Aerial node and ground station equipment

Abstract

This aerial node comprises a communication unit that communicates with a ground terminal by time division duplex. The aerial node also comprises a control unit that performs control such that the timing of an uplink slot in the time-division duplex does not match the timing of an uplink slot in time division duplex of another aerial node, and the timing of a downlink slot in the time division duplex does not match the timing of a downlink slot in time division duplex of the other aerial node.

Description

Aerial Node and Ground Station Device

[0001] The present disclosure relates to an aerial node and a ground station device that constitute a non-terrestrial network.

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

[0003] Introduction of a non-terrestrial network (NTN: Non-Terrestrial Network) has been under consideration to realize provision of various services to areas that cannot be covered by mobile communication networks based on terrestrial networks (PLMN: Public Land Mobile Network). Components of NTN include Geostationary Orbit satellites (GEO), Low Earth Orbit satellites (LEO), and High-Altitude Platform Station (HAPS). (Non-Patent Document 1)

[0004] For example, for HAPS, although a frequency band for Frequency Division Duplex (FDD) has already been specified as an available frequency band for communication links (service links) with ground terminals, it was determined at WRC (World Radiocommunication Conference)-23 that 2010-2025 MHz (Band34 / n34) can be used as a frequency band for Time Division Duplex (TDD). (Non-Patent Document 2)

[0005] Hinata Ohara, et al., “Development of a 38GHz Band Wireless Communication System Linked with a 5G Network Using a High Altitude Platform (HAPS) – Novel HAPS System Configuration Utilizing Terrestrial Network Facilities,” IEICE Research Institute, March 2022; WRC-23 Final Acts, ITU Publications, 2023.

[0006] When applying TDD to a terrestrial network system, interference between base stations and between terminals is generally suppressed by synchronizing TDD between adjacent base stations.

[0007] However, when the TDD method is applied to a non-terrestrial network system like HAPS, interference between HAPS nodes is usually small because they are tens of kilometers apart. Also, because the terrestrial area covered by HAPS nodes is large, the locations of simultaneously scheduled terminals are dispersed, which is thought to reduce the opportunities for interference between terminals.

[0008] On the other hand, synchronizing TDD (Technical Deposition) beams results in inter-beam interference, requiring advanced beam interference control techniques such as null forming. However, the requirements for mounting these beams on HAPS (High-Area Spatial Systems) are very strict, and it may not be possible to implement such advanced control techniques. Therefore, the challenge lies in how to suppress inter-beam interference.

[0009] Therefore, the following disclosure is made in light of these circumstances and aims to provide airborne nodes and ground station equipment that can effectively suppress inter-beam interference even when TDD is applied to service links of non-terrestrial networks.

[0010] One aspect of the present disclosure is an airborne node (100) comprising a communication unit (140) that communicates with a ground terminal using time division duplexing, and a control unit (150) that controls the timing of the uplink slot in the time division duplexing so as not to match the timing of the uplink slot in the time division duplexing of other airborne nodes, and the timing of the downlink slot in the time division duplexing so as not to match the timing of the downlink slot in the time division duplexing of other airborne nodes.

[0011] One aspect of the present disclosure is an aerial node (100) comprising a communication unit (140) that provides communications from different operators for each beam to a ground terminal in time-division duplex, and a control unit (150) that controls the timing of the uplink slots in the beam of the first operator so as not to coincide with the timing of the uplink slots in the beam of the second operator, and the timing of the downlink slots in the beam of the first operator so as not to coincide with the timing of the downlink slots in the beam of the second operator.

[0012] One aspect of the present disclosure is a ground station device (300 or 400) comprising: a transmitting unit (310 or 410) that transmits a control signal to a first airborne node that communicates with a ground terminal in time division duplexing, instructing an allocation pattern for uplink and downlink slots; and a control unit (330 or 440) that generates the allocation pattern such that the timing of the uplink slot of the first airborne node does not match the timing of the uplink slot in time division duplexing of the second airborne node, and the timing of the downlink slot of the first airborne node does not match the timing of the downlink slot in time division duplexing of the second airborne node.

[0013] Figure 1 is a diagram showing an example of the overall schematic configuration of the wireless communication system 10 according to this embodiment. Figure 2 is a functional block configuration diagram of an airborne node. Figure 3 is a functional block configuration diagram of a base station. Figure 4 is a functional block configuration diagram of a ground GW station. Figure 5 is a diagram showing interference when TDD is applied to the service link SL. Figure 6 is a diagram showing an example of an inverted synchronization pattern of TDD in the embodiment. Figure 7 is a diagram illustrating propagation delay. Figure 8 is a diagram illustrating the interference suppression conditions from airborne node 1 to terminal B in inverted synchronization pattern 1. Figure 9 is a diagram illustrating the interference suppression conditions from airborne node 2 to terminal A in inverted synchronization pattern 1. Figure 10 is a diagram illustrating the interference suppression conditions from terminal A to airborne node 2 in inverted synchronization pattern 1. Figure 11 is a diagram illustrating the interference suppression conditions from terminal B to airborne node 1 in inverted synchronization pattern 1. Figure 12 is a diagram illustrating the interference suppression conditions from airborne node 1 to terminal B in inverted synchronization pattern 2. Figure 13 is a diagram illustrating the interference suppression conditions from airborne node 2 to terminal A in inverted synchronization pattern 2. Figure 14 illustrates the interference suppression conditions from terminal A to airborne node 2 in inverted synchronization pattern 2. Figure 15 illustrates the interference suppression conditions from terminal B to airborne node 1 in inverted synchronization pattern 2. Figure 16 shows the swapping of DU patterns. Figure 17 shows an example of applying frequency division and inverted synchronization simultaneously. Figure 18 shows an example of multiple telecommunications service providers sharing the same airborne node. Figure 19 shows an example of applying inverted synchronization in multiple beams. Figure 20 shows an example of the hardware configuration of an airborne node, a ground GW station, and a base station.

[0014] This embodiment will be described below with reference to the drawings. Note that identical or similar reference numerals are used to denote the same function or configuration, and their descriptions will be omitted as appropriate.

[0015] (1) Example of overall schematic configuration of the wireless communication system Figure 1 shows an example of the overall schematic configuration of the wireless communication system 10 according to this embodiment. As shown in Figure 1, the wireless communication system 10 includes an airborne node 100, a terminal (UE: User Equipment) 200, a base station 300, a ground GW station 400, and a satellite 500.

[0016] The aerial node 100 may be, for example, a HAPS. A HAPS can be permanently stationed in a fixed location in the stratosphere at an altitude of approximately 20 km and can form a coverage area on the ground with a radius of approximately 50 to 100 km. Specifically, the aerial node 100 forms multiple cell beams on the ground by controlling its antenna. The aerial node 100 may be a regenerative relay type HAPS equipped with base station (eNB or gNB) functionality. In this case, not all base station functions need to be installed in the HAPS; some functions may be located on the ground. Also, the aerial node 100 may be a non-regenerative relay type, such as a penetrating relay type (pentpipe) HAPS. Note that the aerial node 100 is not limited to a HAPS as long as it is an aerial node located within a propagation distance that allows it to communicate with the ground UE200 using TDD.

[0017] The ground GW station 400 is a GW (Gateway) device on the ground, and may be, for example, a satellite GW earth station. The satellite 500 may be, for example, a geostationary satellite GEO in orbit at an altitude of approximately 36,000 km, or a low Earth orbit satellite LEO in orbit at an altitude of several hundred to approximately 2,000 km.

[0018] Figure 1 shows an example where the feeder link FL, which is the communication link between the aerial node 100 and the ground station 400, uses a backhaul link via satellite 500. An advantage of using satellite 500 is that the installation location of the ground GW station 400 does not need to be within the HAPS coverage area. However, the feeder link FL between the aerial node 100 and the ground station 400 may also be directly connected without going through satellite 500. For example, high-frequency bands such as millimeter waves may be used in the feeder link FL, and signals from multiple cells and beams may be frequency-multiplexed and transmitted over a wide bandwidth.

[0019] Base station 300 may be, for example, a 5G (NR) compliant wireless base station gNB (gNode B). Base station 300 performs 5G (NR) compliant wireless communication with UE200 via a ground GW station 400 and an airborne node 100. Base station 300 may be connected to a 5G (NR) compliant core network (5GC) via a backhaul (link). In addition, base station 300 and UE200 may support not only 5G but also other mobile communication systems, such as 4G / LTE (Long Term Evolution), Beyond 5G, 5G Evolution, or 6G.

[0020] The service link SL, which is the communication link between the airborne node 100 and the ground UE200, may apply TDD in the 2GHz band, specifically the 2010–2025MHz frequency band (Band34 / n34). Unlike Band1 / n1, which is divided into 20MHz bands by multiple operators, the 2010–2025MHz frequency band (Band34 / n34) is narrow at 15MHz, and therefore needs to be effectively utilized by multiple operators or by different airborne nodes 100 of the same operator.

[0021] In this way, by configuring the wireless communication system 10 by combining a regenerative relay payload and a TDD bandwidth, the communication distance (latency) from the base station 300 to the UE200 can be shortened, and longer-distance communication becomes possible with the same guard time for TDD. Furthermore, even when TDD is applied to the service link SL, FDD or satellite communication can also be applied to the feeder link FL, enabling flexible operation.

[0022] (2) Functional Block Configuration of the Wireless Communication System Next, the functional block configuration of the wireless communication system 10 will be described using Figures 2 to 4. Note that each figure is an example of the main functional blocks related to the description of the embodiment, and other functional blocks may be present. Also, each figure shows the functional block configuration, and for the hardware configuration, please refer to Figure 20.

[0023] (2.1) Figure 2 of the aerial node diagram is a functional block diagram of the aerial node 100. In Figure 2, the aerial node 100 includes an Aircraft systems unit 110 and a payload 120. The Aircraft systems unit 110 controls various functions related to the flight system. The payload 120 includes an FL communication unit 130, an SL communication unit 140, a reverse synchronous control unit 150, and a control unit 160. The reverse synchronous control unit 150 and the control unit 160 correspond to base station functions.

[0024] The FL communication unit 130 transmits and receives various signals with the ground GW station 400 via the feeder link FL.

[0025] The SL communication unit 140 transmits and receives various signals with the ground UE200 via the service link SL. In this embodiment, TDD is applied in the frequency band of 2010 to 2025 MHz (Band 34 / n34). Between airborne nodes 100 whose ground coverage areas overlap, a 15 MHz bandwidth is divided and used. Between airborne nodes 100 whose ground coverage areas are adjacent, the inverted synchronization method described later is applied to effectively utilize the 15 MHz bandwidth for each.

[0026] The SL communication unit 140 in this embodiment may be configured as a communication unit that communicates with a ground terminal using time-division duplexing. Alternatively, the SL communication unit 140 in this embodiment may be configured as a communication unit that provides communications from different carriers to the ground terminal using time-division duplexing for each beam.

[0027] The inversion synchronization control unit 150 controls the inversion synchronization method, described later, between adjacent air nodes 100 and the TDD of the service link SL. For example, in this embodiment, it may perform processes to determine whether or not to apply inversion synchronization, and if inversion synchronization is applied, to set and adjust the timing shift amount, described later.

[0028] The inverted synchronous control unit 150 of the embodiment may be configured to control the timing of the uplink slot in time division duplexing so as not to match the timing of the uplink slot in time division duplexing of other air nodes. Furthermore, the inverted synchronous control unit 150 of the embodiment may be configured to control the timing of the downlink slot in time division duplexing so as not to match the timing of the downlink slot in time division duplexing of other air nodes.

[0029] Here, "the timing of the up slots does not match" can be understood as meaning that the up slots do not overlap in time. Similarly, "the timing of the down slots does not match" can be understood as meaning that the down slots do not overlap in time. Specifically, as will be explained later, this can be understood as an example of the inverted synchronization pattern shown in Figure 6.

[0030] Furthermore, the inverting synchronous control unit 150 of the embodiment may be configured to control the timing of the up slots in the beam of the first operator so as not to match the timing of the up slots in the beam of the second operator. Also, the inverting synchronous control unit 150 of the embodiment may be configured to control the timing of the down slots in the beam of the first operator so as not to match the timing of the down slots in the beam of the second operator.

[0031] The control unit 160 controls each functional block that constitutes the payload 120. In this embodiment, it receives a control signal for inverted synchronization via the FL communication unit 130 and controls the inverted synchronization control unit 150.

[0032] (2.2) Base station Figure 3 is a functional block diagram of base station 300. In Figure 3, base station 300 comprises a ground station communication unit 310, a core network communication unit 320, an inverting synchronous control unit 330, and a control unit 340.

[0033] The ground station communication unit 310 transmits and receives various signals with the ground gateway station 400. From the perspective of utilizing the existing network equipment of the communication service provider, the connection between the base station 300 and the ground gateway station can be made using RF splitting, where the input / output interface is RF signals, or fronthaul splitting, where optical fiber is used for the fronthaul.

[0034] The ground station communication unit 310 of this embodiment may be configured as a transmitting unit that transmits control signals to a first airborne node that communicates with a ground terminal using time-division duplexing, instructing it on the allocation pattern of uplink and downlink slots.

[0035] The core network communication unit 320 transmits and receives various signals to and from the core network.

[0036] The inversion synchronization control unit 330 controls the inversion synchronization for the airborne nodes 100. In this embodiment, the communication service provider instructs each of the multiple airborne nodes 100 to use control signals to determine whether or not to apply inversion synchronization, and the amount of timing shift if inversion synchronization is applied.

[0037] The inverted synchronous control unit 330 of the embodiment may be configured to generate an allocation pattern in which the timing of the uplink slot of the first air node does not match the timing of the uplink slot in the time-division duplex of the second air node. Alternatively, the inverted synchronous control unit 330 of the embodiment may be configured to generate an allocation pattern in which the timing of the downlink slot of the first air node does not match the timing of the downlink slot in the time-division duplex of the second air node.

[0038] The control unit 340 controls each functional block that makes up the base station 300.

[0039] (2.3) Figure 4 of the Ground GW Station is a functional block diagram of the Ground GW Station 400. In Figure 4, the Ground GW Station 400 includes the FL communication unit 410, the base station communication unit 420, the inverting synchronous control unit 430, and the control unit 440.

[0040] The FL communication unit 410 transmits and receives various signals to and from the satellite 500. If it is directly connected to the HAPS 100 without going through the satellite 500, it may transmit and receive various signals to and from the HAPS 100.

[0041] The FL communication unit 410 according to the embodiment may constitute a transmitting unit that transmits a control signal instructing an allocation pattern of uplink slots and downlink slots to a first aerial node that performs communication with a ground terminal by time division duplex.

[0042] The base station communication unit 420 transmits and receives various signals to and from the base station 300.

[0043] The inverted synchronization control unit 430 controls inverted synchronization for the aerial node 100 when a plurality of communication service providers (Company A, Company B and Company C) share the same aerial node 100. In the embodiment, the shared aerial node 100 is instructed by using a control signal about whether or not to apply inverted synchronization between beams that provide communication services of each communication service provider, the amount of timing shift when inverted synchronization is applied, and the like.

[0044] The inverted synchronization control unit 430 according to the embodiment may constitute a control unit that generates an allocation pattern in which the timing of uplink slots of the first aerial node does not coincide with the timing of uplink slots in time division duplex of the second aerial node. Further, the inverted synchronization control unit 430 according to the embodiment may constitute a control unit that generates an allocation pattern in which the timing of downlink slots of the first aerial node does not coincide with the timing of downlink slots in time division duplex of the second aerial node.

[0045] The control unit 440 controls each functional block constituting the ground GW station 400.

[0046] (3) Operation of wireless communication system Next, the operation of the wireless communication system 10 will be described. (3.1) Background When TDD is applied to a non-terrestrial network system, unlike terrestrial network systems, it is considered that countermeasures against inter-beam interference are more important than inter-node interference and inter-terminal interference. However, the mounting requirements (weight, power consumption, size) for HAPS are very strict, and there is a possibility that advanced control technologies such as null forming for suppressing inter-beam interference cannot be implemented. Therefore, how to suppress inter-beam interference becomes an issue.

[0047] The technical problems to be achieved in the present disclosure are not limited to the technical problems mentioned above, and other technical problems not mentioned above will be clearly understood from the description of the present specification by a person having ordinary knowledge in the technical field to which the present disclosure pertains.

[0048] (3.2) Inverted synchronization scheme of TDD FIG. 5 is a diagram illustrating interference when TDD is applied to a service link SL. In FIG. 5, a terminal A is located in the ground coverage area of an aerial node 1, and a terminal B is located in the ground coverage area of an aerial node 2.

[0049] When a synchronization scheme that synchronizes respective uplink slots and synchronizes respective downlink slots between the aerial node 1 and the aerial node 2 is applied, inter-beam interference becomes a problem as described below.

[0050] i) Inter-beam interference between downlink communications The downlink communication received by terminal A from aerial node 1 is subject to inter-beam interference from the downlink communication transmitted by aerial node 2. Similarly, the downlink communication received by terminal B from aerial node 2 is subject to inter-beam interference from the downlink communication transmitted by aerial node 1. Since non-terrestrial systems have wider coverage than terrestrial systems, off-axis radiation also tends to be larger.

[0051] ii) Inter-beam interference between uplink communications Conversely, the uplink communication received by aerial node 1 from terminal A is subjected to inter-beam interference from the uplink communication transmitted by terminal B. Similarly, the uplink communication received by aerial node 2 from terminal B is subjected to inter-beam interference from the uplink communication transmitted by terminal A. Clutter loss upwards is small, but the interference waves from the Line of Sight (LOS) accumulate, which can result in significant interference.

[0052] In this embodiment, an inversion-synchronous method is applied in TDD to suppress inter-beam interference.

[0053] Figure 6 shows an example of the inverted synchronization method in this embodiment. In this example, one frame consists of 10 subframes. The subcarrier spacing (SCS) is 15 kHz, and one frame is 10 ms.

[0054] The top slot pattern in Figure 6 is the assignment pattern (hereinafter also referred to as the reference pattern) for each slot (up slot U, down slot D, special slot S) applied to the TDD of aerial node 1. The remaining two slot patterns in Figure 6 are examples of inverted synchronization patterns 1 and 2 that can be applied to the TDD of aerial node 2.

[0055] a) Reverse Synchronization Pattern 1 Reverse Synchronization Pattern 1 is obtained by reversing each slot according to the following rules. Reverse Synchronization Pattern 1 may also be called the first assignment pattern. - In the standard pattern, the first down slot D that switches from up slot U to down slot D is reversed to special slot S, and the other down slots D are reversed to up slot U. - The reverse of special slot S in the standard pattern is up slot U. - The reverse of up slot U in the standard pattern is down slot D.

[0056] b) Reverse Synchronization Pattern 2 Reverse synchronization pattern 2 is obtained by reversing each slot according to the following rules. Reverse synchronization pattern 2 may also be called the second assignment pattern. - In the standard pattern, the reversal of the rising slot U immediately before switching from rising slot U to falling slot D is set to special slot S, and the reversal of any other rising slot U is set to falling slot D. - The reversal of special slot S in the standard pattern is set to falling slot D. - The reversal of falling slot D in the standard pattern is set to rising slot U.

[0057] Thus, for example, if aerial node 1 applies the reference pattern, aerial node 2 applies either inverted synchronization pattern 1 or 2.

[0058] In the inverted synchronization pattern, the slots are inverted relative to the reference pattern as described above, so the timing of the down slot D of aerial node 1 and the timing of the down slot D of aerial node 2 do not coincide. Similarly, the timing of the up slot U of aerial node 1 and the timing of the up slot U of aerial node 2 do not coincide. Therefore, inter-beam interference caused by the overlapping timing of down slots D can be suppressed, and inter-beam interference caused by the overlapping timing of up slots U can also be suppressed.

[0059] (3.3) Timing shift of inverted synchronization In the above-mentioned reference pattern and inverted synchronization pattern, a special slot S is inserted between the up slot U and the down slot D, but there is a possibility that a propagation delay difference may occur that cannot be absorbed by the guard period within one special slot S.

[0060] To absorb propagation delay differences that cannot be fully absorbed within a single guard period (also called a guard slot) in such a special slot, inter-beam interference is suppressed by shifting the timing of one of the frames forward or backward by Tx.

[0061] Figure 7 shows the propagation delay. In Figure 7, the propagation delay between airborne node 1 and terminal A is defined as T1a, the propagation delay between airborne node 2 and terminal A is defined as T2a, the propagation delay between airborne node 2 and terminal B is defined as T2b, and the propagation delay between airborne node 1 and terminal B is defined as T1b.

[0062] I) In the case of inverted synchronization pattern 1, the frame timing of the side to which inverted synchronization is applied is shifted forward (advanced) by Tx.

[0063] In this case, the conditions for Tx that allow interference to be suppressed are as follows. Note that Tsp represents the length of the special slot S. (I-a) Interference suppression condition from aerial node 1 to terminal B: Tx ≤ Tsp + T2b - T1b (I-b) Interference suppression condition from aerial node 2 to terminal A: Tx ≥ T2a - T1a (I-c) Interference suppression condition from terminal A to aerial node 2: Tx ≤ Tsp + T1a - T2a (I-d) Interference suppression condition from terminal B to aerial node 1: Tx ≥ T1b - T2b

[0064] Figures 8 to 11 illustrate the conditions for Tx described above when applying the inverted synchronization pattern 1.

[0065] (I-a) Interference suppression conditions from aerial node 1 to terminal B Figure 8 shows the explanation of the interference suppression conditions from aerial node 1 to terminal B. As shown in Figure 8, the frame timing of aerial node 2 is advanced by Tx to suppress interference from aerial node 1 to terminal B.

[0066] Assuming that the DL end time of aerial node 1 is set to 0, the DL start time of terminal B is Tsp - Tx + T2b. On the other hand, the time when the interfering wave (end of DL of aerial node 1) last reaches terminal B is T1b. Therefore, in order to suppress interference, the following condition must be satisfied: T1b ≤ Tsp - Tx + T2b. Thus, the timing shift Tx that enables interference suppression is Tx ≤ Tsp + T2b - T1b.

[0067] (I-b) Interference suppression conditions from aerial node 2 to terminal A Figure 9 shows the explanation of the interference suppression conditions from aerial node 2 to terminal A. As shown in Figure 9, interference suppression from aerial node 2 to terminal A is performed by advancing the frame timing of aerial node 2 by Tx.

[0068] Assume that the DL completion time of aerial node 2 is base 0. The DL start time of terminal A is Tx + T1a. On the other hand, the time when the interfering wave (end of DL of aerial node 2) last reaches terminal A is T2a.

[0069] Therefore, in order to suppress interference, the following condition must be satisfied: T2a ≤ Tx + T1a. Thus, the timing shift Tx that enables interference suppression is Tx ≥ T2a - T1a.

[0070] (I-c) Interference suppression conditions from terminal A to aerial node 2 Figure 10 shows the explanation of the interference suppression conditions from terminal A to aerial node 2. As shown in Figure 10, interference suppression from terminal A to aerial node 2 is performed by advancing the frame timing of aerial node 2 by Tx.

[0071] Assuming that the UL end time of terminal A is set to 0, the UL start time of aerial node 2 is T1a + Tsp - Tx. On the other hand, the time when the interfering wave (end of terminal A's UL) last reaches aerial node 2 is T2a.

[0072] Therefore, in order to suppress interference, the following condition must be satisfied: T2a ≤ T1a + Tsp - Tx. Thus, the timing shift Tx that enables interference suppression is Tx ≤ Tsp + T1a - T2a.

[0073] (I-d) Interference suppression conditions from terminal B to aerial node 1 Figure 11 shows the explanation of the interference suppression conditions from terminal B to aerial node 1. As shown in Figure 11, the frame timing of aerial node 2 is advanced by Tx to suppress interference from terminal B to aerial node 1.

[0074] Assuming that the UL end time of terminal B is set to 0, the UL start time of aerial node 1 is T2b + Tx. On the other hand, the time when the interfering wave (end of terminal B's UL) last reaches aerial node 1 is T1b. Therefore, in order to suppress interference, the following condition must be satisfied: T1b ≤ T2b + Tx. Thus, the timing shift Tx that enables interference suppression is Tx ≥ T1b - T2b.

[0075] II) In the case of inverted synchronization pattern 2, the frame timing of the side to which inverted synchronization is applied is shifted backward by Tx (delayed).

[0076] In this case, the conditions for Tx that allow interference to be suppressed are as follows. Note that Tsp represents the length of the special slot S. (II-a) Interference suppression condition from aerial node 1 to terminal B: Tx≧T1b-T2b (II-b) Interference suppression condition from aerial node 2 to terminal A: Tx≦Tsp+T1a-T2a (II-c) Interference suppression condition from terminal A to aerial node 2: Tx≧T2a-T1a (II-d) Interference suppression condition from terminal B to aerial node 1: Tx≦Tsp+T2b-T1b

[0077] Figures 12 to 15 illustrate the conditions for Tx described above when applying the inverted synchronization pattern 2.

[0078] (II-a) Interference suppression conditions from aerial node 1 to terminal B Figure 12 shows the explanation of the interference suppression conditions from aerial node 1 to terminal B. As shown in Figure 12, interference suppression from aerial node 1 to terminal B is performed by delaying the frame timing of aerial node 2 by Tx.

[0079] Assuming that the DL end time of aerial node 1 is set to 0, the DL start time of terminal B is Tx + T2b. On the other hand, the time when the interfering wave (end of DL of aerial node 1) last reaches terminal B is T1b.

[0080] Therefore, in order to suppress interference, the following condition must be satisfied: T1b ≤ Tx + T2b. Thus, the timing shift Tx that enables interference suppression is Tx ≥ T1b - T2b.

[0081] (II-b) Interference suppression conditions from aerial node 2 to terminal A Figure 13 shows the explanation of the interference suppression conditions from aerial node 2 to terminal A. As shown in Figure 13, interference suppression from aerial node 2 to terminal A is performed by delaying the frame timing of aerial node 2 by Tx.

[0082] Assuming that the DL end time of aerial node 2 is set to 0, the DL start time of terminal A is Tsp - Tx + T1a. On the other hand, the time when the interfering wave (end of DL of aerial node 2) last reaches terminal A is T2a.

[0083] Therefore, in order to suppress interference, the following condition must be satisfied: T2a ≤ Tsp - Tx + T1a. Thus, the timing shift Tx that enables interference suppression is Tx ≤ Tsp + T1a - T2a.

[0084] (II-c) Interference suppression conditions from terminal A to airborne node 2 Figure 14 shows the explanation of the interference suppression conditions from terminal A to airborne node 2. As shown in Figure 14, interference suppression from terminal A to airborne node 2 is performed by delaying the frame timing of airborne node 2 by Tx.

[0085] Assuming that the UL end time of terminal A is set to 0, the UL start time of aerial node 2 is T1a + Tx. On the other hand, the time when the interfering wave (end of terminal A's UL) last reaches aerial node 2 is T2a.

[0086] Therefore, in order to suppress interference, the following condition must be satisfied: T2a ≤ T1a + Tx. Thus, the timing shift Tx that enables interference suppression is Tx ≥ T2a - T1a.

[0087] (II-d) Interference suppression conditions from terminal B to aerial node 1 Figure 15 shows the explanation of the interference suppression conditions from terminal B to aerial node 1. As shown in Figure 15, interference suppression from terminal B to aerial node 1 is performed by delaying the frame timing of aerial node 2 by Tx.

[0088] Assuming that the UL end time of terminal B is set to 0, the UL start time of aerial node 1 is T2b - Tx + Tsp. On the other hand, the time when the interfering wave (end of terminal B's UL) last reaches aerial node 1 is T1b.

[0089] Therefore, in order to suppress interference, the following condition must be satisfied: T1b ≤ T2b - Tx + Tsp. Thus, the timing shift Tx that enables interference suppression is Tx ≤ Tsp + T2b - T1b.

[0090] In this embodiment, for example, by setting Tx = 0.5ms, it is possible to completely suppress interference between downlink slots D and between uplink slots U when the following conditions are satisfied: • Tsp = 1ms (i.e., equivalent to the length of one slot when the subcarrier spacing is 15kHz) • T2a–T1a and T1b–T2b are both 0.5ms or less (i.e., propagation distance of 150km or less)

[0091] Furthermore, if either T2a–T1a or T1b–T2b is more than 0.5 ms apart, a horizontal separation distance of 91 km or more is maintained, so inter-beam interference (downstream) is not a problem.

[0092] In this embodiment, the timing shift Tx may be set to the fixed value described above (Tx = 0.5 ms). Alternatively, instead of necessarily using the fixed value described above, Tx may be determined by measuring the distance between aerial nodes and then set accordingly.

[0093] (3.4) Modifications (3.4.1) Method for resolving the bias in ascending and descending When applying an inverted synchronization pattern, the ratio of ascending slots to descending slots is the inverse of the ratio of ascending slots to descending slots in the reference pattern. For example, if aerial node 1 has an allocation pattern with many descending slots, aerial node 2 will have a large proportion of ascending slots. Therefore, when applying the inverted synchronization method, a bias in ascending and descending occurs.

[0094] Figure 16 illustrates the swapping of the ratio of downlink and uplink slots (DU pattern) between adjacent aerial nodes.

[0095] The left diagram in Figure 16 shows that aerial node 1 has a downlink-oriented DU pattern, with more downlink slots allocated compared to uplink slots. Therefore, aerial node 2, to which the inverted sync pattern is applied, will have an uplink-oriented DU pattern. In contrast, as shown in the right diagram of Figure 16, by changing aerial node 1 to an uplink-oriented DU pattern, aerial node 2, to which the inverted sync pattern is applied, can be changed to a downlink-oriented DU pattern.

[0096] In this way, by swapping DU patterns between airborne nodes, imbalances in the up and down links can be mitigated or eliminated. The trigger for this swapping of DU patterns may be periodic or dynamic. Specifically, the swapping can be performed at regular intervals, based on a control signal instructing the swap, or according to control from the network.

[0097] (3.4.2) When there are three or more aerial nodes Figure 17 shows an example of TDD application with three or more aerial nodes. In Figure 17, frequency division is applied to aerial nodes 1 and 2, whose ground coverage areas overlap. In contrast, since aerial node 3's ground coverage area does not overlap with that of aerial nodes 1 and 2, an inverted synchronization pattern is applied to the reference pattern of the adjacent aerial node 2.

[0098] According to this, by applying a combination of frequency division and inverted synchronization to frequency sharing between aerial nodes, it is possible to improve frequency utilization efficiency while suppressing inter-beam interference.

[0099] Each airborne node may control matters such as whether or not to perform frequency division, the frequency band to be used, and the control of inverted synchronization when using the same frequency, by receiving control signals instructed by the base station 300 or the ground GW station 400.

[0100] (3.4.3) Case of sharing an airborne node by multiple operators Figure 18 shows an example in which multiple telecommunications service providers (Company A, Company B, Company C) share the same airborne node (HAPS).

[0101] Figure 18 shows an example configuration combining fronthaul (O-RAN) and backhaul partitioning. Fronthaul partitioning refers to a configuration in which the core network and base station signal processing units (CU / DU) of the telecommunications service provider's network equipment are utilized, and an interface using fronthaul optical fiber transmission lines is used for input and output with the ground gateway station. Backhaul partitioning, on the other hand, refers to a configuration in which the telecommunications service provider's network equipment utilizes only the core network, and the base station, RU, and ground gateway station are all integrated into a single ground station facility.

[0102] In Figure 18, Company A connects its base stations (CU / DU) and ground gateway stations using fronthaul (O-RAN) splitting. In contrast, Companies B and C connect their core networks to Company A's base stations (CU / DU) using backhaul splitting.

[0103] In the feeder link FL, signals from companies A, B, and C are transmitted and received via frequency multiplexing. The airborne node (HAPS) forms cells on the ground using multiple beams. In the service link SL, TDD is applied with a common frequency and / or common beam. In Figure 18, company B is given an inverted synchronization pattern that is the inverted version of company A's reference pattern. company C is given a synchronization pattern that is the inverted version of company B's inverted synchronization pattern (the same as company A's reference pattern). Alternatively, cells that apply the same synchronization pattern, such as those of companies A and C, may be arranged so that they are not adjacent to each other.

[0104] Furthermore, inversion synchronization control for airborne nodes may be instructed from a ground GW station or from Company A's base station.

[0105] (3.4.4) Applying Inversion Synchronization to Different Beams Figure 19 shows an example of applying the inversion synchronization method to different beams 1 to 4 formed by an aerial node. The aerial node forms a coverage area on the ground with four different beams. In this case, the same reference pattern is applied to beams 1 and 3, and the inversion synchronization pattern of the reference pattern is applied to beams 2 and 4. By doing so, interference between different beams within the same aerial node can be suppressed.

[0106] (4) Effects and Benefits As shown in the operation examples above, when TDD is applied to a service link in a non-terrestrial network, even if it is difficult to install advanced interference control technologies such as null forming on the airborne node, it is possible to suppress inter-beam interference by applying the inverting synchronous method. As a result, adjacent airborne nodes can both effectively utilize the 15 MHz frequency band.

[0107] Furthermore, timing shifts make it possible to geographically bring aerial nodes closer together to a distance where inter-beam interference can be effectively suppressed.

[0108] Furthermore, by applying DU pattern swapping control, the upward and downward bias that occurs in the inverted synchronization method can be mitigated or eliminated.

[0109] Furthermore, even when multiple telecommunications service providers share the same aerial node, inter-beam interference can be suppressed.

[0110] (5) Other Embodiments The contents of the present invention have been described above in accordance with the embodiments, but it will be obvious to those skilled in the art that the present invention is not limited to these descriptions and that various modifications and improvements are possible.

[0111] For example, in the embodiment described above, the allocation pattern of downlink slots D and uplink slots U in the reference pattern applied to the airborne node 1 shown in Figure 6 is not limited to this. For example, there may be another pattern in which more uplink slots U are allocated than downlink slots D, or vice versa. For example, there may be slot allocation patterns such as those shown in 3GPP TS 36.211 for 4G and 3GPP TS 38.231 for NR.

[0112] In the embodiment described above, the subcarrier spacing SCS shown in Figure 6 is an example of 15 kHz, but this does not preclude the application of a different subcarrier spacing SCS. Also, one frame does not necessarily have to consist of 10 subframes.

[0113] Furthermore, in the embodiments described above, the aerial node 100 was explained using examples such as HAPS, but is not limited to these. For example, the aerial node 100 may be a ground node, such as a ground-based mobile phone base station. Also, in Figure 5, one or both of the aerial node 1 and aerial node 2 may be replaced with ground nodes. Furthermore, the satellite 500 was explained using examples such as a geostationary satellite (GEO) and a low-Earth orbit satellite (LEO), but is not limited to these. For example, the satellite 500 may be a relay path satellite (MEO) in orbit at an altitude of approximately 20,000 km.

[0114] Furthermore, in the above description, configure, activate, update, indicate, enable, specify, and select may be interpreted interchangeably. Similarly, link, associate, correspond, and map may be interpreted interchangeably, as may allocate, assign, monitor, and map.

[0115] Furthermore, "specific," "dedicated," "UE specific," and "UE individual" may be interpreted interchangeably. Similarly, "common," "shared," "group-common," "UE common," and "UE shared" may be interpreted interchangeably.

[0116] The block diagrams (Figures 2, 3, and 4) used in the description of the embodiments above show functional units. These functional blocks (components) are realized by any combination of at least one of hardware and software. Furthermore, the method of realizing each functional block is not particularly limited. That is, each functional block may be realized using one device that is physically or logically coupled, or it may be realized using two or more physically or logically separated devices that are directly or indirectly connected (for example, using wired or wireless connections). A functional block may also be realized by combining software with the one or more devices described above.

[0117] Functions include, but are not limited to, judgment, decision, judgment, calculation, calculation, processing, derivation, investigation, exploration, confirmation, reception, transmission, output, access, resolution, selection, selection, establishment, comparison, assumption, expectation, assumption, broadcasting, notifying, communicating, forwarding, configuring, reconfiguring, allocating (mapping), and assigning. For example, a functional block (configuration part) that enables transmission is called a transmitting unit or transmitter. In any case, as mentioned above, the method of implementation is not particularly limited.

[0118] Furthermore, the aerial node 100, base station 300, and ground GW station 400 (the device) described above may function as a computer that processes the wireless communication method of this disclosure. Figure 20 shows an example of the hardware configuration of the device. As shown in Figure 20, the device may be configured as a computer device including a processor 1001, memory 1002, storage 1003, communication device 1004, input device 1005, output device 1006, and bus 1007.

[0119] In the following explanation, the term "device" can be replaced with "circuit," "device," "unit," etc. The hardware configuration of the device may include one or more of the devices shown in the diagram, or it may be configured to omit some of the devices.

[0120] Each functional block of the device (Figures 2, 3, 4, etc.) is implemented by any hardware element of the computer device, or a combination of such hardware elements.

[0121] Furthermore, each function in the device is realized by loading predetermined software (programs) onto hardware such as the processor 1001 and memory 1002, which allows the processor 1001 to perform calculations, control communication by the communication device 1004, and control at least one of the reading and writing of data in the memory 1002 and storage 1003.

[0122] The processor 1001 controls the entire computer, for example, by running an operating system. The processor 1001 may consist of a central processing unit (CPU) that includes interfaces with peripheral devices, control units, arithmetic units, registers, and so on.

[0123] Furthermore, the processor 1001 reads programs (program code), 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 accordingly. The program used is one that causes the computer to execute at least a part of the operations described in the above embodiment. Moreover, the above-mentioned various processes may be executed by one processor 1001, or by two or more processors 1001 simultaneously or sequentially. The processor 1001 may be implemented by one or more chips. The program may also be transmitted from a network via a telecommunications line.

[0124] Memory 1002 is a computer-readable recording medium and may consist of at least one of the following: Read Only Memory (ROM), Erasable Programmable ROM (EPROM), Electrically Erasable Programmable ROM (EEPROM), Random Access Memory (RAM), etc. Memory 1002 may also be called a register, cache, main memory, etc. Memory 1002 can store a program (program code), software module, etc., that can execute a method according to one embodiment of this disclosure.

[0125] Storage 1003 is a computer-readable recording medium and may consist of at least one of the following: an optical disc such as a Compact Disc ROM (CD-ROM), a hard disk drive, a flexible disk, a magneto-optical disk (e.g., Compact Disc, Digital Multipurpose Disc, Blu-ray® Disc), a smart card, flash memory (e.g., a card, stick, key drive), a floppy® disk, a magnetic strip, etc. Storage 1003 may also be called an auxiliary storage device. The recording medium described above may also be, for example, a database, server, or other suitable medium including at least one of memory 1002 and storage 1003.

[0126] The communication device 1004 is hardware (transceiver / receiver device) for communicating between computers via at least one of a wired network and a wireless network, and is also referred to as a network device, network controller, network card, communication module, etc.

[0127] The communication device 1004 may be configured to include, for example, a high-frequency switch, a duplexer, a filter, a frequency synthesizer, etc., in order to implement at least one of frequency division duplex (FDD) and time division duplex (TDD).

[0128] The input device 1005 is an input device that accepts input from an external source (e.g., a keyboard, mouse, microphone, switch, button, sensor, etc.). The output device 1006 is an output device that outputs to an external source (e.g., a display, speaker, LED lamp, etc.). The input device 1005 and the output device 1006 may be configured as an integrated unit (e.g., a touch panel).

[0129] Furthermore, each device, such as the processor 1001 and the memory 1002, is connected by a bus 1007 for communicating information. The bus 1007 may be configured using a single bus, or different buses may be configured for each device.

[0130] Furthermore, the device may include hardware such as a microprocessor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a programmable logic device (PLD), and a field-programmable gate array (FPGA), and some or all of each functional block may be implemented by such hardware. For example, processor 1001 may be implemented using at least one of these hardware components.

[0131] Furthermore, notification of information is not limited to the embodiments described herein and may be carried out by other means. For example, notification of information may be carried out by physical layer signaling (e.g., Downlink Control Information (DCI), Uplink Control Information (UCI)), upper layer signaling (e.g., RRC signaling, Medium Access Control (MAC) signaling, broadcast information (Master Information Block (MIB), System Information Block (SIB))), other signals, or combinations thereof. RRC signaling may also be called RRC messages, and may be, for example, RRC Connection Setup messages, RRC Connection Reconfiguration messages, etc.

[0132] Each aspect / embodiment described herein may be applied to at least one of the following: Long Term Evolution (LTE), LTE-Advanced (LTE-A), SUPER 3G, IMT-Advanced, 4th generation mobile communication system (4G), 5th generation mobile communication system (5G), 6th generation mobile communication system (6G), xth generation mobile communication system (xG) (where x is, for example, an integer or decimal), Future Radio Access (FRA), New Radio (NR), W-CDMA®, GSM®, CDMA2000, Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi®), IEEE 802.16 (WiMAX®), IEEE 802.20, Ultra-WideBand (UWB), Bluetooth®, and other appropriate systems, as well as next-generation systems extended based thereon. Furthermore, multiple systems may be applied in combination (for example, a combination of at least one of LTE and LTE-A with 5G).

[0133] The processing procedures, sequences, flowcharts, etc., of each aspect / embodiment described in this disclosure may be reordered, provided they do not contradict each other. For example, the methods described in this disclosure present various step elements using exemplary order and are not limited to the specific order presented.

[0134] The specific operations described in this disclosure as being performed by a base station may, in some cases, be performed by its upper node. 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 can be performed by the base station and at least one other network node (for example, an MME or S-GW, but not limited to these). Although the above example illustrates the case where there is one other network node besides the base station, it may also be a combination of multiple other network nodes (for example, an MME and an S-GW).

[0135] Information and signals (such as data) can be output from a higher layer (or lower layer) to a lower layer (or higher layer). Input and output may occur via multiple network nodes.

[0136] Input and output information may be stored in a specific location (e.g., memory) or managed using a management table. Input and output information may be overwritten, updated, or appended to. Output information may be deleted. Input information may be sent to other devices.

[0137] The determination may be made by a value represented by one bit (0 or 1), by a boolean value (true or false), or by a numerical comparison (for example, a comparison with a predetermined value).

[0138] Each aspect / embodiment described in this disclosure may be used individually, in combination, or switched between as needed during implementation. Furthermore, notification of specific information (e.g., notification that "X is") is not limited to explicit notification, but may also be implicit (e.g., by not providing such notification).

[0139] Software should be broadly interpreted to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executable files, execution threads, procedures, functions, and so on, whether they are called software, firmware, middleware, microcode, hardware description languages, or by any other name.

[0140] Furthermore, software, instructions, information, etc., may be transmitted and received via a transmission medium. For example, if software is transmitted from a website, server, or other remote source using at least one of wired technologies (such as coaxial cable, fiber optic cable, twisted pair, or Digital Subscriber Line (DSL)) and wireless technologies (such as infrared or microwave), then at least one of these wired and wireless technologies is included in the definition of a transmission medium.

[0141] The information, signals, etc. described in this disclosure may be represented using any of the various different technologies. For example, the data, instructions, commands, information, signals, bits, symbols, chips, etc. that may be referred to throughout the above description may be represented by voltage, current, electromagnetic waves, magnetic fields or magnetic particles, optical fields or photons, or any combination thereof.

[0142] In addition, terms used 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 the channel and symbol may be a signal (signaling). Also, a signal may be a message. Furthermore, a component carrier (CC) may be called a carrier frequency, cell, frequency carrier, etc.

[0143] The terms “system” and “network” as used in this disclosure are interchangeable.

[0144] Furthermore, the information, parameters, etc., described in this disclosure may be expressed using absolute values, relative values ​​from a given value, or other corresponding information. For example, wireless resources may be indicated by an index.

[0145] The names used for the parameters described above are not restrictive in any way. Furthermore, the formulas and other expressions using these parameters may differ from those expressly disclosed in this disclosure. Since various channels (e.g., PUCCH, PDCCH, etc.) and information elements can be identified by any suitable name, the various names assigned to these various channels and information elements are not restrictive in any way.

[0146] In this disclosure, terms such as "Base Station (BS)," "wireless 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.

[0147] A base station can house one or more (e.g., three) cells (also called sectors). If a base station houses multiple cells, the entire coverage area of ​​the base station can be divided into multiple smaller areas, each of which can also be provided with communication services by a base station subsystem (e.g., a small indoor base station (Remote Radio Head: RRH)).

[0148] The terms "cell" or "sector" refer to a portion or all of the coverage area of ​​at least one of the base stations and base station subsystems that provide communication services in this coverage.

[0149] In this disclosure, the transmission of information by a base station to a terminal may be interpreted as the base station instructing the terminal to perform control or operation based on the information.

[0150] In this disclosure, terms such as "Mobile Station (MS)," "user terminal," "User Equipment (UE)," and "terminal" may be used interchangeably.

[0151] 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 appropriate term.

[0152] At least one of the base station and the mobile station may be called a transmitting device, a receiving device, a communication device, etc. At least one of the base station and the mobile station may also be a device mounted on a mobile body, the mobile body itself, etc. The mobile body may be a vehicle (e.g., a car, an airplane, etc.), an unmanned mobile body (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 be a device that does not necessarily move during communication operation. 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.

[0153] Furthermore, the term "base station" in this disclosure may be interpreted as "mobile station" (user terminal, hereinafter the same). For example, the various aspects / embodiments of this 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), Vehicle-to-Everything (V2X), etc.). In this case, the mobile station may have the functions that a base station has. Also, terms such as "uplink" and "downlink" may be interpreted as terms corresponding to terminal-to-terminal communication (for example, "side"). For example, uplink channel, downlink channel, etc. may be interpreted as side channel (or side link).

[0154] Similarly, the term "mobile station" in this disclosure may be interpreted as "base station." In this case, the base station may be configured to have the functions that a mobile station has.

[0155] A wireless frame may consist of one or more frames in the time domain. Each of these one or more frames in the time domain may be called a subframe. A subframe may further consist 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.

[0156] Numerology may be communication parameters applied to at least one of the transmission and reception of a signal or channel. Numerology may include, for example, at least one of the following: subcarrier spacing (SCS), bandwidth, symbol length, cyclic prefix length, transmission time interval (TTI), number of symbols per TTI, radio frame configuration, specific filtering processes performed by the transceiver in the frequency domain, and specific windowing processes performed by the transceiver in the time domain.

[0157] A slot may consist of one or more symbols in the time domain (such as Orthogonal Frequency Division Multiplexing (OFDM) symbols or Single Carrier Frequency Division Multiple Access (SC-FDMA) symbols). A slot may also be a time unit based on neurology.

[0158] A slot may include multiple mini-slots. Each mini-slot may consist of one or more symbols in the time domain. Mini-slots may also be called sub-slots. Mini-slots may consist of fewer symbols than a slot. A PDSCH (or PUSCH) transmitted in a time unit larger than a mini-slot may be called PDSCH (or PUSCH) mapping type A. A PDSCH (or PUSCH) transmitted using a mini-slot may be called PDSCH (or PUSCH) mapping type B.

[0159] Wireless frames, subframes, slots, minislots, and symbols all represent units of time when transmitting a signal. Different names may be used for each of these terms.

[0160] For example, one subframe may be called a transmission time interval (TTI), multiple consecutive subframes may be called a TTI, or one slot or one minislot may be called a TTI. In other words, at least one of a subframe and a TTI may be a subframe in existing LTE (1ms), a period shorter than 1ms (e.g., 1-13 symbols), or a period longer than 1ms. Note that the unit representing the TTI may be called a slot, minislot, etc., instead of a subframe.

[0161] Here, TTI refers to, for example, the smallest unit of time for scheduling in wireless communication. For example, in an LTE system, the base station schedules each user terminal to allocate wireless resources (such as the frequency bandwidth and transmission power available to each user terminal) in TTI units. However, the definition of TTI is not limited to this.

[0162] TTI may be a transmission time unit for channel-encoded data packets (transport blocks), code blocks, code words, etc., or it may be a processing unit for scheduling, link adaptation, etc. Note that when a TTI is given, the actual time interval (e.g., number of symbols) in which the transport block, code block, code word, etc. are mapped may be shorter than the given TTI.

[0163] Furthermore, if one slot or one mini-slot is referred to as TTI, then one or more TTIs (i.e., one or more slots or one or more mini-slots) may constitute the minimum time unit of scheduling. In addition, the number of slots (number of mini-slots) that constitute the minimum time unit of scheduling may be controlled.

[0164] A TTI with a time length of 1ms may also be called a normal TTI, long TTI, normal subframe, long subframe, slot, etc. A TTI shorter than a normal TTI may also be called a shortened TTI, short TTI, partial or fractional TTI, shortened subframe, short subframe, mini slot, sub slot, slot, etc.

[0165] Furthermore, long TTIs (e.g., normal TTIs, subframes, etc.) may be interpreted as TTIs with a time length exceeding 1 ms, and short TTIs (e.g., shortened TTIs, etc.) may be interpreted as TTIs with a TTI length less than that of a long TTI but 1 ms or more.

[0166] A resource block (RB) is a resource allocation unit in the time domain and frequency domain, and in the frequency domain, it may contain one or more consecutive subcarriers. The number of subcarriers in an RB may be the same regardless of the neurology, for example, 12. The number of subcarriers in an RB may be determined based on the neurology.

[0167] Furthermore, the time domain of RB may contain one or more symbols and may be the length of one slot, one minislot, one subframe, or one TTI. One TTI, one subframe, etc., may each consist of one or more resource blocks.

[0168] One or more RBs may also be called a Physical RB (PRB), Sub-Carrier Group (SCG), Resource Element Group (REG), PRB pair, RB pair, etc.

[0169] Furthermore, a resource block may consist of one or more resource elements (REs). For example, one RE may be a radio resource area comprising one subcarrier and one symbol.

[0170] A Bandwidth Part (BWP), also known as a partial bandwidth, may represent a subset of consecutive common resource blocks (RBs) for a given neurology in a given carrier. Here, the common RBs may be identified by an index of the RBs relative to the carrier's common reference point. PRBs may be defined and numbered within a given BWP.

[0171] A BWP may include BWPs for UL (UL BWP) and BWPs for DL ​​(DL BWP). One or more BWPs may be set within a single carrier for a UE.

[0172] At least one of the configured BWPs may be active, and the UE does not need to assume that it will send or receive a given signal / channel outside of the active BWP. In this disclosure, terms such as "cell" and "carrier" may be read as "BWP".

[0173] The structures described above, such as wireless frames, subframes, slots, minislots, and symbols, are merely illustrative. For example, the number of subframes included in a wireless frame, the number of slots per subframe or wireless 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, and the number of symbols, symbol length, and cyclic prefix (CP) length within a TTI can be varied in various ways.

[0174] The terms “connected,” “coupled,” and any variations thereof mean 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” with each other. The coupling or connection between elements may be physical, logical, or a combination thereof. For example, “connection” may be reinterpreted as “access.” As used in this disclosure, two elements may be considered to be “connected” or “coupled” with each other using at least one of one or more wires, cables, and printed electrical connections, and, in some non-limiting and non-exclusive examples, electromagnetic energy having wavelengths in the radio frequency domain, microwave domain, and optical (both visible and invisible) domain.

[0175] The reference signal can also be abbreviated as Reference Signal (RS), and may be called a pilot depending on the applicable standard.

[0176] In this disclosure, the phrase "based on" does not mean "based solely on" unless otherwise specified. In other words, the phrase "based on" means both "based solely on" and "based at least on."

[0177] In the configuration of each of the above devices, "means" may be replaced with "part," "circuit," "device," etc.

[0178] Any reference to elements using designations such as “First,” “Second,” etc., as used in this disclosure does not generally limit the quantity or order of those elements. These designations may be used in this disclosure as a convenient way to distinguish between two or more elements. Accordingly, references to the First and Second elements do not imply that only two elements may be employed therein, or that the First element must precede the Second element in any way.

[0179] Where the terms “include,” “including,” and variations thereof are used in this disclosure, these terms are intended to be inclusive, as is the term “comprising.” Furthermore, the term “or” as used in this disclosure is not intended to be exclusive OR.

[0180] In this disclosure, if articles are added through translation, such as a, an, and the in English, this disclosure may include the fact that the noun following these articles is plural.

[0181] The terms “determining” and “determining” as used in this disclosure may encompass a wide variety of actions. “Determining” and “determining” may include, for example, judging, calculating, computing, processing, deriving, investigating, looking up, searching, or inquiring (e.g., searching in a table, database, or other data structure), or ascertaining. “Determining” and “determining” may also include receiving (e.g., receiving information), transmitting (e.g., sending information), inputting, outputting, or accessing (e.g., accessing data in memory). Furthermore, "judgment" and "decision" can include considering something as having "judgmented" or "decided" after resolving, selecting, choosing, establishing, comparing, etc. In other words, "judgment" and "decision" can include considering something as having "judgmented" or "decided" about some action. Also, "judgment (decision)" can be reinterpreted as "assuming," "expecting," or "considering."

[0182] In this 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 "combine" may be interpreted similarly to "different."

[0183] Although the present disclosure has been described in detail above, it will be clear to those skilled in the art that the present disclosure is not limited to the embodiments described herein. The present disclosure may be implemented in modified and altered forms without departing from the intent and scope of the present disclosure as defined by the claims. Accordingly, the descriptions in the present disclosure are for illustrative purposes only and are not intended to be restrictive in any way.

[0184] 10 Wireless communication system 100 Airborne node 110 Aircraft systems section 120 Payload 130 FL communication section 140 SL communication section 150 Inverted synchronous control section 160 Control section 200 UE 300 Base station 310 Ground station communication section 320 Core network communication section 330 Inverted synchronous control section 340 Control section 400 Satellite GW earth station 410 FL communication section 420 Base station communication section 430 Inverted synchronous control section 440 Control section 500 Satellite 1001 Processor 1002 Memory 1003 Storage 1004 Communication device 1005 Input device 1006 Output device 1007 Bus

Claims

1. An air node comprising a communication unit that communicates with a ground terminal using time-division duplexing, and a control unit that controls the timing of the uplink slot in the time-division duplexing so as not to match the timing of the uplink slot in the time-division duplexing of other air nodes, and the timing of the downlink slot in the time-division duplexing so as not to match the timing of the downlink slot in the time-division duplexing of other air nodes.

2. The aerial node according to claim 1, wherein the control unit applies either a first assignment pattern that associates a guard slot with the first down slot in which the other aerial node switches from the up slot to the down slot, or a second assignment pattern that associates a guard slot with the last up slot in which the other aerial node switches from the up slot to the down slot.

3. The aerial node according to claim 1, wherein the control unit provides a timing shift to absorb propagation delays exceeding the guard slot inserted between the up slot and the down slot.

4. The aerial node according to claim 3, wherein the timing shift is set to a fixed value or a value corresponding to the distance from the other aerial node.

5. The aerial node according to claim 1, wherein the control unit swaps the ratio of the up slots to the down slots with the ratio of the up slots to the down slots in the other aerial nodes.

6. An aerial node comprising: a communication unit that provides communications from different operators for each beam to a ground terminal using time-division duplexing; and a control unit that controls the timing of the uplink slots in the beam of the first operator so as not to match the timing of the uplink slots in the beam of the second operator, and the timing of the downlink slots in the beam of the first operator so as not to match the timing of the downlink slots in the beam of the second operator.

7. A ground station device comprising: a transmitting unit that transmits a control signal to a first airborne node that communicates with a ground terminal using time-division duplexing, instructing it on an allocation pattern for uplink and downlink slots; and a control unit that generates the allocation pattern such that the timing of the uplink slot of the first airborne node does not match the timing of the uplink slot in time-division duplexing of the second airborne node, and the timing of the downlink slot of the first airborne node does not match the timing of the downlink slot in time-division duplexing of the second airborne node.

8. A ground node comprising a communication unit that communicates with a ground terminal using time division duplexing, and a control unit that controls the timing of the uplink slot in the time division duplexing so as not to match the timing of the uplink slot in the time division duplexing of other ground nodes, and the timing of the downlink slot in the time division duplexing so as not to match the timing of the downlink slot in the time division duplexing of other ground nodes.

9. A ground node comprising a communication unit that provides communications from different operators for each beam to a ground terminal using time-division duplexing, and a control unit that controls the timing of the uplink slots in the beam of the first operator so as not to match the timing of the uplink slots in the beam of the second operator, and the timing of the downlink slots in the beam of the first operator so as not to match the timing of the downlink slots in the beam of the second operator.

10. A ground station device comprising: a transmitting unit that transmits a control signal to a first ground node that communicates with a ground terminal using time division duplexing, instructing it on an allocation pattern for uplink and downlink slots; and a control unit that generates the allocation pattern such that the timing of the uplink slot of the first ground node does not match the timing of the uplink slot in time division duplexing of the second ground node, and the timing of the downlink slot of the first ground node does not match the timing of the downlink slot in time division duplexing of the second ground node.

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