The present invention relates to technology according to which an airspace for the flight of a flight vehicle is assigned to the flight vehicle.
In order to achieve faster speeds than in Long Term Evolution (LTE), the 3rd Generation Partnership Project (3GPP) has created the LTE-Advanced (hereinafter, the term “LTE” includes LTE-Advanced) standard. The 3GPP is also reviewing specifications for a system called 5G (5th generation mobile communication system) or the like as a successor to LTE.
Under LTE, it is defined that the transmit power of a physical uplink channel is controlled based on the path loss between a radio base station (eNB) and a radio communication apparatus (UE). Specifically, it is defined that the transmit power of the physical uplink shared channel (specifically, PUSCH: Physical Uplink Shared Channel) is controlled based on the path loss of the physical downlink channel (e.g., see 1: 3GPP TS 36.213 V14.2.0 Subclause 5.1.1 Physical uplink shared channel, 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Evolved Universal Terrestrial Radio Access (E-UTRA); Physical layer procedures (Release 14).
There are also radio communication apparatuses (hereinafter called specified radio communication apparatuses) that carry out communication in the sky, where the line-of-sight is good in all directions, rather than on the ground, as with radio communication apparatuses provided in unmanned flight vehicles called drones.
With such a specified radio communication apparatus, the path loss of the physical downlink channel from the radio base station is small because the line-of-sight is good. In other words, the reception power of the physical downlink channel is high in the specified radio communication apparatus. Furthermore, one specified radio communication apparatus has a good line-of-sight to multiple radio base stations in the vicinity, and therefore the reception power of the physical downlink channel from each of the radio base stations is high, and a problem occurs in which the radio signals on the physical downlink channels from the radio base stations interfere with each other. As a result, there is a risk that communication between a radio base station and the radio communication apparatus of a flight vehicle that is connected to the radio base station will be negatively influenced.
The present invention is achieved in light of the foregoing circumstances, and an object of the present invention is to suppress the case where communication performed between a radio base station and a radio communication apparatus of a flight vehicle is negatively influenced in an airspace in which interference occurs due to radio signals from the radio base station.
In one aspect, the present invention provides a flight vehicle management apparatus including: a specification unit configured to specify, for each airspace, a parameter regarding a communication quality of a radio communication apparatus in a cell formed by a radio base station; and an assignment unit configured to, for each airspace, assign a flight vehicle having a radio communication apparatus that performs communication using at least a physical downlink channel as a flight vehicle that is to fly in the airspace, and to limit assignment of a flight vehicle to an interference airspace, the interference airspace being an airspace in which the number of radio base stations for which the parameter specified by the specification unit is in a first range is greater than or equal to a predetermined number.
An aspect is possible in which in a case of a radio cell that is formed by, from among a group of radio base stations for which the parameter specified by specification unit is in the predetermined range, a radio base station that is not a radio base station connected to a radio communication apparatus provided in a flight vehicle, the assignment unit relaxes the limiting of assignment of a flight vehicle if the number of, or a communication load of, other radio communication apparatuses located in the radio cell is less than or equal to a threshold value.
An aspect is possible in which in a case of relaxing the limiting, the assignment unit assigns a larger number of flight vehicles to the interference airspace than in a case of not relaxing the limiting.
An aspect is possible in which in a case of relaxing the limiting, the assignment unit sets a smaller size for the interference airspace than in a case of not relaxing the limiting.
An aspect is possible in which in a case where a radio communication apparatus of a flight vehicle has little need to perform communication using a physical downlink channel, the assignment unit assigns the flight vehicle to the interference airspace.
According to the present invention, it is possible to suppress the case where communication performed between a radio base station and a radio communication apparatus of a flight vehicle is negatively influenced in an airspace in which interference occurs due to radio signals from the radio base station.
Each flight vehicle 10 physically includes a computer, various sensors controlled by the computer, and a drive mechanism that includes motors, rotor blades, and the like, and the computer includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and an auxiliary storage apparatus, as well as a positioning unit for measuring the position of the flight vehicle, a communication IF (Interface) for connection to radio communication apparatuses 20, and the like. Flight vehicle 10 flies in the air by the computer controlling the drive mechanism in accordance with a flight plan or the like that has been assigned to flight vehicle 10 and includes airspace positions, passage times for such positions, and the like. Note that flight vehicle 10 need only being a flying apparatus, and is also called a UAS (Unmanned Aircraft System), for example.
A radio communication system is constructed by network 90 that includes radio communication apparatuses 20 and 30 and radio base stations 40. This radio communication system is a radio communication system that complies with LTE (Long Term Evolution) standards, for example. In LTE, radio communication apparatuses 20 and 30 are called UEs, and radio base stations 40 are called eNBs. The areas where radio communication can be performed with radio base stations 40 are called cells. Radio communication apparatuses 20 and 30 that are located in (in the zone of) a cell perform radio communication with radio base station 40 that forms that cell. For example, radio communication apparatus 30 used by a user located on the ground executes radio communication with radio base station 40 located on the ground. On the other hand, radio communication apparatus 20 provided in flight vehicle 10 executes radio communication with radio base station 40 both when on the ground and when in the air (e.g., an airspace with an altitude of 30 m or more).
Flight vehicle management apparatus 50 is an information processing apparatus that controls and manages the flight of flight vehicles 10. In the present embodiment, flight vehicle management apparatus 50 particularly has a feature in processing for assigning flight airspaces to flight vehicles 10. This assignment of airspaces to flight vehicles 10 refers to processing in which flight vehicle management apparatus 50 stores identification information of flight vehicles 10 in correspondence with identification information of airspaces for the flight thereof as flight plans for corresponding flight vehicles 10. Note that functions in flight vehicle operation control are generally distributed among multiple systems such as an FIMS (Flight Information Management System) and a UASSP (UAS Service Provider), and flight vehicle management apparatus 50 of present embodiment may be implemented using such systems, or may be implemented using any one of such systems. Also, some of the functions of flight vehicle management apparatus 50, such as the functions of later-described specification unit (airspace communication state detection function), may be implanted using an apparatus other than a general FIMS or UASSP.
The following describes communication interference that occurs in the radio communication system. As shown in
For this reason, in the case of radio communication apparatus 20a, the path loss of the physical downlink channel from radio base station 40a, the path loss of the physical downlink channel from radio base station 40b, and the path loss of the physical downlink channel from radio base station 40c are all small. As a result, signal waves on the physical downlink channels from radio base stations 40a, 40b, and 40c interfere with each other, and non-connection-partner radio base stations 40b and 40c become sources of interference in radio communication apparatus 20a that is connected to radio base station 40a. In other words, signal waves from non-connection-partner radio base stations 40b and 40c become interference waves with respect to signal waves that radio communication apparatus 20a receives from connection-partner radio base station 40a. Accordingly, there is a risk that communication between radio base station 40a and radio communication apparatus 20a will be negatively influenced. In the present embodiment, negative influence caused by such interference is suppressed.
In
For each airspace, specification unit 52 specifies a parameter regarding the communication quality of radio communication apparatuses 20 and 30 in the cell formed by the corresponding radio base station 40 (e.g., the path loss of the physical downlink channel from radio base station 40 to radio communication apparatuses 20 and 30). Each airspace is an airspace that has been defined in advance based on a predetermined reference, for example.
Assignment unit 53 determines flight airspaces that are to be assigned to flight vehicles 10. Specifically, assignment unit 53 performs processing for assigning flight vehicles 10 to airspaces. At this time, assignment unit 53 limits the assignment of flight vehicle 10 to a specified airspace in which the number of radio base stations 40 for which the parameter specified by specification unit 52 is in a predetermined range indicating good communication quality (e.g., the number of radio base stations 40 for which the path loss of the physical downlink channel to radio communication apparatus 20 is less than or equal to a threshold value), is greater than or equal to a predetermined number (e.g., 2). More specifically, if there are multiple radio base stations 40 that have a good line-of-sight to the sky, that is to say, the path loss of the physical downlink channel to radio communication apparatus 20 provided in a certain flight vehicle 10 is less than or equal to a threshold value, then interference such as that shown in
The following describes operations in the present embodiment. In
Assignment unit 53 specifies an airspace in which the number of radio base stations 40 for which the parameter specified by specification unit 52 is in a predetermined range is a predetermined number or more, as an airspace in which there is a possibility of the interference shown in
Then, in accordance with desired flight content that was requested in advance by the operators of flight vehicles 10, for each airspace, assignment unit 53 assigns flight vehicles 10 that are to fly in the airspace, and creates flight plans that include flight paths, flight periods, and the like (step S13). The flight plans are stored in tracking unit 51.
At this time, assignment unit 53 limits the assignment of flight vehicles 10 to the above-described interference airspace. Specifically, assignment unit 53 limits the number of flight vehicles 10 that are assigned to an interference airspace to a greater extent than the number of flight vehicles 10 that are assigned to an airspace other than the interference airspace. For example, assignment unit 53 sets U1 as the upper limit number of flight vehicles 10 that are assigned per unit volume of an interference airspace, and sets U2 as the upper limit number of flight vehicles 10 that are assigned per unit volume of an airspace other than the interference airspace (U1<U2). The minimum value of U1 is 0. Assignment unit 53 assigns flight vehicles 10 to airspaces by writing flight plans to tracking unit 51, in which the identification information of flight vehicles 10 are associated with the identification information of airspaces for flight of such flight vehicles 10 in accordance with the above-described upper limits. Accordingly, there are fewer opportunities for transmission from radio base stations 40b and 40c to radio communication apparatus 20 on the physical downlink channel as shown in
According to the embodiment described above, it is possible to suppress the case where communication performed between radio base station 40 and radio communication apparatus 20 of flight vehicle 10 is negatively influenced in an airspace in which interference occurs due to radio signals from radio base station 40.
Variations
The present invention is not limited to the embodiment described above. The above-described embodiment may be modified as described below. Also, two or more of the following variations may be implemented in combination with each other.
Variation 1
In the case of a radio cell that includes an interference airspace and is formed by, from among a group of radio base stations 40 for which the parameter specified by specification unit 52 is in the predetermined range (e.g., the path loss value of the physical downlink channel is less than or equal to a threshold value, and the predicted interference possibility is high), radio base station 40 that is not radio base station 40 connected to radio communication apparatus 20 provided in flight vehicle 10, assignment unit 53 may relax the limiting of assignment of flight vehicles 10 if the number of, or the communication load of, radio communication apparatuses located in the cell is less than or equal to a threshold value. If the condition that a cell that includes an interference airspace has few or no ground-based radio communication apparatuses 30 located therein, or that the communication load of thereof is low or zero, is satisfied, radio communication apparatus 20 may be assigned to the interference airspace regardless of whether or not it has an interference avoidance function. Such processing corresponds to relaxing the limiting of assignment of flight vehicles 10. Note that a configuration is possible in which consideration is not given to the number of, or the communication load of, radio communication apparatuses 30 that are located in the cell formed by radio base station 40 to which radio communication apparatus 20 provided in flight vehicle 10 is connected.
Also, a configuration is possible in which assignment unit 53 sets a higher number of radio communication apparatuses 20 that are assigned to an interference airspace when the above-described condition is satisfied than when the condition is not satisfied. Also, a configuration is possible in which in the case where the number of, or the communication load of, radio communication apparatuses 30 that are located in a cell that includes an interference airspace is less than or equal to a threshold value, assignment unit 53 eliminates the interference airspace or reduces the size thereof, or raises the threshold value for the path loss in that airspace. Accordingly, the interference airspace will be reduced in size.
Note that assignment unit 53 may detect the situation where the number of, or the communication load of, radio communication apparatuses 30 that are located in a cell that includes an interference airspace is less than or equal to a threshold value, by, similarly to the parameter specification performed by specification unit 52, causing radio communication apparatuses 20 of flight vehicles 10 to acquire the path loss of the physical downlink channel in the corresponding airspaces, and collecting such information, or may detect the aforementioned situation based on the positions and the sizes of the cells of radio base stations 40, as well as map information and a predetermined wave propagation model.
Variation 2
Assignment unit 53 may assign flight vehicle 10 to an interference airspace if radio communication apparatus 20 of flight vehicle 10 has little need to perform communication using the physical downlink channel. This is because if flight vehicle 10 is a flight vehicle that includes a function for autonomously avoiding collisions, or it can be determined based on a flight history or the like that flight vehicle 10 can fly stably for example, then even if radio communication apparatus 20 of flight vehicle 10 suffers interference, that is sometimes not a big problem for the flight of flight vehicle 10 because flight control based on communication performed by radio communication apparatus 20 is not essential. In this way, if radio communication apparatus 20 of flight vehicle 10 has little need to perform communication using the physical downlink channel, assignment unit 53 assigns flight vehicle 10 to an interference airspace. Regarding the determination of whether or not radio communication apparatus 20 has little need to perform communication using the physical downlink channel, it is sufficient that identification information of radio communication apparatus 20 or identification information of flight vehicle 10 that has radio communication apparatus 20 is stored in correspondence with information indicating the degree of need for communication, and that the aforementioned determination is made based on the identification information of radio communication apparatus 20 or the identification information of flight vehicle 10 that has radio communication apparatus 20.
Variation 3
In the present invention, it is sufficient that radio communication apparatus 20 provided in flight vehicle 10 is an apparatus that performs communication that is influenced by interference, that is to say, performs communication using at least a physical downlink channel.
The block diagrams used in the above description of the embodiments shows blocks in units of functions. These functional blocks (configuration units) are realized by any combination of hardware and/or software. Furthermore, there are no particular limitations on the means for realizing the functional blocks. In other words, the functional blocks may be realized by one physically and/or logically combined apparatus, or a plurality of physically and/or logically separated apparatuses that are connected directly and/or indirectly (for example, in a wired and/or wireless manner).
Although the LTE standard is described as an example in the above embodiment, the radio communication standard is not limited to this, and another standard such as 3G or 5G may be used. In other words, the aspects/embodiments described in the present description may be employed to a system that uses LTE(Long Term Evolution), LTE-A(LTE-Advanced), SUPER3G, IMT-Advanced, 4G, 5G, FRA(Future Radio Access), W-CDMA (registered trademark), GSM (registered trademark), CDMA2000, UMB (Ultra Mobile Broadband), IEEE802.11 (Wi-Fi), IEEE802.16 (WiMAX), IEEE802.20, UWB (Ultra-WideBand), or Bluetooth (registered trademark), a system that uses another appropriate system, and/or a next-generation system that is an extension of any of the same.
The orders in the processing procedures, sequences, flowcharts, and the like of the aspects/embodiments described in the present description may be changed as long as no contradictions arise. For example, the methods explained in the present description show various step elements in an exemplified order, and are not limited to the specific order that is shown. The aspects/embodiments described in the present description may also be used alone or in combination, or may also be switched when they are implemented. Furthermore, the notification of predetermined information (e.g., notification of “being X”) is not limited to being performed explicitly, and may also be performed implicitly (for example, notification of the predetermined information is not performed).
The terms “system” and “network” used in the present description can be used in an interchangeable manner.
The information and the parameters described in the present description may also be expressed by absolute values, relative values with respect to a predetermined value, or another type of corresponding information. For example, a radio resource may also be one indicated by an index.
The names used for the above-described parameters are in no way limiting. Furthermore, there may be a case where formulae and the like using these parameters are different from those explicitly disclosed in the present description. Various channels (such as, for example, a PUCCH and a PDCCH) and information elements (such as, for example, a TPC) can be identified by any suitable name, and thus various names assigned to these various channels and information elements are no way limiting. For example, an example was described in which the function of the radio communication apparatus for controlling the transmit power is realized with use of an LTE channel, message, or parameter, but this function can be realized using a 3G or 5G equivalent channel, message, or parameter.
The term “determining” used in the present description may include various types of operations. The term “determining” can include a case where judging, calculating, computing, processing, deriving, investigating, looking up (for example, looking up a table, a data base, or another data structure), or ascertaining is regarded as “determining”. Furthermore, the term “determining” can include a case where receiving (for example, receiving information), transmitting (for example, transmitting information), inputting, outputting, or accessing (for example, accessing data in the memory) is regarded as “determining”. Furthermore, the term “determining” can include a case where resolving, selecting, choosing, establishing, or comparing is regarded as “determining”. In other words, the term “determining” can include a case where some operation is regarded as “determining”.
The present invention may be provided as a flight control method that includes the processing steps performed in flight control system 1 or flight vehicle management apparatus 50. Also, the present invention may be provided as a program for execution in flight vehicle 10 or flight vehicle management apparatus 50. This program may be provided in an aspect of being recorded on a recording medium such as an optical disk, or may be provided in an aspect of being downloaded to a computer via a network such as the Internet and being installed in the computer to become usable, for example.
Software, instructions, and the like may also be transmitted/received via a transmission medium. For example, if software is transmitted from a web site, a server, or another remote source using a wired technology such as a coaxial cable, an optical fiber cable, a twisted-pair wire, or a digital subscriber line (DSL), and/or a wireless technology using infrared light, radio waves, microwaves, or the like, the definition of the transmission medium will include the wired technology and/or the wireless technology.
Information, signals, and the like described in the present description may also be expressed using any of various different technologies. For example, data, an instruction, a command, information, a signal, a bit, a symbol, a chip, and the like that may be mentioned throughout the entire description above may also be expressed by an electric voltage, an electric current, an electromagnetic wave, a magnetic field or a magnetic particle, an optical field or a photon, or an arbitrary combination thereof.
Note that the terms described in the present description and/or the terms needed for understanding the present description may also be replaced by terms that have the same or similar meaning. For example, a channel and/or a symbol may also be a signal. Furthermore, a signal may also be a message. Furthermore, a component carrier (CC) may also be referred to as a carrier frequency, a cell, or the like.
All references to elements that have been given names such as “first” and “second” in the present description do not overall limit the number of such elements or the orders thereof. Such names may be used in the present description as a convenient method for distinguishing between two or more elements. Accordingly, references to first and second elements are not intended to mean that only two elements can be employed, or that the first element is required to come before the second element in some sort of manner.
The “means” in the configurations of the above-described apparatuses may be replaced by “unit”, “circuit”, “device”, or the like.
The terms “including”, “comprising”, and other forms thereof are intended to be comprehensive as long as they are used in the present description or the claims, similar to the term “being provided with”. Furthermore, the term “or” used in the present description or the claims is intended not to be exclusive OR.
In the entirety of the present disclosure, when articles are added through translation, for example, as “a”, “an”, and “the” in English, these articles also denote the plural form unless it is clear otherwise from the context.
While the present invention has been described in detail, it would be obvious to those skilled in the art that the present invention is not limited to the embodiments explained in the present description. The present invention can be implemented as corrected and modified aspects without departing from the spirit and scope of the present invention that are defined by the description of the claims. Accordingly, the present description aims to illustrate examples and is not intended to restrict the present invention in any way.
1. flight control system
10. flight vehicle
20, 30. radio communication apparatus
201. CPU
202. ROM
203. RAM
204. auxiliary storage apparatus
205. communication IF
50. flight vehicle management apparatus
51. tracking unit
52. specification unit
53. assignment unit
501. CPU
502. ROM
503. RAM
504. auxiliary storage apparatus
505. communication IF
Number | Date | Country | Kind |
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2018-073047 | Apr 2018 | JP | national |
Filing Document | Filing Date | Country | Kind |
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PCT/JP2019/012468 | 3/25/2019 | WO | 00 |