U.S. patent application number 16/379325 was filed with the patent office on 2019-08-01 for method and apparatus for transmitting or receiving uplink signal for terminal supporting short tti in wireless communication sys.
The applicant listed for this patent is LG Electronics Inc.. Invention is credited to Hyunho LEE, Yunjung YI.
Application Number | 20190239196 16/379325 |
Document ID | / |
Family ID | 63678092 |
Filed Date | 2019-08-01 |
United States Patent
Application |
20190239196 |
Kind Code |
A1 |
LEE; Hyunho ; et
al. |
August 1, 2019 |
METHOD AND APPARATUS FOR TRANSMITTING OR RECEIVING UPLINK SIGNAL
FOR TERMINAL SUPPORTING SHORT TTI IN WIRELESS COMMUNICATION
SYSTEM
Abstract
An uplink transmitting method for a user equipment (UE) for
supporting a short transmission time interval (TTI) in a wireless
communication includes receiving downlink control information
including uplink grant, and when a transmitting timing of an uplink
signal corresponding to the uplink grant and a transmission timing
of a semi-persistent (SPS) uplink signal overlap with each other,
if a TTI length of a first channel in which the uplink signal
corresponding to the uplink grant is to be transmitted is longer
than a TTI length of a second channel in which the SPS uplink
signal is to be transmitted, performing uplink signal transmission
only on the second channel of the first channel and the second
channel at the transmission timing.
Inventors: |
LEE; Hyunho; (Seoul, KR)
; YI; Yunjung; (Seoul, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
LG Electronics Inc. |
Seoul |
|
KR |
|
|
Family ID: |
63678092 |
Appl. No.: |
16/379325 |
Filed: |
April 9, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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16065682 |
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PCT/KR2018/003858 |
Apr 2, 2018 |
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16379325 |
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62643718 |
Mar 15, 2018 |
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62636162 |
Feb 28, 2018 |
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62617575 |
Jan 15, 2018 |
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62586128 |
Nov 14, 2017 |
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62566347 |
Sep 30, 2017 |
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62480368 |
Apr 1, 2017 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04L 5/00 20130101; H04L
1/1861 20130101; H04L 1/1854 20130101; H04L 5/0044 20130101; H04L
5/0053 20130101; H04W 72/14 20130101; H04L 1/1858 20130101; H04L
5/0055 20130101; H04W 72/0413 20130101; H04L 1/1671 20130101; H04L
1/1864 20130101; H04W 72/042 20130101; H04W 72/1268 20130101; H04L
1/18 20130101 |
International
Class: |
H04W 72/04 20060101
H04W072/04; H04W 72/14 20060101 H04W072/14; H04L 1/18 20060101
H04L001/18 |
Claims
1. A method for transmitting an uplink signal by a user equipment
supporting uplink transmissions having different transmission time
interval (TTI) lengths in a wireless communication, the method
comprising: receiving configuration information indicating a
resource set for a semi-persistently scheduled (SPS) uplink
transmission; and performing the SPS uplink transmission in the
indicated resource set, wherein, when the SPS uplink transmission
overlaps in time with an uplink transmission scheduled by uplink
grant downlink control information (DCI) and the SPS uplink
transmission has a shorter TTI length than the uplink transmission
scheduled by the uplink grant DCI, the uplink transmission
scheduled by the uplink grant DCI is dropped.
2. The method according to claim 1, wherein the uplink transmission
scheduled by the uplink grant DCI has a length corresponding to a
subframe length.
3. The method according to claim 1, wherein the SPS uplink
transmission has a length equal to or smaller than a slot
length.
4. The method according to claim 1, wherein the SPS uplink
transmission is performed through a physical uplink shared channel
(PUSCH).
5. The method according to claim 1, wherein the uplink grant DCI is
received through a physical downlink control channel (PDCCH).
6. The method according to claim 1, wherein uplink control
information is transmitted through the SPS uplink transmission.
7. The method according to claim 6, wherein the uplink control
information includes hybrid automatic repeat request
acknowledgement (HARQ-ACK) information.
8. A user equipment for transmitting an uplink signal in a wireless
communication system, the user equipment supporting uplink
transmissions having different transmission time interval (TTI)
lengths and comprising: a receiver and a transmitter; and a
processor operatively connected to the receiver and the transmitter
and configured to: control the receiver to receive configuration
information indicating a resource set for a semi-persistently
scheduled (SPS) uplink transmission, and control the transmitter to
perform the SPS uplink transmission in the indicated resource set,
wherein, when the SPS uplink transmission overlaps in time with an
uplink transmission scheduled by uplink grant downlink control
information (DCI) and the SPS uplink transmission has a shorter TTI
length than the uplink transmission scheduled by the uplink grant
DCI, the uplink transmission scheduled by the uplink grant DCI is
dropped.
9. The user equipment according to claim 8, wherein the uplink
transmission scheduled by the uplink grant DCI has a length
corresponding to a subframe length.
10. The user equipment according to claim 8, wherein the SPS uplink
transmission has a length equal to or smaller than a slot
length.
11. The user equipment according to claim 8, wherein the SPS uplink
transmission is performed through a physical uplink shared channel
(PUSCH).
12. The user equipment according to claim 8, wherein the uplink
grant DCI is received through a physical downlink control channel
(PDCCH).
13. The user equipment according to claim 8, wherein uplink control
information is transmitted through the SPS uplink transmission.
14. The user equipment according to claim 13, wherein the uplink
control information includes hybrid automatic repeat request
acknowledgement (HARQ-ACK) information.
15. A processor for a wireless communication device supporting
uplink transmissions having different transmission time interval
(TTI) lengths, wherein the processor is configured to control the
wireless communication device to perform: receiving configuration
information indicating a resource set for a semi-persistently
scheduled (SPS) uplink transmission; and performing the SPS uplink
transmission in the indicated resource set, wherein, when the SPS
uplink transmission overlaps in time with an uplink transmission
scheduled by uplink grant downlink control information (DCI) and
the SPS uplink transmission has a shorter TTI length than the
uplink transmission scheduled by the uplink grant DCI, the uplink
transmission scheduled by the uplink grant DCI is dropped.
16. The processor according to claim 15, wherein the uplink
transmission scheduled by the uplink grant DCI has a length
corresponding to a subframe length.
17. The processor according to claim 15, wherein the SPS uplink
transmission has a length equal to or smaller than a slot
length.
18. The processor according to claim 15, wherein the SPS uplink
transmission is performed through a physical uplink shared channel
(PUSCH).
19. The processor according to claim 15, wherein the uplink grant
DCI is received through a physical downlink control channel
(PDCCH).
20. The processor according to claim 15, wherein uplink control
information is transmitted through the SPS uplink transmission.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 16/065,682, filed on Jun. 22, 2018, which is a National Stage
application under 35 U.S.C. .sctn. 371 of International Application
No. PCT/KR2018/003858, filed on Apr. 2, 2018, which claims the
benefit of U.S. Provisional Application No. 62/643,718, filed on
Mar. 15, 2018, U.S. Provisional Application No. 62/636,162, filed
on Feb. 28, 2018, U.S. Provisional Application No. 62/617,575,
filed on Jan. 15, 2018, U.S. Provisional Application No.
62/586,128, filed on Nov. 14, 2017, U.S. Provisional Application
No. 62/566,347, filed on Sep. 30, 2017, and U.S. Provisional
Application No. 62/480,368, filed on Apr. 1, 2017. The disclosures
of the prior applications are incorporated by reference in their
entirety.
TECHNICAL FIELD
[0002] The present invention relates to a wireless communication
system, and more particularly, a method and apparatus for
supporting a plurality of transmission time intervals, a plurality
of subcarrier spacing, or a plurality of processing times.
BACKGROUND ART
[0003] Latency of packet data is one of important performance
metrics and one of important objectives in designs of a
next-generation mobile communication system as well as LTE, a
so-called new RAT, is to reduce latency and to provide rapider
Internet access to an end user.
[0004] The present invention proposes the feature related to a
method of transmitting or receiving an uplink (UL) signal in a
wireless communication system for supporting reduction in
latency.
DISCLOSURE
Technical Problem
[0005] An object of the present invention devised to solve the
problem lies in an uplink (UL) transmission operation of a user
equipment (UE) for supporting a plurality of transmission time
interval, a plurality of subcarrier spacing, or a plurality of
processing times or a UL receiving operation of an eNB that
communicates with the UE.
[0006] It is to be understood that both the foregoing general
description and the following detailed description of the present
invention are exemplary and explanatory and are intended to provide
further explanation of the invention as claimed.
Technical Solution
[0007] The object of the present invention can be achieved by
providing an uplink transmitting method for a terminal for
supporting a short transmission time interval (TTI) length in a
wireless communication, the method including receiving downlink
control information including uplink grant, and when a transmitting
timing of an uplink signal corresponding to the uplink grant and a
transmission timing of a semi-persistent (SPS) uplink signal
overlap with each other, and when a TTI length of a first channel
on which the uplink signal corresponding to the uplink grant is to
be transmitted is longer than a TTI length of a second channel on
which the SPS uplink signal is to be transmitted, performing uplink
signal transmission only on the second channel of the first channel
and the second channel at the transmission timing.
[0008] Additionally or alternatively, the method may further
include when second downlink control information including second
uplink grant for scheduling transmission of a physical uplink
shared channel (PUSCH) with a shorter length than the TTI length of
the first channel is received during a time period from a next
subframe ("subframe #n+1") of a subframe in which the downlink
control information is received to a subframe ("subframe #n+k"), in
which the uplink signal corresponding to the uplink grant is to be
transmitted, transmitting the uplink signal corresponding to the
uplink grant on a physical uplink control channel (PUCCH) in the
subframe #n+k.
[0009] Additionally or alternatively, the method may further
include, when second downlink control information including second
uplink grant for scheduling transmission of a physical uplink
shared channel (PUSCH) with a shorter length than the TTI length of
the first channel is received during a time period from a next
subframe ("subframe #n+1") of a subframe in which the downlink
control information is received to a subframe ("subframe #n+k"), in
which the uplink signal corresponding to the uplink grant is to be
transmitted, transmitting the uplink signal corresponding to the
uplink grant on a shortened PUCCH (SPUCCH) in an n.sup.th TTI with
a shorter length than the TTI length of the first channel in the
subframe #n+k, where n is preconfigured.
[0010] Additionally or alternatively, the method may further
include, when second downlink control information including second
uplink grant for scheduling transmission of a physical uplink
shared channel (PUSCH) with a shorter length than the TTI length of
the first channel is received during a time period from a next
subframe ("subframe #n+1") of a subframe in which the downlink
control information is received to a subframe ("subframe #n+k"), in
which the uplink signal corresponding to the uplink grant is to be
transmitted, transmitting the uplink signal corresponding to the
uplink grant on a first channel that does not include data in the
subframe #n+k.
[0011] Additionally or alternatively, transmission power may be
used only in a symbol to which the uplink signal is mapped in the
subframe #n+k.
[0012] Additionally or alternatively, transmission power may be
used only in a resource block to which the uplink signal is mapped
among resource blocks indicated by the downlink control information
in the subframe #n+k.
[0013] In another aspect of the present invention, provided herein
is a terminal for transmitting an uplink signal with a short
transmission time interval (TTI) length in a wireless communication
system, including a receiver and a transmitter, and a processor
that controls the receiver and the transmitter, wherein the
processor may receive downlink control information including uplink
grant and configured to, when a transmitting timing of an uplink
signal corresponding to the uplink grant and a transmission timing
of a semi-persistent (SPS) uplink signal overlap with each other,
and when a TTI length of a first channel on which the uplink signal
corresponding to the uplink grant is to be transmitted is longer
than a TTI length of a second channel on which the SPS uplink
signal is to be transmitted, perform uplink signal transmission
only on the second channel of the first channel and the second
channel at the transmission timing.
[0014] Additionally or alternatively, when second downlink control
information including second uplink grant for scheduling
transmission of a physical uplink shared channel (PUSCH) with a
shorter length than the TTI length of the first channel is received
during a time period from a next subframe ("subframe #n+1") of a
subframe in which the downlink control information is received to a
subframe ("subframe #n+k") in which the uplink signal corresponding
to the uplink grant is to be transmitted, the processor may
transmit the uplink signal corresponding to the uplink grant on a
physical uplink control channel (PUCCH) in the subframe #n+k.
[0015] Additionally or alternatively, when second downlink control
information including second uplink grant for scheduling
transmission of a physical uplink shared channel (PUSCH) with a
shorter length than the TTI length of the first channel is received
during a time period from a next subframe ("subframe #n+1") of a
subframe in which the downlink control information is received to a
subframe ("subframe #n+k") in which the uplink signal corresponding
to the uplink grant is to be transmitted, the processor may
transmit the uplink signal corresponding to the uplink grant on a
shortened PUCCH (SPUCCH) in an n.sup.th TTI with a shorter length
than the TTI length of the first channel in the subframe #n+k,
where n is preconfigured.
[0016] Additionally or alternatively, when second downlink control
information including second uplink grant for scheduling
transmission of a physical uplink shared channel (PUSCH) with a
shorter length than the TTI length of the first channel is received
during a time period from a next subframe ("subframe #n+1") of a
subframe in which the downlink control information is received to a
subframe ("subframe #n+k") in which the uplink signal corresponding
to the uplink grant is to be transmitted, the processor may
transmit the uplink signal corresponding to the uplink grant on a
first channel that does not include data in the subframe #n+k.
[0017] Additionally or alternatively, transmission power may be
used only in a symbol to which the uplink signal is mapped in the
subframe #n+k.
[0018] Additionally or alternatively, transmission power may be
used only in a resource block to which the uplink single is mapped
among resource blocks indicated by the downlink control information
in the subframe #n+k.
[0019] It is to be understood that both the foregoing general
description and the following detailed description of the present
invention are exemplary and explanatory and are intended to provide
further explanation of the invention as claimed.
Advantageous Effects
[0020] According to embodiments of the present invention, uplink
(UL) transmission of a user equipment (UE) for supporting a
plurality of transmission time interval (TTI) lengths, a plurality
of subcarrier spacing, or a plurality of processing times may be
effectively performed.
[0021] It will be appreciated by persons skilled in the art that
that the effects that could be achieved with the present invention
are not limited to what has been particularly described hereinabove
and other advantages of the present invention will be more clearly
understood from the following detailed description taken in
conjunction with the accompanying drawings.
DESCRIPTION OF DRAWINGS
[0022] The accompanying drawings, which are included to provide a
further understanding of the invention, illustrate embodiments of
the invention and together with the description serve to explain
the principle of the invention.
[0023] In the drawings:
[0024] FIG. 1 is a diagram showing an example of a radio frame
structure used in a wireless communication system;
[0025] FIG. 2 is a diagram showing an example of a downlink/uplink
(DL/UL) slot structure in a wireless communication system;
[0026] FIG. 3 is a diagram showing an example of a DL subframe
structure used in a 3GPP LTE/LTE-A system;
[0027] FIG. 4 is a diagram showing an example of a UL subframe
structure used in a 3GPP LTE/LTE-A system;
[0028] FIG. 5 is a diagram showing reduction in a TTI length
according to reduction in user plane latency;
[0029] FIG. 6 is a diagram showing an example in which a plurality
of short TTIs is set in one subframe;
[0030] FIG. 7 is a diagram showing a DL subframe structure
including a short TTI with a plurality of lengths (symbol
numbers);
[0031] FIG. 8 is a diagram showing a DL subframe structure
including a short TTI including two or three symbols; and
[0032] FIG. 9 is a block diagram showing an apparatus for embodying
embodiment(s) of the present invention.
BEST MODE
[0033] Reference will now be made in detail to the preferred
embodiments of the present invention, examples of which are
illustrated in the accompanying drawings. The accompanying drawings
illustrate exemplary embodiments of the present invention and
provide a more detailed description of the present invention.
However, the scope of the present invention should not be limited
thereto.
[0034] In some cases, to prevent the concept of the present
invention from being ambiguous, structures and apparatuses of the
known art will be omitted, or will be shown in the form of a block
diagram based on main functions of each structure and apparatus.
Also, wherever possible, the same reference numbers will be used
throughout the drawings and the specification to refer to the same
or like parts.
[0035] In the present invention, a user equipment (UE) is fixed or
mobile. The UE is a device that transmits and receives user data
and/or control information by communicating with a base station
(BS). The term `UE` may be replaced with `terminal equipment`,
`Mobile Station (MS)`, `Mobile Terminal (MT)`, `User Terminal
(UT)`, `Subscriber Station (SS)`, `wireless device`, `Personal
Digital Assistant (PDA)`, `wireless modem`, `handheld device`, etc.
A BS is typically a fixed station that communicates with a UE
and/or another BS. The BS exchanges data and control information
with a UE and another BS. The term `BS` may be replaced with
`Advanced Base Station (ABS)`, `Node B`, `evolved-Node B (eNB)`,
`Base Transceiver System (BTS)`, `Access Point (AP)`, `Processing
Server (PS)`, etc. In the following description, BS is commonly
called eNB.
[0036] In the present invention, a node refers to a fixed point
capable of transmitting/receiving a radio signal to/from a UE by
communication with the UE. Various eNBs can be used as nodes. For
example, a node can be a BS, NB, eNB, pico-cell eNB (PeNB), home
eNB (HeNB), relay, repeater, etc. Furthermore, a node may not be an
eNB. For example, a node can be a radio remote head (RRH) or a
radio remote unit (RRU). The RRH and RRU have power levels lower
than that of the eNB. Since the RRH or RRU (referred to as RRH/RRU
hereinafter) is connected to an eNB through a dedicated line such
as an optical cable in general, cooperative communication according
to RRH/RRU and eNB can be smoothly performed compared to
cooperative communication according to eNBs connected through a
wireless link. At least one antenna is installed per node. An
antenna may refer to an antenna port, a virtual antenna or an
antenna group. A node may also be called a point. Unlike a
conventional centralized antenna system (CAS) (i.e. single node
system) in which antennas are concentrated in an eNB and controlled
an eNB controller, plural nodes are spaced apart at a predetermined
distance or longer in a multi-node system. The plural nodes can be
managed by one or more eNBs or eNB controllers that control
operations of the nodes or schedule data to be transmitted/received
through the nodes. Each node may be connected to an eNB or eNB
controller managing the corresponding node via a cable or a
dedicated line. In the multi-node system, the same cell identity
(ID) or different cell IDs may be used for signal
transmission/reception through plural nodes. When plural nodes have
the same cell ID, each of the plural nodes operates as an antenna
group of a cell. If nodes have different cell IDs in the multi-node
system, the multi-node system can be regarded as a multi-cell
(e.g., macro-cell/femto-cell/pico-cell) system. When multiple cells
respectively configured by plural nodes are overlaid according to
coverage, a network configured by multiple cells is called a
multi-tier network. The cell ID of the RRH/RRU may be identical to
or different from the cell ID of an eNB. When the RRH/RRU and eNB
use different cell IDs, both the RRH/RRU and eNB operate as
independent eNBs.
[0037] In a multi-node system according to the present invention,
which will be described below, one or more eNBs or eNB controllers
connected to plural nodes can control the plural nodes such that
signals are simultaneously transmitted to or received from a UE
through some or all nodes. While there is a difference between
multi-node systems according to the nature of each node and
implementation form of each node, multi-node systems are
discriminated from single node systems (e.g. CAS, conventional MIMO
systems, conventional relay systems, conventional repeater systems,
etc.) since a plurality of nodes provides communication services to
a UE in a predetermined time-frequency resource. Accordingly,
embodiments of the present invention with respect to a method of
performing coordinated data transmission using some or all nodes
can be applied to various types of multi-node systems. For example,
a node refers to an antenna group spaced apart from another node by
a predetermined distance or more, in general. However, embodiments
of the present invention, which will be described below, can even
be applied to a case in which a node refers to an arbitrary antenna
group irrespective of node interval. In the case of an eNB
including an X-pole (cross polarized) antenna, for example, the
embodiments of the preset invention are applicable on the
assumption that the eNB controls a node composed of an H-pole
antenna and a V-pole antenna.
[0038] A communication scheme through which signals are
transmitted/received via plural transmit (Tx)/receive (Rx) nodes,
signals are transmitted/received via at least one node selected
from plural Tx/Rx nodes, or a node transmitting a downlink signal
is discriminated from a node transmitting an uplink signal is
called multi-eNB MIMO or CoMP (Coordinated Multi-Point Tx/Rx).
Coordinated transmission schemes from among CoMP communication
schemes can be categorized into JP (Joint Processing) and
scheduling coordination. The former may be divided into JT (Joint
Transmission)/JR (Joint Reception) and DPS (Dynamic Point
Selection) and the latter may be divided into CS (Coordinated
Scheduling) and CB (Coordinated Beamforming). DPS may be called DCS
(Dynamic Cell Selection). When JP is performed, more various
communication environments can be generated, compared to other CoMP
schemes. JT refers to a communication scheme by which plural nodes
transmit the same stream to a UE and JR refers to a communication
scheme by which plural nodes receive the same stream from the UE.
The UE/eNB combine signals received from the plural nodes to
restore the stream. In the case of JT/JR, signal transmission
reliability can be improved according to transmit diversity since
the same stream is transmitted from/to plural nodes. DPS refers to
a communication scheme by which a signal is transmitted/received
through a node selected from plural nodes according to a specific
rule. In the case of DPS, signal transmission reliability can be
improved because a node having a good channel state between the
node and a UE is selected as a communication node.
[0039] In the present invention, a cell refers to a specific
geographical area in which one or more nodes provide communication
services. Accordingly, communication with a specific cell may mean
communication with an eNB or a node providing communication
services to the specific cell. A downlink/uplink signal of a
specific cell refers to a downlink/uplink signal from/to an eNB or
a node providing communication services to the specific cell. A
cell providing uplink/downlink communication services to a UE is
called a serving cell. Furthermore, channel status/quality of a
specific cell refers to channel status/quality of a channel or a
communication link generated between an eNB or a node providing
communication services to the specific cell and a UE. In 3GPP LTE-A
systems, a UE can measure downlink channel state from a specific
node using one or more CSI-RSs (Channel State Information Reference
Signals) transmitted through antenna port(s) of the specific node
on a CSI-RS resource allocated to the specific node. In general,
neighboring nodes transmit CSI-RS resources on orthogonal CSI-RS
resources. When CSI-RS resources are orthogonal, this means that
the CSI-RS resources have different subframe configurations and/or
CSI-RS sequences which specify subframes to which CSI-RSs are
allocated according to CSI-RS resource configurations, subframe
offsets and transmission periods, etc. which specify symbols and
subcarriers carrying the CSI RSs.
[0040] In the present invention, PDCCH (Physical Downlink Control
Channel)/PCFICH (Physical Control Format Indicator Channel)/PHICH
(Physical Hybrid automatic repeat request Indicator Channel)/PDSCH
(Physical Downlink Shared Channel) refer to a set of time-frequency
resources or resource elements respectively carrying DCI (Downlink
Control Information)/CFI (Control Format Indicator)/downlink
ACK/NACK (Acknowledgement/Negative ACK)/downlink data. In addition,
PUCCH (Physical Uplink Control Channel)/PUSCH (Physical Uplink
Shared Channel)/PRACH (Physical Random Access Channel) refer to
sets of time-frequency resources or resource elements respectively
carrying UCI (Uplink Control Information)/uplink data/random access
signals. In the present invention, a time-frequency resource or a
resource element (RE), which is allocated to or belongs to
PDCCH/PCFICH/PHICH/PDSCH/PUCCH/PUSCH/PRACH, is referred to as a
PDCCH/PCFICH/PHICH/PDSCH/PUCCH/PUSCH/PRACH RE or
PDCCH/PCFICH/PHICH/PDSCH/PUCCH/PUSCH/PRACH resource. In the
following description, transmission of PUCCH/PUSCH/PRACH by a UE is
equivalent to transmission of uplink control information/uplink
data/random access signal through or on PUCCH/PUSCH/PRACH.
Furthermore, transmission of PDCCH/PCFICH/PHICH/PDSCH by an eNB is
equivalent to transmission of downlink data/control information
through or on PDCCH/PCFICH/PHICH/PDSCH.
[0041] FIG. 1 illustrates an exemplary radio frame structure used
in a wireless communication system. FIG. 1(a) illustrates a frame
structure for frequency division duplex (FDD) used in 3GPP
LTE/LTE-A and FIG. 1(b) illustrates a frame structure for time
division duplex (TDD) used in 3GPP LTE/LTE-A.
[0042] Referring to FIG. 1, a radio frame used in 3GPP LTE/LTE-A
has a length of 10 ms (307200 Ts) and includes 10 subframes in
equal size. The 10 subframes in the radio frame may be numbered.
Here, Ts denotes sampling time and is represented as Ts=1/(2048*15
kHz). Each subframe has a length of 1 ms and includes two slots. 20
slots in the radio frame can be sequentially numbered from 0 to 19.
Each slot has a length of 0.5 ms. A time for transmitting a
subframe is defined as a transmission time interval (TTI). Time
resources can be discriminated by a radio frame number (or radio
frame index), subframe number (or subframe index) and a slot number
(or slot index).
[0043] The radio frame can be configured differently according to
duplex mode. Downlink transmission is discriminated from uplink
transmission by frequency in FDD mode, and thus the radio frame
includes only one of a downlink subframe and an uplink subframe in
a specific frequency band. In TDD mode, downlink transmission is
discriminated from uplink transmission by time, and thus the radio
frame includes both a downlink subframe and an uplink subframe in a
specific frequency band.
[0044] Table 1 shows DL-UL configurations of subframes in a radio
frame in the TDD mode.
TABLE-US-00001 TABLE 1 Downlink- to-Uplink Switch- DL-UL point
Subframe number configuration periodicity 0 1 2 3 4 5 6 7 8 9 0 5
ms D S U U U D S U U U 1 5 ms D S U U D D S U U D 2 5 ms D S U D D
D S U D D 3 10 ms D S U U U D D D D D 4 10 ms D S U U D D D D D D 5
10 ms D S U D D D D D D D 6 5 ms D S U U U D S U U D
[0045] In Table 1, D denotes a downlink subframe, U denotes an
uplink subframe and S denotes a special subframe. The special
subframe includes three fields of DwPTS (Downlink Pilot TimeSlot),
GP (Guard Period), and UpPTS (Uplink Pilot TimeSlot). DwPTS is a
period reserved for downlink transmission and UpPTS is a period
reserved for uplink transmission. Table 2 shows special subframe
configuration.
TABLE-US-00002 TABLE 2 Normal cyclic prefix in downlink Extended
cyclic prefix in downlink UpPTS UpPTS Extended Normal Extended
Special Normal cyclic cyclic cyclic subframe cyclic prefix prefix
in prefix in prefix in configuration DwPTS in uplink uplink DwPTS
uplink uplink 0 6592 T.sub.s 2192 T.sub.s 2560 T.sub.s 7680 T.sub.s
2192 T.sub.s 2560 T.sub.s 1 19760 T.sub.s 20480 T.sub.s 2 21952
T.sub.s 23040 T.sub.s 3 24144 T.sub.s 25600 T.sub.s 4 26336 T.sub.s
7680 T.sub.s 4384 T.sub.s 5120 T.sub.s 5 6592 T.sub.s 4384 T.sub.s
5120 T.sub.s 20480 T.sub.s 6 19760 T.sub.s 23040 T.sub.s 7 21952
T.sub.s 12800 T.sub.s 8 24144 T.sub.s -- -- -- 9 13168 T.sub.s --
-- --
[0046] FIG. 2 illustrates an exemplary downlink/uplink slot
structure in a wireless communication system. Particularly, FIG. 2
illustrates a resource grid structure in 3GPP LTE/LTE-A. A resource
grid is present per antenna port.
[0047] Referring to FIG. 2, a slot includes a plurality of OFDM
(Orthogonal Frequency Division Multiplexing) symbols in the time
domain and a plurality of resource blocks (RBs) in the frequency
domain. An OFDM symbol may refer to a symbol period. A signal
transmitted in each slot may be represented by a resource grid
composed of N.sub.RB.sup.DL/UL*N.sub.sc.sup.RB subcarriers and
N.sub.symb.sup.DL/UL OFDM symbols. Here, N.sub.RB.sup.DL denotes
the number of RBs in a downlink slot and N.sub.RB.sup.UL denotes
the number of RBs in an uplink slot. N.sub.RB.sup.DL and
N.sub.RB.sup.UL respectively depend on a DL transmission bandwidth
and a UL transmission bandwidth. N.sub.symb.sup.UL denotes the
number of OFDM symbols in the downlink slot and N.sub.symb.sup.UL
denotes the number of OFDM symbols in the uplink slot. In addition,
N.sub.sc.sup.RB denotes the number of subcarriers constructing one
RB.
[0048] An OFDM symbol may be called an SC-FDM (Single Carrier
Frequency Division Multiplexing) symbol according to multiple
access scheme. The number of OFDM symbols included in a slot may
depend on a channel bandwidth and the length of a cyclic prefix
(CP). For example, a slot includes 7 OFDM symbols in the case of
normal CP and 6 OFDM symbols in the case of extended CP. While FIG.
2 illustrates a subframe in which a slot includes 7 OFDM symbols
for convenience, embodiments of the present invention can be
equally applied to subframes having different numbers of OFDM
symbols. Referring to FIG. 2, each OFDM symbol includes
N.sub.RB.sup.DL/UL*N.sub.sc.sup.RB subcarriers in the frequency
domain. Subcarrier types can be classified into a data subcarrier
for data transmission, a reference signal subcarrier for reference
signal transmission, and null subcarriers for a guard band and a
direct current (DC) component. The null subcarrier for a DC
component is a subcarrier remaining unused and is mapped to a
carrier frequency (f0) during OFDM signal generation or frequency
up-conversion. The carrier frequency is also called a center
frequency.
[0049] An RB is defined by N.sub.symb.sup.DL/UL(e.g., 7)
consecutive OFDM symbols in the time domain and N.sub.sc.sup.RB
(e.g., 12) consecutive subcarriers in the frequency domain. For
reference, a resource composed by an OFDM symbol and a subcarrier
is called a resource element (RE) or a tone. Accordingly, an RB is
composed of N.sub.symb.sup.DL/UL*N.sub.sc.sup.RB REs. Each RE in a
resource grid can be uniquely defined by an index pair (k, l) in a
slot. Here, k is an index in the range of 0 to
N.sub.symb.sup.DL/UL*N.sub.sc.sup.RB-1 in the frequency domain and
l is an index in the range of 0 to N.sub.symb.sup.DL/UL-1.
[0050] Two RBs that occupy N.sub.sc.sup.RB consecutive subcarriers
in a subframe and respectively disposed in two slots of the
subframe are called a physical resource block (PRB) pair. Two RBs
constituting a PRB pair have the same PRB number (or PRB index). A
virtual resource block (VRB) is a logical resource allocation unit
for resource allocation. The VRB has the same size as that of the
PRB. The VRB may be divided into a localized VRB and a distributed
VRB depending on a mapping scheme of VRB into PRB. The localized
VRBs are mapped into the PRBs, whereby VRB number (VRB index)
corresponds to PRB number. That is, nPRB=nVRB is obtained. Numbers
are given to the localized VRBs from 0 to N.sub.VRB.sup.DL-1, and
N.sub.VRB.sup.DL=N.sub.RB.sup.DL is obtained. Accordingly,
according to the localized mapping scheme, the VRBs having the same
VRB number are mapped into the PRBs having the same PRB number at
the first slot and the second slot. On the other hand, the
distributed VRBs are mapped into the PRBs through interleaving.
Accordingly, the VRBs having the same VRB number may be mapped into
the PRBs having different PRB numbers at the first slot and the
second slot. Two PRBs, which are respectively located at two slots
of the subframe and have the same VRB number, will be referred to
as a pair of VRBs.
[0051] FIG. 3 illustrates a downlink (DL) subframe structure used
in 3GPP LTE/LTE-A.
[0052] Referring to FIG. 3, a DL subframe is divided into a control
region and a data region. A maximum of three (four) OFDM symbols
located in a front portion of a first slot within a subframe
correspond to the control region to which a control channel is
allocated. A resource region available for PDCCH transmission in
the DL subframe is referred to as a PDCCH region hereinafter. The
remaining OFDM symbols correspond to the data region to which a
physical downlink shared chancel (PDSCH) is allocated. A resource
region available for PDSCH transmission in the DL subframe is
referred to as a PDSCH region hereinafter. Examples of downlink
control channels used in 3GPP LTE include a physical control format
indicator channel (PCFICH), a physical downlink control channel
(PDCCH), a physical hybrid ARQ indicator channel (PHICH), etc. The
PCFICH is transmitted at a first OFDM symbol of a subframe and
carries information regarding the number of OFDM symbols used for
transmission of control channels within the subframe. The PHICH is
a response of uplink transmission and carries an HARQ
acknowledgment (ACK)/negative acknowledgment (NACK) signal.
[0053] Control information carried on the PDCCH is called downlink
control information (DCI). The DCI contains resource allocation
information and control information for a UE or a UE group. For
example, the DCI includes a transport format and resource
allocation information of a downlink shared channel (DL-SCH), a
transport format and resource allocation information of an uplink
shared channel (UL-SCH), paging information of a paging channel
(PCH), system information on the DL-SCH, information about resource
allocation of an upper layer control message such as a random
access response transmitted on the PDSCH, a transmit control
command set with respect to individual UEs in a UE group, a
transmit power control command, information on activation of a
voice over IP (VoIP), downlink assignment index (DAI), etc. The
transport format and resource allocation information of the DL-SCH
are also called DL scheduling information or a DL grant and the
transport format and resource allocation information of the UL-SCH
are also called UL scheduling information or a UL grant. The size
and purpose of DCI carried on a PDCCH depend on DCI format and the
size thereof may be varied according to coding rate. Various
formats, for example, formats 0 and 4 for uplink and formats 1, 1A,
1B, 1C, 1D, 2, 2A, 2B, 2C, 3 and 3A for downlink, have been defined
in 3GPP LTE. Control information such as a hopping flag,
information on RB allocation, modulation coding scheme (MCS),
redundancy version (RV), new data indicator (NDI), information on
transmit power control (TPC), cyclic shift demodulation reference
signal (DMRS), UL index, channel quality information (CQI) request,
DL assignment index, HARQ process number, transmitted precoding
matrix indicator (TPMI), precoding matrix indicator (PMI), etc. is
selected and combined based on DCI format and transmitted to a UE
as DCI.
[0054] In general, a DCI format for a UE depends on transmission
mode (TM) set for the UE. In other words, only a DCI format
corresponding to a specific TM can be used for a UE configured in
the specific TM.
[0055] A PDCCH is transmitted on an aggregation of one or several
consecutive control channel elements (CCEs). The CCE is a logical
allocation unit used to provide the PDCCH with a coding rate based
on a state of a radio channel. The CCE corresponds to a plurality
of resource element groups (REGs). For example, a CCE corresponds
to 9 REGs and an REG corresponds to 4 REs. 3GPP LTE defines a CCE
set in which a PDCCH can be located for each UE. A CCE set from
which a UE can detect a PDCCH thereof is called a PDCCH search
space, simply, search space. An individual resource through which
the PDCCH can be transmitted within the search space is called a
PDCCH candidate. A set of PDCCH candidates to be monitored by the
UE is defined as the search space. In 3GPP LTE/LTE-A, search spaces
for DCI formats may have different sizes and include a dedicated
search space and a common search space. The dedicated search space
is a UE-specific search space and is configured for each UE. The
common search space is configured for a plurality of UEs.
Aggregation levels defining the search space is as follows.
TABLE-US-00003 TABLE 3 Search Space Number of Aggregation Level
PDCCH candidates Type L Size [in CCEs] M.sup.(L) UE- 1 6 6 specific
2 12 6 4 8 2 8 16 2 Common 4 16 4 8 16 2
[0056] A PDCCH candidate corresponds to 1, 2, 4 or 8 CCEs according
to CCE aggregation level. An eNB transmits a PDCCH (DCI) on an
arbitrary PDCCH candidate with in a search space and a UE monitors
the search space to detect the PDCCH (DCI). Here, monitoring refers
to attempting to decode each PDCCH in the corresponding search
space according to all monitored DCI formats. The UE can detect the
PDCCH thereof by monitoring plural PDCCHs. Since the UE does not
know the position in which the PDCCH thereof is transmitted, the UE
attempts to decode all PDCCHs of the corresponding DCI format for
each subframe until a PDCCH having the ID thereof is detected. This
process is called blind detection (or blind decoding (BD)).
[0057] The eNB can transmit data for a UE or a UE group through the
data region. Data transmitted through the data region may be called
user data. For transmission of the user data, a physical downlink
shared channel (PDSCH) may be allocated to the data region. A
paging channel (PCH) and downlink-shared channel (DL-SCH) are
transmitted through the PDSCH. The UE can read data transmitted
through the PDSCH by decoding control information transmitted
through a PDCCH. Information representing a UE or a UE group to
which data on the PDSCH is transmitted, how the UE or UE group
receives and decodes the PDSCH data, etc. is included in the PDCCH
and transmitted. For example, if a specific PDCCH is CRC (cyclic
redundancy check)-masked having radio network temporary identify
(RNTI) of "A" and information about data transmitted using a radio
resource (e.g., frequency position) of "B" and transmission format
information (e.g., transport block size, modulation scheme, coding
information, etc.) of "C" is transmitted through a specific DL
subframe, the UE monitors PDCCHs using RNTI information and a UE
having the RNTI of "A" detects a PDCCH and receives a PDSCH
indicated by "B" and "C" using information about the PDCCH.
[0058] A reference signal (RS) to be compared with a data signal is
necessary for the UE to demodulate a signal received from the eNB.
A reference signal refers to a predetermined signal having a
specific waveform, which is transmitted from the eNB to the UE or
from the UE to the eNB and known to both the eNB and UE. The
reference signal is also called a pilot. Reference signals are
categorized into a cell-specific RS shared by all UEs in a cell and
a modulation RS (DM RS) dedicated for a specific UE. A DM RS
transmitted by the eNB for demodulation of downlink data for a
specific UE is called a UE-specific RS. Both or one of DM RS and
CRS may be transmitted on downlink. When only the DM RS is
transmitted without CRS, an RS for channel measurement needs to be
additionally provided because the DM RS transmitted using the same
precoder as used for data can be used for demodulation only. For
example, in 3GPP LTE(-A), CSI-RS corresponding to an additional RS
for measurement is transmitted to the UE such that the UE can
measure channel state information. CSI-RS is transmitted in each
transmission period corresponding to a plurality of subframes based
on the fact that channel state variation with time is not large,
unlike CRS transmitted per subframe.
[0059] FIG. 4 illustrates an exemplary uplink subframe structure
used in 3GPP LTE/LTE-A.
[0060] Referring to FIG. 4, a UL subframe can be divided into a
control region and a data region in the frequency domain. One or
more PUCCHs (physical uplink control channels) can be allocated to
the control region to carry uplink control information (UCI). One
or more PUSCHs (Physical uplink shared channels) may be allocated
to the data region of the UL subframe to carry user data.
[0061] In the UL subframe, subcarriers spaced apart from a DC
subcarrier are used as the control region. In other words,
subcarriers corresponding to both ends of a UL transmission
bandwidth are assigned to UCI transmission. The DC subcarrier is a
component remaining unused for signal transmission and is mapped to
the carrier frequency f0 during frequency up-conversion. A PUCCH
for a UE is allocated to an RB pair belonging to resources
operating at a carrier frequency and RBs belonging to the RB pair
occupy different subcarriers in two slots. Assignment of the PUCCH
in this manner is represented as frequency hopping of an RB pair
allocated to the PUCCH at a slot boundary. When frequency hopping
is not applied, the RB pair occupies the same subcarrier.
[0062] The PUCCH can be used to transmit the following control
information. [0063] Scheduling Request (SR): This is information
used to request a UL-SCH resource and is transmitted using On-Off
Keying (OOK) scheme. [0064] HARQ ACK/NACK: This is a response
signal to a downlink data packet on a PDSCH and indicates whether
the downlink data packet has been successfully received. A 1-bit
ACK/NACK signal is transmitted as a response to a single downlink
codeword and a 2-bit ACK/NACK signal is transmitted as a response
to two downlink codewords. HARQ-ACK responses include positive ACK
(ACK), negative ACK (NACK), discontinuous transmission (DTX) and
NACK/DTX. Here, the term HARQ-ACK is used interchangeably with the
term HARQ ACK/NACK and ACK/NACK. [0065] Channel State Indicator
(CSI): This is feedback information about a downlink channel.
Feedback information regarding MIMO includes a rank indicator (RI)
and a precoding matrix indicator (PMI).
[0066] The quantity of control information (UCI) that a UE can
transmit through a subframe depends on the number of SC-FDMA
symbols available for control information transmission. The SC-FDMA
symbols available for control information transmission correspond
to SC-FDMA symbols other than SC-FDMA symbols of the subframe,
which are used for reference signal transmission. In the case of a
subframe in which a sounding reference signal (SRS) is configured,
the last SC-FDMA symbol of the subframe is excluded from the
SC-FDMA symbols available for control information transmission. A
reference signal is used to detect coherence of the PUCCH. The
PUCCH supports various formats according to information transmitted
thereon.
[0067] Table 4 shows the mapping relationship between PUCCH formats
and UCI in LTE/LTE-A.
TABLE-US-00004 TABLE 4 Number of bits per PUCCH Modulation
subframe, format scheme M.sub.bit Usage Etc. 1 N/A N/A SR
(Scheduling Request) 1a BPSK 1 ACK/NACK or One codeword SR +
ACK/NACK 1b QPSK 2 ACK/NACK or Two codeword SR + ACK/NACK 2 QPSK 20
CQI/PMI/RI Joint coding ACK/NACK (extended CP) 2a QPSK + 21
CQI/PMI/RI + Normal CP BPSK ACK/NACK only 2b QPSK + 22 CQI/PMI/RI +
Normal CP QPSK ACK/NACK only 3 QPSK 48 ACK/NACK or SR + ACK/NACK or
CQI/PMI/RI + ACK/NACK
[0068] Referring to Table 4, PUCCH formats 1/1a/1b are used to
transmit ACK/NACK information, PUCCH format 2/2a/2b are used to
carry CSI such as CQI/PMI/RI and PUCCH format 3 is used to transmit
ACK/NACK information.
[0069] Reference Signal (RS)
[0070] When a packet is transmitted in a wireless communication
system, signal distortion may occur during transmission since the
packet is transmitted through a radio channel. To correctly receive
a distorted signal at a receiver, the distorted signal needs to be
corrected using channel information. To detect channel information,
a signal known to both a transmitter and the receiver is
transmitted and channel information is detected with a degree of
distortion of the signal when the signal is received through a
channel. This signal is called a pilot signal or a reference
signal.
[0071] When data is transmitted/received using multiple antennas,
the receiver can receive a correct signal only when the receiver is
aware of a channel state between each transmit antenna and each
receive antenna. Accordingly, a reference signal needs to be
provided per transmit antenna, more specifically, per antenna
port.
[0072] Reference signals can be classified into an uplink reference
signal and a downlink reference signal. In LTE, the uplink
reference signal includes:
[0073] i) a demodulation reference signal (DMRS) for channel
estimation for coherent demodulation of information transmitted
through a PUSCH and a PUCCH; and
[0074] ii) a sounding reference signal (SRS) used for an eNB to
measure uplink channel quality at a frequency of a different
network.
[0075] The downlink reference signal includes:
[0076] i) a cell-specific reference signal (CRS) shared by all UEs
in a cell;
[0077] ii) a UE-specific reference signal for a specific UE
only;
[0078] iii) a DMRS transmitted for coherent demodulation when a
PDSCH is transmitted;
[0079] iv) a channel state information reference signal (CSI-RS)
for delivering channel state information (CSI) when a downlink DMRS
is transmitted;
[0080] v) a multimedia broadcast single frequency network (MBSFN)
reference signal transmitted for coherent demodulation of a signal
transmitted in MB SFN mode; and
[0081] vi) a positioning reference signal used to estimate
geographic position information of a UE.
[0082] Reference signals can be classified into a reference signal
for channel information acquisition and a reference signal for data
demodulation. The former needs to be transmitted in a wide band as
it is used for a UE to acquire channel information on downlink
transmission and received by a UE even if the UE does not receive
downlink data in a specific subframe. This reference signal is used
even in a handover situation. The latter is transmitted along with
a corresponding resource by an eNB when the eNB transmits a
downlink signal and is used for a UE to demodulate data through
channel measurement. This reference signal needs to be transmitted
in a region in which data is transmitted.
[0083] To satisfy the aforementioned reduction in latency, i.e.,
low latency, it may be required to reduce TTI that is a minimum
unit of data transmission to newly design a shortened TTI (sTTI) of
0.5 msec or less. For example, as illustrated in FIG. 5, to shorten
user plane (U-plane) latency to a time point when a UE completely
transmits ACK/NACK (A/N) from a time point when an eNB begins to
transmit data (PDCCH and PDSCH) to 1 msec, a sTTI may be configured
in units of about 3 OFDM symbols.
[0084] In a DL environment, a PDCCH (i.e., sPDCCH) for data
transmission/scheduling in such a sTTI and a PDSCH (i.e., sPDSCH)
for transmission in the sTTI may be transmitted and, for example,
as illustrated in FIG. 6, a plurality of sTTIs may be configured
using different OFDM symbols in one subframe. Particularly, OFDM
symbols included in the sTTI may be configured by excluding OFDM
symbols transmitted by legacy control channels. The sPDCCH and the
sPDSCH may be transmitted in the sTTI in the form of time division
multiplexing (TDM) using different OFDM symbol regions and may be
transmitted in the form of frequency division multiplexing (FDM)
using different PRB domain/frequency resources.
[0085] In a UL environment as similar with the DL environment, data
transmission/scheduling in a sTTI is allowed, channels
corresponding to a legacy TTI based PUCCH and PUSCH are referred to
as sPUCCH and sPUSCH, respectively.
[0086] In the specification, the present invention is described
below in terms of an LTE/LTE-A system. In an existing LTE/LTE-A,
when having a normal CP, a subframe of 1 ms may include 14 OFDM
symbols and, when a symbol is configured with a TTI in a shorter
unit than 1 ms, a plurality of TTIs may be configured in one
subframe. A method of configuring a plurality of TTIs may configure
two symbols, three symbols, four symbols, and seven symbols as one
TTI, as in an embodiment shown in FIG. 7 below. Although not shown,
the case in which one symbol is configured as a TTI may also be
configured. When one symbol is one TTI unit, 12 TTIs may be
generated on the assumption that a legacy PDCCH is transmitted in
two OFDM symbols. Similarly, as shown in FIG. 7A, when two symbols
correspond to one TTI unit, 6 TTIs may be generated, as shown in
FIG. 7B, when three symbols correspond to one TTI unit, 4 TTIs may
be generated and, as shown in FIG. 7C, when four symbols correspond
to one TTI unit, 3 TTIs may be generated. Needless to say, in this
case, first two OFDM symbols may be assumed to transmit a legacy
PDCCH.
[0087] As shown in FIG. 7D, when seven symbols are configured with
one TTI, one TTI of seven symbol units including a legacy PDCCH and
seven subsequent symbols may be configured as one TTI. In this
case, in the case of a UE that supports a sTTI, when one TTI
includes seven symbols, it may be assumed that puncture or
rate-matching is performed on two OFDM symbols positioned at a fore
end for transmitting a legacy PDCCH with respect to a TTI (first
symbol) positioned at a fore end of one subframe and it may be
assumed that corresponding data and/or control information are
transmitted in five symbols. On the other hand, it may be assumed
that a UE is capable of transmitting data and/or control
information all seven symbols without a punctured or rate-matched
resource region with respect to a TTI (second slot) positioned at a
rear end of one subframe.
[0088] According to the present invention, a sTTI including two
OFDM symbols (hereinafter, "OS") and a sTTI including three OSs may
be considered to include sTTI structures that are combined and
present in one subframe, as shown in FIG. 8. The sTTI including
2-OS or 3-OS sTTIs may be simply defined as 2-symbol sTTI (i.e.,
2-OS sTTI). Also, 2-symbol sTTI or 3-symbol sTTI may be simply
referred to as 2-symbol TTI or 3-symbol TTI, respectively, and it
is clear that these are TTIs shorter than the 1 ms TTI, which is
the legacy TTI, which is the premise of the present invention. That
is, in the specification, the term "TTI" is referred to instead of
sTTI, the term TTI means the sTTI, and regardless of its name, what
the present invention proposes is a communication scheme in a
system composed of TTIs shorter than a legacy TTI.
[0089] Also, in this specification, numerology refers to defining a
length of a TTI to be applied to the wireless communication system,
a subcarrier interval and the like, or a parameter or a
communication structure or system based on the parameter such as
the defined length of the TTI or sub-carrier spacing.
[0090] As shown in FIG. 8A, a sPDCCH may also be transmitted
depending on the number of symbols of a PDCCH in a
<3,2,2,2,2,3> sTTI pattern. In a <2,3,2,2,2,3> sTTI
pattern of FIG. 8B, it may be difficult to transmit an sPDCCH due
to a legacy PDCCH region.
[0091] Collision Handling for UL Channels
[0092] Assume that transmission timings of a plurality of UL
channels with different numerologies (e.g., a TTI length, a
subcarrier spacing, etc.) overlap with each other on time, for
example, the case in which transmission timings of UL channels with
a longer TTI and a shorter TTI overlap with each other. A
transmission timing of each channel may be is determined based on a
DL/UL subcarrier spacing and a TTI and, thus, a time taken to
assign power to each channel (to transmit PUCCH or PUSCH) may be
changed and transmission of the shorter TTI may be started during
transmission of the longer TTI. In this case, it may be difficult
to consider power of the shorter TTI when power of the longer TTI
is determined and, thus, (1) transmission of the longer TTI may be
stopped or (2) symbols that overlap with the shorter TTI may be
punctured/power-reduced and may be transmitted. However, in the
former case, the longer TTI UL channel needs to be always dropped
and, thus, UL latency for the longer TTI may be degraded and, on
the other hand, in the latter case, as the number of symbols that
overlap with the shorter TTI is increased, the reliability of the
punctured/power-reduced longer TTI UL channel may be degraded.
[0093] A rule may be defined to assign higher priority to shorter
transmission or higher QoS requirement channel when different
numerologies are supported and two UL transmissions overlap with
each other on time/frequency resources and, thus, one UL
transmission needs to be selected in terms of one UE. As a method
of determining priority between channels that collide with each
other, the priority may be configured via high layer signaling or
may be transmitted via dynamic scheduling information. In this
case, a rule may be defined to transmit information related to a
processing method of a channel with lower priority in DCI for
scheduling a higher priority channel or to transmit the information
in scheduling grant that is received later among UL grants for two
channels. As another method, a rule may be defined to
semi-statically configure information related to a processing
method of a channel with lower priority to a UE and to process a
channel with lower priority according to the configuration by the
UE. Particularly, the processing method of the channel with lower
priority may include dropping, puncturing, and/or suspending &
resuming, etc. and, here, suspending & resuming may be
different from puncturing in that transmission of the channel with
lower priority is stopped and delayed.
[0094] More particularly, even if a specific behavior is
indicated/configured via the dynamic indication and/or semi-static
configuration, the processing method of the channel with lower
priority may be differently determined depending on a
time/frequency resource occupied region of a higher priority
channel and/or stolen time/frequency resource region of a lower
priority channel. For example, even if the channel with lower
priority is indicated/configured to be punctured via the dynamic
indication and/or semi-static configuration, when DMRSs of the
higher priority channel and the lower priority channel overlap with
each other, a rule may be defined to drop the lower priority
channel.
[0095] More generally, operations of all channels may be
differently applied depending on a time point of collision between
corresponding channels rather than being determined depending on
priority between the channels. That is, a specific period in a
resource period of the lower priority channel may not have high
priority or may not be preempted compared with the higher priority
channel and, in this case, on-going transmission may be
preferentially handled irrespective of priority. For example, when
a UE is capable of skipping specific UL grant, upon receiving UL
grant for the higher priority channel, the UE may piggyback and
transmit data, to be transmitted to the lower priority channel, to
the higher priority channel together or may transmit a
corresponding payload through the higher priority channel.
[0096] When a channel transmitted without UL grant has higher
priority in consideration of collision between the channel
transmitted without UL grant and a channel transmitted based on UL
grant, the lower priority channel may be transmitted based on UL
grant for scheduling the lower priority channel as a processing
method of the corresponding lower priority channel. In the
corresponding case, an operation corresponding to the lower
priority may be determined but priority of the corresponding UL
grant may also be determined. The UE may determine priority with
respect to transmission of a UL grant-free resource, to be
transmitted by the UE, depending on corresponding priority
information.
[0097] An example of the priority may be information on a bearer to
which UL grant is mapped or Quality of Service (QoS) information.
Alternatively, an example of the priority may be indication about
whether preemption is possible or not.
[0098] When preemption is possible, an operation of the case in
which preemption is performed may be indicated together. In this
case, the higher priority channel or UL transmission without grant
may be present or may not be present and, thus, the corresponding
method may be assumed to be activated only the higher priority
channel or UL transmission without grant is present. More
particularly, when a UL resource is indicated via UL transmission
without grant and UL grant, a rule may be defined to transmit data
using a resource for UL transmission without grant and to skip the
UL grant. Accordingly, dropping of an operation on the lower
priority channel when UL transmission without grant and UL
grant-based transmission collide with each other and dropping of
collision between UL grant-based channels may be different. In the
former case, dropping may include skipping in which UL transmission
with respect to UL grant-based transmission is not started or may
refer to skip (according to user selection). Alternatively, these
operations may be related to configuration of priority between UL
grant-based scheduling and a UL grant-free resource or scheduling
grant received at two different transmission and reception points
(TRPs).
[0099] In the corresponding case, a timing alignment (TA) value of
the higher priority channel transmission and a TA value of the
lower priority channel transmission may be different. Accordingly,
when an operation such as puncturing, suspending & resuming, or
the like is indicated, a gap for adjusting a TA value except for
the higher priority channel transmission period may be assumed to
be generated back or front (depending on a TA value, for example,
when a TA of the higher priority channel is high, the gap is
required front and, in an opposite case, the gap is required back).
The corresponding gap may be formed by the UE by a TA difference or
may be formed by emptying a gap configured by a network.
Alternatively, the UE may notify the network about the TA
difference and the network may configure an appropriate gap. The
corresponding method may also be applied to collision between UL
transmission without grant and UL grant-based transmission and the
network needs to know the corresponding gap and, thus, when a TA
value is changed, it may be considered that the UE reports the
change in TA value to the network. According to a UL grant-free TA
configuration, when a UE is capable of assuming an effective timing
window of a TA value applied via UL grant-based transmission or the
like from a corresponding TRP and the TA is not updated even when a
corresponding timing elapses, a TA value may be configured to be
unknown. When the TA value is unknown, the UE may perform
transmission assuming a maximum TA value in the case of UL
transmission without grant (the maximum TA value is assumed to be
preset), may assume a CP to be increased by the maximum TA, or may
transmit a preamble. In addition, a UL grant-free resource for this
case may be separately set.
[0100] When transmission timings of a plurality of UL channels
having different QoSs and/or requirements overlap with each other
on time, a different method from existing handling may also be
applied. For example, the case of channel transmission for traffic
in which higher reliability and/or lower latency are required may
be assigned with as high priority as possible to be prevented from
collision with other channels.
[0101] In more detail, when PUCCH with respect to traffic in which
a specific channel requires higher reliability and/or lower latency
and a channel related to traffic in which relatively lower
reliability and/or higher latency are required overlap with each
other on time, a rule may be defined to transmit PUCCH by a UE, to
assign lower priority to PUSCH, and to drop/suspend the PUSCH, or
to perform puncturing, power reduction, or the like on the PUSCH,
despite collision between PUCCH and PUSCH. This operation may also
be applied to a situation in which, particularly, simultaneous
transmission of PUCCH/PUSCH is not configured or UE capability is
not satisfied. Even if simultaneous transmission of PUCCH/PUSCH is
configured or possible (or irrespective simultaneous transmission
configuration/capability), the operation may also be applied only
to a power-limited situation. The operation may be applied only to
a specific PUCCH format and, for example, may be applied to a PUCCH
format of a large coverage group (and/or a small maximum payload
size group).
[0102] When PUCCH is repeated/segmented and is transmitted over a
plurality of TTIs in a time domain based on the operation, a rule
may be defined to assign as high priority as possible during a
first TTI or a plurality of TTIs including the first TTI among the
plurality of TTIs and to assign as low priority as possible to
PUCCH corresponding to a subsequent TTI. That is, when PUCCH is
repeated/segmented and is transmitted over a plurality of TTIs in a
time domain, priority may be differently configured according to a
TTI for transmitting the PUCCH.
[0103] More generally, when transmission timings of a plurality of
UL channels that have different TTI lengths, numerologies, QoSs,
service types, and/or requirements overlap with each other on time,
a rule may be defined to assign as high priority as possible to a
channel that performs a repetition/segmentation operation and to
drop/suspend the other (or some) channels or perform puncturing,
power reduction, or the like on the other (or some) channels by a
UE. Alternatively, in the case of a channel that performs a
repetition/segmentation operation, high priority may not be always
assigned, but a rule may be defined to assign high priority to some
of channels/transmissions via a repetition/segmentation operation
to ensure transmission and to assign low priority to the other some
of the channels/transmissions.
[0104] When transmission timings of a plurality of UL channels with
different TTI lengths, numerologies, QoSs, service types, and/or
requirements overlap with each other on time, a rule may be defined
to ensure the minimum number of times of repetition/segmentation of
a channel that performs the repetition/segmentation operation. In
more detail, even if the channel that performs the
repetition/segmentation operation is pushed back on the priority is
dropped/suspended or punctured, a UE may determine whether the
channel is dropped/suspended or punctured in such a way that
transmission with the smaller number of times than the number of
times, which is predefined or set/indicated via set/indicated via
high/physical layer signal is not performed. In this case, The UE
may determine whether the channel is dropped/suspended or punctured
in consideration of the number of transmission times of the channel
during the repetition/segmentation operation up to now and/or the
number of transmission times of the channel that performs the
repetition/segmentation operation in the future.
[0105] For example, when the number of repetition times is 10 TTIs
(all transmissions include once+repeated transmissions ten
times=all transmissions eleven times) and a minimum repetition
number of times to be ensured to be minimum is 5 TTI, if TTI #n and
TTI #n+1 are transmitted and TTI #n+2 to TTI #n+6 are dropped in
the case of transmission to TTI #n+10 from TTI #n, a rule may be
defined not to drop a channel in which collision occurs in TTI #n+7
and the repetition operation is performed and which needs to be
dropped and to drop/suspend the other channels.
[0106] As another method, a rule may be defined not to drop/suspend
or puncture a corresponding channel by another channel up to a
minimum number of repetition/segmentation times of a channel that
performs the repetition/segmentation operation. With regard to a
channel corresponding to a repetition/segmentation operation after
the minimum number of repetition/segmentation times, a
drop/suspension or puncturing operation may be determined according
to a generally defined rule.
[0107] According to the current LTE standard, in a situation in
which 1 ms PUSCH to be transmitted in subframe n+k via UL grant DCI
in subframe n is scheduled, when SPUSCH is scheduled at a time
point between subframe (n+1) and subframe (n+W_UL) (here,
W_UL<=k), a rule may be defined in such a way that a UE does not
expect transmission of 1 ms PUSCH. Related standard is stated in
Reference below.
[0108] [Reference]
[0109] For a serving cell, and a UE configured with higher layer
parameter ul-TTI-Length, the UE is not expected to transmit
subframe-based PUSCH in a given subframe corresponding to
PDCCH/EPDCCH with uplink DCI format other than 7-0A/7-0B received
in subframe n if the UE detects PDCCH/SPDCCH with uplink DCI format
7-0A/7-0B in any subframe from subframe n+1 to subframe n+WUL
corresponding to a PUSCH transmission, and WUL is indicated by skip
SubframeProcessing capability.
[0110] In this case, when UCI such as HARQ-ACK is expected to be
transmitted in 1 ms PUSCH, the corresponding UCI transmitting
method is proposed as follows. [0111] Option 1: A rule may be
defined to transmit UCI that is expected to be transmitted in 1 ms
PUSCH, in 1 ms PUCCH in a subframe in which PUSCH is expected to be
transmitted. [0112] Option 2: A rule may be defined to transmit UCI
that is expected to be transmitted in 1 ms PUSCH, in SPUCCH in sTTI
(e.g., first sTTI in a subframe in which PUSCH is expected to be
expected) predefined in a subframe in which PUSCH is expected to be
transmitted or sTTI configured via a high layer signal. Here, a
rule may be defined in such a way that a TTI length of SPUCCH
complies with a UL TTI length configured in a PUCCH group/cell
group including a corresponding serving cell or the corresponding
serving cell. When sTTI PUSCH (i.e., SPUSCH) is scheduled at a
corresponding SPUCCH transmitting time point, a rule may be defined
to piggyback the UCI to SPUSCH and, particularly, the piggyback may
be applied to the case in which simultaneous transmission of PUSCH
and PUCCH is not configured. [0113] Option 3: A rule may be defined
to transmit UCI that is expected to be transmitted in 1 ms PUSCH,
in 1 ms PUSCH in a subframe that is expected to be transmitted in
PUSCH. However, the corresponding PUSCH may be channel transmission
that does not include data (UL-SCH) and includes only UCI. In a
situation without UL-SCH in existing LTE, the number of coded
symbols to which HARQ-ACK of PUSCH is to be mapped may be
determined according to Equation 1 below.
[0113] Q ' = min ( O M sc PUSCH N symb PUSCH .beta. offset PUSCH O
CQI - MIN , N symb UCI M offset PUSCH ) [ Equation 1 ]
##EQU00001##
[0114] Here, O.sub.CQI-MIN is a value obtained by summing a CQI bit
number and a CRC bit number of all CSIs (processes) for receiving
CSI trigger. When the present option is applied, the CSI trigger is
not ensured to be received in the corresponding subframe and, thus,
O.sub.CQI-MIN may be 0 and it may not be possible to acquire the
above Q' value. Accordingly, when the present option is applied,
O.sub.CQI-MIN may be replaced with a total sum of data bit number
corresponding to each code block. This means that the data bit
number is the same as an equation in which actual transmission is
assumed and, in this regard, a data bit is not actually transmitted
in the present option and, thus, a rule may also be defined to
deliver HARQ-ACK in all PUSCH REs (e.g.,
Q'=N.sub.symb.sup.UCIM.sub.sc.sup.PUSCH) or to more deliver
HARQ-ACK bits in many REs (e.g., a method such as "total number of
REs to which PUSCH needs to be mapped*offset" and, in this case,
the offset is a value that is equal to or smaller than 1 and may be
a value that is configured via a high layer signal or a
predetermined value). [0115] Option 3-1: A rule may be defined to
transmit UCI that is included in 1 ms PUSCH and is expected to be
transmitted, in 1 ms PUSCH in a subframe to be expected to be
transmitted in PUSCH and, in this case, the corresponding PUSCH may
be channel transmission that does not include data (UL-SCH) and
includes only UCI. In particular, HARQ-ACK may be mapped only to
four SC-FDMA symbols of an actual PUSCH and, thus, it may not be
desired to perform transmission in all subframes to reduce power
consumption of a UE and/or to reduce interference with respect to a
UL channel from another UE.
[0116] Accordingly, in this case, a rule may be defined in such a
way that a UE delivers power only in a symbol to which HARQ-ACK and
DMRS are mapped and to reduce power in the other symbols (or to
reduce to zero). As another method, a rule may be defined to
partially transmit PUSCH to prevent power transient and, as a
detailed example, a rule may be defined in such a way that a UE
delivers and transmits power only in a time period from a first
symbol (e.g., a third symbol in 1 ms PUSCH or a third symbol of a
first slot in 1 ms PUSCH), to which HARQ-ACK in a subframe is
mapped, to a last symbol (e.g., a twelfth symbol in 1 ms PUSCH or a
fifth symbol of a second slot in 1 ms PUSCH) and reduces power in
the other symbols (or to reduce to zero) [0117] Option 3-2: A rule
may be defined to transmit UCI expected to be transmitted in 1 ms
PUSCH in the above situation, in 1 ms PUSCH in a subframe expected
to transmit PUSCH and, in this case, the corresponding PUSCH may be
channel transmission that does not include data (UL-SCH) and
includes only UCI. In this case, a rule may be defined in such a
way that a UE transmits PUSCH only in a RB including a RE to which
UCI is mapped among RBs indicated via PUSCH resource assignment.
This is for reducing power consumption of a UE and/or reducing
interference with respect to a UL channel from other UEs. [0118]
Option 4: It may not be desired to drop HARQ-ACK of UCI included in
1 ms PUSCH. For example, when carrier agglomeration is configured,
1 ms PUSCH(s) including HARQ-ACK, to be transmitted in all carriers
or serving cells, may be dropped, thereby rather increasing latency
of a system. Accordingly, in a situation in which 1 ms PUSCH to be
transmitted in subframe n+k through UL grant DCI in subframe n,
when SPUSCH is scheduled in a time period between subframe n to
subframe n+W_UL or subframe n+1 or subframe n+W_UL (here,
W_UL<=k), a rule may be defined not to drop 1 ms PUSCH(s)
including HARQ-ACK and to drop only 1 ms PUSCH to be transmitted in
the other carriers or cells in which 1 ms PUSCH(s) including the
HARQ-ACK is not transmitted, that is, 1 ms PUSCH that does not
include HARQ-ACK (that is, to drop or not according to an
embodiment of a UE). [0119] Option 4-1: Alternatively, a rule may
be defined to finally drop 1 ms PUSCH including HARQ-ACK among
PUSCHs to be dropped. In other words, a rule may be defined to
preferentially drop PUSCH that does not include HARQ-ACK among 1 ms
PUSCHs scheduled in a plurality of carriers or cells. In addition,
a rule may be defined to transmit corresponding HARQ-ACK (and/or
other UCI including RI/CQI/PMI) in 1 ms PUCCH when PUSCH is dropped
in the corresponding subframe in all carriers or cells up to 1 ms
PUSCH including HARQ-ACK. [0120] Option 5: In a situation in which
1 ms PUSCH transmitted in subframe n+k is scheduled via UL grant
DCI in subframe n, a rule may be defined to transmit information on
partial or entire CSI in 1 ms PUSCH without UL-SCH when SPUSCH is
scheduled at a time point between subframe n to subframe n+W_UL or
subframe n+1 to subframe n+W_UL (here, W_UL<=k) and CSI is
expected to be transmitted in 1 ms PUSCH. In detail, at least RI
may be transmitted in 1 ms PUSCH without UL-SCH or RI and CQI/PMI
may be transmitted in 1 ms PUSCH without UL-SCH. This operation may
be applied when only the above conditions are satisfied
irrespective a condition such as the RB number and/or MCS index,
etc. that are required to transmit "CSI on PUSCH without
UL-SCH".
[0121] Collision Handling Between Transmissions with Grant and
without Grant
[0122] A next-generation system has introduced a method of largely
reducing transmission latency depending on an application field. In
particular, introduction of grant-free UL transmission in which UL
transmission according to determination of a UE instead of
scheduling based on existing UL grant with respect to UL
transmission has been considered. In more detail, an eNB may
configure a resource set for UL transmission without grant and may
notify a UE about the configuration and the UE may start UL
transmission without UL grant. For convenience of description, this
transmission method is referred to as "UL transmission without
grant". The "UL transmission without grant" may include a
semi-persistent transmission or SPS-like transmission method of
existing LTE. On the other hand, for convenience of description, a
UL (data) transmitting method via UL grant DCI including scheduling
information of an eNB is referred to as "UL transmission with
grant. When UL transmission without grant and UL transmission with
grant with different TTI lengths and/or numerologies overlap with
each other on time, a behavior of a UE is proposed as follows.
[0123] Option 1: As high priority as possible may be always
assigned to "UL transmission without grant" irrespective of a TTI
length and/or numerology. When simultaneous transmission is not
possible, the UE may drop or suspend a channel corresponding to UL
transmission with grant. This is because the UE is exposed to
transmit a channel using a "UL transmission without grant" method
with respect to traffic with relatively high latency requirement.
[0124] Option 2: When a channel using a "UL transmission without
grant" method has a shorter TTI length and/or higher subcarrier
spacing than a channel using a "UL transmission with grant" method,
as high priority as possible may be assigned to the channel using
the "UL transmission without grant" method. On the other hand, in
an opposite case, that is, when the channel using the "UL
transmission without grant" method has a longer TTI length and/or
shorter subcarrier spacing than the channel using the "UL
transmission with grant", as high priority as possible may be
assigned to the channel using the "UL transmission with grant"
method.
[0125] The aforementioned proposed methods may be included in one
of embodiments of the present invention and, thus, may be
considered as a type of proposed methods. The aforementioned
proposed methods may be independently embodied but may be embodied
in a combination (or union) of some of the proposed methods. A rule
may be defined to indicate information on whether the proposed
methods are applied (or information on the rule of the proposed
methods) to a UE through a predefined signal (e.g., a physical
layer signal or a high layer signal).
[0126] FIG. 9 is a block diagram illustrating a transmitting device
10 and a receiving device configured to implement embodiments of
the present invention. Each of the transmitting device 10 and
receiving device 20 includes a transmitter/receiver 13, 23 capable
of transmitting or receiving a radio signal that carries
information and/or data, a signal, a message, etc., a memory 12, 22
configured to store various kinds of information related to
communication with a wireless communication system, and a processor
11, 21 operatively connected to elements such as the
transmitter/receiver 13, 23 and the memory 12, 22 to control the
memory 12, 22 and/or the transmitter/receiver 13, 23 to allow the
device to implement at least one of the embodiments of the present
invention described above.
[0127] The memory 12, 22 may store a program for processing and
controlling the processor 11, 21, and temporarily store
input/output information. The memory 12, 22 may also be utilized as
a buffer. The processor 11, 21 controls overall operations of
various modules in the transmitting device or the receiving device.
Particularly, the processor 11, 21 may perform various control
functions for implementation of the present invention. The
processors 11 and 21 may be referred to as controllers,
microcontrollers, microprocessors, microcomputers, or the like. The
processors 11 and 21 may be achieved by hardware, firmware,
software, or a combination thereof. In a hardware configuration for
an embodiment of the present invention, the processor 11, 21 may be
provided with application specific integrated circuits (ASICs) or
digital signal processors (DSPs), digital signal processing devices
(DSPDs), programmable logic devices (PLDs), and field programmable
gate arrays (FPGAs) that are configured to implement the present
invention. In the case which the present invention is implemented
using firmware or software, the firmware or software may be
provided with a module, a procedure, a function, or the like which
performs the functions or operations of the present invention. The
firmware or software configured to implement the present invention
may be provided in the processor 11, 21 or stored in the memory 12,
22 to be driven by the processor 11, 21.
[0128] The processor 11 of the transmitter 10 performs
predetermined coding and modulation of a signal and/or data
scheduled by the processor 11 or a scheduler connected to the
processor 11, and then transmits a signal and/or data to the
transmitter/receiver 13. For example, the processor 11 converts a
data sequence to be transmitted into K layers through
demultiplexing and channel coding, scrambling, and modulation. The
coded data sequence is referred to as a codeword, and is equivalent
to a transport block which is a data block provided by the MAC
layer. One transport block is coded as one codeword, and each
codeword is transmitted to the receiving device in the form of one
or more layers. To perform frequency-up transformation, the
transmitter/receiver 13 may include an oscillator. The
transmitter/receiver 13 may include Nt transmit antennas (wherein
Nt is a positive integer greater than or equal to 1).
[0129] The signal processing procedure in the receiving device 20
is configured as a reverse procedure of the signal processing
procedure in the transmitting device 10. The transmitter/receiver
23 of the receiving device 20 receives a radio signal transmitted
from the transmitting device 10 under control of the processor 21.
The transmitter/receiver 23 may include Nr receive antennas, and
retrieves baseband signals by frequency down-converting the signals
received through the receive antennas. The transmitter/receiver 23
may include an oscillator to perform frequency down-converting. The
processor 21 may perform decoding and demodulation on the radio
signal received through the receive antennas, thereby retrieving
data that the transmitting device 10 has originally intended to
transmit.
[0130] The transmitter/receiver 13, 23 includes one or more
antennas. According to an embodiment of the present invention, the
antennas function to transmit signals processed by the
transmitter/receiver 13, 23 are to receive radio signals and
deliver the same to the transmitter/receiver 13, 23. The antennas
are also called antenna ports. Each antenna may correspond to one
physical antenna or be configured by a combination of two or more
physical antenna elements. A signal transmitted through each
antenna cannot be decomposed by the receiving device 20 anymore. A
reference signal (RS) transmitted in accordance with a
corresponding antenna defines an antenna from the perspective of
the receiving device 20, enables the receiving device 20 to perform
channel estimation on the antenna irrespective of whether the
channel is a single radio channel from one physical antenna or a
composite channel from a plurality of physical antenna elements
including the antenna. That is, an antenna is defined such that a
channel for delivering a symbol on the antenna is derived from a
channel for delivering another symbol on the same antenna. An
transmitter/receiver supporting the Multiple-Input Multiple-Output
(MIMO) for transmitting and receiving data using a plurality of
antennas may be connected to two or more antennas.
[0131] In embodiments of the present invention, the UE or the
terminal operates as the transmitting device 10 on uplink, and
operates as the receiving device 20 on downlink. In embodiments of
the present invention, the eNB or the base station operates as the
receiving device 20 on uplink, and operates as the transmitting
device 10 on downlink.
[0132] The transmitting device and/or receiving device may be
implemented by one or more embodiments of the present invention
among the embodiments described above.
[0133] According to one of these embodiments, a terminal for
transmitting a UL signal with a short transmission time interval
(TTI) length in a wireless communication system includes a receiver
and a transmitter, and a processor that controls the receiver and
the transmitter and, in this case, the processor receives DL
control information including UL grant and, when transmission
timing of a UL signal corresponding to the UL grant and
transmission timing of a semi-persistent (SPS) UL signal overlap
with each other, and when a TTI length of the first channel on
which a UL signal corresponding to the UL grant is longer than a
TTI length of a second channel in which the SPS UL signal, to
perform UL signal transmission only on the second channel from the
first channel and the second channel at the transmission
timing.
[0134] Upon receiving second DL control information including
second UL grant for scheduling transmission of physical uplink
shared channel (PUSCH) with a shorter length than a TTI length of
the first channel during a time period from a next subframe
("subframe #n+1") of a subframe in which the DL control information
is received to a subframe ("subframe #n+k") in which a UL signal
corresponding to the UL grant is to be transmitted, the processor
may transmit the UL signal corresponding to the UL grant on a
physical uplink control channel (PUCCH) in subframe #n+k.
[0135] Upon receiving second DL control information including
second UL grant for scheduling transmission of physical uplink
shared channel (PUSCH) with a shorter length than a TTI length of
the first channel during a time period from a next subframe
("subframe #n+1") of a subframe in which the DL control information
is received to a subframe ("subframe #n+k") in which a UL signal
corresponding to the UL grant is to be transmitted, the processor
may transmit a UL signal corresponding to the UL grant on a
shortened PUCCH (SPUCCH) in an n.sup.th TTI with a shorter length
than the TTI length of the first channel in subframe #n+k and, in
this case, n may be preconfigured.
[0136] Upon receiving second DL control information including
second UL grant for scheduling transmission of physical uplink
shared channel (PUSCH) with a shorter length than a TTI length of
the first channel during a time period from a next subframe
("subframe #n+1") of a subframe in which the DL control information
is received to a subframe ("subframe #n+k") in which a UL signal
corresponding to the UL grant is to be transmitted, the processor
may transmit a UL signal corresponding to the UL grant on a first
channel that does not include data in subframe #n+k.
[0137] Transmission power may be used only in a symbol to which the
UL signal is mapped in subframe #n+k.
[0138] In addition, power may be used only in a resource block to
which the UL signal is mapped among resource blocks indicated by
the downlink control information in subframe #n+k.
[0139] Detailed descriptions of preferred embodiments of the
present invention have been given to allow those skilled in the art
to implement and practice the present invention. Although
descriptions have been given of the preferred embodiments of the
present invention, it will be apparent to those skilled in the art
that various modifications and variations can be made in the
present invention defined in the appended claims. Thus, the present
invention is not intended to be limited to the embodiments
described herein, but is intended to have the widest scope
consistent with the principles and novel features disclosed
herein.
INDUSTRIAL APPLICABILITY
[0140] The present invention can be used for such a wireless
communication device as a terminal, a relay, a base station, and
the like.
* * * * *