U.S. patent application number 15/870833 was filed with the patent office on 2018-07-26 for communication node for scheduling and interference control in wireless communication network, and operation method therefor.
This patent application is currently assigned to ELECTRONICS AND TELECOMMUNICATIONS RESEARCH INSTIT UTE. The applicant listed for this patent is ELECTRONICS AND TELECOMMUNICATIONS RESEARCH INSTITUTE. Invention is credited to Dong Hyuk GWAK, Hyung Sik JU, Seon Ae KIM, Yu Ro LEE.
Application Number | 20180213547 15/870833 |
Document ID | / |
Family ID | 62907430 |
Filed Date | 2018-07-26 |
United States Patent
Application |
20180213547 |
Kind Code |
A1 |
JU; Hyung Sik ; et
al. |
July 26, 2018 |
COMMUNICATION NODE FOR SCHEDULING AND INTERFERENCE CONTROL IN
WIRELESS COMMUNICATION NETWORK, AND OPERATION METHOD THEREFOR
Abstract
An operation method of a base station in an IFD scheme may
comprise receiving position information of each of a plurality of
downlink (DL) terminals and a plurality of uplink (UL) terminals;
determining a guard zone corresponding to each of the plurality of
DL terminals based on the position information of each of the
plurality of DL terminals; determining whether at least one UL
terminal is located in the guard zone based on the position
information of each of the plurality of UL terminals; determining a
scheduling priority of each of the plurality of DL terminals
according to whether at least one UL terminal is located in the
guard zone; generating DL control information including
frequency-time resource allocation information and interference
control information based on the determined scheduling priority;
and transmitting data signals and the DL control information to the
plurality of DL terminals.
Inventors: |
JU; Hyung Sik; (Hwaseong-si,
KR) ; GWAK; Dong Hyuk; (Daejeon, KR) ; KIM;
Seon Ae; (Daejeon, KR) ; LEE; Yu Ro; (Daejeon,
KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ELECTRONICS AND TELECOMMUNICATIONS RESEARCH INSTITUTE |
Daejeon |
|
KR |
|
|
Assignee: |
ELECTRONICS AND TELECOMMUNICATIONS
RESEARCH INSTIT UTE
Daejeon
KR
|
Family ID: |
62907430 |
Appl. No.: |
15/870833 |
Filed: |
January 12, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W 72/1242 20130101;
H04L 5/0044 20130101; H04W 72/042 20130101; H04L 5/0037 20130101;
H04L 5/14 20130101; H04W 72/1226 20130101; H04W 72/048 20130101;
H04L 5/0069 20130101; H04W 72/044 20130101; H04W 72/121
20130101 |
International
Class: |
H04W 72/12 20060101
H04W072/12; H04L 5/14 20060101 H04L005/14; H04L 5/00 20060101
H04L005/00; H04W 72/04 20060101 H04W072/04 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 26, 2017 |
KR |
10-2017-0012644 |
Dec 6, 2017 |
KR |
10-2017-0166729 |
Claims
1. An operation method of a base station in an in-band full duplex
(IFD) scheme, the operation method comprising: receiving position
information of each of a plurality of downlink (DL) terminals and a
plurality of uplink (UL) terminals; determining a guard zone
corresponding to each of the plurality of DL terminals based on the
position information of each of the plurality of DL terminals;
determining whether at least one UL terminal is located in the
guard zone based on the position information of each of the
plurality of UL terminals; determining a scheduling priority of
each of the plurality of DL terminals according to whether at least
one UL terminal is located in the guard zone; generating DL control
information including frequency-time resource allocation
information and interference control information based on the
determined scheduling priority; and transmitting data signals and
the DL control information to the plurality of DL terminals.
2. The operation method according to claim 1, wherein the
determining a scheduling priority further comprises: when a first
UL terminal is located in a first guard zone in which a first DL
terminal is centered, generating first frequency-time resource
allocation information for allocating a resource to the first DL
terminal and the first DL terminal; generating first pairing
information indicating that the first DL terminal and the first UL
terminal use a same frequency-time resource; and generating first
interference control information instructing interference
cancellation.
3. The operation method according to claim 2, wherein the
generating DL control information further comprises generating
first DL control information including the first frequency-time
resource allocation information, the first paring information, and
the first interference control information, and the transmitting
data signals and the DL control information further comprises
transmitting a first data signal and the first DL control
information to the first DL terminal.
4. The operation method according to claim 1, wherein the
determining a scheduling priority further comprises, when a second
UL terminal and a third UL terminal are located in a second guard
zone in which a second DL terminal is centered, determining a UL
terminal using a same frequency-time resource with the second DL
terminal based on position information of the second UL terminal
and the third UL terminal.
5. The operation method according to claim 4, wherein the
determining a scheduling priority further comprises, when a
distance between the second DL terminal and the second UL terminal
is smaller than a distance between the second DL terminal and the
third UL terminal, determining the second UL terminal as a UL
terminal using a same frequency-time resource with the second DL
terminal.
6. The operation method according to claim 5, wherein the
determining a scheduling priority further comprises: generating
second frequency-time resource allocation information for
allocating a resource to the second DL terminal and the second UL
terminal; generating second pairing information indicating that the
second DL terminal and the second UL terminal use a same
frequency-time resource; and generating second interference control
information instructing interference cancellation.
7. The operation method according to claim 6, wherein the
generating DL control information further comprises generating
second DL control information including the second frequency-time
resource allocation information, the second paring information, and
the second interference control information, and the transmitting
data signals and the DL control information further comprises
transmitting a second data signal and the second DL control
information to the second DL terminal.
8. The operation method according to claim 4, wherein the
determining a scheduling priority further comprises, when a UL
terminal is not located in a third guard zone in which the third DL
terminal is centered, determining a UL terminal using a same
frequency-time resource with the third DL terminal based on
position information of the third UL terminal and position
information of a fourth UL terminal which is not located in the
third guard zone.
9. The operation method according to claim 8, wherein the
determining a scheduling priority further comprises, when a
distance between the third DL terminal and the third UL terminal is
larger than a distance between the third DL terminal and the fourth
UL terminal, determining the third UL terminal as a UL terminal
using a same frequency-time resource with the third DL
terminal.
10. The operation method according to claim 9, wherein the
determining a scheduling priority further comprises: generating
third frequency-time resource allocation information for allocating
a resource to the third DL terminal and the third UL terminal;
generating third pairing information indicating that the third DL
terminal and the third UL terminal use a same frequency-time
resource; and generating third interference control information
instructing interference cancellation, wherein the generating DL
control information further comprises generating third DL control
information including the third frequency-time resource allocation
information, the third paring information, and the third
interference control information, and the transmitting data signals
and the DL control information further comprises transmitting a
third data signal and the third DL control information to the third
DL terminal.
11. An operation method of a terminal receiving data signal from a
base station operating in an in-band full duplex (IFD) scheme, the
operation method comprising: transmitting position information of
the terminal to the base station; receiving, from the base station,
frequency-time resource allocation information, pairing
information, and interference control information; and determining
whether to perform an interference cancellation operation based on
the interference control information.
12. The operation method according to claim 11, wherein the
frequency-time resource allocation information includes information
on a frequency-time resource allocated to the terminal, the pairing
information includes identification information of another terminal
using a same frequency-time resource with the terminal, and the
interference control information includes information instructing
whether to perform an interference cancellation operation when the
data signal is received.
13. The operation method according to claim 12, wherein the
interference control information is generated based on the position
information of the terminal and the another terminal, includes
information instructing to perform the interference cancellation
operation when a distance between the terminal and the another
terminal is less than a threshold, and includes information
instructing not to perform the interference cancellation operation
when the distance between the terminal and the another terminal
exceeds a threshold.
14. The operation method according to claim 12, wherein the
determining further comprises receiving the data signal by
performing the interference cancellation operation when the
interference control information includes information instructing
to perform the interference cancellation operation.
15. The operation method according to claim 12, wherein the
determining further comprises receiving the data signal without
performing the interference cancellation operation when the
interference control information includes information instructing
not to perform the interference cancellation operation.
16. A terminal receiving data signal from a base station operating
in an in-band full duplex (IFD) manner, the terminal comprising a
processor and a memory storing at least one instruction executed by
the processor, wherein the at least one instruction is configured
to: transmit position information of the terminal to the base
station; receive, from the base station, frequency-time resource
allocation information, pairing information, and interference
control information; and determine whether to perform an
interference cancellation operation based on the interference
control information.
17. The terminal according to claim 16, wherein the frequency-time
resource allocation information includes information on a
frequency-time resource allocated to the terminal, the pairing
information includes identification information of another terminal
using a same frequency-time resource with the terminal, and the
interference control information includes information instructing
whether to perform an interference cancellation operation when the
data signal is received.
18. The terminal according to claim 17, wherein the interference
control information is generated based on the position information
of the terminal and the another terminal, includes information
instructing to perform the interference cancellation operation when
a distance between the terminal and the another terminal is less
than a threshold, and includes information instructing not to
perform the interference cancellation operation when the distance
between the terminal and the another terminal exceeds a
threshold.
19. The terminal according to claim 17, wherein the at least one
instruction is further configured to receive the data signal by
performing the interference cancellation operation when the
interference control information includes information instructing
to perform the interference cancellation operation.
20. The terminal according to claim 17, wherein the at least one
instruction is further configured to receive the data signal
without performing the interference cancellation operation when the
interference control information includes information instructing
not to perform the interference cancellation operation.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priorities to Korean Patent
Applications No. 10-2017-0012644 filed on Jan. 26, 2017 and No.
10-2017-0166729 filed on Dec. 6, 2017 in the Korean Intellectual
Property Office (KIPO), the entire contents of which are hereby
incorporated by reference.
BACKGROUND
1. Technical Field
[0002] The present disclosure relates to a wireless communication
network, and more specifically, to a communication node for
scheduling and interference control in a wireless communication
network and an operation method of the communication node.
2. Related Art
[0003] In a wireless communication network, a base station may
operate in various duplexing schemes. For example, a base station
may operate in an in-band full duplex (IFD) or half duplex (HD)
scheme. The base station operating in the IFD scheme may transmit
and receive signals to and from at least one terminal operating in
the HD scheme. For example, the base station operating in the IFD
scheme may transmit a data signal to a terminal through a downlink
resource. Also, the base station operating in the IFD scheme may
receive a data signal from a terminal through an uplink resource
which is the same as the downlink resource at the same time. That
is, the base station operating in the IFD scheme may perform
downlink transmission and uplink reception using the same
frequency-time resources.
[0004] However, self-interference (SI) due to a data signal
transmitted through the downlink may affect a data signal received
through the uplink. Accordingly, the base stations operating in the
IFD scheme may experience reduced spectral efficiency due to the
SI.
SUMMARY
[0005] Accordingly, embodiments of the present disclosure provide
an operation method of a communication node for performing
scheduling and interference control to enhance downlink performance
and uplink performance in a wireless communication network.
[0006] Also, embodiments of the present disclosure provide a
communication node for performing scheduling and interference
control to enhance downlink performance and uplink performance in a
wireless communication network.
[0007] In order to achieve the objective of the present disclosure,
an operation method of a base station in an in-band full duplex
(IFD) scheme may comprise receiving position information of each of
a plurality of downlink (DL) terminals and a plurality of uplink
(UL) terminals; determining a guard zone corresponding to each of
the plurality of DL terminals based on the position information of
each of the plurality of DL terminals; determining whether at least
one UL terminal is located in the guard zone based on the position
information of each of the plurality of UL terminals; determining a
scheduling priority of each of the plurality of DL terminals
according to whether at least one UL terminal is located in the
guard zone; generating DL control information including
frequency-time resource allocation information and interference
control information based on the determined scheduling priority;
and transmitting data signals and the DL control information to the
plurality of DL terminals.
[0008] The determining a scheduling priority may further comprise
when a first UL terminal is located in a first guard zone in which
a first DL terminal is centered, generating first frequency-time
resource allocation information for allocating a resource to the
first DL terminal and the first DL terminal; generating first
pairing information indicating that the first DL terminal and the
first UL terminal use a same frequency-time resource; and
generating first interference control information instructing
interference cancellation.
[0009] The generating DL control information may further comprise
generating first DL control information including the first
frequency-time resource allocation information, the first paring
information, and the first interference control information, and
the transmitting data signals and the DL control information may
further comprise transmitting a first data signal and the first DL
control information to the first DL terminal.
[0010] The determining a scheduling priority may further comprise,
when a second UL terminal and a third UL terminal are located in a
second guard zone in which a second DL terminal is centered,
determining a UL terminal using a same frequency-time resource with
the second DL terminal based on position information of the second
UL terminal and the third UL terminal.
[0011] The determining a scheduling priority may further comprise,
when a distance between the second DL terminal and the second UL
terminal is smaller than a distance between the second DL terminal
and the third UL terminal, determining the second UL terminal as a
UL terminal using a same frequency-time resource with the second DL
terminal.
[0012] The determining a scheduling priority may further comprise
generating second frequency-time resource allocation information
for allocating a resource to the second DL terminal and the second
UL terminal; generating second pairing information indicating that
the second DL terminal and the second UL terminal use a same
frequency-time resource; and generating second interference control
information instructing interference cancellation.
[0013] The generating DL control information may further comprise
generating second DL control information including the second
frequency-time resource allocation information, the second paring
information, and the second interference control information, and
the transmitting data signals and the DL control information may
further comprise transmitting a second data signal and the second
DL control information to the second DL terminal.
[0014] The determining a scheduling priority may further comprise,
when a UL terminal is not located in a third guard zone in which
the third DL terminal is centered, determining a UL terminal using
a same frequency-time resource with the third DL terminal based on
position information of the third UL terminal and position
information of a fourth UL terminal which is not located in the
third guard zone.
[0015] The determining a scheduling priority may further comprise,
when a distance between the third DL terminal and the third UL
terminal is larger than a distance between the third DL terminal
and the fourth UL terminal, determining the third UL terminal as a
UL terminal using a same frequency-time resource with the third DL
terminal.
[0016] The determining a scheduling priority further comprise
generating third frequency-time resource allocation information for
allocating a resource to the third DL terminal and the third UL
terminal; generating third pairing information indicating that the
third DL terminal and the third UL terminal use a same
frequency-time resource; and generating third interference control
information instructing interference cancellation. Here, the
generating DL control information may further comprise generating
third DL control information including the third frequency-time
resource allocation information, the third paring information, and
the third interference control information, and the transmitting
data signals and the DL control information may further comprise
transmitting a third data signal and the third DL control
information to the third DL terminal.
[0017] In order to achieve the objective of the present disclosure,
an operation method of a terminal receiving data signal from a base
station operating in an in-band full duplex (IFD) scheme may
comprise transmitting position information of the terminal to the
base station; receiving, from the base station, frequency-time
resource allocation information, pairing information, and
interference control information; and determining whether to
perform an interference cancellation operation based on the
interference control information.
[0018] The frequency-time resource allocation information may
include information on a frequency-time resource allocated to the
terminal, the pairing information may include identification
information of another terminal using a same frequency-time
resource with the terminal, and the interference control
information may include information instructing whether to perform
an interference cancellation operation when the data signal is
received.
[0019] The interference control information may be generated based
on the position information of the terminal and the another
terminal, include information instructing to perform the
interference cancellation operation when a distance between the
terminal and the another terminal is less than a threshold, and
include information instructing not to perform the interference
cancellation operation when the distance between the terminal and
the another terminal exceeds a threshold.
[0020] The determining may further comprise receiving the data
signal by performing the interference cancellation operation when
the interference control information includes information
instructing to perform the interference cancellation operation.
[0021] The determining may further comprise receiving the data
signal without performing the interference cancellation operation
when the interference control information includes information
instructing not to perform the interference cancellation
operation.
[0022] In order to achieve the objective of the present disclosure,
a terminal receiving data signal from a base station operating in
an in-band full duplex (IFD) manner may comprise a processor and a
memory storing at least one instruction executed by the processor.
Also, the at least one instruction may be configured to transmit
position information of the terminal to the base station; receive,
from the base station, frequency-time resource allocation
information, pairing information, and interference control
information; and determine whether to perform an interference
cancellation operation based on the interference control
information.
[0023] The frequency-time resource allocation information may
include information on a frequency-time resource allocated to the
terminal, the pairing information may include identification
information of another terminal using a same frequency-time
resource with the terminal, and the interference control
information may include information instructing whether to perform
an interference cancellation operation when the data signal is
received.
[0024] The interference control information may be generated based
on the position information of the terminal and the another
terminal, include information instructing to perform the
interference cancellation operation when a distance between the
terminal and the another terminal is less than a threshold, and
include information instructing not to perform the interference
cancellation operation when the distance between the terminal and
the another terminal exceeds a threshold.
[0025] The at least one instruction may be further configured to
receive the data signal by performing the interference cancellation
operation when the interference control information includes
information instructing to perform the interference cancellation
operation.
[0026] The at least one instruction may be further configured to
receive the data signal without performing the interference
cancellation operation when the interference control information
includes information instructing not to perform the interference
cancellation operation.
[0027] According to the embodiments of the present disclosure, a
communication node in a wireless communication network may improve
downlink performance and uplink performance through scheduling and
interference control, thereby improving the communication
performance of the entire wireless communication network.
BRIEF DESCRIPTION OF DRAWINGS
[0028] Embodiments of the present disclosure will become more
apparent by describing in detail embodiments of the present
disclosure with reference to the accompanying drawings, in
which:
[0029] FIG. 1 is a conceptual diagram illustrating a first
embodiment of a cellular communication system;
[0030] FIG. 2 is a block diagram illustrating a first embodiment of
a communication node constituting a cellular communication
system;
[0031] FIG. 3 is a conceptual diagram illustrating a second
embodiment of a cellular communication network;
[0032] FIG. 4 is a sequence chart illustrating signal flows between
a base station and terminals in a second embodiment of a cellular
communication network;
[0033] FIGS. 5A and 5B are flowcharts for explaining an operation
method of a base station according to an embodiment of the present
disclosure;
[0034] FIG. 6 is a flowchart for explaining an operation method of
a downlink terminal according to a second embodiment of the present
disclosure;
[0035] FIG. 7 is a conceptual diagram illustrating exemplary
positions of a base station and a plurality of terminals located in
a cell;
[0036] FIG. 8 is a graph for comparing downlink performances of
different operating modes including an operating mode based on
scheduling and interference control proposed by the present
disclosure; and
[0037] FIG. 9 is a graph for comparing downlink performance
increments of different operating modes including an operating mode
based on scheduling and interference control proposed by the
present disclosure.
DETAILED DESCRIPTION
[0038] Embodiments of the present disclosure are disclosed herein.
However, specific structural and functional details disclosed
herein are merely representative for purposes of describing
embodiments of the present disclosure, however, embodiments of the
present disclosure may be embodied in many alternate forms and
should not be construed as limited to embodiments of the present
disclosure set forth herein.
[0039] Accordingly, while the present disclosure is susceptible to
various modifications and alternative forms, specific embodiments
thereof are shown by way of example in the drawings and will herein
be described in detail. It should be understood, however, that
there is no intent to limit the present disclosure to the
particular forms disclosed, but on the contrary, the present
disclosure is to cover all modifications, equivalents, and
alternatives falling within the spirit and scope of the present
disclosure. Like numbers refer to like elements throughout the
description of the figures.
[0040] It will be understood that, although the terms first,
second, etc. may be used herein to describe various elements, these
elements should not be limited by these terms. These terms are only
used to distinguish one element from another. For example, a first
element could be termed a second element, and, similarly, a second
element could be termed a first element, without departing from the
scope of the present disclosure. As used herein, the term "and/or"
includes any and all combinations of one or more of the associated
listed items.
[0041] It will be understood that when an element is referred to as
being "connected" or "coupled" to another element, it can be
directly connected or coupled to the other element or intervening
elements may be present. In contrast, when an element is referred
to as being "directly connected" or "directly coupled" to another
element, there are no intervening elements present. Other words
used to describe the relationship between elements should be
interpreted in a like fashion (i.e., "between" versus "directly
between," "adjacent" versus "directly adjacent," etc.).
[0042] The terminology used herein is for the purpose of describing
particular embodiments only and is not intended to be limiting of
the present disclosure. As used herein, the singular forms "a,"
"an" and "the" are intended to include the plural forms as well,
unless the context clearly indicates otherwise. It will be further
understood that the terms "comprises," "comprising," "includes"
and/or "including," when used herein, specify the presence of
stated features, integers, steps, operations, elements, and/or
components, but do not preclude the presence or addition of one or
more other features, integers, steps, operations, elements,
components, and/or groups thereof.
[0043] 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
present disclosure belongs. It will be further understood that
terms, such as those defined in commonly used dictionaries, should
be interpreted as having a meaning that is consistent with their
meaning in the context of the relevant art and will not be
interpreted in an idealized or overly formal sense unless expressly
so defined herein.
[0044] Hereinafter, embodiments of the present disclosure will be
described in greater detail with reference to the accompanying
drawings. In order to facilitate general understanding in
describing the present disclosure, the same components in the
drawings are denoted with the same reference signs, and repeated
description thereof will be omitted.
[0045] Hereinafter, wireless communication networks to which
exemplary embodiments according to the present disclosure will be
described. However, wireless communication networks to which
exemplary embodiments according to the present disclosure are
applied are not restricted to what will be described below. That
is, exemplary embodiments according to the present disclosure may
be applied to various wireless communication networks.
[0046] FIG. 1 is a conceptual diagram illustrating a first
embodiment of a cellular communication system.
[0047] Referring to FIG. 1, a communication system 100 may comprise
a plurality of communication nodes 110-1, 110-2, 110-3, 120-1,
120-2, 130-1, 130-2, 130-3, 130-4, 130-5, and 130-6. Also, the
communication system 100 may comprise a core network (e.g., a
serving gateway (S-GW), a packet data network (PDN) gateway (P-GW),
a mobility management entity (MME), and the like).
[0048] The plurality of communication nodes may support 4.sup.th
generation (4G) communication (e.g., long term evolution (LTE),
LTE-advanced (LTE-A)), or 5.sup.th generation (5G) communication
defined in the 3.sup.rd generation partnership project (3GPP)
standard. The 4G communication may be performed in a frequency band
below 6 gigahertz (GHz), and the 5G communication may be performed
in a frequency band above 6 GHz. For example, for the 4G and 5G
communications, the plurality of communication nodes may support at
least one communication protocol among a code division multiple
access (CDMA) based communication protocol, a wideband CDMA (WCDMA)
based communication protocol, a time division multiple access
(TDMA) based communication protocol, a frequency division multiple
access (FDMA) based communication protocol, an orthogonal frequency
division multiplexing (OFDM) based communication protocol, an
orthogonal frequency division multiple access (OFDMA) based
communication protocol, a single carrier FDMA (SC-FDMA) based
communication protocol, a non-orthogonal multiple access (NOMA)
based communication protocol, and a space division multiple access
(SDMA) based communication protocol. Also, each of the plurality of
communication nodes may have the following structure.
[0049] FIG. 2 is a block diagram illustrating a first embodiment of
a communication node constituting a cellular communication
system.
[0050] Referring to FIG. 2, a communication node 200 may comprise
at least one processor 210, a memory 220, and a transceiver 230
connected to the network for performing communications. Also, the
communication node 200 may further comprise an input interface
device 240, an output interface device 250, a storage device 260,
and the like. Each component included in the communication node 200
may communicate with each other as connected through a bus 270.
[0051] The processor 210 may execute a program stored in at least
one of the memory 220 and the storage device 260. The processor 210
may refer to a central processing unit (CPU), a graphics processing
unit (GPU), or a dedicated processor on which methods in accordance
with embodiments of the present disclosure are performed. Each of
the memory 220 and the storage device 260 may be constituted by at
least one of a volatile storage medium and a non-volatile storage
medium. For example, the memory 220 may comprise at least one of
read-only memory (ROM) and random access memory (RAM).
[0052] FIG. 3 is a conceptual diagram illustrating a second
embodiment of a cellular communication network.
[0053] Referring to FIG. 3, a second embodiment of a communication
network may be a mobile communication network. The communication
network may include a base station 310, a first terminal 320, and a
second terminal 330. The base station 310 may operate in an in-band
full duplex (IFD) scheme. Also, the first terminal 320 and the
second terminal 330 may operate in a half duplex (HD) scheme.
[0054] The base station 310 may simultaneously use downlink (DL)
and uplink (UL) in a predetermined frequency-time resource. That
is, the base station 310 may simultaneously transmit and receive
signals at the predetermined frequency-time resource. For example,
the base station 310 may receive a UL signal from the second
terminal 330 while transmitting a DL signal to the first terminal
320. Here, the base station 310 may remove self-interference (SI)
generated by transmitting the DL signal.
[0055] Since the base station 310 may simultaneously transmit and
receive signals over the same frequency-time resource in the IFD
scheme, the base station 310 may improve a spectral efficiency of
each link by up to twice as much as that of the HD scheme in an
ideal environment. However, when the base station 310 transmits a
signal through the DL, due to the SI caused by the IFD scheme, a
reception performance through the UL may be degraded. Also, when
the base station 310 receives a signal through the UL, co-channel
interference (CCI) may be generated for a signal transmitted
through the DL.
[0056] Therefore, the base station 310 operating in the IFD scheme
may simultaneously degrade the reception performance on the UL and
the transmission performance on the UL. As a result, the spectral
efficiency of the base station of the IFD scheme may be lower than
that of the half-duplex base station.
[0057] FIG. 4 is a sequence chart illustrating signal flows between
a base station and terminals in a second embodiment of a cellular
communication network.
[0058] Referring to FIG. 4, a second embodiment of a communication
network may include a base station 410, a DL terminal 420, and a UL
terminal 430. The base station 410 may operate in the IFD scheme.
Also, the DL terminal 420 and the UL terminal 430 may operate in
the HD scheme.
[0059] Here, the DL terminal 420 may be affected by CCI due to a
transmission signal of the UL terminal 430. Therefore, a DL
performance of the DL terminal 420 may be degraded due to the CCI.
Accordingly, the base station 410 may perform an operation for
reducing deterioration of the DL performance.
[0060] For example, the base station 410 may perform scheduling for
the DL terminal 420 and the UL terminal 430 to reduce deterioration
in the DL performance. Also, the base station 410 may transmit a
predetermined DL reception signal processing indication message to
the DL terminal 420 in order to reduce deterioration of the DL
performance.
[0061] The base station 410 may receive position information from
each of the DL terminal 420 and the UL terminal 430 (S401, S402).
For example, the base station 410 may receive position information
of the DL terminal 420 from the DL terminal 420 (S401). Also, the
base station 410 may receive position information of the UL
terminal 430 from the UL terminal 430 (S402).
[0062] The base station 410 may then perform clustering and
scheduling (S403). For example, the base station 410 may perform
clustering and scheduling for the DL terminal 420 and the UL
terminal 430 based on the position information of the DL terminal
420 and the UL terminal 430 (S403). The base station 410 may
generate scheduling information through the clustering and
scheduling. The scheduling information may include at least one of
resource allocation information, pairing information, and
interference control information. The base station 410 may transmit
the scheduling information to the DL terminal 420 and the UL
terminal 430.
[0063] The base station 410 may transmit the resource allocation
information to the DL terminal 420 and the UL terminal 430 (S404
and S405). The resource allocation information may include
information on a frequency-time resource allocated to the DL
terminal 420 or the UL terminal 420. For example, the base station
410 may transmit to the DL terminal 420 the resource allocation
information including information on at least one subframe or slot
allocated to the DL terminal 420 (S404). Also, the base station 410
may transmit to the UL terminal 430 the resource allocation
information on at least one subframe or slot allocated to the UL
terminal 430 (S405).
[0064] The base station 410 may transmit the pairing information to
the DL terminal 420 (S406). For example, the pairing information
may be denoted as `ConcurULUE.ID`. That is, `ConcurULUE.ID` may
indicate the pairing information. For example, the pairing
information may include information on a UL terminal to be paired
with the DL terminal 420. That is, the pairing information may
include information on a UL terminal using the same channel with
the DL terminal 420. For example, the pairing information may
include identification information (e.g., ID) of the UL terminal
using the same channel with the DL terminal 420.
[0065] The base station 410 may transmit the interference control
information to the DL terminal 420 (S407). The interference control
information may be denoted as `SCCIC.Ind`. That is, `SCCIC.Ind` may
indicate the interference control information. For example, the
interference control information may indicate whether or not the DL
terminal 420 is required to perform a successive co-channel
interference cancellation (SCCIC) operation when the DL terminal
420 receives a data signal from the base station 410 through the
DL. For example, the interference control information may be
information of a size of 1 bit.
[0066] The base station 410 may receive a response message from
each of the DL terminal 420 and the UL terminal 430 (S408 and
S409). The response message may be denoted as `acknowledgement
(ACK)`. For example, the DL terminal 420 may transmit to the base
station 410 a response message indicating that the resource
allocation information has been received to the base station
(S408). Also, the UL terminal 430 may transmit to the base station
410 a response message informing that the UL terminal 430 has
received the resource allocation information, the pairing
information, and the interference control information (S409).
[0067] The base station 410 may transmit and receive data signals
to the DL terminal 420 and the UL terminal 430 (S410 and S411). For
example, when the base station 410 receives the response message
from the DL terminal 420, the base station 410 may transmit a data
signal to the DL terminal 420 through the DL (S410). For example,
the DL terminal 420 may receive the data signal from the base
station 410 through a frequency-time resource allocated based on
the resource allocation information. Also, when the base station
410 receives the response message from the UL terminal 430, the
base station 410 may receive a data signal from the UL terminal 430
through the UL (S411). For example, the UL terminal 430 may
transmit the data signal to the base station 410 through a
frequency-time resource allocated based on the resource allocation
information.
[0068] The DL terminal 420 may control interference according to
the interference control information (S412). The DL terminal 420
may identify the interference control information. The interference
control information may include a value of `0` or `1`. For example,
if the value of the interference control information is `1`, the DL
terminal 420 may perform the SCCIC operation.
[0069] For example, if the value of `SCCIC.Ind` is `1`, the DL
terminal 420 may perform the SCCIC operation. For example, the DL
terminal 420 may perform interference cancellation on the DL data
signal received through the allocated frequency-time resource.
Here, the DL terminal 420 may acquire data from the
interference-canceled DL data signal. On the other hand, if the
value of the interference control information is `0`, the DL
terminal 420 may not perform the SCCIC operation.
[0070] FIGS. 5A and 5B are flowcharts for explaining an operation
method of a base station according to an embodiment of the present
disclosure.
[0071] Referring to FIG. 5A, a base station may perform clustering
and scheduling based on a user pairing algorithm. The base station
may receive position information of terminals (S501). A plurality
of DL terminals and a plurality of UL terminals may exist in a cell
where the base station is located. Here, the base station may
receive position information from each of the plurality of DL
terminals and the plurality of UL terminals.
[0072] The base station may determine a guard zone based on the
position information of each of the DL terminals (S502). For
example, the base station may configure a circle having a radius R
around the position of the DL terminal based on the position
information of the DL terminal. Here, R may be a predetermined
constant. The circle with radius R may be referred to as the guard
zone.
[0073] The base station may determine whether at least one UL
terminal is located in the guard zone (S503). The base station may
represent distances between the respective DL terminals and the
respective UL terminals in the cell as a matrix D(i, j). The
element D(i, j) may indicate a distance between an i-th DL terminal
and a j-th UL terminal in the cell. The base station may determine
a condition matrix C based on the matrix D(i, j) as shown in
Equation 1 below.
C ( i , j ) = { 1 , if D ( i , j ) .ltoreq. R , 0 , otherwise . [
Equation 1 ] ##EQU00001##
[0074] The base station may repeatedly perform pairing for each of
the DL terminals and each of the UL terminals to allocate each time
slot by updating the matrix C and the matrix D.
[0075] For example, the base station may determine .omega..sub.t
based on the condition matrix C as shown in Equation 2 below. Here,
.A-inverted.=1, . . . , K.
.omega..sub.t=.SIGMA..sub.i=1.sup.K.SIGMA..sub.j=J.sup.KC(i,j).
[Equation 2]
[0076] The base station may determine that there is no UL terminal
belonging to a guard zone of a DL terminal when .omega..sub.t=0. On
the other hand, the base station may determine that there exists a
UL terminal located in a guard zone of a DL terminal when
.omega..sub.t>0.
[0077] The base station may determine a DL terminal having a guard
zone where a UL terminal exists (S504).
[0078] The base station may perform the pairing of a DL terminal
and a UL terminal differently according to the case where
.omega..sub.t=0 and the case where .omega..sub.t>0. For example,
if .omega..sub.t>0, the base station may determine a set of DL
terminals having a guard zone where a UL terminal is located.
[0079] The base station may determine the number of UL terminals in
the guard zone (S505).
[0080] The base station may determine .alpha..sub.t(i) as shown in
Equation 3 below. Here, i=1, 2, . . . , K.
.alpha. t ( i ) = { .infin. , if .theta. t ( i ) = 0 , .theta. t (
i ) , if .theta. t ( i ) .noteq. 0 , [ Equation 3 ]
##EQU00002##
[0081] Here, the base station may determine .theta..sub.t(i) as
shown in Equation 3 below.
.theta..sub.t(i)=.SIGMA..sub.j=1.sup.KC(i,j) [Equation 4]
[0082] .theta..sub.t(i) may denote the number of UL terminals
existing in the guard zone of the i-th DL terminal.
[0083] The base station may determine a scheduling priority based
on the number of UL terminals (S506).
[0084] The base station may assign a higher scheduling priority to
a DL terminal having the smaller number of UL terminals in the
guard zone among a set of DL terminals. For example, the highest
scheduling priority may be assigned to a DL terminal having the
smallest number of UL terminal in its guard zone. That is, the base
station may preferentially schedule a DL terminal having the
smallest number of UL terminals in the guard zone among the set of
DL terminals. The base station may determine a DL terminal for
scheduling according to the scheduling priority. Also, the base
station may determine a UL terminal to be paired with the DL
terminal for which scheduling has been determined.
[0085] For example, the base station may select a d.sub.t-th DL
terminal as the DL terminal for scheduling. The base station may
determine d.sub.t through Equation 5 below.
d.sub.t=arg min [.alpha..sub.t(1), .alpha..sub.t(2), . . . m
.alpha..sub.t(K)].sup.T. [Equation 5]
[0086] The base station may determine d.sub.t as d.sub.t=i or
d.sub.t=j if i and j are present. Here, i.noteq.j and
.alpha..sub.t(i)=.alpha..sub.t(j). Also, the choice of d.sub.t=i or
d.sub.t=j may not affect the performance of the proposed user
pairing algorithm.
[0087] The base station may perform pairing based on the distances
between the respective UL terminals and the respective DL terminals
(S507).
[0088] The base station may define two vectors .beta..sub.t and
.delta..sub.t to select a UL terminal to be paired with the
d.sub.t-th DL terminal. Here, .beta..sub.t=[.beta..sub.t(1),
.beta..sub.t(2), . . . , .beta..sub.t(k)] and
.delta..sub.t=[.delta..sub.t(1), .delta..sub.t(2), . . . ,
.delta..sub.t(k)]. .beta..sub.t and .delta..sub.t represent the
d.sub.t-th row of the matrixes C and D, respectively.
[0089] The base station may determine vectors .zeta..sub.t and
.sigma..sub.t based on Equations 6 and 7 below. Here,
.zeta..sub.t=[.zeta..sub.t(1), .zeta..sub.t(2), . . . ,
.zeta..sub.t(k)] and .pi..sub.t=[.sigma..sub.t(1),
.sigma..sub.t(2), . . . , .sigma..sub.t(k)].
.zeta. t ( i ) = { .infin. , if .beta. t ( i ) = 0 , .beta. t ( i )
, if .beta. t ( i ) .noteq. 0 , 1 .ltoreq. i .ltoreq. K , [
Equation 6 ] .sigma. t ( i ) = .zeta. t ( i ) .delta. t ( i ) , 1
.ltoreq. i .ltoreq. K . [ Equation 7 ] ##EQU00003##
[0090] The base station may pair the u.sub.t-th UL terminal and the
d.sub.t-th DL terminal. The base station may determine the
u.sub.t-th UL terminal based on Equation 8 below.
u.sub.t=arg min [.sigma..sub.t(1), .sigma..sub.1(2), . . . ,
.sigma..sub.t(K)].sup.T. [Equation 8]
[0091] When i and j are present, and i.noteq.j,
min[.sigma..sub.t(1), . . . ,
.sigma..sub.t(k)]=.sigma..sub.t(i)=.sigma..sub.t(j). In case that
D(d.sub.t, i)>D(d.sub.t, j), the base station may determine
u.sub.t as u.sub.t=i. This is because a UL terminal remote from the
d.sub.t-th DL terminal may be located in a guard zone of another DL
terminal.
[0092] After determining the pairing of the d.sub.t-th DL terminal
and the u.sub.t-th UL terminal, the base station may update the
condition matrix C as shown in Equations 9 and 10 below to perform
pairing of other DL terminals and other UL terminals.
C(d.sub.t,j)=0, .A-inverted.j=1, 2, . . . , K, [Equation 9]
C(i,u.sub.t)=0, .A-inverted.i=1, 2, . . . , K. [Equation 10]
[0093] The base station may repeat the operations based on the
Equations 2 to 10 when .omega..sub.t>0. The base station may
determine the pairing of the d.sub.t-th DL terminal and the
u.sub.t-th UL terminal based on the condition matrix D when
.omega..sub.t=0. The base station may determine the condition
matrix D based on the following Equations 11 and 12.
D(d.sub.t,j)=0, .A-inverted..tau.=1, 2, . . . , t-1, [Equation
11]
D(i,u.sub.t)=0, .A-inverted..tau.=1, 2, . . . , t-1, [Equation
12]
[0094] The base station may determine d.sub.t and u.sub.t based on
Equation 13 below.
( d t , u t ) = arg max i , j D ( i , j ) . [ Equation 13 ]
##EQU00004##
[0095] The base station may determine whether paring of all
terminals is completed (S508). The base station may repeat the
operations of Equation 2 and Equations 9 to 13 until t =k. That is,
the base station may repeat the operations of Equation 2 and
Equations 9 to 13 until the pairing for all the terminals is
completed.
[0096] If all the terminals are not paired, the base station may
perform the step S507 again.
[0097] If all the terminals are paired, the base station may
proceed to a step S509.
[0098] The base station may generate the resource allocation
information, the pairing information, and the interference control
information (S509). The base station may generate scheduling
information including the resource allocation information, the
pairing information, and the interference control information. The
base station may generate the pairing information and the
interference control information based on the user pairing
algorithm described above. The above-described operations of
Equations 1 to 13 may be referred to as the user pairing
algorithm.
[0099] The resource allocation information may include information
on a frequency-time resource allocated to each of a plurality of DL
terminals and a plurality of UL terminals located in a cell of the
base station. The pairing information may include information about
a paired DL terminal for each of a plurality of UL terminals
located in a cell of the base station. The interference control
information may include information indicating whether each of the
DL terminals performs an interference cancellation operation.
[0100] The base station may transmit the resource allocation
information, the pairing information, and the interference control
information (S510). The base station may transmit the scheduling
information to each of the plurality of DL terminals and the
plurality of DL terminals that have been scheduled. For example,
the base station may transmit the scheduling information including
the resource allocation information, the pairing information, and
the interference control information to each of the plurality of DL
terminals that have been scheduled. Also, the base station may
transmit the scheduling information including resource the resource
allocation information to each of the plurality of UL terminals
that have been scheduled.
[0101] The base station may receive a response message (S511). The
base station may receive a response message indicating that each of
the plurality of UL terminals has received the scheduling
information including the resource allocation information from each
of the plurality of UL terminals. The base station may also receive
a response message from each of the plurality of DL terminals
indicating that each of the plurality of DL terminals has received
the scheduling information including the resource allocation
information, the pairing information, and the interference control
information.
[0102] The base station may transmit and receive data signals
(S512). When a response message is received from each of the
plurality of DL terminals, the base station may transmit a data
signal to each of the plurality of DL terminals. Also, when a
response message is received from each of the plurality of UL
terminals, the base station may receive a data signal from each of
the plurality of UL terminals.
[0103] FIG. 6 is a flowchart for explaining an operation method of
a downlink terminal according to a second embodiment of the present
disclosure.
[0104] Referring to FIG. 6, a DL terminal may transmit its position
information (S601). For example, the DL terminal may generate
position information of the DL terminal based on a predetermined
algorithm. The DL terminal may transmit the position information to
a base station of a cell to which the DL terminal belongs.
[0105] The DL terminal may receive the resource allocation
information, the pairing information, and the interference control
information from the base station (S602). That is, the DL terminal
may receive the scheduling information including the resource
allocation information, the pairing information, and the
interference control information from the base station.
[0106] The resource allocation information may include information
on a subframe or a time slot allocated to the DL terminal. The
pairing information may include information on a UL terminal using
the same channel with the DL terminal. The interference control
information may include information indicating whether the DL
terminal is required to perform an interference cancellation
operation.
[0107] The DL terminal may transmit a response message to the base
station (S603). The DL terminal may transmit to the base station a
response message indicating that scheduling information including
the resource allocation information, the pairing information and
the interference control information has been successfully
received.
[0108] The DL terminal may receive a data signal from the base
station (S604). The DL terminal may receive the data signal from
the base station through the DL of the base station.
[0109] The DL terminal may determine whether to perform the
interference cancellation operation (S605). The DL terminal may
determine whether to perform the interference cancellation
operation based on the interference control information. For
example, if the value of the interference control information is
`0`, the DL terminal may not perform the interference cancellation
operation.
[0110] The DL terminal may perform the interference cancellation
operation (S606). If the value of the interference control
information is `1`, the DL terminal may perform the interference
cancellation operation (S606). The DL terminal may perform the
interference cancellation operation upon receiving the data signal
from the base station. The interference cancellation operation may
be also referred to as the SCCIC operation as described above.
[0111] For example, the DL terminal may decode received signals
sequentially from a signal having the highest received power among
the received signals. The DL terminal may recover the decoded
signal again and remove the decoded signal from the received
signals. Here, the DL terminal may determine whether it is possible
to decode the signal having the largest received power.
[0112] For example, the DL terminal may regard all the signals
except for the signal having the highest received power as noise.
Here, the DL terminal may determine whether it is possible to
decode the signal having the highest received power based on a
signal-to-interference and noise ratio (SINR) and a predetermined
threshold value.
[0113] The DL terminal may sort co-channel interference values due
to respective transmission signals of the plurality of UL terminals
according to their sizes in descending order. For example, the DL
terminal may determine whether or not it is possible to decode a
transmission signal that generates CCI of the i-th size based on
Equation 14 below.
| h U , i | 2 P U , i | h D | 2 P D + i = i + 1 N | h U , j | 2 P U
, j .gtoreq. .gamma. . [ Equation 14 ] ##EQU00005##
[0114] Here, .gamma. may indicate the predetermined threshold
value. N may indicate the total number of UL terminals that cause
interference to the DL terminal due to CCI. The P.sub.D may
indicate a transmission power of the base station. h.sub.D may
indicate a channel for transmitting a downlink signal to the DL
terminal. P.sub.U,i may indicate a transmission power of the UL
terminal generating the i-th strongest UL CCI with the DL terminal.
h.sub.U,i may indicate a channel through which a signal generating
the i-th strongest UL CCI passes.
[0115] The DL terminal may decode all the signals that generate the
first to (i-1)th strongest CCI when the interference cancellation
for the signal generating the i-th strongest CCI is possible.
Therefore, the DL terminal is able to perform interference
cancellation on all signals that generate the first to (i-1)th CCI.
Also, the DL terminal may previously store or estimate channel
information for a transmission signal of a UL terminal that
generates CCI which can be cancelled.
[0116] FIG. 7 is a conceptual diagram illustrating exemplary
positions of a base station and a plurality of terminals located in
a cell.
[0117] Referring to FIG. 7, a base station 710 may simultaneously
perform clustering and scheduling based on position information
received from a plurality of terminals.
[0118] For example, the base station 710 may receive position
information of a first DL terminal 721 from the first DL terminal
721. The base station 710 may determine a first guard zone 731 that
is a circle centered on the position of the first DL terminal 721
based on the position information of the first DL terminal 721.
Also, the base station 710 may receive position information of a
second DL terminal 722 from the second DL terminal 722. The base
station 710 may determine a second guard zone 732 based on the
position of the second DL terminal 722 based on the position
information of the second DL terminal 722. Similarly, the base
station 710 may receive position information of third to seventh DL
terminals 723 to 727 from the third to seventh DL terminals 723
through 727. Similarly, the base station 710 may determine third to
seventh guard zones 733 to 737 based on the positions of the third
to seventh DL terminals 723 to 727.
[0119] The base station 710 may control interference cancellation
of the DL terminal according to whether at least one UL terminal is
located in a guard zone centered at the DL terminal. For example,
when a UL terminal is located in the guard zone centered on the DL
terminal, the base station 710 may determine that the size of the
CCI exceeds a predetermined threshold interference value.
Accordingly, when a UL terminal is located in the guard zone
centered on the DL terminal, the base station 710 may transmit a
message requesting interference cancellation to the DL terminal.
The diameter of the guard zone may be set differently depending on
a channel environment or other environment.
[0120] For example, the base station 710 may determine whether a UL
terminal is located within the guard zone based on the position
information of the DL terminal. The base station 710 may determine
a scheduling priority for the DL terminal according to whether a UL
terminal is located within the guard zone.
[0121] For example, the base station 710 may determine a scheduling
priority for the DL terminal according to the number of UL
terminals located in the guard zone of the DL terminal. For
example, the base station 710 may determine a scheduling priority
for a DL terminal in a guard zone in which UL terminals smaller
than a predetermined threshold number are located to be high. Also,
the base station 710 may determine a scheduling priority for a DL
terminal having a guard zone in which a UL terminal is not located
to be the lowest.
[0122] The base station 710 may determine a UL terminal to use a
same channel (i.e., to be paired) with a DL terminal having the
highest scheduling priority. That is, the base station 710 may pair
the DL terminal having the highest scheduling priority and the
determined UL terminal. The base station 710 may maximize the
number of DL terminals using the same channel with the UL terminal
in the guard zone by performing pairing on DL terminals and UL
terminals according to the scheduling priorities.
[0123] A plurality of UL terminals may be located in the guard zone
of the DL terminal having the highest scheduling priority. Here,
the base station 710 may determine the UL terminal to use the same
channel with the DL terminal, based on distances between the
plurality of UL terminals and the DL terminal. For example, the
base station 710 may determine a UL terminal located at a shortest
distance from the DL terminal among the plurality of UL terminals
as the UL terminal for using the same channel with the DL
terminal.
[0124] There may be a DL terminal having a guard zone where a UL
terminal is not located. Here, the base station 710 may determine a
scheduling priority for the DL terminal having a guard zone where a
UL terminal is not located according to a predetermined algorithm.
At this time, the base station 710 may schedule DL terminals and UL
terminals based on distances between each of the DL terminals and
each of the UL terminals and scheduling priorities of them. For
example, the base station 710 may determine scheduling orders for
DL terminals according to their scheduling priorities. Also, the
base station 710 may determine a UL terminal, which is located the
farthest distance from the DL terminal having the guard zone where
a UL terminal is not located, to be the UL terminal to use the same
channel with the DL terminal.
[0125] For example, the base station 710 may generate scheduling
information for the first to seventh DL terminals 721 to 727 and
the first to seventh UL terminals 741 to 747 based on the position
information of the terminals as shown in Tables 1 to 7 below.
[0126] Referring to Table 1 below, the base station 710 may
allocate a frequency-time resource for each of the first to seventh
DL terminals 741 to 747. For example, the base station 710 may
allocate a first timeslot (t=1) to the first DL terminal (D1) 721.
The base station 710 may allocate a second timeslot (t=2) to the
second DL terminal (D2) 722. The base station 710 may allocate a
third timeslot (t=3) to the third DL terminal (D3) 723. The base
station 710 may allocate a fourth time slot (t=4) to the fourth DL
terminal (D4) 724. The base station 710 may allocate a fifth time
slot (t=5) to the fifth DL terminal (D5) 725. The base station 710
may allocate a sixth timeslot (t=6) to the sixth DL terminal (D6)
726. The base station 710 may allocate a seventh time slot (t=7) to
the seventh DL terminal (D7) 727.
[0127] The base station 710 may determine UL terminals located on
each of the first to seventh guard zones 731 to 737 based on the
position information of the first to seventh UL terminals and the
first to seventh DL terminals. For example, when a UL terminal is
located in each guard zone, the base station 710 may indicate it
with `1` as shown in Table 1. Also, if a UL terminal is not located
in each guard zone, the base station 710 may indicate it with `0`
as shown in Table 1.
[0128] For example, the base station 710 may determine that a UL
terminal is not located in the first guard zone 731. The base
station 710 may determine that the first UL terminal (U1) 741 is
located in the second guard zone 732. That is, the base station 710
may determine that one UL terminal (U1) 741 is located in the
second guard zone 732. The base station 710 may determine that the
second UL terminal (U2) 742 and the sixth uplink terminal (U6) 746
are located in the third guard zone 733. That is, the base station
710 may determine that two UL terminals 742 and 746 are located in
the third guard zone 733. The base station 710 may determine that a
UL terminal is not located in the fourth guard zone 734. The base
station 710 may determine that the seventh UL terminal (U7) 747 is
located in the fifth guard zone 735. That is, the base station 710
may determine that one UL terminal 747 is located in the fifth
guard zone 735. The base station 710 may determine that the second
UL terminal (U2) 742 and the fourth UL terminal (U4) 744 are
located in the sixth guard zone 736. That is, the base station 710
may determine that two UL terminals 742 and 744 are located in the
sixth guard zone 736. The base station 710 may determine that the
third UL terminal (U3) 743 is located in the seventh guard zone
737. That is, the base station 710 may determine that one UL
terminal (U3) 743 is located in the seventh guard zone 737.
[0129] Here, the base station 710 may assign a first priority to
the fifth DL terminal 725 based on the user pairing algorithm. The
base station 710 may determine the seventh UL terminal 747 located
in the guard zone 735 of the fifth DL terminal 725 as the UL
terminal to be paired with the fifth DL terminal 725. The base
station 710 may complete resource allocation and pairing for the
fifth DL terminal 725 and the seventh UL terminal 747.
TABLE-US-00001 TABLE 1 # of UL UEs Pri- Scheduled U1 U2 U3 U4 U5 U6
U7 in GZ ority UL UE t = 1 D1 0 0 0 0 0 0 0 0 5 t = 2 D2 1 0 0 0 0
0 0 1 6 t = 3 D3 0 1 0 0 0 1 0 2 3 t = 4 D4 0 0 0 0 0 0 0 0 7 t = 5
D5 0 0 0 0 0 0 1 1 1 U7 t = 6 D6 0 1 0 1 0 0 0 2 4 t = 7 D7 0 0 1 0
0 0 0 1 2
[0130] Referring to Table 2 below, when the resource allocation and
pairing for the seventh UL terminal 747 and the fifth DL terminal
725 are completed, the base station 710 may perform scheduling for
terminals except the seventh UL terminal 747 and the fifth DL
terminal 725 paired with the seventh UL terminal 747.
[0131] The base station 710 may then assign a first priority to the
seventh DL terminal 727 based on the user pairing algorithm. The
base station 710 may determine the third UL terminal 743 located in
the seventh guard zone 737 as the UL terminal to be paired with the
seventh DL terminal 727. The base station 710 may complete resource
allocation and pairing for the seventh DL terminal 727 and the
third UL terminal 743.
TABLE-US-00002 TABLE 2 # of UL UEs Pri- Scheduled U1 U2 U3 U4 U5 U6
U7 in GZ ority UL UE t = 1 D1 0 0 0 0 0 0 -- 0 5 t = 2 D2 1 0 0 0 0
0 -- 1 2 t = 3 D3 0 1 0 0 0 1 -- 2 3 t = 4 D4 0 0 0 0 0 0 -- 0 6 t
= 5 D5 -- -- -- -- -- -- -- -- -- t = 6 D6 0 1 0 1 0 0 -- 2 4 t = 7
D7 0 0 1 0 0 0 -- 1 1 U3
[0132] Referring to Table 3 below, when the resource allocation and
pairing for the third UL terminal 743 and the seventh DL terminal
727 are completed, the base station 710 may perform scheduling for
terminals except for the third UL terminal 743 and the seventh DL
terminal 727 paired with the third UL terminal 743.
[0133] The base station 710 may then assign a first priority to the
second DL terminal 722 based on the user pairing algorithm. The
base station 710 may determine the first UL terminal 741 located in
the second guard zone 732 as the UL terminal to be paired with the
second DL terminal 722. The base station 710 may complete resource
allocation and pairing for the second DL terminal 722 and the first
UL terminal 741.
TABLE-US-00003 TABLE 3 # of UL UEs Pri- Scheduled U1 U2 U3 U4 U5 U6
U7 in GZ ority UL UE t = 1 D1 0 0 -- 0 0 0 -- 0 4 t = 2 D2 1 0 -- 0
0 0 -- 1 1 U1 t = 3 D3 0 1 -- 0 0 1 -- 2 2 t = 4 D4 0 0 -- 0 0 0 --
0 5 t = 5 D5 -- -- -- -- -- -- -- -- -- t = 6 D6 0 1 -- 1 0 0 -- 2
3 t = 7 D7 -- -- -- -- -- -- -- -- --
[0134] Referring to Table 4 below, when the resource allocation and
pairing for the first UL terminal 741 and the second DL terminal
722 are completed, the base station 710 may perform scheduling for
terminals except for the first UL terminal 741 and the second DL
terminal 722 paired with the first UL terminal 741.
[0135] The base station 710 may then assign a first priority to the
third DL terminal 723 based on the user pairing algorithm. The base
station 710 may determine a UL terminal to be paired with the third
DL terminal 723 based on the position information of the second UL
terminal 742 and the sixth UL terminal 746 located in the third
guard zone 733.
[0136] For example, the base station 710 may determine a UL
terminal located at a closer distance from the third DL terminal
723 among the second UL terminal 742 and the sixth UL terminal 746
as a UL terminal to be paired with the third DL terminal 723. For
example, the distance between the third DL terminal 723 and the
sixth UL terminal 746 is shorter than the distance between the
third DL terminal 723 and the second UL terminal 742.
[0137] Thus, the sixth UL terminal 746 may be determined as the UL
terminal to be paired with the third DL terminal 723. The base
station 710 may complete resource allocation and pairing for the
third DL terminal 723 and the sixth UL terminal 746.
TABLE-US-00004 TABLE 4 # of UL UEs Pri- Scheduled U1 U2 U3 U4 U5 U6
U7 in GZ ority UL UE t = 1 D1 -- 0 -- 0 0 0 -- 0 3 t = 2 D2 -- --
-- -- -- -- -- -- -- t = 3 D3 -- 1 -- 0 0 1 -- 2 1 U6 t = 4 D4 -- 0
-- 0 0 0 -- 0 4 t = 5 D5 -- -- -- -- -- -- -- -- -- t = 6 D6 -- 1
-- 1 0 0 -- 2 2 t = 7 D7 -- -- -- -- -- -- -- -- --
[0138] Referring to Table 5 below, when the resource allocation and
pairing for the sixth UL terminal 746 are completed, the base
station 710 may perform scheduling for terminals except for the
sixth UL terminal 746 and the third DL terminal 723 paired with the
sixth UL terminal 746.
[0139] The base station 710 may then assign a first priority to the
sixth DL terminal 726 based on the user pairing algorithm. The base
station 710 may determine a UL terminal to be paired with the sixth
DL terminal 726 based on the position information of the second UL
terminal 742 and the fourth UL terminal 744 located in the sixth
guard zone 736.
[0140] For example, the base station 710 may determine a UL
terminal located at a closer distance from the sixth DL terminal
726 among the second UL terminal 742 and the fourth UL terminal 744
as a UL terminal to be paired with the sixth DL terminal 726. For
example, the distance between the third DL terminal 723 and the
fourth UL terminal 744 is shorter than the distance between the
third DL terminal 723 and the second UL terminal 742.
[0141] Thus, the fourth UL terminal 744 may be determined as the UL
terminal to be paired with the sixth DL terminal 726. The base
station 710 may complete resource allocation and pairing for the
sixth DL terminal 726 and the fourth UL terminal 744.
TABLE-US-00005 TABLE 5 # of UL UEs Pri- Scheduled U1 U2 U3 U4 U5 U6
U7 in GZ ority UL UE t = 1 D1 -- 0 -- 0 0 -- -- 0 2 t = 2 D2 -- --
-- -- -- -- -- -- -- t = 3 D3 -- -- -- -- -- -- -- -- -- t = 4 D4
-- 0 -- 0 0 -- -- 0 3 t = 5 D5 -- -- -- -- -- -- -- -- -- t = 6 D6
-- 1 -- 1 0 -- -- 2 1 U4 t = 7 D7 -- -- -- -- -- -- -- -- --
[0142] Referring to Table 6 below, when the resource allocation and
pairing for the fourth UL terminal 744 and the sixth DL terminal
726 are completed, the base station 710 may perform scheduling for
terminals except for the fourth UL terminal 744 and the sixth DL
terminal 726 paired with the fourth UL terminal 744.
[0143] The base station 710 may assign a first priority to the
first DL terminal 721 based on the user pairing algorithm. The base
station 710 may determine a UL terminal to be paired with the first
DL terminal 721 based on the position information of the second UL
terminal 742 and the fifth UL terminal 745 which are not yet
scheduled.
[0144] For example, the base station 710 may determine a UL
terminal located at a farther distance from the first DL terminal
721 among the second UL terminal 742 and the fifth UL terminal 745
as a UL terminal to be paired with the first DL terminal 721. For
example, the distance between the first DL terminal 721 and the
fifth UL terminal 745 is farther than the distance between the
first DL terminal 721 and the second UL terminal 742.
[0145] Thus, the fifth UL terminal 745 may be determined as the UL
terminal to be paired with the first DL terminal 721. The base
station 710 may complete resource allocation and pairing for the
fifth DL terminal 721 and the fifth UL terminal 745.
[0146] The base station 710 may assign a second priority to the
fourth DL terminal 724 based on the user pairing algorithm. The
base station 710 may determine the second UL terminal which is not
scheduled as a UL terminal to be paired with the fourth DL terminal
724. The base station 710 may complete resource allocation and
pairing for the fourth DL terminal 724 and the second UL terminal
742.
TABLE-US-00006 TABLE 6 # of UL UEs Pri- Scheduled U1 U2 U3 U4 U5 U6
U7 in GZ ority UL UE t = 1 D1 -- 0 -- -- 0 -- -- 0 1 U5 t = 2 D2 --
-- -- -- -- -- -- -- -- t = 3 D3 -- -- -- -- -- -- -- -- -- t = 4
D4 -- 0 -- -- 0 -- -- 0 2 U2 t = 5 D5 -- -- -- -- -- -- -- -- -- t
= 6 D6 -- -- -- -- -- -- -- -- -- t = 7 D7 -- -- -- -- -- -- -- --
--
[0147] As shown in Table 7 below, the base station 710 may complete
the resource allocation and pairing for the first to seventh DL
terminals 721 to 727 and the first to seventh UL terminals 741 to
747.
TABLE-US-00007 TABLE 7 Time slot DL terminal UL terminal t = 1 D1
U5 t = 2 D2 U1 t = 3 D3 U6 t = 4 D4 U2 t = 5 D5 U7 t = 6 D6 U4 t =
7 D7 U3
[0148] Then, the base station 710 may generate scheduling
information including resource allocation information, pairing
information, and interference control information for the first to
seventh DL terminals 721 to 727 and the first to seventh UL
terminals 741 to 747.
[0149] The resource allocation information may include information
on frequency-time resources allocated to the first to seventh DL
terminals 721 to 727 and the first to seventh UL terminals 741 to
747, respectively. For example, the resource allocation information
may include information on the time slot allocated to each of the
DL and UL terminals. The base station 710 may transmit the resource
allocation information to the first to seventh DL terminals 721 to
727 and the first to seventh UL terminals 741 to 747,
respectively.
[0150] The pairing information may include information on UL
terminals using the same frequency-time resource for each of the
first to seventh DL terminals 721 to 727. For example, the pairing
information may include identification information for a UL
terminal using the same channel for each of the first to seventh DL
terminals 721 to 727. The base station 710 may transmit the pairing
information to each of the first to seventh DL terminals 721 to
727.
[0151] The interference control information may include a value
indicating whether the DL terminal should perform an interference
cancellation operation. For example, the interference control
information may include a value of `0` or `1`. In this case, the
value of `0` may indicate that the interference cancellation
operation is not instructed, and the value of `1` may indicate that
the interference cancellation operation is instructed.
[0152] The base station 710 may determine a DL terminal required to
perform the interference cancellation operation based on the user
pairing algorithm. For example, the base station 710 may determine
that the interference cancellation is required for a DL terminal
paired with a UL terminal located in a guard zone. That is, the
base station 710 may determine that the interference cancellation
operation is required for the DL terminal using the same channel
with the UL terminal located at a close distance. For example, the
base station 710 may determine that the second DL terminal 722, the
third DL terminal 723, and the fifth to seventh DL terminals 725 to
727, which are paired with a UL terminal located in each guard
zone, are required to perform the interference cancellation
operation.
[0153] Accordingly, the base station 710 may transmit the
interference control information including the value of `1`
instructing to perform the interference cancellation operation to
the second DL terminal 722, the third DL terminal 723, and the
fifth to seventh DL terminals 725 to 727. The base station 710 may
receive, from each of the second DL terminal 722, the third DL
terminal 723, and the fifth to seventh DL terminals 725 to 727, a
response message indicating that the resource allocation
information, pairing information, and interference control
information have been received.
[0154] After receiving the response message, the base station 710
may transmit a data signal to each of the second DL terminal 722,
the third DL terminal 723, and the fifth to seventh DL terminals
725 to 727. Each of the second DL terminal 722, the third DL
terminal 723, and the fifth to seventh DL terminals 725 to 727 may
receive the data signal from the base station 710. Each of the
second DL terminal 722, the third DL terminal 723, and the fifth to
seventh DL terminals 725 to 727 may perform the SCCIC operation on
the received data signal according to the interference control
information for each.
[0155] On the other hand, the base station 710 may determine that
the interference cancellation operation is not required for the DL
terminal paired with the UL terminal that is not located in the
guard zone. That is, the base station 710 may determine that the
interference cancellation operation is unnecessary for the DL
terminal using the same frequency-time resource with the UL
terminal located at a far distance. For example, the base station
710 may determine that the first DL terminal 721 and the fourth DL
terminal 724 using the same frequency-time resource with the UL
terminal located at a far distance are not required to perform the
interference cancellation operation.
[0156] Accordingly, the base station 710 may transmit interference
control information including the value of `0` instructing not to
perform the interference cancellation operation to the first DL
terminal 721 and the fourth DL terminal 724. The base station 710
may receive a response indicating that each of the terminals has
received the scheduling information including the resource
allocation information, the pairing information, and the
interference control information from each of the first DL terminal
721 and the fourth DL terminal 724.
[0157] After receiving the response message, the base station 710
may transmit a data signal to each of the first DL terminal 721 and
the fourth DL terminal 724. Each of the first DL terminal 721 and
the fourth DL terminal 724 may receive the data signal from the
base station 710. At this time, each of the first DL terminal 721
and the fourth DL terminal 724 may receive the data signal without
interference cancellation according to the interference control
information.
[0158] FIG. 8 is a graph for comparing downlink performances of
different operating modes including an operating mode based on
scheduling and interference control proposed by the present
disclosure.
[0159] Referring to FIG. 8, average DL capacities (bps/Hz) for four
different operating modes 804 to 807 are shown. The average DL
capacities may vary according to guard zone ratios and SCCIC
thresholds (dB). Also, the average DL capacities 804 to 807 may
vary depending on the operating mode of the base station.
[0160] The guard zone ratio may mean a ratio to a predetermined
radius R of the guard zone. The SCCIC threshold value may mean a
reference value for the DL terminal to perform the SCCIC operation.
For example, if a received signal strength exceeds the SCCIC
threshold, the DL terminal may perform the SCCIC operation on the
received signal.
[0161] For example, referring to the average DL capacity of the IFD
operating mode (i.e., the IFD scheme) 804, the DL performance of a
base station operating in the IFD operating mode may be the lowest.
Also, referring to the average downlink capacity of the HD
operating mode (i.e., the HD scheme) 805, the DL performance of a
base station operating in the HD operating mode may be superior to
the DL performance of the base station operating in the IFD scheme.
On the other hand, referring to the average DL capacity of the
operating mode 806 based on IFD scheme with SCCIC, the DL
performance of a base station operating in the scheme of IFD with
SCCIC may be superior to the DL performance of the base station
operating in the HD scheme.
[0162] Also, referring to the average DL capacity of the operating
mode 807 based on IFD scheme with existing scheduling and proposed
scheduling, the DL performance of a base station operating in the
operating mode based on IFD scheme with existing scheduling and
proposed scheduling may be superior to the DL performance of the
base station operating in the operating mode based on IFD scheme
with SCCIC. Here, the existing scheduling may mean the IFD scheme
with SCCIC.
[0163] The UL performances of the above-described four operating
modes may be the same. Therefore, the scheduling scheme proposed by
the present disclosure can improve the performance of the entire
communication network.
[0164] FIG. 9 is a graph for comparing downlink performance
increments of different operating modes including an operating mode
based on scheduling and interference control proposed by the
present disclosure.
[0165] Referring to FIG. 9, average DL capacity increments over
time-division duplexing (TDD) (%) for three different operating
modes 904 to 906 are shown. Each of the average DL capacity
increments over TDD may be an increment from the average DL
capacity in the HD operating mode.
[0166] The average DL capacity increments may vary according to
guard zone ratios and SCCIC thresholds (dB). Also, the average DL
capacity increments may vary depending on the operating mode of the
base station.
[0167] For example, referring to the average DL capacity increment
904 of the IFD operating mode (i.e., the IFD scheme), DL
performance of a base station operating in the IFD scheme may be
reduced. On the other hand, referring to the average DL capacity
increment 905 of the operating mode based on the IFD scheme with
SCCIC, the DL performance of a base station operating in the
operating mode based on the IFD scheme with SCCIC may be improved
as compared to that of the HD operating mode.
[0168] Also, referring to the average DL capacity increment 906 of
the operating mode based on the IFD scheme with existing scheduling
and proposed scheduling, the DL performance of a base station
operating in the operating mode based on the IFD scheme with
existing scheduling and proposed scheduling may be further
increased as compared to the DL performance of the base station
operating in the operating mode based on the IFD scheme with SCCIC.
Here, the existing scheduling may mean the IFD scheme with
SCCIC.
[0169] The UL performances of the above-described four operating
modes may be the same. Therefore, the scheduling scheme proposed by
the present disclosure can improve the performance of the entire
communication network.
[0170] Also, the DL performance of the base station in the
scheduling scheme proposed by the present disclosure can be
improved so as to achieve a DL performance gain up to 60% as
compared to the HD operating mode's DL capacity by optimizing the
guard zone ratio and the SCCIC threshold.
[0171] The embodiments of the present disclosure may be implemented
as program instructions executable by a variety of computers and
recorded on a computer readable medium. The computer readable
medium may include a program instruction, a data file, a data
structure, or a combination thereof. The program instructions
recorded on the computer readable medium may be designed and
configured specifically for the present disclosure or can be
publicly known and available to those who are skilled in the field
of computer software. Examples of the computer readable medium may
include a hardware device such as
[0172] ROM, RAM, and flash memory, which are specifically
configured to store and execute the program instructions. Examples
of the program instructions include machine codes made by, for
example, a compiler, as well as high-level language codes
executable by a computer, using an interpreter. The above exemplary
hardware device can be configured to operate as at least one
software module in order to perform the embodiments of the present
disclosure, and vice versa.
[0173] While the embodiments of the present disclosure and their
advantages have been described in detail, it should be understood
that various changes, substitutions and alterations may be made
herein without departing from the scope of the present
disclosure.
* * * * *