U.S. patent application number 17/014318 was filed with the patent office on 2021-04-08 for method and apparatus for transmitting and receiving data in communication system.
The applicant listed for this patent is ELECTRONICS AND TELECOMMUNICATIONS RESEARCH INSTITUTE. Invention is credited to Jae Heung KIM.
Application Number | 20210105851 17/014318 |
Document ID | / |
Family ID | 1000005079903 |
Filed Date | 2021-04-08 |
United States Patent
Application |
20210105851 |
Kind Code |
A1 |
KIM; Jae Heung |
April 8, 2021 |
METHOD AND APPARATUS FOR TRANSMITTING AND RECEIVING DATA IN
COMMUNICATION SYSTEM
Abstract
An operation method of a base station in a communication system
may include generating an indicator indicating transmission of
small data; transmitting the indicator to a terminal; and
transmitting the small data associated with the indicator to the
terminal, wherein the terminal operates in a radio resource control
(RRC) idle state or an RRC inactive state.
Inventors: |
KIM; Jae Heung; (Sejong-si,
KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ELECTRONICS AND TELECOMMUNICATIONS RESEARCH INSTITUTE |
Daejeon |
|
KR |
|
|
Family ID: |
1000005079903 |
Appl. No.: |
17/014318 |
Filed: |
September 8, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W 68/02 20130101;
H04W 76/27 20180201; H04L 1/1812 20130101; H04W 74/0833 20130101;
H04W 72/042 20130101 |
International
Class: |
H04W 76/27 20060101
H04W076/27; H04W 72/04 20060101 H04W072/04; H04W 74/08 20060101
H04W074/08; H04L 1/18 20060101 H04L001/18; H04W 68/02 20060101
H04W068/02 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 2, 2019 |
KR |
10-2019-0122649 |
Oct 24, 2019 |
KR |
10-2019-0133247 |
Nov 25, 2019 |
KR |
10-2019-0152726 |
Aug 21, 2020 |
KR |
10-2020-0105282 |
Claims
1. An operation method of a base station in a communication system,
the operation method comprising: generating an indicator indicating
transmission of small data; transmitting the indicator to a
terminal; and transmitting the small data associated with the
indicator to the terminal, wherein the terminal operates in a radio
resource control (RRC) idle state or an RRC inactive state.
2. The operation method according to claim 1, wherein the indicator
is included in downlink control information (DCI) transmitted from
the base station to the terminal.
3. The operation method according to claim 2, wherein a cyclic
redundancy check (CRC) of the DCI including the indicator is
scrambled with a paging-radio network temporary identifier (P-RNTI)
or a small-RNTI (SM-RNTI) configured for transmission of the small
data.
4. The operation method according to claim 2, wherein the DCI
further includes resource allocation information of the small
data.
5. The operation method according to claim 1, wherein a
transmission window starts at a time of transmitting the indicator,
and the small data is transmitted within the transmission
window.
6. The operation method according to claim 1, further comprising
receiving a hybrid automatic repeat request (HARQ) response for the
small data from the terminal, wherein the HARQ response is received
in a random access (RA) procedure.
7. The operation method according to claim 6, wherein the HARQ
response is a RA preamble, and a first RA preamble corresponding to
acknowledgement (ACK) is configured to be different from a second
RA preamble corresponding to negative ACK (NACK).
8. The operation method according to claim 1, wherein the small
data is transmitted to the terminal on a paging channel (PCH) or a
downlink-shared channel (DL-SCH).
9. The operation method according to claim 1, wherein a
transmission resource of the small data is configured within a
bandwidth part (BWP) configured by the base station, and
configuration information of the BWP is transmitted from the base
station to the terminal.
10. An operation method of a terminal in a communication system,
the operation method comprising: receiving downlink control
information (DCI) from a base station by performing a monitoring
operation in a physical downlink control channel (PDCCH) monitoring
occasion; determining that small data to be transmitted to the
terminal exists in the base station based on an indicator included
in the DCI; and receiving the small data associated with the
indicator from the base station, wherein the terminal operates in a
radio resource control (RRC) idle state or an RRC inactive
state.
11. The operation method according to claim 10, wherein the
monitoring operation is performed using a paging-radio network
temporary identifier (P-RNTI) or a small-RNTI (SM-RNTI) configured
for transmission of the small data.
12. The operation method according to claim 10, wherein the PDCCH
monitoring occasion is configured by the base station, and the DCI
obtained from the PDCCH monitoring operation further includes
resource allocation information of the small data.
13. The operation method according to claim 10, wherein a reception
window starts at a time of receiving the indicator, a size of the
reception window is configured by the base station, and a reception
operation of the small data is not performed after the reception
window ends.
14. The operation method according to claim 10, further comprising
transmitting a hybrid automatic repeat request (HARQ) response for
the small data to the base station in a random access (RA)
procedure.
15. The operation method according to claim 14, wherein the HARQ
response is a RA preamble, a first RA preamble corresponding to
acknowledgement (ACK) is configured to be different from a second
RA preamble corresponding to negative ACK (NACK), and configuration
information of the first RA preamble and the second RA preamble is
received from the base station.
16. A terminal in a communication system, the terminal comprising:
a processor; a memory electronically communicating with the
processor; and instructions stored in the memory, wherein when
executed by the processor, the instructions cause the terminal to:
receive configuration information for a transmission and reception
operation of small data from a base station; receive downlink
control information (DCI) from the base station by performing a
monitoring operation in a physical downlink control channel (PDCCH)
monitoring occasion indicated by the configuration information;
determine that small data to be transmitted to the terminal exists
in the base station based on an indicator included in the DCI; and
receive the small data associated with the indicator from the base
station, wherein the terminal operates in a radio resource control
(RRC) idle state or an RRC inactive state.
17. The terminal according to claim 16, wherein the configuration
information includes a paging-radio network temporary identifier
(P-RNTI) or a small-RNTI (SM-RNTI) configured for transmission of
the small data, and the monitoring operation is performed using the
P-RNTI or the SM-RNTI.
18. The terminal according to claim 16, wherein the configuration
information includes configuration information of a reception
window, the reception window starts at a time of receiving the
indicator, and the small data is received within the reception
window.
19. The terminal according to claim 16, wherein the configuration
information includes configuration information of a pre-allocated
downlink resource (PDR), and the small data is received in the
PDR.
20. The terminal according to claim 16, wherein the instructions
further cause the terminal to transmit a hybrid automatic repeat
request (HARD) response for the small data to the base station in a
random access (RA) procedure.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to Korean Patent
Applications No. 10-2019-0122649 filed on Oct. 2, 2019, No.
10-2019-0133247 filed on Oct. 24, 2019, No. 10-2019-0152726 filed
on Nov. 25, 2019, and No. 10-2020-0105282 filed on Aug. 21, 2020
with 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 technique for
transmitting and receiving data in a communication system, and more
specifically, to a technique for transmitting and receiving data
occurring intermittently (e.g., data having a small size).
2. Description of Related Art
[0003] With the development of information and communication
technology, various wireless communication technologies have been
developed. Typical wireless communication technologies include long
term evolution (LTE) and new radio (NR), which are defined in the
3rd generation partnership project (3GPP) standards. The LTE may be
one of 4th generation (4G) wireless communication technologies, and
the NR may be one of 5th generation (5G) wireless communication
technologies.
[0004] The communication system (hereinafter, a new radio (NR)
communication system) using a higher frequency band (e.g., a
frequency band of 6 GHz or above) than a frequency band (e.g., a
frequency band of 6 GHz or below) of the long term evolution (LTE)
(or, LTE-A) is being considered for processing of soaring wireless
data. The 5G communication system can support enhanced mobile
broadband (eMBB), ultra-reliable low-latency communication (URLLC),
massive machine type communication (mMTC), and the like.
[0005] Meanwhile, a millimeter frequency band (e.g., a frequency
band of 6 to 90 GHz) may be used to process rapidly increasing
data. A small base station may be used to overcome deterioration of
received signal performance due to path attenuation and reflection
of radio waves in a high frequency band (e.g., millimeter frequency
band). In a communication system supporting the millimeter
frequency band, instead of a small base station supporting all
functions of a radio protocol, a plurality of remote radio
transmission/reception blocks (e.g., remote radio heads (RRHs)) and
a centralized baseband processing function block may be
deployed.
[0006] That is, all functions of a radio protocol can be
distributedly supported in the remote radio transmission/reception
blocks and the baseband processing function block in a functional
split scheme. When the functional split technique is used, the
communication system may be configured by a plurality of
transmission and reception points (TRPs). The plurality of TRPs may
perform communications using a carrier aggregation scheme, a dual
connectivity scheme, a duplication transmission scheme, or the
like. In the communication system supporting the functional split
scheme, the carrier aggregation scheme, the dual connectivity
scheme, a bi-casting scheme, the duplication transmission scheme,
or the like, methods for transmitting and receiving data occurring
intermittently (e.g., data having a small size) are required.
SUMMARY
[0007] Accordingly, exemplary embodiments of the present disclosure
are directed to providing methods and apparatuses for transmitting
and receiving data in a communication system.
[0008] According to a first exemplary embodiment of the present
disclosure, an operation method of a base station in a
communication system may comprise generating an indicator
indicating transmission of small data; transmitting the indicator
to a terminal; and transmitting the small data associated with the
indicator to the terminal, wherein the terminal operates in a radio
resource control (RRC) idle state or an RRC inactive state.
[0009] The indicator may be included in downlink control
information (DCI) transmitted from the base station to the
terminal.
[0010] A cyclic redundancy check (CRC) of the DCI including the
indicator may be scrambled with a paging-radio network temporary
identifier (P-RNTI) or a small-RNTI (SM-RNTI) configured for
transmission of the small data.
[0011] The DCI may further include resource allocation information
of the small data.
[0012] A transmission window may start at a time of transmitting
the indicator, and the small data may be transmitted within the
transmission window.
[0013] The operation method may further comprise receiving a hybrid
automatic repeat request (HARQ) response for the small data from
the terminal, wherein the HARQ response is received in a random
access (RA) procedure.
[0014] The HARQ response may be a RA preamble, and a first RA
preamble corresponding to acknowledgement (ACK) may be configured
to be different from a second RA preamble corresponding to negative
ACK (NACK).
[0015] The small data may be transmitted to the terminal on a
paging channel (PCH) or a downlink-shared channel (DL-SCH).
[0016] A transmission resource of the small data may be configured
within a bandwidth part (BWP) configured by the base station, and
configuration information of the BWP may be transmitted from the
base station to the terminal.
[0017] According to a second exemplary embodiment of the present
disclosure, an operation method of a terminal in a communication
system may comprise receiving downlink control information (DCI)
from a base station by performing a monitoring operation in a
physical downlink control channel (PDCCH) monitoring occasion;
determining that small data to be transmitted to the terminal
exists in the base station based on an indicator included in the
DCI; and receiving the small data associated with the indicator
from the base station, wherein the terminal operates in a radio
resource control (RRC) idle state or an RRC inactive state.
[0018] The monitoring operation may be performed using a
paging-radio network temporary identifier (P-RNTI) or a small-RNTI
(SM-RNTI) configured for transmission of the small data.
[0019] The PDCCH monitoring occasion may be configured by the base
station, and the DCI obtained from the PDCCH monitoring operation
may further include resource allocation information of the small
data.
[0020] A reception window may start at a time of receiving the
indicator, a size of the reception window may be configured by the
base station, and a reception operation of the small data may not
be performed after the reception window ends.
[0021] The operation method may further comprise transmitting a
hybrid automatic repeat request (HARQ) response for the small data
to the base station in a random access (RA) procedure.
[0022] The HARQ response may be a RA preamble, a first RA preamble
corresponding to acknowledgement (ACK) may be configured to be
different from a second RA preamble corresponding to negative ACK
(NACK), and configuration information of the first RA preamble and
the second RA preamble may be received from the base station.
[0023] According to a third exemplary embodiment of the present
disclosure, a terminal in a communication system may comprise a
processor; a memory electronically communicating with the
processor; and instructions stored in the memory, wherein when
executed by the processor, the instructions cause the terminal to
receive configuration information for a transmission and reception
operation of small data from a base station; receive downlink
control information (DCI) from the base station by performing a
monitoring operation in a physical downlink control channel (PDCCH)
monitoring occasion indicated by the configuration information;
determine that small data to be transmitted to the terminal exists
in the base station based on an indicator included in the DCI; and
receive the small data associated with the indicator from the base
station, wherein the terminal operates in a radio resource control
(RRC) idle state or an RRC inactive state.
[0024] The configuration information may include a paging-radio
network temporary identifier (P-RNTI) or a small-RNTI (SM-RNTI)
configured for transmission of the small data, and the monitoring
operation may be performed using the P-RNTI or the SM-RNTI.
[0025] The configuration information may include configuration
information of a reception window, the reception window may start
at a time of receiving the indicator, and the small data may be
received within the reception window.
[0026] The configuration information may include configuration
information of a pre-allocated downlink resource (PDR), and the
small data may be received in the PDR.
[0027] The instructions may further cause the terminal to transmit
a hybrid automatic repeat request (HARD) response for the small
data to the base station in a random access (RA) procedure.
[0028] According to exemplary embodiments of the present
disclosure, the base station can transmit an indicator informing
that a small packet exists to the terminal, and can transmit the
small packet associated with indicator to the terminal. The
terminal operating in a radio resource control (RRC) inactive state
or an RRC idle state may receive the indicator from the base
station, and may determine that the small packet to be transmitted
to the terminal exists in the base station based on the indicator.
The terminal operating in the RRC inactive state or the RRC idle
state may receive the small packet from the base station without
transition of the operation state. Accordingly, the small packet
transmission/reception procedure can be quickly performed, and
accordingly, performance of the communication system can be
improved.
BRIEF DESCRIPTION OF DRAWINGS
[0029] Exemplary 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:
[0030] FIG. 1 is a conceptual diagram illustrating a first
exemplary embodiment of a communication system;
[0031] FIG. 2 is a block diagram illustrating a first embodiment of
a communication node constituting a communication system;
[0032] FIG. 3 is a conceptual diagram illustrating a second
exemplary embodiment of a communication system;
[0033] FIG. 4 is a conceptual diagram illustrating a first
exemplary embodiment of a method for configuring bandwidth parts
(BWPs) in a communication system;
[0034] FIG. 5 is a conceptual diagram illustrating a first
exemplary embodiment of operation states of a terminal in a
communication system;
[0035] FIG. 6 is a sequence chart illustrating a first exemplary
embodiment of a random access procedure in a communication
system;
[0036] FIG. 7 is a sequence chart illustrating a second exemplary
embodiment of a random access procedure in a communication system;
and
[0037] FIG. 8 is a timing diagram illustrating a first exemplary
embodiment of a method of transmitting and receiving a small packet
in a communication system.
[0038] It should be understood that the above-referenced drawings
are not necessarily to scale, presenting a somewhat simplified
representation of various preferred features illustrative of the
basic principles of the disclosure. The specific design features of
the present disclosure, including, for example, specific
dimensions, orientations, locations, and shapes, will be determined
in part by the particular intended application and use
environment.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0039] 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. Thus, 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.
[0040] Accordingly, while the present disclosure is capable of
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.
[0041] 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.
[0042] 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.).
[0043] 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.
[0044] 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.
[0045] Hereinafter, exemplary 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.
[0046] A communication system to which exemplary embodiments
according to the present disclosure are applied will be described.
The communication system to which the exemplary embodiments
according to the present disclosure are applied is not limited to
the contents described below, and the exemplary embodiments
according to the present disclosure may be applied to various
communication networks. Here, the communication system may be used
in the same sense as a communication network.
[0047] FIG. 1 is a conceptual diagram illustrating a first
exemplary embodiment of a communication system.
[0048] 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. The plurality
of communication nodes may support 4th generation (4G)
communication (e.g., long term evolution (LTE), LTE-advanced
(LTE-A)), 5th generation (5G) communication (e.g., new radio (NR)),
or the like. The 4G communication may be performed in a frequency
band of 6 gigahertz (GHz) or below, and the 5G communication may be
performed in a frequency band of 6 GHz or above.
[0049] For example, for the 4G and 5G communications, the plurality
of communication nodes may support 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, a
filtered OFDM based communication protocol, a cyclic prefix OFDM
(CP-OFDM) based communication protocol, a discrete Fourier
transform spread OFDM (DFT-s-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, a generalized frequency division
multiplexing (GFDM) based communication protocol, a filter bank
multi-carrier (FBMC) based communication protocol, a universal
filtered multi-carrier (UFMC) based communication protocol, a space
division multiple access (SDMA) based communication protocol, or
the like.
[0050] Also, the communication system 100 may further include a
core network. When the communication system 100 supports the 4G
communication, the core network may comprise a serving gateway
(S-GW), a packet data network (PDN) gateway (P-GW), a mobility
management entity (MME), and the like. When the communication
system 100 supports the 5G communication, the core network may
comprise a user plane function (UPF), a session management function
(SMF), an access and mobility management function (AMF), and the
like.
[0051] Meanwhile, each of the 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 constituting the communication system 100 may have
the following structure.
[0052] FIG. 2 is a block diagram illustrating a first embodiment of
a communication node constituting a communication system.
[0053] 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.
[0054] However, each component included in the communication node
200 may be connected to the processor 210 via an individual
interface or a separate bus, rather than the common bus 270. For
example, the processor 210 may be connected to at least one of the
memory 220, the transceiver 230, the input interface device 240,
the output interface device 250, and the storage device 260 via a
dedicated interface.
[0055] 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).
[0056] Referring again to FIG. 1, the communication system 100 may
comprise a plurality of base stations 110-1, 110-2, 110-3, 120-1,
and 120-2, and a plurality of terminals 130-1, 130-2, 130-3, 130-4,
130-5, and 130-6. The communication system 100 including the base
stations 110-1, 110-2, 110-3, 120-1, and 120-2 and the terminals
130-1, 130-2, 130-3, 130-4, 130-5, and 130-6 may be referred to as
an `access network`. Each of the first base station 110-1, the
second base station 110-2, and the third base station 110-3 may
form a macro cell, and each of the fourth base station 120-1 and
the fifth base station 120-2 may form a small cell. The fourth base
station 120-1, the third terminal 130-3, and the fourth terminal
130-4 may belong to cell coverage of the first base station 110-1.
Also, the second terminal 130-2, the fourth terminal 130-4, and the
fifth terminal 130-5 may belong to cell coverage of the second base
station 110-2. Also, the fifth base station 120-2, the fourth
terminal 130-4, the fifth terminal 130-5, and the sixth terminal
130-6 may belong to cell coverage of the third base station 110-3.
Also, the first terminal 130-1 may belong to cell coverage of the
fourth base station 120-1, and the sixth terminal 130-6 may belong
to cell coverage of the fifth base station 120-2.
[0057] Here, each of the plurality of base stations 110-1, 110-2,
110-3, 120-1, and 120-2 may refer to a Node-B, a evolved Node-B
(eNB), a base transceiver station (BTS), a radio base station, a
radio transceiver, an access point, an access node, a road side
unit (RSU), a radio remote head (RRH), a transmission point (TP), a
transmission and reception point (TRP), an eNB, a gNB, or the
like.
[0058] Here, each of the plurality of terminals 130-1, 130-2,
130-3, 130-4, 130-5, and 130-6 may refer to a user equipment (UE),
a terminal, an access terminal, a mobile terminal, a station, a
subscriber station, a mobile station, a portable subscriber
station, a node, a device, an Internet of things (IoT) device, a
mounted apparatus (e.g., a mounted module/device/terminal or an
on-board device/terminal, etc.), or the like.
[0059] Meanwhile, each of the plurality of base stations 110-1,
110-2, 110-3, 120-1, and 120-2 may operate in the same frequency
band or in different frequency bands. The plurality of base
stations 110-1, 110-2, 110-3, 120-1, and 120-2 may be connected to
each other via an ideal backhaul or a non-ideal backhaul, and
exchange information with each other via the ideal or non-ideal
backhaul. Also, each of the plurality of base stations 110-1,
110-2, 110-3, 120-1, and 120-2 may be connected to the core network
through the ideal or non-ideal backhaul. Each of the plurality of
base stations 110-1, 110-2, 110-3, 120-1, and 120-2 may transmit a
signal received from the core network to the corresponding terminal
130-1, 130-2, 130-3, 130-4, 130-5, or 130-6, and transmit a signal
received from the corresponding terminal 130-1, 130-2, 130-3,
130-4, 130-5, or 130-6 to the core network.
[0060] Also, each of the plurality of base stations 110-1, 110-2,
110-3, 120-1, and 120-2 may support multi-input multi-output (MIMO)
transmission (e.g., a single-user MIMO (SU-MIMO), multi-user MIMO
(MU-MIMO), massive MIMO, or the like), coordinated multipoint
(CoMP) transmission, carrier aggregation (CA) transmission,
transmission in an unlicensed band, device-to-device (D2D)
communications (or, proximity services (ProSe)), or the like. Here,
each of the plurality of terminals 130-1, 130-2, 130-3, 130-4,
130-5, and 130-6 may perform operations corresponding to the
operations of the plurality of base stations 110-1, 110-2, 110-3,
120-1, and 120-2, and operations supported by the plurality of base
stations 110-1, 110-2, 110-3, 120-1, and 120-2. For example, the
second base station 110-2 may transmit a signal to the fourth
terminal 130-4 in the SU-MIMO manner, and the fourth terminal 130-4
may receive the signal from the second base station 110-2 in the
SU-MIMO manner. Alternatively, the second base station 110-2 may
transmit a signal to the fourth terminal 130-4 and fifth terminal
130-5 in the MU-MIMO manner, and the fourth terminal 130-4 and
fifth terminal 130-5 may receive the signal from the second base
station 110-2 in the MU-MIMO manner.
[0061] The first base station 110-1, the second base station 110-2,
and the third base station 110-3 may transmit a signal to the
fourth terminal 130-4 in the CoMP transmission manner, and the
fourth terminal 130-4 may receive the signal from the first base
station 110-1, the second base station 110-2, and the third base
station 110-3 in the CoMP manner. Also, each of the plurality of
base stations 110-1, 110-2, 110-3, 120-1, and 120-2 may exchange
signals with the corresponding terminals 130-1, 130-2, 130-3,
130-4, 130-5, or 130-6 which belongs to its cell coverage in the CA
manner. Each of the base stations 110-1, 110-2, and 110-3 may
control D2D communications between the fourth terminal 130-4 and
the fifth terminal 130-5, and thus the fourth terminal 130-4 and
the fifth terminal 130-5 may perform the D2D communications under
control of the second base station 110-2 and the third base station
110-3.
[0062] Hereinafter, methods for transmitting and receiving data in
a communication system will be described. Even when a method (e.g.,
transmission or reception of a data packet) performed at a first
communication node among communication nodes is described, the
corresponding second communication node may perform a method (e.g.,
reception or transmission of the data packet) corresponding to the
method performed at the first communication node. That is, when an
operation of a terminal is described, the corresponding base
station may perform an operation corresponding to the operation of
the terminal. Conversely, when an operation of the base station is
described, the corresponding terminal may perform an operation
corresponding to the operation of the base station.
[0063] In the following exemplary embodiments, a signaling message
may be a signaling message including system information, an RRC
signaling message, a MAC signaling message (e.g., MAC control
element (CE)), and/or a PHY signaling message (e.g., downlink
control information (DCI), uplink control information (UCI),
sidelink control information (SCI)). The signaling message may be
referred to as a `control message`. In this case, the control
message may be a control message including system information, an
RRC control message, a MAC control message, and/or a PHY control
message.
[0064] Meanwhile, in a communication system, a base station may
perform all functions (e.g., remote radio transmission and
reception function, baseband processing function, and the like) of
a communication protocol. Alternatively, the remote radio
transmission and reception function among all the functions of the
communication protocol may be performed by a transmission reception
point (TRP) (e.g., flexible TRP (f-TRP)), and the baseband
processing function among all the functions of the communication
protocol may be performed by a baseband unit (BBU) block. The TRP
may be a remote radio head (RRH), a radio unit (RU), a transmission
point (TP), or the like. The BBU block may include at least one BBU
or at least one digital unit (DU). The BBU block may be referred to
as a `BBU pool`, a `centralized BBU`, or the like. The TRP may be
connected to the BBU block via a wired fronthaul link or a wireless
fronthaul link. A communication system composed of a backhaul link
and a fronthaul link may be as follows. When a functional-split
technique of the communication protocol is applied, the TRP may
selectively perform some functions of the BBU or some functions of
a medium access control (MAC) layer or a radio link control (RLC)
layer.
[0065] FIG. 3 is a conceptual diagram illustrating a second
exemplary embodiment of a communication system.
[0066] Referring to FIG. 3, a communication system may include a
core network and an access network. The core network supporting the
4G communication may include an MME, an S-GW, a P-GW, and the like.
The core network supporting the 5G communication may include an AMF
310-1, an UPF 310-2, a PDN-GW 310-3, and the like. The access
network may include a macro base station 320, a small base station
330, TRPs 350-1 and 350-2, terminals 360-1, 360-2, 360-3, 360-4,
and 360-5, and the like. The macro base station 320 or the small
base station 330 may be connected to a termination node of the core
network via a wired backhaul. The TRPs 350-1 and 350-2 may support
the remote radio transmission and reception function among all the
functions of the communication protocol, and the baseband
processing function for the TRPs 350-1 and 350-2 may be performed
by the BBU block 340. The BBU block 340 may belong to the access
network or the core network. The communication nodes (e.g., MME,
S-GW, P-GW, AMF, UPF, PDN-GW, macro base station, small base
station, TRPs, terminals, and BBU block) belonging to the
communication system may be configured identically or similarly to
the communication node 200 shown in FIG. 2.
[0067] The macro base station 320 may be connected to the core
network (e.g., AMF 310-1, UPF 310-2, MME, S-GW) using a wired
backhaul link or a wireless backhaul link, and may provide
communication services to the terminals 360-3 and 360-4 based on a
communication protocol (e.g., 4G communication protocol, 5G
communication protocol). The small base station 330 may be
connected to the core network (e.g., AMF 310-1, UPF 310-2, MME,
S-GW) using a wired backhaul link or a wireless backhaul link, and
may provide communication services to the terminal 360-5 based on a
communication protocol (e.g., 4G communication protocol, 5G
communication protocol).
[0068] The BBU block 340 may be located in the AMF 310-1, the UPF
310-2, the MME, the S-GW, or the macro base station 320.
Alternatively, the BBU block 340 may be located independently of
each the AMF 310-1, the UPF 310-2, the MME, the S-GW, and the macro
base station 320. For example, the BBU block 340 may be configured
as a logical function block between the macro base station 320 and
the AMF 310-1 (or UPF 310-2). The BBU block 340 may support the
plurality of TRPs 350-1 and 350-2, and may be connected to each of
the plurality of TRPs 350-1 and 350-2 using a wired fronthaul link
or a wireless fronthaul link. That is, the link between the BBU
block 340 and the TRPs 350-1 and 350-2 may be referred to as a
`fronthaul link`.
[0069] The first TRP 350-1 may be connected to the BBU block 340
via a wired fronthaul link or a wireless fronthaul link, and
provide communication services to the first terminal 360-1 based on
a communication protocol (e.g., 4G communication protocol, 5G
communication protocol). The second TRP 350-2 may be connected to
the BBU block 340 via a wired fronthaul link or a wireless
fronthaul link, and provide communication services to the second
terminal 360-2 based on a communication protocol (e.g., 4G
communication protocol, 5G communication protocol).
[0070] The communication system including the access network, the
Xhaul network, and the core network may be referred to as an
`integrated communication system`. The communication nodes (e.g.,
MME, S-GW, P-GW, AMF, UPF, BBU block, distributed unit (DU),
central unit (CU), base station, TRP, terminal, and the like)
belonging to the integrated communication system may be configured
identically or similarly to the communication node 200 shown in
FIG. 2. The communication nodes belonging to the Xhaul network may
be connected using Xhaul links, and the Xhaul link may be a
backhaul link or a fronthaul link.
[0071] Also, the UPF (or, S-GW) of the integrated communication
system may refer to a termination communication node of the core
network that exchanges packets (e.g., control information, data)
with the base station, and the AMF (or, MME) of the integrated
communication system may refer to a communication node in the core
network, which performs control functions in a radio access section
(or, interface) of the terminal. Here, each of the backhaul link,
fronthaul link, Xhaul link, DU, CU, BBU block, S-GW, MME, AMF, and
UPF may be referred to as a different term according to a function
(e.g., function of the Xhaul network, function of the core network)
of a communication protocol depending on a radio access technology
(RAT).
[0072] In order to perform a mobility support function and a radio
resource management function, the base station may transmit a
synchronization signal (e.g., a synchronization signal/physical
broadcast channel (SS/PBCH) block) and/or a reference signal. In
order to support multiple numerologies, frame formats supporting
symbols having different lengths may be configured. In this case,
the terminal may perform a monitoring operation on the
synchronization signal and/or reference signal in a frame according
to an initial numerology, a default numerology, or a default symbol
length. Each of the initial numerology and the default numerology
may be applied to a frame format applied to radio resources in
which a UE-common search space is configured, a frame format
applied to radio resources in which a control resource set
(CORESET) #0 of the NR communication system is configured, and/or a
frame format applied to radio resources in which a synchronization
symbol burst capable of identifying a cell in the NR communication
system is transmitted.
[0073] The frame format may refer to information of configuration
parameters (e.g., values of the configuration parameters, offset,
index, identifier, range, periodicity, interval, duration, etc.)
for a subcarrier spacing, control channel (e.g., CORESET), symbol,
slot, and/or reference signal. The base station may inform the
frame format to the terminal using system information and/or a
control message (e.g., dedicated control message).
[0074] The terminal connected to the base station may transmit a
reference signal (e.g., uplink dedicated reference signal) to the
base station using resources configured by the corresponding base
station. For example, the uplink dedicated reference signal may
include a sounding reference signal (SRS). In addition, the
terminal connected to the base station may receive a reference
signal (e.g., downlink dedicated reference signal) from the base
station in resources configured by the corresponding base station.
The downlink dedicated reference signal may be a channel state
information-reference signal (CSI-RS), a phase tracking-reference
signal (PT-RS), a demodulation-reference signal (DM-RS), or the
like. Each of the base station and the terminal may perform a beam
management operation through monitoring on a configured beam or an
active beam based on the reference signal.
[0075] For example, the first base station 611 may transmit a
synchronization signal and/or a reference signal so that the first
terminal 621 located within its service area can search for itself
to perform downlink synchronization maintenance, beam
configuration, or link monitoring operations. The first terminal
621 connected to the first base station 611 (e.g., serving base
station) may receive physical layer radio resource configuration
information for connection configuration and radio resource
management from the first base station 611. The physical layer
radio resource configuration information may mean configuration
parameters included in RRC control messages of the LTE
communication system or the NR communication system. For example,
the resource configuration information may include
PhysicalConfigDedicated, PhysicalCellGroupConfig,
PDCCH-Config(Common), PDSCH-Config(Common), PDCCH-ConfigSIB1,
ConfigCommon, PUCCH-Config(Common), PUSCH-Config(Common),
BWP-DownlinkCommon, BWP-UplinkCommon, ControlResourceSet,
RACH-ConfigCommon, RACH-ConfigDedicated, RadioResourceConfigCommon,
RadioResourceConfigDedicated, ServingCellConfig,
ServingCellConfigCommon, and the like.
[0076] The radio resource configuration information may include
parameter values such as a configuration (or allocation)
periodicity of a signal (or radio resource) according to a frame
format of the base station (or transmission frequency), time
resource allocation information for transmission, frequency
resource allocation information for transmission, a transmission
(or allocation) time, or the like. In order to support multiple
numerologies, the frame format of the base station (or transmission
frequency) may mean a frame format having different symbol lengths
according to a plurality of subcarrier spacings within one radio
frame. For example, the number of symbols constituting each of a
mini-slot, slot, and subframe that exist within one radio frame
(e.g., a frame of 10 ms) may be configured differently. [0077]
Configuration information of transmission frequency and frame
format of base station [0078] Transmission frequency configuration
information: information on all transmission carriers (i.e.,
cell-specific transmission frequency) in the base station,
information on bandwidth parts (BWPs) in the base station,
information on a transmission reference time or time difference
between transmission frequencies of the base station (e.g., a
transmission periodicity or offset parameter indicating the
transmission reference time (or time difference) of the
synchronization signal), etc. [0079] Frame format configuration
information: configuration parameters of a mini-slot, slot, and
subframe having a different symbol length according to a subcarrier
spacing [0080] Configuration information of downlink reference
signal (e.g., channel state information-reference signal (CSI-RS),
common reference signal (Common-RS), etc.) [0081] Configuration
parameters such as a transmission periodicity, transmission
position, code sequence, or masking (or scrambling) sequence for a
reference signal, which are commonly applied within the coverage of
the base station (or beam). [0082] Configuration information of
uplink control signal [0083] Configuration parameters such as a
sounding reference signal (SRS), uplink beam sweeping (or beam
monitoring) reference signal, uplink grant-free radio resources
(or, preambles), etc. [0084] Configuration information of physical
downlink control channel (e.g., PDCCH) [0085] Configuration
parameters such as a reference signal for PDCCH demodulation, beam
common reference signal (e.g., reference signal that can be
received by all terminals within a beam coverage), beam sweeping
(or beam monitoring) reference signal, reference signal for channel
estimation, etc. [0086] Configuration information of physical
uplink control channel (e.g., PUCCH) [0087] Scheduling request
signal configuration information [0088] Configuration information
for a feedback (acknowledgement (ACK) or negative ACK (NACK))
transmission resource in a hybrid automatic repeat request (HARD)
procedure [0089] Number of antenna ports, antenna array
information, beam configuration or beam index mapping information
for application of beamforming techniques [0090] Configuration
information of downlink signal and/or uplink signals (or uplink
access channel resource) for beam sweeping (or beam monitoring)
[0091] Configuration information of parameters for beam
configuration, beam recovery, beam reconfiguration, or radio link
re-establishment operation, beam change operation within the same
base station, reception signal of a beam triggering handover
execution to another base station, timers controlling the
above-described operations, etc.
[0092] In case of a radio frame format that supports a plurality of
symbol lengths for supporting multi-numerology, the configuration
(or allocation) periodicity of the parameter, the time resource
allocation information, the frequency resource allocation
information, the transmission time, and/or the allocation time,
which constitute the above-described information, may be
information configured for each corresponding symbol length (or
subcarrier spacing).
[0093] In the following exemplary embodiments, `Resource-Config
information` may be a control message including one or more
parameters of the physical layer radio resource configuration
information. In addition, the `Resource-Config information` may
mean attributes and/or configuration values (or range) of
information elements (or parameters) delivered by the control
message. The information elements (or parameters) delivered by the
control message may be radio resource configuration information
applied commonly to the entire coverage of the base station (or,
beam) or radio resource configuration information allocated
dedicatedly to a specific terminal (or, specific terminal group). A
terminal group may include one or more terminals.
[0094] The configuration information included in the
`Resource-Config information` may be transmitted through one
control message or different control messages according to the
attributes of the configuration information. The beam index
information may not express the index of the transmission beam and
the index of the reception beam explicitly. For example, the beam
index information may be expressed using a reference signal mapped
or associated with the corresponding beam index or an index (or
identifier) of a transmission configuration indicator (TCI) state
for beam management.
[0095] Therefore, the terminal operating in the RRC connected state
may receive a communication service through a beam (e.g., beam
pair) configured between the terminal and the base station. For
example, when a communication service is provided using beam
configuration (e.g., beam pairing) between the base station and the
terminal, the terminal may perform a search operation or a
monitoring operation of a radio channel by using a synchronization
signal (e.g., SS/PBCH block) and/or a reference signal (e.g.,
CSI-RS) of a beam configured with the base station, or a beam the
can be received. Here, the expression that a communication service
is provided through a beam may mean that a packet is transmitted
and received through an active beam among one or more configured
beams. In the NR communication system, the expression that a beam
is activated may mean that a configured TCI state is activated.
[0096] The terminal may operate in the RRC idle state or the RRC
inactive state. In this case, the terminal may perform a search
operation (e.g., monitoring operation) of a downlink channel by
using parameter(s) obtained from system information or common
Resource-Config information. In addition, the terminal operating in
the RRC idle state or the RRC inactive state may attempt to access
by using an uplink channel (e.g., a random access channel or a
physical layer uplink control channel). Alternatively, the terminal
may transmit control information by using an uplink channel.
[0097] The terminal may recognize or detect a radio link problem by
performing a radio link monitoring (RLM) operation. Here, the
expression that a radio link problem is detected may mean that
physical layer synchronization configuration or maintenance for a
radio link has a problem. For example, the expression that a radio
link problem is detected may mean that it is detected that the
physical layer synchronization between the base station and the
terminal is not maintained during a preconfigured time. When a
radio link problem is detected, the terminal may perform a recovery
operation of the radio link. When the radio link is not recovered,
the terminal may declare a radio link failure (RLF) and perform a
re-establishment procedure of the radio link.
[0098] The procedure for detecting a physical layer problem of a
radio link, procedure for recovering a radio link, procedure for
detecting (or declaring) a radio link failure, and procedure for
re-establishing a radio link according to the RLM operation may be
performed by functions of a layer 1 (e.g., physical layer), a layer
2 (e.g., MAC layer, RLC layer, PDCP layer, etc.), and/or a layer 3
(e.g., RRC layer) of the radio protocol.
[0099] The physical layer of the terminal may monitor a radio link
by receiving a downlink synchronization signal (e.g., primary
synchronization signal (PSS), secondary synchronization signal
(SSS), SS/PBCH block) and/or a reference signal. In this case, the
reference signal may be a base station common reference signal,
beam common reference signal, or terminal (or terminal group)
specific reference signal (e.g., dedicated reference signal
allocated to a terminal (or terminal group)). Here, the common
reference signal may be used for channel estimation operations of
all terminals located within the corresponding base station or beam
coverage (or service area). The dedicated reference signal may be
used for a channel estimation operation of a specific terminal or a
specific terminal group located within the base station or beam
coverage.
[0100] Accordingly, when the base station or the beam (e.g.,
configured beam between the base station and the terminal) is
changed, the dedicated reference signal for beam management may be
changed. The beam may be changed based on the configuration
parameter(s) between the base station and the terminal. A procedure
for changing the configured beam may be required. The expression
that a beam is changed in the NR communication system may mean that
an index (or identifier) of a TCI state is changed to an index of
another TCI state, that a TCI state is newly configured, or that a
TCI state is changed to an active state. The base station may
transmit system information including configuration information of
the common reference signal to the terminal. The terminal may
obtain the common reference signal based on the system information.
In a handover procedure, synchronization reconfiguration procedure,
or connection reconfiguration procedure, the base station may
transmit a dedicated control message including the configuration
information of the common reference signal to the terminal.
[0101] The configured beam information may include at least one of
a configured beam index (or identifier), configured TCI state index
(or identifier), configuration information of each beam (e.g.,
transmission power, beam width, vertical angle, horizontal angle),
transmission and/or reception timing information of each beam
(e.g., subframe index, slot index, mini-slot index, symbol index,
offset), reference signal information corresponding to each beam,
and reference signal identifier.
[0102] In the exemplary embodiments, the base station may be a base
station installed in the air. For example, the base station may be
installed on an unmanned aerial vehicle (e.g., drone), a manned
aircraft, or a satellite.
[0103] The terminal may receive configuration information of the
base station (e.g., identification information of the base station)
from the base station through one or more of an RRC message, MAC
message, and PHY message, and may identify a base station with
which the terminal performs a beam monitoring operation, radio
access operation, and/or control (or data) packet transmission and
reception operation.
[0104] The result of the measurement operation (e.g., beam
monitoring operation) for the beam may be reported through a
physical layer control channel (e.g., PUCCH) and/or a MAC message
(e.g., MAC CE, control PDU). Here, the result of the beam
monitoring operation may be a measurement result for one or more
beams (or beam groups). For example, the result of the beam
monitoring operation may be a measurement result for beams (or beam
groups) according to a beam sweeping operation of the base
station.
[0105] The base station may obtain the result of the beam
measurement operation or the beam monitoring operation from the
terminal, and may change the properties of the beam or the
properties of the TCI state based on the result of the beam
measurement operation or the beam monitoring operation. The beam
may be classified into a primary beam, a secondary beam, a reserved
(or candidate) beam, an active beam, and a deactivated beam
according to its properties. The TCI state may be classified into a
primary TCI state, a secondary TCI state, a reserved (or candidate)
TCI state, a serving TCI state, a configured TCI state, an active
TCI state, and a deactivated TCI state according to its properties.
Each of the primary TCI state and the secondary TCI state may be
assumed to be an active TCI state and a serving TCI state. The
reserved (or candidate) TCI state may be assumed to be a
deactivated TCI state or a configured TCI state.
[0106] A procedure for changing the beam (or TCI state) property
may be controlled by the RRC layer and/or the MAC layer. When the
procedure for changing the beam (or TCI state) property is
controlled by the MAC layer, the MAC layer may inform the higher
layer of information regarding a change in the beam (or TCI state)
property. The information regarding the change in the beam (or TCI
state) property may be transmitted to the terminal through a MAC
message and/or a physical layer control channel (e.g., PDCCH). The
information regarding the change in the beam (or TCI state)
property may be included in downlink control information (DCI) or
uplink control information (UCI). The information regarding the
change in the beam (or TCI state) property may be expressed as a
separate indicator or field.
[0107] The terminal may request to change the property of the TCI
state based on the result of the beam measurement operation or the
beam monitoring operation. The terminal may transmit control
information (or feedback information) requesting to change the
property of the TCI state to the base station by using one or more
of a PHY message, a MAC message, and an RRC message. The control
information (or feedback information, control message, control
channel) requesting to change the property of the TCI state may be
configured using one or more of the configured beam information
described above.
[0108] The change in the property of the beam (or TCI state) may
mean a change from the active beam to the deactivated beam, a
change from the deactivated beam to the active beam, a change from
the primary beam to the secondary beam, a change from the secondary
beam to the primary beam, a change from the primary beam to the
reserved (or candidate) beam, or a change from the reserved (or
candidate) beam to the primary beam. The procedure for changing the
property of the beam (or TCI state) may be controlled by the RRC
layer and/or the MAC layer. The procedure for changing the property
of the beam (or TCI state) may be performed through partial
cooperation between the RRC layer and the MAC layer.
[0109] When a plurality of beams are allocated, one or more beams
among the plurality of beams may be configured as beam(s) for
transmitting physical layer control channels. For example, the
primary beam and/or the secondary beam may be used for transmission
and reception of a physical layer control channel (e.g., PHY
message). Here, the physical layer control channel may be a PDCCH
or a PUCCH. The physical layer control channel may be used for
transmission of one or more among scheduling information (e.g.,
radio resource allocation information, modulation and coding scheme
(MCS) information), feedback information (e.g., channel quality
indication (CQI), precoding matrix indicator (PMI), HARQ ACK, HARQ
NACK), resource request information (e.g., scheduling request
(SR)), result of the beam monitoring operation for supporting
beamforming functions, TCI state ID, and measurement information
for the active beam (or deactivated beam).
[0110] The physical layer control channel may be configured to be
transmitted through the primary beam of downlink. In this case, the
feedback information may be transmitted and received through the
primary beam, and data scheduled by the control information may be
transmitted and received through the secondary beam. The physical
layer control channel may be configured to be transmitted through
the primary beam of uplink. In this case, the resource request
information (e.g., SR) and/or the feedback information may be
transmitted and received through the primary beam.
[0111] In the procedure of allocating the plurality of beams (or
the procedure of configuring the TCI states), the allocated (or
configured) beam indexes, information indicating a spacing between
the beams, and/or information indicating whether contiguous beams
are allocated may be transmitted and received through a signaling
procedure between the base station and the terminal. The signaling
procedure of the beam allocation information may be performed
differently according to status information (e.g., movement speed,
movement direction, location information) of the terminal and/or
the quality of the radio channel. The base station may obtain the
status information of the terminal from the terminal.
Alternatively, the base station may obtain the status information
of the terminal through another method.
[0112] The radio resource information may include parameter(s)
indicating frequency domain resources (e.g., center frequency,
system bandwidth, PRB index, number of PRBs, CRB index, number of
CRBs, subcarrier index, frequency offset, etc.) and parameter(s)
indicating time domain resources (e.g., radio frame index, subframe
index, transmission time interval (TTI), slot index, mini-slot
index, symbol index, time offset, and periodicity, length, or
window of transmission period (or reception period)). In addition,
the radio resource information may further include a hopping
pattern of radio resources, information for beamforming (e.g., beam
shaping) operations (e.g., beam configuration information, beam
index), and information on resources occupied according to
characteristics of a code sequence (or bit sequence, signal
sequence).
[0113] The name of the physical layer channel and/or the name of
the transport channel may vary according to the type (or attribute)
of data, the type (or attribute) of control information, a
transmission direction (e.g., uplink, downlink, sidelink), and the
like.
[0114] The reference signal for beam (or TCI state) or radio link
management may be a synchronization signal (e.g., PSS, SSS, SS/PBCH
block), CSI-RS, PT-RS, SRS, DM-RS, or the like. The reference
parameter(s) for reception quality of the reference signal for beam
(or TCI state) or radio link management may include a measurement
time unit, a measurement time interval, a reference value
indicating an improvement in reception quality, a reference value
indicating a deterioration in reception quality, or the like. Each
of the measurement time unit and the measurement time interval may
be configured in units of an absolute time (e.g., millisecond,
second), TTI, symbol, slot, frame, subframe, scheduling
periodicity, operation periodicity of the base station, or
operation periodicity of the terminal.
[0115] The reference value indicating the change in reception
quality may be configured as an absolute value (dBm) or a relative
value (dB). In addition, the reception quality of the reference
signal for beam (or TCI state) or radio link management may be
expressed as a reference signal received power (RSRP), a reference
signal received quality (RSRQ), a received signal strength
indicator (RSSI), a signal-to-noise ratio (SNR), a
signal-to-interference ratio (SIR), or the like.
[0116] Meanwhile, in the NR communication system using a millimeter
frequency band, flexibility for a channel bandwidth operation for
packet transmission may be secured based on a bandwidth part (BWP)
concept. The base station may configure up to 4 BWPs having
different bandwidths to the terminal. The BWPs may be independently
configured for downlink and uplink. That is, downlink BWPs may be
distinguished from uplink BWPs. Each of the BWPs may have a
different subcarrier spacing as well as a different bandwidth. For
example, BWPs may be configured as follows.
[0117] FIG. 4 is a conceptual diagram illustrating a first
exemplary embodiment of a method for configuring bandwidth parts
(BWPs) in a communication system.
[0118] As shown in FIG. 4, a plurality of bandwidth parts (e.g.,
BWPs #1 to #4) may be configured within a system bandwidth of the
base station. The BWPs #1 to #4 may be configured not to be larger
than the system bandwidth of the base station. The bandwidths of
the BWPs #1 to #4 may be different, and different subcarrier
spacings may be applied to the BWPs #1 to #4. For example, the
bandwidth of the BWP #1 may be 10 MHz, and the BWP #1 may have a 15
kHz subcarrier spacing. The bandwidth of the BWP #2 may be 40 MHz,
and the BWP #2 may have a 15 kHz subcarrier spacing. The bandwidth
of the BWP #3 may be 10 MHz, and the BWP #3 may have a 30 kHz
subcarrier spacing. The bandwidth of the BWP #4 may be 20 MHz, and
the BWP #4 may have a 60 kHz subcarrier spacing.
[0119] The BWPs may be classified into an initial BWP (e.g., first
BWP), an active BWP (e.g., activated BWP), and a default BWP. The
terminal may perform an initial access procedure (e.g., access
procedure) with the base station in the initial BWP. One or more
BWPs may be configured through an RRC connection configuration
message, and one BWP among the one or more BWPs may be configured
as the active BWP. Each of the terminal and the base station may
transmit and receive packets in the active BWP among the configured
BWPs. Therefore, the terminal may perform a monitoring operation on
control channels for packet transmission and reception in the
active BWP.
[0120] The terminal may switch the operating BWP from the initial
BWP to the active BWP or the default BWP. Alternatively, the
terminal may switch the operating BWP from the active BWP to the
initial BWP or the default BWP. The BWP switching operation may be
performed based on an indication of the base station or a timer.
The base station may transmit information indicating the BWP
switching to the terminal using one or more of an RRC message, a
MAC message (e.g., MAC control element (CE)), and a PHY message
(e.g., DCI). The terminal may receive the information indicating
the BWP switching from the base station, and may switch the
operating BWP of the terminal to a BWP indicated by the received
information.
[0121] When a random access (RA) resource is not configured in the
active uplink (UL) BWP in the NR communication system, the terminal
may switch the operating BWP of the terminal from the active UL BWP
to the initial UL BWP in order to perform a random access
procedure. The operating BWP may be a BWP in which the terminal
performs communication (e.g., transmission and reception operation
of a signal and/or channel).
[0122] Measurement operations (e.g., monitoring operations) for
beam (or TCI state) or radio link management may be performed at
the base station and/or the terminal. The base station and/or the
terminal may perform the measurement operations (e.g., monitoring
operations) according to parameter(s) configured for the
measurement operations (e.g., monitoring operations). The terminal
may report a measurement result according to parameter(s)
configured for measurement reporting.
[0123] When a reception quality of a reference signal according to
the measurement result meets a preconfigured reference value and/or
a preconfigured timer condition, the base station may determine
whether to perform a beam (or, radio link) management operation, a
beam switching operation, or a beam deactivation (or, activation)
operation according to a beam blockage situation. When it is
determined to perform a specific operation, the base station may
transmit a message triggering execution of the specific operation
to the terminal. For example, the base station may transmit a
control message for instructing the terminal to execute the
specific operation to the terminal. The control message may include
configuration information of the specific operation.
[0124] When a reception quality of a reference signal according to
the measurement result meets a preconfigured reference value and/or
a preconfigured timer condition, the terminal may report the
measurement result to the base station. Alternatively, the terminal
may transmit to the base station a control message triggering a
beam (or, radio link) management operation, a beam switching
operation (or a TCI state ID change operation, a property change
operation), or a beam deactivation operation (or a beam activation
operation) according to a beam blockage situation. The control
message may request to perform a specific operation.
[0125] A basic procedure for beam (or TCI state) management through
the radio link monitoring may include a beam failure detection
(BFD) procedure, a beam recovery (BR) request procedure, and the
like for a radio link. An operation of determining whether to
perform the beam failure detection procedure and/or the beam
recovery request procedure, an operation triggering execution of
the beam failure detection procedure and/or the beam recovery
request procedure, and a control signaling operation for the beam
failure detection procedure and/or the beam recovery request
procedure may be performed by one or more of the PHY layer, the MAC
layer, and the RRC layer.
[0126] The procedure for the terminal to access the base station
(e.g., random access procedure) may be classified into an initial
access procedure and a non-initial access procedure. The terminal
operating in the RRC idle state may perform the initial access
procedure. Alternatively, when there is no context information
managed by the base station, the terminal operating in the RRC
connected state may also perform the initial access procedure. The
context information may include RRC context information, access
stratum (AS) configuration information (e.g., AS context
information), and the like. The context information may include one
or more among RRC configuration information for the terminal,
security configuration information for the terminal, PDCP
information including a robust header compression (ROHC) state for
the terminal, an identifier (e.g., cell-radio resource temporary
identifier (C-RNTI)) for the terminal, and an identifier of the
base station for which a connection configuration with the terminal
has been completed.
[0127] The non-initial access procedure may refer to an access
procedure performed by the terminal in addition to the initial
access procedure. For example, the non-initial access procedure may
be performed for an access request for transmission or reception
data arrival at the terminal, connection resumption, resource
allocation request, user (UE) request based information
transmission request, link re-establishment request after a radio
link failure (RLF), mobility function (e.g., handover function)
support, secondary cell addition/change, active beam
addition/change, or physical layer synchronization
configuration.
[0128] The random access procedure may be performed based on the
initial access procedure or the non-initial access procedure
according to the operation state of the terminal.
[0129] FIG. 5 is a conceptual diagram illustrating a first
exemplary embodiment of operation states of a terminal in a
communication system.
[0130] As shown in FIG. 5, operation states of the terminal may be
classified into an RRC connected state, an RRC inactive state, and
an RRC idle state. When the terminal operates in the RRC connected
state or the RRC inactive state, a radio access network (RAN)
(e.g., a control function block of the RAN) and the base station
may store and manage RRC connection configuration information
and/or context information (e.g., RRC context information, AS
context information) of the corresponding terminal.
[0131] The terminal operating in the RRC connected state may
receive configuration information of physical layer control
channels and/or reference signals required for maintaining
connection configuration and transmission/reception of data from
the base station. The reference signal may be a reference signal
for demodulating the data. Alternatively, the reference signal may
be a reference signal for channel quality measurement or
beamforming. Therefore, the terminal operating in the RRC connected
state may transmit and receive the data without delay.
[0132] When the terminal operates in the RRC inactive state,
mobility management functions/operations identical or similar to
mobility management functions/operations supported in the RRC idle
state may be supported for the corresponding terminal. That is,
when the terminal operates in the RRC inactive state, a data bearer
for transmitting and receiving data may not be configured, and
functions of the MAC layer may be deactivated. Accordingly, the
terminal operating in the RRC inactive state may transition the
operation state of the terminal from the RRC inactive state to the
RRC connected state by performing the non-initial access procedure
to transmit data. Alternatively, the terminal operating in the RRC
inactive state may transmit data having a limited size, data having
a limited quality of service, and/or data associated with a limited
service.
[0133] When the terminal operates in the RRC idle state, there may
be no connection configuration between the terminal and the base
station, and the RRC connection configuration information and/or
context information (e.g., RRC context information, AS context
information) of the terminal may not be stored in the RAN (e.g., a
control function block of the RAN) and the base station. In order
to transition the operation state of the terminal from the RRC idle
state to the RRC connected state, the terminal may perform the
initial access procedure. Alternatively, when the initial access
procedure is performed, the operation state of the terminal may
transition from the RRC idle state to the RRC inactive state
according to determination of the base station.
[0134] The terminal may transition from the RRC idle state to the
RRC inactive state by performing the initial access procedure or a
separate access procedure defined for the RRC inactive state. When
a limited service is provided to the terminal, the operation state
of the terminal may transition from the RRC idle state to the RRC
inactive state. Alternatively, depending on capability of the
terminal, the operation state of the terminal may transition from
the RRC idle state to the RRC inactive state.
[0135] The base station and/or the control function block of the
RAN may configure condition(s) for transitioning to the RRC
inactive state by considering one or more of the type, capability,
and service (e.g., a service currently being provided and a service
to be provided) of the terminal, and may control the operation for
transitioning to the RRC inactive state based on the configured
condition(s). When the base station allows the transition to the
RRC inactive state or when the transition to the RRC inactive state
is configured to be allowed, the operation state of the terminal
may be transitioned from the RRC connected state or the RRC idle
state to the RRC inactive state.
[0136] Data having a small size (hereinafter referred to as `small
data`) and/or a small size signaling message (hereinafter referred
to as `small signaling message`) may occur intermittently. Each of
the small data and the small signaling message may be referred to
as a `small packet (SM_Packet)`. When the small data and/or the
small signaling message is generated in the base station, the base
station may transmit the small data and/or the small signaling
message to the terminal operating in the RRC idle state or the RRC
inactive state. When the small data and/or the small signaling
message is generated in the terminal, the terminal (e.g., the
terminal operating in the RRC idle state or the RRC inactive state)
may transmit the small data and/or the small signaling message to
the base station. Here, the small data and/or the small signaling
message may be transmitted through a paging procedure or a random
access procedure.
[0137] FIG. 6 is a sequence chart illustrating a first exemplary
embodiment of a random access procedure in a communication
system.
[0138] Referring to FIG. 6, a communication system may include a
base station, a terminal, and the like. The base station may be the
base station 110-1, 110-2, 110-3, 120-1, or 120-2 shown in FIG. 1,
and the terminal may be the terminal 130-1, 130-2, 130-3, 130-4,
130-5, or 130-6 shown in FIG. 1. The base station and the terminal
may be configured to be the same or similar to the communication
node shown in FIG. 2. A random access procedure may be performed in
four steps.
[0139] The base station may transmit system information and/or a
control message including configuration information of a radio
resource (e.g., uplink radio resource) for the random access
procedure to the terminal (S601). The terminal may obtain the
configuration information of the radio resource for the random
access procedure by receiving the system information and/or control
message from the base station. The system information may be common
system information used for a plurality of base stations or base
station-specific system information (e.g., cell-specific system
information). The control message may be a dedicated control
message.
[0140] The system information may be configured for each base
station, for each beam group, or for each beam. The system
information may include allocation information of the radio
resource (e.g., uplink radio resource) for the random access
procedure. The configuration information of the radio resource for
the random access procedure may include one or more of transmission
frequency information of the physical layer, system bandwidth
information (or BWP configuration information), subcarrier spacing
information, beam configuration information according to a
beamforming technique (e.g., beam width, beam index), variable
radio resource configuration information (e.g., radio resource
reference value, offset) in the frequency and/or time domain, and
inactive (or unused) radio resource region/interval
information.
[0141] The terminal may transmit an RA message 1 (i.e., RA MSG1)
including an RA preamble to the base station using the radio
resource (e.g., physical random access channel (PRACH)) configured
by the base station (S602). The message 1 including the RA preamble
may be referred to as an `RA MSG1` in the 4-step random access
procedure, the RA preamble in the 4-step random access procedure
may be referred to as a `4-step-RA preamble`.
[0142] The terminal may randomly select a code sequence (e.g., RA
preamble, signature) defined for the random access procedure, and
transmit the RA MSG1 including the selected code sequence. In a
contention-based random access (CBRA) procedure, the terminal may
randomly select the RA preamble. In a contention-free random access
(CFRA) procedure, the base station may pre-allocate the RA preamble
to the terminal. The pre-allocation of the RA preamble may mean
that an index, masking information, etc. of the RA preamble for the
RA MSG1 is allocated dedicatedly to the terminal. In this case, the
terminal may perform the random access procedure (e.g., CFRA
procedure) without contention with other terminals.
[0143] The base station may receive the RA MSG1 from the terminal.
The base station may generate an RA MSG2 in response to the RA
MSG1, and may transmit the RA MSG2 to the terminal (S603). In the
4-step random access procedure, the RA MSG2 may mean a message 2, a
random access response (RAR), or an RAR message.
[0144] In the step S603, allocation information of an uplink radio
resource may be transmitted. Alternatively, the RA MSG2 may be
transmitted on a PDCCH or a physical downlink shared channel
(PDSCH). In the case that a DCI is transmitted in the step S603,
the corresponding DCI may include one or more among uplink resource
allocation information (e.g., scheduling information), transmission
timing adjustment information (e.g., a timing advance (TA) value, a
TA command), transmission power adjustment information, backoff
information, beam configuration information, TCI state information,
configured scheduling (CS) state information, state transition
information, PUCCH configuration information, an index of the RA
MSG1 received in the step S602 (e.g., an index of the RA preamble),
and uplink resource allocation information for transmission of an
RA MSG3 in a step S604.
[0145] Here, the beam configuration information may be information
indicating activation or deactivation of a specific beam. The TCI
state information may be information indicating activation or
deactivation of a specific TCI state. The CS state information or
configured grant (CG) state information may be information
indicating activation or deactivation of radio resources allocated
in the CS scheme. The state transition information may be
information indicating transition of the operation state of the
terminal shown in FIG. 5. The state transition information may
indicate transition from a specific operation state to the RRC idle
state, the RRC connected state, or the RRC inactive state.
Alternatively, the state transition information may indicate
maintaining of the current operation state. The PUCCH configuration
information may be allocation information of a scheduling request
(SR) resource. Alternatively, the PUCCH configuration information
may be information indicating activation or deactivation of an SR
resource.
[0146] The base station may transmit the DCI instead of the RA MSG2
in the step S603. In this case, control information may be
transmitted through a PDSCH. That is, the control information may
include one or more among uplink resource allocation information
(e.g., scheduling information), transmission timing adjustment
information (e.g., TA value, TA command), transmission power
adjustment information, backoff information, beam configuration
information, TCI state information, CS state information, state
transition information, PUCCH configuration information, the index
of the message 1 (e.g., RA preamble) received in the step S602, and
uplink resource allocation for transmission of an RA MSG3 in the
step S604.
[0147] The base station may transmit scheduling information of the
RA MSG2 to the terminal using a random access (RA)-RNTI. For
example, a cyclic redundancy check (CRC) of the DCI including the
scheduling information of the RA MSG2 may be scrambled by the
RA-RNTI, and the corresponding DCI may be transmitted through the
PDCCH. In addition, the base station may transmit the RA MSG2 using
a cell-RNTI (C-RNTI). The base station may transmit the RA MSG2 on
a PDSCH indicated by the scheduling information addressed by the
scheduling identifier (e.g., RA-RNTI, C-RNTI). The terminal may
receive the RA MSG2 from the base station. The terminal may
transmit an RA MSG3 (i.e., message 3) including its own information
to the base station (S604). The terminal information may include
one or more among the identifier of the terminal, capability,
property, mobility status, location information, a reason for the
radio access, size information of uplink data (e.g., buffer status
report (BSR)), connection configuration request information, and
uplink data. In addition, in the step S604, the terminal may
transmit information requesting information required by the
terminal to the base station.
[0148] When the RA MSG2 is received based on the DCI in the step
S603, the terminal may perform an operation according to the
information element(s) included in the PDCCH (or DCI). The
information element(s) included in the PDCCH (or DCI) may include
one or more among transition request information of the operation
state of the terminal, request information for maintaining the
operation state of the terminal, information indicating activation
or deactivation of a beam, information indicating activation or
deactivation of a TCI state, information indicating activation or
deactivation of a CS state. In this case, the random access
procedure may be terminated without performing the step S604.
[0149] If the RA MSG2 is received based on the DCI, and an uplink
radio resource for the RA MSG3 is not allocated in the step S603,
the terminal may wait until allocation information of the uplink
radio resource for the RA MSG3 is received. When the allocation
information of the uplink radio resource for the RA MSG3 is
received before a preconfigured timer expires, the terminal may
transmit the RA MSG3 to the base station using the uplink radio
resource. On the other hand, when the allocation information of the
uplink radio resource for the RA MSG3 is not received until the
preconfigured timer expires, the terminal may perform the random
access procedure again. That is, the terminal may perform again
from the step S602.
[0150] In a step S605, the base station may transmit downlink
information requested by the terminal. Alternatively, the base
station may transmit downlink data or a control message to the
terminal. In the step S605, the base station may transmit the
terminal identifier received from the terminal (e.g., the terminal
identifier received in the step S604) to the terminal. A message 4
transmitted by the base station in the step S605 may be referred to
as an `RA MSG4`.
[0151] The base station may transmit resource allocation
information (e.g., scheduling information) for transmission of the
RA MSG3 to the terminal using the RA MSG2. The scheduling
information may include one or more among the identifier of the
base station transmitting the scheduling information, beam index,
identifier for identifying the scheduling information, radio
resource allocation information, MCS information, and resource
allocation information for transmission of feedback information
(e.g., ACK or NACK) indicating whether the scheduling information
is received. The radio resource allocation information may include
frequency domain resource allocation information (e.g.,
transmission band information, subcarrier allocation information)
and/or time domain resource allocation information (e.g., frame
index, subframe index, slot index, symbol index, transmission
period, transmission timing).
[0152] In the random access procedure shown in FIG. 6, the RA MSG3
may include one or more of the following information elements.
[0153] Capability of the terminal [0154] Properties of the terminal
[0155] Mobility state of the terminal [0156] Location information
of the terminal [0157] Reason for attempting the access procedure
(e.g., random access procedure)
[0158] The reason for attempting the access procedure may be a
transmission request of system information according to a request
of the terminal, transmission request of downlink data according to
update of a firmware or essential software of the terminal, or
uplink resource allocation request. The information indicating the
reason for attempting the access procedure may be information
capable of distinguishing the reason for performing the access
procedure. The information capable of distinguishing the reason for
performing the access procedure may be as follows. [0159] Uplink
resource allocation information [0160] Handover request information
or measurement result information [0161] Terminal operation state
transition (or, change) request information [0162] Resumption
information of a radio channel [0163] Re-establishment information
of a radio channel [0164] Information related to beam sweeping,
beam reconfiguration, or beam change for beam forming [0165]
Information related to physical channel synchronization acquisition
[0166] Update information of location information [0167] Mobility
state or buffer status report
[0168] The terminal (e.g., the terminal operating in the RRC idle
state or the RRC inactive state) may transmit small data and/or a
small signaling message using the 4-step random access procedure
shown in FIG. 6. The small signaling message may be a MAC signaling
message (e.g., a control message of the MAC layer) or an RRC
signaling message (e.g., a control message of the RRC layer). In
order to perform the above-described operation, the terminal may
transmit the RA MSG3 including the following information
element(s). [0169] Identifier (ID) of the terminal [0170]
Information informing a transmission request of an uplink small
packet (or, small data and/or small signaling message) [0171]
Information indicating an uplink data or the size of the uplink
data (e.g., length indicator (LI)). The information indicating the
size of the uplink data may indicate the size of MAC PDU or the
number of MAC PDUs. [0172] Information indicating an uplink
signaling message (e.g., uplink bearer message) and/or the size of
the uplink signaling message (e.g., LI). The information indicating
the size of the uplink signaling message may indicate the size of
RRC message or the number of RRC messages. [0173] Logical channel
identifier (e.g., LCD) of an uplink data bearer or an uplink
signaling bearer [0174] Uplink buffer size information (e.g., BSR)
[0175] Information indicating whether the size of the small packet
meets a preconfigured condition [0176] Control message for
connection configuration request [0177] Information requesting
uplink resource allocation [0178] Measurement result of a radio
channel [0179] Information on a desired terminal state after
completion of transmission of the small packet
[0180] The information indicating whether the size of the small
packet meets a preconfigured condition may be information
indicating whether the size of the small packet to be transmitted
by the terminal is less than or equal to a preconfigured threshold.
The base station may determine a size and/or MCS level of an uplink
resource allocated to the terminal based on the information
indicating whether the size of the small packet meets a
preconfigured condition. Here, the threshold (e.g., a comparison
reference value of the size of the small packet) may be
preconfigured in the communication system according to a class of
the terminal, the capability of the terminal, the type of the
bearer, and/or the type (e.g., coverage) of the base station.
Alternatively, the base station may determine the threshold
according to the class of the terminal, the capability of the
terminal, the type of the bearer, and/or the type (e.g., coverage)
of the base station, and inform the determined threshold to the
terminal by using system information, an RRC message, a MAC message
(e.g., MAC CE), and/or a PHY message (e.g., DCI).
[0181] When the RA MSG3 includes the above-described information
elements, a control field(s) indicating one or more among
information indicating whether each information element is
included, information on attribute(s) of the corresponding data
(or, control information), and information on the size of the
corresponding data (or, control information) may be configured in
form of a MAC header, logical channel identifier (e.g., LCD), or
MAC CE.
[0182] The terminal may transmit the small uplink packet through
the random access procedure shown in FIG. 6. When transmission of
the uplink small packet is required, the terminal operating in the
RRC inactive state or the RRC idle state may trigger execution of
the random access procedure shown in FIG. 6. When a condition
preconfigured for transmission (e.g., intermittent transmission) of
the uplink small packet is satisfied, the terminal may perform the
step S602 using the RA MSG1 meeting the above-described
condition.
[0183] In this case, the base station may configure the RA MSG1 for
transmission of the uplink small packet (e.g., intermittent
transmission) to be distinguished. For example, the RA MSG1 may be
configured to be distinguished according to the size and/or type
(e.g., form) of the uplink small packet to be transmitted by the
terminal. The terminal may transmit the RA MSG1 configured for
transmission of the uplink small packet. When the RA MSG1 is
received from the terminal, the base station may transmit an RA
MSG2 to the terminal in response to the RA MSG1. The RA MSG2 may
include resource allocation information for transmission of an RA
MSG3 including the uplink small packet.
[0184] As another exemplary embodiment, the base station may
transmit uplink scheduling information for transmission of the
uplink small packet to the terminal in a preconfigured period
(e.g., a period or window preconfigured after the step S602 is
performed). The uplink scheduling information may be transmitted on
a physical layer control channel (e.g., PDCCH). In this case, a
scheduling identifier may be an RA-RNTI or a dedicated scheduling
identifier for small packet (e.g., small packet (SM)-RNTI). For
example, a cyclic redundancy check (CRC) of a DCI including the
uplink scheduling information of the small packet may be scrambled
by the RA-RNTI or SM-RNTI. The SM-RNTI may be used for transmission
of the small packet and/or transmission of the scheduling
information of the small packet.
[0185] The terminal may identify the uplink scheduling information
included in the RA MSG2 obtained using the RA-RNTI. Alternatively,
the terminal may perform a monitoring operation on a downlink
channel (e.g., PDCCH and/or PDSCH) using the SM-RNTI, and identify
the uplink scheduling information included in a DCI obtained by the
monitoring operation. The uplink scheduling information may be
transmitted to the terminal using a PDCCH and/or a PDSCH. The
terminal may transmit the small packet to the base station in a
resource indicated by the uplink scheduling information. That is,
the terminal may transmit the uplink small packet meeting the
condition for small packet transmission to the base station in the
step S604 by using the RA MSG3 according to the uplink scheduling
information of the RA MSG2.
[0186] In case that the RA MSG1 for transmission (e.g.,
intermittent transmission) of the small packet is not configured to
be distinguished, the terminal transmitting the RA MSG1 may receive
the RA MSG2 according to the random access procedure shown in FIG.
6. The terminal may transmit control information to the base
station by using the RA MSG3 for transmission of the small
packet.
[0187] The base station may identify the control information
included in the RA MSG3 of the step S604 or the control message
(e.g., RRC control message and/or MAC control message) received
after the random access procedure shown in FIG. 6. The control
information may include BSR information, information indicating the
size of the small packet, information indicating whether the size
of the small packet meets a preconfigured condition, and/or
information on a desired terminal state after completion of the
transmission of the small packet. The base station may determine
whether to transition the state of the terminal based on the
control information. For example, when the terminal operating in
the RRC inactive state or the RRC idle state can transmit an uplink
packet (e.g., small packet) without a state transition, the base
station may control (or, instruct) the terminal to transmit the
uplink packet in the RRC inactive state. Alternatively, the base
station may control (or instruct) the terminal that has completed
the transmission of the uplink packet to transition to the RRC
inactive state or the RRC idle state. Here, the uplink packet may
be uplink data and/or uplink control information.
[0188] When the size of the uplink packet requested by the terminal
to be transmitted is greater than or equal to the threshold, the
base station may control (or instruct) the terminal to transmit the
uplink packet after the terminal transitions to the RRC connected
state. Alternatively, the base station may control (or instruct)
the terminal performing a random access procedure to perform uplink
communication or downlink communication after the terminal
transitions to the RRC connected state or the RRC inactive state.
In order to support the above operation, the base station may
control or instruct the terminal performing a random access
procedure to perform uplink communication or downlink communication
after the terminal transitions to the RRC connected state or the
RRC inactive state by transmitting a response message (e.g., RA
MSG2) or a separate control message.
[0189] The base station may transmit uplink scheduling information
of the small packet to the terminal in the step S604 or after the
step S604. The uplink scheduling information may be transmitted on
a PDCCH or PDSCH. In this case, the scheduling identifier may be
the C-RNTI or SM-RNTI included in the RA MSG2 in the step S603. The
terminal may obtain the uplink scheduling information using the
C-RNTI or SM-RNTI, and transmit the small packet to the base
station in a resource indicated by the uplink scheduling
information.
[0190] In the step S604, the terminal may transmit a MAC control
message including control information. In this case, information
indicating whether the control information is present, a value of
the control information, and/or a configuration parameter range may
be transferred in form of a MAC subheader or header or in form of a
MAC subPDU or MAC PDU. In order to support the above operation, a
separate logical channel identifier may be configured.
[0191] FIG. 7 is a sequence chart illustrating a second exemplary
embodiment of a random access procedure in a communication
system.
[0192] Referring to FIG. 7, a communication system may include a
base station, a terminal, and the like. The base station may be the
base station 110-1, 110-2, 110-3, 120-1, or 120-2 shown in FIG. 1,
and the terminal may be the terminal 130-1, 130-2, 130-3, 130-4,
130-5, or 130-6 shown in FIG. 1. The base station and the terminal
may be configured to be the same or similar to the communication
node shown in FIG. 2. A random access procedure may be performed in
two steps.
[0193] The base station may transmit system information and/or a
control message including configuration information of a radio
resource (e.g., uplink radio resource) for the random access
procedure to the terminal (S701). The terminal may obtain the
configuration information of the radio resource for the random
access procedure by receiving the system information and/or the
control message from the base station. Here, the control message
may be a dedicated control message. The system information and/or
dedicated control message may be the same as or similar to the
system information and/or dedicated control message in the step
S601 shown in FIG. 6.
[0194] The terminal may transmit an RA MSG-A to the base station
using the radio resource configured by the base station (S702). The
RA MSG-A may include an RA preamble and a terminal identifier
(e.g., UE ID, C-RNTI). In addition, the RA MSG-A may further
include uplink data and/or control information. In the 2-step
random access procedure, a message 1 may be referred to as the `RA
MSG-A` or `MSG-A`, and the RA MSG-A may be distinguished from the
RA MSG1 in the 4-step random access procedure.
[0195] The RA MSG-A may include an RA preamble and an RA payload.
In the 2-step random access procedure, the RA preamble may be
referred to as a `2-step-RA preamble`, and in the 2-step random
access procedure, the RA payload may be referred to as a `2-step-RA
payload`. The RA preamble of the RA MSG-A may be selected by the
MAC layer of the terminal. The RA payload of the RA-MSG-A may be
generated by the MAC layer or the RRC layer. The RA preamble
selected by the MAC layer of the terminal and the RA payload
generated by the MAC layer or RRC layer of the terminal may be
delivered to the physical layer. The RA payload of the RA MSG-A may
include one or more among the terminal identifier (e.g., UE ID,
C-RNTI), uplink data, and control information.
[0196] The control information may include a BSR, measurement
result information (e.g., quality information), BFR request
information, RLF report information, request information of RRC
connection setup, request information of RRC connection
re-establishment, resumption request information, and transmission
request information of system information. When the CBRA procedure
or the CFRA procedure is performed, the RA payload may include the
terminal identifier. The uplink radio resource for transmission of
the RA preamble may be configured independently of the uplink radio
resource for transmission of the RA payload.
[0197] For example, the radio resources configured (or allocated)
for the radio access procedure may be non-contiguous in the time
domain or frequency domain. Alternatively, the radio resources
configured (or allocated) for the radio access procedure may be
contiguous in the time domain or frequency domain. The radio
resources for the radio access procedure may be radio resources
configured (or allocated) in different schemes. Alternatively, the
radio resources for the radio access procedure may be radio
resources defined by a different physical layer channel.
[0198] The expression that the radio resources for the radio access
procedure are different may mean that one or more among the
positions of the radio resources in the time domain or frequency
domain, the indexes of the radio resources, the indexes of the RA
preambles, the transmission timing, and the offsets are configured
differently. The RA preamble or RA payload may be transmitted using
different radio resources. For example, the RA preamble may be
transmitted on a PRACH, and the RA payload may be transmitted on a
physical uplink shared channel (PUSCH).
[0199] In order to configure the transmission resource for the RA
preamble of the RA MSG-A differently from the transmission resource
for the RA payload of the RA MSG-A, the uplink radio resource for
transmission of the RA payload of the RA MSG-A (e.g., PUSCH
configured for transmission of the RA payload of the RA MSG-A) may
be configured to correspond to the RA preamble of the RA MSG-A.
That is, a mapping relationship between the uplink radio resource
for transmitting the RA preamble of the RA MSG-A and the uplink
radio resource for transmitting the RA payload of the RA MSG-A may
be configured.
[0200] For example, the transmission resource of the RA preamble
may be mapped one-to-one with the transmission resource of the RA
payload. In this case, one PRACH may be mapped to one PUSCH.
Alternatively, a plurality of transmission resources of the RA
preamble may be mapped to one transmission resource of the RA
payload. In this case, a plurality of PRACHs may be mapped to one
PUSCH. Alternatively, one transmission resource of the RA preamble
may be mapped to a plurality of transmission resources of the RA
payload. In this case, one PRACH may be mapped to a plurality of
PUSCHs. In order to improve the reception quality of the RA
payload, the RA payload may be repeatedly transmitted. The uplink
radio resources for the repetitive transmission of the RA payload
may be configured, and the corresponding uplink radio resources may
be mapped to the transmission resources of the RA preamble.
[0201] For example, when the transmission resource of the RA MSG-A
is preconfigured or when the RA preamble of the RA MSG-A is
transmitted through a preconfigured region (or group), the base
station may configure radio resources for the repetitive
transmissions of the RA payload of the RA MSG-A. Therefore, when a
coverage expansion function is applied or when a preconfigured
reference condition is satisfied, the terminal may select RA
preamble resources or RA preamble index for the repetitive
transmissions of the RA payload, and may repeatedly transmit the RA
payload based on the selected resource or index. The terminal may
repeatedly transmit the RA payload using uplink radio resources
mapped to the RA preamble index. The uplink radio resources (e.g.,
repeated radio resources) for transmission of the RA payload may be
configured within a preconfigured period in the frequency domain or
time domain. Information on a mapping relationship of the uplink
radio resources for transmission of the RA MSG-A may be transmitted
to the terminal through system information and/or an RRC
message.
[0202] When the 2-step random access procedure is performed in a
non-contention scheme, the transmission resources of the RA
preamble and/or the RA payload of the RA MSG-A may be allocated
dedicatedly to the terminal. In the CFRA procedure, resource
information of the RA preamble configured dedicatedly for the
terminal may include an SS/PBCH resource list, a CSI-RS resource
list, an SS/PBCH index, a CSI-RS index, an RA preamble index, and
the like. The transmission resource of the RA payload of the RA
MSG-A may be determined based on the mapping relationship (e.g.,
one-to-one mapping relationship or many-to-one mapping
relationship) between the transmission resource of the RA preamble
and the transmission resource of the RA payload. In the CFRA
procedure (e.g., 2-step CFRA procedure), the resource information
of the RA payload configured dedicatedly for the terminal may
include allocation information of an uplink radio resource, beam
configuration information, MCS information, etc. for transmission
of the RA payload.
[0203] In the 2-step random access procedure, the transmission
resource of the RA preamble may be contiguous with the transmission
resource of the RA payload in the time domain. The transmission
resource of the RA payload may be allocated within a time window.
The terminal performing the 2-step random access procedure may
transmit the RA payload using a radio resource contiguous with the
RA preamble. Alternatively, the terminal may transmit the RA
payload by using a radio resource within the time window.
[0204] Alternatively, parameter(s) for allocation of the
transmission resource of the RA preamble and the transmission
resource of the RA payload may include a frequency offset and/or a
time offset. Accordingly, the terminal may transmit the RA payload
using a radio resource for the RA payload mapped to the RA
preamble. Alternatively, the terminal may randomly select one or
more radio resources among radio resources configured for
transmission of the RA payload, and may transmit the RA payload
using the selected radio resource(s).
[0205] The RA payload of the RA MSG-A transmitted in the step 702
may be configured to be the same or similar to the RA MSG3
transmitted in the step S604 shown in FIG. 6. For example, the RA
payload of the RA MSG-A may include one or more among the
identifier, capability, property, mobility state, and location
information of the terminal, the reason for attempting the access
procedure, request information of beam failure recovery, a
measurement result on a base station (or cell) in the CA
environment, request information of activation/deactivation of the
CA, BWP switching request information, BWP deactivation/activation
request information, uplink data (e.g., small packet), size of the
uplink data (e.g., small packet), uplink buffer size information
(e.g., BSR), control message for requesting connection
configuration, information indicating whether the size of the
uplink small packet meets a preconfigured condition, request
information of uplink resource allocation, and a measurement result
of a radio channel. The control information for transmission of the
uplink small packet included in the RA MSG3 shown in FIG. 6 may be
included in the RA payload of the RA MSG-A in FIG. 7. That is, the
terminal may transmit the RA payload including control information
for transmission of the uplink small packet to the base
station.
[0206] When the RA payload is transmitted together with the RA
preamble in the step 702, the RA payload may include one or more
among the terminal identifier, uplink data, and control
information. The attribute of the uplink data, the length of the
uplink data, the attribute of the control information, the length
of the control information, and whether the control information is
included may be indicated by a MAC header, logical channel
identifier (e.g., LCID), or MAC CE. For transmission timing
adjustment (e.g., adjustment of a TA value) or transmission power
control, the terminal may insert a preamble, pilot symbol, or
reference signal in the first symbol or some symbols within the RA
payload of the RA MSG-A.
[0207] The base station may receive the RA MSG-A from the terminal,
and may obtain the RA preamble and RA payload included in the RA
MSG-A. In addition, the base station may obtain one or more among
the terminal identifier, uplink data, and control information from
the RA payload. The base station may generate an RA MSG-B (e.g.,
message 2, RAR) in response to the RA MSG-A, and may transmit the
RA MSG-B to the terminal (S703). The terminal may receive the RA
MSG-B from the base station, and may identify information
element(s) included in the RA MSG-B. The RA MSG-B may be referred
to as a `MSG-B`.
[0208] The RA MSG-B may include one or more among a backoff
indicator (BI), uplink radio resource allocation information, the
RA preamble (i.e., index of the RA preamble) of the RA MSG-A,
transmission timing adjustment information (e.g., TA value or TA
Command), scheduling identifier (e.g., C-RNTI, temporary cell
(TC)-RNTI, etc.), and terminal identifier for contention resolution
(e.g., contention resolution ID (CRID)).
[0209] The RA MSG-B (e.g., MAC PDU) may include one or more MAC
subPDUs. Each of the one or more MAC subPDUs included in the RA
MSG-B may be configured based on one of the following configuration
schemes. Information indicating the configuration scheme of the MAC
subPDU may be included in a MAC subheader of the corresponding MAC
subPDU. The MAC subPDU may mean `MAC sub PDU`. [0210] Configuration
scheme #1: a MAC subheader including a backoff indicator (BI)
[0211] Configuration scheme #2: a MAC subheader and a fallback RAR
[0212] Configuration scheme #3: a MAC subheader and a successful
RAR [0213] Configuration scheme #4: a MAC subheader and a MAC
service data unit (SDU) (e.g., data or control information) [0214]
Configuration scheme #5: a MAC subheader and a padding
[0215] When the RA MSG-B is scheduled by the C-RNTI assigned to the
terminal or when the RA MSG-B includes the terminal identifier
(e.g., UE contention resolution ID) included in the RA MSG-A, the
terminal may determine that the contention is resolved. That is,
the terminal may determine that the 2-step random access procedure
is completed.
[0216] When a CRC of DCI including scheduling information of the
PDSCH on which the RA MSG-B (e.g., RAR for the RA MSG-A) is
transmitted is scrambled by the C-RNTI, and the RA MSG-B including
TA information and/or a UL grant is received within an RAR window
(or before a timer expires), the terminal may determine that the
contention for the 2-step random access procedure is resolved.
Here, the TA information may be a TA value or a TA command.
[0217] A specific field (or bit) of the PDCCH (e.g., DCI or UCI)
may indicate that the RA MSG-B scheduled by the PDCCH is an RA
MSG-B scheduled by the C-RNTI. Alternatively, a field of the MAC
subheader or a logical channel identifier (LCD) for transmission of
the MAC CE for the RA MSG-B may indicate that the RA MSG-B
scheduled by the PDCCH is an RA MSG-B scheduled by the C-RNTI.
[0218] In the 4-step random access procedure, the RAR window may
start at the ending time point of the transmission of RA MSG1. In
the 2-step random access procedure, the RAR window may start at the
ending time point of the transmission of the RA payload of the RA
MSG-A. When the RA MSG-B (e.g., RA MSG-B scheduled by the C-RNTI)
including the TA information and/or UL grant is not received within
the RAR window (or before a timer expires), the terminal may
determine that the contention for the 2-step random access
procedure is not resolved.
[0219] When the RA MSG-B scheduled by the C-RNTI is transmitted in
response to the RA MSG-A in the 2-step random access procedure, the
PDCCH (e.g., DCI or UCI) may include the TA information, indicator
informing that the corresponding PDCCH includes scheduling
information for a response to the RA MSG-A, and the like. The RA
MSG-B may be transmitted in form of a MAC message (e.g., MAC CE) or
an RRC message. When the RA MSG-B is transmitted in form of a MAC
message, the RRC layer of the base station obtaining the
information of the RA MSG-A may deliver parameter(s) to be included
in the RA MSG-B to the MAC layer of the base station, and the MAC
layer of the base station may generate the RA MSG-B in form of a
MAC CE. The RA MSG-B may include the terminal identifier obtained
through the RA payload of the RA MSG-A.
[0220] When the RA preamble of the RA MSG-A is allocated
dedicatedly to the terminal or when the radio resource of the RA
preamble of the RA MSG-A is mapped one-to-one with the radio
resource of the RA payload of the RA MSG-A, the RA MSG-B may not
include the index of the RA preamble received from the
terminal.
[0221] When the RA preamble of the RA MSG-A is allocated
dedicatedly to the terminal or when the RA payload of the RA MSG-A
includes the scheduling identifier (e.g., C-RNTI) assigned to the
terminal, the base station may transmit DCI including scheduling
information for the transmission resource of the RA MSG-B to the
terminal using the scheduling identifier assigned to the terminal.
That is, a CRC of the DCI may be scrambled by the scheduling
identifier assigned to the terminal. The terminal may receive the
DCI using the scheduling identifier assigned to the terminal,
obtain the scheduling information for the transmission resource of
the RA MSG-B included in the DCI, and receive the RA MSG-B in the
transmission resource indicated by the scheduling information.
[0222] In the step S703, the base station may transmit a PDCCH for
scheduling an uplink radio resource, a PDCCH (e.g., DCI) for the
RAR (e.g., RA MSG-B), or the RA MSG-B. The RA MSG-B may be
transmitted on a PDSCH. When only the PDCCH is transmitted in the
step S703, the corresponding PDCCH may include one or more among
allocation information (e.g., scheduling information) of an uplink
radio resource for the terminal, transmission timing adjustment
information (e.g., TA information), transmission power adjustment
information, backoff information, beam configuration information,
TCI state information, CS state information, state transition
information, PUCCH configuration information, the index of the RA
preamble included in the RA MSG-A, and allocation information of a
radio resource for transmission of the RA payload of the RA
MSG-A.
[0223] The beam configuration information may be information
indicating activation or deactivation of a specific beam. The TCI
state information may be information indicating activation or
deactivation of a specific TCI state. The CS state information may
be information indicating activation or deactivation of radio
resources allocated in the CS scheme. The state transition
information may be information indicating transition of the
operation state shown in FIG. 5. The state transition information
may indicate transition from the current operation state to the RRC
idle state, RRC inactive state, or RRC connected state.
Alternatively, the state transition information may indicate
maintaining the current operation state. The PUCCH configuration
information may be allocation information of a transmission
resource of an SR. Alternatively, the PUCCH configuration
information may be information indicating activation or
deactivation of a transmission resource of an SR.
[0224] The base station may transmit the control information
described in the step S703 on a PDSCH by transmitting only the
PDCCH. The control message transmitted on the PDSCH may include one
or more among allocation information (e.g., scheduling information)
of an uplink radio resource, transmission timing adjustment
information (e.g., TA information), transmission power adjustment
information, backoff information, beam configuration information,
TCI state information, CS state information, state transition
information, PUCCH configuration information, the index of the RA
preamble included in the RA MSG-A, and allocation information of an
uplink radio resource for transmission of uplink data and/or a
control message in a step S704.
[0225] In the procedure for generating and transmitting the RA
MSG-B, the base station may transmit the DCI including scheduling
information for transmission of the RA MSG-B by using an RA-RNTI or
the scheduling identifier (e.g., C-RNTI) assigned to the terminal.
That is, the CRC of DCI may be scrambled by the RA-RNTI or the
C-RNTI. The base station may transmit the RA MSG-B to the terminal
using the PDSCH indicated by the DCI.
[0226] When the terminal successfully receives the RA MSG-B from
the base station, the 2-step random access procedure may be
terminated. The terminal receiving the RA-MSG B may transmit uplink
data and/or a control message to the base station by using uplink
scheduling information (e.g., scheduling information included in
the RA-MSG B) (S704).
[0227] Information indicating whether the base station (or cell)
allows the execution of the 2-step random access procedure and/or a
condition for performing the 2-step random access procedure may be
transmitted to the terminal through system information transmitted
in a broadcast scheme, a control message transmitted in a multicast
scheme, or a dedicated control message. The information indicating
whether the base station (or cell) allows the execution of the
2-step random access procedure may be information indicating
whether the base station allows the terminal located in a service
area to attempt to access through the 2-step random access
procedure, information indicating whether the base station restrict
the access attempt of the terminal located in a service area
through the 2-step random access procedure, or information
indicating whether the base station partially restricts the access
attempt of the terminal located in a service area through the
2-step random access procedure.
[0228] When the access attempt through the 2-step random access
procedure is restricted, the base station may inform the terminal
of a restriction condition of the 2-step random access procedure.
When the access attempt through the 2-step random access procedure
is partially restricted, the base station may inform the terminal
of a partial restriction condition of the 2-step random access
procedure. When the base station does not allow the 2-step random
access procedure or when the restriction condition or the partial
restriction condition of the 2-step random access procedure is met,
the terminal may not attempt the 2-step random access
procedure.
[0229] When an execution condition (e.g., allowance condition) of
the 2-step random access procedure is met, the terminal may perform
the 2-step random access procedure. For example, if a quality of a
radio channel measured by the terminal is equal to or greater than
a threshold (e.g., reference value) configured by the base station,
the terminal may perform the 2-step random access procedure. When
the quality of the radio channel measured by the terminal is less
than a threshold configured by the base station, the terminal may
perform the 4-step random access procedure. Alternatively, when the
quality of the radio channel measured by the terminal is less than
a threshold configured by the base station, the terminal may
perform the 2-step random access procedure. When the quality of the
radio channel measured by the terminal is greater than or equal to
a threshold configured by the base station, the terminal may
perform the 4-step random access procedure.
[0230] For example, the quality of the radio channel may be
measured as a received signal strength indicator (RSSI), a received
signal code power (RSCP), a reference signal received power (RSRP),
or a reference signal received quality (RSRQ). Alternatively, the
quality of the radio channel may be measured as other parameters
(e.g., a reference parameter for measuring a quality of a radio
section between the base station (or, cell or TRP) and the
terminal).
[0231] The RA preamble (e.g., signature) of the RA MSG1 in the
4-step random access procedure may be configured to be the same as
the RA preamble (e.g., signature) of the RA MSG-A in the 2-step
random access procedure. In the procedure of generating the RA
preamble of the RA MSG1 and the RA MSG-A, a code sequence may be
generated using the same code generation formula.
[0232] Each of the index and the transmission resource of the RA
preamble of the RA MSG1 in the 4-step random access procedure may
be configured to be different from each of the index and the
transmission resource of the RA preamble of the RA MSG-A in the
2-step random access procedure. The transmission resource of the RA
preamble of the RA MSG1 may be configured to be distinguished from
the transmission resource of the RA preamble of the RA MSG-A in the
time and/or frequency domain. In the frequency domain, the
transmission resource of the RA preamble may include one or more of
frequency band information, PRB information, CRB information,
subcarrier information, and beam information according to a
beamforming technique. In the time domain, the transmission
resource of the RA preamble may be configured or indicated in units
of a radio frame, subframe, TTI, slot, mini-slot, symbol, or
specific time interval. The base station may determine whether the
4-step random access procedure or the 2-step random access
procedure is performed based on the RA preamble received from the
terminal or the radio resource through which the RA preamble is
received.
[0233] The terminal may perform a procedure for transmission (e.g.,
intermittent transmission) of an uplink small packet by using the
random access procedure shown in FIG. 7. When transmission of an
uplink small packet is required, the terminal operating in the RRC
inactive state or the RRC idle state may trigger the transmission
operation of the RA MSG-A of FIG. 7. When a preconfigured condition
for transmission of the uplink small packet is met, the terminal
may perform the step S702 for transmission of the RA MSG-A meeting
the preconfigured condition. In this case, the terminal may
transmit the RA payload including control information for
transmission of the uplink small packet and/or the small
packet.
[0234] The RA payload of the RA MSG-A may include one or more among
transmission request information of the uplink small packet,
information indicating the size of the uplink small packet (e.g.,
the size of MAC PDU and/or the size of RRC message), information
indicating the number of uplink small packets (e.g., the number of
MAC PDUs and/or the number of RRC messages), uplink buffer size
information (e.g., BSR), control message for connection
configuration request, indicating whether the size of the uplink
small packet meets a preconfigured condition, uplink resource
allocation request information, channel measurement result, and
information on a desired terminal state after completion of the
transmission of the small packet. When the above-described control
information is transmitted using a MAC control message, information
indicating whether the control information is present, a value of
the control information, and/or a configuration parameter range may
be transferred in form of a MAC subheader or header or in form or a
MAC subPDU or PDU. In order to support the above operation, a
separate logical channel identifier may be configured.
[0235] For transmission (e.g., intermittent transmission) of the
uplink small packet, the RA preamble of the RA MSG-A may be
configured to be distinguished. In this case, the terminal may
select the RA preamble of the RA MSG-A according to the size and/or
type (e.g., form) of the uplink small packet. That is, the terminal
may transmit the uplink small packet meeting the condition for
transmission of the small packet to the base station using the RA
payload of the RA MSG-Ain the step S702.
[0236] The base station may determine whether to transition the
operation state of the terminal based on the control information
included in the RA preamble of the RA MSG-A and/or the control
message (e.g., RRC control message and/or MAC control message)
received from the terminal after completion of the random access
procedure. Here, the control information may be BSR information,
information indicating the size of the uplink small packet, and/or
information indicating whether the size of the uplink small packet
meets a preconfigured condition.
[0237] For example, if the terminal operating in the RRC inactive
state or the RRC idle state can transmit the uplink packet (e.g.,
small packet) without a state transition, the base station may
control (or instruct) the terminal to transmit the uplink packet in
the RRC inactive state or the RRC idle state. Alternatively, the
base station may control (or instruct) the terminal that has
completed transmission of the uplink packet to transition the
operation state to the RRC inactive state or the RRC idle state.
Here, the uplink packet may be uplink data and/or uplink control
information.
[0238] When the size of the uplink packet requested by the terminal
to be transmitted is greater than or equal to a threshold, the base
station may control (or instruct) the terminal to transmit the
uplink packet after the terminal transitions to the RRC connected
state. Alternatively, the base station may control (or instruct)
the terminal performing the random access procedure to perform
uplink communication or downlink communication after the terminal
transitions to the RRC connected state or the RRC inactive state.
In order to support the above operation, the base station may
control (or instruct) the terminal performing the random access
procedure to perform uplink communication or downlink communication
after the terminal transitions to the RRC connected state or the
RRC inactive state by transmitting a response message (e.g., RA
MSG-B) or a separate control message.
[0239] The base station may transmit uplink scheduling information
of the small packet to the terminal in the step S704 or after the
step S704. The uplink scheduling information may be transmitted on
a PDCCH or PDSCH. In this case, a scheduling identifier may be the
C-RNTI or SM-RNTI included in the RA MSG-B of the step S703. The
terminal may obtain the uplink scheduling information by using the
C-RNTI or SM-RNTI, and transmit the small packet to the base
station in a resource indicated by the uplink scheduling
information.
[0240] The small packet may be transmitted using a channel (e.g.,
uplink channel) preconfigured for transmission of the small packet
instead of the random access procedure (e.g., RA message, channel)
shown in FIG. 6 or 7. For example, the base station may configure a
pre-allocated uplink resource (e.g., pre-allocated uplink resource
(PUR)) for transmission of the small packet, and may transmit
configuration information of the PUR to the terminal. The terminal
may receive the configuration information of the PUR from the base
station, and may transmit the small packet by using the PUR
indicated by the configuration information. The PUR for
transmission of the small packet may be configured (e.g.,
allocated) in a contention-based uplink channel or a
contention-free uplink channel. The PUR may be preconfigured for
transmission of a small packet. Alternatively, the PUR may be a
resource (e.g., channel) allocated to a terminal, a terminal group,
or a terminal existing (e.g., located) in a service area that
satisfies a condition configured by the base station.
[0241] Similarly to the RA MSG-A in the 2-step random access
procedure shown in FIG. 7, the PUR may be configured with a
resource through which bit stream information (e.g., sequence
information) having a preconfigured pattern in form of a preamble,
reference signal, or pilot symbol is transmitted and/or an uplink
channel (e.g., PUSCH) through which a small packet is transmitted.
For example, the PUR may be configured with an uplink resource
(e.g., uplink channel) through which symbols (e.g., signal) having
a preconfigured pattern in form of a preamble, reference signal, or
pilot symbol are transmitted. The preamble (or signal) may be
configured to be located in the first symbol or the last symbol of
the uplink channel in the time domain. The preamble (or signal) may
be configured to be located in a specific subcarrier of the uplink
channel in the frequency domain. The preamble (or signal) may be
configured to be mapped to a specific RE(s) of the uplink channel
in the time-frequency domain.
[0242] The configuration information of the uplink channel (e.g.,
PUR) for transmission of the small packet may include an index of
the bit stream (e.g., sequence), PUSCH allocation information, MCS
information, HARQ related information, transmission timing
information, and/or RE mapping information of a reference signal
(or preamble). The index of the bit stream (e.g., sequence) may
mean identification information capable of distinguishing a
corresponding bit stream (e.g., sequence), such as an index of the
RA preamble or an index of the reference signal. The transmission
timing information may mean a system frame number (SFN), a frame
index, a subframe index, a slot index, a mini-slot index, or a
symbol index for transmission of the small packet, an offset (e.g.,
offset for a SFN, frame, subframe, slot, mini-slot, or symbol) used
to estimate a transmission time (or, transmission time point),
and/or a transmission window size. The PUSCH allocation information
may mean time domain allocation information and/or frequency domain
allocation information of radio resources (e.g., physical resource
block (PRB)) constituting the PUR.
[0243] The configuration information of the PUR for transmission of
the small packet may be preconfigured (e.g., allocated) for each
terminal or terminal group. Alternatively, the base station may
transmit a signaling message (e.g., signaling message for
transmission of system information) including the configuration
information of the PUR for transmission of the small packet to the
terminal. When the PUR is allocated to a terminal or a terminal
group, a control message for connection configuration or a control
message for state transition (or connection release) may include
the configuration information of the PUR for transmission of the
small packet.
[0244] The PUR and/or PUSCH resource for transmission of the small
packet may be configured as one or more PRBs using consecutive
radio resources. Here, the plurality of PRBs may be PRBs spaced
apart in the time domain and/or the frequency domain. When a small
packet occurs in the terminal, the terminal may transmit the small
packet to the base station using a preconfigured PUR (e.g., PRB(s)
of the PUR) or a PUR (e.g., PRB(s) of the PUR) allocated by the
base station.
[0245] When the terminal desires to transmit an uplink small packet
by using the PUR, the terminal may transmit one or more information
elements (e.g., control information) among transmission request
information of the uplink small packet, the size of the uplink
small packet (e.g., MAC PDU size and/or RRC message size),
information indicating the number of small uplink packets (e.g.,
the number of MAC PDUs and/or the number of RRC messages), uplink
buffer size information (e.g., BSR information), control message
for connection configuration request, information indicating
whether the size of the uplink small packet meets a preconfigured
condition, uplink resource allocation request information, channel
measurement result, and/or a desired terminal state after
completion of transmission of the small packet. When the
above-described control information is included in a MAC control
message, information indicating when \the control information is
present, a value of the control information, and/or a configuration
parameter range may be transferred in form of a MAC subheader or
header or in form or a MAC subPDU or PDU. In order to support the
above operation, a separate logical channel identifier may be
configured.
[0246] If one or more of the following conditions are met, a method
of transmitting a small packet using a PUR described above, a
method of transmitting a small packet in the 4-step random access
procedure shown in FIG. 6, and/or a method of transmitting a small
packet in the 2-step random access procedure shown in FIG. 7 may be
used. [0247] Condition #1: a case when the size of the small packet
is less than or equal to a preconfigured size (e.g., several bytes
or tens of bytes) [0248] Condition #2: a case when the channel
measurement result satisfies a preconfigured condition (e.g.,
reference condition for small packet transmission) [0249] Condition
#3: a case when the service type of the small packet (e.g., quality
of service (QoS) flow, bearer type) satisfies a preconfigured
condition [0250] Condition #4: a case when a logical channel
identifier, bearer identifier, or QoS flow ID is associated with
the small packet [0251] Condition #5: a case when a transmission
timing of the uplink small packet satisfies a preconfigured
condition [0252] Condition #6: a case when the small packet is for
emergency service
[0253] Meanwhile, the base station may perform transmission (e.g.,
intermittent transmission) of a downlink small packet using a
paging procedure (e.g., paging message, paging channel).
Alternatively, the base station may transmit the small packet to a
terminal (or, terminal group) using a downlink channel (e.g.,
pre-allocated downlink resource (PDR)) preconfigured (e.g.,
allocated) for transmission of the small packet.
[0254] The small packet may be transmitted in a paging procedure
based on a paging-RNTI (P-RNTI). In this case, the base station may
perform a transmission operation of control information indicating
downlink reception, transmission operation of scheduling
information for downlink reception, and/or transmission operation
of a downlink small packet by using a channel (or, message) for the
paging procedure.
[0255] When a small packet is transmitted using the PDR, scheduling
information for a channel for transmission of the small packet
(e.g., a field included in the DCI) may further include control
information indicating downlink reception (e.g., monitoring of the
PDR). Alternatively, the base station may transmit scheduling
information for downlink reception on a PDCCH and/or PDSCH in order
to transmit the small packet. The base station may transmit the
small packet on a downlink channel (e.g., PDSCH).
[0256] FIG. 8 is a timing diagram illustrating a first exemplary
embodiment of a method of transmitting and receiving a small packet
in a communication system.
[0257] Referring to FIG. 8, a communication system may include a
base station, a terminal, and the like. The base station may be the
base station 110-1, 110-2, 110-3, 120-1, or 120-2 shown in FIG. 1,
and the terminal may be the terminal 130-1, 130-2, 130-3, 130-4,
130-5, or 130-6 shown in FIG. 1. The base station and the terminal
may be configured to be the same or similar to the communication
node shown in FIG. 2.
[0258] The base station may generate an SM indicator (e.g., SM_Ind)
indicating presence of downlink data and/or signaling message. The
downlink data and/or signaling message may be a small packet. The
base station may transmit the SM indicator to the terminal (S801).
The SM indicator may be transmitted within an SM window (e.g.,
transmission window). The terminal may receive the SM indicator
from the base station, and may determine that a small packet (e.g.,
downlink data and/or signaling message) to be transmitted to the
terminal exists in the base station based on the SM indicator. The
SM indicator may be included in a DCI, and the DCI including the SM
indicator may be transmitted on a PDCCH. The CRC of the DCI
including the SM indicator may be scrambled by a P-RNTI or SM-RNTI.
The SM-RNTI in the paging procedure may be the same as the SM-RNTI
for uplink transmission in the random access procedure.
Alternatively, a separate SM-RNTI may be configured for a paging
channel (e.g., paging channel (PCH)) for receiving a small packet,
receiving PDR configuration information, or transmitting a small
packet.
[0259] In order to transmit a downlink small packet or to indicate
transmission of the downlink small packet by using a paging message
or PDR, a reception periodicity (e.g., monitoring periodicity,
reception occasion, monitoring occasion) of a DCI having a CRC
scrambled (or masked) by an RNTI (e.g., P-RNTI, SM-RNTI, C-RNTI,
semi-persistent scheduling (SPS)-RNTI, CG-RNTI) and/or a PDCCH
resource (e.g., control resource set (CORESET), search space)) may
be configured for each terminal or terminal group. The
above-described configuration information (e.g., configuration
information of the DCI reception periodicity, configuration
information of the PDCCH resource) may be transmitted in a
combination of one or more among system information, dedicated
control message, RRC control message, MAC control message, and PHY
control message.
[0260] The CRC of the DCI including the SM indicator may be
scrambled by the P-RNTI or SM-RNTI, and the PDCCH monitoring
periodicity (e.g., PDCCH monitoring occasion) for the DCI including
the SM indicator may be indicated by a modulo operation between
`the terminal identifier (or, terminal group identifier) and/or
PDCCH monitoring periodicity` and time information (e.g., SFN). The
PDCCH monitoring periodicity for the DCI including the SM indicator
may be configured in units of an SFN, frame, subframe, slot,
mini-slot, or symbol. The configuration information of the PDCCH
monitoring periodicity may include an index of a time resource,
offset for a time resource, and/or time window size (e.g., a time
window value, a time window length). The index of the time resource
may be an index of an SFN, frame, subframe, slot, mini-slot, or
symbol. The offset for the time resource may be an offset for an
SFN, frame, subframe, slot, mini-slot, or symbol.
[0261] The PDCCH resource through which the DCI having the CRC
scrambled by the P-RNTI or SM-RNTI is transmitted may be estimated
(or, configured) based on a parameter and/or a subcarrier offset
indicating a specific location in the frequency domain by using a
terminal identifier (or terminal group identifier) and/or a PDCCH
monitoring periodicity. The base station may transmit configuration
information of the parameter to the terminal by using a combination
of one or more of system information, dedicated control message,
RRC control message, MAC control message, and PHY control message.
The terminal (or terminal group) may receive the DCI by performing
a monitoring operation according to a preconfigured periodicity
and/or on the PDCCH resource (e.g., CORESET, search space), and
when the DCI includes the SM indicator, the terminal (or terminal
group) may determine that a small packet is to be transmitted.
Accordingly, the terminal may perform a small packet reception
operation.
[0262] The SM indicator may be transmitted in form of a bit or a
bitmap. In this case, some bits (e.g., reserved bits) of a short
message for a paging procedure, which is transmitted on a PDCCH
associated with the P-RNTI, may be configured as the SM indicator.
Alternatively, a field included in the DCI (e.g., the DCI related
to the P-RNTI) may be configured as the SM indicator.
[0263] In another exemplary embodiment, some bits of the control
information transmitted on the PDCCH associated with the C-RNTI or
SM-RNTI may be configured as the SM indicator. Alternatively, a
field included in the DCI (e.g., the DCI associated with the C-RNTI
or SM-RNTI) may be configured as the SM indicator. In another
exemplary embodiment, information transmitted on the PDCCH
associated with the SM-RNTI may indicate that a small packet is to
be transmitted.
[0264] In the SM indicator configured in form of a bitmap, each bit
of the bitmap may be set to distinguish a terminal group, a
terminal type, and/or a service type of the small packet.
Alternatively, in the SM indicator, a correspondence relationship
between each bit of the bitmap and (the terminal group, the
terminal type, and/or the service type of small packet) may be
defined.
[0265] The base station may transmit the small packet using a
paging channel (e.g., PCH) or a PDR (e.g., downlink-shared channel
(DL-SCH)) (S802). In this case, a CRC of a DCI including scheduling
information of a PDSCH through which the small packet is
transmitted may be scrambled by a P-RNTI or SM-RNTI. The scheduling
identifier for transmission of the small packet may be
preconfigured in the communication system. Alternatively, the base
station may configure a scheduling identifier for transmission of a
small packet for each terminal or terminal group, and may indicate
the scheduling identifier to the terminal (or terminal group) by
using a combination of one or more among system information,
dedicated control message, RRC control message, MAC control
message, and PHY control message.
[0266] The paging message or downlink scheduling information for
transmission of the small packet may be transmitted in the PDR. For
example, the downlink scheduling information of the small packet
may be transmitted on a PDSCH (or PDR) indicated by a DCI having a
CRC scrambled (or masked) by an RNTI (e.g., P-RNTI, SM-RNTI,
C-RNTI, SPS-RNTI, CG-RNTI). Alternatively, the DCI having the CRC
scrambled (or masked) by the RNTI (e.g., P-RNTI, SM-RNTI, C-RNTI,
SPS-RNTI, CG-RNTI) may include the downlink scheduling information
of the small packet. In this case, the DCI may include the SM
indicator as well as the downlink scheduling information of the
small packet. The DCI indicating that control information (e.g.,
bit) indicating downlink reception is valid may include the
downlink scheduling information of the small packet. When the
control information indicating downlink reception is not valid, the
DCI may include the scheduling information for transmission of a
paging message irrelevant to transmission of the small packet.
[0267] For transmission of the paging message or the small packet,
the small packet may be transmitted in the PDR. For example, the
base station may transmit the small packet to the terminal in the
PDCCH associated with an RNTI (e.g., P-RNTI, SM-RNTI, C-RNTI,
SPS-RNTI, CG-RNTI) or the PDSCH indicated by the DCI having the CRC
scrambled (or, masked) by the RNTI (e.g., P-RNTI, SM-RNTI, C-RNTI,
SPS-RNTI, CG-RNTI) (S802).
[0268] The control information transmitted through the PDCCH and/or
PDSCH for transmission of the downlink small packet may include one
or more information elements among the following information
elements. [0269] Information indicating downlink reception [0270]
Small packet attribute information [0271] Downlink transmission
timing information [0272] Configuration information and/or index
information of a BWP for transmission of the small packet [0273]
Beam configuration information, TCI state information, and/or TCI
state activation/deactivation indication information for
transmission of the small packet [0274] Time domain allocation
information and/or frequency domain allocation information [0275]
MCS information [0276] HARQ related information [0277] Repetitive
transmission related information [0278] CFRA configuration
information [0279] Information on a desired terminal state after
completion of reception of the downlink small packet
[0280] When the attribute information of the small packet is
transmitted in a MAC control message, information indicating
presence of the corresponding control information (e.g., small
packet attribute information), a value of the control information,
and/or a configuration parameter range may be transferred in form
of a MAC subheader or header or in form of a MAC subPDU or PDU. In
order to support the above operation, a separate logical channel
identifier may be configured.
[0281] The small packet attribute information may include one or
more among small packet bearer identification information (e.g.,
information indicating whether the bearer is a signaling radio
bearer (SRB) or a data radio bearer (DRB), bearer ID, etc.),
logical channel identifier (e.g., LCD), QoS Flow ID, information
indicating the size of the small packet, information indicating the
number of messages constituting the small packet (e.g., the number
of MAC PDUs and/or the number of RRC messages), source identifier
of the small packet (e.g., L2 or higher layer identifier, IP
address, port number), and target identifier of the small packet
(e.g., L2 or higher layer identifier, IP address, port number).
[0282] The downlink transmission timing information may include an
index of a time resource in which the small packet is transmitted,
an offset for estimating the time resource in which the small
packet is transmitted, and/or time window information (e.g., SM
window (i.e., reception window) size). The index of the time
resource may be an index of an SFN, frame, subframe, slot,
mini-slot, or symbol. The offset for estimating the time resource
may be an offset for an SFN, frame, subframe, slot, mini-slot, or
symbol. The time window (e.g., SM window, reception window) may be
a time period in which downlink communication is possible from the
reception time of the RNTI (e.g., P-RNTI or SM-RNTI) or the
reception time of the SM indicator. The time window may be
configured as a timer value.
[0283] The HARQ related information may be configuration
information for transmitting a HARQ response for the small packet
received in the paging procedure or the PDR. The HARQ related
information may include one or more among a HARQ process
identifier, resource configuration information of a PUCCH and/or
PUSCH for transmission of the HARQ response, resource configuration
information of a PUCCH and/or PUSCH for HARQ retransmission, and
HARQ retransmission timing information.
[0284] The repetitive transmission related information may refer to
control information required when the small packet transmitted in
the paging procedure is repeatedly transmitted to improve
reliability. The CFRA configuration information may mean
configuration of an RA MSG1 and/or an RA MSG-A for a CFRA procedure
when it is necessary to perform a random access procedure together
with the transmission procedure of the small packet according to
the paging operation or when it is necessary to perform a random
access procedure regardless of the transmission procedure of the
small packet according to the paging operation.
[0285] The base station may transmit the SM indicator to the
terminal based on the above-described method (S801), and may
transmit the small packet associated with the SM indicator to the
terminal based on the above-described method (S802). The SM
indicator and the small packet may be transmitted within the SM
window (e.g., transmission window). The SM window may start from
the transmission time point of the SM indicator. For example, the
timer for the SM window may operate from the transmission time
point of the SM indicator. The terminal (e.g., terminal operating
in the RRC inactive state or the RRC idle state) may receive the SM
indicator from the base station by performing a PDCCH monitoring
operation in an on-duration. The on-duration may be referred to as
an `active time` and may be configured by the base station.
[0286] The terminal may receive the small packet from the base
station by performing a downlink channel monitoring operation
within the SM window (e.g., reception window). Here, the monitoring
operation may be performed on the resource indicated by the
downlink scheduling information received from the base station. The
SM window may start from the reception time point of the SM
indicator. For example, the timer for the SM window may operate
from the reception time point of the SM indicator. When the SM
window ends (e.g., when the timer for the SM window expires), the
terminal may not perform the downlink channel monitoring
operation.
[0287] The terminal may transmit the HARQ response (e.g., ACK or
NACK) for the small packet to the base station (S803). The
transmission operation of the HARQ response for the small packet
may be performed according to the configuration of the base
station. The base station may receive the HARQ response for the
small packet from the terminal, and may determine whether to
retransmit the small packet based on the HARQ response.
[0288] The transmission of the HARQ response for the small packet
received in the paging procedure may be performed using an RA
preamble of the CFRA procedure. For example, an RA preamble #1
corresponding to ACK and an RA preamble #2 corresponding to NACK
may be preconfigured in the communication system. Alternatively,
the base station may configure the RA preamble #1 corresponding to
ACK and the RA preamble #2 corresponding to NACK, and may transmit
configuration information of the RA preambles #1 and #2 to the
terminal. The configuration information of the RA preambles #1 and
#2 may be transmitted to the terminal using a combination of one or
more among system information, RRC control message, MAC control
message, and PHY control message. The configuration information of
the RA preambles #1 and #2 may be included in a control message
transmitted through a PDCCH or PDSCH in the paging procedure, a
control message for connection configuration, and/or a control
message for state transition (e.g., connection release).
[0289] The terminal may receive the configuration information of
the RA preambles #1 and #2 from the base station. When the small
packet is successfully received (e.g., when decoding of the small
packet is successful), the terminal may transmit the RA preamble #1
corresponding to ACK to the base station. When the RA preamble #1
is received from the terminal, the base station may determine that
the decoding of the small packet in the terminal is successful. On
the other hand, when the reception of the small packet fails, the
terminal may transmit the RA preamble #2 corresponding to NACK to
the base station. When the RA preamble #2 is received from the
terminal, the base station may determine that the reception of the
small packet at the terminal has failed.
[0290] The base station may inform the terminal of whether to
receive the downlink small packet by transmitting the SM indicator
before a preconfigured time offset from a paging occasion (PO). For
example, the SM indicator according to the above-described method
may be transmitted before the preconfigured offset from a paging
occasion (e.g., a start time or end time of the paging occasion)
configured for the terminal or the terminal group. The terminal may
receive the SM indicator before the preconfigured offset from the
paging occasion (e.g., the start time or the end time of the paging
occasion). In this case, the terminal may perform the reception
operation of the downlink small packet according to the method
described above in the corresponding paging occasion. On the other
hand, the terminal may not receive the SM indicator at the
above-described time point (e.g., the time point before the
preconfigured offset from the paging occasion). In this case, the
terminal may not perform the operation of receiving the small
packet and/or the paging message in the corresponding paging
occasion.
[0291] For the transmission of the above-described SM indicator,
the following parameter(s) may be configured. The base station may
transmit the following parameter(s) to the terminal using a
combination of one or more among system information, dedicated
control message, RRC control message, MAC control message, and PHY
control message. [0292] Time offset indicating the transmission
time point of the SM indicator related to the paging occasion
[0293] Transmission period of the SM indicator [0294] CORESET
configuration information for transmission of the SM indicator
(e.g., CORESET identifier, CORESET resource index, and/or CORESET
configuration periodicity) [0295] Configuration information of the
SM window (e.g., transmission window, reception window)
[0296] When the small packet is generated by the base station or
the terminal, the base station and the terminal may perform a new
connection configuration procedure. In this case, a small packet
transmission/reception procedure may be performed between the
terminal operating in the RRC connected state and the base station.
Alternatively, the base station may transmit the small packet to
the terminal (e.g., the terminal operating in the RRC inactive
state or the RRC idle state) on a downlink channel (e.g., paging
channel or PDR) without performing a state transition operation.
The terminal (e.g., the terminal operating in the RRC inactive
state or the RRC idle state) may transmit the small packet to the
base station in an uplink channel (e.g., random access channel or
PUR) without performing a state transition operation.
[0297] The base station may transmit the configuration information
for transmission of the small packet to the terminal using a
combination of one or more among system information, dedicated
control message, RRC control message, MAC control message, and PHY
control message. Here, the dedicated control message may be a
message transmitted in a state transition procedure of the
terminal. The configuration information for transmission of the
small packet may include PUR resource allocation information (e.g.,
time domain allocation information and/or frequency domain
allocation information), PDR resource allocation information for
transmission of the small packet (e.g., time domain allocation
information and/or frequency domain allocation information), MCS
information, and/or HARQ-related information. The configuration
information for transmission of the small packet may be transmitted
to a specific terminal or a specific terminal group. Alternatively,
the configuration information for transmission of the small packet
may be transmitted to terminal(s) located in a service area that
meets a condition configured by the base station.
[0298] The radio resources for the PUR and/or the PDR may be
preconfigured. Alternatively, the PUR and/or PDR may be located
within a preconfigured BWP. In this case, the configuration
information of the PUR and/or PDR may include a BWP index
indicating the BWP in which the PUR and/or PDR is located. In the
communication system, a default BWP or an initial BWP may be used
as the BWP for the PUR and/or PDR. Alternatively, a dedicated BWP
for the PUR and/or PDR may be configured in the communication
system. In the above-described case(s), the configuration
information of the PUR and/or PDR may not include the BWP index.
When a dedicated BWP for the PUR and/or PDR is configured, the base
station may transmit configuration information of the dedicated BWP
for the PUR and/or PDR to the terminal by using a combination of
one or more among system information, dedicated control message,
RRC control message, MAC control message, and PHY control
message.
[0299] In the above-described small packet transmission procedure,
an encryption function according to the radio layer protocol may
not be applied. Alternatively, in the above-described small packet
transmission procedure, the encryption function according to the
radio layer protocol may be limitedly used. For example, an
encryption function using an encryption key may not be applied to
the small packet transmission procedure, and an integrity
protection function to check integrity of a transmitted message may
be applied to the small packet transmission procedure.
[0300] In the present disclosure, the radio channel quality may be
a channel state indicator (CSI), a received signal strength
indicator (RSSI), a reference signal received power (RSRP), a
reference signal received quality (RSRQ), or a signal to
interference and noise ratio (SINR). With respect to the operation
of the timer defined or described in the present disclosure,
although operations such as start, stop, reset, restart, or expire
of the defined timer are not separately described, they mean or
include the operations of the corresponding timer or a counter for
the corresponding timer.
[0301] In the present disclosure, the base station (or cell) may
refer to a node B (NodeB), an evolved NodeB, a base transceiver
station (BTS), a radio base station, a radio transceiver, an access
point, an access node, a road side unit (RSU), a radio remote head
(RRH), a transmission point (TP), a transmission and reception
point (TRP), or a gNB. In addition, the base station (or, cell) may
a CU node or a DU node to which the functional split is
applied.
[0302] In the present disclosure, the terminal may refer to a UE, a
terminal, an access terminal, a mobile terminal, a station, a
subscriber station, a mobile station, a portable subscriber
station, a node, a device), an Internet of Thing (IoT) device, or a
mounted apparatus (e.g., a mounted module/device/terminal or an
on-board device/terminal).
[0303] The exemplary 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.
[0304] Examples of the computer readable medium may include a
hardware device such as 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.
[0305] 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.
* * * * *