Multibeam antenna systems and wireless communication systems

Abstract

The multibeam antenna system comprises a single transmitting DBF antenna unit (101) which is a transmitting antenna, a plurality of PAA units (103) which are transmitting antennas configured on the same plane as the transmitting DBF antenna unit (101), and a single receiving DBF antenna unit (102) which is a receiving antenna.

Description

Technical Field

[0001] The technology described in this specification relates to a multi-beam antenna system and a wireless communication system.

Background Art

[0002] Regarding the coverage of mobile phone operators in each country, although the population coverage rate is high, the area coverage rate may be low.

[0003] For example, regarding the coverage of mobile phone operators in Japan, although it depends on the operator and frequency, the population coverage rate is at most about 99%, but the area coverage rate is at most about 70%, and at least about 30% of the national land area is not covered.

[0004] Therefore, a wireless communication device capable of covering a wide range has been proposed by mounting a planar division DBF (Digital Beam Forming) antenna on an artificial satellite (for example, Non-Patent Document 3).

[0005] FIG. 1 is a diagram schematically showing a configuration example of a wireless communication system 600 in a conventional example.

[0006] The wireless communication system 600 includes a multi-beam antenna system 60 and a USER on the ground 2, an airplane, and a HAPS (High Altitude Platform Station), which are not shown.

[0007] The multi-beam antenna system 60 includes one DBF Tx101 and one DBF Rx102 on the surface of the satellite body 3. Note that the satellite body 3 may be a HAPS.

[0008] DBF Tx101 is a common transmission system for a USER on the ground 2, an airplane, and a HAPS.

[0009] DBF Rx102 is a common reception system for a USER on the ground 2, an airplane, and a HAPS. [Prior art documents] [Non-patent literature]

[0010] [Non-Patent Document 1] Space Cellular Study Task Group, "Document 43-1: Report of the Space Cellular Study Task Group," Ministry of Internal Affairs and Communications, Information and Communications Council, February 3, 2021. [Non-Patent Document 2] Kenji Suematsu, Tomoyuki Furuichi, and Satoshi Tsukamoto, "Basic Study on the Configuration of a Q / V Band Direct Digital RF DBF Transceiver for Satellite Mounting," IEICE Technical Report, July 2023. [Non-Patent Document 3] Kenji Suematsu, Tomoyuki Furuichi, and Satoshi Tsukamoto, "Basic Study of Q / V Band DBF Antenna Device for LEO Constellation Satellites," IEICE Technical Report, vol. 123, no. 377, SAT2023-62, pp. 18-22, February 2024. [Non-Patent Document 4] Satoshi Suyama, Tatsuki Okuyama, Yuki Inoue, and Yoshihisa Kishiyama, "5G Multi-Antenna Technology," NTT DOCOMO Tech. Journal vol.23(4), pp.30-39, 2016. [Overview of the Initiative] [Problems that the invention aims to solve]

[0011] In conventional multi-beam antenna systems 60, it is possible to form many beams using DBF antennas, but there are limitations on the transmission power, and the bandwidth inevitably narrows as the number of beams increases.

[0012] In one respect, the technology described herein aims to provide wireless communication devices that cover a wide range and broadband. [Means for solving the problem]

[0013] In one respect, multibeam antenna systems are A multibeam antenna system mounted on an artificial satellite,One transmitting DBF (Digital Beam Forming) antenna unit on one side for transmission, a plurality of PAA (Phased Array Antenna transmitter) units on the same plane as the transmitting DBF antenna unit and also for transmission, and one receiving DBF antenna unit on one side for receiving The same plane is provided on the surface of the satellite body of the artificial satellite. is provided

Advantages of the Invention

[0014] As one aspect, a wireless communication device that covers a wide range and a wide band can be provided

Brief Description of the Drawings

[0015] [Figure 1] It is a diagram schematically showing a configuration example of a wireless communication system in a conventional example [Figure 2] It is a diagram schematically showing a configuration example of a wireless communication system in an embodiment [Figure 3] It is a block diagram schematically showing a configuration example of a communication device in an embodiment [Figure 4] It is a diagram schematically showing a configuration example of the antenna module of the transmission system shown in FIG. 1 [Figure 5] It is a diagram schematically showing a configuration example of the antenna module of the reception system shown in FIG. 1 [Figure 6] It is a block diagram schematically showing a hardware configuration example of the PAA Tx shown in FIG. 2 [Figure 7] It is a diagram schematically showing an arrangement example of the DBF Tx and PAA Tx on the surface of the satellite body facing the ground shown in FIG. 2

Modes for Carrying Out the Invention

[0016] Hereinafter, embodiments will be described with reference to the drawings. However, the embodiments shown below are merely examples, and there is no intention to exclude various modifications and applications of technologies not explicitly stated in the embodiments. That is, the present embodiment can be implemented with various modifications without departing from its gist.

[0017] Also, each figure does not mean that it only includes the components shown in the figure, and can include other components. Hereinafter, in the figures, parts with the same reference numerals indicate the same or similar parts unless otherwise specified.

[0018] 〔A〕Embodiment FIG. 2 is a diagram schematically showing a configuration example of a wireless communication system 100 in an embodiment.

[0019] The wireless communication system 100 includes a multi-beam antenna system 10 and USERs on the ground 2, airplanes, and HAPS (not shown).

[0020] The multi-beam antenna system 10 includes one DBF Tx101, a plurality (three in the example shown in FIG. 2) of PAA Tx103 (PAA Tx# of the surface of the satellite body #1~#3) and one DBF Rx102. Note that the satellite body 3 may be a HAPS. DBF Tx101 may be referred to as a transmission antenna unit, PAA Tx103 may be referred to as a PAA unit, and DBF Rx102 may be referred to as a receiving DBF antenna unit.

[0021] DBF Tx101 corresponds to a transmission system antenna module 12b described later using FIGS. 3 and 4, and DBF Rx102 corresponds to a receiving system antenna module 12a described later using FIGS. 3 and 5. An example of the hardware configuration of PAA Tx103 will be described later using FIG. 6.

[0022] DBF Tx101, DBF Rx102, and PAA Tx103 may each have the same number of antenna elements, and the transmission output of each antenna element may be equal.

[0023] Each PAA Tx103 transmits a single beam of broadband signal from multiple antennas to a broadband communication target such as an airplane, HAPS, or master station. In the example shown in Figure 2, PAA Tx#1 transmits a beam to airplane #1, PAA Tx#2 transmits a beam to HAPS#1, and PAA Tx#3 transmits a beam to airplane #2. In other words, n (where n is a natural number) PAA units communicate with n broadband communication targets.

[0024] While PAA can only form one beam per surface, it allows for broader bandwidth compared to DBF. PAA is suitable for beams targeting targets requiring broadband signals, such as HAPS, which are few in number.

[0025] The DBF Tx101 transmits multiple narrowband transmission signals from each of its multiple antennas to targets performing narrowband communication, such as USERs on the ground. In the example shown in Figure 2, the DBF Tx101 transmits beams to USERs #1 to #m on the ground. In other words, n (where n is a natural number) PAA units communicate with n targets performing broadband communication. In other words, m (where m is a natural number) transmitting DBF antenna units communicate with m targets performing narrowband communication. USERs may also be VSATs (small earth stations).

[0026] The DBF Rx102 is a common receiving system for USER 2 on the ground, airplanes, and HAPS.

[0027] Figure 3 is a schematic block diagram showing an example of the configuration of the wireless communication device 1 in the embodiment.

[0028] The wireless communication device 1 corresponds to the combination of DBF Tx101 and DBF Rx102 shown in Figure 2, and is attached to an artificial satellite located at an altitude of 1000 km to communicate with a wireless communication terminal (not shown) on the ground 2, and comprises a receiving unit 1a and a transmitting unit 1b as shown in Figure 3. The wireless communication device 1 may, for example, cover the Q / V band, with DL (Down Link) at 40 GHz and UL (Up Link) at 50 Hz.

[0029] In Figure 3, only one receiving unit 1a and one transmitting unit 1b are shown, but the wireless communication device 1 may have multiple receiving units 1a and multiple transmitting units 1b.

[0030] The receiving unit 1a comprises a plurality of receiving antenna modules 12a and a DSP unit 13a. The transmitting unit 1b comprises a plurality of transmitting antenna modules 12b and a DSP unit 13b. Details of the transmitting antenna modules 12b will be described later with reference to Figure 4, and details of the receiving antenna modules 12a will be described later with reference to Figure 5. The transmitting DSP unit 13b and the receiving DSP unit 13a are disclosed, for example, in Non-Patent Document 3.

[0031] Figure 4 is a schematic diagram showing an example configuration of the antenna module 12b of the transmitting system shown in Figure 1.

[0032] In the example shown in Figure 4, the antenna module 12b consists of four elements corresponding to ANT#1 to #4, and includes a QSFP module 121, a DAC / CDR 122 (Digital-Analog Converter / Clock Data Recovery), a BPF 123, an amplifier 127, an SPDT-SW 124 (Single-Pole Double-Throw Switch), a PA 125 (Power Amplifier), a 90deg.HYB circuit 126, and a DBF antenna 11.

[0033] The QSFP module 121 converts the optical signal received from the DSP unit 13b via the optical fiber into an electrical signal. The DAC / CDR 122 converts the digital signal output by the QSFP module 121 into an analog signal and separates the clock and data. The BPF 123 is, for example, a spurious rejection filter, which removes aliasing spurious signals when converting the digital signal back to an analog signal. The amplifier 127 amplifies the signal in the bandwidth that has passed through the BPF 123. The SPDT-SW 124 inputs the input from the amplifier 127 to one of the two PAs 125 in the subsequent stage. The PA 125 amplifies the output signal from the SPDT-SW 124. The 90deg.HYB circuit 126 outputs a signal to the antenna 11 such that the two output signals have a phase difference of 90°. The DBF antenna 11 transmits the beam.

[0034] Figure 5 is a schematic diagram showing an example configuration of the receiving system antenna module 12a shown in Figure 2.

[0035] The antenna module 12a, in the example shown in Figure 5, consists of four elements corresponding to ANT#1 to #4, and includes a DBF antenna 11, a 90deg.HYB circuit 126, an LNA 128, an SPDT-SW 124, an amplifier 127, a BPF 123, an S / H (Sample / Hold) circuit 129, a 4ch / 4Gsps ADC+P / S 130 (Analog Digital Converter + Parallel / Serial), and a 100GbE QSFP 121.

[0036] The DBF antenna 11 receives the received beam. The 90deg.HYB circuit 126 eliminates the phase difference between two input signals with a 90° phase difference. The LNA (Low Noise Amplifier) ​​128 amplifies the input signal. The SPDT-SW 124 inputs the input from either of the two LNAs 128 to the subsequent amplifier 127. The BPF 123 is, for example, a spurious rejection filter, which removes aliasing spurious signals when converting the analog signal back to a digital signal. The S / H circuit 129 discretizes (samples) the analog signal and keeps its voltage constant during the A / D conversion period. The ADC+P / S 130 converts the parallel analog signal into a serial digital signal. The QSFP module 121 converts the electrical signal into an optical signal and transmits it to the DSP unit 13a via an optical fiber.

[0037] Figure 6 is a schematic block diagram showing an example of the hardware configuration of the PAA Tx103 shown in Figure 2.

[0038] The PAA Tx103 includes one digital precoder 21, multiple IFFT (Inverse Fast Fourier Transform) 22, multiple +CP (Cycle Prefix) 23, multiple DACs 24, multiple upconverters 25, multiple variable phase shifters 26, and multiple antennas 27.

[0039] The digital precoder 21 preprocesses signals #1 to #M in order to match the impulse response of the transmission line, and inputs them to L IFFTs 22.

[0040] IFFT22 performs an inverse fast Fourier transform on a signal, converting it from the frequency domain to the time domain.

[0041] +CP23 mitigates the effects of signal interference caused by multipath.

[0042] The DAC24 converts digital signals to analog signals.

[0043] The upconverter 25 increases the frequency of the analog signal output from the DAC24.

[0044] The variable phase shifter 26 shifts the phase of the input signal by a predetermined angle.

[0045] Antenna 27 (#1~#N) T ) is directed towards a target performing broadband communication and transmits broadband transmission signals.

[0046] Figure 7 is a schematic diagram showing an example of the arrangement of DBF Tx101 and PAA Tx103 on the surface of the satellite body 3 facing the ground 2, as shown in Figure 2.

[0047] In the example shown in Figure 7, a single 256-element DBF antenna unit 101 is mounted on the same plane as the satellite body 3, and four 256-element PAA units 103 are provided. Although the receiving DBF antenna unit 102 is not shown in Figure 7, the receiving DBF antenna unit 102 may be mounted, for example, adjacent to the transmitting DBF antenna unit 101.

[0048] For example, if the transmission bandwidth of one antenna unit is set to 80 MHz, the DBF antenna unit 101 can form 40 beams with a 1 MHz bandwidth or 80 beams with a 500 kHz bandwidth on one surface, and the PAA 103 unit can form 4 beams with an 80 MHz bandwidth on four surfaces.

[0049] In the transmission system of the multi-beam antenna system 10, by aligning one DBF antenna unit 101 and multiple PAA units 103 on the same plane, it becomes possible to realize a small number of broadband beams (the number of beams equal to the number of PAAs) using the multiple PAA units 103 and a large number of narrowband beams using one DBF antenna unit 101.

[0050] This simplifies the antenna configuration and reduces costs. For the DSP section, since there is only one transmitter per PAA and DBF calculation is unnecessary, the computational load is approximately (256+4) / (256×4) ≈ 20% compared to the configuration shown in Figure 7 with five DBF antennas. This allows for simplified, lower-cost, and lower-power devices.

[0051] [B] Other The disclosed technology is not limited to the embodiments described above, and can be implemented in various ways without departing from the spirit of each embodiment. Each configuration and each process of each embodiment can be selected or combined as needed. [Explanation of Symbols]

[0052] 1: Wireless communication device 1a: Receiver 1b: Transmitter 11: DBF antenna 110: Basic Unit 12a, 12b: Antenna module 121, 134: QSFP modules 122: DAC / CDR 123: BPF 124: SPDT-SW 125: PA 126: 90deg.HYB circuit 127: Amplifier 128: LNA 129:S / H circuit 130: ADC+P / S 13a, 13b: DSP section 100, 600: Wireless communication system 2: Ground 3:Satellite body 10, 60: Multibeam antenna system 101: DBF Tx (Transmitting DBF Antenna Unit) 102: DBF Rx (Receiving DBF Antenna Unit) 103: PAA Tx (PAA unit) 21: Digital Precoder 22: IFFT 23 :+CP 24: DAC 25: Upconverter 26: Variable Phase Shifter 27: Antenna

Claims

1. A multibeam antenna system mounted on an artificial satellite, A single-sided transmitting DBF (Digital Beam Forming) antenna unit, which serves as the transmitting antenna, A transmitting antenna comprising a plurality of PAA (Phased Array Antenna Transmitter) units configured on the same plane as the transmitting DBF antenna unit, A receiving DBF antenna unit with one surface, which is a receiving antenna, Equipped with, A multi-beam antenna system in which the same plane is provided on the surface of the satellite body of the artificial satellite.

2. The number of antenna elements provided in the transmitting DBF antenna unit, the receiving DBF antenna unit, and the PAA unit are the same, and the transmission output of each antenna element is equal. The multibeam antenna system according to claim 1.

3. Each of the PAA units is assigned one beam of the broadband transmission signal, the transmitting DBF antenna unit is assigned multiple beams of the narrowband transmission signal, and the receiving DBF antenna unit is assigned all of the receiving beams. The multibeam antenna system according to claim 1.

4. A multibeam antenna system mounted on an artificial satellite, In a wireless communication device that communicates with at least n (where n is a natural number) aircraft, HAPS (High Altitude Platform Station), and ground base stations as targets for broadband communication, and with m (where m is a natural number) ground communication terminals or VSAT (small earth station) equipment as targets for narrowband communication, The transmitting antenna is composed of n PAA units and one DBF antenna unit, and the receiving antenna is composed of one DBF antenna unit. Multibeam antenna system.

5. The multibeam antenna system according to Claim 4, The n targets that perform the aforementioned broadband communication include at least one of an aircraft, a HAPS (High Altitude Platform Station), and a ground base station. m targets that perform the aforementioned narrowband communication, wherein the ground communication terminal or the VSAT (small earth station) equipment A wireless communication system equipped with the following features.

6. A single-sided transmitting DBF antenna unit, which is a transmitting antenna, A transmitting antenna comprising a single PAA unit configured on the same plane as the transmitting DBF antenna unit, A receiving DBF antenna unit with one surface, which is a receiving antenna, Equipped with, The PAA unit transmits broadband communications to one ground-based master station, the transmitting DBF antenna unit transmits narrowband communications to m (where m is a natural number) ground-based communication terminals, and the receiving DBF antenna unit handles communication with all of the master station and communication terminals. Multibeam antenna system.

7. A single-sided transmitting DBF (Digital Beam Forming) antenna unit which is a transmitting antenna, A transmitting antenna comprising a plurality of PAA (Phased Array Antenna Transmitter) units configured on the same plane as the transmitting DBF antenna unit, A receiving DBF antenna unit with one surface, which is a receiving antenna, Equipped with, Each of the PAA units is assigned one beam of the broadband transmission signal, the transmitting DBF antenna unit is assigned multiple beams of the narrowband transmission signal, and the receiving DBF antenna unit is assigned all of the receiving beams. Multibeam antenna system.

8. The number of antenna elements provided in the transmitting DBF antenna unit, the receiving DBF antenna unit, and the PAA unit are the same, and the transmission output of each antenna element is equal. The multibeam antenna system according to claim 7.

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