Ground-based station device, wireless communication system, and wireless communication method

Abstract

The purpose of the present invention is to provide a ground-based station device, a wireless communication system, and a wireless communication method that are optimized by system integration while utilizing existing equipment such as 5G.　A ground-based station device 100 comprises: a wireless unit that converts a plurality of baseband signals received from a base station in a terrestrial network via optical fibers into radio signals that use carrier frequencies; a frequency conversion unit that applies a different frequency shift to the frequency of each radio signal to convert the frequencies into frequencies arranged within a predetermined frequency band on a link to a relay station device in a non-terrestrial network; and a transmission unit that transmits a radio signal including a plurality of radio frequencies arranged within the predetermined frequency band toward the relay station device.

Description

Ground station device, wireless communication system, and wireless communication method

[0001] The present disclosure relates to a ground station device, a wireless communication system, and a wireless communication method that are capable of cooperating with existing facilities such as 5G and that constitute a non-terrestrial network.

[0002] The 3rd Generation Partnership Project (3GPP: registered trademark) is developing specifications for the 5th generation mobile communication system (5G, also known as New Radio (NR) or Next Generation (NG)), and is also developing specifications for the next generation, known as Beyond 5G, 5G Evolution, or 6G.

[0003] Furthermore, in order to provide various services to areas that could not be covered by the existing mobile communication networks (Public Land Mobile Networks (PLMNs)) that mainly use terrestrial networks, the introduction of non-terrestrial networks (NTNs) is expected. NTNs are composed of geostationary orbit satellites (GEOs), low earth orbit satellites (LEOs), and high-altitude platform stations (HAPSs).

[0004] Therefore, research is being conducted into communication methods and network architectures that can link terrestrial networks, including 5G networks, with stratospheric networks using HAPS (see Non-Patent Document 1). Such linkage between 5G networks and HAPS will enable the construction of a HAPS system while utilizing existing 5G facilities, such as radio base stations (gNBs).

[0005] Hinata Obara and five others, "Development of a 38GHz band wireless communication system linked to a 5G network using a high altitude platform (HAPS) - A new HAPS system configuration utilizing ground network facilities," IEICE University, March 2022

[0006] When utilizing the core network and radio base stations of the terrestrial network, it is necessary to define the demarcation point between the mobile communication network equipment operated by the mobile network operator (MNO) and the terrestrial gateway (GW) station provided by the HAPS operator.

[0007] For example, existing 5G radio base stations (gNBs) can be mainly composed of a Central Unit (CU) and a Distributed Unit (DU). However, if the antenna device (RU: Radio Unit) extending from the gNB is simply connected to the HAPS terrestrial gateway station, an RF (Radio Frequency) cable will be connected to the RU's antenna port to connect to the terrestrial gateway station, so no changes to existing 5G equipment are required and existing 5G equipment can be utilized to the maximum extent.

[0008] However, when connecting via RF cable, the RU has to have a power amplifier even though it does not need to transmit via an antenna. This results in a redundant design when viewed from the perspective of the entire system, and is not optimal in terms of equipment size and power consumption, so optimization through system integration is required.

[0009] Therefore, the following disclosure has been made in consideration of this situation, and aims to provide a ground station device, a wireless communication system, and a wireless communication method that are optimized through system integration while utilizing existing facilities such as 5G.

[0010] One aspect of the present disclosure is a terrestrial station device (100) including a radio unit (110) that converts a plurality of baseband signals received from a base station of a terrestrial network via optical fiber into radio signals using a carrier frequency, a frequency conversion unit (130) that applies different frequency shifts to the frequencies of the radio signals to convert them into frequencies located within a predetermined frequency band on a link to a relay station device of a non-terrestrial network, and a transmission unit (150) that transmits a radio signal including a plurality of radio frequencies located within the predetermined frequency band to the relay station device.

[0011] One aspect of the present disclosure is a terrestrial station device (100) including a first radio unit (110) that converts a first baseband signal received from a base station of a terrestrial network via an optical fiber into a first radio signal using a carrier frequency, a second radio unit (110) that converts a second baseband signal received from the base station into a second radio signal using a carrier frequency to which a frequency shift has been applied, a frequency conversion unit (130) that converts the frequencies of the first radio signal and the second radio signal into frequencies placed within a predetermined frequency band on a link to a relay station device of a non-terrestrial network, and a transmission unit (150) that transmits a radio signal including a plurality of radio frequencies placed within the predetermined frequency band to the relay station device.

[0012] One aspect of the present disclosure is a terrestrial station device (100) including a radio processing unit (170) that converts a plurality of baseband signals received from a base station of a terrestrial network via an optical fiber into radio frequencies to which different frequency shifts are applied, thereby converting the signals into frequencies located within a predetermined frequency band on a link to a relay station device of a non-terrestrial network, and a transmitting unit (150) that transmits a radio signal including the plurality of radio frequencies located within the predetermined frequency band to the relay station device.

[0013] One aspect of the present disclosure is a wireless communication method for a terrestrial station device (100), comprising the steps of: converting a plurality of baseband signals received from a base station of a terrestrial network via an optical fiber into radio signals using a carrier frequency; applying different frequency shifts to the frequencies of the radio signals to convert them into frequencies located within a predetermined frequency band on a link to a relay station device of a non-terrestrial network; and transmitting a radio signal including a plurality of radio frequencies located within the predetermined frequency band to the relay station device.

[0014] One aspect of the present disclosure is a wireless communication method for a terrestrial station device (100), comprising the steps of: converting a first baseband signal received from a base station of a terrestrial network via an optical fiber into a first radio signal using a carrier frequency; converting a second baseband signal received from the base station into a second radio signal using a carrier frequency to which a frequency shift has been applied; converting the frequencies of the first radio signal and the second radio signal into frequencies located within a predetermined frequency band on a link to a relay station device of a non-terrestrial network; and transmitting a radio signal including a plurality of radio frequencies located within the predetermined frequency band to the relay station device.

[0015] One aspect of the present disclosure is a wireless communication method for a terrestrial station device (100), including the steps of: converting a plurality of baseband signals received from a base station of a terrestrial network via an optical fiber into radio frequencies to which different frequency shifts have been applied, thereby converting the signals into frequencies located within a predetermined frequency band on a link to a relay station device of a non-terrestrial network; and transmitting a radio signal including the plurality of radio frequencies located within the predetermined frequency band to the relay station device.

[0016] One aspect of the present disclosure is a wireless communication system comprising a base station (50) of a terrestrial network and a terrestrial station device (100) connected to the base station via an optical fiber, wherein the base station comprises a transmitting unit that transmits a plurality of baseband signals via the optical fiber, and the terrestrial station device comprises a radio unit (110) that converts the plurality of baseband signals received from the base station via the optical fiber into radio signals using a carrier frequency, a frequency conversion unit (130) that applies different frequency shifts to the frequencies of the radio signals to convert them into frequencies located within a predetermined frequency band on a link to a relay station device (200) of a non-terrestrial network, and a transmitting unit (150) that transmits a radio signal including a plurality of radio frequencies located within the predetermined frequency band to the relay station device.

[0017] FIG. 1 is a diagram illustrating an example of the overall schematic configuration of a wireless communication system 10 according to this embodiment. FIG. 2 is a diagram illustrating an example of a functional division point connecting a base station and a terrestrial gateway station. FIG. 3 is a diagram illustrating an example of a configuration (option 1) employing RF division according to this embodiment. FIG. 4 is a diagram illustrating another example of a configuration (option 2) employing RF division according to this embodiment. FIG. 5 is a diagram illustrating an example of a configuration (option 1) employing fronthaul division according to this embodiment. FIG. 6 is a diagram illustrating another example of a configuration (option 2) employing fronthaul division according to this embodiment. FIG. 7 is a diagram illustrating another example of a configuration (option 3) employing fronthaul division according to this embodiment. FIG. 8 is a diagram illustrating an implementation example in which multiple MNOs are connected using RF division. FIG. 9 is a diagram illustrating an implementation example in which multiple MNOs are connected using fronthaul division. FIG. 10 is a diagram illustrating an implementation example in which multiple MNOs are connected using backhaul division. FIG. 11 is a diagram illustrating an implementation example in which multiple MNOs are connected using a combination of fronthaul division and backhaul division. FIG. 12 is a diagram illustrating an overview of frequency usage in a service link. FIG. 13 is a diagram illustrating an example of frequency multiplexing of multiple MNO signals according to this embodiment (option 1). Fig. 14 is a diagram showing another example (option 2) of frequency multiplexing of multiple MNO signals in this embodiment. Fig. 15 is a diagram showing another example (option 3) of frequency multiplexing of multiple MNO signals in this embodiment. Fig. 16 is a diagram showing an example of the hardware configuration of a radio base station, a terrestrial gateway station, a HAPS payload, and a UE.

[0018] Hereinafter, embodiments will be described with reference to the drawings. Note that the same or similar reference numerals are used to designate the same functions or configurations, and descriptions thereof will be omitted as appropriate.

[0019] (1) Overall Schematic Configuration Example of a Wireless Communication System Fig. 1 shows an overall schematic configuration example of a wireless communication system 10 according to this embodiment. As shown in Fig. 1, the wireless communication system 10 includes a radio base station 50 (hereinafter, gNB 50), a ground station device 100, a relay station device 200, and a UE 300. In Fig. 1, the ground station device 100 is a terrestrial gateway (GW) station, and the relay station device 200 is a HAPS relay station (e.g., a HAPS payload).

[0020] Figure 1 shows a configuration known as a bent-pipe (transparent relay) system, which utilizes a mobile network operator (MNO)'s core network and radio base station 50 to provide 4G and 5G radio signals directly to UE 300 via a terrestrial gateway station 100 and a HAPS payload 200.

[0021] The gNB 50 (gNode B) is a radio base station conforming to 5G (NR). The gNB 50 performs 5G wireless communication with the UE 300 via the terrestrial gateway station 100 and the HAPS payload 200. The gNB 50 may be connected to a 5G core network (CN) via a backhaul (link). Note that the gNB 50 and the UE 300 may support not only 5G but also other mobile communication methods, such as 4G / LTE (Long Term Evolution), Beyond 5G, 5G Evolution, or 6G.

[0022] The feeder link, which is the communication link between the terrestrial gateway station 100 and the HAPS payload 200, uses a high frequency band such as millimeter waves, and transmits signals from multiple cell beams over a wide bandwidth by wavelength multiplexing.

[0023] The HAPS payload 200 does not perform signal processing such as modulation and demodulation, but operates as a relay system that performs frequency conversion and power amplification between the feeder link and the service link.

[0024] The service link, which is a communication link between the HAPS payload 200 and the ground UE, simultaneously transmits spatially divided signals in multiple cell beams using, for example, a 4G or 5G frequency band available to the UE 300. The service link may also use a frequency (2.7 GHz or less) allocated for HAPS among the 4G or 5G frequencies available to the UE 300.

[0025] (2) Overview of the Demarcation Point How to define the demarcation point between the existing facilities operated by the mobile network operator (MNO) and the ground gateway station provided by the HAPS operator is important for system integration.

[0026] FIG. 2 shows an example of a functional division point where a base station and a terrestrial gateway station are connected.

[0027] FIG. 2(a) shows an example of an RF splitting option.

[0028] In RF division, RUs extending from 5G network base stations (CU / DU) are connected to the HAPS gateway function of the terrestrial gateway station via RF cables. This RF division allows maximum utilization of the mobile communication network facilities operated by mobile network operators (MNOs). In order to utilize all of the core network, base stations (CU / DU) and radio units (RU), the input / output interface with the terrestrial gateway station is RF signals (e.g., 2 GHz band).

[0029] Figure 2(b) shows an example of a fronthaul splitting option.

[0030] With fronthaul splitting, the core network and base stations (CU / DU) of the mobile communications network equipment are utilized, and an interface using a fronthaul optical fiber transmission line is used for input and output with the terrestrial gateway station. Specific fronthaul interfaces that can be applied include CPRI (Common Public Radio Interface) or eCPRI for LTE, and O-RAN (Open RAN) standards for 5G. HAPS operators have the potential to integrate the gateway functions of the RU and HAPS into an optimized terrestrial gateway station (joint optimization), potentially reducing equipment size and power consumption.

[0031] Figure 2 (c) shows an example of a backhaul split option. In backhaul split, only the core network is used for mobile communication network equipment, and the HAPS operator provides a terrestrial gateway station that integrates base station, RU, and HAPS gateway functions. Because the system also includes base stations, there is the greatest room for optimization (joint optimization).

[0032] (3) Configuration of this Embodiment This embodiment shows an example assuming a system with 8-carrier multiplexing using 4-beam and 2-layer MIMO multiplexing in the service link.

[0033] (3.1) Configuration Example Using RF Division (i) Option 1 Fig. 3 shows a configuration example (Option 1) employing RF division in this embodiment. In Fig. 3, the gNB 50 and the terrestrial GW station 100 (for example, the HAPS GW 100) are connected by eight RF cables (S-band), and RF signals are exchanged.

[0034] The gNB 50 is composed of a CU and DU. The CU and DU may be installed in an integrated configuration or in a remote location. Four RUs are connected to the gNB 50 via optical fiber, and an interface conforming to the O-RAN standard is applied. Therefore, the DU of the gNB 50 may be an O-DU (O-RAN Distribution Unit).

[0035] The radio unit 51 is, for example, a radio unit (RU), and may be an O-RAN Radio Unit (O-RU) when an O-RAN interface is applied. One RU has two antenna ports and corresponds to one cell, so Figure 3 shows an example of a four-cell configuration. The radio unit 51 includes a function for converting between fronthaul optical line signals and analog OFDM signals.

[0036] The HAPS GW 100 is composed of a duplexer DUP 120, a frequency conversion unit 130, a multiplexing / demultiplexing unit 140, and a radio transceiver unit 150. The HAPS GW 100 frequency-multiplexes and transmits signals from each cell on the feeder link.

[0037] The duplexer DUP120 is connected to the antenna port of the RU in a one-to-one correspondence and includes a function for separating the uplink and downlink frequencies.

[0038] The frequency conversion unit 130 is composed of, for example, 16 analog frequency converters. The frequency conversion unit 130 applies different frequency shifts to the frequency of the radio signal to convert it into a frequency within a predetermined frequency band on the link to the relay station device. Because a high frequency band (e.g., Q-band) such as millimeter waves is used for the feeder link between the HAPS payload 200, the frequency conversion is performed by applying a frequency shift so that the radio signals from each cell can be multiplexed in the high frequency band (upconversion). Specifically, to frequency-multiplex and transmit signals from four cells over the feeder link, the signals from each cell antenna port are multiplexed by shifting their frequencies. The reverse conversion (downconversion) is also performed on the radio signals received from the feeder link.

[0039] The multiplexing / demultiplexing unit 140 is composed of, for example, a multiplexer (MUX) and a demultiplexer (DEMUX), and multiplexes multiple frequencies in the frequency domain and outputs them as a frequency-multiplexed signal, or separates each radio frequency from the frequency-multiplexed signal and outputs it.

[0040] The radio transceiver unit 150 is composed of, for example, a radio transmitter (TX RF), a radio receiver (RX RF), and an antenna, and relays frequency-multiplexed radio signals to the HAPS payload 200 located in the sky using a high frequency band, for example, millimeter waves.

[0041] In this way, in Option 1, the HAPS GW100 can be connected to the RU51 of the base station (CU / DU)50 via an RF cable, making it possible to make maximum use of much of the existing equipment in the terrestrial network.

[0042] (ii) Option 2 FIG. 4 shows another example of the configuration (option 2) that employs RF division in this embodiment.

[0043] The multiplexer / demultiplexer 160 is composed of, for example, a multiplexer (MUX) and a demultiplexer (DEMUX).

[0044] The differences from Figure 3 are that in Figure 4, some radio units 51, specifically RU#2 to RU#4, are configured to apply a predetermined frequency shift within a predetermined band (S-band) for each RU as the radio frequency for carrying signals, and that in HAPS GW100, the multiplexing and demultiplexing unit 160 multiplexes and demultiplexes the radio frequencies of RU#1 to RU#4 for each antenna port, and inputs and outputs them to the frequency conversion unit 130.

[0045] As described above, compared to Option 1, Option 2 can reduce the number of frequency conversion units 130, specifically the number of analog frequency converters, from 16 to 4, making it possible to reduce power consumption and miniaturize the HAPS GW100.

[0046] (3.2) Configuration Example with Fronthaul Splitting (i) Option 1 Fig. 5 shows a configuration example (option 1) that employs fronthaul splitting in this embodiment. In Fig. 5, the gNB 50 and the HAPS GW 100 are connected by four optical fibers.

[0047] The gNB 50 is composed of a CU / DU. The CU / DU may be installed in an integrated configuration, or may be installed in remote locations as an extended configuration. The gNB 50 has an O-DU that is connected to the HAPS GW 100 via, for example, an interface conforming to the O-RAN standard.

[0048] On the other hand, the HAPS GW 100 is composed of a radio unit 110, a duplexer (DUP) 120, a frequency conversion unit 130, a multiplexing / demultiplexing unit 140, and a radio transmitting / receiving unit 150.

[0049] The radio unit 110 may be, for example, radio units RU#1 to RU#4, which may be O-RUs connected to the gNB 50 via an interface conforming to the O-RAN standard. Since one RU has two antenna ports and corresponds to one cell, FIG. 5 shows an example of a four-cell configuration. Each antenna port is connected one-to-one to the duplexer 120 via an RF cable (S-band). The radio frequency from the antenna port is input / output to / from the frequency conversion unit 130 via the duplexer DUP120.

[0050] The RU includes a function for converting between fronthaul optical line signals and analog OFDM signals (radio signals). Specifically, in the case of an O-RU, the O-RU receives an IQ sampling sequence (also called a baseband signal) of a frequency-domain OFDM signal after processing such as encoding and scrambling of the user bit sequence from the O-DU. The IQ sampling sequence is then converted to a time-domain OFDM signal using an Inverse Fast Fourier Transform (IFFT) process, and then converted to an analog signal. The radio unit 110 may constitute a radio unit that converts multiple baseband signals received from base stations of a terrestrial network via optical fiber into radio frequencies using a carrier frequency. In this case, the O-DU of the gNB 50 may constitute a transmitter that transmits the multiple baseband signals.

[0051] The duplexer DUP120 includes a function for separating the uplink and downlink frequencies.

[0052] The frequency conversion unit 130 may be configured with, for example, 16 analog frequency converters. The frequency conversion unit 130 may apply different frequency shifts to the frequency of the radio signal to convert it into a frequency within a predetermined frequency band on the link to the relay station device of the non-terrestrial network. Because a high frequency band (e.g., Q-band) such as millimeter waves is used for the feeder link with the HAPS payload 200, the radio signals from each cell are frequency-converted by applying a frequency shift so that they can be multiplexed in the high frequency band (upconversion). Specifically, to frequency-multiplex and transmit signals from four cells on the feeder link, the frequencies of the signals from each cell antenna port are shifted and multiplexed. For example, to prevent the frequencies of the radio signals from each cell antenna port from overlapping on the feeder link, different frequency shift amounts may be set based on the cell and / or antenna port, and the set frequency shift amount may be applied to the radio frequency of the signal from each cell antenna port. Furthermore, on the feeder link after frequency multiplexing, the frequencies of the signals from each cell antenna port may be multiplexed at predetermined intervals or with some gaps. Moreover, the reverse conversion (down-conversion) is performed on radio signals received from the feeder link.

[0053] The multiplexing / demultiplexing unit 140 is composed of, for example, a multiplexer (MUX) and a demultiplexer (DEMUX), and multiplexes multiple frequencies in the frequency domain and outputs them as a frequency-multiplexed signal, or separates each radio frequency from the frequency-multiplexed signal and outputs it.

[0054] The wireless transceiver 150 is configured, for example, with a wireless transmitter (TX RF), a wireless receiver (RX RF), and an antenna, and relays frequency-multiplexed wireless signals using a high frequency band, for example, millimeter waves, between the HAPS payload 200 located in the sky. The wireless transceiver 150 may constitute a transmitter that transmits wireless signals including multiple wireless frequencies arranged within a predetermined frequency band to a relay station device.

[0055] In this way, compared to Option 1 with RF division, Option 1 reduces the number of cables from eight to four, simplifying installation. In addition, because optical fiber is used instead of RF cables, even base stations deployed in remote locations can be connected to the HAPS GW100, improving scalability.

[0056] (ii) Option 2 FIG. 6 shows another configuration example (option 2) that employs fronthaul division in this embodiment.

[0057] The multiplexer / demultiplexer 160 is composed of, for example, a multiplexer (MUX) and a demultiplexer (DEMUX).

[0058] The difference from Figure 5 is that Figure 6 is configured so that RU#2 to RU#4 use a radio frequency to carry signals with a predetermined frequency shift within a predetermined band (S-band) for each cell, and that the multiplexing / demultiplexing unit 160 multiplexes and demultiplexes the radio frequencies of RU#1 to RU#4 for each antenna port, and inputs and outputs them to the frequency conversion unit 130.

[0059] Specifically, the carrier frequencies of signals from the four cells are shifted in the S-band. For example, in RU#2 to RU#4, different frequency shift amounts may be set based on the cell so that the carrier frequencies of signals from each of the four cell antenna ports do not overlap in the S-band, and the frequency shift amount may be applied to the carrier frequency of the cell. RU#1 of the radio unit 110 may constitute a first radio unit that converts a first baseband signal received from a base station of a terrestrial network via optical fiber into a first radio frequency using the carrier frequency. RU#2 to RU#4 of the radio unit 110 may constitute a second radio unit that converts a second baseband signal received from a base station via optical fiber into a second radio frequency using a frequency-shifted carrier frequency.

[0060] The frequency converter 130 performs frequency conversion (upconversion) for frequency multiplexing and transmission on the feeder link for each antenna port. The frequency converter 130 may be configured as a frequency converter that converts the frequencies of the first radio signal (radio signal from RU#1) and the second radio signal (at least one of the radio signals from RU#2 to RU#4) into frequencies located within a predetermined frequency band on the link to the relay station device of the non-terrestrial network.

[0061] In this way, compared to Option 1, Option 2 can reduce the number of frequency conversion units 130, specifically the number of analog frequency converters, from 16 to 4, making it possible to reduce power consumption and miniaturize the HAPS GW100.

[0062] (iii) Option 3 FIG. 7 shows another configuration example (option 3) that employs fronthaul division in this embodiment.

[0063] 5 and 6 in that Fig. 7 includes a digital processor 170 that digitally applies the frequency shift required to place each of the multiple signals received over multiple O-RAN-compliant interfaces at a predetermined position within a predetermined frequency band (Q-band) on the feeder link, and that a TRX (Transmitter-Receiver) in the RU is not required. This predetermined frequency band may be the frequency band on the feeder link.

[0064] The digital processing unit 170 is composed of, for example, a DSP (Digital Signal Processor). The digital processing unit 170 converts multiple baseband signals received from a base station via optical fiber into radio frequencies with different frequency shifts applied, thereby converting the signals into frequencies within a predetermined frequency band on a link to a relay station device of a non-terrestrial network. Specifically, to frequency-multiplex and transmit signals from four cells over a feeder link, the frequencies of the signals from each cell antenna are shifted and multiplexed. For example, to prevent the frequencies of the radio signals from each cell antenna port (or equivalent) from overlapping on the feeder link, different frequency shift amounts may be set based on the cell and / or antenna port (or equivalent), and the set frequency shift amount may be applied to the radio frequency of the signal from each cell antenna port (or equivalent). Furthermore, on the feeder link after frequency multiplexing, the frequencies of the signals from each cell antenna port (or equivalent) may be multiplexed at predetermined intervals or with some gaps. Furthermore, the reverse conversion is performed on the radio signals received from the feeder link.

[0065] As such, compared to Options 1 and 2, Option 3 eliminates the need for frequency conversion units, specifically, analog frequency converters and power amplifiers within the RU, enabling significant reductions in power consumption and equipment size.

[0066] (4) Expansion to Multiple Mobile Network Operators (MNOs): A configuration in which multiple mobile network operators (MNOs) share a HAPS system will be described. The mobile network operators (MNOs) may be included in the telecommunications carriers.

[0067] (4.1) Example of connection configuration Below, we will show an implementation example in which multiple mobile network operators (MNOs) share a HAPS system and connect each company's network to a terrestrial gateway station (HAPS GW).

[0068] (i) Option 1 Figure 8 shows an implementation example of connecting multiple mobile network operators (MNOs) using RF splitting.

[0069] In Fig. 8, multiple mobile network operators (MNOs) A, B, and C each connect their existing 5G network RUs to the HAPS GW function of a terrestrial gateway station via an RF interface using RF cables (S-band). In this case, in Fig. 3 and Fig. 4 showing the RF division, RU#1 to RU#4 correspond to the RUs of either Company A, Company B, or Company C, and the duplexer 120 of the HAPS GW 100 may constitute a receiving unit that receives signals from each company.

[0070] The terrestrial gateway station 100 converts the frequencies of the signals from companies A, B, and C together into a frequency on the feeder link and transmits it to the HAPS payload 200. On this feeder link, frequency multiplexing may be used as described later in Figures 13, 14, and 15.

[0071] The HAPS payload 200 applies multiple beams to the service link frequency and transmits them to the ground, allowing the UE to receive communication services in the frequency bands allocated to each company. Specifically, as shown in Fig. 8, the HAPS payload 200 controls four beams with different directions within the frequency bands allocated to companies A, B, and C on the service link to cover the ground with four cells, and transmits signals from multiple cells / beams in a spatially divided manner to provide communication services to the UE in each cell.

[0072] In Fig. 8, the three companies use consecutive frequency bands for the service link, but other frequency usage methods may be used as will be described later with reference to Fig. 12. Also, in Fig. 8, an example of a multi-beam beam pattern common to all companies is shown, but the three companies may use individual beam patterns.

[0073] In this way, Option 1 allows multiple mobile network operators (MNOs) to use their existing network facilities as is, making it easy to provide HAPS services to UEs.

[0074] (ii) Option 2 Figure 9 shows an implementation example of connecting multiple mobile network operators (MNOs) using fronthaul splitting.

[0075] The difference from Figure 8 is that in Figure 9, multiple mobile network operators (MNOs) A, B, and C connect the DUs of their existing 5G networks to the RUs of terrestrial gateway stations via optical fibers (for example, O-RAN standard interfaces). In this case, the optical fibers shown in Figures 5, 6, and 7, which show fronthaul division, connect to the base stations of either Company A, Company B, or Company C.

[0076] In this case, part of the radio section 110 shown in FIG. 5 or FIG. 6 or the digital processing section 170 shown in FIG. 7 may constitute a receiving section that receives signals from each company.

[0077] In this way, compared to Option 1, Option 2 simplifies the existing network equipment of multiple mobile network operators (MNOs) by using optical fiber and utilizing the O-RAN standard interface, and can be used even if the location of the terrestrial gateway station and the location of each company's network equipment are far apart.

[0078] (iii) Option 3 Figure 10 shows an implementation example of connecting multiple mobile network operators (MNOs) with backhaul splitting.

[0079] The difference from Figures 8 and 9 is that in Figure 10, multiple mobile network operators (MNOs), Company A, Company B, and Company C, each connect their existing 5G core networks to a terrestrial gateway station via optical fiber (for example, an NG standard interface). The CU function of the terrestrial gateway station includes a receiver (not shown) that receives signals from each company.

[0080] In this way, Option 3 allows each company's core network to be connected via optical fiber to a terrestrial gateway station with base station functions provided by the HAPS operator, making it easy to connect without relying on the configuration of each company's base station.

[0081] (iv) Option 4 FIG. 11 shows an example implementation of connecting multiple mobile network operators (MNOs) using a combination of fronthaul and backhaul splitting.

[0082] In Figure 11, only the base station (CU / DU) of company A is connected to the terrestrial gateway station via optical fiber using an interface conforming to the O-RAN standard. This is an implementation example in which companies B and C connect their respective core networks to company A's base station via optical fiber using an interface conforming to the NG standard. The interface conforming to the O-RAN standard may be a first type of connection interface, and the interface conforming to the NG standard may be a second type of connection interface. The DU of the base station 50 may constitute a transmission unit.

[0083] In this way, Option 4 makes it possible to connect to terrestrial gateway stations depending on the existing facilities of each mobile network operator (MNO), allowing for flexible sharing of HAPS services.

[0084] Although FIG. 11 shows an example of a combination of fronthaul division and backhaul division, it is also possible to combine any of RF division, fronthaul division, and backhaul division.

[0085] (4.2) Example of frequency usage for service links When multiple mobile network operators (MNOs) share HAPS services, each company will provide communication services to UEs on the ground via a shared terrestrial gateway station and relay station equipment in the sky. The service link between the relay station equipment and UEs on the ground will use multi-beam transmission using the 4G or 5G frequency bands allocated to each mobile network operator (MNO). In this case, the feeder link between the terrestrial gateway station and relay station equipment must multiplex signals from each mobile network operator (MNO) according to the number of beams in the multi-beam, and a corresponding frequency shift is required.

[0086] FIG. 12 shows an overview of frequency usage in the service link.

[0087] Figure 12(a) shows an example (Option 1) in which each company uses a contiguous frequency band for HAPS services, just like for terrestrial networks. For example, each company uses a contiguous 20 MHz bandwidth.

[0088] Figure 12 (b) shows an example (Option 2) in which each company uses frequency bands at regular intervals for HAPS services. For example, of the 20 MHz bands allocated to each company, the highest frequency band of 10 MHz is used for HAPS services.

[0089] Figure 12 (c) shows an example (Option 3) in which each company freely uses frequency bands for HAPS services. The frequency bands that each company uses for HAPS services must be coordinated with the frequency usage of terrestrial networks, so the frequency bands available for HAPS use by each company may differ. For example, Company A may use the entire 20 MHz bandwidth, Company B may use the higher 10 MHz of the 20 MHz bandwidth, and Company C may use the lower 10 MHz of the 20 MHz bandwidth.

[0090] Figure 12(d) shows an example (Option 4) in which a dedicated frequency band for HAPS use is secured and shared by all companies, unlike Figure 12(a), (b), and (c). In this case, each company can use available bands in the dedicated frequency band as appropriate.

[0091] In addition, there are two methods for using multi-beam beam patterns in service links: one is to use a common beam pattern for each company, and the other is to use an independent beam pattern for each company. The two beam patterns can be applied to any of the four frequency usage methods shown in Figure 12.

[0092] When the common beam patterns of all the companies are applied to Figures 12(a), (b), and (c), a wide frequency bandwidth can be obtained, as will be described later in Figures 13, 14, and 15, but there are various options for frequency multiplexing methods in feeder links.

[0093] When a common beam pattern for all companies is applied as shown in Figure 12(d), the level is equivalent to that of operation by a single telecommunications carrier, and the system can be simplified.

[0094] (4.3) Example of Feeder Link Frequency Usage When multiple mobile network operators (MNOs) share HAPS services, this section describes how to multiplex each company's frequency on the feeder link.

[0095] 13, 14 and 15 show frequency multiplexing methods for frequencies of each company on a feeder link when a beam pattern (number of beams: 4) common to all companies is adopted.

[0096] FIG. 13 shows an example (option 1) of frequency multiplexing of signals from multiple MNOs in this embodiment, in which consecutive frequencies are used for each company's frequency.

[0097] Figure 13 (a) shows an example in which the order of frequencies for each company is maintained within each beam. For example, within beam #1, the order of frequencies for companies A, B, and C is maintained in the same order as the service link, and is frequency multiplexed on the feeder link with other beams #2 to #4. In this example, the terrestrial gateway station applies a large frequency shift to the consecutive frequencies of each company's signal for each beam, and frequency conversion can be performed collectively for each company's frequency, which has the advantage that frequency conversion for each beam can be performed in one step. This is easy to implement.

[0098] Figure 13(b) shows an example of arranging beams collectively for each company. For example, the frequencies of Company A's signals are arranged collectively from Beam #1 to Beam #4. In this example, the terrestrial gateway station first applies a small frequency shift to each beam, and then applies a large frequency shift to each company so that the order is the same as the order of the frequencies of each company in the service link. This is a two-step implementation.

[0099] FIG. 14 shows another example (option 2) of frequency multiplexing of signals from multiple MNOs in this embodiment, in which each company uses frequency bands at regular intervals.

[0100] Figure 14 (a) shows an example in which the spacing between the frequencies of each company is maintained within each beam. That is, for example, in beam #1, the spacing between the frequencies of companies A, B, and C is maintained the same as the spacing between the frequencies in the service link, and these are frequency-multiplexed on the feeder link together with other beams #2 to #4. In this example, the terrestrial gateway station applies a large frequency shift to the frequencies of each company's signal, which are spaced at regular intervals, for each beam. Since frequency conversion can be performed collectively for each company's frequency, there is the advantage that frequency conversion for each beam can be completed in one step. Note that if the frequency spacing within each beam is narrowed to avoid gaps on the feeder link, further frequency shifts may be applied.

[0101] Figure 14(b) shows an example in which beams are grouped together for each company. For example, the frequencies of Company A's signals are grouped together from beams #1 to #4. In this example, the terrestrial gateway station first applies a small frequency shift to each beam, and then applies a frequency shift to each company so that the order of frequencies is the same as the order of the company frequencies in the service link. This is a two-step implementation, but it allows for compact frequency multiplexing on the feeder link.

[0102] FIG. 15 shows another example (option 3) of frequency multiplexing of signals from multiple MNOs in this embodiment, in which each company freely uses the frequency band.

[0103] Figure 15 (a) shows an example in which the frequency spacing of each company is maintained within each beam. That is, for example, in beam #1, the frequency spacing of companies A, B, and C is maintained the same as the frequency spacing in the service link, and is frequency-multiplexed on the feeder link together with other beams #2 to #4. In this example, the terrestrial gateway station applies a large frequency shift to the frequencies of each company's signal at a predetermined interval for each beam. Since frequency conversion can be performed collectively for each company's frequency, there is an advantage that frequency conversion for each beam can be completed in one step. Note that if the frequency spacing within each beam is narrowed to avoid gaps on the feeder link, further frequency shifts may be applied.

[0104] Figure 15(b) shows an example in which beams are allocated together for each company. That is, for example, the frequencies of Company A's signals are allocated together from the frequencies of Beams #1 to #4. In this example, the terrestrial gateway station first applies a frequency shift for each beam, and then applies a frequency shift for each company so that the order is the same as the order of the frequencies for each company in the service link. This is a two-step implementation. The amount of frequency shift for each beam may be the same for each company, or may be different for each company so that no gaps occur.

[0105] The frequency multiplexing methods shown in FIGS. 13, 14, and 15 can be applied to the terrestrial gateway stations 100 shown in FIGS.

[0106] The frequency conversion unit 130 of the terrestrial GW station 100 shown in Figures 4 to 6 and the digital processing unit 170 of the terrestrial GW station shown in Figure 7 may constitute a frequency conversion unit that applies a frequency shift to the radio frequencies carrying the signals of each of the multiple telecommunications carriers, and converts the frequencies of the multiple telecommunications carriers into frequencies arranged at predetermined intervals within a beam, for each beam applied on a service link. Also, the frequency conversion unit 130 of the terrestrial GW station 100 shown in Figures 4 to 6 and the digital processing unit 170 of the terrestrial GW station shown in Figure 7 may constitute a frequency conversion unit that applies a frequency shift to the radio frequencies carrying the signals of each of the multiple telecommunications carriers, and converts the frequencies of the multiple beams applied on a service link into frequencies arranged at predetermined intervals within a beam, for each telecommunications carrier.

[0107] The frequency shift amount for each company and the frequency shift amount required for each beam may be notified appropriately or may be set in advance in the ground station gateway station 100. Furthermore, these shift amounts and frequency multiplexing methods may be shared with the HAPS payload 200 so that the HAPS payload 200 can correctly transmit the frequencies multiplexed on the feeder link over the service link.

[0108] According to the above-described embodiment, the following advantageous effects can be obtained.

[0109] Specifically, the terrestrial gateway station (HAPS gateway) converts multiple signals received from the base station via the O-RAN interface into radio signals using a carrier frequency, applies different frequency shifts to convert them into frequencies located within a predetermined frequency band on the feeder link to the HAPS payload, and transmits the radio signals containing multiple radio frequencies to the HAPS payload.

[0110] This means that conversion to radio frequencies can be performed at the terrestrial gateway station (HAPS GW) rather than at the base station, so that the base station can be connected via an O-RAN standard interface using optical fiber, reducing the number of connecting cables and making them easier to handle.

[0111] In addition, the terrestrial gateway station (HAPS GW) converts a first signal received from the base station via the O-RAN interface into a first radio signal using a carrier frequency, while converting a second signal received from the base station via the O-RAN interface into a second radio signal using a carrier frequency to which a frequency shift has been applied.Then, using an analog frequency converter 130, the frequencies of the first radio signal and the second radio signal are converted into frequencies placed within a predetermined frequency band on the feeder link to the HAPS payload, and the radio signal including multiple radio frequencies is transmitted to the HAPS payload.

[0112] This allows the number of analog frequency converters to be reduced, which in turn allows for reduced power consumption and a more compact device, thereby optimizing system integration.

[0113] Furthermore, the terrestrial gateway station (HAPS GW) converts multiple signals received from the base station via the O-RAN interface into radio frequencies with different frequency shifts applied using a digital processing unit 170, thereby converting the signals into frequencies located within a predetermined frequency band on the feeder link to the HAPS payload, and transmits radio signals including multiple radio frequencies to the HAPS payload.

[0114] This eliminates the need for analog frequency converters and power amplifiers within the RU, reducing power consumption and downsizing the equipment, thereby optimizing system integration.

[0115] (5) Other Embodiments The contents of the present proposal have been described above in accordance with the examples, but it will be obvious to those skilled in the art that the present proposal is not limited to these descriptions and that various modifications and improvements are possible.

[0116] For example, in the above-described embodiment, an example was given of a system in which the service link has four beams and eight carriers multiplexed by two-layer MIMO multiplexing, but other numbers of beams, layers, and carrier multiplexing numbers may also be used.

[0117] In the above-described embodiment, the gNB 50 is a radio base station conforming to 5G, but the radio base station and related network nodes may conform to a system other than 5G (4G, 6G, etc.) as long as they have a similar RU configuration. Also, in the above-described embodiment, functions in the downlink (DL) direction have been mainly described, but the gNB 50, terrestrial GW station 100, and HAPS payload 200 may have functions in the uplink (UL) direction that correspond to those in the DL direction (performing processing opposite to that in the DL direction).

[0118] In the above-described embodiment, the HAPS relay station 200 is assumed to be located in the sky, but the HAPS relay station 200 does not necessarily have to be located in the sky temporarily or permanently. For example, the HAPS relay station 200 may be provided on top of a structure having a certain altitude, or may be mounted on a stationary object in the sky that does not fly in circles.

[0119] Also, in the above description, configure, activate, update, indicate, enable, specify, and select may be interchangeable. Similarly, link, associate, correspond, and map may be interchangeable, and allocate, assign, monitor, and map may be interchangeable.

[0120] Furthermore, specific, dedicated, UE-specific, and UE-dedicated may be interchangeable. Similarly, common, shared, group-common, UE-common, and UE-shared may be interchangeable.

[0121] The block diagrams (e.g., FIGS. 3 and 4 ) used to explain the above-described embodiments show functional blocks. These functional blocks (components) are realized by any combination of hardware and / or software. Furthermore, the method for realizing each functional block is not particularly limited. That is, each functional block may be realized using a single device that is physically or logically coupled, or may be realized using two or more physically or logically separated devices that are connected directly or indirectly (e.g., via wire, wirelessly, etc.) and these multiple devices. The functional block may be realized by combining software with the single device or multiple devices.

[0122] Functions include, but are not limited to, judgment, determination, judgment, calculation, computation, processing, derivation, investigation, search, confirmation, reception, transmission, output, access, resolution, selection, selection, establishment, comparison, assumption, expectation, consideration, broadcasting, notifying, communicating, forwarding, configuring, reconfiguring, allocating, mapping, and assignment. For example, a functional block (component) that performs transmission is called a transmitting unit or transmitter. As mentioned above, there are no particular limitations on how each is implemented.

[0123] Furthermore, the gNB 50, HAPS ground system 100, HAPS relay system 200, and UE 300 (the devices) described above may function as a computer that performs processing of the wireless communication method of the present disclosure. Figure 16 is a diagram showing an example of the hardware configuration of the devices. As shown in Figure 16, the devices may be configured as a computer including a processor 1001, a memory 1002, a storage 1003, a communication device 1004, an input device 1005, an output device 1006, a bus 1007, etc.

[0124] In the following description, the term "apparatus" can be interpreted as a circuit, a device, a unit, etc. The hardware configuration of the apparatus may be configured to include one or more of the apparatuses shown in the drawings, or may be configured to exclude some of the apparatuses.

[0125] Each functional block of the device (FIGS. 3, 4, etc.) is realized by any hardware element of the computer device or a combination of the hardware elements.

[0126] In addition, each function of the device is realized by loading specified software (programs) onto hardware such as processor 1001 and memory 1002, causing processor 1001 to perform calculations, control communication via communication device 1004, and control at least one of reading and writing data in memory 1002 and storage 1003.

[0127] The processor 1001 controls the entire computer by running, for example, an operating system, and may be configured as a central processing unit (CPU) including an interface with peripheral devices, a control unit, an arithmetic unit, and registers.

[0128] The processor 1001 also reads programs (program codes), software modules, data, etc. from at least one of the storage 1003 and the communication device 1004 into the memory 1002 and executes various processes in accordance with these. The programs used are those that cause a computer to execute at least some of the operations described in the above-described embodiments. Furthermore, the various processes described above may be executed by a single processor 1001, or may be executed simultaneously or sequentially by two or more processors 1001. The processor 1001 may be implemented by one or more chips. The programs may be transmitted from a network via a telecommunications line.

[0129] The memory 1002 is a computer-readable recording medium and may be configured by at least one of, for example, a read-only memory (ROM), an erasable programmable ROM (EPROM), an electrically erasable programmable ROM (EEPROM), a random access memory (RAM), etc. The memory 1002 may also be called a register, a cache, a main memory (primary storage device), etc. The memory 1002 may store a program (program code), a software module, etc., capable of executing a method according to an embodiment of the present disclosure.

[0130] Storage 1003 is a computer-readable recording medium, and may be, for example, at least one of an optical disk such as a Compact Disc ROM (CD-ROM), a hard disk drive, a flexible disk, a magneto-optical disk (e.g., a compact disk, a digital versatile disk, a Blu-ray disc), a smart card, a flash memory (e.g., a card, a stick, a key drive), a floppy disk, a magnetic strip, etc. Storage 1003 may also be referred to as an auxiliary storage device. The above-mentioned recording medium may be, for example, a database, a server, or other suitable medium including at least one of memory 1002 and storage 1003.

[0131] The communication device 1004 is hardware (transmission / reception device) for communicating between computers via at least one of a wired network and a wireless network, and is also called, for example, a network device, a network controller, a network card, or a communication module.

[0132] The communication device 1004 may be configured to include a high-frequency switch, a duplexer, a filter, a frequency synthesizer, etc. to realize, for example, at least one of Frequency Division Duplex (FDD) and Time Division Duplex (TDD).

[0133] The input device 1005 is an input device (e.g., a keyboard, a mouse, a microphone, a switch, a button, a sensor, etc.) that receives input from the outside. The output device 1006 is an output device (e.g., a display, a speaker, an LED lamp, etc.) that outputs to the outside. Note that the input device 1005 and the output device 1006 may be integrated into one device (e.g., a touch panel).

[0134] Furthermore, each device such as the processor 1001 and the memory 1002 is connected to a bus 1007 for communicating information. The bus 1007 may be configured using a single bus, or may be configured using different buses between each device.

[0135] Furthermore, the device may be configured to include hardware such as a microprocessor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a programmable logic device (PLD), or a field programmable gate array (FPGA), and some or all of the functional blocks may be realized by the hardware. For example, the processor 1001 may be implemented using at least one of these pieces of hardware.

[0136] Furthermore, the notification of information is not limited to the aspects / embodiments described in the present disclosure, and may be performed using other methods. For example, the notification of information may be performed by physical layer signaling (e.g., Downlink Control Information (DCI), Uplink Control Information (UCI)), higher layer signaling (e.g., RRC signaling, Medium Access Control (MAC) signaling, broadcast information (Master Information Block (MIB), System Information Block (SIB))), other signals, or a combination thereof. Furthermore, the RRC signaling may be referred to as an RRC message, and may be, for example, an RRC Connection Setup message, an RRC Connection Reconfiguration message, or the like.

[0137] Each aspect / embodiment described in the present disclosure may be applied to at least one of a system using Long Term Evolution (LTE), LTE-Advanced (LTE-A), SUPER 3G, IMT-Advanced, a 4th generation mobile communication system (4G), a 5th generation mobile communication system (5G), a 6th generation mobile communication system (6G), an xth generation mobile communication system (xG) (where x is, for example, an integer or a decimal), Future Radio Access (FRA), New Radio (NR), W-CDMA (registered trademark), GSM (registered trademark), CDMA2000, Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi (registered trademark)), IEEE 802.16 (WiMAX (registered trademark)), IEEE 802.20, Ultra-WideBand (UWB), Bluetooth (registered trademark), or other suitable system, and a next-generation system extended based on these. Furthermore, a combination of multiple systems (e.g., a combination of at least one of LTE and LTE-A with 5G) may also be applied.

[0138] The order of the procedures, sequences, flowcharts, etc. of each aspect / embodiment described in this disclosure may be changed unless it is consistent. For example, the methods described in this disclosure present elements of various steps using an example order, and are not limited to the particular order presented.

[0139] In the present disclosure, a specific operation described as being performed by a base station may also be performed by its upper node in some cases. In a network consisting of one or more network nodes having a base station, it is clear that various operations performed for communication with a terminal may be performed by at least one of the base station and another network node other than the base station (e.g., MME or S-GW, etc., but are not limited to these). Although the above example illustrates a case where there is one other network node other than the base station, a combination of multiple other network nodes (e.g., MME and S-GW) may also be used.

[0140] Information, signals (information, etc.) may be output from a higher layer (or a lower layer) to a lower layer (or a higher layer), or may be input and output via multiple network nodes.

[0141] The input and output information may be stored in a specific location (for example, a memory) or may be managed using a management table. The input and output information may be overwritten, updated, or added to. The output information may be deleted. The input information may be transmitted to another device.

[0142] The determination may be made based on a value represented by one bit (0 or 1), a Boolean value (true or false), or a numerical comparison (e.g., comparison with a predetermined value).

[0143] The aspects / embodiments described in this disclosure may be used alone, in combination, or switched depending on the implementation. Notification of predetermined information (e.g., notification that "X is true") is not limited to explicit notification, but may be implicit (e.g., not notifying the predetermined information).

[0144] Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executable files, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise.

[0145] Software, instructions, information, etc. may also be transmitted or received over a transmission medium. For example, if software is transmitted from a website, server, or other remote source using wired technologies (such as coaxial cable, fiber optic cable, twisted pair, Digital Subscriber Line (DSL)), and / or wireless technologies (such as infrared, microwave), then these wired and / or wireless technologies are included within the definition of transmission media.

[0146] The information, signals, etc. described in this disclosure may be represented using any of a variety of different technologies. For example, data, instructions, commands, information, signals, bits, symbols, chips, etc. that may be referred to throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or magnetic particles, optical fields or photons, or any combination thereof.

[0147] Note that terms described in this disclosure and terms necessary for understanding this disclosure may be replaced with terms having the same or similar meanings. For example, at least one of a channel and a symbol may be a signal (signaling). Furthermore, a signal may be a message. Furthermore, a component carrier (CC) may be called a carrier frequency, a cell, a frequency carrier, etc.

[0148] As used in this disclosure, the terms "system" and "network" are used interchangeably.

[0149] Furthermore, the information, parameters, etc. described in the present disclosure may be expressed using absolute values, may be expressed using relative values ​​from a predetermined value, or may be expressed using other corresponding information. For example, a radio resource may be indicated by an index.

[0150] The names used for the above-described parameters are not intended to be limiting in any way. Furthermore, the mathematical expressions using these parameters may differ from those explicitly disclosed in this disclosure. The various channels (e.g., PUCCH, PDCCH, etc.) and information elements may be identified by any suitable names, and therefore the various names assigned to these various channels and information elements are not intended to be limiting in any way.

[0151] In this disclosure, terms such as "base station (BS)," "radio base station," "fixed station," "NodeB," "eNodeB (eNB)," "gNodeB (gNB)," "access point," "transmission point," "reception point," "transmission / reception point," "cell," "sector," "cell group," "carrier," and "component carrier" may be used interchangeably. Base stations may also be referred to by terms such as macrocell, small cell, femtocell, and picocell.

[0152] A base station can accommodate one or more (e.g., three) cells (also called sectors). When a base station accommodates multiple cells, the overall coverage area of ​​the base station can be divided into multiple smaller areas, and each smaller area can be provided with communication services by a base station subsystem (e.g., a small indoor base station (Remote Radio Head: RRH)).

[0153] The terms "cell" or "sector" refer to part or all of the coverage area of ​​a base station and / or base station subsystem that provides communication services within that coverage area.

[0154] In the present disclosure, the base station transmitting information to a terminal may be interpreted as the base station instructing the terminal to control or operate based on the information.

[0155] In this disclosure, the terms "Mobile Station (MS)," "user terminal," "User Equipment (UE)," "terminal," etc. may be used interchangeably.

[0156] A mobile station may also be referred to by those skilled in the art as a subscriber station, mobile unit, subscriber unit, wireless unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile subscriber station, access terminal, mobile terminal, wireless terminal, remote terminal, handset, user agent, mobile client, client, or some other suitable terminology.

[0157] At least one of the base station and the mobile station may be referred to as a transmitting device, a receiving device, a communication device, etc. At least one of the base station and the mobile station may be a device mounted on a mobile object, the mobile object itself, etc. The mobile object may be a vehicle (e.g., a car, an airplane, etc.), an unmanned mobile object (e.g., a drone, an autonomous vehicle, etc.), or a robot (manned or unmanned). At least one of the base station and the mobile station may also include devices that do not necessarily move during communication operations. For example, at least one of the base station and the mobile station may be an Internet of Things (IoT) device such as a sensor.

[0158] Furthermore, a base station in the present disclosure may be read as a mobile station (user terminal, the same applies hereinafter). For example, the aspects / embodiments of the present disclosure may be applied to a configuration in which communication between a base station and a mobile station is replaced with communication between multiple mobile stations (which may be called, for example, Device-to-Device (D2D) or Vehicle-to-Everything (V2X)). In this case, the mobile station may be configured to have the functions of a base station. Furthermore, terms such as "uplink" and "downlink" may be read as terms corresponding to terminal-to-terminal communication (for example, "side"). For example, terms such as an uplink channel and a downlink channel may be read as a side channel (or sidelink).

[0159] Similarly, a mobile station in the present disclosure may be interpreted as a base station, in which case the base station may have the functions of a mobile station.

[0160] A radio frame may be composed of one or more frames in the time domain. Each of the one or more frames in the time domain may be called a subframe. A subframe may further be composed of one or more slots in the time domain. A subframe may have a fixed time length (e.g., 1 ms) that is independent of numerology.

[0161] Numerology may be communication parameters that apply to the transmission and / or reception of a signal or channel, such as subcarrier spacing (SCS), bandwidth, symbol length, cyclic prefix length, transmission time interval (TTI), number of symbols per TTI, radio frame structure, specific filtering operations performed by the transceiver in the frequency domain, and specific windowing operations performed by the transceiver in the time domain.

[0162] A slot may consist of one or more symbols in the time domain (such as an Orthogonal Frequency Division Multiplexing (OFDM) symbol, a Single Carrier Frequency Division Multiple Access (SC-FDMA) symbol, etc.) A slot may be a numerology-based time unit.

[0163] A slot may include multiple minislots. Each minislot may consist of one or more symbols in the time domain. A minislot may also be called a subslot. A minislot may consist of fewer symbols than a slot. A PDSCH (or PUSCH) transmitted in a time unit larger than a minislot may be called PDSCH (or PUSCH) mapping type A. A PDSCH (or PUSCH) transmitted using a minislot may be called PDSCH (or PUSCH) mapping type B.

[0164] The radio frame, subframe, slot, minislot, and symbol all represent time units for transmitting signals, and may be referred to by other names corresponding to the radio frame, subframe, slot, minislot, and symbol.

[0165] For example, one subframe may be referred to as a transmission time interval (TTI), multiple consecutive subframes may be referred to as a TTI, or one slot or one minislot may be referred to as a TTI. That is, at least one of the subframe and the TTI may be a subframe (1 ms) in existing LTE, a period shorter than 1 ms (e.g., 1-13 symbols), or a period longer than 1 ms. Note that the unit representing the TTI may be called a slot, minislot, etc., instead of a subframe.

[0166] Here, TTI refers to, for example, the smallest time unit for scheduling in wireless communication. For example, in an LTE system, a base station schedules each user terminal to allocate radio resources (such as frequency bandwidth and transmission power that can be used by each user terminal) in TTI units. Note that the definition of TTI is not limited to this.

[0167] The TTI may be a transmission time unit for a channel-encoded data packet (transport block), a code block, a code word, etc., or may be a processing unit for scheduling, link adaptation, etc. When a TTI is given, the time interval (e.g., the number of symbols) to which a transport block, a code block, a code word, etc. is actually mapped may be shorter than the TTI.

[0168] In addition, when one slot or one minislot is called a TTI, one or more TTIs (i.e., one or more slots or one or more minislots) may be the minimum time unit for scheduling, and the number of slots (minislots) constituting the minimum time unit for scheduling may be controlled.

[0169] A TTI having a time length of 1 ms may be referred to as a regular TTI (TTI in LTE Rel. 8-12), normal TTI, long TTI, regular subframe, normal subframe, long subframe, slot, etc. A TTI shorter than a regular TTI may be referred to as a shortened TTI, short TTI, partial or fractional TTI, shortened subframe, short subframe, minislot, subslot, slot, etc.

[0170] In addition, a long TTI (e.g., a normal TTI, a subframe, etc.) may be interpreted as a TTI having a time length of more than 1 ms, and a short TTI (e.g., a shortened TTI, etc.) may be interpreted as a TTI having a TTI length shorter than the TTI length of a long TTI and equal to or greater than 1 ms.

[0171] A resource block (RB) is a resource allocation unit in the time domain and the frequency domain, and may include one or more consecutive subcarriers in the frequency domain. The number of subcarriers included in an RB may be the same regardless of numerology, for example, 12. The number of subcarriers included in an RB may be determined based on numerology.

[0172] The time domain of an RB may include one or more symbols and may have a length of one slot, one minislot, one subframe, or one TTI, each of which may consist of one or more resource blocks.

[0173] Note that one or more RBs may also be called a physical resource block (PRB), a sub-carrier group (SCG), a resource element group (REG), a PRB pair, an RB pair, etc.

[0174] Furthermore, a resource block may be composed of one or more resource elements (REs). For example, one RE may be a radio resource region of one subcarrier and one symbol.

[0175] A Bandwidth Part (BWP) (which may also be referred to as a fractional bandwidth) may represent a subset of contiguous common resource blocks (RBs) for a given numerology on a given carrier, where the common RBs may be identified by their index relative to a common reference point of the carrier. PRBs may be defined in a given BWP and numbered within that BWP.

[0176] The BWP may include a BWP for UL (UL BWP) and a BWP for DL ​​(DL BWP). One or more BWPs may be configured for a UE within one carrier.

[0177] At least one of the configured BWPs may be active, and the UE may not expect to transmit or receive a given signal / channel outside the active BWP. Note that the terms "cell," "carrier," etc. in this disclosure may be read as "BWP."

[0178] The above-described structures of the radio frame, subframe, slot, minislot, and symbol are merely examples. For example, the number of subframes included in a radio frame, the number of slots per subframe or radio frame, the number of minislots included in a slot, the number of symbols and RBs included in a slot or minislot, the number of subcarriers included in an RB, the number of symbols in a TTI, the symbol length, the cyclic prefix (CP) length, and other configurations may be changed in various ways.

[0179] The terms "connected," "coupled," or any variation thereof, refer to any direct or indirect connection or coupling between two or more elements, and may include the presence of one or more intermediate elements between two elements that are "connected" or "coupled" to each other. The coupling or connection between elements may be physical, logical, or a combination thereof. For example, "connected" may be read as "access." As used in this disclosure, two elements may be considered to be "connected" or "coupled" to each other using one or more wires, cables, and / or printed electrical connections, as well as electromagnetic energy having wavelengths in the radio frequency range, microwave range, and optical (both visible and invisible) range, as some non-limiting and non-exhaustive examples.

[0180] The reference signal may also be abbreviated as Reference Signal (RS) and may be called a pilot depending on the applicable standard.

[0181] As used in this disclosure, the phrase "based on" does not mean "based only on," unless expressly stated otherwise. In other words, the phrase "based on" means both "based only on" and "based at least on."

[0182] The "means" in the configuration of each of the above devices may be replaced with "part," "circuit," "device," etc.

[0183] As used in this disclosure, any reference to an element using a designation such as "first," "second," etc. does not generally limit the quantity or order of those elements. These designations may be used in this disclosure as a convenient method of distinguishing between two or more elements. Thus, a reference to a first and a second element does not imply that only two elements may be employed therein or that the first element must precede the second element in some way.

[0184] When the terms "include," "including," and variations thereof are used in this disclosure, these terms are intended to be inclusive, similar to the term "comprising." Furthermore, when the term "or" is used in this disclosure, it is not intended to be an exclusive or.

[0185] In this disclosure, where articles are added by translation, such as a, an, and the in English, the disclosure may include that the nouns following these articles are in the plural form.

[0186] As used in this disclosure, the terms "determining" and "determining" may encompass a wide variety of actions. "Determining" and "determining" may include, for example, judging, calculating, computing, processing, deriving, investigating, looking up, searching, inquiring (e.g., searching in a table, database, or other data structure), ascertaining, and the like. "Determining" and "determining" may also include receiving (e.g., receiving information), transmitting (e.g., sending information), input, output, accessing (e.g., accessing data in memory), and the like. Furthermore, "judgment" and "decision" can include regarding resolving, selecting, choosing, establishing, comparing, etc. as having been "judged" or "decided." In other words, "judgment" and "decision" can include regarding some action as having been "judged" or "decided." Furthermore, "judgment (decision)" can be interpreted as "assuming," "expecting," "considering," etc.

[0187] In the present disclosure, the term "A and B are different" may mean "A and B are different from each other." The term may also mean "A and B are each different from C." Terms such as "separate" and "coupled" may also be interpreted in the same way as "different."

[0188] Although the present disclosure has been described in detail above, it is clear to those skilled in the art that the present disclosure is not limited to the embodiments described herein. The present disclosure can be implemented in modified and altered forms without departing from the spirit and scope of the present disclosure as defined by the claims. Therefore, the description of the present disclosure is intended to be illustrative and does not have any limiting meaning on the present disclosure.

[0189] 10 Wireless communication system 50 Wireless base station 51 Wireless unit 100 Terrestrial GW device 110 Wireless unit 120 Duplexer 130 Frequency conversion unit 140 Multiplexing and demultiplexing unit 150 Wireless transmission and reception unit 160 Multiplexing and demultiplexing unit 170 Digital processing unit 200 Relay station device 300 UE 1001 Processor 1002 Memory 1003 Storage 1004 Communication device 1005 Input device 1006 Output device 1007 Bus

Claims

a radio unit that converts a plurality of baseband signals received from a base station of a terrestrial network via an optical fiber into radio signals using a carrier frequency; a frequency conversion unit that applies different frequency shifts to the frequencies of the radio signals to convert them into frequencies that are located within a predetermined frequency band on a link to a relay station device of a non-terrestrial network; a transmitter that transmits, to the relay station device, a radio signal including a plurality of radio frequencies arranged within the predetermined frequency band; A ground station device comprising: 　 a first radio unit that converts a first baseband signal received from a base station of a terrestrial network via an optical fiber into a first radio signal using a carrier frequency; a second radio unit that converts a second baseband signal received from the base station into a second radio signal using a carrier frequency to which a frequency shift has been applied; a frequency conversion unit that converts the frequencies of the first radio signal and the second radio signal into frequencies that are placed within a predetermined frequency band on a link to a relay station device of a non-terrestrial network; a transmitter that transmits, to the relay station device, a radio signal including a plurality of radio frequencies arranged within the predetermined frequency band; A ground station device comprising: 　 a radio processing unit that converts a plurality of baseband signals received from a base station of a terrestrial network via an optical fiber into radio frequencies to which different frequency shifts are applied, thereby converting the signals into frequencies that are located within a predetermined frequency band on a link to a relay station device of a non-terrestrial network; a transmitter that transmits, to the relay station device, a radio signal including a plurality of radio frequencies arranged within the predetermined frequency band; A ground station device comprising:

4. The earth station device according to claim 1, wherein the signal received from the base station is a bit string of a digitally modulated signal in the frequency domain. 　 converting a plurality of baseband signals received via optical fiber from a base station of a terrestrial network into radio signals using a carrier frequency; applying a different frequency shift to the frequency of each of the radio signals to convert them into frequencies located within a predetermined frequency band on a link to a relay station device of a non-terrestrial network; transmitting a radio signal including a plurality of radio frequencies arranged within the predetermined frequency band to the relay station device; A radio communication method for a ground station device comprising: 　 converting a first baseband signal received via an optical fiber from a base station of a terrestrial network into a first radio signal using a carrier frequency; converting a second baseband signal received from the base station into a second radio signal using a carrier frequency to which a frequency shift has been applied; converting the frequencies of the first radio signal and the second radio signal to frequencies located within a predetermined frequency band on a link to a relay station device of a non-terrestrial network; transmitting a radio signal including a plurality of radio frequencies arranged within the predetermined frequency band to the relay station device; A radio communication method for a ground station device comprising: 　 a step of converting a plurality of baseband signals received from a base station of a terrestrial network via an optical fiber into radio frequencies to which different frequency shifts are applied, thereby converting the signals into frequencies located within a predetermined frequency band on a link to a relay station device of a non-terrestrial network; transmitting a radio signal including a plurality of radio frequencies arranged within the predetermined frequency band to the relay station device; A radio communication method for a ground station device comprising: 　 A wireless communication system including a base station of a terrestrial network and a terrestrial station device connected to the base station by an optical fiber, The base station a transmitter that transmits a plurality of baseband signals via the optical fiber; The ground station device a radio unit that converts a plurality of baseband signals received from the base station via the optical fiber into radio signals using a carrier frequency; a frequency conversion unit that applies different frequency shifts to the frequencies of the radio signals to convert them into frequencies that are located within a predetermined frequency band on a link to a relay station device of a non-terrestrial network; a transmitter that transmits, to the relay station device, a radio signal including a plurality of radio frequencies arranged within the predetermined frequency band; A wireless communication system comprising:

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