KR20180054391A - Method for handover operation and method for control transfer operation - Google Patents

Abstract

Disclosed are a handover method and a control transfer method considering dynamic allocation and management methods of channels. According to one embodiment of the present invention, the handover method comprises the steps of: setting a channel for handover to an unmanned aerial station and a ground station; measuring a channel currently in use by the unmanned aerial station and reporting a measurement result to the ground station; requesting the handover to at least one of a control station and a CNPC network based on the measurement result by the ground station; determining whether the handover will be operated by at least one of the control station and the CNPC network; and commanding the handover to the unmanned aerial station by at least one of the control station and the CNPC network based on whether the handover will be operated.

Description

[0001] METHOD FOR HANDOVER OPERATION AND METHOD FOR CONTROL TRANSFER OPERATION [0002]

The following embodiments relate to a handover method and a control transfer method.

It includes all the components necessary for the entire flight, including unmanned aerial vehicle (UAV), pilotless aircraft or drone, as well as a control communication system for takeoff / cruising, flight control, landing / Unmanned Aircraft Systems (UAS) or Remotely Piloted Aircraft Systems (RPAS).

These UASs consist of UAVs, UAVs, and data links. The data link is a wireless data link between the ground station and the UAV. The UAS data link can be largely divided into UAS ground control and non-payload communication (CNPC) data link and UAS mission link.

A mission data link is a link for carrying data related to mission performance and is generally broader than a CNPC data link. On the other hand, the CNPC link is composed of a pilot / ATC relay link and a UAS control link as a link for conveying data related to UAV flight control, UAS status monitoring, and CNPC link management. The pilot / ATC relay link is a communication link for relaying voice and data between the ATC and the pilot through the UAV, and the UAS control link is used to transmit safety control related information between the pilot and the UAV Link. In case of UAS control link, it can be divided into Telecommand (TC) link and Telemetry (TM) link. TC link can be classified into flight control information, all UAV control information required for safety flight Is the uplink that transmits from the ground pilot to the UAV, and the TM link is the UAV position, altitude, speed, UAS system operation mode and status, navigation assistance data, detection and avoidance related trace, weather radar, To the pilot of the aircraft.

The frequency for the unmanned terrestrial CNPC link is mainly considered as the C (5030-5091 MHz) band allocated to the new dedicated band in WRC-12, and the L (L) 960-1164 MHz) bands may be considered in the aeronautical mobile service. In the C band, the effect of frequency interference with the existing system and the multipath delay spread are small. On the other hand, there is a disadvantage that the directional antenna must be considered for ensuring the link margin and the Doppler effect is five times larger than the L band. On the other hand, the low-frequency band distributed to other aeronautical mobile services such as the L-band has better propagation characteristics than the C-band (L band has 14 dB lower propagation loss than the C band) Equipment, ADS-B (Automatic Dependent Surveillance-Broadcast), and TACAN (Tactic Air Navigation System) are operated in a congested manner, there is a problem in securing the frequency and a large multipath delay spread. Therefore, it is expected that the pre-established C band will be considered as the base link of the terrestrial CNPC and the lower frequency band (eg L or UHF band) will be used to increase the CNPC link availability for unmanned safety navigation. Of course, you can use them in reverse or independently.

Next, terrestrial CNPC link connection types are P2P (Point-to-Point) type and P2MP (Point-to-MultiPoint) type. The P2P type is a concept in which one GRS forms a data link with one UA, which is a type that has been mainly considered in a conventional unmanned aerial vehicle system. On the other hand, in the P2MP type, one GRS forms a data link with a plurality of UAs. In the P2MP type, the GRSs are connected to the network to support the GRS handover. Both P2P type and P2MP type GRS can be connected to the network to provide continuous communication service for UAV control such as GRS handover, or it can be constructed as a single GRS type. Typically, P2P type is built as a single GRS type, and P2MP type is expected to be network based GRS construction. The network-based P2MP type, which can form a communication link with a large number of UAVs at the same time, is expected to be considered as a next generation CNPC link, and the related technology of the P2MP type UAS CNPC system is still insufficient.

In addition, in order to operate the existing P2P type UAS CNPC system, a channel for CNPC must be allocated. In the conventional method, when the UAS CNPC system is registered in the Spectrum Authority (SA), the channel is fixed for a long time The channel assigned to a specific UAS CNPC system is difficult to use in another UAS CNPC system.

Therefore, UAV CNPC system (UAV CNPC system) is operated so as to enable efficient utilization of communication frequency resources for UAV control that can efficiently operate a large number of UAVs in a limited UAV control dedicated frequency band in order to stabilize operation of UAV and increase demand of UAV Is required.

In order to stabilize operation of UAV and increase demand of UAV, it is necessary to design and operate UAV control communication system that can efficiently operate a large number of UAVs in a limited frequency range of UAV control. The frequency bureau does not allocate a specific frequency to a specific CNPC system in a fixed manner. Instead, the frequency bureau manages the frequency in real time and dynamically allocates it only when the UAS CNPC system is operated. And the UAV CNPC system should support such dynamic channel allocation and management.

There is a need for a handover method and a control transfer method for a UAV communication system suitable for such a dynamic channel allocation and management method. The present invention proposes a handover and control right transfer method considering a channel allocation and management method dynamically performed in a frequency bureau.

According to an embodiment of the present invention, there is provided a handover method including: setting a channel for handover to an unmanned station and a ground station; measuring a channel currently being used by the unmanned station and reporting the measurement result to the ground station; Requesting a handover to at least one of a control center and a CNPC network based on the measurement result; and determining whether the at least one handover is determined based on the determination result, And instructing the mobile station to perform a handover.

The method may further include setting an initial channel to the URI and the ground station to connect the wireless link.

The setting may be performed after the connecting step.

The commanding step may include the step of the at least one instructing the handover to the unlicensed station via the ground station.

The method may further include, based on the command, performing the handover to the channel for handover by the UAV, and reporting the handover completion to the at least one.

The reporting of the handover completion may include reporting the handover completion to the at least one station via the ground station.

The setting step may be performed after the determining step.

The handover method according to an embodiment includes the steps of setting a first channel to the second ground station, measuring the second channel by the unmanned station and reporting the measurement result to the first ground station, Requesting a handover to at least one of a control center and a CNPC network based on the measurement result; and determining whether the at least one handover is determined based on the determination result, And instructing the mobile station to perform a handover.

The first channel may be a handover channel, and the second channel may be a currently used channel.

The setting step may include setting a first channel to the UAV and the second ground station.

The step of reporting the measurement result may include reporting the measurement result when the signal quality of the second channel is less than a reference value.

Wherein the step of instructing comprises the steps of: requesting a handover to the second ground station by the at least one based on whether the handover is determined; responding to the handover request to the second ground station by the second ground station; And the at least one commanding the handover to the URI based on the response of the second ground station.

The step of requesting handover to the second ground station may include providing at least one of security setting information to be used when the second ground station and the unmanned aerial station communicate with each other.

The method may further include the step of the second terrestrial station and the unmanned aerial station using the security setting information.

The method may further comprise setting an initial channel to the URI and the first ground station to connect the wireless link.

The method may further comprise, based on the command, the UAV performing a handover to the first channel and reporting the handover completion to the at least one party.

Wherein reporting the handover completion comprises: sending at least one of the control communication data to the unlicensed station; and performing the handover to the first channel based on the control communication data . ≪ / RTI >

The transmitting may comprise the at least one transmitting the control communication data to the unmanned aerial station via the second ground station.

Reporting the handover completion may include reporting the handover completion to the at least one unlicensed station via the second ground station.

The method further comprising the steps of: if the at least one requests handover to the second ground station, the at least one transmitting information necessary for synchronization acquisition to the second ground station; and if the unmanned station requires And performing handover based on the information.

The first channel and the second channel may be channels for handover.

The method may further comprise transmitting the measurement signal for handover decision to the at least one unmanned aerial station.

The step of reporting the measurement result may include reporting the measurement result when the signal quality of the first channel and the second channel is better than the currently used channel.

Wherein the step of transmitting the measurement signal comprises the steps of: the at least one requesting the second ground station to determine a measurement signal transmission time point; and in response to the measurement signal transmission time determination request, And determining a signal transmission for measurement.

The step of determining transmission of the measurement signal may comprise the step of the second ground station determining transmission of the measurement signal based on the downlink channel information of the unmanned aerial station.

Wherein the step of transmitting the measurement signal comprises the steps of: at least one of the at least one requesting the measurement of the signal transmission time point to the UAV; and in response to the measurement signal transmission time determination request, And determining signal transmission.

The step of determining transmission of the measurement signal may comprise determining the signal transmission for measurement using the GNSS position information for the UAV or the received signal strength for the first ground station.

According to an embodiment of the present invention, there is provided a control allocation method comprising: setting a channel for handover to a second ground station; measuring a currently used channel and reporting a measurement result; Requesting handover to the first control center on the basis of whether or not the handover is determined; determining whether the first control center responds to the request in order to control the controllability; Requesting the second control station to transfer control to the second control station, and the second control station requesting the second ground station to prepare for communication with the handover channel in response to the request of the control transfer, , And when the second control center notifies the first control center of the start of the transfer of control, the first notification point notifies the unmanned station of a handover command And, and a step of the UAV station is handed over to a channel for the handover in response to the command.

The step of reporting the measurement result may include the step of measuring the currently used channel by the UAV and reporting the measurement result to the first ground station, and the step of determining whether to perform the handover based on the measurement result And requesting handover to the first control station based on whether or not the first ground station determines handover.

The step of reporting the measurement result may include the step of the second terrestrial station measuring the currently used channel and reporting the measurement result to the second control station.

The method may further include the step of the second control center requesting the security setting information to the unmanned aerial station, and the unmanned aerial station responding to the request of the security setting information.

The step of requesting the security setting information may be performed after performing the handover.

Wherein the step of requesting the security setting information includes requesting security setting information to the UAV through the second ground station, and the step of responding to the request of the security setting information comprises: And responding to a request for security configuration information.

FIG. 1 illustrates an example of a relationship and information exchange with a peripheral system for stable operation of a UAV in a UAV CNPC system according to an exemplary embodiment.
Figure 2 shows another example of the relationship and information exchange between peripheral systems for stable operation of UAV in a UAV CNPC system according to an embodiment.
3 is a diagram for explaining an example of an operation in which a UAV CNPC system performs a handover in the same cell.
4 is a diagram for explaining another example of the operation in which the UAV CNPC system performs handover in the same cell.
5 is a view for explaining an example of an operation in which a UAV CNPC system performs inter-cell handover.
6 is a diagram for explaining another example of the operation in which the UAV CNPC system performs inter-cell handover.
FIG. 7 illustrates an operation in which the second ground station shown in FIG. 6 performs measurement signal transmission for handover determination.
FIG. 8 illustrates an operation in which the UAV shown in FIG. 6 performs measurement signal transmission for handover determination.
FIG. 9 is a diagram for explaining an example of an operation for determining a transmission time point of a measurement signal for a handover decision by the UAV shown in FIG.
FIG. 10 is a view for explaining another example of the operation for determining the transmission time point of the measurement signal for the handover decision by the UAV shown in FIG.
FIG. 11 is a diagram for explaining an operation for determining signal transmission for measurement by the UAV shown in FIG. 10; FIG.
12 is a diagram for explaining an example of an operation in which a control center performs control transfer.
13 is a diagram for explaining another example of an operation in which a control center performs control transfer.
14 is a diagram for explaining another example of an operation in which the control center performs control transfer.

It is to be understood that the specific structural or functional descriptions of embodiments of the present invention disclosed herein are presented for the purpose of describing embodiments only in accordance with the concepts of the present invention, May be embodied in various forms and are not limited to the embodiments described herein.

Embodiments in accordance with the concepts of the present invention are capable of various modifications and may take various forms, so that the embodiments are illustrated in the drawings and described in detail herein. However, it is not intended to limit the embodiments according to the concepts of the present invention to the specific disclosure forms, but includes changes, equivalents, or alternatives falling within the spirit and scope of the present invention.

The terms first, second, or the like may be used to describe various elements, but the elements should not be limited by the terms. The terms may be named for the purpose of distinguishing one element from another, for example without departing from the scope of the right according to the concept of the present invention, the first element being referred to as the second element, Similarly, the second component may also be referred to as the first component.

It is to be understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, . On the other hand, when an element is referred to as being "directly connected" or "directly connected" to another element, it should be understood that there are no other elements in between. Expressions that describe the relationship between components, such as "between" and "between" or "neighboring to" and "directly adjacent to" should be interpreted as well.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. It will be understood that, in this specification, the terms "comprises ", or" having ", and the like are to be construed as including the presence of stated features, integers, But do not preclude the presence or addition of steps, operations, elements, parts, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the meaning of the context in the relevant art and, unless explicitly defined herein, are to be interpreted as ideal or overly formal Do not.

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. However, the scope of the patent application is not limited or limited by these embodiments. Like reference symbols in the drawings denote like elements.

FIG. 1 illustrates an example of a relationship and information exchange with a peripheral system for stable operation of a UAV in a UAV CNPC system according to an exemplary embodiment.

Referring to FIG. 1, a UAV CNPC system 10 includes a spectrum authority (SA) 110, an air traffic control (ATC) 120, a ground control equipment (ATC) 130, a ground CNPC radio system 140, and a CNPC airborne CNPC radio system 150.

The UAV CNPC system 10 may be a UAV CNPC system that controls the UAV 190 in a point-to-point (P2P) type. The UAV 190 may include at least one of a configuration such as Video, Flight Control, and VHF / Radio.

In order to operate the P2P unmanned CNPC system, the control center 130 can request the channel to the SA 110 and receive the channel allocation (K1) from the SA 110.

Next, the control center 130 transmits the ground / unmanned CNPC radio channel assignment information and the information F1 including the state information G1 and the communication data between the ATC 120 and the UAV control data to the CNPC ground station system 140 (H1).

The CNPC ground station system 140 can transmit information A1 including communication data with the ATC 120 and UAV control data to Flight Control and VHF / Radio. The UAV control data may include UAV telemetry and video image data. The information A1 including the communication data with the ATC 120 and the unmanned control data may be substantially the same as the information F1 including the communication data with the ATC 120 and the unmanned control data. In addition, the CNPC ground station system 140 can transmit the CNPC UAV status information (Airborne Radio Status information; B1) to Flight Control.

The CNPC unmanned aerial station system 150 may transmit the information A1 including the communication data with the ATC 120 and the unmanned control data to the CNPC ground station system 140. The CNPC ground station system 140 may transmit the information F1 received from the CNPC UAV system 150 and the CNPC radio channel allocation information and the status information G1 to the control station 130 via the wired or wireless network H1 . The characteristics of the UAV CNPC system 10 will be described below.

The UAV CNPC system 10 can operate in the following link configuration.

1) The UAV CNPC system 10 includes a plurality of ground stations and an unmanned aerial station, and each ground station and the unmanned aerial station can form a one-to-one communication link.

2) If the UAV CNPC system 10 is a standalone system, the UAV CNPC system 10 can extend the coverage by switching the ground station (GRS) of the control station and transferring control.

3) The UAV CNPC system 10 implements an FDMA-based ground station and can support multiple P2P type UAVs in a single ground station.

The uplink channel and the downlink channel of the UAV CNPC system 10 can operate in the following configuration.

1) The UAV CNPC system 10 can operate on an FDMA channel in uplink (ground station -> unmanned station) and downlink (unmanned station -> ground station).

2) The UAV CNPC system 10 can support simultaneous transmission and reception in dual band channels (e.g., L band and C band).

3) The UAV CNPC system 10 may support multiple channel bandwidths (e.g., four Data Classes (DC1) with 30/60/90/120 kHz).

4) The UAV CNPC system 10 supports the number of different supported channel bandwidths per link direction and band.

5) The UAV CNPC system 10 can support DC1, DC2, or DC3 in the uplink and DC1, DC2, DC3, DC4, DC5, or DC6 in the downlink.

6) The UAV of the UAV CNPC system 10 can support simultaneous transmission of two FDMA channels. For example, the two FDMA channels may be one of DC1 to DC4 for UAV control and one of DC5 to DC6 for safety video.

7) The UAV CNPC system 10 can operate in a fixed channel other than channel reallocation and handover.

Figure 2 shows another example of the relationship and information exchange between peripheral systems for stable operation of UAV in a UAV CNPC system according to an embodiment.

2, the UAV CNPC system 20 includes an SA 210, an ATC 220, a control station 230-1 to 230-N, a CNPC ground station system 240, and a CNPC UAV system 250-1 To 250-3). The UAV CNPC system 20 may be a UAV CNPC system that controls the UAVs 290-1 through 290-3 in a Point-to-Multi-Point (P2MP) type. The UAVs 290-1 through 290-3 may include at least one of a configuration such as Video, Flight Control, and VHF / Radio.

The SA 210, the ATC 220, the control stations 230-1 to 230-N, the CNPC ground station system 240, and the CNPC UAV systems 250-1 to 250-3, 110, the ATC 120, the control station 130, the CNPC ground station system 140, and the CNPC unmanned aerial station system 150 may be substantially the same in construction and operation.

Although FIG. 2 shows three CNPC unmanned aerial vehicle systems 250-1 to 250-3 and three unmanned aerial vehicles 290-1 to 290-3 for convenience of explanation, it is not necessarily limited thereto, And can be implemented as a plurality of UAVs.

In order to operate the P2MP type UAV CNPC system, the control stations 230-1 to 230-N can make a channel request to the SA 210 and receive the channel assignment K1 from the SA 210. [

Next, the control stations 230-1 to 230-N transmit the information F1 including the communication data with the ATC 220 and the UAV control data to the CNPC ground station system 240 through the distribution system (H1 to Hn) can do. SA 210 may transmit each unmanned channel assignment information (K1 to Kn) to CNPC ground station system 240. [ The CNPC ground station system 240 transmits information A1 to An including communication data with the ATC 120 and the UAV control data transmitted from the control stations 230-1 to 230-N to the control stations 230-1 to 230- N) to the Flight Control and VHF / Radio of the UAVs 290-1 to 290-3. The UAV control data may include UAV telemetry and video image data. The information A1 to An including the communication data with the ATC 120 and the unmanned control data may be substantially the same as the information F1 to Fn including the communication data with the ATC 120 and the unmanned control data. In addition, the CNPC ground station system 240 can transmit the CNPC UAV status information (B1 to Bn) to the Flight Control.

The CNPC UAV system 250-1 to 250-3 transmits information (A1 to An) including communication data with the ATC 120 relayed from the VHF / UHF Radio and UAV control data to the CNPC ground station system 240 . The CNPC ground station system 240 transmits information (F1 to Fn), CNPC radio channel assignment information, and status information (G1 to Gn) received from a plurality of CNPC UAVs 250-1 to 250-3 to a wired / (H1 to Hn) to the corresponding control stations 230-1 to 230-N.

The control communication service for safe operation provided by the UAV CNC system 20 between the control stations 230-1 to 230-N and the UAVs 290-1 to 290-3 is performed in the case of uplink or downlink can be different. For example, in the case of the uplink, the control communication service for safe operation includes at least one of Telecommand information, ATC Relay information, and NavAid setting information. In the downlink case, the control communication service for safe operation includes telemetry information, ATC relay Information, NavAid information, DAA Target information, Weather Radar information, Safety take-off landing video information, and Emergency video information. The ATC Relay information may include ATC voice and data relay information.

The UAV CNPC system 20 can define and provide various types of service classes to provide various services according to the channel capacity. The channel capacity may be the CNPC channel capacity for the UAVs 290-1 to 290-3.

For example, the CNPC UAV system 250-1 to 250-3 can provide various service classes according to the allocated channel bandwidth or channel capacity by defining the service class as shown in Table 1 in case of the uplink. Also, the CNPC UAV system 250-1 to 250-3 can provide various service classes according to the allocated channel bandwidth or channel capacity by defining a service class as shown in Table 2 in the case of downlink.

The services provided by the CNPC UAV stations 250-1 to 250-3 include telecommand information (uplink, ground station, and unmanned aerial station) and telemetry information (downlink , Unmanned aerial station -> ground station). In addition, at least one of TC / TM data, ATC relay information, NavAid information, DAA target information, Weather radar information, and video information may be further included, depending on the capabilities of the terrestrial and stationary stations and the allocated channel capacity or bandwidth.

The CNPC UAV system 250-1 to 250-3 transmits video services (safety takeoff and landing video information and / or emergency video information) that can be considered in takeoff and landing and emergency situations to a single band of a separate downlink channel For example, the C-band for controlling the UAV). That is, the CNPC UAV system 250-1 to 250-3 transmits one of the Service Classes of Service Classes 1 to 4 and one of the Service Classes 5 to 6 to the C-band Lt; RTI ID = 0.0 > channel < / RTI >

The UAV CNPC system 20 can operate in a dual band so that the link meets 99.999% usage. For example, the CNPC unmanned aerial platform systems 250-1 through 250-3 may operate in the dual band of the C and L bands allocated for UAV control. The UAV CNPC system 20 can transmit the same information or other information in the dual band. When the CNPC UAV system 250-1 to 250-3 transmit the same information, the signal level diversity gain between the L and C bands can be obtained in the physical layer, and the C band and L band A different bandwidth can be allocated from the SA 210 to the mobile station.

At this time, the C band can be utilized for the UAV CNPC with the entire frequency band of 61 MHz as the UAV exclusive frequency band. For example, the CNPC UAV system 250-1 to 250-3 can transmit at least one of TC / TM data, ATC relay information, DAA target information, and Weather radar information in the C band.

In the L band, there may be interference with other aeronautical radio devices. For example, the CNPC UAV system 250-1 to 250-3 can transmit TC / TM data in the L band. The characteristics of the UAV CNPC system 20 will be described below.

The UAV CNPC system 20 can operate in the following link configuration.

1) The UAV CNPC system 20 may include a plurality of ground stations simultaneously supporting a plurality of UAVs.

2) When the UAV CNPC system 20 is connected to the network, the UAV CNPC system 20 can extend the coverage through inter-terrestrial handover.

3) The UAV CNPC system 20 can implement a TDM-based ground station to support multiple UAVs in one ground station.

The uplink channel and the downlink channel of the UAV CNPC system 20 can operate in the following configuration.

1) The UAV CNPC system 20 can operate on the TDM channel in the uplink (ground station -> unmanned aerial station).

2) The UAV CNPC system 20 can allocate different TDM time slots for each unmanned station and distinguish the unmanned station according to the TDM time slot.

3) The UAV CNPC system 20 can allocate the frequency and channel bandwidth (number of TDM slots) of the ground station fixedly. The UAV CNPC system 20 can change the number of TDM slots when performing a long-term update.

4) The UAV CNCP system 20 can flexibly change the number and location of slots allocated to the UAV communicating with the corresponding ground station, thereby supporting multiple UAVs simultaneously and efficiently supporting channel change in the cell.

5) The UAV CNPC system 20 can operate on the FDMA channel in the downlink (unmanned station -> ground station).

6) The UAV CNPC system 20 can support simultaneous transmission and reception in dual band channels (e.g., L band and C band).

7) The UAV CNPC system 20 can support multiple channel bandwidths (e.g., eight channel bandwidths with 90/180/270/360/450/540/630/720 kHz).

8) The UAV CNPC system 20 can support different TDM time slot numbers according to the uplink channel bandwidth. For example, the UAV CNPC system 20 can support three slots for 90 kHz, six slots for 180 kHz, and 24 slots for 720 kHz.

9) The UAV CNPC system 20 can support the number of different channel bandwidths per link direction and band. For example, the UAV CNPC system 20 can support 90/180/270/360/450/540/630/720 kHz in the uplink and 30/40/90/120 kHz in the downlink have.

10) The UAV of the UAV CNPC system 20 can support simultaneous transmission of two FDMA channels. For example, the two FDMA channels may be one of DC1 to DC4 for UAV control and one of DC5 to DC6 for safety video.

11) The UAV CNPC system 20 can operate in a fixed channel other than channel reassignment and handover.

Hereinafter, a handover method and a control right transfer method of the UAV CNPC system 10 or 20 will be described.

3 is a diagram for explaining an example of an operation in which a UAV CNPC system performs a handover in the same cell.

Referring to FIG. 3, the UAV CNPC system may be implemented as the UAV CNPC system 10 shown in FIG. 1 or the UAV CNPC system 20 shown in FIG. The UAV CNPC system includes a control station or CNPC network 330, a ground station 340, and an unmanned aerial station 350. The control station, the ground station 340 and the UAV 350 are connected to the control stations 130 and 230-1 to 230-N shown in Figs. 1 and 2, the CNPC ground station systems 140 and 240, and the CNPC unmanned aerial station system 150 and 250-1 through 250-3) may be substantially the same in construction and operation. The CNPC network may be a communication network formed between the control station and the ground station 340. For example, the CNPC network may perform a handover using the identity of the control station and the ground station 340.

The unmanned aerial station 350 and the ground station 340 can perform radio link connection with each other through channel setting and initial connection. The UAV 350 and the ground station 340 can set a frequency for handover and set a channel for handover. At this time, the UAV 350 and the ground station 340 can establish a handover channel after the wireless link performs the connection.

When the UAV CNPC system performs handover in the same cell, the UAV 350 measures the quality of the currently used channel and the CN or the CNPC network 330 determines the handover based on the measured quality . The quality of the currently used channel measured by the UAV 350 may be quality based on signal quality.

The UAV 350 may report the measurement results to the ground station 340 if the quality (e.g., signal quality) measured by the UAV 350 is less than or equal to a predetermined threshold. At this time, the UAV 350 can periodically report the measurement result. The UAV station 350 may report the measurement results to the ground station 340 based on a predetermined period. The UAV 350 may be set to periodically report the measurement results to the ground station 340 even if the signal quality is above the reference value.

The ground station 340 can request handover to the control center or the CNPC network 330 based on the measurement result.

The control center or the CNPC network 330 may determine whether to hand over in response to the handover request. When the control center or the CNPC network 330 determines a handover, the control center or the CNPC network 330 may send a handover command to the ground station 340.

In response to the handover command, the ground station 340 may forward the handover command to the UAV 350 and change the transmission / reception setting to the handover channel.

In response to the handover command, the UAV 350 can change the transmission / reception setting from the currently used channel to the handover channel. The UAV 350 may transmit a handover complete message to the changed channel.

The ground station 340 may receive a handover complete message on a channel allocated for handover. The ground station 340 can report the handover completion to the control center or the CNPC network 330 and complete the handover procedure.

When performing UAV control communication in the UAV CNPC system, the control center or the CNPC network 330 can perform communication by allocating two primary channels and two secondary channels in the C and L bands. The control center or the CNPC network 330 can determine whether or not the handover is performed based on the channel having the worse signal quality among the Primary and Secondary.

4 is a diagram for explaining another example of the operation in which the UAV CNPC system performs handover in the same cell.

Referring to FIG. 4, the UAV CNPC system may be implemented as the UAV CNPC system 10 shown in FIG. 1 or the UAV CNPC system 20 shown in FIG. The UAV CNPC system includes a control station or CNPC network 430, a ground station 440, and an unmanned aerial station 450. The control station or the CNPC network 430, the ground station 440 and the unmanned aerial station 450 are configured and operated in a manner substantially identical to the control station or CNPC network 330, ground station 340 and unmanned aerial station 350 shown in FIG. . ≪ / RTI >

The UAV CNPC system can exchange (replace) one channel of two channels. For example, the control center or the CNPC network 430 may allocate two channels, Primary and Secondary, for simultaneous transmission and reception, in order to perform communication for UAV control. At this time, when the state of one of the two channels is not good, the control center or the CNPC network 430 may allocate a bad channel to a new channel and perform a handover. The control station or the CNPC network 430 may allocate a channel for handover when the ground station 440 requests handover, and may set a channel for handover.

When the UAV CNPC system performs handover in the same cell, the UAV 450 and the ground station 440 can simultaneously change the setting to a changed channel (for example, a handover channel) and continue communication. At this time, when the ground station 440 transmits the handover command to the UAV 450, the ground station 440 can transmit the timing information for changing to the handover channel. Therefore, the UAV 450 and the ground station 440 can change communication channels for handover at the same timing.

5 is a view for explaining an example of an operation in which a UAV CNPC system performs inter-cell handover.

Referring to FIG. 5, the UAV CNPC system may perform an inter-cell handover. The UAV CNPC system includes a control station or CNPC network 530, a first ground station 540-1, a second ground station 540-2, and an unmanned aerial station 550. The control station, the first ground station 540-1, the second ground station 540-2 and the UAV 550 are connected to the control stations 130 and 230-1 to 230-N shown in FIGS. 1 and 2, Systems 140 and 240, and CNPC unmanned aerial vehicle systems 150 and 250-1 through 250-3, may be substantially identical in construction and operation. The CNPC network may be a communication network formed between the control station and ground stations 540-1 and 540-2. For example, the CNPC network may perform handover using the identity of the control station and ground stations 540-1 and 540-2.

The UAV 550 and the first ground station 540-1 can perform a radio link connection through channel setting and initial connection. The UAV 550 and the second ground station 540-2 can set a frequency for handover and set a channel for handover.

The UAV 550 can measure the quality of the channel currently in use. The quality of the currently used channel measured by the UAV 550 may be quality based on signal quality. If the signal quality is below the reference value, the UAV 550 may report the measurement results to the first ground station 540-1. At this time, the UAV 550 may periodically report the measurement result. The UAV 550 may report the measurement result to the first ground station 540-1 based on a predetermined period. The UAV 550 may be set to periodically report the measurement result to the first ground station 540-1 even if the signal quality is equal to or greater than the reference value

The first ground station 540-1 may request handover to the CN or CNPC network 530 based on the measurement result. The CN or CNPC network 530 may determine whether to hand over in response to a handover request. When the control center or the CNPC network 530 determines handover, the control center or the CNPC network 530 can request a handover to the second ground station 540-2 and receive a response to the handover request.

The control station or the CNPC network 530 may provide security setting information when requesting handover to the second ground station 540-2. The security setting information may be information used in the communication between the UAV 550 and the second ground station 540-2.

The second ground station 540-2 can prepare for transmission / reception to the handover channel. For example, the second ground station 540-2 sets up transmission / reception for the handover channel and prepares for reception of signals of the UAV 550 and / or control communication data of the control center or CNPC network 530 . The second ground station 540-2 may perform transmission on the handover channel when control communication data is received from the control station or the CNPC network 530. [ The control communication data may be the same data that the control station or the CNPC network 530 delivers to the first ground station 540-1.

The control station or the CNPC network 530 may transmit a handover command to the first ground station 540-1 and the first ground station 540-1 may transmit the handover command to the UAV 550. [ The handover command received at the UAV 550 may include security setting information. The UAV 550 can use the security setting information when communicating with the second ground station 540-2.

The UAV 550 may perform a handover in response to a handover command. That is, the UAV 550 can change from the current channel to the handover channel. The unmanned aerial station 350 can transmit a handover complete message to the second ground station 540-2.

The second ground station 540-2 may report handover completion to the control center or the CNPC network 530 in response to the handover complete message. The control station or the CNPC network 530 notifies the first ground station 540-1 of the completion of the handover and the first ground station 540-1 can terminate data transmission and reception with the UAV 550. [

The UAV 550 measures a signal from the second ground station 540-2 for a predetermined time before changing from a channel in use to a channel for handover and outputs a frequency offset, a time offset offset, AGC, and the like can be acquired in advance. Accordingly, when the UAV 550 is changed to a channel for handover and the wireless link is connected, information related to acquisition of the synchronization can be used to acquire synchronization.

When the control station or the CNPC network 530 requests handover to the second ground station 540-2, the UAV 550 may transmit the currently used channel information together. Accordingly, the second ground station 540-2 can perform the receiving operation on the currently used channel of the UAV 550 and acquire the information necessary for acquiring the synchronization in advance.

The first ground station 540-1 and the second ground station 540-2 can transmit the same data to the UAV 550. [ In addition, the first ground station 540-1 and the second ground station 540-2 can always receive the message transmitted by the UAV 550. Therefore, data transmitted and received between the control station or the CNPC network 530 and the UAV 550 may not be lost regardless of the timing (timing) at which the UAV 550 changes the channel for handover.

6 is a diagram for explaining another example of the operation in which the UAV CNPC system performs inter-cell handover.

Referring to FIG. 6, the UAV CNPC system can perform inter-cell handover. The UAV CNPC system includes a control station or CNPC network 630, a first ground station 640-1, a second ground station 640-2, and an unmanned aerial vehicle 650. The control station, the first ground station 640-1, the second ground station 640-2 and the unmanned aerial station 650 are connected to the control stations 130 and 230-1 to 230-N shown in FIGS. 1 and 2, Systems 140 and 240, and CNPC unmanned aerial vehicle systems 150 and 250-1 through 250-3, may be substantially identical in construction and operation. The CNPC network may be a communication network formed between the control station and the ground stations 640-1 and 640-2. For example, the CNPC network can perform handover using the identity of the control station and ground stations 640-1 and 640-2.

Initially, in the UAV CNPC system, only the second ground station 640-2 can set a handover channel. At this time, the second ground station 640-2 can transmit a measurement signal to the control station or the CNPC network 630, the first ground station 640-1, and the UAV 650 for handover determination. The operation of the second ground station 640-2 to transmit the measurement signal will be described later with reference to Figs. 7 and 8. Fig.

The UAV 650 can measure the quality of the handover channel and compare it with the quality of the currently used channel. If the quality of the handover channel is higher than the reference value and the quality is better than the current channel, the UAV 650 can perform the measurement report to the first ground station 640-1. In the case of a measurement report of the UAV 650, periodic measurement reports or periodic measurement reports above or below the reference value may be possible, as described above in FIG.

The first ground station 640-1 may receive the measurement report and operate as described above in Fig. In addition, the control center or the CNPC network 630 may determine whether to perform handover based on the measurement signal.

FIG. 7 illustrates an operation in which the second ground station shown in FIG. 6 performs measurement signal transmission for handover determination.

Referring to FIG. 7, the UAV CNPC system includes a control station or CNPC network 730, a first ground station 740-1, a second ground station 740-2, and an unmanned aerial station 750. The control station or the CNPC network 730, the first ground station 740-1, the second ground station 740-2 and the unmanned aerial station 750 are connected to the control station or CNPC network 630, the first ground station 640-1, the second ground station 640-2, and the UAV 650 may be substantially the same in construction and operation.

The control station or the CNPC network 730 may request the second ground station 740-2 to determine the signal transmission time point for measurement. At this time, the control station or the CNPC network 730 may provide the downlink channel information currently used by the UAV in communication with the first ground station 740-1.

The second ground station 740-2 may transmit a response to the request for determining the signal transmission time point for measurement, and may use the downlink channel information to measure the received signal strength of the channel transmitted by the UAV. The second ground station 740-2 may determine the transmission of the measurement signal when the received signal strength is equal to or greater than the reference value and request the data for transmission of the measurement signal to the control center or the CNPC network 730. [

The control station or the CNPC network 730 may transmit a response to the data request for measurement signal transmission and may also transmit the same data to the second ground station 740-2 as the data to be transmitted to the first ground station 740-1 .

When the second ground station 740-2 receives a response to the data request for measurement signal transmission, it can change the transmission / reception setting to the handover channel.

The control station or the CNPC network 730 may request handover channel measurement to the UAV 750 through the first ground station 740-1 and may transmit handover channel information together. The control center or CNPC network 730 may complete the measurement signal transmission procedure upon receiving a response to the request from the UAV 750. The control station or CNPC network 730 may receive a response to the request through the first ground station 740-1.

The measurement signal transmission data that the control station or the CNPC network 730 transmits to the second ground station 740-2 is the same data as the data to be transmitted to the first ground station 740-1 as described above, Lt; / RTI >

When the second ground station 740-2 uses the predefined data as the signal data for measurement, the second ground station 740-2 does not receive the data for measurement signal transmission from the control center or the CNPC network 730 . Security may be applied to the wireless link between the unmanned aerial station 750 and the ground station 740-1 or 740-2.

When the second ground station 740-2 uses the same data as the data to be transmitted to the first ground station 740-1 as measurement signal data, the second ground station 740-2 transmits the measurement signal transmission data request And the security setting information from the control center or the CNPC network 730 together.

When the second ground station 740-2 considers the soft handover, the same setting information as the security setting applied by the first ground station 740-1 and the UAV 750 is transmitted to the control center or the CNPC network 730) and can be applied.

When the second ground station 740-2 considers hard handover, it may receive and apply the security setting information to be used after the handover from the control center or the CNPC network 730. [

The second ground station 740-2 can measure the channel being used by the UAV 750 in various ways according to the antenna and RF configuration. When the second ground station 740-2 uses a tracking antenna, the UAV can perform measurements in the direction in which the first ground station 740-1 is located in the cell where the UAV currently exists. When the second ground station 740-2 uses an omni-directional antenna, measurement can be performed without any special setting. When the second ground station 740-2 uses a sector antenna, the UAV may perform measurements on the antennas facing the direction of the cell in which the UAV exists. The second ground station 740-2 may periodically perform measurements on the antennas facing the direction of the cell where the UAV is presently present. At this time, if the RF configuration of the second ground station 740-2 supports measurements for multiple antennas at one time, measurements for the antennas may be performed at one time.

The UAV 750 may apply the acquired information such as a frequency offset, a time offset, or an AGC to the receiver while performing handover channel measurement. For example, the UAV 750 may apply information to a receiver when changing from an in-use channel to a handover channel. Thus, the UAV 750 can acquire the reception synchronization.

The second ground station 740-2 can perform the receiving operation on the channel currently used by the UAV 750 until the handover complete message is received from the UAV 750 in the handover channel. When the UAV 750 performs handover, it changes only the channel in the same C band or L band, and the information such as the frequency offset, the time offset, or the AGC acquired from the channels currently used by the UAV 750 To the reception of the channel for the handover so as to immediately acquire the reception synchronization.

FIG. 8 illustrates an operation in which the UAV shown in FIG. 6 performs measurement signal transmission for handover determination.

Referring to FIG. 8, the UAV CNPC system includes a control station or a CNPC network 830, a first ground station 840-1, a second ground station 840-2, and an unmanned aerial station 850. The control station or the CNPC network 830, the first ground station 840-1, the second ground station 840-2 and the unmanned aerial station 850 are connected to the control station or CNPC network 630, the first ground station 640-1, the second ground station 640-2, and the UAV 650 may be substantially the same in construction and operation.

The control center or the CNPC network 830 may request the UAV 850 to determine the signal transmission time point for measurement. For example, the control center or CNPC network 830 may request the UAV 850 to determine the point of time of transmission of the measurement signal via the first ground station 840-1 and receive the response.

The UAV 850 can determine the transmission time point of the measurement signal using the currently used channel state information and / or position information. The UAV 850 can combine the channel state information and the position information to determine the transmission time point of the measurement signal. The control station or the CNPC network 830 may provide information on the manner in which the UAV 850 and the reference value or the like are used to determine when to transmit the signal for measurement. For example, the control center or the CNPC network 830 may provide information to the UAV 850 in response to a request for determining the time of transmission of the measurement signal.

The unmanned aerial station 850 can report an event to the first ground station 840-1 in the event that an event that measurement signal transmission is necessary occurs. In response to the event report, the first ground station 840-1 may request the control station or the CNPC network 830 to transmit the measurement signal. The control station or the CNPC network 830 may instruct the second ground station 840-2 to transmit the measurement signal. When the control station or the CNPC network 830 receives a response to the command from the second ground station 840-2, the control station or the CNPC network 830 sends the first ground station 840-1 The same data as the control data to be transmitted to the mobile station. When the first ground station 840-1 receives a response to the measurement signal transmission request from the control station or the CNPC network 830, the first ground station 840-1 may request the UAV 850 to set up a channel measurement for handover. Thus, the UAV 850 can perform channel measurements.

The measurement signal transmission data that the control station or the CNPC network 830 transmits to the second ground station 840-2 is the same data as the data to be transmitted to the first ground station 840-1 as described above, Lt; / RTI >

When the second ground station 840-2 uses predefined data as signal data for measurement, the second ground station 840-2 does not receive data for measurement signal transmission from the control center or the CNPC network 830 . Security may be applied to the wireless link between the UAV 850 and the ground station 840-1 or 840-2.

When the second ground station 840-2 uses the same data as the data to be transmitted to the first ground station 840-1 as the signal data for measurement, the second ground station 840-2 is connected to the control station or the CNPC network 830, And transmits the measurement signal transmission command and the security setting information together.

When the second ground station 840-2 considers the soft handover, it receives from the control center or the CNPC network 830 the same setting information as the security setting currently applied by the first ground station 840-1 and the unmanned aerial station 850 Can be applied.

When the second ground station 840-2 considers the hard handover, it can receive and apply the security setting information to be used after the handover from the control center or the CNPC network 830. [

7 and 8 illustrate a configuration in which the second ground station 740-2 or the UAV 850 determines a measurement signal transmission time point for convenience of explanation. However, the present invention is not limited to this, (730 or 830) sets a channel for handover, it may directly transmit a measurement signal to the UAV 750 or 850. [

FIG. 9 is a diagram for explaining an example of an operation for determining a transmission time point of a measurement signal for a handover decision by the UAV shown in FIG.

8 and 9, the UAV 850 can utilize the GNSS position information and / or the received signal strength from the currently connected ground station 840-1 or 840-2 to determine the time of signal transmission for measurement have.

When the UAV 850 uses the GNSS location information to determine the time of signal transmission for measurement, the UAV 850 can preset the area 900. [ Area 900 may be a region that initiates a measurement for handover. The UAV 850 may request the transmission of a measurement signal to the control center or the CNPC network 830 when the UAV enters the area 900.

The UAV 850 can monitor the received signal strength when the UAV 850 uses the received signal strength from the ground station 840-1 or 840-2 to determine the time of signal transmission for measurement. The received signal strength may be the intensity of the signal received in the current communication. The UAV 850 can determine the signal transmission for measurement if the received signal strength drops below a certain critical value.

FIG. 10 is a view for explaining another example of the operation for determining the transmission time point of the measurement signal for the handover decision by the UAV shown in FIG. 8, and FIG. 11 is a diagram for explaining the operation of the UAV shown in FIG. And Fig.

8, 10 and 11, the UAV 850 uses the received signal strength from the GNSS position information and the currently connected ground station 840-1 or 840-2 to determine a signal transmission time point for measurement . The UAV 850 transmits an area to the R-1 area 1010, the R-2 area 1020, and the R-1 area 1030 to use the received signal strength from the GNSS location information and the currently connected ground station 840-1 or 840-2. And an R-3 region 1030.

The R-1 region 1010 is the region closest to the current ground station 840-1 or 840-2, and may be an area where handover does not occur. That is, when the UAV is located in the R-1 region 1010, the UAV 850 may not consider the measurement signal transmission.

The R-2 region 1020 may be a region in which handover occurs as the case may be. For example, the UAV 850 can perform a handover when signal quality is poor due to terrain or the like.

The R-3 region 1030 may be an area corresponding to the area 900 shown in FIG. That is, when the UAV is located in the R-3 zone 1030, the UAV 850 can request the measurement station to transmit the measurement signal to the CN or the CNPC network 830.

The UAV 850 can determine the signal transmission for measurement using the GNSS location information and the received signal strength from the currently connected ground station 840-1 or 840-2.

The UAV 850 can receive the current GNSS location information from the GNSS module and receive the received signal strength from the currently connected ground station 840-1 or 840-2. The UAV 850 can confirm the position of the UAV by the current GNSS position information.

The GNSS module may mean hardware capable of performing functions and operations for measuring the GNSS position information, computer program code capable of performing a specific function and operation, or performing a specific function and operation For example, a processor or a microprocessor, on which computer program code may be stored. In other words, the GNSS module may mean a functional and / or structural combination of software to drive hardware and / or hardware to perform the operation of GNSS location information measurement.

If the UAV is currently located in the R-1 region 1010, the UAV 850 may repeat receiving GNSS location information and received signal strength. That is, the GNSS module and the ground station 840-1 or 840-2 can continuously measure the GNSS position information and the received signal strength.

If the UAV is currently located in the R-2 region 1020, the UAV 850 can compare the received signal strength with the threshold. If the received signal strength is greater than the threshold value, the GNSS position information and the received signal strength can be measured again. If the received signal strength is less than the threshold, the UAV 850 can determine the signal transmission for measurement.

When the UAV is currently located in the R-3 region 1030, the UAV 850 can determine transmission of the measurement signal irrespective of the received signal strength.

12 is a diagram for explaining an example of an operation in which a control center performs control transfer.

Referring to FIG. 12, the UAV CNPC system includes a first control station 1230-1, a second control station 1230-2, a first ground station 1240-1, a second ground station 1240-2, 1250). The first control station 1230-1, the second control station 1230-2, the first ground station 1240-1, the second ground station 1240-2, and the unmanned aerial station 1250 are shown in Figs. 1 and 2 May be substantially identical in construction and operation to the CNC ground control stations 130 and 230-1 to 230-N, the CNPC ground station systems 140 and 240, and the CNPC unmanned aerial vehicle systems 150 and 250-1 to 250-3 .

The first control center 1230-1 can make a channel request to the SA (frequency bureau) and receive a channel assignment from the SA. The first ground station 1240-1 and the UAV 1250 may be connected using the assigned channel.

The second control center 1230-2 may request the SA for a channel for UAV transfer and a channel for UAV transfer from the SA. The second control station 1230-2 sets a channel for transferring control of the UAV to the second ground station 1240-2 and provides channel information for transferring the UAV to the first control station 1230-1 .

The unmanned aerial station 1250 can measure the channel currently in use with the first ground station 1240-1. At this time, when the signal quality of the currently used channel is less than the reference value, the UAV 1250 can report the measurement result to the first ground station 1240-1.

In response to the measurement result, the first ground station 1240-1 can request handover to the first control station 1230-1. The first control center 1230-1 may determine the control transfer in response to the handover request.

If the first control center 1230-1 determines the transfer of control, the first control center 1230-1 may request the second control center 1230-2 to start the control transfer.

The second control station 1230-2 may request the second ground station 1240-2 to prepare for a radio link with the UAV and receive a response in response to the start request of the control transfer. Also, the second control center 1230-2 can forward the message of the control transfer process start to the first control center 1230-1. The second ground station 1240-2 can set up a transmission / reception with a handover channel for connection with a UAV and prepare for a wireless link connection. The first control station 1230-1 may communicate the handover command to the UAV 1250 via the first ground station 1240-1 in response to the message of initiating the control transfer procedure.

The UAV 1250 can perform a handover from the currently used channel to the handover channel and transmit the handover complete message to the second ground station 1240-2. The second ground station 1240-2 can report the completion of the handover to the second control center 1230-2. The second control center 1230-2 can transmit the control transfer completion message to the first control center 1230-1. The first control station 1230-1 may transmit a handover completion message to the first ground station 1240-1 and terminate the transmission / reception operation with the unmanned aerial station 1250. [

When the first control center 1230-1 requests the start of the transfer of control right to the second control center 1230-2, the first control center 1230-1 requests the second control center 1230-2, Related setting information applied between the first ground station 1240-1 and the unmanned aerial vehicle 1250 at the same time.

The second control center 1230-2 can update the security key based on the security-related setting information. The security key may be used for wireless link connection between the second ground station 1240-2 and the UAV 1250. [ The second control station 1230-2 may provide the updated security key together with the second ground station 1240-2 in response to the radio link connection preparation request with the unmanned aerial station 1250. [ When the second control station 1230-2 confirms the start of control transfer to the first control station 1230-1, the second ground station 1240-2 and the unmanned aerial station 1250 together transmit security setting information to be used . The UAV 1250 can set security based on the provided security setting information. The first control station 1230-1 may provide the handover command to the UAV 1250 including the security setting information.

13 is a diagram for explaining another example of an operation in which a control center performs control transfer.

Referring to FIG. 13, the UAV CNPC system includes a first control station 1330-1, a second control station 1330-2, a first ground station 1340-1, a second ground station 1340-2, 1350). The first control station 1330-1, the second control station 1330-2, the first ground station 1340-1, the second ground station 1340-2, and the unmanned aerial station 1350 correspond to the first May have substantially the same configuration and operation as the control station 1230-1, the second control station 1230-2, the first ground station 1240-1, the second ground station 1240-2, and the unmanned aerial vehicle 1250 have.

When the first control station 1330-1 and the second control station 1330-2 do not share the security setting, the UAV 1350 and the second ground station 1340-2 perform handover completion You may not want to apply security to your messages.

In response to receiving the handover complete message, the second control station 1330-2 may request security settings to the UAV 1350 via the second ground station 1340-2. The unmanned aerial station 1350 may transmit a security setting response to the second control station 1330-2 via the second ground station 1340-2 in response to the security setting request.

14 is a diagram for explaining another example of an operation in which the control center performs control transfer.

14, the UAV CNPC system includes a first control station 1430-1, a second control station 1430-2, a first ground station 1440-1, a second ground station 1440-2, and an unmanned aerial station 1450). The first control station 1430-1, the second control station 1430-2, the first ground station 1440-1, the second ground station 1440-2, and the unmanned aerial station 1450 correspond to the first May have substantially the same configuration and operation as the control station 1230-1, the second control station 1230-2, the first ground station 1240-1, the second ground station 1240-2, and the unmanned aerial vehicle 1250 have.

The second control station 1430-2 can request the first control station 1430-1 to start the transfer of control based on the measurement result of the second ground station 1440-2.

The first control center 1430-1 can make a channel request to an SA (frequency bureau) and receive a channel assignment from the SA. The first ground station 1440-1 and the unmanned aerial station 1450 may be connected using the assigned channel.

The second control station 1430-2 requests a channel for control transfer of the UAV, and can receive a channel for transferring control of the UAV from the SA. The second control station 1430-2 sets a channel for transferring control of the UAV to the second ground station 1440-2 and provides channel information for transferring the UAV to the first control station 1430-1 .

The first control station 1430-1 may transmit the response to the provided channel information and the downlink channel information used by the current unmanned aerial station 1450 to the second control station 1430-2. The second control station 1430-2 can provide downlink channel information currently used by the UAV 1450 to the second ground station 1440-2. The second ground station 1440-2 may perform measurements on the unmanned station 1450 based on the downlink channel information currently in use.

The second ground station 1440-2 may measure the downlink channel of the UAV 1450. [ The second ground station 1440-2 can measure the downlink channel by measuring the received signal strength. When the received signal strength is equal to or greater than the reference value, the second ground station 1440-2 can perform the measurement result report to the second control station 1430-2. As described above in FIG. 3, the second ground station 1440-2 may perform periodic reporting, or may perform periodic reporting above a reference value.

The second control station 1430-2 may determine the control transfer start request based on the measurement result report and request the first control station 1430-1 to start the transfer of control.

The first control station 1430-1 may determine the control transfer in response to the control transfer start request and request the second control station 1430-2 to start the control transfer process.

The second control station 1430-2 can request the second ground station 1440-2 to prepare for the radio link connection with the unmanned aerial station 1450 and receive the response. Also, the second control station 1430-2 can transmit a confirmation message to the first control station 1430-1 to request the control transfer procedure start request. The second ground station 1440-2 can set up a handover channel transmission / reception in response to the radio link connection preparation request, and prepare for a radio link connection with the unmanned aerial station 1450. [

The first control station 1430-1 can transmit the handover command to the UAV 1450 through the first ground station 1440-1. The UAV 1450 can perform a handover from the currently used channel to the handover channel and transmit the handover complete message to the second ground station 1440-2. When the second ground station 1440-2 receives the handover complete message, the second ground station 1440-2 can report the handover completion to the second control station 1430-2. When the second control station 1430-2 receives the handover completion report, the second control station 1430-2 can inform the first control station 1430-1 of the completion of the control transfer. The first control station 1430-1, which has received the completion of the control transfer, can notify the first ground station 1440-1 of the completion of the handover. Accordingly, the first ground station 1440-1 can terminate the transmission / reception operation with the UAV 1450. [

When the first control station 1430-1 requests the second control station 1430-2 to start the control transfer, the first control station 1430-1 requests the second control station 1430-2, Related setting information applied between the first ground station 1440-1 and the unmanned aerial station 1450 at present.

The second control center 1430-2 can update the security key based on the security-related setting information. The security key may be used for wireless link connection between the second ground station 1440-2 and the UAV 1450. [ The second control station 1430-2 may provide the updated security key together with the second ground station 1440-2 in response to the radio link connection preparation request with the unmanned aerial station 1450. [ When the second control station 1430-2 confirms the start of the transfer of the control right to the first control station 1430-1, the second ground station 1440-2 and the unmanned aerial station 1450 together transmit security setting information to be used . The UAV 1450 can set security based on the provided security setting information. The first control station 1430-1 may provide the handover command to the unmanned aerial station 1450 including the security setting information.

When the first control station 1430-1 and the second control station 1430-2 do not share the security setting, the UAV 1450 and the second ground station 1440-2 perform handover completion immediately after handover You may not want to apply security to your messages.

The operation after the second control station 1430-2 receives the handover complete message from the second ground station 1440-2 may be as described with reference to FIG.

The configuration described above can be used for handover of UAV communication that may occur during UAV operation and control transfer between UAVs that control UAV. In addition, the above-described configurations can be applied to P2P-type and P2MP-type UAV CNPC systems and, when applied to a P2MP type UAV CNPC system, can support multiple UAVs at the same time.

The apparatus described above may be implemented as a hardware component, a software component, and / or a combination of hardware components and software components. For example, the apparatus and components described in the embodiments may be implemented within a computer system, such as, for example, a processor, a controller, an arithmetic logic unit (ALU), a digital signal processor, a microcomputer, a field programmable gate array (FPGA) , A programmable logic unit (PLU), a microprocessor, or any other device capable of executing and responding to instructions. The processing device may execute an operating system (OS) and one or more software applications running on the operating system. The processing device may also access, store, manipulate, process, and generate data in response to execution of the software. For ease of understanding, the processing apparatus may be described as being used singly, but those skilled in the art will recognize that the processing apparatus may have a plurality of processing elements and / As shown in FIG. For example, the processing unit may comprise a plurality of processors or one processor and one controller. Other processing configurations are also possible, such as a parallel processor.

The software may include a computer program, code, instructions, or a combination of one or more of the foregoing, and may be configured to configure the processing device to operate as desired or to process it collectively or collectively Device can be commanded. The software and / or data may be in the form of any type of machine, component, physical device, virtual equipment, computer storage media, or device , Or may be permanently or temporarily embodied in a transmitted signal wave. The software may be distributed over a networked computer system and stored or executed in a distributed manner. The software and data may be stored on one or more computer readable recording media.

The method according to an embodiment may be implemented in the form of a program command that can be executed through various computer means and recorded in a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, and the like, alone or in combination. The program instructions to be recorded on the medium may be those specially designed and configured for the embodiments or may be available to those skilled in the art of computer software. Examples of computer-readable media include magnetic media such as hard disks, floppy disks and magnetic tape; optical media such as CD-ROMs and DVDs; magnetic media such as floppy disks; Magneto-optical media, and hardware devices specifically configured to store and execute program instructions such as ROM, RAM, flash memory, and the like. Examples of program instructions include machine language code such as those produced by a compiler, as well as high-level language code that can be executed by a computer using an interpreter or the like. The hardware devices described above may be configured to operate as one or more software modules to perform the operations of the embodiments, and vice versa.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. For example, it is to be understood that the techniques described may be performed in a different order than the described methods, and / or that components of the described systems, structures, devices, circuits, Lt; / RTI > or equivalents, even if it is replaced or replaced.

Therefore, other implementations, other embodiments, and equivalents to the claims are also within the scope of the following claims.

Claims (33)

A method for performing handover in a same cell,
Setting a channel for handover to an unmanned aerial station and a ground station;
Measuring the channel currently in use by the UAV and reporting the measurement result to the ground station;
Requesting handover from the ground station to at least one of a control center and a CNPC network based on the measurement result;
Determining whether the at least one handover is a handover; And
Wherein said at least one commanding handover to said unlicensed station based on the determined handover status
/ RTI >
The method according to claim 1,
Establishing an initial channel in the UAV and the ground station and connecting a wireless link
The handover method further comprising:
3. The method of claim 2,
Wherein the setting step comprises:
Wherein the handover method is performed after the connecting step.
The method according to claim 1,
Wherein said commanding step comprises:
Said at least one commanding handover to said unmanned aerial station via said ground station
/ RTI >
The method according to claim 1,
Performing the handover to the handover channel based on the command and reporting the handover completion to the at least one station
The handover method further comprising:
6. The method of claim 5,
Wherein reporting the handover completion comprises:
Wherein said unmanned aerial station reports said handover completion to said at least one via said ground station
/ RTI >
The method according to claim 1,
Wherein the setting step comprises:
Wherein the handover method is performed after the determining step.
A method for performing an inter-cell handover from a first ground station to a second ground station,
Setting a first channel to the second ground station;
Measuring the second channel by the UAV and reporting the measurement result to the first ground station;
Requesting handover from the ground station to at least one of a control center and a CNPC network based on the measurement result;
Determining whether the at least one handover is a handover; And
Wherein said at least one commanding handover to said unlicensed station based on the determined handover status
/ RTI >
9. The method of claim 8,
Wherein the first channel is a handover channel and the second channel is a currently used channel.
9. The method of claim 8,
Wherein the setting step comprises:
Setting a first channel to the UAV and the second ground station
/ RTI >
10. The method of claim 8,
Reporting the measurement result comprises:
Reporting the measurement result if the signal quality of the second channel is less than or equal to a reference value
/ RTI >
9. The method of claim 8,
Wherein said commanding step comprises:
The at least one requesting handover to the second ground station based on the determined handover;
The second ground station responding to a handover request to the second ground station; And
Said at least one commanding a handover to said unlicensed station based on a response of said second ground station
/ RTI >
13. The method of claim 12,
Wherein the requesting handover to the second ground station comprises:
Said at least one providing security setting information to be used when said second ground station and said unmanned aerial station communicate
/ RTI >
14. The method of claim 13,
Wherein said second ground station and said unmanned aerial station communicate using said security setting information
The handover method further comprising:
9. The method of claim 8,
Establishing an initial channel in the URI and the first ground station and connecting a wireless link
The handover method further comprising:
9. The method of claim 8,
Performing a handover to the first channel based on the command and reporting the handover completion to the at least one station
The handover method further comprising:
17. The method of claim 16,
Wherein reporting the handover completion comprises:
Said at least one transmitting control communication data to said unlicensed station; And
Performing a handover to the first channel by the UAV based on the control communication data
/ RTI >
18. The method of claim 17,
Wherein the transmitting comprises:
Said at least one transmitting said control communication data via said second ground station to said unmanned aerial station
/ RTI >
17. The method of claim 16,
Wherein reporting the handover completion comprises:
Wherein the unmanned aerial station reports the handover completion to the at least one through the second ground station
/ RTI >
13. The method of claim 12,
If the at least one requesting handover to the second ground station, the at least one transmitting information necessary for synchronization acquisition to the second ground station; And
Performing a handover based on information required for acquiring the synchronization of the UAV;
The handover method further comprising:
9. The method of claim 8,
Wherein the first channel and the second channel are channels for handover.
22. The method of claim 21,
Transmitting at least one measurement signal for handover decision to the UAV;
The handover method further comprising:
22. The method of claim 21,
Reporting the measurement result comprises:
Reporting the measurement result when the signal quality of the first channel and the second channel is better than the currently used channel
/ RTI >
23. The method of claim 22,
Wherein the step of transmitting the measurement signal comprises:
The at least one requesting the second ground station to determine a transmission time point of a measurement signal; And
In response to the measurement signal transmission time point determination request, the second ground station determining the measurement signal transmission
/ RTI >
25. The method of claim 24,
Wherein the determining of the measurement signal transmission comprises:
The second ground station determining the transmission of the measurement signal based on downlink channel information of the unmanned aerial station
/ RTI >
23. The method of claim 22,
Wherein the step of transmitting the measurement signal comprises:
The at least one requesting a determination of the time point of signal transmission for measurement to the unlicensed station; And
In response to the measurement signal transmission timing determination request, the unmanned station determining transmission of the measurement signal
/ RTI >
27. The method of claim 26,
Wherein the determining of the measurement signal transmission comprises:
Determining the signal transmission for measurement using the GNSS position information for the UAV or the received signal strength for the first ground station
/ RTI >
In the method of performing the transfer of control from the first control center to the second control center,
Setting a channel for handover to a second ground station;
Measuring a currently used channel and reporting a measurement result;
Determining whether to perform a handover based on the measurement result;
Requesting handover to the first control center based on whether the handover is determined;
Determining whether the first control center responds to the request to transfer control;
The first control center requests control transfer to the second control center based on the determined control transfer privilege;
The second control station requesting the second ground station to prepare for communication with the handover channel in response to the request of the transfer of control;
When the second control center notifies the first control center of the start of the transfer of control, the first notice instructs the unmanned station to perform the handover; And
Performing a handover to the handover channel in response to the command by the UAV;
A control transfer method involving.
29. The method of claim 28,
Reporting the measurement result comprises:
Measuring the currently used channel by the UAV and reporting the measurement result to the first ground station
Lt; / RTI >
Wherein the step of determining whether to perform the handover based on the measurement result comprises:
Requesting handover to the first control station based on whether or not the first ground station determines handover
A control transfer method involving.
29. The method of claim 28,
Reporting the measurement result comprises:
Measuring the currently used channel by the second ground station and reporting the measurement result to the second control station
A control transfer method involving.
29. The method of claim 28,
The second control center requesting security setting information to the UAV; And
The URI station responding to the request for the security configuration information
A control transfer method further comprising:
32. The method of claim 31,
Wherein the step of requesting the security setting information comprises:
Wherein the handover is performed after the step of performing the handover.
32. The method of claim 31,
Wherein the step of requesting the security setting information comprises:
Requesting the unauthorized station for security setting information through the second ground station
Lt; / RTI >
Wherein responding to the request for security configuration information comprises:
The step of responding to the request of the security setting information through the second ground station
A control transfer method involving.

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