U.S. patent application number 16/673297 was filed with the patent office on 2020-05-07 for method and apparatus for transmitting and receiving data and feedback in wireless communication system.
This patent application is currently assigned to Samsung Electronics Co., Ltd.. The applicant listed for this patent is Samsung Electronics Co., Ltd.. Invention is credited to Jonghyun BANG, Jinyoung OH, Sungjin PARK, Hyunseok RYU, Cheolkyu SHIN, Jeongho YEO.
Application Number | 20200145148 16/673297 |
Document ID | / |
Family ID | 70459857 |
Filed Date | 2020-05-07 |
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United States Patent
Application |
20200145148 |
Kind Code |
A1 |
YEO; Jeongho ; et
al. |
May 7, 2020 |
METHOD AND APPARATUS FOR TRANSMITTING AND RECEIVING DATA AND
FEEDBACK IN WIRELESS COMMUNICATION SYSTEM
Abstract
A method of performing communication by a terminal in a wireless
communication system includes storing feedback information for data
transmitted from a base station in at least one hybrid automatic
repeat request (HARQ) process; receiving control information
including an indication of feedback triggering; and transmitting
the stored feedback information based on the indication of the
feedback triggering.
Inventors: |
YEO; Jeongho; (Gyeonggi-do,
KR) ; RYU; Hyunseok; (Gyeonggi-do, KR) ; PARK;
Sungjin; (Gyeonggi-do, KR) ; BANG; Jonghyun;
(Gyeonggi-do, KR) ; SHIN; Cheolkyu; (Gyeonggi-do,
KR) ; OH; Jinyoung; (Gyeonggi-do, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Samsung Electronics Co., Ltd. |
Gyeonggi-do |
|
KR |
|
|
Assignee: |
Samsung Electronics Co.,
Ltd.
Gyeonggi-do
KR
|
Family ID: |
70459857 |
Appl. No.: |
16/673297 |
Filed: |
November 4, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04L 1/1887 20130101;
H04L 1/1874 20130101; H04L 1/0057 20130101; H04L 1/1812 20130101;
H04L 1/1685 20130101; H04L 1/1854 20130101 |
International
Class: |
H04L 1/18 20060101
H04L001/18; H04L 1/00 20060101 H04L001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 2, 2018 |
KR |
10-2018-0133896 |
Claims
1. A method of performing communication by a terminal in a wireless
communication system, the method comprising: storing feedback
information for data transmitted from a base station in at least
one hybrid automatic repeat request (HARQ) process; receiving
control information including an indication of feedback triggering;
and transmitting the stored feedback information based on the
indication of the feedback triggering.
2. The method of claim 1, wherein the feedback information is
stored in a hard buffer from among a plurality of buffers including
the hard buffer and a soft buffer.
3. The method of claim 1, further comprising storing at least one
code block (CB) that was successfully decoded among the data
transmitted from the base station.
4. The method of claim 1, further comprising storing at least one
code block (CB) that was successfully decoded and storing a cyclic
redundant check (CRC) of the at least one CB, the at least one CB
being among the data transmitted from the base station.
5. The method of claim 3, wherein storing the feedback information
comprises storing identification information for the at least one
CB that was successfully decoded in a hard buffer and storing
identification information for at least one CB that was not
successfully decoded in a soft buffer.
6. A method of performing communication by a base station in a
wireless communication system, the method comprising: transmitting
data to a terminal; transmitting, to the terminal, control
information including an indication of feedback triggering; and
receiving feedback information for data in at least one hybrid
automatic repeat request (HARQ) process based on the indication of
the feedback triggering, the data being among the transmitted
data.
7. The method of claim 6, wherein the feedback information is
stored in a hard buffer from among a plurality of buffers of the
terminal, the plurality of buffers including the hard buffer and a
soft buffer.
8. A terminal for performing communication in a wireless
communication system, the terminal comprising: at least one buffer;
a transceiver; and a processor coupled with the transceiver and the
at least one buffer, and configured to: store, in the at least one
buffer, feedback information for data transmitted from a base
station in at least one hybrid automatic repeat request (HARQ)
process; control the transceiver to receive control information
including an indication of feedback triggering; and control the
transceiver to transmit the stored feedback information based on
the indication of the feedback triggering.
9. The terminal of claim 8, wherein the feedback information is
stored in a hard buffer from among a plurality of buffers including
the hard buffer and a soft buffer.
10. The terminal of claim 8, wherein the processor is further
configured to store at least one code block (CB) that was
successfully decoded among the data transmitted from the base
station.
11. The terminal of claim 8, wherein the processor is further
configured to store at least one code block (CB) that was
successfully decoded and store a cyclic redundant check (CRC) of
the at least one CB, the at least one CB being among the data
transmitted from the base station.
12. The terminal of claim 10, wherein the processor is further
configured to store identification information for the at least one
CB that was successfully decoded in a hard buffer and
identification information for at least one CB that was not
successfully decoded in a soft buffer.
13. A base station for performing communication in a wireless
communication system, the base station comprising: a transceiver;
and a processor coupled with the transceiver and configured to
control the transceiver to: transmit data to a terminal; transmit,
to the terminal, control information including an indication of
feedback triggering; and receive feedback information for data in
at least one hybrid automatic repeat request (HARQ) process based
on the indication of the feedback triggering, the data being among
the transmitted data.
14. The base station of claim 13, wherein the feedback information
is stored in a hard buffer from among a plurality of buffers of the
terminal, the plurality of buffers including the hard buffer and a
soft buffer.
15. A non-transitory computer-readable recording medium having
recorded thereon a program for executing the method of claim 1 on a
computer.
Description
CROSS-REFERENCE TO RELATED APPLICATION(S)
[0001] This application is based on and claims priority under 35
U.S.C. .sctn. 119 to Korean Patent Application No. 10-2018-0133896,
filed on Nov. 2, 2018, in the Korean Intellectual Property Office,
the disclosure of which is incorporated by reference herein in its
entirety.
BACKGROUND
1. Field
[0002] The disclosure relates generally to a wireless communication
system, and more particularly, to a method and apparatus for
transmitting and receiving data and feedback in a wireless
communication system.
2. Description of the Related Art
[0003] To meet the increasing demand for wireless data traffic due
to the commercialization of 4.sup.th-generation (4G) communication
systems, efforts have been made to develop improved
5.sup.th-generation (5G) communication systems or pre-5G
communication systems. For this reason, 5G communication systems or
pre-5G communication systems are also referred to as
beyond-4G-network communication systems or post-long term evolution
(LTE) systems. For higher data rates, the implementation of 5G
communication systems on ultra-high frequency bands (mmWave), e.g.,
60 GHz, is being considered. In 5G communication systems,
beamforming technologies, massive multi-input multi-output (MIMO)
technologies, full dimensional MIMO (FD-MIMO) technologies, array
antenna technologies, analog beamforming technologies, and
large-scale antenna technologies have been discussed to alleviate
propagation path loss and increasing propagation distances in
ultra-high frequency bands.
[0004] For system network improvement, in 5G communication systems,
technologies such as evolved small cell, advanced small cell, cloud
radio access network (RAN), ultra-dense network, device to device
(D2D) communication, wireless backhaul, moving network, cooperative
communication, coordinated multi-points (CoMPs), and interference
cancellation have been developed. In a 5G system, advanced coding
modulation (ACM) schemes including hybrid frequency-shift keying
(FSK), frequency quadrature amplitude modulation (QAM) (FQAM),
sliding window superposition coding (SWSC), and advanced access
schemes (including filter bank multi carrier (FBMC), non-orthogonal
multiple access (NOMA), and sparse code multiple access (SCMA))
have been developed.
[0005] The Internet is now evolving into the Internet of things
(IoT), where distributed entities, such as objects, exchange and
process information. The Internet of everything (IoE) has also
emerged, which is a combination of IoT technology and big data
processing technology by employing a connection with a cloud
server. In order to implement the IoT, technological elements, such
as sensing technology, wired/wireless communication and network
infrastructure, service interface technology, and security
technology, are required. In this regard, technologies such as
sensor networks, machine to machine (M2M) communication, and
machine-type communication (MTC), have recently been researched for
connection between things. Such an IoT environment may provide
intelligent Internet technology (IT) services that create new value
to human life by collecting and analyzing data generated among
connected things. IoT may be applied to a variety of fields
including smart homes, smart buildings, smart cities, smart or
connected cars, smart grids, health care, smart appliances, and
advanced medical services, by converging and combining existing
information technology and various industries.
[0006] Thus, various attempts have been made to apply 5G
communication systems to IoT networks. For example, 5G
communication, such as sensor networks, M2M, and MTC, has been
implemented by schemes such as beamforming, MIMO, and array
antenna. The application of cloud RAN as a big data processing
technology may also be an example of the convergence of 5G
technology and IoT technology.
[0007] As one of many techniques for satisfying the gradually
increasing demand for large-volume communication, a scheme to
provide multiple connections has been proposed. For example, a
carrier aggregation (CA) scheme of an LTE system may provide
multiple connections through multiple sub-carriers. Thus, a user
may be provided with a service by using more resources. In
addition, through an LTE system, various services such as broadcast
services like multimedia broadcast multicast services (MBMS) may be
provided.
SUMMARY
[0008] The present disclosure has been made to address the
above-mentioned problems and disadvantages, and to provide at least
the advantages described below.
[0009] According to an aspect of the present disclosure, a method
of performing communication by a terminal in a wireless
communication system includes storing feedback information for data
transmitted from a base station (BS) in at least one hybrid
automatic repeat request (HARQ) process; receiving control
information including an indication of feedback triggering; and
transmitting the stored feedback information, based on the
indication of the feedback triggering.
[0010] According to another aspect of the present disclosure, a
method of performing communication by a BS in a wireless
communication system includes transmitting a first set of data to a
terminal; transmitting, to the terminal, control information
including an indication of feedback triggering; and receiving
feedback information for a second set of data in at least one HARQ
process based on the indication of the feedback triggering, the
second set of data being among the first set of transmitted
data.
[0011] According to another aspect of the present disclosure, a
terminal for performing communication in a wireless communication
system includes at least one buffer; a transceiver; and a processor
coupled with the transceiver and the at least one buffer, and
configured to store, in the at least one buffer, feedback
information for data transmitted from a BS in at least one HARQ
process; control the transceiver to receive control information
including an indication of feedback triggering; and control the
transceiver to transmit the stored feedback information, based on
the indication of the feedback triggering.
[0012] According to another aspect of the present disclosure, a
based station (BS) for performing communication in a wireless
communication system includes a transceiver; and a processor
coupled with the transceiver and configured to control the
transceiver to transmit a first set of data to a terminal;
transmit, to the terminal, control information including an
indication of feedback triggering; and receive feedback information
for a second set of data in at least one HARQ process based on the
indication of the feedback triggering, the second set of data being
among the first set of transmitted data.
[0013] According to another aspect of the present disclosure, a
non-transitory computer-readable recording medium having recorded
thereon a program for executing, on a computer, the method of
performing communication by the terminal in the wireless
communication system is provided.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The above and other aspects, features, and advantages of
certain embodiments of the disclosure will be more apparent from
the following description taken in conjunction with the
accompanying drawings, in which:
[0015] FIG. 1 illustrates a basic structure of a time-frequency
domain that is a radio resource domain in which data or a control
channel is transmitted in a downlink (DL) or an uplink (UL) in a
new radio (NR) system, according to an embodiment;
[0016] FIG. 2 illustrates a state where data for services
considered in a 5th-generation (5G) or NR system, such as enhanced
mobile broadband (eMBB), ultra-reliable and low-latency
communications (URLLC), or massive machine type communications
(mMTC), is assigned in frequency-time resources, according to an
embodiment;
[0017] FIG. 3 illustrates a state where data for services
considered in a 5G or NR system, such as eMBB, URLLC, or mMTC, is
assigned in frequency-time resources, according to an
embodiment;
[0018] FIG. 4 illustrates a process in which one transport block is
divided into several code blocks and a cyclic redundant check (CRC)
is added, according to an embodiment;
[0019] FIG. 5 illustrates a state in which synchronization signals
and a physical broadcast channel (PBCH) are mapped in frequency and
time domains in a 3rd-generation partnership project (3GPP) NR
system;
[0020] FIG. 6 is a diagram describing symbols in which one
synchronization signal (SS)/PBCH block is mapped in a slot,
according to an embodiment;
[0021] FIG. 7 is a diagram describing symbols among symbols within
1 ms in which an SS/PBCH block is transmittable, according to an
embodiment;
[0022] FIG. 8 is a diagram describing a slot and symbols among
slots and symbols within 5 ms in which an SS/PBCH block is
transmittable, according to an embodiment;
[0023] FIG. 9 is a diagram describing a method of transmitting data
and transmitting HARQ-acknowledgement (ACK) feedback information
corresponding to the data in an LTE or NR system, according to an
embodiment;
[0024] FIG. 10 is a diagram describing a method, performed by a
user equipment (UE), of feeding back HARQ-ACK information about
data currently processed by a UE in a HARQ process, by transmitting
control information without transmitting data, according to an
embodiment;
[0025] FIG. 11 is a diagram describing a structure of a UE for
receiving and processing DL data, according to an embodiment;
[0026] FIG. 12 is a diagram describing a structure of a UE for
receiving and processing DL data, according to an embodiment;
[0027] FIG. 13 is a diagram describing a method, performed by a UE,
of reducing a HARQ processing time for feeding back HARQ-ACK,
according to an embodiment;
[0028] FIG. 14 is a flowchart illustrating a HARQ-ACK feedback
operation of a UE, according to an embodiment;
[0029] FIG. 15 is a diagram describing a data rate in initial
transmission and retransmission, according to an embodiment;
[0030] FIG. 16 is a diagram describing a HARQ feedback processing
method of a UE, according to an embodiment;
[0031] FIG. 17 is a diagram describing a method, performed by a UE,
of storing an information bit in a buffer based on a code block
(CB) decoding success or failure, according to an embodiment;
[0032] FIG. 18 is a block diagram of a UE, according to an
embodiment; and
[0033] FIG. 19 is a block diagram of a BS, according to an
embodiment.
DETAILED DESCRIPTION
[0034] The disclosure relates to a wireless communication system,
and provides a method and apparatus for transmitting feedback
within a limited time by enabling fast data processing when a UE
receives data and transmits feedback.
[0035] New 5G communication, an NR access technology, has been
designed to allow various services to be freely multiplexed in time
and frequency resources, and thus waveform/numerology and a
reference signal may be dynamically or freely allocated according
to the need of a service. To provide an optimal service to a UE in
wireless communication, optimized data transmission based on
measurement of channel quality and interference quantity is needed,
making accurate channel state measurement indispensable.
[0036] However, unlike 4G communication in which channel and
interference characteristics do not vary greatly with frequency
resources, a 5G channel has channel and interference
characteristics that change largely with a service, requiring a
support for a subset at a frequency resource group (FRG) level to
allow separate measurements. In the NR system, a type of a
supportable service may be categorized into eMBB, mMTC, and URLLC.
The eMBB may be regarded as high-speed transmission of high-volume
data, mMTC may be regarded as minimization of power of the UE and
accesses by multiple UEs, and URLLC may be regarded as a service
aiming at high reliability and low latency. Depending on a type of
a service applied to the UE, different requirements may be
applied.
[0037] Along with the recent on-going research into next-generation
communication systems, various schemes for scheduling communication
with the UE have been discussed. Thus, there is a need for
efficient scheduling and data transmission/reception schemes that
consider characteristics of the next-generation communication
systems.
[0038] As such, in a communication system, a plurality of services
may be provided to a user. A method of providing each of the
plurality of services in the same time period based on the
characteristics and an apparatus capable of using the method may be
required.
[0039] When the embodiments of the disclosure are described,
technical matters that are well known in a technical field of the
disclosure and are not directly related to the disclosure will not
be described. By omitting unnecessary description, the subject
matter of the disclosure can be more clearly described without
being obscured.
[0040] Some elements described herein will be exaggerated, omitted,
or simplified in the attached drawings. The size of each element
does not entirely reflect the actual size of the element. In each
drawing, an identical or corresponding element will be referred to
as an identical reference numeral. A controller may also be
referred to as a processor.
[0041] Throughout the specification, a layer (or a layer apparatus)
may also be referred to as an entity. In other embodiments of the
disclosure, the entity may be a hardware apparatus in the form of a
chip.
[0042] Throughout the disclosure, the expression "at least one of
a, b or c" indicates only a, only b, only c, both a and b, both a
and c, both b and c, all of a, b, and c, or variations thereof.
[0043] Blocks of a flowchart and a combination of flowcharts may be
represented and executed by computer program instructions. The
computer program instructions may be stored in a general-purpose
computer, a special-purpose computer, or a processor of other
programmable data processing devices, such that the instructions
implemented by the computer or the processor of the programmable
data processing device produce a means for performing functions
specified in the flowchart and/or block diagram block or blocks.
The computer program instructions may also be stored in a computer
usable or computer-readable memory that may direct a computer or
other programmable data processing apparatus to function in a
particular manner, such that the instructions stored in the
computer usable or computer-readable memory produce an article of
manufacture including instructions that implement the function
specified in the flowchart and/or block diagram block or blocks.
The computer program instructions may also be loaded onto a
computer or other programmable data processing apparatus to cause a
series of operational steps to be performed on the computer or
other programmable apparatus to produce a computer implemented
process, such that the instructions that execute the computer or
other programmable apparatus may provide steps for implementing the
functions specified in the flowchart and/or block diagram block or
blocks.
[0044] In addition, each block represents a module, segment, or
portion of code, which includes one or more executable instructions
for implementing the specified logical function(s). It should also
be noted that in other implementations, the function(s) noted in
the blocks may occur out of the order indicated. For example, two
blocks shown in succession may, in fact, be executed substantially
concurrently or the blocks may sometimes be executed in the reverse
order, depending on the functionality involved.
[0045] In the current embodiment, the term "unit", as used herein,
denotes a software or hardware component, such as a field
programmable gate array (FPGA) or application specific integrated
circuit (ASIC), which performs certain tasks. However, the meaning
of "unit" is not limited to software or hardware. "Unit" may
advantageously be configured to reside on the addressable storage
medium and configured to reproduce one or more processors. Thus, a
unit may include, by way of example, components, such as software
components, object-oriented software components, class components
and task components, processes, functions, attributes, procedures,
subroutines, segments of program code, drivers, firmware,
microcode, circuitry, data, databases, data structures, tables,
arrays, and variables. The functionality provided in the components
and "units" may be combined into fewer components and "units" or
further separated into additional components and "units". In
addition, components and "units" may be implemented to execute one
or more computer processing units (CPUs) in a device or a secure
multimedia card. In the embodiments of the disclosure, a "unit" may
include one or more processors.
[0046] A wireless communication system has evolved from an initial
one that provides a voice-oriented service to a broadband wireless
communication system that provides a high-speed and high-quality
packet data service, such as 3GPP high speed packet access (HSPA),
LTE or evolved universal terrestrial radio access (E-UTRA),
LTE-Advanced (LTE-A or E-UTRA Evolution), 3GPP2 high rate packet
data (HRPD), ultra mobile broadband (UMB), and the Institute of
Electrical and Electronics Engineers (IEEE) 802.16e. As a 5G
wireless communication system, 5G or NR communication standards
have been established.
[0047] A 5G or NR system as a representative example of a broadband
wireless communication system adopts orthogonal frequency division
multiplexing (OFDM) in a DL and a UL. More specifically,
cyclic-prefix (CP) OFDM is adopted in a DL, and discrete Fourier
transform spreading (DFT-S) OFDM and CP-OFDM are adopted in a UL.
The UL is a radio link through which a UE transmits data or a
control signal to a BS (i.e., a gNodeB), and the DL is a radio link
through which the BS transmits data or a control signal to the UE.
The above-described multiple access scheme separates data or
control information for each user by allocating and operating
time-frequency resources on which the data or the control
information is carried for each user, so that the time-frequency
resources do not overlap each other, that is, so that orthogonality
is realized.
[0048] The 5G or NR system employs a HARQ scheme that retransmits
data in a physical layer when decryption fails in initial
transmission of the data. HARQ refers to a scheme in which when a
receiver fails to accurately decrypt (decode) data, the receiver
transmits information indicating a decoding failure, i.e., a
negative acknowledgement (NACK), to a transmitter to allow the
transmitter to retransmit the data in the physical layer. The
receiver improves data reception performance by combining the data
retransmitted by the transmitter with data that fails to be decoded
previously. When accurately decoding the data, the receiver
transmits information indicating a decoding success, i.e., an ACK,
to the transmitter to allow the transmitter to transmit new
data.
[0049] FIG. 1 illustrates a basic structure of a time-frequency
domain that is a radio resource domain in which data or a control
channel is transmitted in a +DL or a UL in an NR system, according
to an embodiment.
[0050] In FIG. 1, a horizontal axis represents a time domain and a
vertical axis represents a frequency domain. A minimum transmission
unit in the time domain may be an OFDM symbol, in which N.sub.symb
OFDM symbols 1-02 may be gathered to constitute one slot 1-06. The
length of the subframe may be defined as 1.0 millisecond (ms), and
the length of a radio frame 1-14 may be defined as 10 ms. A minimum
transmission unit in the frequency domain may be a subcarrier, and
the transmission bandwidth of the whole system may include
N.sub.RB.sup.DL or N.sub.RB.sup.UL subcarriers 1-04 in total.
[0051] In the time-frequency domain, a basic unit of a resource may
be a resource element (RE) 1-12, and may be indicated as an OFDM
symbol index and a subcarrier index. A resource block (RB) 1-08 or
a physical resource block (PRB) may be defined as N.sub.symb
successive OFDM symbols 1-02 in the time domain or N.sub.RB
successive subcarriers 1-10 in the frequency domain. Accordingly,
one RB 1-08 may be composed of N.sub.symb.times.N.sub.RB REs 1-12.
In general, a minimum transmission unit of data may be the RB unit.
In the NR system, generally, N.sub.symb=14, N.sub.RB=12, and
N.sub.BW and N.sub.RB may be proportional to a bandwidth of a
system transmission band. The data rate may be increased in
proportion to the number of RBs scheduled for the UE.
[0052] In the NR system, for a frequency division duplexing (FDD)
system in which the DL and the UL are discriminated by frequencies
and operated, the DL transmission bandwidth and the UL transmission
bandwidth may differ from each other. The channel bandwidth
indicates an RF bandwidth that corresponds to a system transmission
bandwidth. Table 1 indicates a corresponding relationship between
the system transmission bandwidth defined in the LTE system that is
4G wireless communication prior to the NR system, and the channel
bandwidth. For example, the LTE system having a channel bandwidth
of 10 megahertz (MHz) may have a transmission bandwidth composed of
50 RBs.
TABLE-US-00001 TABLE 1 Channel bandwidth BW.sub.channel [MHz] 1.4 3
5 10 15 20 Transmission bandwidth 6 15 25 50 75 100 configuration
N.sub.RB
[0053] The NR system may support a bandwidth that is broader than
the channel bandwidth of LTE provided in Table 1.
[0054] In the NR system, scheduling information regarding DL data
or UL data may be delivered from the BS to the UE through downlink
control information (DCI). The DCI may be defined according to
various formats. That is, the DCI may be scheduling information (UL
grant) regarding UL data, scheduling information (DL grant)
regarding DL data, or compact DCI having small-size control
information. Additionally, the DCI may apply spatial multiplexing
using multiple antennas, and may be power control. For example, DCI
format 1-1, which is scheduling control information (DL grant)
regarding DL data, may include at least one of the following pieces
of control information:
[0055] Carrier Indicator: indicates a frequency carrier in which a
signal is transmitted;
[0056] DCI Format Indicator: indicates whether a DCI is for a DL or
a UL;
[0057] Bandwidth Part (BWP) Indicator: indicates a BWP in which a
signal is transmitted;
[0058] Frequency Domain Resource Assignment: indicates an RB of a
frequency domain allocated for data transmission. A resource to be
expressed may be determined based on a system bandwidth and a
resource assignment scheme;
[0059] Time Domain Resource Assignment: indicates an OFDM symbol of
a slot in which a data-related channel is to be transmitted;
[0060] VRB-to-PRB Mapping: indicates a scheme for mapping a virtual
RB (VRB) index with a physical RB (PRB) index;
[0061] Modulation and Coding Scheme (MCS): indicates a modulation
scheme and a coding rate used for data transmission. That is, this
may indicate information about whether a modulation scheme is
quadrature phase shift keying (QPSK), 16 QAM, 64QAM, or 256QAM, and
a coding rate value indicating a transport block size (TBS) and
channel coding information;
[0062] Code block Group (CBG) transmission information: indicates
information about a CBG to be transmitted when CBG retransmission
is set;
[0063] HARQ Process Number: indicates a process number of HARQ;
[0064] New Data Indicator: indicates whether transmission is HARQ
initial transmission or retransmission;
[0065] Redundancy version: indicates a redundancy version of HARQ;
and
[0066] Transmit Power Control (TPC) command for Physical Uplink
Control Channel (PUCCH): indicates a TPC command for a PUCCH that
is a UL control channel.
[0067] For the aforementioned PUSCH transmission, time domain
resource assignment may be delivered through information regarding
a slot in which the PUSCH is to be transmitted. A start symbol
position S may be included in the slot, and a symbol number L may
represent the number of symbols to which the PUSCH is mapped. In
the aforementioned descriptions, S may be a relative position from
the start of the slot, L may be the number of consecutive OFDM
symbols, and S and L may be determined from a start and length
indicator value (SLIV) defined as Equation (1) below.
if (L-1).ltoreq.7 then
SLIV=14(L-1)+S
else
SLIV=14(14-L+1)+(14-1-S)
where 0<L.ltoreq.14-S (1)
[0068] In the NR system, for the UE, a table including an SLIV
value, a PUSCH mapping type, and information about a slot in which
a PUSCH is to be transmitted in one row may be generally configured
through RRC configuration. In the following time domain resource
assignment of the DCI, by indicating an index value of the
above-described configured table, the BS may deliver an SLIV value,
a PUSCH mapping type, and information about a slot in which a PUSCH
is to be transmitted to the UE.
[0069] In the NR system, the PUSCH mapping type may be defined as a
type A and a type B. In the PUSCH mapping type A, a first symbol
among demodulation reference signal (DMRS) symbols may be located
in a second or third OFDM symbol of the slot. In the PUSCH mapping
type B, the first symbol among the DMRS symbols may be located in a
first OFDM symbol of a time domain resource assigned for PUSCH
transmission.
[0070] The DCI may be transmitted on a physical downlink control
channel (PDCCH or control information, hereinafter used
interchangeably) through channel coding and modulation.
[0071] Generally, the DCI may be scrambled with a particular radio
network temporary identifier (RNTI) or a terminal identifier,
independently for each terminal, and a CRC is added to the DCI
which is then channel-coded and independently configured as a PDCCH
for transmission. The PDCCH may be transmitted after the PDCCH is
mapped in a control resource set CORESET configured in the UE.
[0072] The DL data may be transmitted on a PDSCH that is a physical
channel for DL data transmission. The PDSCH may be transmitted
after a control channel transmission period, and scheduling
information such as a detailed mapping position and a modulation
scheme in the frequency domain may be determined based on the DCI
transmitted through the PDCCH.
[0073] Using the MCS among the control information of the DCI, the
BS may notify the UE of a modulation scheme applied to the PDSCH to
be transmitted and a size of data to be transmitted (a transport
block size (TBS)). The MCS may be composed of a predetermined
number of bits (i.e., 5 bits or more/less). The TBS may correspond
to the size before a channel coding for error correction is applied
to the data, that is, a transport block (TB), which the BS intends
to transmit.
[0074] The TB may include a medium access control (MAC) header, a
MAC CE, one or more MAC service data units (SDUs), and padding
bits. The TB may indicate the unit of data transmitted down to the
physical layer from the MAC layer, or a MAC protocol data unit
(PDU).
[0075] A modulation scheme supported in the NR system may be QPSK,
16QAM, 64QAM, and 256QAM, and respective modulation orders Qm may
correspond to 2, 4, 6, and 8. For QPSK modulation, 2 bits per
symbol may be transmitted, and for 16QAM, 4 bits per symbol may be
transmitted. Further, 6 bits per symbol may be transmitted for
64QAM, and 8 bits per symbol may be transmitted for 256QAM.
[0076] FIG. 2 illustrates a state where data for services
considered in a 5G or NR system, such as eMBB, URLLC, and mMTC, is
assigned in frequency-time resources, according to an embodiment.
FIG. 3 also illustrates a state where data for services considered
in a 5G or NR system, such as eMBB, URLLC, and mMTC, is assigned in
frequency-time resources, according to an embodiment.
[0077] Referring to FIGS. 2 and 3, a scheme may be seen in which
frequency and time resources are assigned for information
transmission in each system.
[0078] In FIG. 2, data for eMBB, URLLC, and mMTC is assigned in a
total system frequency band 2-00. When URLLC data 2-03, 2-05, and
2-07 are generated and need to be transmitted during assignment and
transmission of eMBB data 2-01 and mMTC data 2-09 in a particular
frequency band, parts with which the eMBB data 2-01 and the mMTC
data 2-09 are already assigned may be emptied or transmission may
not occur, such that the URLLC data 2-03, 2-05, and 2-07 may be
transmitted. The URLLC data 2-03, 2-05, and 2-07 may be assigned to
a part of a resource assigned with the eMBB data 2-01 and
transmitted because a delay time of the URLLC data among the
aforementioned services needs to be reduced. When the URLLC data is
additionally assigned to the eMBB-assigned resource and
transmitted, eMBB data may not be transmitted in the redundant
frequency-time resources, such that transmission performance for
the eMBB data may be degraded. That is, in this case, an eMBB data
transmission failure due to the URLLC assignment may occur.
[0079] In FIG. 3, a total system frequency band 3-00 may be divided
into sub-bands 3-02, 3-04, and 3-06. A service and data may be
transmitted in each divided sub-band 3-02, 3-04, and 3-06. Sub-band
configuration-related information may be previously determined, and
the sub-band configuration-related information may be transmitted
from a BS to a UE through high-layer signaling.
[0080] Sub-band-related information may be arbitrarily divided by
the BS or a network node, such that services may be provided to the
UE without separate transmission of sub-band configuration-related
information to the UE. FIG. 3 shows a state in which a sub-band
3-02 is used for transmission of eMBB data 3-08, a sub-band 3-04 is
used for transmission of URLLC data 3-10, 3-12, and 3-14, and a
sub-band 3-06 is used for transmission of mMTC data 3-16.
[0081] A length of a transmission time interval (TTI) used for
transmission may be shorter than a length of a TTI used for eMBB
mMTC transmission. A response to information related to URLLC may
be transmitted faster than a case with eMBB or mMTC, such that for
URLLC, information may be transmitted and received with low
latency.
[0082] A structure of a physical channel used for each type to
transmit the foregoing three types of services or data may differ.
For example, at least one of a length of a TTI, an assignment unit
of a frequency resource, a structure of a control channel, or a
mapping method of data may be different.
[0083] While three types of services and data have been described
above, more types of services and corresponding data may exist, and
the disclosure is applicable to more types of services and
corresponding data.
[0084] The present disclosure may be applied to a wireless
communication system rather than the NR system.
[0085] FIG. 4 illustrates a process in which one transport block is
divided into several code blocks and a CRC is added, according to
an embodiment.
[0086] Referring to FIG. 4, a CRC 4-03 may be added to an end part
or start part of a TB 4-01 to be transmitted in a UL or DL. The CRC
may have 16 or 24 bits or a pre-fixed bit number, or may have a bit
number variable with a channel condition, and may be used to
determine a channel coding success. The TB 4-01 and the CRC-added
part may be divided into several CBs 4-07, 4-09, 4-11, and 4-13.
The group of CBs are indicated by 4-05. A maximum size for the CB
may be previously defined, and in this case, the last CB 4-13 may
be smaller in size than the other CBs or may be padded with 0, a
random value, or 1 to have the same length as the other CBs. To
each of the CBs 4-07, 4-09, 4-11, and 4-13, CRCs 4-17, 4-19, 4-21,
and 4-23 may be added, as indicated by 4-15. The CRC may have 16 or
24 bits or a pre-fixed bit number, and may be used to determine a
channel coding success.
[0087] The TB 4-01 and a cyclic generator polynomial may be used to
generate the CRC 4-03, and the cyclic generator polynomial may be
defined in various manners. For example, assuming that a cyclic
generator polynomial for a 24-bit CRC is
g.sub.CRC24A(D)=D.sup.24+D.sup.23+D.sup.18+D.sup.17+D.sup.14+D.sup.11+D.s-
up.10+D.sup.7+D.sup.6++D.sup.5+D.sup.4+D.sup.3+D+1
and L=24, then for TB data a.sub.0, a.sub.1, a.sub.2, a.sub.3, . .
. , a.sub.A-1, the CRC p.sub.0, p.sub.1, p.sub.2, p.sub.3, . . . ,
p.sub.L-1 may be determined to be a value having a remainder of 0
after dividing a.sub.0D.sup.A+23+a.sub.1 D.sup.A+22+ . . .
+.sub.A-1D.sup.24+p.sub.0D.sup.23+p.sub.1D.sup.22+ . . .
+p.sub.22D.sup.1+p.sub.23 by g.sub.CRC24A(D).
[0088] Meanwhile, the above description has been made by taking a
CRC length L of 24 as an example, but this is merely an example.
The CRC length L may be determined to be various lengths such as
12, 16, 24, 32, 40, 48, or 64. After the CRC is added to the TB in
the foregoing manner, they may be divided into N CBs 4-07, 4-09,
4-11, and 4-13. The CRCs 4-17, 4-19, 4-21, and 4-23 may be added to
each of the CBs 4-07, 4-09, 4-11, and 4-13, as indicated by 4-15.
To generate the CRC added to the CB, a CRC having a length that is
different from or a cyclic generator polynomial that is different
from one used to generate the CRC is added to the TB. However, the
CRC 4-03 added to the TB 4-01 and the CRCs 4-17, 4-19, 4-21, and
4-23 added to the CBs 4-07, 4-09, 4-11, and 4-13 may be omitted
according to a type of a channel code to be applied to a
corresponding CB. For example, when a low-density parity check
(LDPC) code, instead of a turbo code, is applied to a CB, the CRCs
4-17, 4-19, 4-21, and 4-23 to be inserted to the respective CBs
4-07, 4-09, 4-11, and 4-13 may be omitted. However, even when LDPC
is applied, the CRCs 4-17, 4-19, 4-21, and 4-23 may be added to the
respective CBs 4-07, 4-09, 4-11, and 4-13. In addition, when a
polar code is used, a CRC may be added or omitted.
[0089] As illustrated in FIG. 4, a maximum length of a CB may be
determined according to a type of channel coding to be applied, and
a TB to be transmitted and a CRC added to the TB may be divided
into CBs based on the maximum length of the CB. In an existing LTE
system, a CB-specific CRC is added to a CB, and data bits of the CB
and the CRC are encoded into a channel code to determine coded
bits, in which for the respective coded bits, a previously
agreed-upon rate-matching bit number is determined.
[0090] The BS is an entity that performs resource assignment of the
terminal, and may be at least one of a gNode B (gNB), an eNode B
(eNB), a Node B, a wireless access unit, a BS controller, or a node
on a network. The terminal may include UE, a mobile station (MS), a
cellular phone, a smartphone, a computer, or a multimedia system
capable of performing communication functions.
[0091] A DL may be a wireless transmission path of a signal for
transmission from the BS to the UE, and a UL may mean a wireless
transmission path of a signal for transmission from the UE to the
BS. While embodiments of the disclosure are described by using an
NR system as an example, the disclosure may also be applied to
other communication systems having a similar technical background
or channel form. Also, the disclosure may also be applied to other
communication systems through some modifications within a range
that does not largely depart from the scope of the disclosure based
on the knowledge of one of ordinary skill in the art.
[0092] Conventional physical channels and signals may be used
interchangeably with data or control signals. For example, a
physical downlink shared channel (PDSCH) is a physical channel for
transmitting data, but in the disclosure, a PDSCH may be used as
data.
[0093] High-layer signaling is a method of delivering a signal from
a BS to a UE by using a DL data channel of a physical layer or from
the UE to the BS by using a UL data channel of the physical layer,
and may be mentioned as RRC signaling or a MAC CE.
[0094] In current LTE and NR, the UE may attempt decoding for TB
reception in a physical layer. When any one TB succeeds in
decoding, the UE may deliver an ACK to an upper layer thereof; when
the TB fails in decoding, the UE may deliver a NACK to the upper
layer thereof. To transmit ACK or NACK information back to a
transmission end, the UE may deliver ACK/NACK information from the
upper layer to a physical layer to form feedback information and a
signal.
[0095] The UE may include a reception apparatus operating with
hardware and a reception apparatus operating with software. The UE
may store reception data and a decoding result, i.e., ACK/NACK
information in a software entity. When the UE transmits ACK/NACK
information as feedback, the UE may prepare for transmission by
retrieving ACK/NACK information stored in the software entity to a
hardware entity, during which much processing time is consumed.
[0096] Thus, the disclosure provides a method and apparatus in
which the UE stores an ACK/NACK in the hardware entity and feeds
back the same. Meanwhile, when the UE attempts TB decoding in DL
data transmission, the UE may determine transmission success and
failure by performing decoding for each CB. When the UE fails in
decoding with respect to one CB or TB, the UE may store a log
likelihood ratio (LLR) value for performing decoding or similar
information in a soft buffer. When a corresponding TB is
retransmitted, the stored LLR value may be combined with
retransmitted data for use in decoding. In such implementation,
when the data for retransmission of the TB is received, the data
needs to be combined with the LLR value stored in the soft buffer
and decoding with respect to all CBs needs to be performed again.
That is, even for a CB succeeding in initial transmission, decoding
has to be newly performed. This lengthens a processing time in
retransmission. Therefore, the disclosure provides a method and
apparatus in which information bits of a succeeding CB are stored
to prevent a processing time from increasing even in
retransmission.
[0097] FIG. 5 illustrates a state in which synchronization signals
and a PBCH are mapped in frequency and time domains in a 3GPP NR
system, according to an embodiment. A primary synchronization
signal (PSS) 5-01, a secondary synchronization signal (SSS) 5-03,
and a PBCH 5-05 are mapped to four OFDM symbols, in which the PSS
5-01 and the SSS 5-03 are mapped to twelve RBs and the PBCH 5-05 is
mapped to twenty RBs. FIG. 5 shows a table providing information
for how a frequency band of twenty RBs changes according to
subcarrier spacing (SCS). A resource region in which the PSS, the
SSS, and the PBCH are transmitted may be referred to as an SS/PBCH
block.
[0098] FIG. 6 is a diagram describing symbols in which one SS/PBCH
block is mapped in a slot, according to an embodiment.
[0099] When comparing an LTE system using SS of 15 kilohertz (kHz)
with an NR system using SS of 30 kHz, SS/PBCH blocks 6-11, 6-13,
6-15, and 6-17 of the NR system may be transmitted at positions
6-01, 6-03, 6-05, and 6-07 at which cell-specific reference signals
(CRSs) transmitted at all times in the LTE system may be avoided.
This is intended to allow co-existence of the LTE system and the NR
system in one frequency band.
[0100] FIG. 7 is a diagram describing symbols within 1 ms in which
an SS/PBCH block is transmittable, with respect to SS, according to
an embodiment. FIG. 8 is a diagram describing a slot and symbols
among slots and symbols within 5 ms in which an SS/PBCH block is
transmittable, with respect to SS, according to an embodiment. In a
region where an SS/PBCH block is transmittable, the SS/PBCH block
does not need to be transmitted at all times, and the SS/PBCH block
may be transmitted or may not be transmitted according to selection
of a BS.
[0101] Reception data and a decoding result, i.e., HARQ-ACK
information, may be stored in a hardware entity and the stored
HARQ-ACK information may be fed back.
[0102] FIG. 9 is a diagram describing a method of transmitting data
and transmitting HARQ-ACK feedback information corresponding to the
data in an LTE or NR system, according to an embodiment.
[0103] Referring to FIG. 9, data 9-01, 9-03, and 9-05 corresponding
to HARQ processes 1, 2, and 3 may be respectively transmitted, and
HARQ-ACK information 9-11, 9-13, and 9-15 corresponding to the
respective data 9-01, 9-03, and 9-05 may be fed back. A minimum
processing time for transmitting corresponding HARQ-ACK information
after receiving data by the UE is fixed, such that the UE has to
feed back the HARQ-ACK information as fast as a corresponding
minimum processing time.
[0104] FIG. 10 is a diagram describing a method, performed by a UE,
of feeding back HARQ-ACK information about data currently processed
by a UE in a HARQ process, simply by transmitting control
information without transmitting data, according to an
embodiment.
[0105] Referring to FIG. 10, the BS may transmit to the UE, control
information indicating that HARQ-ACK information regarding data
needs to be fed back or a TB being processed in a current HARQ
process needs to be fed back 10-01.
[0106] The UE having received the control information may feed back
the HARQ-ACK information regarding data being kept or processed in
current HARQ processes to the BS 10-03. For example, when 16 HARQ
processes are configured for the UE for DL data transmission, the
UE may feed back 16-bit or 32-bit HARQ-ACK information to the BS
based on a configuration.
[0107] FIG. 11 is a diagram describing a structure of a UE for
receiving and processing DL data, according to an embodiment.
[0108] Referring to FIG. 11, the UE may roughly include a hardware
entity 11-01 and a software entity 11-03. Division into the
hardware entity 11-01 and the software entity 11-03 may be made by
different blocks or different implementations. The UE may perform
signal reception and processing in the hardware entity 11-01, store
HARQ-ACK feedback information that is reception success or failure
information after performing processing, and deliver the stored
feedback information to an upper layer. Thereafter, in an operation
where the UE feeds back the HARQ-ACK information, the UE may read
the HARQ-ACK information stored in the software entity into the
hardware entity, and generate and transmit a UL signal based on the
HARQ-ACK information. Meanwhile, a time for the UE to read the
HARQ-ACK information stored in the software entity into the
hardware entity is required, increasing a delay time.
[0109] To solve the aforementioned delay issue, the operation of
the embodiment presented in FIG. 12 will be described.
[0110] FIG. 12 is a diagram describing a structure of a UE for
receiving and processing DL data, according to an embodiment.
[0111] Referring to FIG. 12, a receiving UE includes not only a
HARQ-ACK storage space of a software entity 12-03 for delivering
HARQ-ACK information that is a decoding result with respect to
reception data to an upper layer of the UE, but also a buffer 12-05
for storing the HARQ-ACK information in a hardware entity 12-01.
The buffer 12-05 for storing the HARQ-ACK information in the
hardware entity 12-01 may store HARQ-ACK information that is a
decoding result with respect to data corresponding to each HARQ
process.
[0112] FIG. 13 is a diagram describing a method, performed by a UE,
of reducing a HARQ processing time for feeding back a HARQ-ACK,
according to an embodiment.
[0113] As an example, when the UE receives an instruction for
HARQ-ACK transmission for HARQ processes from the BS, the UE may
transmit, using a UL control channel, the HARQ-ACK information that
is stored in the buffer of the hardware entity to feed back the
HARQ-ACK information. As illustrated in FIG. 13, the UE does not
perform an operation of reading HARQ-ACK information stored in the
software entity for HARQ-ACK transmission into the hardware entity,
thereby reducing a HARQ processing time for feeding back the
HARQ-ACK information.
[0114] Descriptions will be made of an ACK/NACK transmission method
for all HARQ processes of the UE through a BS configuration.
[0115] The receiving UE may store all HARQ processes or HARQ-ACK
information for configured HARQ-ACK processes in the buffer 12-05
of the hardware entity 12-01. Thereafter, the UE may prepare for
transmission of a UL control channel for transmission of all stored
HARQ-ACK information. For example, HARQ-ACK information for HARQ
process numbers 1 through 16 may be stored using a bit map, and a
HARQ process number that has not been transmitted or is blank may
be set to a default value (NACK or ACK). The UE may prepare for
transmission of HARQ-ACK information for all HARQ processes or a
configured HARQ process at all times through a UL control channel,
and newly update the HARQ-ACK information based on a decoding
result with respect to reception data. Meanwhile, the BS may
indicate HARQ-ACK information transmission for all HARQ process
numbers stored in the UE by transmitting downlink control
information (DCI) including a HARQ-ACK transmission indicator of 1
bit for all the HARQ process numbers, and the UE may transmit
HARQ-ACK information for all the HARQ process numbers by using a
prepared UL control channel.
[0116] FIG. 14 is a flowchart illustrating a HARQ-ACK feedback
operation of a UE, according to an embodiment.
[0117] Referring to FIG. 14, the UE performs DL data reception and
decoding and stores HARQ-ACK information in a buffer of a hardware
entity in step 1. In step 2, the UE updates HARQ-ACK information
corresponding to a HARQ process number to a bit map, and prepares
for transmission of a UL control channel. When the UE receives a
HARQ-ACK transmission indicator for all HARQ process numbers from
the BS in step 3, the UE transmits a UL control channel including
HARQ-ACK information regarding all the HARQ process numbers in step
4.
[0118] When the UE does not receive the indicator from the BS, the
UE may receive subsequent DL data and then perform a corresponding
operation again. The foregoing operations may be performed each
time when data is received, to update HARQ-ACK transmission
preparation.
[0119] When UL transmission is made from the UE to the BS through
an unlicensed band, the UE may perform a channel access procedure
or listen-before talk (LBT). The UE may access the unlicensed band
when the unlicensed band is determined to be in an idle state as a
result of performing the channel access procedure, and perform
configured signal transmission. A system and device for
transmitting and receiving a signal by using the unlicensed band
has limited channel access, such that HARQ-ACK transmission for all
the HARQ process numbers may be used. When the foregoing disclosure
is applied to the UE using the unlicensed band, an operation of
reading HARQ-ACK information from the software entity into the
hardware entity may not be performed, thus reducing an HARQ
processing time.
[0120] A method will be described in which the UE stores
information bits of a CB succeeding in decoding an initial
transmission and does not perform decoding for a
retransmission.
[0121] FIG. 15 is a diagram for describing a data rate in initial
transmission and retransmission, according to an embodiment.
[0122] An NR system supports partial retransmission in the unit of
a CB group, and considering this point, as illustrated in FIG. 15,
an average or instant data rate in initial transmission and
retransmission may be calculated by dividing a sum of bit numbers
included in CBs actually transmitted or a sum of CB sizes by a
transmission length. More specifically, as indicated by 15-01, in
initial transmission, data is transmitted in a terabyte (TB) size
of Di during a slot of Ti, such that an average data rate may be
calculated as Di/Ti. However, as indicated by 15-03, in
retransmission, partial retransmission may be performed for a CB
failing in initial transmission, such that a sum of CBs to be
transmitted may have a size of Dr (=Di) and for a transmission time
Tr (=Ti), an average data rate may be calculated as Dr/Tr. Herein,
the sum of sizes of CBs actually transmitted in a retransmission,
Dr (=Di), and the transmission time Tr (=Ti) may be reduced
compared to an initial transmission. For example, a slot of 14
symbols may be required to transmit X CBs in an initial
transmission, but a slot of two symbols may be required to transmit
Y (=X) CBs in a retransmission. Thus, when already succeeding CBs
(i.e., successfully transmitted CBs) have to be decoded even though
a small Dr and Tr are required for retransmission as partial
retransmission of CBs, or when the UE uses an existing
implementation, it is difficult to shorten a processing time.
[0123] FIG. 16 is a diagram describing a HARQ feedback processing
method of a UE, according to an embodiment.
[0124] Referring to FIG. 16, an existing implementation method is
indicated by a solid line and an implementation method proposed in
the disclosure is expressed by a dotted line. In step 16-01, when
the UE attempts TB decoding for a received signal, the UE
determines transmission success or failure while performing
decoding for each CB. When the UE fails in decoding with respect to
one CB or TB, the UE stores an LLR value for performing decoding or
similar information in a soft buffer, in step 16-02. When a
corresponding TB is retransmitted, the stored LLR value may be
combined with retransmitted data for use in decoding. In such an
implementation, when the data for retransmission of the TB is
received, the data needs to be combined with the LLR value stored
in the soft buffer and decoding with respect to all CBs needs to be
performed again. That is, even for a CB succeeding in initial
transmission, decoding has to be newly performed.
[0125] As described above, a slot of 14 symbols may be required to
transmit X CBs using a TB size of Di in initial transmission, but a
slot of two symbols may be required to transmit Y (=X) CBs in
retransmission. However, in retransmission, the UE has to perform
decoding again for X CBs when processing Y (=X) CBs, such that the
UE may store HARQ-ACK information in step 16-04 and the same time
is needed to prepare for corresponding HARQ-ACK feedback
transmission as in initial transmission in step 16-05. Thus, the
disclosure provides a method and apparatus for preventing a
retransmission processing time from increasing like in the case of
initial transmission.
[0126] For example, a first method includes storing an information
bit for a CB and a CRC bit succeeding in decoding.
[0127] Additionally or alternatively, a second method includes
storing an information bit for a CB succeeding in decoding, without
CRC.
[0128] The information bit for the CB succeeding in decoding may
mean a hard information bit of 0 or 1 determined after decoding of
soft information, i.e., an LLR value. A method proposed in the
disclosure is indicated by a solid line in FIG. 16. More
specifically, when the UE stores information about a CB succeeding
in decoding in a hard buffer as in step 16-03 of FIG. 16, the UE
does not need to additionally decode a CB succeeding in initial
transmission, in a retransmission stage.
[0129] Meanwhile, the term "hard buffer" in step 16-03 may be
replaced with another term. As in the foregoing example, a slot of
14 symbols may be required to transmit X CBs using a TB size of Di
in initial transmission, but a slot of two symbols may be required
to transmit Y (=X) CBs in retransmission. The UE according to the
disclosure may perform decoding with respect to Y CBs in
combination with an LLR value stored in a soft buffer during
retransmission, and may not perform additional decoding with
respect to (X-Y) CBs because decoding information for (X-Y) CBs is
stored in the hard buffer. Thus, the UE may store HARQ-ACK
information in step 16-04, and a time required for preparation for
PUCCH transmission for the HARQ-ACK information in step 16-05 may
be reduced when compared to initial transmission.
[0130] FIG. 17 is a diagram describing a method, performed by a UE,
of storing an information bit in a buffer based on a CB decoding
success or failure, according to an embodiment.
[0131] The storage space of a buffer may be minimized according to
the method illustrated in FIG. 17. In the method, the UE may
receive a TB and perform decoding for each CB, such that contents
stored in the buffer may be determined according to whether
transmission succeeds or fails. During decoding for each CB, an LLR
value or similar information is stored in the soft buffer in step
17-01 for use in decoding during the next transmission for a CB
failing in decoding. On the other hand, during decoding for each
CB, the UE stores a decoding information bit in the hard buffer (as
in the above-described first and second method) for a CB succeeding
in decoding in step 17-02 to prevent decoding from being performed
additionally during the next transmission.
[0132] A transmitter, a receiver, and a processor of each of the UE
and the BS are illustrated in FIGS. 18 and 19. Transmission and
reception methods of the BS and the UE are illustrated to perform
the data decoding method and the HARQ-ACK feedback storage and
transmission method in the above-described embodiments.
[0133] FIG. 18 is a block diagram of a UE, according to an
embodiment.
[0134] As illustrated in FIG. 18, a UE includes a UE receiver
18-00, a UE transmitter 18-04, and a UE processor 18-02. The UE
receiver 18-00 and the UE transmitter 18-04 are collectively
referred to as a transceiver. The transceiver may transmit and
receive a signal to and from the BS. The signal may include control
information and data.
[0135] The transceiver may include an RF transmitter that
up-converts and amplifies a frequency of a transmission signal and
an RF signal that low-noise-amplifies a received signal and
down-converts a frequency. The transceiver may receive a signal
through a radio channel and output the received signal to the UE
processor 18-02, and transmit a signal output from the UE processor
18-02 through the radio channel.
[0136] The UE processor 18-02 may control a series of processes
such that the UE operates according to the above-described
embodiment of the disclosure. For example, the UE processor 18-02
may control the UE receiver 18-00 to receive data and control
information from the BS, and determine to process a TB included in
the data based on the control information and store and transmit
HARQ-ACK. Thereafter, the UE transmitter 18-04 may deliver feedback
of the data to the BS.
[0137] FIG. 19 is a block diagram of a BS, according to an
embodiment.
[0138] As illustrated in FIG. 19, a BS includes a BS receiver
19-01, a BS transmitter 19-05, and a BS processor 19-03. The BS
receiver 19-01 and the BS transmitter 19-05 will be collectively
referred to as a transceiver. The transceiver may transmit and
receive a signal to and from the UE. The signal may include control
information and data. To this end, the transceiver may include an
RF transmitter that up-converts and amplifies a frequency of a
transmission signal and an RF signal that low-noise-amplifies a
received signal and down-converts a frequency. The transceiver may
receive a signal through a radio channel and output the received
signal to the BS processor 19-03, and transmit a signal output from
the BS processor 19-03 through the radio channel.
[0139] The BS processor 19-03 may control a series of processes
such that the BS operates according to the above-described
embodiment of the disclosure. For example, the BS processor 19-03
may control transmission of a HARQ-ACK feedback. Thereafter, the BS
transmitter 19-05 may transmit control information for transmitting
a HARQ-ACK transmitted in the above-described method, and the BS
receiver 19-01 may receive feedback with respect to the transmitted
data from UEs.
[0140] According to the disclosure, a processing time in data
reception may be shortened, and a feedback preparation time may
also be reduced.
[0141] The embodiments of the disclosure may be practiced in
combination and the disclosure may also be carried out in an LTE
system or a 5G system.
[0142] While the present disclosure has been particularly shown and
described with reference to certain embodiments thereof, it will be
understood by those of ordinary skill in the art that various
changes in form and details may be made therein without departing
from the spirit and scope of the disclosure as defined by the
appended claims and their equivalents
* * * * *