a connected amplifier 3 as radio waves. The multiple antenna elements 1 can form one beam 2 using two or more antenna elements 1, and can radiate multiple beams 2.

[0029] In the configuration of satellite transmitter 50 shown in FIG. 1, reflector unit 15 reflects radio waves emitted from a plurality of antenna elements 1, that is, array feed unit 14, and emits a plurality of beams 2 toward the ground.

[0030] In the satellite transmitter 50, as shown in FIGS. 1 and 2, an individual amplifier 3 is provided for each antenna element 1, but there is a limit to the output power of each amplifier 3, i.e., the maximum output power P max When the connected antenna element 1 is used only to form one beam 2, the power allocated to form one beam 2 is equal to the maximum output power P max However, if the connected antenna element 1 is a shared element used to form multiple beams 2, the amplifier 3 outputs a total power, which is the sum of the powers allocated to each beam 2 to form the multiple beams 2, as the maximum output power P max The power allocated to each beam 2 formed by the satellite transmitter 50 must be within this range. In addition, the maximum or minimum value of the power allocated to each beam 2 may be determined, for example, based on the system requirements included in the communication request. The satellite transmitter 50 determines the power allocated to each beam 2 so as to satisfy these constraints.

[0031] Therefore, in the first embodiment, the inter-beam weight calculation unit 7 of the satellite transmitter 50 calculates the maximum output power P max The inter-beam weight is calculated so that the sum of the radiated powers from the satellite transmitter 50, i.e., the total radiated power P, is maximized while satisfying constraints such as the power allocated to each beam 2. The total radiated power P of the satellite transmitter 50 determines the transmission capability of the satellite transmitter 50, i.e., the entire satellite on which the satellite transmitter 50 is mounted. Increasing the total radiated power P of the satellite transmitter 50 is equivalent to maximizing the satellite communication performance of the satellite transmitter 50.

[0032] Here, EIRP (Effective Isotropically Radiated Power) is an index that indicates the performance of a transmission system in wireless communication using an antenna. The EIRP of the satellite transmitter 50 is calculated by multiplying the power supplied to the antenna element 1 by the absolute gain G of the antenna element 1 in a given direction. j It can be calculated from the product of and expressed as equation (1).

[0033]

number

[0034] In equation (1), i is the element number of the antenna element 1, j is the beam number, N is the number of antenna elements 1 provided in the satellite transmitter 50, and M is the number of beams 2 formed by the satellite transmitter 50. The EIRP of each beam 2 is j is the absolute gain G of antenna element 1 based on the excitation coefficient j and the power P radiated from each antenna element 1 forming each beam 2 ij The sum of the power P j To maximize the EIRP of the satellite transmitter 50, the absolute gain G j However, in order to avoid changing the shape of beam 2, the excitation coefficient cannot be changed, so the absolute gain G j Therefore, the maximization of the EIRP of the satellite transmitter 50 and the maximization of the power radiated from each antenna element 1 are the same conditions. The total radiated power P i is the sum of the power of beam 2 using antenna element 1 connected as shown in equation (2).

[0035]

number

[0036] The total radiated power P radiated from antenna element 1 calculated by equation (2) i The maximum output power P max The power used per beam 2, P j is the power P radiated from the antenna element 1 used to form the beam 2. ij The power P used for each beam 2 emitted from the satellite transmitter 50 is expressed as the sum of the power P j The power ratio is used as the inter-beam weight.

[0037]

number

[0038] The total radiated power P of the satellite transmitter 50 is the total radiated power P radiated from all antenna elements 1 as expressed in equation (4). i or the power P used by all beams 2 j The sum of these values ​​is the same.

[0039]

number

[0040] Therefore, in the satellite transmitter 50, the inter-beam weight calculation unit 7 calculates the total radiated power P radiated from one antenna element 1. i ≦Maximum output power P of amplifier 3 max The inter-beam weight calculation unit 7 determines the inter-beam weight so as to maximize the total radiated power P of the satellite transmitter 50 while satisfying the power constraint condition. When constraint conditions are added by the system requirements included in the communication request, the inter-beam weight calculation unit 7 further determines the inter-beam weight so as to satisfy the constraint conditions by the system requirements.

[0041] 5 is a flowchart showing the operation of the satellite transmitter 50 according to the first embodiment. In the satellite transmitter 50, the inter-beam weight calculation unit 7 calculates inter-beam weights based on the excitation coefficients for beamforming stored in the storage unit 6 and the communication request generated by the communication request generation unit 13 so as to maximize the total radiated power P of the satellite transmitter 50 (step S101). The excitation coefficient calculation unit 8 calculates updated excitation coefficients for each beam 2 based on the excitation coefficients for beamforming and the inter-beam weights calculated by the inter-beam weight calculation unit 7 (step S102). The DBF unit 9 distributes the input beam input signal 11 into N, which is the number of antenna elements 1, and multiplies the distributed beam input signal 11 by the updated excitation coefficient calculated by the excitation coefficient calculation unit 8 (step S103). The multiplexing unit 5 multiplexes the frequency-domain digital signals, which have been demultiplexed for each frequency, on the frequency axis, and then converts them into a time-domain digital signal (step S104). The DAC 4 converts the digital signal into an analog signal (step S105). Amplifier 3 has a maximum output power P max The analog signal is amplified within a predetermined time (step S106). The antenna element 1 emits the amplified analog signal as a radio wave (step S107).

[0042] Next, the hardware configuration of the satellite transmitter 50 will be described. In the satellite transmitter 50, the antenna element 1 is a radiator that emits radio waves. The amplifier 3 is an amplification circuit. The DAC 4 is a digital-to-analog conversion circuit. The storage unit 6 is a memory. The multiplexer 5, the inter-beam weight calculation unit 7, the excitation coefficient calculation unit 8, the DBF unit 9, and the communication request generation unit 13 are realized by processing circuits. The processing circuit may be a memory that stores a program and a processor that executes the program stored in the memory, or it may be dedicated hardware. The processing circuit is also called a control circuit.

[0043] FIG. 6 is a diagram showing an example of the configuration of the processing circuit 90 of the satellite transmitter 50 according to the first embodiment, when the processing circuit is realized by a processor 91 and a memory 92. The processing circuit 90 shown in FIG. 6 is a control circuit and includes a processor 91 and a memory 92. When the processing circuit 90 is configured with the processor 91 and the memory 92, each function of the processing circuit 90 is realized by software, firmware, or a combination of software and firmware. The software or firmware is written as a program and stored in the memory 92. The processor 91 reads and executes the program stored in the memory 92 to realize each function of the processing circuit 90. That is, the processing circuit 90 includes the memory 92 for storing a program that results in the processing of the satellite transmitter 50 being executed. This program can also be said to be a program that causes the satellite transmitter 50 to execute each function realized by the processing circuit. This program may be provided by a storage medium on which the program is stored, or by other means such as a communication medium.

[0044] The above program can also be said to be a program that causes the satellite transmitter 50 to execute the following steps in a case where the satellite transmitter 50 is capable of radiating multiple beams 2 and is capable of forming one beam 2 using two or more antenna elements 1, and is equipped with multiple antenna elements 1 capable of radiating multiple beams 2, and multiple amplifiers 3, each connected to a different one of the multiple antenna elements 1: a first step in which the inter-beam weight calculation unit 7 calculates inter-beam weights indicating the power ratio between the multiple beams 2 based on beam forming excitation coefficients, which are excitation coefficients for forming the beam 2, so that the total radiation power P of the multiple beams 2 radiated from the satellite transmitter 50 is maximized; a second step in which the excitation coefficient calculation unit 8 calculates updated excitation coefficients based on the beam forming excitation coefficients and the inter-beam weights; and a third step in which multiple DBF units 9, the same number as the multiple beams 2, each use the updated excitation coefficient for one of the multiple beams 2 to generate a signal that is the basis of the beam 2 radiated from each antenna element 1 when radiating using the multiple antenna elements 1.

[0045] Here, the processor 91 is, for example, a CPU (Central Processing Unit), a processing device, an arithmetic device, a microprocessor, a microcomputer, or a DSP (Digital Signal Processor), etc. Furthermore, the memory 92 is, for example, a non-volatile or volatile semiconductor memory such as a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory, an EPROM (Erasable Programmable ROM), or an EEPROM (registered trademark) (Electrically EPROM), a magnetic disk, a flexible disk, an optical disk, a compact disk, a minidisk, or a DVD (Digital Versatile Disc).

[0046] FIG. 7 is a diagram showing an example of the configuration of the processing circuit 93 of the satellite transmitter 50 according to the first embodiment when the processing circuit is configured with dedicated hardware. The processing circuit shown in FIG. 7 corresponds to, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or a combination thereof. The processing circuit may be partially implemented with dedicated hardware and partially implemented with software or firmware. In this way, the processing circuit can realize each of the above-described functions by dedicated hardware, software, firmware, or a combination thereof.

[0047] As described above, according to this embodiment, in the satellite transmitter 50, the inter-beam weight calculation unit 7 calculates the inter-beam weight indicating the power ratio between the multiple beams 2 based on the beam forming excitation coefficients so that the total radiated power P of the multiple beams 2 radiated from the satellite transmitter 50 is maximized. The satellite transmitter 50 calculates the maximum output power P of the amplifier 3 based on the beam forming excitation coefficients. maxThe satellite transmitter 50 adjusts the amplitude of the power emitted for each beam 2 while satisfying the above constraints, and increases the amplitude of the power for beams 2 for which it is possible to increase the amplitude. This enables the satellite transmitter 50 to improve the total radiated power P, which is the sum of the radiated power of each beam 2 when forming multiple beams 2.

[0048] Embodiment 2 In the second embodiment, a specific method will be described in which the inter-beam weight calculation unit 7 calculates the inter-beam weight and the excitation coefficient calculation unit 8 calculates the excitation coefficient for each antenna element 1 of each beam 2 in the satellite transmitter 50.

[0049] In the second embodiment, the configuration of the satellite transmitter 50 is the same as that of the first embodiment shown in FIG. 1 or 2. In the satellite transmitter 50, the storage unit 6 is provided with an excitation coefficient table corresponding to a plurality of desired beams 2 and stores it in advance. The excitation coefficient table is given in true power values, without considering the phase, since only power is considered here. In addition, in the excitation coefficient table, the sum of the excitation coefficients for each antenna element 1 of each beam 2 is set to 1. When maximizing the total radiated power P, the shape of the beam 2 is not changed, that is, the ratio of the excitation coefficients of each antenna element 1 in each beam 2 is not changed, and only the inter-beam weight, which is the power ratio for each beam 2, can be changed. As explained in the first embodiment, one amplifier 3 is connected to each antenna element 1, and the total radiated power P of the beam 2 corresponding to each antenna element 1 is i is the maximum output power P of amplifier 3 max where the maximum output power P max The normalized power is set to 1. The total radiated power P is the sum of powers without considering the phase.

[0050] Fig. 8 is a diagram showing an example of an excitation coefficient table stored in the storage unit 6 of the satellite transmitter 50 according to the second embodiment. As shown in Fig. 8, excitation coefficients, which are power ratios corresponding to each of the beams 2-1 and 2-2, are given to the antenna elements 1-1 to 1-N. Fig. 8 shows, as an example, a case where the number of antenna elements 1 is N and the number of beams 2 is 2. Note that in Fig. 8, for the sake of simplicity, the antenna elements 1-1 to 1-N are represented by the suffixes 1 to N. This also applies to the subsequent figures. As mentioned above, since the sum of the excitation coefficients of each beam 2 is 1, a1 + a2 ... + a i …+a N =1, and b1+b2…+b i …+b N =1.

[0051] FIG. 9 shows the total radiation power P of each antenna element 1 when the inter-beam weight calculation unit 7 of the satellite transmitter 50 according to the second embodiment calculates the inter-beam weight. i 9 is a diagram showing an example of a calculation formula for the power used in each beam 2. In FIG. 9, the inter-beam weight for each beam 2 is expressed as a coefficient, and the total radiated power P i As shown in Figure 9, if the coefficient that is the inter-beam weight for beam 2-1 is X and the coefficient that is the inter-beam weight for beam 2-2 is Y, the total radiated power P i The power allocated to each antenna element 1 is a i X+b i Y. That is, the allocated power a i X+b i Y must be 1 or less due to the condition of the output power of the amplifier 3. Since the sum of the excitation coefficients of each beam 2 is 1, the total radiated power P of the satellite transmitter 50 is (a1 + a2 ... + a i …+a N )X+(b1+b2…+b i …+b N )Y = X + Y. Therefore, maximizing the total radiated power P of the satellite transmitter 50 is a matter of maximizing X + Y under the above output power conditions, where X ≥ 0 and Y ≥ 0.

[0052] 9 can be formulated as shown in equation (5). That is, X+Y is maximized under the conditions of the simultaneous inequalities. The inter-beam weight calculation unit 7 can calculate the inter-beam weight that maximizes the total radiated power P of the satellite transmitter 50 by solving this conditional equation using linear programming, for example, the simplex method.

[0053]

number

[0054] FIG. 10 is a first diagram showing a specific example of an excitation coefficient table stored in the storage unit 6 of the satellite transmitter 50 according to the second embodiment. FIG. 10 shows an example where the number of antenna elements 1, N, is 10 and the number of beams 2, M, is 2. The inter-beam weight calculation unit 7 calculates inter-beam weights for the excitation coefficient table shown in FIG. 10 so as to maximize the coefficients by linear programming or the like. FIG. 11 is a first diagram showing a specific example of excitation coefficients for beam forming updated by the excitation coefficient calculation unit 8 in the satellite transmitter 50 according to the second embodiment by multiplying the excitation coefficients for beam forming stored in the storage unit 6 by the inter-beam weights calculated by the inter-beam weight calculation unit 7. As shown in FIG. 11, the inter-beam weight calculation unit 7 calculates the inter-beam weight, which is the coefficient X for beam 2-1, to be 1.068 and the inter-beam weight, which is the coefficient Y for beam 2-2, to be 2.579. The excitation coefficient calculation unit 8 updates the excitation coefficients for beam forming stored in the storage unit 6 using the inter-beam weights calculated by the inter-beam weight calculation unit 7. As a result, the inter-beam weight calculation unit 7 can increase the total radiated power P of the satellite transmitter 50 to P=3.647 compared to the total radiated power P=2.000 of the satellite transmitter 50 before updating the excitation coefficients for beam forming shown in Fig. 10. The total radiated power P of the satellite transmitter 50 is calculated by multiplying X+Y by the maximum output power P of the amplifier 3. max , in this case multiplied by 1.

[0055] FIG. 12 is a second diagram showing a specific example of an excitation coefficient table stored in the storage unit 6 of the satellite transmitter 50 according to the second embodiment. FIG. 12 shows an example where the number of antenna elements 1, N, is 10 and the number of beams 2, M, is 3. The inter-beam weight calculation unit 7 calculates inter-beam weights for the excitation coefficient table shown in FIG. 12 so as to maximize the coefficients by linear programming or the like. FIG. 13 is a second diagram showing a specific example of excitation coefficients for beam forming updated by the excitation coefficient calculation unit 8 in the satellite transmitter 50 according to the second embodiment by multiplying the excitation coefficients for beam forming stored in the storage unit 6 by the inter-beam weights calculated by the inter-beam weight calculation unit 7. As shown in FIG. 13, the inter-beam weight calculation unit 7 calculates the inter-beam weight, which is the coefficient X for beam 2-1, to be 1.206, the inter-beam weight, which is the coefficient Y for beam 2-2, to be 1.373, and the inter-beam weight, which is the coefficient Z for beam 2-3, to be 1.250. The excitation coefficient calculation unit 8 updates the excitation coefficients for beam forming stored in the storage unit 6 using the inter-beam weights calculated by the inter-beam weight calculation unit 7. As a result, the inter-beam weight calculation unit 7 can increase the total radiated power P of the satellite transmitter 50 to P=3.829 compared to the total radiated power P=3.000 of the satellite transmitter 50 before updating the excitation coefficients for beam forming shown in Fig. 12. The total radiated power P of the satellite transmitter 50 is calculated by multiplying X+Y+Z by the maximum output power P of the amplifier 3. max , in this case multiplied by 1.

[0056] As described above, according to this embodiment, in the satellite transmitter 50, the inter-beam weight calculation unit 7 multiplies the corresponding beam forming excitation coefficient and inter-beam weight for each of the plurality of antenna elements 1, and adds the results for the plurality of beams 2 together to obtain the maximum output power P max An inequality is generated so that:

[0057] Embodiment 3 In embodiment 3, a case where simultaneous equations are used is described as a specific method in which the inter-beam weight calculation unit 7 calculates the inter-beam weight and the excitation coefficient calculation unit 8 calculates the excitation coefficient for each antenna element 1 of each beam 2 in the satellite transmitter 50.

[0058] In the third embodiment, the configuration of the satellite transmitter 50 is the same as that of the first embodiment shown in Fig. 1 or 2. Fig. 14 shows the total radiated power P i 14 is a diagram showing an example of constraints on the total radiated power P of each antenna element 1 described in FIG. i The power allocated to each antenna element 1 is a i X+b i The plot shows Y=1, with the shaded areas of each line being the solution area. The area that satisfies all equations, i.e., all inequalities, is the solution range 20 shown by the thick line, and the solution candidates 21 shown by circles are points where X+Y may be the maximum value. Therefore, the inter-beam weight calculation unit 7 calculates all points of the solution candidates 21 shown by circles, and finds the solution candidate 21 where X+Y is the maximum value, thereby calculating the inter-beam weight that maximizes the total radiated power P of the satellite transmitter 50.

[0059] Since the maximum value under the simultaneous inequalities is at the boundary of the range, the conditional expressions are connected with an equal sign, i X+b i Y=1 and a j X+b j It exists in the solution of the simultaneous equations with Y=1. In this case, the coefficient that maximizes X+Y from the simultaneous equations of all combinations is the maximum coefficient that is desired, that is, the inter-beam weight that maximizes the total radiated power P of the satellite transmitter 50. Here, if there are two unknown coefficients, it becomes a simultaneous equation with two unknowns, and if there are three unknown coefficients, it becomes a simultaneous equation with three unknowns. Similarly, if there are four or more unknown coefficients, the number of equations used in the simultaneous equations can be expanded. a i ,b iIn the case where the excitation coefficients are sparse and are 0, the simultaneous equations can be easily solved. Therefore, the beam weight calculation unit 7 calculates a i ,a j ,b i ,b j Only calculations are necessary if ≠ 0.

[0060] As described above, according to this embodiment, in the satellite transmitter 50, the inter-beam weight calculation unit 7 calculates inter-beam weights from the solution of simultaneous equations that connect with equality inequalities that form a region that satisfies the conditions of the simultaneous inequalities. The inter-beam weight calculation unit 7 can calculate inter-beam weights that satisfy the constraint conditions by mechanically finding a solution using a solution method that uses simultaneous equations.

[0061] Embodiment 4 In the fourth embodiment, a case will be described in which a minimum value of power to be allocated to a certain beam 2 is introduced as a constraint.

[0062] In the fourth embodiment, the configuration of the satellite transmitter 50 is the same as that in the first embodiment shown in Fig. 1 or 2. In the first to third embodiments, the power allocated to each beam 2 was constrained to be equal to or greater than 0, so there was a possibility that the allocated power would be 0. Even if the allocated power is not 0, it is conceivable that a minimum allocated power will be specified based on communication requirements, etc. Fig. 15 shows the total radiated power P for each antenna element 1 when there is a minimum power constraint on the allocated power in the satellite transmitter 50 according to the fourth embodiment. i 15 is a diagram showing an example of constraints expressed as an equation for the beam 2-2 coefficient Y. The example in FIG. 15 corresponds to a case where there are two beams 2 and there is a minimum power constraint 22 on the inter-beam weight, which is the coefficient Y of beam 2-2. Even when there is a minimum power constraint 22, the inter-beam weight calculation unit 7 can solve the problem by linear programming, for example, the simplex method, as described above. Note that the minimum power constraint 22 can be determined based on the communication request generated by the communication request generation unit 13, etc.

[0063] FIG. 16 is a diagram showing a specific example of an excitation coefficient table stored in the storage unit 6 of the satellite transmitter 50 according to the fourth embodiment. FIG. 16 shows an example where the number of antenna elements 1, N, is 10 and the number of beams 2, M, is 3. The inter-beam weight calculation unit 7 calculates inter-beam weights for the excitation coefficient table shown in FIG. 16 so as to maximize the coefficients by linear programming or the like. FIG. 17 is a first diagram showing a specific example of excitation coefficients for beam forming updated by the excitation coefficient calculation unit 8 in the satellite transmitter 50 according to the fourth embodiment by multiplying the excitation coefficients for beam forming stored in the storage unit 6 by the inter-beam weights calculated by the inter-beam weight calculation unit 7. As shown in FIG. 17, the inter-beam weight calculation unit 7 calculates the inter-beam weight, which is the coefficient X for beam 2-1, to be 2.44, the inter-beam weight, which is the coefficient Y for beam 2-2, to be 0.00, and the inter-beam weight, which is the coefficient Z for beam 2-3, to be 2.82. The excitation coefficient calculation unit 8 updates the excitation coefficients for beam forming stored in the storage unit 6 using the inter-beam weights calculated by the inter-beam weight calculation unit 7. As a result, the inter-beam weight calculation unit 7 can increase the total radiated power P of the satellite transmitter 50 to P=5.26 compared to the total radiated power P of the satellite transmitter 50 before updating the excitation coefficients for beam forming shown in Fig. 16, which was P=3.00. The total radiated power P of the satellite transmitter 50 is calculated by multiplying X+Y+Z by the maximum output power P of the amplifier 3. max , in this case multiplied by 1. Here, as shown in FIG. 17, the inter-beam weight, which is the coefficient for beam 2-2, is set to 0. In other words, this is an example in which the total radiated power P of the satellite transmitter 50 is greater when power is allocated to beams 2-1 and 2-3 and no power is allocated to beam 2-2. In this case, since no power is allocated to beam 2-2, beam 2-2 is not radiated and becomes an inoperative beam 2.

[0064] FIG. 18 shows the result when a power of 0.8 is assigned to beam 2-2 as the minimum power constraint 22. FIG. 18 is a second diagram showing a specific example of excitation coefficients for beam forming updated by the excitation coefficient calculation unit 8 in the satellite transmitter 50 according to embodiment 4 by multiplying the excitation coefficients for beam forming stored in the storage unit 6 by the inter-beam weights calculated by the inter-beam weight calculation unit 7. As shown in FIG. 18, the inter-beam weight calculation unit 7 calculates the inter-beam weight, which is the coefficient X for beam 2-1, to be 2.07, the inter-beam weight, which is the coefficient Y for beam 2-2, to be 0.80, and the inter-beam weight, which is the coefficient Z for beam 2-3, to be 1.76. The excitation coefficient calculation unit 8 updates the excitation coefficients for beam forming stored in the storage unit 6 using the inter-beam weights calculated by the inter-beam weight calculation unit 7. As a result, the inter-beam weight calculation unit 7 can increase the total radiated power P of the satellite transmitter 50 to P=4.63 compared to the total radiated power P=3.00 of the satellite transmitter 50 before updating the beamforming excitation coefficients shown in Figure 16, while satisfying the minimum power constraint 22.

[0065] As described above, according to this embodiment, in the satellite transmitter 50, the inter-beam weight calculation unit 7 can further calculate the inter-beam weight so as to satisfy the minimum power constraint 22, which is the condition for the minimum radiation power given to a certain beam 2.

[0066] Embodiment 5. In the fifth embodiment, a case will be described in which the maximum value of the power allocated to a certain beam 2 is introduced as a constraint.

[0067] In the fifth embodiment, the configuration of the satellite transmitter 50 is the same as that in the first embodiment shown in Fig. 1 or 2. When a maximum value for the power allocated to a certain beam 2 is introduced, an application example can be considered in which it is desired to suppress the amount of interference. Fig. 19 shows the total radiated power P for each antenna element 1 when there is a maximum power constraint 23 on the allocated power in the satellite transmitter 50 according to the fifth embodiment. i19 is a diagram showing an example of constraints expressed as an equation for the beam 2-2 coefficient Y. The example in FIG. 19 corresponds to a case where there are two beams 2 and there is a maximum power constraint 23 on the inter-beam weight, which is the coefficient Y of beam 2-2. Even when there is a maximum power constraint 23, the inter-beam weight calculation unit 7 can solve the problem by linear programming, for example, the simplex method, as described above. Note that the maximum power constraint 23 can be determined by the communication request generated by the communication request generation unit 13, etc.

[0068] Here, as explained in the fourth embodiment, when no additional constraints are set on the excitation coefficient table shown in Fig. 16, the excitation coefficients for beam forming are updated as shown in Fig. 17. As shown in Fig. 17, the inter-beam weight, which is the coefficient Z for beam 2-3, is 2.82. In the fifth embodiment, a case where 1.80 power is assigned to beam 2-3 as the maximum power constraint 23 will be specifically explained. Fig. 20 is a diagram showing a specific example of excitation coefficients for beam forming updated by the excitation coefficient calculation unit 8 in the satellite transmitter 50 according to the fifth embodiment by multiplying the excitation coefficients for beam forming stored in the storage unit 6 by the inter-beam weight calculated by the inter-beam weight calculation unit 7. As shown in Fig. 20, the inter-beam weight calculation unit 7 calculates the inter-beam weight, which is the coefficient X for beam 2-1, to be 2.08, the inter-beam weight, which is the coefficient Y for beam 2-2, to be 0.77, and the inter-beam weight, which is the coefficient Z for beam 2-3, to be 1.80. The excitation coefficient calculation unit 8 updates the excitation coefficients for beamforming stored in the storage unit 6 using the inter-beam weights calculated by the inter-beam weight calculation unit 7. As a result, the inter-beam weight calculation unit 7 can increase the total radiated power P of the satellite transmitter 50 to P=4.65 compared to the total radiated power P=3.00 of the satellite transmitter 50 before updating the excitation coefficients for beamforming shown in Fig. 16 while satisfying the maximum power constraint 23.

[0069] As described above, according to this embodiment, in the satellite transmitter 50, the inter-beam weight calculation unit 7 can further calculate the inter-beam weight so as to satisfy the maximum power constraint, which is the condition for the maximum radiation power given to a certain beam 2.

[0070] The configurations shown in the above embodiments are merely examples, and may be combined with other known technologies, or different embodiments may be combined with each other. It is also possible to omit or modify parts of the configurations as long as they do not deviate from the gist of the invention. [Explanation of symbols]

[0071] 1-1 to 1-N antenna elements, 2-1 to 2-M beams, 3-1 to 3-N amplifiers, 4-1 to 4-N DACs, 5-1 to 5-N multiplexers, 6 memory unit, 7 inter-beam weight calculator, 8 excitation coefficient calculator, 9-1 to 9-M DBF unit, 10 distributor, 11-1 to 11-M beam input signals, 12-1 to 12-N excitation coefficient multipliers, 13 communication request generator, 14 array feed unit, 15 reflector unit, 16, 17, 18 element range, 19 element beam, 20 solution range, 21 solution candidate, 22 minimum power constraint, 23 maximum power constraint, 40 array-fed reflector antenna, 50 satellite transmitter.

Claims

1. A transmitting device capable of simultaneously emitting multiple beams, a plurality of antenna elements capable of forming one beam using two or more antenna elements and radiating the plurality of beams; a plurality of amplifiers, each amplifier connected to a different one of the plurality of antenna elements; a memory unit that stores beamforming excitation coefficients, which are excitation coefficients for forming the beams; an inter-beam weight calculation unit that calculates inter-beam weights indicating power ratios between the plurality of beams based on the beamforming excitation coefficients so that a total radiated power of the plurality of beams radiated from the transmitting device is maximized; an excitation coefficient calculation unit that calculates updated excitation coefficients based on the beamforming excitation coefficients and the inter-beam weights; a plurality of digital beamforming units, the number of which is the same as the number of beams, each of which uses the updated excitation coefficient for one of the plurality of beams to generate a signal that is a basis of a beam radiated from each antenna element when radiating using the plurality of antenna elements; A transmitting device comprising:

2. the inter-beam weight calculation unit generates an inequality that multiplies the corresponding beamforming excitation coefficient by the inter-beam weight for each of the plurality of antenna elements, and adds up the results of multiplying the results for the plurality of beams to a maximum output power of the amplifier or less, and calculates the inter-beam weight so as to satisfy the conditions of the simultaneous inequalities corresponding to the plurality of antenna elements.

2. The transmitting device according to claim 1.

3. the inter-beam weight calculation unit calculates the inter-beam weight from a solution of a simultaneous equation obtained by connecting, with an equal sign, inequalities that form a region that satisfies the conditions of the simultaneous inequalities.

3. The transmitting device according to claim 2.

4. the inter-beam weight calculation unit further calculates the inter-beam weight so as to satisfy a minimum power constraint, which is a condition of a minimum radiation power given to a certain beam.

4. The transmitting device according to claim 2 or 3.

5. the inter-beam weight calculation unit further calculates the inter-beam weight so as to satisfy a maximum power constraint, which is a condition of maximum radiation power given to a certain beam.

4. The transmitting device according to claim 2 or 3.

6. A control circuit for controlling a transmitter capable of simultaneously emitting multiple beams, comprising: The transmitting device a plurality of antenna elements capable of forming one beam using two or more antenna elements and radiating the plurality of beams; a plurality of amplifiers, each amplifier connected to a different one of the plurality of antenna elements; It is equipped with calculating inter-beam weights indicating a power ratio between the plurality of beams based on beamforming excitation coefficients, which are excitation coefficients for forming the beams, so that a total radiated power of the plurality of beams radiated from the transmitting device is maximized; calculating updated excitation coefficients based on the beamforming excitation coefficients and the inter-beam weights; generating, for each of the plurality of beams, a signal that is a basis of a beam radiated from each antenna element when radiating using the plurality of antenna elements, using the updated excitation coefficient for one of the plurality of beams; A control circuit that causes the transmitting device to perform the above.

7. A storage medium storing a program for controlling a transmitting device capable of simultaneously emitting a plurality of beams, The transmitting device a plurality of antenna elements capable of forming one beam using two or more antenna elements and radiating the plurality of beams; a plurality of amplifiers, each amplifier connected to a different one of the plurality of antenna elements; It is equipped with The program calculating inter-beam weights indicating a power ratio between the plurality of beams based on beamforming excitation coefficients, which are excitation coefficients for forming the beams, so that a total radiated power of the plurality of beams radiated from the transmitting device is maximized; calculating updated excitation coefficients based on the beamforming excitation coefficients and the inter-beam weights; generating, for each of the plurality of beams, a signal that is a basis of a beam radiated from each antenna element when radiating using the plurality of antenna elements, using the updated excitation coefficient for one of the plurality of beams; A storage medium that causes the transmitting device to perform the above.

8. A transmission method for a transmitter capable of simultaneously emitting multiple beams, comprising: The transmitting device a plurality of antenna elements capable of forming one beam using two or more antenna elements and radiating the plurality of beams; a plurality of amplifiers, each amplifier connected to a different one of the plurality of antenna elements; Equipped with a first step in which an inter-beam weight calculation unit calculates inter-beam weights indicating a power ratio between the plurality of beams based on beamforming excitation coefficients, which are excitation coefficients for forming the beams, so that a total radiated power of the plurality of beams radiated from the transmitting device is maximized; a second step in which an excitation coefficient calculation unit calculates updated excitation coefficients based on the beamforming excitation coefficients and the inter-beam weights; a third step in which a plurality of digital beamforming units, the number of which is the same as the plurality of beams, each use the updated excitation coefficient for one of the plurality of beams to generate a signal that is a basis of a beam radiated from each of the plurality of antenna elements when radiating using the plurality of antenna elements; A transmission method comprising:

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