U.S. patent application number 15/394151 was filed with the patent office on 2017-07-27 for methods and procedures for dynamic channel assignment and change in unmanned aircraft system (uas) control and non-payload communication.
The applicant listed for this patent is Electronics and Telecommunications Research Institute. Invention is credited to Jae Young AHN, Hee Wook KIM.
Application Number | 20170215178 15/394151 |
Document ID | / |
Family ID | 59360814 |
Filed Date | 2017-07-27 |
United States Patent
Application |
20170215178 |
Kind Code |
A1 |
KIM; Hee Wook ; et
al. |
July 27, 2017 |
METHODS AND PROCEDURES FOR DYNAMIC CHANNEL ASSIGNMENT AND CHANGE IN
UNMANNED AIRCRAFT SYSTEM (UAS) CONTROL AND NON-PAYLOAD
COMMUNICATION
Abstract
A dynamic channel assignment method includes receiving, at a
ground control station (GCS), assignment of a first communication
channel set from a spectrum authority before takeoff of the
unmanned aircraft; receiving, at the GCS, assignment of a second
communication channel set when the unmanned aircraft is to move
from a first area using the first communication channel set to a
second area using the second communication channel set due to a
flight plan of the unmanned aircraft after takeoff of the unmanned
aircraft; and after the unmanned aircraft enters the second area,
maintaining, at the GCS, the first communication channel set when
the unmanned aircraft reenters the first area due to the flight
plan, and returning, at the GCS, the first communication channel
set to the spectrum authority when the unmanned aircraft does not
reenter the first area due to the flight plan.
Inventors: |
KIM; Hee Wook; (Daejeon,
KR) ; AHN; Jae Young; (Daejeon, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Electronics and Telecommunications Research Institute |
Daejeon |
|
KR |
|
|
Family ID: |
59360814 |
Appl. No.: |
15/394151 |
Filed: |
December 29, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G08G 5/0013 20130101;
H04W 72/048 20130101; G08G 5/0069 20130101; H04W 72/0453
20130101 |
International
Class: |
H04W 72/04 20060101
H04W072/04; G08G 5/00 20060101 G08G005/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 27, 2016 |
KR |
10-2016-0009969 |
Claims
1. A dynamic channel assignment method of a point-to-point (P2P)
unmanned aircraft system (UAS) comprising a spectrum authority, a
ground control station (GCS), a ground radio station (GRS), and an
unmanned aircraft, the method comprising: receiving, at the GCS,
assignment of a first communication channel set for communication
between the GCS and the unmanned aircraft from the spectrum
authority before takeoff of the unmanned aircraft; receiving, at
the GCS, assignment of a second communication channel set before
the unmanned aircraft enters a second area when the unmanned
aircraft is to move from a first area in which the first
communication channel set is available to the second area in which
the second communication channel set different from the first
communication channel set is available due to a flight plan of the
unmanned aircraft after takeoff of the unmanned aircraft;
performing, at the GCS, communication with the unmanned aircraft
using the second communication channel set when the unmanned
aircraft enters the second area; and maintaining, at the GCS, the
first communication channel set when the unmanned aircraft reenters
the first area from the second area due to the flight plan of the
unmanned aircraft, and returning, at the GCS, the first
communication channel set to the spectrum authority when the
unmanned aircraft does not reenter the first area due to the flight
plan of the unmanned aircraft.
2. The method of claim 1, further comprising: returning, at the
GCS, the first communication channel set to the spectrum authority
and receiving assignment of a third communication channel set
available in a third area from the spectrum authority when the
unmanned aircraft enters the third area due to the flight plan of
the unmanned aircraft.
3. The method of claim 1, further comprising: monitoring, at the
GCS, a link state of a communication channel set in use; and
changing, at the GCS, the communication channel set by returning
the communication channel set in use to the spectrum authority and
by receiving assignment of a new communication channel set when the
link state of the communication channel set in use does not satisfy
a reference value.
4. The method of claim 3, wherein the communication channel set
includes a primary channel and a backup channel, and the primary
channel and the backup channel are selected from different
frequency bands, respectively.
5. The method of claim 4, wherein the changing of the communication
channel set comprises initially changing one of the primary channel
and the backup channel included in the communication channel set
and subsequently changing a remaining one thereof.
6. The method of claim 1, further comprising: providing, at the
GCS, information of a communication channel set assigned from the
spectrum authority to the GRS; and verifying, at the GRS, whether
the communication channel set is assigned from the spectrum
authority, based on information of the communication channel
set.
7. The method of claim 6, wherein the spectrum authority further
provides information indicating that the communication channel set
is assigned from the spectrum authority when assigning the
communication channel set to the GCS, information of the
communication channel set provided from the GCS to the GRS includes
information indicating that the communication channel set is
assigned from the spectrum authority, and the GRS verifies whether
the communication channel set is assigned from the spectrum
authority based on information indicating that the communication
channel set is assigned from the spectrum authority.
8. A dynamic channel assignment method of a point-to-multipoint
(P2MP) unmanned aircraft system (UAS) comprising a spectrum
authority, a ground control station (GCS), a ground radio station
(GRS) supporting a plurality of unmanned aircrafts, and an unmanned
aircraft, the method comprising: transmitting, at the GRS,
information of the GRS to the spectrum authority, and receiving
assignment of an uplink frequency set from the spectrum authority;
registering, at the spectrum authority, the uplink frequency set
and information of the GRS to a database of the spectrum authority;
receiving, at the GCS, assignment of a first communication channel
set for communication between the GCS and the unmanned aircraft
from the spectrum authority before takeoff of the unmanned
aircraft; receiving, at the GCS, assignment of a second
communication channel set before the unmanned aircraft enters a
second area when the unmanned aircraft is to move from a first area
in which the first communication channel set is available to the
second area in which the second communication channel set different
from the first communication channel set is available due to a
flight plan of the unmanned aircraft after takeoff of the unmanned
aircraft; performing, at the GCS, communication with the unmanned
aircraft using the second communication channel set when the
unmanned aircraft enters the second area; and maintaining, at the
GCS, the first communication channel set when the unmanned aircraft
reenters the first area from the second area due to the flight plan
of the unmanned aircraft, and returning, at the GCS, the first
communication channel set to the spectrum authority when the
unmanned aircraft does not reenter the first area due to the flight
plan of the unmanned aircraft.
9. The method of claim 8, further comprising: returning, at the
GCS, the first communication channel set to the spectrum authority
and receiving assignment of a third communication channel set
available in a third area from the spectrum authority when the
unmanned aircraft enters the third area due to the flight plan of
the unmanned aircraft.
10. The method of claim 8, further comprising: monitoring, at the
GCS, a link state of a communication channel set in use; and
changing, at the GCS, the communication channel set by returning
the communication channel set in use to the spectrum authority and
by receiving assignment of a new communication channel set when the
link state of the communication channel set in use does not satisfy
a reference value.
11. The method of claim 10, wherein the receiving the assignment of
the communication channel set comprises receiving an approval of a
GRS used at the GCS from the spectrum authority, and receiving
assignment of a time slot in an uplink frequency assigned to the
GRS and a downlink frequency as the communication channel set, and
the changing of the communication channel set comprises changing,
at the GCS, the downlink frequency of the communication channel set
and the time slot of the uplink frequency.
12. The method of claim 10, wherein the communication channel set
includes a primary channel and a backup channel, and the primary
channel and the backup channel are selected from different
frequency bands, respectively.
13. The method of claim 12, wherein the changing of the
communication channel set comprises initially changing one of the
primary channel and the backup channel included in the
communication channel set and subsequently changing a remaining one
thereof.
14. The method of claim 8, further comprising: providing, at the
GCS, information of a communication channel set assigned from the
spectrum authority to the GRS; and verifying, at the GRS, whether
the communication channel set is assigned from the spectrum
authority, based on information of the communication channel
set.
15. The method of claim 14, wherein the spectrum authority further
provides information indicating that the communication channel set
is assigned from the spectrum authority when assigning the
communication channel set to the GCS, information of the
communication channel set provided from the GCS to the GRS includes
information indicating that the communication channel set is
assigned from the spectrum authority, and the GRS verifies whether
the communication channel set is assigned from the spectrum
authority based on information indicating that the communication
channel set is assigned from the spectrum authority.
16. A distributed channel assignment method of a point-to-point
(P2P) unmanned aircraft system (UAS) comprising a spectrum
authority, a ground control station (GCS), a ground radio station
(GRS) supporting a plurality of unmanned aircrafts, and an unmanned
aircraft, the method comprising: selecting, at the GCS, available
channels for communication with the unmanned aircraft based on
information provided from the spectrum authority; requesting, at
the GCS, the spectrum authority for assigning a single channel
among the available channels; verifying, at the spectrum authority,
whether the requested channel is available in a flight area of the
unmanned aircraft, and determining whether to approve the requested
channel; and assigning, at the spectrum authority, the requested
channel to the GCS when the requested channel is determined to be
approved.
17. The method of claim 16, further comprising: providing, at the
spectrum authority, an assignment database and an interference
analysis algorithm for determining whether to assign the channel to
the GCS, prior to selecting at the GCS, the available channels,
wherein the selecting comprises analyzing, at the GCS, performing
interference analysis between frequency channels using the
interference analysis algorithm and selecting a communication
channel compatible with an existing communication channel present
in a current flight area of the unmanned aircraft during flight of
the unmanned aircraft.
18. The method of claim 16, wherein the requesting comprises
providing, at the GCS, at least one of communication link waveform
information including a bandwidth of the requested channel, a
maximum transmission power, and a receiver sensitivity, a GRS to be
used at the GCS, and a transceiver location and an antenna pattern
of the unmanned aircraft.
19. The method of claim 16, further comprising: providing, at the
GCS, communication channel link state information between the GCS
and the unmanned aircraft to the spectrum authority; and updating,
at the spectrum authority, the interference analysis algorithm
based on the communication channel link state information.
20. The method of claim 19, further comprising: notifying, at the
spectrum authority, the GCS that the channel assignment is
disallowed if the channel assignment is impossible; receiving, at
the GCS, the updated interference analysis algorithm from the
spectrum authority, reselecting an available channel using the
updated interference analysis algorithm, and requesting again the
spectrum authority for the reselected available channel; and
assigning, at the spectrum authority, the channel to the GCS when
the requested channel is determined to be approved.
Description
CROSS-REFERENCE TO RELATED APPLICATION(S)
[0001] This application claims the priority benefit of Korean
Patent Application No. 10-2016-0009969 filed on Jan. 27, 2016, in
the Korean Intellectual Property Office, the disclosure of which is
incorporated herein by reference for all purposes.
BACKGROUND
[0002] 1. Field
[0003] One or more example embodiments relate to methods and
procedures for dynamic channel assignment and change for
controlling an unmanned aircraft, and more particularly, to methods
and procedures for dynamically assigning and changing a
communication channel in a point-to-point (P2P) and
point-to-multipoint (P2MP) unmanned aircraft control communication
system in order to efficiently use and manage a limited unmanned
aircraft control spectrum in the national airspace.
[0004] 2. Description of Related Art
[0005] All of constituent elements required for an entire flight
process, including a control communication system, such as
takeoff/cruise, flight control, landing/retrieval, etc., together
with an unmanned aircraft are exclusively referred to as an
unmanned aircraft system (UAS) or a remotely piloted aircraft
system (RPAS).
[0006] The UAS includes unmanned aircraft ground control equipment,
an unmanned aircraft, and a data link. The data link refers to a
wireless data link between a ground radio station (GRS) and the
unmanned aircraft, and may be classified into a USA ground control
and non-payload communication (CNPC) data link and a UAS payload
data link.
[0007] A payload data link is a link used to transfer data
associated with payload, and is generally a wideband compared to a
CNPC data link. The CNPC data link is a link used to transfer data
associated with unmanned aircraft flight control, UAS state
monitoring, and CNPC link management, and includes a pilot/air
traffic control (ATC) relay link and a UAS control link.
[0008] The pilot/ATC relay link is a communication link used to
relay voice and data between a pilot and an ATC through the
unmanned aircraft, and the UAS control link is a link used to
transfer control information associated with navigation safety
between the pilot and the unmanned aircraft.
[0009] The UAS control link may be classified into a telecommand
(TC) link and a telemetry (TM) link. The TC link is an uplink used
to transfer flight orbit control information, all of unmanned
aircraft system control information required for safe flight, etc.,
from a pilot on the ground to the unmanned aircraft, and the TM
link is a downlink used to transfer a location, altitude, and speed
of the unmanned aircraft, UAS system operation mode and state,
navigation support data, tracking associated with detection and
avoidance, a weather radar, video information, etc., from the
unmanned aircraft to the pilot on the ground.
[0010] A frequency for the unmanned aircraft ground CNPC data link
generally considers a C (5030 to 5091 MHz) band, which is
distributed as a new exclusive band in WRC-12. In addition, a band
distributed for an aeronautical mobile service may be considered,
such as an L (960 to 1164 MHz) band of which a standard is prepared
to be available for an aeronautical mobile service in WRC-12.
[0011] In the C band, a frequency jamming effect with an existing
system and a multipath delay spread are relatively small On the
contrary, a directional antenna needs to be used to secure a link
margin and a Doppler effect of the C band is great by five times
compared to that of the L band.
[0012] A low frequency band distributed for an aeronautical mobile
service, such as the L band, has a relatively excellent propagation
characteristic compared to the C band. The L band has a relatively
low propagation loss of about 14 dB compared to the C band.
However, existing navigation systems, such as distance measurement
equipment (DME), automatic dependent surveillance-broadcast
(ADS-B), a tactical air Navigation system (TACAN), etc., are
operated in the confusion. Thus, a frequency securement is
difficult and a multipath delay spread is great.
[0013] In general, the secured C band may be considered as a basic
link of ground CNPC and the low frequency band, for example, the L
band, an ultra high frequency (UHF), etc., may be used to increase
the availability of the CNPC data link for navigation safety of the
unmanned aircraft.
[0014] A connection type of the ground CNPC data link may include a
point-to-point (P2P) type and a network-based point-to-multipoint
(P2MP) type.
[0015] In the P2P type, a single ground control station (GCS)
directly forms a data link with the unmanned aircraft. The P2P type
is generally considered in an existing UAS.
[0016] In the network-based P2MP type, ground radio stations (GRSs)
are connected to a network and each GCS exchanges information with
the unmanned aircraft through a ground network and a GRS.
[0017] The P2MP type capable of simultaneously forming a
communication link with a plurality of unmanned aircrafts and also
forming a national network is to be considered as a next generation
CNPC data link in order to expand the application of public and
private unmanned aircrafts. Technology associated with such a P2MP
UAS CNPC system has not been actively proposed.
[0018] Also, a CNPC channel is to be assigned to operate an
existing P2P UAS CNPC system. In an existing scheme, a spectrum
authority statically assigns a channel during a relatively long
time, for example, generally, 1 year or more, when registering a
UAS CNPC system. Thus, a channel that is assigned to a specific UAS
CNPC system may not be readily used at another UAS CNPC system.
[0019] Accordingly, there is a need for technology for efficiently
using communication frequency resources for controlling an unmanned
aircraft that may efficiently operate a plurality of unmanned
aircrafts in a limited frequency band exclusive for controlling an
unmanned aircraft in order to achieve the stable operation of the
unmanned aircraft and expand the demand for unmanned aircrafts.
SUMMARY
[0020] An aspect of at least one example embodiment is to provide a
user with a new method and procedure for dynamically assigning and
changing a channel in an unmanned aircraft system (UAS) control and
non-payload communication (CNPC) system that may be applicable to a
point-to-multipoint (P2MP) CNPC system capable of enhancing a use
of limited CNPC frequency and supporting a plurality of unmanned
aircrafts.
[0021] Technical subjects to be achieved herein are not limited to
the aforementioned subjects and one of ordinary skill in the art
may understand other technical subjects not described herein from
the following description.
[0022] According to an aspect, there is provided a dynamic channel
assignment method of a point-to-point (P2P) UAS including a
spectrum authority, a ground control station (GCS), a ground radio
station (GRS), and an unmanned aircraft, the method including
receiving, at the GCS, assignment of a first communication channel
set for communication between the GCS and the unmanned aircraft
from the spectrum authority before takeoff of the unmanned
aircraft; receiving, at the GCS, assignment of a second
communication channel set before the unmanned aircraft enters a
second area when the unmanned aircraft is to move from a first area
in which the first communication channel set is available to the
second area in which the second communication channel set different
from the first communication channel set is available due to a
flight plan of the unmanned aircraft after takeoff of the unmanned
aircraft; performing, at the GCS, communication with the unmanned
aircraft using the second communication channel set when the
unmanned aircraft enters the second area; and maintaining, at the
GCS, the first communication channel set when the unmanned aircraft
reenters the first area from the second area due to the flight plan
of the unmanned aircraft, and returning, at the GCS, the first
communication channel set to the spectrum authority when the
unmanned aircraft does not reenter the first area due to the flight
plan of the unmanned aircraft.
[0023] The dynamic channel assignment method may further include
returning, at the GCS, the first communication channel set to the
spectrum authority and receiving assignment of a third
communication channel set available in a third area from the
spectrum authority when the unmanned aircraft enters the third area
due to the flight plan of the unmanned aircraft.
[0024] The dynamic channel assignment method may further include
monitoring, at the GCS, a link state of a communication channel set
in use; and changing, at the GCS, the communication channel set by
returning the communication channel set in use to the spectrum
authority and by receiving assignment of a new communication
channel set when the link state of the communication channel set in
use does not satisfy a reference value.
[0025] The communication channel set may include a primary channel
and a backup channel, and the primary channel and the backup
channel may be selected from different frequency bands,
respectively.
[0026] The changing of the communication channel set may include
initially changing one of the primary channel and the backup
channel included in the communication channel set and subsequently
changing a remaining one thereof.
[0027] The dynamic channel assignment method may further include
providing, at the GCS, information of a communication channel set
assigned from the spectrum authority to the GRS; and verifying, at
the GRS, whether the communication channel set is assigned from the
spectrum authority, based on information of the communication
channel set.
[0028] The spectrum authority may further provide information
indicating that the communication channel set is assigned from the
spectrum authority when assigning the communication channel set to
the GCS, information of the communication channel set provided from
the GCS to the GRS may include information indicating that the
communication channel set is assigned from the spectrum authority,
and the GRS may verify whether the communication channel set is
assigned from the spectrum authority based on information
indicating that the communication channel set is assigned from the
spectrum authority.
[0029] According to another aspect, there is provided a dynamic
channel assignment method of a P2MP UAS including a spectrum
authority, a GCS, a GRS supporting a plurality of unmanned
aircrafts, and an unmanned aircraft, the method including
transmitting, at the GRS, information of the GRS to the spectrum
authority, and receiving assignment of an uplink frequency set from
the spectrum authority; registering, at the spectrum authority, the
uplink frequency set and information of the GRS to a database of
the spectrum authority; receiving, at the GCS, assignment of a
first communication channel set for communication between the GCS
and the unmanned aircraft from the spectrum authority before
takeoff of the unmanned aircraft; receiving, at the GCS, assignment
of a second communication channel set before the unmanned aircraft
enters a second area when the unmanned aircraft is to move from a
first area in which the first communication channel set is
available to the second area in which the second communication
channel set different from the first communication channel set is
available due to a flight plan of the unmanned aircraft after
takeoff of the unmanned aircraft; performing, at the GCS,
communication with the unmanned aircraft using the second
communication channel set when the unmanned aircraft enters the
second area; and maintaining, at the GCS, the first communication
channel set when the unmanned aircraft reenters the first area from
the second area due to the flight plan of the unmanned aircraft,
and returning, at the GCS, the first communication channel set to
the spectrum authority when the unmanned aircraft does not reenter
the first area due to the flight plan of the unmanned aircraft; and
returning, at the GCS, the first communication channel set to the
spectrum authority and receiving assignment of a third
communication channel set available in a third area from the
spectrum authority when the unmanned aircraft enters the third area
due to the flight plan of the unmanned aircraft.
[0030] The dynamic channel assignment method may further include
monitoring, at the GCS, a link state of a communication channel set
in use; and changing, at the GCS, the communication channel set by
returning the communication channel set in use to the spectrum
authority and by receiving assignment of a new communication
channel set when the link state of the communication channel set in
use does not satisfy a reference value.
[0031] The receiving the assignment of the communication channel
set may include receiving an approval of a GRS used at the GCS from
the spectrum authority, and receiving assignment of a time slot in
an uplink frequency assigned to the GRS and a downlink frequency as
the communication channel set, and the changing of the
communication channel set may include changing, at the GCS, the
downlink frequency of the communication channel set and the time
slot of the uplink frequency.
[0032] The communication channel set may include a primary channel
and a backup channel, and the primary channel and the backup
channel may be selected from different frequency bands,
respectively.
[0033] The changing of the communication channel set may include
initially changing one of the primary channel and the backup
channel included in the communication channel set and subsequently
changing a remaining one thereof.
[0034] The dynamic channel assignment method may further include
providing, at the GCS, information of a communication channel set
assigned from the spectrum authority to the GRS; and verifying, at
the GRS, whether the communication channel set is assigned from the
spectrum authority, based on information of the communication
channel set.
[0035] The spectrum authority may further provide information
indicating that the communication channel set is assigned from the
spectrum authority when assigning the communication channel set to
the GCS, information of the communication channel set provided from
the GCS to the GRS may include information indicating that the
communication channel set is assigned from the spectrum authority,
and the GRS may verify whether the communication channel set is
assigned from the spectrum authority based on information
indicating that the communication channel set is assigned from the
spectrum authority.
[0036] According to another aspect, there is provided a distributed
channel assignment method of a P2P UAS including a spectrum
authority, a GCS, a GRS supporting a plurality of unmanned
aircrafts, and an unmanned aircraft, the method including
selecting, at the GCS, available channels for communication with
the unmanned aircraft based on information provided from the
spectrum authority; requesting, at the GCS, the spectrum authority
for assigning a single channel among the available channels;
verifying, at the spectrum authority, whether the requested channel
is available in a flight area of the unmanned aircraft, and
determining whether to approve the requested channel; and
assigning, at the spectrum authority, the requested channel to the
GCS when the requested channel is determined to be approved.
[0037] The distributed channel assignment method may further
include providing, at the spectrum authority, an assignment
database and an interference analysis algorithm for determining
whether to assign the channel to the GCS, prior to selecting, at
the GCS, the available channels. The selecting may include
analyzing, at the GCS, performing interference analysis between
frequency channels using the interference analysis algorithm and
selecting a communication channel compatible with an existing
communication channel present in a current flight area of the
unmanned aircraft during flight of the unmanned aircraft.
[0038] The requesting may include providing, at the GCS, at least
one of communication link waveform information including a
bandwidth of the requested channel, a maximum transmission power,
and a receiver sensitivity, a GRS to be used at the GCS, and a
transceiver location and an antenna pattern of the unmanned
aircraft.
[0039] The distributed channel assignment method may further
include providing, at the GCS, communication channel link state
information between the GCS and the unmanned aircraft to the
spectrum authority; and updating, at the spectrum authority, the
interference analysis algorithm based on the communication channel
link state information.
[0040] The distributed channel assignment method may further
include notifying, at the spectrum authority, the GCS that the
channel assignment is disallowed if the channel assignment is
impossible; receiving, at the GCS, the updated interference
analysis algorithm from the spectrum authority, reselecting an
available channel using the updated interference analysis
algorithm, and requesting again the spectrum authority for the
reselected available channel; and assigning, at the spectrum
authority, the channel to the GCS when the requested channel is
determined to be approved.
[0041] The requesting again the reselected available channel may
include providing, at the GCS, at least one of the changed flight
plan of the unmanned aircraft, communication link waveform
information including a bandwidth of the requested channel, a
maximum transmission power, and a receiver sensitivity, a GRS to be
used at the GCS, and a transceiver location and an antenna pattern
of the unmanned aircraft in response to a change in the flight
plane of the unmanned aircraft, the communication link waveform
information, the GRS to be used at the GCS, and the transceiver
location and the antenna pattern of the unmanned aircraft.
[0042] According to some example embodiments, it is possible to
provide a user with a new method and procedure for dynamically
assigning and changing a channel in a UAS CNPC system that may be
applicable to a P2MP CNPC system capable of enhancing a use of
limited CNPC frequency and simultaneously supporting a plurality of
unmanned aircrafts.
[0043] Additional aspects of example embodiments will be set forth
in part in the description which follows and, in part, will be
apparent from the description, or may be learned by practice of the
disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0044] These and/or other aspects, features, and advantages of the
invention will become apparent and more readily appreciated from
the following description of example embodiments, taken in
conjunction with the accompanying drawings of which:
[0045] FIGS. 1A through 1C illustrate examples of a new channel
assignment procedure after channel assignment and channel return in
a point-to-point (P2P) unmanned aircraft control and non-payload
communication (CNPC) system according to example embodiments;
[0046] FIG. 2 illustrates an example of a procedure of assigning
and changing a channel in a P2P unmanned aircraft CNPC system
according to example embodiments;
[0047] FIGS. 3A through 3C illustrate examples of a new channel
assignment procedure after general assignment and channel return in
a point-to-multipoint (P2MP) unmanned aircraft CNPC system
according to example embodiments;
[0048] FIG. 4 illustrates an example of a procedure of assigning
and changing a channel in a P2MP unmanned aircraft CNPC system
according to example embodiments;
[0049] FIG. 5A illustrates an example of a distributed channel
assignment procedure in a P2P type according to example
embodiments;
[0050] FIG. 5B illustrates an example of a centralized channel
assignment procedure in a P2P type according to example
embodiments;
[0051] FIG. 6A illustrates an example of a distributed channel
assignment procedure in a P2MP type according to example
embodiments;
[0052] FIG. 6B illustrates an example of a centralized channel
assignment procedure in a P2MP type according to example
embodiments; and
[0053] FIG. 7 is a block diagram illustrating a computing system to
execute a dynamic channel assignment and change method and
procedure for controlling an unmanned aircraft according to example
embodiments.
DETAILED DESCRIPTION
[0054] Hereinafter, some example embodiments will be described in
detail with reference to the accompanying drawings. Regarding the
reference numerals assigned to the elements in the drawings, it
should be noted that the same elements will be designated by the
same reference numerals, wherever possible, even though they are
shown in different drawings. Also, in the description of
embodiments, detailed description of well-known related structures
or functions will be omitted when it is deemed that such
description will cause ambiguous interpretation of the present
disclosure.
[0055] Terms, such as first, second, A, B, (a), (b), and the like,
may be used herein to describe components. Each of these
terminologies is not used to define an essence, order or sequence
of a corresponding component but used merely to distinguish the
corresponding component from other component(s). For example, a
first component may be referred to as a second component, and
similarly the second component may also be referred to as the first
component. Unless otherwise defined, all terms, including technical
and scientific terms, used herein have the same meaning as commonly
understood by one of ordinary skill in the art to which this
disclosure pertains. Terms, such as those defined in commonly used
dictionaries, are to be interpreted as having a meaning that is
consistent with their meaning in the context of the relevant art,
and are not to be interpreted in an idealized or overly formal
sense unless expressly so defined herein.
[0056] The example embodiments relate to methods and procedures in
which a spectrum authority dynamically assigns and changes a
channel to a next generation uplink time division multiple access
(TDMA)/downlink frequency division multiple access (FDMA)
point-to-multipoint (P2MP) unmanned aircraft control communication
system including a ground ratio station (GRS) supporting a
plurality of unmanned aircrafts as well as an existing P2P unmanned
aircraft control communication system based on distributed and
centralized channel assignment methods capable of efficiently
assigning and managing a limited unmanned aircraft control spectrum
through the spectrum authority. The proposed methods and procedures
may be applicable to other systems having a similar operation
concept as well as an unmanned aircraft control and non-payload
communication (CNPC) system.
[0057] Hereinafter, dynamic channel assignment methods and
procedures between a spectrum authority and a UAS CNPC system
including a ground control station (GCS) and P2P and P2MP GRSs.
[0058] A channel assignment procedure of the P2P unmanned aircraft
CNPC system will be described with reference to FIGS. 1A through
1C.
[0059] FIGS. 1A through 1C illustrate examples of a new channel
assignment procedure after channel assignment and channel return in
a P2P unmanned aircraft CNPC system according to example
embodiments.
[0060] FIG. 1A illustrates an example of assigning a single
frequency channel set to the P2P unmanned aircraft CNPC system
according to example embodiments.
[0061] Referring to FIG. 1A, in operation S111, a GCS requests a
spectrum authority for assigning a single CNPC channel set
available in an airspace volume present in a flight path of an
unmanned aircraft before takeoff.
[0062] In operation S122, in response to the request, the spectrum
authority assigns a frequency channel to the GCS based on a CNPC
channel set unit.
[0063] Here, the frequency channel to be assigned may include a
center frequency and a channel bandwidth, and the channel set may
include a primary channel or a backup channel
[0064] Whether to constitute the channel set using the primary
channel or using the primary channel and the backup channel may be
determined at the CCS based on a channel support capability of the
unmanned aircraft CNPC system, a current CNPC spectrum use state,
and the like. If necessary, the spectrum authority may recommend a
configuration of the channel set to the GCS.
[0065] That is, in operation A111, the GCS may request the spectrum
authority for assigning a single primary channel or a single
primary channel and a single backup channel as a CNPC channel for
operating the unmanned aircraft based on a flight plan, an unmanned
aircraft/GRS capability, a current CNPC channel use state, and the
like.
[0066] In operation S113, in response to the channel assignment,
the GCS transmits, to the spectrum authority, a response that
verifies the channel assignment.
[0067] FIG. 1B illustrates an example of assigning an additional
frequency set to the P2P unmanned aircraft CNPC system after
assigning a frequency set according to example embodiments.
[0068] Operations S121 through S123 of FIG. 1B are the same as
operations S111 through S113 of FIG. 1A.
[0069] A CNPC channel set includes information about airspace
volume in which a corresponding channel is available. When a flight
plan to another airspace volume in which the assigned CNPC channel
set is unavailable is included in a flight path of the unmanned
aircraft, the flight to the other airspace volume is to be
prepared.
[0070] Referring to FIG. 1B, in operation S124, the GCS requests
the spectrum assignment for assigning another CNPC channel set
available for the flight to the other airspace volume.
[0071] In operation S125, in response to the request, the spectrum
assignment assigns a frequency channel to the GCS based on a CNPC
channel set unit.
[0072] In operation S126, in response to the channel assignment,
the GCS transmits, to the spectrum assignment, a response that
verifies the channel assignment.
[0073] FIG. 1C illustrates an example in which the P2P unmanned
aircraft CNPC system returns the assigned frequency set and
receives assignment of a new frequency set according to example
embodiments.
[0074] If three or more airspace volumes each in which a different
CNPC channel set is available are present in the flight path of the
unmanned aircraft, the GCS may use three CNPC channel sets in the
flight path.
[0075] The GCS may continuously request the spectrum authority for
assigning a CNPC channel set. However, since a CNPC spectrum is
limited, a single unmanned aircraft CNPC system may be limited to
maintain maximum two CNPC channel sets.
[0076] To secure another channel set in a state in which two CNPC
channel sets are secured, the GCS needs to return one of the
existing channel sets to the spectrum authority and then request
assignment of another channel set.
[0077] A backup frequency channel may be assigned simultaneously
together with a primary frequency channel or may be assigned
independently. That is, only the backup frequency channel between
the primary frequency channel and the backup frequency channel may
be changed.
[0078] For example, when the unmanned aircraft is flying in the
second airspace volume, the GCS may return an existing single
channel used in the first airspace volume and may request the
spectrum authority for assigning a CNPC channel available in the
third airspace volume.
[0079] Referring to FIG. 1C, in operation S131, the GCS notifies
the spectrum authority of a channel return schedule, and requests
the spectrum authority for assigning a new channel
[0080] That is, the GCS notifies the spectrum authority that the
GCS is to return the existing single channel used in the first
airspace volume, and requests the spectrum authority for assigning
a CNPC channel available in the third airspace volume.
[0081] In operation S132, the spectrum authority notifies the GCS
that the new channel is assignable.
[0082] In operation S133, the GCS returns the maintained channel to
the spectrum authority.
[0083] In operation S134, the spectrum authority verifies the
channel return and assigns the new channel to the GCS.
[0084] In operation S135, the GCS receives assignment of the new
channel and transmits, to the spectrum authority, a response that
verifies the channel assignment.
[0085] In the above procedure, if two or more frequency bands for
CNPC are present, one of channels in one of the two or more
frequency bands may be selected as a primary frequency channel and
one of channels in another one thereof may be selected as a backup
frequency channel.
[0086] A backup band is used to enhance the CNPC link availability,
and a backup channel and a primary frequency channel are not
selected from a single CNPC band due to a nonlinearity issue of an
amplifier of a transmitter for a GRS and an unmanned aircraft, and
the like.
[0087] For example, in the case of C band and L band assigned for
CNPC in WRC-12, a primary channel may be selected only from the C
band by using the C band as a primary band and a backup channel may
be selected only from the L band by using the L band as a backup
band.
[0088] Also, in operations S131 through S135, when changing the
primary channel, the channel bandwidth as well as the center
frequency may also be changed.
[0089] However, during the flight of the unmanned aircraft, change
of the channel frequency and the bandwidth is not recommended based
on a service rate required at the unmanned aircraft in real time.
Thus, only in the case of requesting assignment of another primary
channel so that the unmanned aircraft may move to the airspace
volume in which the primary frequency channel currently in use is
unavailable, change of the frequency band may also be
requested.
[0090] In general, when requesting a bandwidth for the primary
channel before takeoff, the bandwidth may be assigned based on a
CNPC service to be used during the entire flight of the unmanned
aircraft. Thus, when changing the primary channel, change of the
channel bandwidth may not be considered generally.
[0091] However, when entering another airspace volume, a relatively
great bandwidth may be requested to be assigned. In this case, a
relatively large amount of time may be used to receive channel
assignment from the spectrum authority. Thus, a relatively small
bandwidth may be requested to be assigned based on only a required
service. In this case, change of the bandwidth may also be
considered in addition to change of the channel frequency.
[0092] Two CNPC channel sets that a single unmanned aircraft CNPC
system may simultaneously maintain are for different airspace
volumes that do not allow the same CNPC channel based on a
frequency reuse policy.
[0093] Due to a limited CNPC spectrum, a single unmanned aircraft
CNPC system does not simultaneously maintain two CNPC channel sets
each available in a single airspace volume.
[0094] Accordingly, change of the primary channel and the backup
channel in a specific airspace volume may proceed through a
procedure of returning an existing channel and receiving assignment
of a new channel. In this case, the primary channel and the backup
channel may not be simultaneously changed in order to prevent CNPC
link outage between return of the existing channel and use of the
new channel
[0095] Meanwhile, frequency change of the primary channel or the
backup channel in the specific airspace volume is performed
generally when a CNPC backup link is in a poor state. When the link
state is poor during monitoring the link state of the primary
channel or the backup channel, for example, monitoring a bit error
rate (BER), signal interference and noise ratio (SINR), a link loss
alert, and the like, it is possible to request the spectrum
authority for another primary or backup frequency channel
[0096] As described above, a relatively small bandwidth may be
requested to be assigned when changing the primary channel On the
contrary, a bandwidth of the backup frequency channel may be
differently changed depending on whether a backup channel is a
backup channel for enhancing the link availability by
simultaneously transmitting and receiving the primary channel and
the backup channel, and a backup channel for enhancing the link
availability by switching to the backup channel in response to
primary channel link loss.
[0097] To simultaneously transmit and receive the primary channel
and the backup channel, the bandwidth of the primary channel is to
be same as that of the backup channel Accordingly, in the case of
the backup channel for enhancing the link availability by
simultaneously transmitting and receiving the primary channel and
the backup channel, once the bandwidth of the primary channel is
changed, the bandwidth of the backup channel is to be changed
regardless of a link state of the backup channel
[0098] On the contrary, in the case of the backup channel for
enhancing the link availability by switching in response to the
primary channel link loss, the bandwidth of the backup channel may
be changed separately regardless of the change of the bandwidth of
the primary channel
[0099] However, the entire bandwidth of the L band for CNPC that is
further likely to be used as the backup channel is less than that
of the C band that is further likely to be used as the primary
channel Accordingly, when fixing the bandwidth of the backup
channel to the bandwidth required to transmit only necessary
information, for example, TC and TM information as in Data Class 1
of Baseline Radio of Radio Technical Commission for Aeronautics
(RTCA) Minimum Operational Performance Standards (MOPS), in the
emergency case regardless of the bandwidth of the primary channel,
the bandwidth of the backup channel is not changed regardless of
change of the bandwidth of the primary channel
[0100] FIG. 2 illustrates an example of a procedure of assigning
and changing a channel in a P2P unmanned aircraft CNPC system
according to example embodiments.
[0101] Referring to FIG. 2, in operation S201, a spectrum authority
assigns a first CNPC frequency channel set to a GCS before takeoff
of an unmanned aircraft.
[0102] Here, the assigned frequency channel may be a distributed
frequency channel or a centralized frequency channel A description
related thereto will be made below.
[0103] In operation S202, the GCS transfers channel assignment
information to GRS1 for airspace volume 1. In operation S203, the
GCS receives a response that verifies assignment information from
the GRS1.
[0104] When the unmanned aircraft is required to enter airspace
volume 2 different from the airspace volume 1 due to the flight
plan of the unmanned aircraft after takeoff of the unmanned
aircraft in operation S204, the GCS receives assignment of a second
CNPC frequency channel set in operation S205.
[0105] In operation S206, the GCS monitors a link state of the
first CNPC frequency channel
[0106] On the contrary, when the unmanned aircraft is not required
to enter the airspace volume 2 different from the airspace volume 1
due to the flight plan of the unmanned aircraft after takeoff in
operation S204, the GCS may monitor the link state in operation
S206 without receiving the assignment of the second CNPC frequency
channel set.
[0107] In operation S206, the GCS may continuously monitor the link
state of the primary channel and the backup channel while operating
the unmanned aircraft CNPC system in the current airspace volume
through the first CNPC frequency channel set assigned before
takeoff. Link state monitoring may be performed by periodically
monitoring a BER/FER, SINR, and the like.
[0108] In operations S207 and S211, the GCS determines whether it
is difficult to use the first CNPC frequency channel set while
monitoring the link state.
[0109] Whether it is difficult to use a CNPC frequency channel set
may be determined based on whether the link state of the primary
channel or the backup channel satisfies a reference value.
[0110] When it is difficult to use the CNPC frequency channel set,
the GCS may return the channel to the spectrum authority and may
receive assignment of a new channel in operations S208 and
S212.
[0111] To prevent a CNPC link outage, returning and assigning the
primary channel and backup channel set may be sequentially
performed instead of being performed simultaneously.
[0112] That is, when it is difficult to use all of the primary
channel and backup channel set, the
[0113] GCS may initially return the primary channel to the spectrum
authority and receive assignment of a new frequency channel in
operation S208, may transfer information about the newly assigned
frequency channel to the GRS1 in operation S209, and may receive a
response that verifies change information from the GRS1 in
operation S210.
[0114] The GCS may return the backup channel to the spectrum
authority and receive assignment of a new backup frequency channel
in operation S212, may transfer information about the newly
assigned backup frequency channel to the GRS1 in operation S213,
and may receive a response that verifies change information from
the GRS1 in operation S214.
[0115] Here, sequence of changing the primary channel and the
backup channel is not limited thereto. When the backup channel is
initially changed, the primary channel may be changed.
[0116] Also, when it is difficult to use either the primary channel
or the backup channel, only a corresponding channel may be
changed.
[0117] When the unmanned aircraft enters an airspace volume
different from a current airspace volume due to the flight plan of
the unmanned aircraft, for example, when the unmanned aircraft is
to enter airspace volume 2 while flying in the airspace volume 1,
the GCS changes the first CNPC frequency channel set with the
second CNPC frequency channel set in operation S217.
[0118] The GCS may transfer assignment information of the second
CNPC frequency channel set to the GRS, for example, GRS2, for the
different airspace volume, for example, the airspace volume 2,
before the unmanned aircraft enters the new airspace volume, in
operation S215, and may receive a response that verifies the
assignment information in operation S216.
[0119] When the unmanned aircraft enters the other airspace volume,
the GCS operates the CNPC system using the second CNPC frequency
channel set in operation S217.
[0120] Operations S215 through S217 may be applicable to an
emergency situation, for example, a case in which the CNPC system
is to be operated using the second CNPC frequency channel as well
as a case in which the unmanned aircraft is to enter another
airspace volume.
[0121] The GCS may determine whether to return the assigned first
CNPC frequency channel set, which may be determined based on
whether the unmanned aircraft needs to reuse the first CNPC
frequency channel by reentering the airspace volume 1 after flying
the airspace volume 2.
[0122] When the unmanned aircraft reenters the airspace volume 1
immediately after flying in the airspace volume 2 due to the flight
plan of the unmanned aircraft in operation S218, the GCS does not
return the first CNPC frequency channel set.
[0123] However, when the unmanned aircraft enters airspace volume 3
instead of reentering the airspace volume 1 immediately after
flying the airspace volume 2 due to the flight plan in operation
S219, the GCS returns the first CNPC frequency channel set to the
spectrum authority and receives assignment of a third CNPC
frequency channel set in operation S220.
[0124] Although not illustrated in FIG. 2, GRS3 for airspace volume
3 may receive assignment information of the third CNPC frequency
channel set from the GCS and may set the CNPC system. Also, the GRS
may transmit a response that verifies channel assignment and change
information including setting complete information.
[0125] To return the first CNPC frequency channel set, the GCS
requests the spectrum authority for return of the first CNPC
frequency channel set in operation S221a, and transfers return
information of the first CNPC frequency channel set to the GRS1 in
operation S221b. The GCS receives a response that verifies return
of the first CNPC frequency channel set from the spectrum authority
in operation S222a, and receives a response that verifies return
information of the first CNPC frequency channel set from the GRS1
in operation S222b.
[0126] In operation S221b, the GCS is to notify the GRS1 having
used the corresponding channel of channel information assigned from
the spectrum authority and channel return information. In operation
222b, the GRS1 may close the CNPC system based on the channel
return information transferred from the GCS and may transfer the
response that verifies the return information.
[0127] The GCS may transfer channel information assigned from the
spectrum authority to the GRS3. Here, the GRS3 needs to verify
whether the channel information transferred from the GCS is channel
assignment information approved from the spectrum authority.
[0128] To this end, when the spectrum authority provides channel
assignment information to the GCS, the spectrum authority may
transmit the channel assignment information to the GRS, and the GRS
may verify whether the assigned channel is a valid channel by
comparing information provided from the spectrum authority and
information provided from the GCS.
[0129] However, in the above method, non-CNPC secured
wired/wireless link connection between the GRS and the spectrum
authority is to be forced.
[0130] As a method to outperform the above issue, when the spectrum
authority is to transmit channel assignment information to the GCS,
the channel assignment information may also be transmitted by
adding information, for example, a signature, indicating approval
of the spectrum authority to be recognizable only at the GRS and
unverifiable at the GCS.
[0131] When providing channel assignment information to the GRS,
the GCS may also provide information indicating that the channel
assignment is approved at the spectrum authority, and the GRS may
verify that the channel assignment information is valid information
by verifying the information.
[0132] When the flight of the unmanned aircraft is terminated in
the airspace volume 2 without reentering the airspace volume 1
immediately after flying in the airspace volume 2 due to the flight
plan of the unmanned aircraft, the GCS may not return the first
CNPC frequency channel set.
[0133] Also, when the unmanned aircraft is scheduled to enter the
airspace volume 3 before reentering the airspace volume 1
regardless of a schedule of reentering the airspace volume 1, the
GCS may return the first CNPC frequency channel set and may receive
assignment of a third CNPC frequency channel set to enter the
airspace volume 3.
[0134] A CPNC frequency assignment and return may be performed
because maximum two CNPC frequency channel sets are assignable to a
single unmanned aircraft.
[0135] In addition to the above situation, the P2P unmanned
aircraft CNPC system may need to change the GRS in the same
airspace volume or may need to change the airspace volume in the
same GRS.
[0136] When the GRS is to be changed in the same airspace volume,
an existing CNPC channel set may be used and the GCS may change
only the GRS without changing a channel.
[0137] However, if the GRS is changed, CNPC characteristic
information of a changed GRS may differ from that of a basic GRS
due to a location change. Thus, an interference situation may vary
and the existing channel set may not be used.
[0138] In this case, the GCS needs to change a change by requesting
the spectrum authority for a new channel set. Although the GCS does
not change the existing CNPC channel set since change by
interference effect is absent, the GCS needs to provide changed GRS
information to the spectrum authority by requesting the changed GRS
information and the existing CNPC channel set.
[0139] If the airspace volume is changed at the same GRS, the GCS
may request the spectrum authority for a CNPC channel set and may
provide GRS information, and the GRS may receive assignment of a
new channel from the spectrum authority, as in an additional
channel assignment procedure for entering another airspace
volume.
[0140] If a GCS for controlling the unmanned aircraft is
transferred, the spectrum authority needs to be notified of related
information so that the spectrum authority may monitor a GCS using
a corresponding CNPC channel
[0141] In the P2P unmanned aircraft CNPC system, the GCS receives
assignment of an uplink/downlink frequency channel (center
frequency and channel bandwidth) from the spectrum authority.
[0142] In an uplink TDMA/downlink FDMA P2MP unmanned aircraft CNPC
system, the GRS receives assignment of an uplink frequency channel
(center frequency and channel bandwidth) from the spectrum
authority, and the GCS receives assignment of a downlink frequency
channel (center frequency and channel bandwidth) from the spectrum
authority and an uplink time slot in the uplink frequency channel
assigned to the GRS.
[0143] Accordingly, in the P2MP unmanned aircraft CNPC system, the
GRS registers CNPC transmission/reception device information
(transceiver location, waveform, GRS location, antenna pattern,
transmission power, receiver sensitivity, etc.) of the GRS to the
spectrum authority and, at the same time, receives assignment of
the uplink frequency channel (center frequency and channel
bandwidth) from the spectrum authority.
[0144] The GCS receives information about a GRS to be used due to
the flight plan from the spectrum authority, receives assignment of
an uplink time slot in a frequency channel assigned to the GRS from
the spectrum authority, and receives assignment of a downlink
frequency channel from the spectrum channel
[0145] The GCS receives assignment of a CNPC channel from the
spectrum authority based on a unit of a CNPC channel set (primary
or primary/backup uplink time slot/downlink frequency channel).
That is, the GCS requests the spectrum authority for assigning a
single primary channel or a primary channel and a single backup
channel as a CNPC channel for operating the unmanned aircraft based
on the flight plan, the unmanned aircraft/GRS capability, a current
CNPC channel use state, and the like.
[0146] As described above, a single unmanned aircraft CNPC system
may maintain the maximum two CNPC channel sets. Thus, to secure
another channel set in a state in which the two CNPC channel sets
are secured, the unmanned aircraft CNPC system may return one of
the existing channel sets and may request assignment of another
channel
[0147] The backup channel (uplink time slot and downlink frequency
channel) may be simultaneously assigned together with the primary
channel (uplink time slot and downlink frequency channel), or may
be assigned independently.
[0148] That is, only the backup frequency channel between the
primary channel and the backup frequency channel may be
changed.
[0149] Hereinafter, a channel assignment procedure of the P2MP
unmanned aircraft CNPC system will be described with reference to
FIGS. 3A through 3C.
[0150] FIGS. 3A through 3C illustrate examples of a new channel
assignment procedure after general assignment and channel return in
a P2MP unmanned aircraft CNPC system according to example
embodiments.
[0151] FIG. 3A illustrates an example of assigning a single
frequency channel set to the P2MP unmanned aircraft CNPC system
according to example embodiments.
[0152] In operation S311, a GRS provides CNPC
transmission/reception device information (transceiver location,
waveform, GRS location, antenna pattern, transmission power,
receiver sensitivity, etc.) of the GRS to a spectrum authority and,
at the same time, requests the spectrum authority for assigning an
uplink channel
[0153] In operation S312, the GRS receives assignment of an uplink
frequency channel (center frequency and channel bandwidth) from the
spectrum authority.
[0154] In operation S313, in response to the channel assignment,
the GRS transmits a response that verifies the channel assignment
to the spectrum authority.
[0155] In operation S314, the GCS requests the spectrum authority
for assigning a single CNPC channel set available in the first
airspace volume present in a flight path of the unmanned
aircraft.
[0156] In operation S315, in response to the request, the spectrum
authority assigns a frequency channel to the GCS based on a CNPC
channel set unit.
[0157] Here, the frequency channel to be assigned may include a
time slot in a GRS uplink frequency, and a downlink center
frequency and channel bandwidth. The channel set may include a
primary or primary/backup uplink time slot/downlink frequency
channel.
[0158] That is, in operation S314, the GCS may request the spectrum
authority for assigning a single primary channel or a single
primary channel and a single backup channel as a CNPC channel for
operating the unmanned aircraft based on the flight plan, the
unmanned aircraft/GRS capability, a current CNPC channel use state,
etc.
[0159] In operation S316, the GCS may transmit a response that
verifies the channel assignment to the spectrum authority.
[0160] FIG. 3B illustrates an example of assigning an additional
frequency set to the P2MP unmanned aircraft CNPC system after
assigning a frequency set according to example embodiments.
[0161] Operations S321 through S326 of FIG. 3B are the same as
operations S311 through S316 of FIG. 3A.
[0162] Here, in operations S321 through S323, in the P2MP unmanned
aircraft CNPC system, the GRS receives assignment of the uplink
frequency channel (center frequency and channel bandwidth). Thus,
an additional GRS2 also provides GRS CNPC transmission/reception
information and receives assignment of an uplink channel and
provides a response that verifies the channel assignment.
[0163] A CNPC channel set includes information about an airspace
volume in which a corresponding channel is available. When a flight
plan to another airspace volume in which the assigned CNPC channel
set is unavailable is included in a flight path of the unmanned
aircraft, the flight to the other airspace volume needs to be
prepared.
[0164] In operation S327, after takeoff, the GCS requests the
spectrum authority for assigning another CNPC channel set for the
flight to the other airspace volume.
[0165] In operation S328, in response to the request, the spectrum
frequency assigns a frequency channel based on a CNPC channel set
unit.
[0166] In operation S329, in response to the channel assignment,
the GCS transmits a response that verifies the channel assignment
to the spectrum authority.
[0167] FIG. 3C illustrates an example in which the P2MP unmanned
aircraft CNPC system returns the assigned frequency set and
receives assignment of a new frequency set according to example
embodiments.
[0168] If three or more airspace volumes each in which a different
CNPC channel set is available are present in the flight path of the
unmanned aircraft, the GCS requires three CNPC channel sets in the
flight path.
[0169] The GCS may continuously request the spectrum authority for
assigning a CNPC channel set. However, since a CNPC spectrum is
limited, a single unmanned aircraft CNPC system may be limited to
maintain maximum two CNPC channel sets.
[0170] Accordingly, to secure another channel set in a state in
which the two CNPC channel sets are secured, the GCS needs to
return one of the existing channel sets to the spectrum authority
and then request assignment of another channel.
[0171] For example, when the unmanned aircraft is flying in the
second airspace volume, the GCS may return an existing single
channel used in the first airspace volume and may request the
spectrum authority for assigning a CNPC channel available in the
third airspace volume.
[0172] Referring to FIG. 3C, in operation S331, the GCS notifies
the spectrum authority of a channel return schedule, and requests
the spectrum authority for assigning a new channel
[0173] That is, the GCS notifies the spectrum authority that the
GCS is to return the existing single channel used in the first
airspace volume, and requests the spectrum authority for assigning
a CNPC channel available in the third airspace volume.
[0174] In operation S332, the spectrum authority notifies the GCS
that the new channel is assignable.
[0175] In operation S333, the GCS returns the maintained channel to
the spectrum authority.
[0176] In operation S334, the spectrum authority verifies the
channel return and assigns the new channel to the GCS.
[0177] In operation S335, the GCS receives assignment of the new
channel and transmits, to the spectrum authority, a response that
verifies the channel assignment.
[0178] Also, in operations S331 through S335, when changing the
primary channel, the channel bandwidth as well as the center
frequency may also be changed. In the case of uplink, the channel
bandwidth/number of time slots as well as the center frequency may
be changed.
[0179] However, during the flight of the unmanned aircraft, change
of the channel frequency and the bandwidth is not recommended based
on a service rate required at the unmanned aircraft in real time.
Thus, only in the case of requesting assignment of another primary
channel so that the unmanned aircraft may move to the airspace
volume in which the primary frequency channel currently in use is
unavailable, change of the downlink frequency band and uplink time
slot may also be requested.
[0180] In general, when requesting an uplink time slot and a
downlink channel bandwidth for the primary channel before takeoff,
the assignment may be performed based on a CNPC service to be used
during the entire flight of the unmanned aircraft. Thus, when
changing the primary channel, change of the uplink time slot and
the downlink channel bandwidth may not be considered generally.
[0181] However, when entering another airspace volume, a bandwidth
that is assigned from the spectrum authority to a GRS used for the
unmanned aircraft CNPC system in the airspace volume may differ
from a bandwidth that is assigned to the existing GRS. In this
case, the uplink center frequency and the channel bandwidth need to
be changed.
[0182] Also, according to an increase in a number of time slots and
the bandwidth requested to be assigned, an amount of time used to
receive channel assignment from the spectrum assignment is highly
likely to increase. Accordingly, a relatively small downlink
bandwidth and uplink time slot may be requested to be assigned
based on only a required service. In this case, the channel change
may be performed together with change of the center frequency of
the uplink/downlink channel based on change in the downlink channel
bandwidth and a number of uplink time slots.
[0183] Two CNPC channel sets that a single unmanned aircraft CNPC
system may simultaneously maintain are for different airspace
volumes that do not allow the same CNPC channel based on a
frequency reuse policy.
[0184] Due to a limited CNPC spectrum, a single unmanned aircraft
CNPC system does not simultaneously maintain two CNPC channel sets
each available in a single airspace volume. Accordingly, change of
the primary channel and the backup channel in a specific airspace
volume may proceed through a procedure of returning an existing
channel and receiving assignment of a new channel. In this case,
the primary channel and the backup channel may not be
simultaneously changed in order to prevent CNPC link outage between
return of the existing channel and use of the new channel
[0185] Meanwhile, frequency change of the primary channel or the
backup channel in the specific airspace volume is performed
generally when a CNPC backup link is in a poor state. When the link
state is poor during monitoring the link state of the primary
channel or the backup channel, for example, monitoring a BER, an
SINR, a link loss alert, and the like, it is possible to request
the spectrum authority for another primary or backup frequency
channel.
[0186] As described above, a relatively small bandwidth and a small
number of time slots may be requested to be assigned when changing
the primary channel On the contrary, a downlink frequency bandwidth
and a number of uplink time slots of the backup frequency channel
may be differently changed based on whether a backup channel is a
backup channel for enhancing the link availability by
simultaneously transmitting and receiving the primary channel and
the backup channel, and a backup channel for enhancing the link
availability by switching to the backup channel in response to
primary channel link loss.
[0187] To simultaneously transmit and receive the primary channel
and the backup channel, the number of uplink time slots and the
downlink bandwidth of the primary channel are to be same as those
of the backup channel. Accordingly, in the case of the backup
channel for enhancing the link availability by simultaneously
transmitting and receiving the primary channel and the backup
channel, once the number of uplink time slots and the downlink
bandwidth of the primary channel are changed, the number of uplink
time slots and the downlink bandwidth of the backup channel are to
be changed regardless of a link state of the backup channel On the
contrary, in the case of the backup channel for enhancing the link
availability by switching in response to the primary channel link
loss, the bandwidth of the backup channel may be changed separately
regardless of the change of the bandwidth of the primary
channel
[0188] However, the entire bandwidth of the L band for CNPC that is
further likely to be used as the backup channel is less than that
of the C band that is further likely to be used as the primary
channel Accordingly, when fixing the bandwidth of the backup
channel to the bandwidth required to transmit only necessary
information, for example, TC and TM information as in data class 1
of baseline radio of RTCA MOPS, in the emergency case regardless of
the bandwidth of the primary channel, the bandwidth of the backup
channel is not changed regardless of change of the bandwidth of the
primary channel
[0189] As described above, in the P2MP type, a single GRS
simultaneously supports a plurality of unmanned aircrafts. A
connection scheme between the single GRS and the plurality of
unmanned aircrafts uses a TDMA scheme in the case of uplink and
uses an FDMA scheme in the case of downlink.
[0190] Accordingly, in the case of uplink, the unmanned aircrafts
supported at the single GRS use the same frequency channel and may
be identified based on a time slot. Accordingly, the spectrum
authority assigns an uplink frequency channel and an uplink time
slot to each GCS. The spectrum authority needs to be aware of a GRS
to be used at the GCS and time slot assignment information
associated with the GRS.
[0191] In the case of a GRS, a further large number of time slots
may be required according to an increase in a number of unmanned
aircrafts supported at the GRS. In this case, a CNPC channel
frequency bandwidth is to be increased. However, it may not be easy
for the GRS to dynamically change the channel frequency bandwidth
since the GRS supports a plurality of unmanned aircrafts.
[0192] If the GRS dynamically changes the channel frequency
bandwidth, the GRS needs to notify an unmanned aircraft having
formed a CNPC communication link with the GRS of the change and the
GRS needs to dynamically change a receiver according to the change
of the frequency bandwidth of the GRS.
[0193] Accordingly, an uplink frequency may be semi-statically
assigned to the GRS in order to further efficiently manage a
channel and to reduce P2MP communication complexity.
[0194] Also, in the case of dynamically changing the uplink
frequency channel of the GRS, the GCS using the corresponding GRS
needs to transfer channel information to the GRS every time the GCS
requests the spectrum authority for a channel. Thus, a network
connection between the GRS and the spectrum authority is required.
Accordingly, an uplink frequency may be semi-statically assigned to
the GRS in order to further efficiently manage a channel and to
reduce P2MP communication complexity.
[0195] Since an uplink frequency is statically assigned to the GRS
during a predetermined amount of time, a method in which a GRS
operator assigns in advance an uplink frequency channel based on
the GRS capability while registering the GRS and the spectrum
authority assigns an uplink time slot and a downlink channel in
response to a channel request from the GCS may be employed.
[0196] Here, the spectrum authority may immediately transfer, to
the GRS, information about a channel assigned to the GCS. Instead
of transferring the information to the GRS, the GCS may receive
corresponding GRS information from the spectrum authority and may
notify the GRS of the corresponding information in response to
attempt CNPC communication through the GRS. However, as described
above, when transferring channel assignment information to the GRS,
an additional network between the spectrum authority and the GRS is
required. Thus, channel information may be transferred from the GCS
to the GRS, which is similar to the P2P type.
[0197] The uplink frequency bandwidth of the P2MP type may be
relatively great compared to that of the P2P type. Thus, when a P2P
CNPC channel assignment request and a P2MP CNPC channel assignment
request coexist, channel assignment for the P2MP type having a
relatively wideband may be difficult. Accordingly, when performing
frequency assignment with respect to the P2P CNPC and the P2MP
CNPC, the spectrum authority may need to separate a frequency to be
assigned for the P2P type and a frequency to be assigned for the
P2MP type based on the above aspect.
[0198] FIG. 4 illustrates an example of a procedure of assigning
and changing a channel in a P2MP unmanned aircraft CNPC system
according to example embodiments.
[0199] The channel assignment and change procedure of the P2MP type
may be similar to that of the P2P type, however, may differ in that
an uplink frequency is assigned to a GRS before a request for
channel assignment from a GCS, P2MP GRS information is registered
in advance to a spectrum authority, a GRS to be used at the GCS is
approved from the spectrum authority, the spectrum authority
assigns a time slot and a downlink frequency available in the GRS
to the GCS, frequencies of a primary channel and a backup channel
in the same airspace volume are changed only in downlink, and only
a time slot is changed in uplink.
[0200] Operations S403 through S424b of FIG. 4 may be matched to
operations S201 through S222b of FIG. 2, and the channel assignment
and change procedure of the P2MP type may further include
operations S401 and S402. Also, a configuration of a frequency
channel set assigned from the spectrum authority to the GCS
differs, which will be described with reference to FIG. 4.
[0201] In operation S401, a GRS1 registers information of the GRS1
to the spectrum authority and receives assignment of an uplink
frequency.
[0202] Operation S401 corresponds to operations S311 through S313
of FIG. 3A. The GRS provides CNPC transmission/reception device
information (transceiver location, waveform, GRS location, antenna
pattern, transmission power, receiver sensitivity, etc.) of the GRS
to the spectrum authority and, at the same time, requests the
spectrum assignment for assigning an uplink channel. The GRS
receives assignment of an uplink frequency channel (center
frequency and channel bandwidth) from the spectrum authority. The
GRS transmits a response that verifies the channel assignment to
the spectrum authority.
[0203] In operation S402, a GRS2 registers information of the GRS2
to the spectrum authority and receives assignment of an uplink
frequency.
[0204] Based on the information, the GCS or the spectrum authority
may select available candidate GRSs, may select an appropriate GRS
from among the candidate GRSs through an interference analysis, and
may select an uplink time slot and a downlink frequency available
in the GRS according to distributed and centralized channel
assignment methods.
[0205] Hereinafter, the distributed and centralized channel
assignment method in which the spectrum authority efficiently
assigns and manages a limited spectrum for controlling an unmanned
aircraft in the national airspace to support the proposed channel
assignment method and procedure will be described.
[0206] The proposed unmanned aircraft CNPC dynamic channel
assignment method may be divided into a distributed channel
assignment method and a centralized channel assignment method based
on an entity that analyzes a CNPC channel available within the
unmanned aircraft CNPC operation range of the national airspace
into consideration of the unmanned aircraft flight plan and CNPC
operation environment at each GCS, and the like.
[0207] The distributed and centralized channel assignment methods
of the P2P type will be described with reference to FIGS. 5A and
5B.
[0208] FIG. 5A illustrates an example of a distributed channel
assignment procedure in a P2P type according to example
embodiments.
[0209] FIG. 5B illustrates an example of a centralized channel
assignment procedure in a P2P type according to example
embodiments.
[0210] In the distributed channel assignment method of the P2P
type, a GCS analyzes an available channel by considering the flight
plan and the CNPC operation environment, etc., based on information
provided from a spectrum authority and requests the spectrum
authority for a single channel from the analyzed available channel
set, and the spectrum authority verifies whether the channels
requested from the respective GCSs are safely available in the
aerospace volume and determines whether to approve the requested
channels.
[0211] In the distributed channel assignment method, the GCS is
required to select a safe frequency channel to be used during an
operation of the unmanned aircraft using an optimal channel
selection algorithm tool.
[0212] That is, the GCS functions to find an available channel and
the spectrum authority functions to verify whether a frequency
channel selected at the GCS may be safely available in a CNPC
operation area within the aerospace volume through an interference
analysis algorithm.
[0213] This method may reduce burden of the spectrum authority
since the spectrum authority provides only a web-based tool through
which the GCS may input flight plan information and selection
frequency information through the Internet.
[0214] Referring to FIG. 5A, in operation S511, the GCS connects to
a server of the spectrum authority.
[0215] In operation S512, the spectrum authority provides the
interference analysis algorithm to the GCS to determine an
assignment database and channel assignment in operation S512. In
operation S513, the GCS retrieves an available channel
[0216] The assignment database may include information about a
currently assigned unmanned aircraft CNPC channel, for example,
information (signal bandwidth, maximum transmission power, receiver
sensitivity, etc.) about waveforms of currently assigned CNPC
channels, three-dimensional (3D) locations of the GRS and the
unmanned aircraft (including GRS and unmanned aircraft mobility
information according to the flight plan), an antenna pattern, etc.
Also, the spectrum authority provides, to the GCS, the analysis
algorithm used to accept and refuse channel assignment.
[0217] Here, the interference analysis algorithm may consider a
worst situation that may be considered as interference based on
database information about all CNPC interference channels in a
current CNPC channel assignment situation due to the flight plan of
the unmanned aircraft.
[0218] The GCS may develop and use a further efficient and optimal
channel selection algorithm based on the interference analysis
algorithm provided from the spectrum authority.
[0219] Accordingly, the GCS may use an algorithm tool for analyzing
interference and selecting an optimal CNPC channel based on the
interference analysis algorithm provided from the spectrum
authority, and the spectrum authority may use an algorithm tool for
analyzing interference to determine whether the channel selected at
the GCS is available without interference in the current CNPC
channel assignment situation.
[0220] A priority between GCSs to use a CNPC channel is determined
based on a first-come, first-served (FCFS) basis.
[0221] In operation S514, the GCS requests the spectrum authority
for assigning a channel and provides the flight plane/CNPC
characteristic information to the spectrum authority.
[0222] When the GCS requests the spectrum authority for a CNPC
channel in operation S514, the GCS may provide information
(bandwidth, maximum transmission power, receiver sensitivity, etc.)
about a CNPC waveform used in association with radio frequency (RF)
compatibility, and transceiver antenna patterns and locations of
the unmanned aircraft and all of the GRSs to the spectrum
authority.
[0223] Here, an antenna location is 3D information that includes a
minimum altitude and a maximum altitude. In the case of the
unmanned aircraft, 3D information including the flight plan and the
altitude according to the flight plan of the unmanned aircraft may
be provided. In the case of the GRS, 3D information including the
altitude associated with an installation location of the GRS may be
provided.
[0224] If the GRS is a mobile GRS, the GCS may provide movement
information of the GRS. The antenna pattern may be provided using
3D antenna beam pattern information that includes minimum/maximum
antenna gain information between the GRS and the unmanned aircraft.
If a steering antenna is used, steering antenna information, for
example, steering beam accuracy, beam antenna gain, etc., of the
unmanned aircraft or the GRS during a period of using the CNPC
channel may be provided.
[0225] The spectrum authority verifies the availability through
interference analysis based on the requested channel information
and the flight plan and CPNC characteristic information in
operation S515, and assigns a channel to the GCS in operation
S516.
[0226] In operation S517, in response to the channel assignment,
the GCS transmits a response that verifies the channel assignment
to the spectrum authority.
[0227] For the stable operation of the unmanned aircraft in the
national aerospace, the GCS reports to the spectrum authority about
the CNPC link outrage that causes a situation in which the unmanned
aircraft is uncontrollable during at least a predetermined period
of time, generally, a few seconds or less, every time the CNPC link
outrage occurs.
[0228] Also, to update and enhance an interference analysis
algorithm for selecting an optimal channel for the GRS by applying
an assignment algorithm to an interference situation according to a
current CNPC channel assignment situation in real time, the GCS may
provide CNPC link state information of the GCS to the spectrum
authority.
[0229] The CNPC link state information may include, for example, a
BER/FER, a SINR, etc. If each numerical value is less than or equal
to a reference BER/FER or SINR, the GCS may regard that the CNPC
link outrage has occurred and may report to the spectrum authority
about the CNPC link outrage.
[0230] If the channel assignment is impossible, the spectrum
authority notifies the GRS that the channel assignment is
disallowed in operation S518. The GCS reconnects to the server of
the spectrum authority in operation S519, and verifies whether the
assignment database and the interference analysis algorithm are
updated and receives related information in operation S520.
[0231] In operation S521, the GCS reselects an available channel
through interference analysis. In operation S522, the GCS requests
again the spectrum authority for assigning a channel and, if the
flight plan and the CNPC characteristic information are updated,
provides the updated flight plan and CNPC characteristic
information to the spectrum authority.
[0232] In operation S523, the spectrum authority verifies whether
the channel is available through interference analysis based on the
requested channel information and the updated flight plan and CNPC
characteristic information. In operation S524, the spectrum
authority assigns a channel to the GCS.
[0233] In operation S525, in response to the channel assignment,
the GCS transmits a response that verifies the channel assignment
to the spectrum authority.
[0234] Hereinafter, the centralized channel assignment method of
the P2P type will be described with reference to FIG. 5B. In the
centralized channel assignment method of the P2P type, the spectrum
authority analyzes and assigns a channel suitable for each GCS
having requested the channel assignment, based on the flight plan
and CNPC operation environment information (CNPC waveform
information, such as bandwidth, maximum transmission power,
receiver sensitivity, etc., locations and antenna patterns of the
GRS/unmanned aircraft, etc.) provided from each GCS.
[0235] That is, in the distributed channel assignment method, the
GCS performs the interference analysis and channel selection
process. In the centralized channel assignment method, the spectrum
authority performs the interference analysis and channel selection
process.
[0236] In the centralized channel assignment method of the P2P
type, a priority between GCSs to use a CNPC channel needs to be
defined through an appropriate method in order to optimally utilize
insufficient CNPC resources.
[0237] In the distributed channel assignment method, the priority
may be determined based on a FCFS basis. However, in this case, it
may be difficult to efficiently use CNPC resources. The centralized
channel assignment method needs to consider a further efficient
assignment priority in order to optimally use a limited CNPC
frequency.
[0238] Referring to FIG. 5B, the GCS connects to the server of the
spectrum authority in operation S551, and provides the flight plan
and CNPC characteristic information to the spectrum authority and
requests the spectrum authority for a CNPC channel in operation
S552. The spectrum authority selects one of CPNC channels suitable
for the GCS through interference analysis in operation S553 and
assigns the selected CNPC channel to the GCS in operation S554. The
GCS transmits a response that verifies the channel assignment in
operation S555.
[0239] If the channel assignment is impossible, the spectrum
authority notifies the GCS that the channel assignment is
disallowed and in this instance, may also notify the GCS of a
reason thereof in the case of the centralized channel assignment
method in operation S556, which differs from the distributed
channel assignment method.
[0240] If the spectrum authority notifies the GCS of the reason why
channel assignment is difficult, such as saturation of the CNPC
channel, a degraded interference situation, an increase in a number
of GCSs that have requested the channel assignment at the same
time, and the like, the GCS may update the flight plan and CNPC
characteristic information, etc., to be advantageous for the
channel assignment based on the notified information.
[0241] In operation S557, the GCS reconnects to the server of the
spectrum authority. In operation S558, the GCS requests again the
spectrum authority for assigning a channel and provides the updated
flight plan and CNPC characteristic information.
[0242] In operation S559, the spectrum authority selects an
available channel through interference analysis based on the
requested channel information and the updated flight plan and CNPC
characteristic information. In operation S560, the spectrum
authority assigns the channel to the GCS.
[0243] In operation S561, in response to the channel assignment,
the GCS transmits a response that verifies the channel assignment
to the spectrum authority.
[0244] Hereinafter, distributed and centralized channel assignment
methods of a P2MP type will be described with reference to FIGS. 6A
and 6B.
[0245] FIG. 6A illustrates an example of a distributed channel
assignment procedure in a P2MP type according to example
embodiments.
[0246] FIG. 6B illustrates an example of a centralized channel
assignment procedure in a P2MP type according to example
embodiments.
[0247] In the P2MP type, a plurality of GRSs are present and thus,
a P2MP GRS registers in advance information about the corresponding
GRS to a spectrum authority and receives assignment of an uplink
frequency to be used at the GRS from the spectrum authority.
[0248] In operation S611, the GRS connects to a server of the
spectrum authority. In operation S612, the spectrum authority
provides, to the GRS, an interference analysis algorithm for
determining an assignment database and whether to assign a channel
In operation S613, the GRS retrieves an available channel
[0249] Here, the assignment database may include information about
a currently assigned unmanned aircraft CNPC channel, for example,
information (signal bandwidth, maximum transmission power, receiver
sensitivity, etc.) about waveforms of currently assigned CNPC
channels, 3D locations of the GRS and the unmanned aircraft
(including GRS and unmanned aircraft mobility information according
to the flight plan), an antenna pattern, etc. Also, the spectrum
authority provides, to the GCS, the analysis algorithm used to
accept and refuse channel assignment.
[0250] Here, the interference analysis algorithm may consider a
worst situation that may be considered as interference based on
database information about all CNPC interference channels in a
current CNPC channel assignment situation due to the flight plan of
the unmanned aircraft flight plan.
[0251] The GRS may develop and use a further efficient and optimal
channel selection algorithm based on the interference analysis
algorithm provided from the spectrum authority.
[0252] Accordingly, the GRS may use an algorithm tool for analyzing
interference and selecting an optimal CNPC channel based on the
interference analysis algorithm provided from the spectrum
authority, and the spectrum authority may use an algorithm tool for
analyzing interference to determine whether the channel selected at
the GRS is available without interference in the current CNPC
channel assignment situation.
[0253] A priority between GRSs to use a CNPC channel is determined
based on an FCFS basis.
[0254] When the GRS requests the spectrum authority for a CNPC
channel in operation S614, the GRS may provide information
(bandwidth, maximum transmission power, receiver sensitivity, etc.)
about a CNPC waveform used in association with RF compatibility,
and transceiver antenna patterns and locations of the unmanned
aircraft and all of the GRSs to the spectrum authority.
[0255] Here, an antenna location is 3D information that includes a
minimum altitude and a maximum altitude. In the case of the
unmanned aircraft, 3D information including the flight plan and the
altitude according to the flight plan of the unmanned aircraft may
be provided. In the case of the GRS, 3D information including the
altitude associated with an installation location of the GRS may be
provided.
[0256] If the GRS is a mobile GRS, the GRS may provide movement
information of the GRS. The antenna pattern may be provided using
3D antenna beam pattern information that includes minimum/maximum
antenna gain information between the GRS and the unmanned aircraft.
If a steering antenna is used, steering antenna information, for
example, steering beam accuracy, beam antenna gain, etc., of the
unmanned aircraft or the GRS during a period of using the CNPC
channel may be provided.
[0257] In operation S615, the spectrum authority verifies whether
the channel is available through interference analysis based on the
requested channel information and the flight plan and CNPC
characteristic information. In operation S616, the spectrum
authority assigns a channel to the GCS.
[0258] In operation S617, in response to the channel assignment,
the GCS transmits a response that verifies the channel assignment
to the spectrum authority.
[0259] In operation S618, the GCS connects to the server of the
spectrum authority. In the case of uplink, the GCS acquires
information about available candidate GRSs together with an
existing CNPC channel database provided from the spectrum authority
in operation 619, which is similar to the P2P type, and selects an
available GRS and a time slot assignable from the GRS through
interference analysis in operation S620. In the case of downlink,
the GCS receives assignment of a channel in the same manner as in
the P2P type.
[0260] In operation S621, the GCS requests the spectrum authority
for assigning the selected channel, notifies the GRS to be used of
the channel assignment, and provides the flight plan and CNPC
characteristic information.
[0261] When requesting the spectrum authority for assigning a
channel, the GCS needs to request the spectrum authority to approve
a P2MP GRS to be used. When providing CNPC characteristic
information, the GCS has no need to provide GRS related
information.
[0262] In operation S622, the spectrum authority verifies whether
the channel is available through interference analysis based on the
requested channel information and the flight plan and CNPC
characteristic information. In operation S623, the spectrum
authority assigns the channel to the GCS.
[0263] In operation S624, in response to the channel assignment,
the GCS transmits a response that verifies the channel assignment
to the spectrum authority.
[0264] If the channel assignment is impossible, the spectrum
authority notifies the GCS that the channel assignment is
disallowed in operation S625. In operation S626, the GCS reconnects
to the server of the spectrum authority. In operation S627, the GCS
receives an assignment database, GRS information, and the
interference analysis algorithm.
[0265] In operation S628, the GCS reselects an available channel
through interference analysis based on the received information. In
operation S629, the GCS requests again the spectrum authority for
assigning a channel and, if the flight plan and the CNPC
characteristic information are updated, provides the updated flight
plan and CNPC characteristic information to the spectrum
authority.
[0266] In operation S630, the spectrum authority verifies whether
the channel is available through interference analysis based on the
requested channel information and the updated flight plan and CNPC
characteristic information. In operation S631, the spectrum
authority assigns a channel to the GCS and approves the GRS.
[0267] In operation S632, in response to the channel assignment,
the GCS transmits a response that verifies the channel assignment
to the spectrum authority.
[0268] Dissimilar to the channel assignment method of the P2P type,
the channel assignment method of the P2MP type further includes a
process in which the spectrum authority assigns an uplink frequency
channel to the GRS. That is, a channel to be assigned to the GRS is
an uplink frequency channel, a channel to be assigned to the GCS is
a downlink frequency channel and a time slot in an uplink frequency
assigned to the GRS in use is assigned.
[0269] Here, if the GRS receives a notification indicating that the
channel assignment is disallowed from the spectrum authority, the
same procedure as a case in which the GCS receives the notification
from the spectrum authority may proceed.
[0270] Dissimilar to the channel assignment method of the P2P type,
the P2MP GRS needs to be registered in advance before the channel
is assigned to the GCS. Every time registration information is
changed, the GRS notifies the spectrum authority of the change and
the spectrum authority updates GRS information.
[0271] Hereinafter, the centralized channel assignment method of
the P2MP type will be described with reference to FIG. 6B.
[0272] In operation S651, the GRS connects to the server of the
spectrum authority. In operation S652, the GRS requests the
spectrum authority for assigning an uplink frequency channel and
provides GRS information.
[0273] Registration information may include CNPC waveform
information (signal bandwidth, a number of slots, maximum
transmission power, receiver sensitivity, etc.) associated with the
GRS, GRS antenna pattern information, and GRS transceiver location
information. Also, the registration information may include
information regarding a mobile GRS and a steering antenna pattern,
if necessary.
[0274] The spectrum authority selects an uplink frequency available
in the GRS through interference analysis in operation S653, and
assigns the selected uplink frequency to the GRS in operation S654.
In operation S655, the GRS transmits a response that verifies the
channel assignment.
[0275] In operation S656, the GCS connects to the server of the
spectrum authority. In operation S657, the GCS requests the
spectrum authority for assigning a channel and notifies the
spectrum authority of a GRS to be used, and provides the flight
plan and CNPC characteristic information.
[0276] In operation S658, the spectrum authority verifies whether
the channel is available through interference analysis based on the
requested channel information and the flight plan and CNPC
characteristic information. In operation S659, the spectrum
authority assigns the channel to the GCS.
[0277] Similar to the P2P type, in the case of uplink, it is
possible to perform interference analysis by acquiring an existing
assigned CNPC channel database, information about available
candidate GRSs, etc. In this manner, it is possible to request the
GRS to be used at the GCS and a time slot assignable from the
GRS.
[0278] In the case of downlink, a channel is assigned in the same
manner as in the P2P type. The GCS needs to notify the spectrum
authority of a GRS to be used when requesting the spectrum
authority for a selected channel Dissimilar to the P2P type, GRS
related information in CNPC characteristic information to be used
at the GCS is already registered to the spectrum authority. Thus,
there is no need to provide the GRS related information. The
spectrum authority assigns an uplink time slot and a downlink
frequency channel and approves the GRS to be used.
[0279] In operation S660, the GCS transmits a response that
verifies the channel assignment to the spectrum authority.
[0280] If the channel assignment is impossible, the spectrum
authority notifies the GCS that the channel assignment is
disallowed and in this instance, may also notify the GCS of a
reason thereof in the case of the centralized channel assignment
method in operation S661, which differs from the distributed
channel assignment method.
[0281] If the spectrum authority notifies the GCS of the reason why
channel assignment is difficult, such as saturation of the CNPC
channel, a degraded interference situation, an increase in a number
of GCSs that have requested the channel assignment at the same
time, and the like, the GCS may update the flight plan and CNPC
characteristic information, etc., to be advantageous for the
channel assignment based on the notified information.
[0282] In operation S662, the GCS reconnects to the server of the
spectrum authority. In operation S663, the GCS requests again the
spectrum authority for assigning a channel and provides the updated
flight plan and CNPC characteristic information.
[0283] In operation S664, the spectrum authority selects an
available channel through interference analysis based on the
requested channel information and the updated flight plan and CNPC
characteristic information. In operation S665, the spectrum
authority assigns the channel to the GCS.
[0284] In operation S666, in response to the channel assignment,
the GCS transmits a response that verifies the channel assignment
to the spectrum authority.
[0285] Dissimilar to the channel assignment method of the P2P type,
the channel assignment method of the P2MP type further includes a
process in which the spectrum authority assigns an uplink frequency
channel to the GRS. That is, a channel to be assigned to the GRS is
an uplink frequency channel, a channel to be assigned to the GCS is
a downlink frequency channel and a time slot in an uplink frequency
assigned to the GRS in use is assigned.
[0286] Also, the P2MP GRS needs to be registered to the spectrum
authority before the channel is assigned to the GCS. Every time
registration information is changed, the GRS notifies the spectrum
authority of the change and the spectrum authority needs to update
GRS information.
[0287] When assigning a channel to the GCS, the spectrum authority
also needs to designate the P2MP GRS to be used and the GCS has no
need to provide GRS related information when providing CNPC
characteristic information. In the P2MP type of FIGS. 6A and 6B,
channel assignment and change may be performed at the GRS based on
a centralized type and at the GCS based on a distributed type, or
may be performed at the GRS based on the distributed type and at
the GCS based on the centralized type.
[0288] Dissimilar to the P2P type, in the case of the P2MP type, a
new network may be present. Thus, a different assignment method may
be additionally employed based on a role of a control station, a
network, and the spectrum authority.
[0289] For example, a channel assignment method in which the
spectrum authority statically assigns a bandwidth to the GRS and
the GRS functions as the spectrum authority may be applied. If the
bandwidth is statically assigned to the GRS in a situation in which
uplink/downlink frequency bandwidths are asymmetric, the above
channel assignment method may inefficiently use a CNPC spectrum in
the entire national airspace volume.
[0290] As another example, a channel assignment method in which the
GRS directly requests the spectrum authority for a CNPC channel
based on requirements of GCSs for the GRS may be applied. If the
GRS requests a channel, the spectrum authority may have difficulty
in stably operating the unmanned aircraft in the nation airspace
volume and a CNPC channel used at each GCS.
[0291] FIG. 7 is a block diagram illustrating a computing system to
execute a dynamic channel assignment and change method and
procedure for controlling an unmanned aircraft according to example
embodiments.
[0292] Referring to FIG. 7, a computing system 1000 may include at
least one processor 1100, a memory 1300, a user interface input
device 1400, a user interface output device 1500, a storage 1600,
and a network interface 1700 that are connected through a system
bus 1200.
[0293] The processor 1100 may be a semiconductor device configured
to process instructions stored in a central processing unit (CPU)
or the memory 1300 and/or the storage 1600. The memory 1300 and the
storage 1600 may include various types of volatile or nonvolatile
storage media. For example, the memory 1300 may include read only
memory (ROM) 1310 and random access memory (RAM) 1320.
[0294] The methods and the operations of the algorithms according
to the example embodiments may be configured through a hardware
module, a software module, and/or a combination thereof by way of
the processor 1100. The software module may be provided to storage
media, for example, the memory 1300 and/or the storage, 1600.
Examples of the storage media may include a RAM memory, a flash
memory, a ROM memory, an erasable programmable ROM (EPROM) memory,
an electrically erasable programmable ROM (EEPROM) memory, a
register, a hard disk, a detachable disk, CD-ROM, etc. The storage
media may be coupled with the processor 1100, and the processor
1100 may read information from the storage media and write
information in the storage media. As another example, the storage
media and the processor 1100 may be provided in an integral type.
The processor 1100 and the storage media may be present in an
application specific integrated circuit (ASIC). The ASIC may be
present in a user terminal. Also, the processor 1100 and the
storage media may be present as individual components within the
user terminal.
[0295] The components described in the exemplary embodiments of the
present invention may be achieved by hardware components including
at least one DSP (Digital Signal Processor), a processor, a
controller, an ASIC (Application Specific Integrated Circuit), a
programmable logic element such as an FPGA (Field Programmable Gate
Array), other electronic devices, and combinations thereof. At
least some of the functions or the processes described in the
exemplary embodiments of the present invention may be achieved by
software, and the software may be recorded on a recording medium.
The components, the functions, and the processes described in the
exemplary embodiments of the present invention may be achieved by a
combination of hardware and software.
[0296] The processing device described herein may be implemented
using hardware components, software components, and/or a
combination thereof. For example, the processing device and the
component described herein may be implemented using one or more
general-purpose or special purpose computers, such as, for example,
a processor, a controller and 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 responding to and
executing instructions in a defined manner. The processing device
may run an operating system (OS) and one or more software
applications that run on the OS. The processing device also may
access, store, manipulate, process, and create data in response to
execution of the software. For purpose of simplicity, the
description of a processing device is used as singular; however,
one skilled in the art will be appreciated that a processing device
may include multiple processing elements and/or multiple types of
processing elements. For example, a processing device may include
multiple processors or a processor and a controller. In addition,
different processing configurations are possible, such as parallel
processors.
[0297] The methods according to the above-described example
embodiments may be recorded in non-transitory computer-readable
media including program instructions to implement various
operations of the above-described example embodiments. The media
may also include, alone or in combination with the program
instructions, data files, data structures, and the like. The
program instructions recorded on the media may be those specially
designed and constructed for the purposes of example embodiments,
or they may be of the kind well-known and available to those having
skill in the computer software arts. Examples of non-transitory
computer-readable media include magnetic media such as hard disks,
floppy disks, and magnetic tape; optical media such as CD-ROM
discs, DVDs, and/or Blue-ray discs; magneto-optical media such as
optical discs; and hardware devices that are specially configured
to store and perform program instructions, such as read-only memory
(ROM), random access memory (RAM), flash memory (e.g., USB flash
drives, memory cards, memory sticks, etc.), and the like. Examples
of program instructions include both machine code, such as produced
by a compiler, and files containing higher level code that may be
executed by the computer using an interpreter. The above-described
devices may be configured to act as one or more software modules in
order to perform the operations of the above-described example
embodiments, or vice versa.
[0298] A number of example embodiments have been described above.
Nevertheless, it should be understood that various modifications
may be made to these example embodiments. For example, suitable
results may be achieved if the described techniques are performed
in a different order and/or if components in a described system,
architecture, device, or circuit are combined in a different manner
and/or replaced or supplemented by other components or their
equivalents. Accordingly, other implementations are within the
scope of the following claims.
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