U.S. patent application number 16/917237 was filed with the patent office on 2020-10-22 for data transmission method and user equipment.
The applicant listed for this patent is HUAWEI TECHNOLOGIES CO., LTD.. Invention is credited to Xiaolei TIE, Gengshi WU, Yiling WU, Yubo YANG.
Application Number | 20200336350 16/917237 |
Document ID | / |
Family ID | 1000004929403 |
Filed Date | 2020-10-22 |
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United States Patent
Application |
20200336350 |
Kind Code |
A1 |
TIE; Xiaolei ; et
al. |
October 22, 2020 |
DATA TRANSMISSION METHOD AND USER EQUIPMENT
Abstract
A data transmission method in the present application includes:
determining, by first UE, a frame structure in a time unit, where
the frame structure indicates that N type-1 OFDM symbols and a GP
are included in the time unit, and a subcarrier spacing of each
type-1 OFDM symbol is .DELTA.f.sub.1. Therefore, according to the
data transmission method and the user equipment in embodiments of
the present application, a frame structure in a time unit is
determined. The frame structure indicates that N type-1 OFDM
symbols and a GP are included in the time unit, and a subcarrier
spacing of each type-1 OFDM symbol is .DELTA.f.sub.1. Therefore,
when an NB-IOT system is deployed in an LTE system in an embedded
manner, and when NB-IOT UE is sending data, a channel resource of
the legacy LTE system can be adequately utilized, and a conflict
with a legacy LTE SRS can be avoided.
Inventors: |
TIE; Xiaolei; (Shanghai,
CN) ; YANG; Yubo; (Shanghai, CN) ; WU;
Gengshi; (Shanghai, CN) ; WU; Yiling;
(Beijing, CN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
HUAWEI TECHNOLOGIES CO., LTD. |
Shenzhen |
|
CN |
|
|
Family ID: |
1000004929403 |
Appl. No.: |
16/917237 |
Filed: |
June 30, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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16025697 |
Jul 2, 2018 |
10708098 |
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16917237 |
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PCT/CN2016/076404 |
Mar 15, 2016 |
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16025697 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04L 27/26 20130101;
H04L 27/2605 20130101; H04L 29/06 20130101; H04L 27/2602 20130101;
H04W 72/0453 20130101; H04L 27/2607 20130101 |
International
Class: |
H04L 27/26 20060101
H04L027/26; H04L 29/06 20060101 H04L029/06; H04W 72/04 20060101
H04W072/04 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 31, 2015 |
CN |
PCT/CN2015/100357 |
Claims
1. A data transmission method, wherein the method comprises:
indicating, by a base station, a first subcarrier spacing to a
terminal, wherein the first subcarrier spacing is used by the
terminal to determine a frame structure; and receiving, by the base
station, an N type-1 orthogonal frequency division multiplexing
(OFDM) symbols generated by the terminal based on the frame
structure in a time unit, wherein the frame structure indicates
that the N type-1 OFDM symbols and a guard period (GP) are
comprised in the time unit, wherein the first subcarrier spacing of
each type-1 OFDM symbol is .DELTA.f.sub.1, wherein a first time
length of the GP is greater than a second time length occupied by
one type-2 OFDM symbol, wherein a second subcarrier spacing of the
type-2 OFDM symbol is .DELTA.f.sub.2, and wherein .DELTA.f.sub.1 is
unequal to .DELTA.f.sub.2.
2. The method according to claim 1, wherein N is a positive
integer, and N is a maximum quantity of type-1 OFDM symbols
comprised in the time unit after the second time length occupied by
one type-2 OFDM symbol is subtracted.
3. The method according to claim 1, wherein the GP is used to
prevent the sent type-1 OFDM symbols and a type-2 OFDM symbol sent
by a second terminal from overlapping on a time-frequency
resource.
4. The method according to claim 1, wherein both a third time
length occupied by a cyclic prefix (CP) of each of the N type-1
OFDM symbols and a fourth time length occupied by a CP of the
type-2 OFDM symbol are greater than or equal to a preset
threshold.
5. The method according to claim 1, wherein a time length of the
time unit is 2 millisecond, .DELTA.f.sub.1=3.75 kHz, and
.DELTA.f.sub.2=15 kHz; and the frame structure is a first frame
structure that comprises seven type-1 OFDM symbols and the GP.
6. The method according to claim 1, wherein a time length of the
time unit is 1 millisecond, .DELTA.f.sub.1=3.75 kHz, and
.DELTA.f.sub.2=15 kHz; and the frame structure is a second frame
structure that comprises three type-1 OFDM symbols and the GP.
7. The method according to claim 1, the sending step comprising:
scheduling, by the base station, the first subcarrier spacing used
by the terminal to send uplink data.
8. A base station, comprising: at least one processor; and a
computer readable storage medium storing programming for execution
by the at least one processor, the programming including
instructions that, when executed by the at least one processor,
facilitate performing a method comprising: indicating a first
subcarrier spacing to a terminal, wherein the first subcarrier
spacing is used by the terminal to determine a frame structure; and
receiving an N type-1 orthogonal frequency division multiplexing
(OFDM) symbols generated by the terminal based on the frame
structure in a time unit, wherein the frame structure indicates
that the N type-1 OFDM symbols and a guard period (GP) are
comprised in the time unit, wherein the first subcarrier spacing of
each type-1 OFDM symbol is .DELTA.f.sub.1, wherein a first time
length of the GP is greater than a second time length occupied by
one type-2 OFDM symbol, wherein a second subcarrier spacing of the
type-2 OFDM symbol is .DELTA.f.sub.2, and wherein .DELTA.f.sub.1 is
unequal to .DELTA.f.sub.2.
9. The base station according to claim 8, wherein N is a positive
integer, and N is a maximum quantity of type-1 OFDM symbols
comprised in the time unit after the second time length occupied by
one type-2 OFDM symbol is subtracted.
10. The base station according to claim 8, wherein the GP is used
to prevent the sent type-1 OFDM symbols and a type-2 OFDM symbol
sent by a second terminal from overlapping on a time-frequency
resource.
11. The base station according to claim 8, wherein both a third
time length occupied by a cyclic prefix (CP) of each of the N
type-1 OFDM symbols and a fourth time length occupied by a CP of
the type-2 OFDM symbol are greater than or equal to a preset
threshold.
12. The base station according to claim 8, wherein a time length of
the time unit is 2 millisecond, .DELTA.f.sub.1=3.75 kHz, and
.DELTA.f.sub.2=15 kHz; and the frame structure is a first frame
structure that comprises seven type-1 OFDM symbols and the GP.
13. The base station according to claim 8, wherein a time length of
the time unit is 1 millisecond, .DELTA.f1=3.75 kHz, and
.DELTA.f2=15 kHz; and the frame structure is a second frame
structure that comprises three type-1 OFDM symbols and the GP.
14. The base station according to claim 8, wherein the programming
further includes instructions to facilitate further performing:
scheduling the first subcarrier spacing used by the terminal to
send uplink data.
15. A non-transitory storage medium comprising instructions that,
when executed by a computer, cause the computer to carry out a
method comprising: indicating a first subcarrier spacing to a
terminal, wherein the first subcarrier spacing is used by the
terminal to determine a frame structure; and receiving an N type-1
orthogonal frequency division multiplexing (OFDM) symbols generated
by the terminal based on the frame structure in a time unit,
wherein the frame structure indicates that the N type-1 OFDM
symbols and a guard period (GP) are comprised in the time unit,
wherein the first subcarrier spacing of each type-1 OFDM symbol is
.DELTA.f.sub.1, wherein a first time length of the GP is greater
than a second time length occupied by one type-2 OFDM symbol,
wherein a second subcarrier spacing of the type-2 OFDM symbol is
.DELTA.f.sub.2, and wherein .DELTA.f.sub.1 is unequal to
.DELTA.f.sub.2.
16. The non-transitory storage medium according to claim 15,
wherein N is a positive integer, and N is a maximum quantity of
type-1 OFDM symbols comprised in the time unit after the second
time length occupied by one type-2 OFDM symbol is subtracted.
17. The non-transitory storage medium according to claim 15,
wherein the GP is used to prevent the sent type-1 OFDM symbols and
a type-2 OFDM symbol sent by a second terminal from overlapping on
a time-frequency resource.
18. The non-transitory storage medium according to claim 15,
wherein a time length of the time unit is 2 millisecond,
.DELTA.f.sub.1=3.75 kHz, and .DELTA.f.sub.2=15 kHz; and the frame
structure is a first frame structure that comprises seven type-1
OFDM symbols and the GP.
19. The non-transitory storage medium according to claim 15,
wherein a time length of the time unit is 1 millisecond,
.DELTA.f1=3.75 kHz, and .DELTA.f2=15 kHz; and the frame structure
is a second frame structure that comprises three type-1 OFDM
symbols and the GP.
20. The non-transitory storage medium according to claim 15,
wherein when the instructions are executed by the computer, cause
the computer to further perform: scheduling the first subcarrier
spacing used by the terminal to send uplink data.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 16/025,697, filed on Jul. 2, 2018, which is a
continuation of International Application No. PCT/CN2016/076404,
filed on Mar. 15, 2016, which claims priority to International
Patent Application No. PCT/CN2015/100357, filed on Dec. 31, 2015.
All of the afore-mentioned patent applications are hereby
incorporated by reference in their entireties.
TECHNICAL FIELD
[0002] The present application relates to the communications field,
and in particular, to a data transmission method and user equipment
in the communications field.
BACKGROUND
[0003] Machine type communication (MTC) is also referred to as
machine-to-machine communication (M2M) or Internet of Things (IOT),
and will become an important application in the communications
field in the future. Future Internet of Things communication may
cover fields such as smart metering, medical inspection and
monitoring, logistics inspection, industrial inspection and
monitoring, vehicle networking, smart community, and wearable
device communication.
[0004] A typical cellular Internet of Things system is narrowband
IOT (NB-IOT). An uplink system bandwidth and a downlink system
bandwidth of the NB-IOT are generally 200 kHz, an operating
bandwidth is 180 kHz, and each guard bandwidth on both sides is 10
kHz. An orthogonal frequency division multiplexing (OFDM)
technology is used for downlink NB-IOT, and twelve subcarriers with
a bandwidth of 15 kHz are multiplexed in a frequency domain. A
single carrier frequency division multiple access (SC-FDMA)
technology is used for uplink NB-IOT. SC-FDMA transmission is first
performing DFT processing on a time-domain signal, mapping a
processed signal onto a subcarrier of a corresponding frequency
resource, and then modulating the signal in an OFDM modulation
manner and sending a modulated signal. By means of such processing,
a peak to average power ratio (PAPR) of a signal of SC-FDMA
transmission is lower, which better helps implement a radio
frequency component on user equipment (UE) such as a mobile
phone.
[0005] The uplink NB-IOT can support two subcarrier spacings of
3.75 kHz and 15 kHz. When the subcarrier spacing of 3.75 kHz is
used, UE supports only single-tone transmission (single-tone
transmission), that is, a bandwidth of a time-domain signal of the
UE is not greater than 3.75 kHz, and after DFT conversion, only one
subcarrier with a subcarrier spacing of 3.75 kHz and in the OFDM
modulation manner is occupied. When the subcarrier spacing of 15
kHz is used, UE may support both single-tone transmission
(single-tone transmission) and multi-tone transmission (multi-tone
transmission).
[0006] When uplink transmit power of UE is limited, a signal
bandwidth of a subcarrier with a subcarrier spacing of 3.75 kHz is
only 1/4 of a bandwidth of a subcarrier with a subcarrier spacing
of 15 kHz. Therefore, a power spectral density of a transmitted
signal of the subcarrier with a subcarrier spacing of 3.75 kHz is
four times that of the subcarrier with a subcarrier spacing of 15
kHz, and better anti-interference and anti-path loss performance
are gained. Therefore, the subcarrier with a subcarrier spacing of
3.75 kHz is more applicable to UE with poor coverage, for example,
UE on a cell edge and even in a basement.
[0007] When a 3.75 kHz uplink subcarrier is embedded and deployed
in a bandwidth resource of legacy Long Term Evolution (LTE), the
following problems exist. On one hand, after transmission with an
uplink subcarrier spacing of 3.75 kHz is introduced, a suitable
time unit needs to be defined to define a physical resource block.
Generally, the time unit is referred to as a subframe. A subframe
time length and a subframe structure need to be defined to make
transmission efficiency of the NB-IOT as high as possible. That is,
as many uplink OFDM symbols as possible are transmitted in each
subframe time length.
[0008] On the other hand, mutual impact between 3.75 kHz uplink
deployment and legacy LTE needs to be minimized. For example, an
uplink channel sounding reference signal (SRS) of UE in legacy LTE
cannot be affected. In addition, because coverage of an NB-IoT user
that uses uplink 3.75 kHz is generally poor, interference from a
channel sounding reference signal of legacy LTE may cause
relatively large impact on SC-FDMA transmission of uplink 3.75 kHz,
which should be avoided. In legacy LTE, a base station may
configure a piece of information srs-SubframeConfig in cell-level
system broadcast information, where the information indicates a
subframe pattern (subframe Pattern) in which an SRS can be sent,
and UE in the cell may send an SRS in only subframes indicated by
the SRS subframe pattern. In legacy LTE, because UE may send an SRS
on only the last OFDM symbol of the indicated subframes, when a
frame structure of the NB-IOT is being designed, such a factor may
be considered, to avoid mutual interference between an OFDM symbol
that is sent by an NB-IOT terminal and that has an uplink
subcarrier spacing of 3.75 kHz and an SRS that may be sent by a
legacy LTE terminal.
[0009] Therefore, the foregoing two factors need to be considered
for a 3.75 kHz uplink frame structure in the NB-IOT.
SUMMARY
[0010] Embodiments of the present application provide a data
transmission method, a subframe structure, and an apparatus, so
that when an NB-IOT system is deployed in an LTE system in an
embedded manner, and when an NB-IOT terminal is sending data, a
channel resource of the legacy LTE system can be adequately
utilized, and a conflict with a legacy LTE SRS can be avoided.
[0011] According to a first aspect, an embodiment of the present
application provides a data transmission method, where the method
includes:
[0012] determining, by a first terminal, a frame structure in a
time unit, where the frame structure indicates that N type-1 OFDM
symbols and a guard period (GP) are included in the time unit, a
subcarrier spacing of each type-1 OFDM symbol is .DELTA.f.sub.1, a
time length of the GP is greater than or equal to a time length
occupied by one type-2 OFDM symbol, a subcarrier spacing of the
type-2 OFDM symbol is .DELTA.f.sub.2, .DELTA.f.sub.1 is unequal to
.DELTA.f.sub.2, and N is a positive integer; and sending, by the
first terminal, the type-1 OFDM symbols according to the frame
structure.
[0013] Therefore, according to the data transmission method in this
embodiment of the present application, a first terminal determines
a frame structure in a time unit, where the frame structure
includes N type-1 orthogonal frequency division multiplexing OFDM
symbols and a GP, and a length of the GP is greater than or equal
to a time length occupied by one OFDM symbol with a subcarrier
spacing of .DELTA.f.sub.2. Therefore, when an NB-IOT system is
deployed in an LTE system in an embedded manner, and when an NB-IOT
terminal is sending data, a channel resource of the legacy LTE
system can be adequately utilized, and a conflict with a legacy LTE
SRS can be avoided.
[0014] According to a second aspect, an embodiment of the present
application provides a frame structure, where the frame structure
indicates that N type-1 orthogonal frequency division multiplexing
OFDM symbols and a guard period GP are included in a time unit, a
subcarrier spacing of each type-1 OFDM symbol is .DELTA.f.sub.1, a
time length of the GP is greater than or equal to a time length
occupied by one type-2 OFDM symbol, a subcarrier spacing of the
type-2 OFDM symbol is .DELTA.f.sub.1, .DELTA.f.sub.1 is unequal to
.DELTA.f.sub.2, and N is a positive integer; and the type-1 OFDM
symbols are sent according to the frame structure.
[0015] Therefore, according to the frame structure in this
embodiment of the present application, a frame structure in a time
unit is designed, where the frame structure includes N type-1
orthogonal frequency division multiplexing OFDM symbols and a GP,
and a length of the GP is greater than or equal to a time length
occupied by one OFDM symbol with a subcarrier spacing of
.DELTA.f.sub.2. Therefore, when an NB-IOT system is deployed in an
LTE system in an embedded manner, and when an NB-IOT terminal is
sending data, a channel resource of the legacy LTE system can be
adequately utilized, and a conflict with a legacy LTE SRS can be
avoided.
[0016] Optionally, the GP is used to prevent the sent type-1 OFDM
symbols and a type-2 OFDM symbol sent by a second terminal from
overlapping on a time-frequency resource.
[0017] Optionally, N is a maximum quantity of carried type-1 OFDM
symbols in the time unit after the time occupied by one type-2 OFDM
symbol is subtracted.
[0018] Optionally, both a time length occupied by a cyclic prefix
(CP) of the type-1 OFDM symbol and a time length occupied by a CP
of the type-2 OFDM symbol are greater than or equal to a preset
threshold.
[0019] Optionally, if a length of the time unit is 2 millisecond
ms, .DELTA.f.sub.1=3.75 kHz, and .DELTA.f.sub.2=15 kHz, the frame
structure is a first frame structure, where the first frame
structure includes seven type-1 OFDM symbols and the GP.
[0020] Optionally, in the time length occupied by the GP, there is
one OFDM symbol, sent by the second terminal, with a subcarrier
spacing of .DELTA.f.sub.2, and a frequency resource corresponding
to the OFDM symbol, sent by the second terminal, with a subcarrier
spacing of .DELTA.f.sub.2 overlaps a frequency resource allocated
to the first terminal in the time unit.
[0021] Optionally, when a sampling rate is 1.92 MHz, the type-1
OFDM symbol includes a symbol sampling point part and a CP part,
where a time length of the symbol sampling point part is 512
T.sub.s, a time length of the CP part is 17 T.sub.s, a time length
occupied by the type-1 OFDM symbol is 529 T.sub.s, and a time
length of T.sub.s is a time length corresponding to each sampling
point at the 1.92 MHz sampling rate; and the length of the GP is
equal to a time length occupied by one type-2 OFDM symbol in a Long
Term Evolution LTE system.
[0022] Optionally, if a length of the time unit is 1 ms,
.DELTA.f.sub.1=3.75 kHz, and .DELTA.f.sub.2=15 kHz, the frame
structure is a second frame structure, where the second frame
structure includes three type-1 OFDM symbols and the GP.
[0023] Optionally, when a sampling rate is 1.92 MHz, the three
type-1 OFDM symbols are respectively a symbol 0, a symbol 1, and a
symbol 2, where the symbol 0 includes a first symbol sampling point
part and a first CP part, a time length of the first symbol
sampling point part is 512 T.sub.s, a time length of the first CP
part is 36 T.sub.s, a time length occupied by the symbol 0 is 548
T.sub.s, and a time length of T.sub.s is a time length
corresponding to each sampling point at the 1.92 MHz sampling rate;
the symbol 1 includes a second symbol sampling point part and a
second CP part, a time length of the second symbol sampling point
part is 512 T.sub.s, a time length of the second CP part is 37
T.sub.s, and a time length occupied by the symbol 1 is 549 T.sub.s;
the symbol 2 is the same as the symbol 0, or the symbol 2 is the
same as the symbol 1; and the length of the GP is equal to a time
length occupied by two type-2 OFDM symbols in LTE.
[0024] According to a third aspect, an embodiment of the present
application provides user equipment, where the user equipment
includes a processor and a transmitter. The processor is configured
to determine a frame structure in a time unit, where the frame
structure indicates that N type-1 orthogonal frequency division
multiplexing OFDM symbols and a guard period GP are included in the
time unit, a subcarrier spacing of each type-1 OFDM symbol is
.DELTA.f.sub.1, a time length of the GP is greater than or equal to
a time length occupied by one type-2 OFDM symbol, a subcarrier
spacing of the type-2 OFDM symbol is .DELTA.f.sub.2, .DELTA.f.sub.1
is unequal to .DELTA.f.sub.2, and N is a positive integer; and the
transmitter is configured to send the type-1 OFDM symbols according
to the frame structure.
[0025] Therefore, according to the user equipment in this
embodiment of the present application, a frame structure in a time
unit is determined. The frame structure includes N type-1 OFDM
symbols with a subcarrier spacing of .DELTA.f.sub.1 and a GP, and a
length of the GP is greater than or equal to a time length occupied
by one OFDM symbol with a subcarrier spacing of .DELTA.f.sub.2.
Therefore, when an NB-IOT system is deployed in an LTE system in an
embedded manner, and when an NB-IOT terminal is sending data, a
channel resource of the legacy LTE system can be adequately
utilized, and a conflict with a legacy LTE SRS can be avoided.
BRIEF DESCRIPTION OF DRAWINGS
[0026] To describe the technical solutions in the embodiments of
the present application more clearly, the following briefly
describes the accompanying drawings required for describing the
embodiments of the present application. Apparently, the
accompanying drawings in the following description show merely some
embodiments of the present application, and a person of ordinary
skill in the art may still derive other drawings from these
accompanying drawings without creative efforts.
[0027] FIG. 1 is a schematic diagram of a communications
system;
[0028] FIG. 2 is a schematic diagram of an application scenario
according to an embodiment of the present application;
[0029] FIG. 3 is a schematic diagram of a frame structure for data
transmission according to an embodiment of the present
application;
[0030] FIG. 4 is a schematic diagram of a frame structure of a 1 ms
subframe of user equipment in a legacy LTE system;
[0031] FIG. 5 is a schematic diagram of a frame structure of a 2 ms
subframe according to an embodiment of the present application;
[0032] FIG. 6 is a schematic diagram of a frame structure of a 1 ms
subframe according to an embodiment of the present application;
[0033] FIG. 7 is a schematic diagram of another frame structure of
a 1 ms subframe according to an embodiment of the present
application;
[0034] FIG. 8 is a schematic diagram of another frame structure of
a 5 ms subframe according to an embodiment of the present
application;
[0035] FIG. 9 is a schematic diagram of another frame structure of
a 2 ms subframe according to an embodiment of the present
application;
[0036] FIG. 10 is a schematic diagram of a configuration of a 2 ms
subframe according to an embodiment of the present application;
[0037] FIG. 11 is another schematic diagram of a configuration of a
2 ms subframe according to an embodiment of the present
application;
[0038] FIG. 12 is a flowchart of a data transmission method
according to an embodiment of the present application;
[0039] FIG. 13 is a structural block diagram of user equipment
according to an embodiment of the present application;
[0040] FIG. 14 is a superframe structure according to an embodiment
of the present application;
[0041] FIG. 15 is another superframe structure according to an
embodiment of the present application; and
[0042] FIG. 16 is still another superframe structure according to
an embodiment of the present application.
DESCRIPTION OF EMBODIMENTS
[0043] The following clearly describes the technical solutions in
the embodiments of the present application with reference to the
accompanying drawings in the embodiments of the present
application. Apparently, the described embodiments are some but not
all of the embodiments of the present application. All other
embodiments obtained by a person of ordinary skill in the art based
on the embodiments of the present application without creative
efforts shall fall within the protection scope of the present
application.
[0044] It should be understood that the technical solutions in the
embodiments of the present application may be applied to various
communications systems, such as a Global System for Mobile
Communications (GSM), a Code Division Multiple Access (CDMA)
system, a Wideband Code Division Multiple Access (WCDMA) system, a
general packet radio service (GPRS), a Long Term Evolution system,
an LTE frequency division duplex (FDD) system, an LTE time division
duplex (TDD) system, a Universal Mobile Telecommunications System
(UMTS), or a Worldwide Interoperability for Microwave Access
(WiMAX) communications system.
[0045] For example, a base station may be a base station (BTS) in
GSM or CDMA, may be a base station (NodeB, "NB" for short) in
WCDMA, or may be an evolved NodeB ("e-NB" or "e-NodeB" for short)
in LTE. This is not limited in the present application.
[0046] For another example, UE may be referred to as a terminal, a
mobile station (MS), or a mobile terminal. The UE may communicate
with one or more core networks by using a radio access network
(RAN). For example, the user equipment may be a mobile phone (also
referred to as a "cellular" phone) or a computer with a mobile
terminal. For example, the user equipment may further be a
portable, pocket-sized, handheld, computer built-in, or in-vehicle
mobile apparatus, which exchanges voice and/or data with the radio
access network.
[0047] It should be further understood that the embodiments of the
present application are described only by using an LTE system as an
example, but the present application is not limited thereto, and
the method and the apparatus in the embodiments of the present
application may be further applied to another communications
system. Similarly, the embodiments of the present application are
also described only by using user equipment in the LTE system as an
example, but the present application is not limited thereto, and
the method and the apparatus in the embodiments of the present
application may be further applied to a base station and user
equipment in another communications system.
[0048] FIG. 1 is a schematic diagram of a communications system. In
FIG. 1, UE may communicate with a core network by using one or more
base stations. For example, in FIG. 1, UE 10a may communicate with
a core network 12 by using a base station 110a on a radio access
network 11a. UE 10b may communicate with the core network 12 by
using the base station 110a on the radio access network 11a or by
using a base station 110b on a radio access network 11b. UE 10c may
communicate with the core network 12 by using the base station 110b
on the radio access network 11b. Further, the UE may communicate
with a public switched telephone network (Public Switched Telephone
Network, PSTN) 13, another network 14, or even the entire Internet
15.
[0049] FIG. 2 is a schematic diagram of an application scenario
according to an embodiment of the present application. As shown in
FIG. 2, a system with a subcarrier spacing of .DELTA.f.sub.2 may be
an existing OFDM system, that is, an existing system. An OFDM
system with a subcarrier spacing of .DELTA.f.sub.1 may be a new
system. The new system is deployed for meeting a new service
requirement. The new system and the existing system may have
different subcarrier spacings, that is,
.DELTA.f.sub.1.noteq..DELTA.f.sub.2.
[0050] It should be noted that values of .DELTA.f.sub.1 and
.DELTA.f.sub.2 are not limited in this embodiment of the present
application. For example, .DELTA.f.sub.1=1/2.times..DELTA.f.sub.2,
.DELTA.f.sub.1=1/4.times..DELTA.f.sub.2, or
.DELTA.f.sub.1=1/6.times.f.sub.2. Generally, when a relationship
between .DELTA.f.sub.1 and .DELTA.f.sub.2 is being designed, a
multiple relationship with a factor of a prime number such as 2, 3,
or 5 is considered. Subsequent embodiments of the present
application are described by mainly using .DELTA.f.sub.1=3.75 kHz
and .DELTA.f.sub.2=15 kHz as an example.
[0051] It should be understood that the new system may be deployed
in a time-frequency resource of the existing system, a bandwidth of
the new system is W.sub..DELTA.f2, and some system resources of the
existing system are used in a manner of frequency division
multiplexing (FDM) or a manner of time division multiplexing (TDM)
and FDM. The existing system is a deployed OFDM system, and when
the new system is being deployed, existing user equipment of the
OFDM system with a subcarrier spacing of .DELTA.f.sub.2 has already
been deployed and used on a live network. The existing user
equipment may not know existence of the OFDM system with a
subcarrier spacing of .DELTA.f.sub.1. Therefore, an OFDM symbol
with a subcarrier spacing of .DELTA.f.sub.2 may be sent in all
resources or some resources of all resources in the entire
bandwidth W.sub..DELTA.f2 of the existing system.
[0052] Therefore, in a frame structure for data transmission in
this embodiment of the present application, when the new system
corresponds to a frame structure of one time unit, a part of time
is reserved as a GP in a particular location of each time unit, for
avoiding interference with the OFDM symbol, sent by the existing
user equipment of the existing system, with a subcarrier spacing of
.DELTA.f.sub.2. For the frame structure, in the time of the GP,
even if the existing user equipment of the existing OFDM system
sends a signal in a resource of the new system, the signal may not
overlap an OFDM symbol, of user equipment of the new system, with a
subcarrier spacing of .DELTA.f.sub.1, thereby avoiding mutual
interference and impact.
[0053] Currently, a sending and receiving structure of an OFDM
system are generally implemented by using an inverse fast Fourier
transformation (IFFT) processing module and a fast Fourier
transformation (FFT) processing module. Assuming that a subcarrier
spacing of the OFDM system is .DELTA.f Hz, and that a sampling rate
S Hz is used, a quantity of FFT points of IFFT processing used by
the OFDM system is S/.DELTA.f, and is defined as X. For a sending
apparatus using OFDM modulation, serial-to-parallel conversion is
performed on a to-be-sent symbol sequence (optionally, sometimes a
zero-adding operation is further required), several zeros are added
to every X symbols output after the serial-to-parallel conversion,
every X symbols are used as a group for IFFT processing,
parallel-to-serial conversion is performed after X output symbols
are obtained, and then, X symbol sampling points on a time domain
are obtained. To resist interference caused by a multipath, after
the IFFT processing, the OFDM modulation sending apparatus may
insert a cyclic prefix including several sampling points (assuming
that a quantity is Y) in front of the X symbol sampling points.
Actually, the cyclic prefix is formed by repeating the last Y
sampling points of the X symbol sampling points and inserting the
last Y sampling points in front of the X symbol sampling points.
Therefore, a final OFDM symbol corresponds to (X+Y) sampling points
on the time domain, and a time corresponding to the OFDM symbol is
a time length of (X+Y).times.T.sub.s seconds, where T.sub.s is a
reciprocal of the sampling rate S Hz. It should be noted that a
time Y.times.T.sub.s corresponding to the cyclic prefix should be
greater than a threshold Threshold.sub.CP, where the threshold is a
length of multipath delay spread of a channel between a receiver
and a sender, and is determined by a communication environment in
which the receiver and the sender are located.
[0054] It should be noted that, because SC-FDMA transmission is
actually performing DFT processing on a time-domain signal, mapping
a processed signal onto a subcarrier of a corresponding frequency
resource, and then modulating the signal in an OFDM modulation
manner and sending a modulated signal. Therefore, in the present
application, terms such as an "OFDM system" and an "OFDM symbol"
are used uniformly for description. However, the content of the
present application is also applicable to a scenario of SC-FDMA
transmission.
[0055] It should be understood that, in this embodiment of the
present application, an OFDM symbol with a subcarrier spacing of
.DELTA.f.sub.1 may be referred to as a type-1 OFDM symbol, and an
OFDM symbol with a subcarrier spacing of .DELTA.f.sub.2 may be
referred to as a type-2 OFDM symbol.
[0056] FIG. 3 is a schematic diagram of a frame structure for data
transmission according to an embodiment of the present application.
The frame structure corresponds to one time unit, and the frame
structure in one time unit may include N OFDM symbols with a
subcarrier spacing of .DELTA.f.sub.1 and a GP, where a length of
the GP may be greater than or equal to a time length occupied by
one OFDM symbol with a subcarrier spacing of .DELTA.f.sub.2,
.DELTA.f.sub.1 is unequal to .DELTA.f.sub.2, and N is a positive
integer.
[0057] Optionally, the time unit may be 1 ms, 2 ms, 4 ms, 5 ms, or
the like.
[0058] It should be noted that the term "frame structure" used in
the present application represents only a symbol structure, a
symbol quantity, and a GP length in one time unit. The term
represents a general concept rather than representing that the time
unit corresponds to a length of one frame. One time unit in the
present application may correspond to a slot (Slot), a subframe
(sub-frame), a frame (Frame), and the like. Frame structures
corresponding to these time units may correspondingly refer to a
slot structure, a subframe structure, and a frame structure. That
is, although the term of frame structure is used in the present
application, the frame structure actually may also refer to a
subframe structure, a slot structure, and the like in general.
[0059] It should be understood that, after a time occupied by N
OFDM symbols with a subcarrier spacing of .DELTA.f.sub.1 is
subtracted from one time unit, a remaining time may be a time
occupied by a GP.
[0060] It should be further understood that, assuming that a time
length of the time unit corresponding to the frame structure is
T.sub.time-unit, a value of N is a maximum quantity of OFDM symbols
with a subcarrier spacing of .DELTA.f.sub.1 that can be carried in
a remaining time of the time unit T.sub.time-unit after the time
that one OFDM symbol with a subcarrier spacing of .DELTA.f.sub.2
needs to occupy is subtracted.
[0061] For example, when a time length of a time unit corresponding
to the frame structure is T.sub.time-unit, a value of N may be a
greatest integer less than or equal to
[.DELTA.f1*(T.sub.time-unit-T.sub.OFDM,.DELTA.f2)], where
T.sub.OFDM,.DELTA.f2 is the time length occupied by one OFDM symbol
with a subcarrier spacing of .DELTA.f.sub.2.
[0062] Optionally, when a data sampling rate is F, a time length
corresponding to each sampling point is T.sub.s, where T.sub.s=1/F.
One OFDM symbol with a subcarrier spacing of .DELTA.f.sub.1may
include FFT.sub..DELTA.f1 symbol sampling points and
CP.sub..DELTA.f1 cyclic prefix (CP) sampling points. One OFDM
symbol with a subcarrier spacing of .DELTA.f.sub.2 may include
FFT.sub..DELTA.f2 symbol sampling points and CP.sub..DELTA.f2
cyclic prefix sampling points; a time length occupied by a cyclic
prefix of the orthogonal frequency division multiplexing OFDM
symbol with a subcarrier spacing of .DELTA.f.sub.1 is
CP.sub..DELTA.f1*Ts, and is not lower than a preset threshold
(Threshold.sub.CP).; A time length occupied by a cyclic prefix of
the OFDM symbol with a subcarrier spacing of .DELTA.f.sub.2 is
CP.sub..DELTA.f2*Ts, and is not lower than the preset threshold
(Threshold.sub.CP).
[0063] Optionally, the GP in the frame structure may be behind or
in the middle of the N OFDM symbols with a subcarrier spacing of
.DELTA.f.sub.1.
[0064] Optionally, the length of the GP in this embodiment of the
present application may be greater than or equal to a time length
of the time length occupied by one OFDM symbol with a subcarrier
spacing of .DELTA.f.sub.2 plus the Threshold.sub.CP, where
.DELTA.f.sub.1 is unequal to .DELTA.f.sub.2, and N is a positive
integer.
[0065] Therefore, according to the frame structure in this
embodiment of the present application, the frame structure includes
N OFDM symbols with a subcarrier spacing of .DELTA.f.sub.1 and a
GP, where a length of the GP is greater than or equal to a time
length occupied by one OFDM symbol with a subcarrier spacing of
.DELTA.f.sub.2. Therefore, when an NB-IOT system is deployed in an
LTE system in an embedded manner, and when NB-IOT user equipment is
sending data, a channel resource of the legacy LTE system can be
adequately utilized, and a conflict with a legacy LTE SRS can be
avoided.
[0066] Optionally, the existing system may be an existing LTE
system, the subcarrier spacing .DELTA.f.sub.2 of the existing
system may be 15 kHz, and the subcarrier spacing .DELTA.f.sub.1 of
the new system may be 3.75 kHz.
[0067] It should be understood that existing UE of the existing LTE
system may send an SRS on the last symbol of OFDM symbols with a
subcarrier spacing of 15 kHz in each 1 ms subframe.
[0068] It should be further understood that, according to an
existing LTE stipulation, existing LTE user equipment may send an
SRS over a full bandwidth in a time sharing manner according to the
full bandwidth or according to a frequency hopping pattern.
Therefore, when UE of the existing LTE system sends an SRS in a
frequency resource of the new system, the SRS may conflict with an
OFDM symbol, sent by UE of the new system, with a subcarrier
spacing of 3.75 kHz, which causes mutual interference.
[0069] Therefore, to avoid interference between the new system and
the SRS of the existing LTE system, in the frame structure for data
transmission in this embodiment of the present application, for
example, a frame structure of a 2 ms subframe, a GP is reserved at
the end of the frame structure, where a length of the GP is greater
than or equal to a length of one OFDM symbol of the existing LTE
system.
[0070] It should be understood that, when a frame boundary of the
new system and a frame boundary of the existing system keep
aligned, the OFDM symbol with a subcarrier spacing of 3.75 kHz of
the new system may not interfere with the SRS sent by the UE of the
existing LTE system. In addition, the frame structure can ensure a
maximum quantity of OFDM symbols, carried in each time unit, with a
subcarrier spacing of 3.75 kHz, to ensure transmission efficiency
of the new system.
[0071] It should be noted that, in the present application, the
"frame boundary" is used to align a boundary of a time unit of the
new system with a boundary of a time unit of the existing system.
In the present application, the frame boundary of the new system
and the frame boundary of the existing system keep aligned, which
may represent that a boundary of a subframe (or a slot, or a frame)
of the new system is aligned with a subframe boundary (or a slot
boundary, or a frame boundary) of the existing system. That is,
although the term of frame boundary is used in the present
application, the frame boundary actually may also refer to a
subframe boundary, a slot boundary, and the like in general.
[0072] It should be understood that a frame structure in a time
unit of 2 ms may be referred to as a "2 ms subframe" for short, a
frame structure in a time unit of 1 ms may be referred to as a "1
ms subframe" for short, and a frame structure in a time unit of 5
ms may be referred to as a "5 ms subframe" for short. The 1 ms
subframe or 2 ms subframe or 5 ms subframe may be uniformly used
for expression subsequently, and no detailed description is
provided.
[0073] FIG. 4 is a schematic diagram of a frame structure of a 1 ms
subframe of UE in a legacy LTE system. A symbol sampling rate in
the frame structure is assumed to be 1.92 MHz, a quantity of points
of an FFT operation is 128, and the frame structure of the 1 ms
subframe may include twelve OFDM symbols with a CP length of 9
T.sub.s and a subcarrier spacing of 15 kHz, and two OFDM symbols
with a CP length of 10 T.sub.s and a subcarrier spacing of 15
kHz.
[0074] It should be understood that the frame structure, shown in
FIG. 4, of the 1 ms subframe of the UE of the legacy LTE system
cannot support an OFDM symbol with a subcarrier spacing of 3.75
kHz.
[0075] It should be understood that the present application is
described by using an assumption of a 1.92 MHz sampling rate.
Actually, when the Nyquist sampling condition is met, different
sampling rates may be used for a same signal. For a same symbol, if
sampling is performed at a different sampling rate (for example, a
sampling rate A times a reference sampling rate), a time length
T.sub.s corresponding to each corresponding sampling point may be
proportionally reduced to 1/A of a time corresponding to each
sampling symbol at the reference sampling rate, and a quantity of
sampling points corresponding to the same symbol is multiplied to A
times a quantity of sampling points at the reference sampling rate.
For an OFDM symbol, a quantity of points of FFT processing
corresponding to the OFDM symbol is also multiplied to A times a
quantity of points of FFT processing at the reference sampling
rate.
[0076] For example, in the schematic diagram, shown in FIG. 4, of
the frame structure of the 1 ms subframe in the legacy LTE system,
if the used sampling rate is assumed to be 1.92 MHz,
T.sub.s=(1/1.92 M)s, a quantity of points of an FFT operation is
128, and the 1 ms subframe may include twelve OFDM symbols with a
CP length of 9 T.sub.s and a subcarrier spacing of 15 kHz, and two
OFDM symbols with a CP length of 10 T.sub.s and a subcarrier
spacing of 15 kHz. If the used sampling rate is 30.72 MHz (16 times
a reference sampling rate of 1.92 MHz), T.sub.s=(1/30.72 M)s, which
is 1/16 of T.sub.s at the reference sampling rate of 1.92 MHz, a
quantity of points of FFT processing is multiplied by 16 times,
that is, 2048, and the LTE 1 ms subframe may include twelve OFDM
symbols with a CP length of (16.times.9) T.sub.s and a subcarrier
spacing of 15 kHz, and two OFDM symbols with a CP length of
(16.times.10) T.sub.s and a subcarrier spacing of 15 kHz. That is,
different sampling rates correspond to different representation
manners for a same frame structure and symbol structure. At
different sampling rates, the quantity of sampling points is
proportionally increased (or decreased), an absolute time of
T.sub.s is proportionally decreased (or increased), and a time
length of a finally represented symbol and a frame structure are
consistent. Representations at different sampling rates are merely
different representations for a frame structure, a symbol
structure, and a GP length in a same time unit.
[0077] Optionally, the frame structure shown in FIG. 3 in this
embodiment of the present application may be applied to the
application scenario shown in FIG. 2. In the scenario, the new
system corresponds to an NB-IOT system, and a subcarrier spacing
.DELTA.f.sub.1 of the new system may be 3.75 kHz. The existing
system corresponds to an existing LTE system, and a subcarrier
spacing of the existing system may be 15 kHz. UE in the NB-IOT
system may use SC-FDMA transmission with a subcarrier spacing of
3.75 kHz on an uplink.
[0078] Optionally, in this embodiment, the frame structure may be a
frame structure of a 2 ms subframe. The frame structure may be a
first frame structure, and may include seven OFDM symbols with a
subcarrier spacing of 3.75 kHz and a GP, where a length of the GP
is greater than or equal to a time length occupied by one OFDM
symbol with a subcarrier spacing of 15 kHz.
[0079] It should be understood that a frame structure of a 2 ms
subframe may be shown in FIG. 5, where the frame structure of the 2
ms subframe shown in FIG. 5 may include seven OFDM symbols with a
subcarrier spacing of 3.75 kHz and a GP located behind the seven
OFDM symbols with a subcarrier spacing of 3.75 kHz, and a length of
the GP is equal to a time length occupied by one OFDM symbol with a
subcarrier spacing of 15 kHz.
[0080] More specifically, structure parameters of the frame
structure of the 2 ms subframe shown in FIG. 5 may be shown in
Table 1. A sampling rate corresponding to the structure parameters
shown in Table 1 is 1.92 MHz. Correspondingly, a time length
T.sub.s corresponding to each sampling point is a reciprocal of the
sampling rate, that is, T.sub.s=(1/1.92 M)s.
[0081] It is understandable that, if another sampling rate is used,
it is required to only perform equal proportion adjustment on a
corresponding sampling point quantity in the table according to the
sampling rate. To avoid repetition, no enumeration is made
herein.
TABLE-US-00001 TABLE 1 Time length (ms) Frame structure 2 Structure
of a symbol with a Duration of a subcarrier spacing of 3.75 kHZ
guard period (GP) FFT.sub..DELTA.fl CP.sub..DELTA.fl Length of
Quantity (128 + 9) T.sub.s an OFDM N of symbol symbols 512 17 529
T.sub.s 7
[0082] FFT.sub..DELTA.f1 represents a quantity of sampling points
corresponding to a symbol sampling point part corresponding to each
OFDM symbol with a subcarrier spacing of .DELTA.f.sub.1, and
CP.sub..DELTA.f1 represents a quantity of sampling points
corresponding to a cyclic prefix CP part of each OFDM symbol with a
subcarrier spacing of .DELTA.f.sub.1. It can be known from a
definition of an OFDM symbol that one OFDM symbol with a subcarrier
spacing of .DELTA.f.sub.1 includes CP.sub..DELTA.f1 CP sampling
points and immediately following FFT.sub..DELTA.f1 symbol sampling
points. Therefore, one OFDM symbol with a subcarrier spacing of
.DELTA.f.sub.1 totally includes
(FFT.sub..DELTA.f1+CP.sub..DELTA.f1) sampling points, and
corresponds to a time length of
(FFT.DELTA.f.sub.1+CP.DELTA.f.sub.1).times.T.sub.s.
[0083] More specifically, the parameters of the frame structure of
the 2 ms subframe shown in Table 1 may include parameters of the
OFDM symbol with a subcarrier spacing of 3.75 kHz and the GP, where
the parameters may include a quantity of FFT points, a CP length of
the OFDM symbol with a subcarrier spacing of 3.75 kHz, a symbol
quantity of OFDM symbols with a subcarrier spacing of 3.75 kHz, a
symbol length of the OFDM symbol with a subcarrier spacing of 3.75
kHz, a time length, and duration of the GP.
[0084] When the sampling rate is 1920 kHz, the frame structure of
the 2 ms subframe includes seven (N=7) OFDM symbols with a
subcarrier spacing of 3.75 kHz, where each OFDM symbol includes 512
symbol sampling points (a corresponding quantity of FFT points is
512) and a CP including 17 sampling points. Therefore, a time
occupied by the CP is 17 T.sub.s, and the whole OFDM symbol
corresponds to 529 sampling points (that is, 512 symbol sampling
points+17 CP sampling points), and an occupied time is a time
length of 529.times.T.sub.s. The length of the GP is equal to the
time length occupied by one OFDM symbol with a subcarrier spacing
of 15 kHz in the existing LTE system, that is, a time length
corresponding to (128+9) sampling points.
[0085] In another example of the frame structure shown in FIG. 5,
structure parameters of the frame structure may be shown in Table
2. A sampling rate corresponding to the frame structure parameters
shown in Table 2 is 1.92 MHz. Correspondingly, a time length
T.sub.s corresponding to each sampling point is a reciprocal of the
sampling rate, that is, T.sub.s=(1/1.92 M)s.
[0086] It is understandable that, if a sampling rate of another
numerical value is used, it is required to only perform equal
proportion adjustment on a corresponding sampling point quantity in
the table according to the sampling rate. To avoid repetition, no
enumeration is made herein.
TABLE-US-00002 TABLE 2 Time length (ms) Frame structure 2 Structure
of a symbol with a Duration of a subcarrier spacing of 3.75 kHZ
guard period (GP) FFT.sub..DELTA.fl CP.sub..DELTA.fl Length of
Quantity [(128 + 9) + 14] an OFDM N of T.sub.s symbol symbols 512
15 527 T.sub.s 7
[0087] FFT.sub..DELTA.f1 represents a quantity of sampling points
corresponding to a symbol sampling point part corresponding to each
OFDM symbol with a subcarrier spacing of .DELTA.f.sub.1, and
C.sub.P.DELTA.f1 represents a quantity of sampling points
corresponding to a cyclic prefix CP part of each OFDM symbol with a
subcarrier spacing of .DELTA.f.sub.1. It can be known from a
definition of an OFDM symbol that one OFDM symbol with a subcarrier
spacing of .DELTA.f.sub.1 includes CP.DELTA.f.sub.1 CP sampling
points and immediately following FFT.sub..DELTA.f1 symbol sampling
points. Therefore, one OFDM symbol with a subcarrier spacing of
.DELTA.f.sub.1 totally includes
(FFT.sub..DELTA.f1+CP.sub..DELTA.f1) sampling points, and
corresponds to a time length of
(FFT.DELTA.f.sub.1+CP.DELTA.f.sub.1).times.T.sub.s.
[0088] More specifically, the parameters of the frame structure in
a time unit of 2 ms shown in Table 2 may include parameters of the
OFDM symbol with a subcarrier spacing of 3.75 kHz and the GP, where
the parameters may include a quantity of FFT points, a CP length of
the OFDM symbol with a subcarrier spacing of 3.75 kHz, a symbol
quantity of OFDM symbols with a subcarrier spacing of 3.75 kHz, a
symbol length of the OFDM symbol with a subcarrier spacing of 3.75
kHz, a time length of a frame, and duration of the GP.
[0089] When the sampling rate is 1920 kHz, the frame structure in a
time unit of 2 ms includes seven (N=7) OFDM symbols with a
subcarrier spacing of 3.75 kHz, where each OFDM symbol includes 512
symbol sampling points (a corresponding quantity of FFT points is
512) and a CP including 15 sampling points. Therefore, a time
occupied by the CP is 15 T.sub.s, and the whole OFDM symbol
corresponds to 527 sampling points (that is, 512 symbol sampling
points+15 CP sampling points), and an occupied time is a time
length of 527.times.T.sub.s. The length of the GP is (128+9+14)
T.sub.s, which is greater than a time length of the time length
occupied by one OFDM symbol with a subcarrier spacing of 15 kHz in
the existing LTE system plus one Threshold.sub.CP.
[0090] It can be seen from Table 1 and Table 2 that, on one hand,
behind the seven OFDM symbols with a subcarrier spacing of 3.75
kHz, there is a GP with a time length of one OFDM symbol with a
subcarrier spacing of 15 kHz. When a frame boundary of the NB-JOT
system and a legacy LTE frame boundary are aligned (as shown in
FIG. 5), because a frame structure of a 2 ms subframe of the NB-JOT
includes a GP, the last symbol of every two LTE frames of legacy
LTE UE does not overlap any OFDM symbol with a subcarrier spacing
of 3.75 kHz of an NB-JOT terminal in the NB-JOT frame in terms of
time. Because an SRS of the existing LTE system is sent on only the
last symbol of OFDM symbols with a subcarrier spacing of 15 kHz of
each LTE 1 ms subframe, the frame structure of the 2 ms subframe in
FIG. 5 of the present application can be introduced to ensure that
the SRS sent in the last subframe of every two subframes in the LTE
system does not interfere with any NB-JOT OFDM symbol with a
subcarrier spacing of 3.75 kHZ.
[0091] Therefore, on a network, a transmission mode of a channel
sounding reference signal in a cell may be appropriately
configured, for example, it is configured that only the second
subframe of two subframes is a subframe in which the channel
sounding reference signal can be sent, to avoid interference
between an NB IOT terminal and an SRS of an existing LTE
terminal.
[0092] On the other hand, in each subframe of the NB JOT, there are
seven OFDM symbol resources in each time unit of 2 ms, which is a
maximum quantity of OFDM symbols with a subcarrier spacing of 3.75
kHz that can be carried in every 2 ms. Therefore, transmission
efficiency of the NB IOT system is ensured. Compared with legacy
LTE, resource efficiency of the NB IOT system is not decreased. In
addition, a CP length of each OFDM symbol with a subcarrier spacing
of 3.75 kHz is 17 T.sub.s, and greater delay spread can be
tolerated.
[0093] Therefore, according to the frame structure for data
transmission in this embodiment of the present application, a frame
structure in a time unit is designed, where the frame structure
includes N OFDM symbols with a subcarrier spacing of .DELTA.f.sub.1
and a GP, and a length of the GP is greater than or equal to a time
length occupied by one OFDM symbol with a subcarrier spacing of
.DELTA.f.sub.2. Therefore, when an NB-IOT system is deployed in an
LTE system in an embedded manner, and when an NB-IOT terminal is
sending data, a channel resource of the legacy LTE system can be
adequately utilized, and a conflict with a legacy LTE SRS can be
avoided.
[0094] It should be understood that the 1 ms subframe already
exists in the existing LTE system, in the present application, the
NB-IOT system is embedded in the LTE system, and UE of the NB-IOT
system may use the foregoing 2 ms subframe.
[0095] Optionally, when the time unit is 1 ms, .DELTA.f.sub.1=3.75
kHz, and .DELTA.f.sub.2=15 kHz, the frame structure may be a second
frame structure, and may include three OFDM symbols with a
subcarrier spacing of 3.75 kHz and a GP, where a length of the GP
is greater than or equal to a time length occupied by one OFDM
symbol with a subcarrier spacing of 15 kHz.
[0096] Optionally, a frame structure of a 1 ms subframe in an
embodiment of the present application may be shown in FIG. 6. The
frame structure may be applied to the application scenario shown in
FIG. 2. In the scenario, the new system corresponds to an NB-IOT
system, and a subcarrier spacing .DELTA.f.sub.1 of the new system
may be 3.75 kHz. The existing system corresponds to an existing LTE
system, and a subcarrier spacing .DELTA.f.sub.2 of the existing
system may be 15 kHz. An NB-IOT terminal may use SC-FDMA
transmission with a subcarrier spacing of 3.75 kHz on an uplink. In
this case, the 1 ms subframe shown in FIG. 6 may be used.
[0097] The frame structure of the 1 ms subframe in this embodiment
of the present application may include three OFDM symbol with a
subcarrier spacing of 3.75 kHz and a GP located behind the three
OFDM symbols with a subcarrier spacing of 3.75 kHz, where a length
of the GP may be greater than or equal to a time length occupied by
one OFDM symbol with a subcarrier spacing of 15 kHz.
[0098] It should be understood that, in the NB-IOT, the frame
structure of the 1 ms subframe may be shown in FIG. 6, and the
frame structure of the 1 ms subframe may include three OFDM symbols
with a subcarrier spacing of 3.75 kHz and a GP located behind the
three OFDM symbols with a subcarrier spacing of 3.75 kHz, where a
length of the GP may be equal to a time length occupied by two OFDM
symbols with a subcarrier spacing of 15 kHz.
[0099] More specifically, parameters of the frame structure of the
1 ms subframe shown in FIG. 6 may be shown in Table 3, and a
sampling rate corresponding to the structure parameters shown in
Table 3 is 1.92 MHz. Correspondingly, a time length T.sub.s
corresponding to each sampling point is a reciprocal of the
sampling rate, that is, T.sub.s=(1/1.92 M)s.
[0100] It is understandable that, if a sampling rate of another
numerical value is used, it is required to only perform equal
proportion adjustment on a corresponding sampling point quantity in
the table according to the sampling rate. To avoid repetition, no
enumeration is made herein.
TABLE-US-00003 TABLE 3 Time length (ms) Frame structure 1
Structures of three symbols with a Duration of a subcarrier spacing
of 3.75 kHz guard period FFT.sub..DELTA.fl CP.sub..DELTA.fl Length
of 2 .times. (128 + 9) an OFDM T.sub.s symbol Structure 512 36 548
T.sub.s of a symbol 0 Structures 512 37 549 T.sub.s of a symbol 1
and a symbol 2
[0101] FFT.sub..DELTA.f1 represents a quantity of sampling points
corresponding to a symbol sampling point part corresponding to each
OFDM symbol with a subcarrier spacing of .DELTA.f.sub.1, and
CP.sub..DELTA.f1 represents a quantity of sampling points
corresponding to a cyclic prefix CP part of each OFDM symbol with a
subcarrier spacing of .DELTA.f.sub.1. It can be known from a
definition of an OFDM symbol that one OFDM symbol with a subcarrier
spacing of .DELTA.f.sub.1 includes CP.sub..DELTA.f1 CP sampling
points and immediately following FFT.sub..DELTA.f1 symbol sampling
points. Therefore, one OFDM symbol with a subcarrier spacing of
.DELTA.f.sub.1 totally includes
(FFT.sub..DELTA.f1+CP.sub..DELTA.f1) sampling points, and
corresponds to a time length of
(FFT.sub..DELTA.f1+CP.sub..DELTA.f1).times.T.sub.s.
[0102] More specifically, the parameters of the 1 ms subframe shown
in Table 3 may include an OFDM symbol 0 with a subcarrier spacing
of 3.75 kHz, an OFDM symbol 1 with a subcarrier spacing of 3.75
kHz, an OFDM symbol 2 with a subcarrier spacing of 3.75 kHz, and a
GP. The parameters for representing the foregoing OFDM symbols and
the GP may include a quantity of FFT points, a CP length of the
OFDM symbol 0 with a subcarrier spacing of 3.75 kHz, CP lengths of
the OFDM symbol 1 with a subcarrier spacing of 3.75 kHz and the
OFDM symbol 2 with a subcarrier spacing of 3.75 kHz, a symbol
length of the OFDM symbol 0 with a subcarrier spacing of 3.75 kHz,
symbol lengths of the OFDM symbol 1 and symbol 2 with a subcarrier
spacing of 3.75 kHz, a time length, a time length of the GP, and so
on.
[0103] When the sampling rate is 1920 kHz, all symbol sampling
point parts of the OFDM symbol 0 with a subcarrier spacing of 3.75
kHz and the symbol 1 and the symbol 2 correspond to 512 sampling
points (a corresponding quantity of FFT.sub..DELTA.f1 points is
512), a quantity of CP sampling points of the OFDM symbol 0 with a
subcarrier spacing of 3.75 kHz is 36, quantities of CP sampling
points of the OFDM symbol 1 with a subcarrier spacing of 3.75 kHz
and the OFDM symbol 2 with a subcarrier spacing of 3.75 kHz are 37,
a first symbol length is 548 T.sub.s, a second symbol length is 549
T.sub.s, and the length of the GP is equal to a time length
occupied by two OFDM symbols with a subcarrier spacing of 15 kHz in
LTE.
[0104] When the sampling rate is 1920 kHz, each 1 ms subframe
includes three (N=3) OFDM symbols with a subcarrier spacing of 3.75
kHz, where each OFDM symbol includes FFT.sub..DELTA.f1 symbol
sampling points (a corresponding quantity of FFT points is
FFT.sub..DELTA.f1) and a cyclic prefix including CP.sub..DELTA.f1
sampling points. Therefore, a time length occupied by the cyclic
prefix is CP.sub..DELTA.f1.times.T.sub.s, and the OFDM symbol with
a subcarrier spacing of 3.75 kHz corresponds to
(FFT.DELTA.f.sub.1+CP.DELTA.f.sub.1) sampling points, and occupies
a time of (FFT.DELTA.f.sub.1+CP.DELTA.f.sub.1).times.T.sub.s.
[0105] Therefore, as shown in table 3, in each 1 ms subframe, the
zeroth OFDM symbol with a subcarrier spacing of 3.75 kHz includes
512 symbol sampling points and a cyclic prefix CP including 36
sampling points. Therefore, a symbol time length of the symbol 0 is
548 T.sub.s. The first or the second OFDM symbol with a subcarrier
spacing of 3.75 kHz includes 512 symbol sampling points and a
cyclic prefix CP including 37 sampling points. Therefore, both a
symbol time length of the symbol 1 and a symbol time length of the
symbol 2 are 549 T.sub.s. A GP length of each 1 ms subframe is
equal to a time length occupied by two OFDM symbols with a
subcarrier spacing of 15 kHz in LTE, that is, a time length
corresponding to 2.times.(128+9) sampling points, that is,
2.times.(128+9).times.T.sub.s, where T.sub.s is a time length
corresponding to each sampling point, and is a reciprocal of the
sampling rate.
[0106] It should be understood that FIG. 6 gives only an example of
the embodiment of Table 3, and another arrangement manner of the
OFDM symbols and the GP is not excluded in the present
application.
[0107] Optionally, when the time unit is 1 ms, .DELTA.f.sub.1=3.75
kHz, and .DELTA.f.sub.2=15 kHz, the frame structure may be a third
frame structure, and may include three OFDM symbols with a
subcarrier spacing of 3.75 kHz and a GP, where a length of the GP
is greater than or equal to a time length occupied by one OFDM
symbol with a subcarrier spacing of 15 kHz.
[0108] Optionally, when the time unit is 2 ms, the frame structure
is a fourth frame structure, where the fourth frame structure is
formed by the second frame structure and/or the third frame
structure.
[0109] Optionally, another frame structure of a 1 ms subframe in
this embodiment of the present application may be shown in FIG. 7.
FIG. 7 is a frame structure of a 1 ms subframe for transmitting
data according to an embodiment of the present application. The 1
ms subframe may be applied to the application scenario shown in
FIG. 2. In the scenario, the new system corresponds to an NB-IOT
system, and a subcarrier spacing .DELTA.f.sub.1 of the new system
may be 3.75 kHz. The existing system corresponds to an existing LTE
system, and a subcarrier spacing .DELTA.f.sub.2 of the existing
system may be 15 kHz. An NB-IOT terminal may use SC-FDMA
transmission with a subcarrier spacing of 3.75 kHz on an uplink. In
this case, the 1 ms subframe shown in FIG. 7 may be used.
[0110] The frame structure of the 1 ms subframe in this embodiment
of the present application may include three OFDM symbols with a
subcarrier spacing of 3.75 kHz and a GP, where a length of the GP
may be a time length occupied by two OFDM symbols with a subcarrier
spacing of 15 kHz, and the GP may be divided into a first GP and a
second GP.
[0111] It should be understood that the frame structure of the 1 ms
subframe in the NB-IOT may be shown in FIG. 7, and the frame
structure of the 1 ms subframe may include three OFDM symbols with
a subcarrier spacing of 3.75 kHz, a first GP, and a second GP,
where both the first GP and the second GP are a time length
occupied by one OFDM symbol with a subcarrier spacing of 15 kHz,
the first GP is located in front of the three OFDM symbols with a
subcarrier spacing of 3.75 kHz, and the second GP is located behind
the three OFDM symbols with a subcarrier spacing of 3.75 kHz.
[0112] More specifically, parameters of the 1 ms subframe shown in
FIG. 7 may be shown in Table 4. A sampling rate corresponding to
the parameters of the 1 ms subframe shown in Table 4 is 1.92 MHz.
Correspondingly, a time length T.sub.s corresponding to each
sampling point is a reciprocal of the sampling rate, that is,
T.sub.s=(1/1.92 M)s.
[0113] It is understandable that, if a sampling rate of another
numerical value is used, it is required to only perform equal
proportion adjustment on a corresponding sampling point quantity in
the table according to the sampling rate. To avoid repetition, no
enumeration is made herein.
TABLE-US-00004 TABLE 4 Time length (ms) Frame structure 1
Structures of three symbols with a Duration of a Duration of a
subcarrier spacing of 3.75 kHz first guard second guard period
period FFT.sub..DELTA.f1 CP.sub..DELTA.f1 Length of an (128 + 10)
T.sub.s (128 + 9) T.sub.s OFDM symbol Symbol 0 512 37 549 T.sub.s
Structures 512 36 548 T.sub.s of a symbol 1 and a symbol 2
[0114] FFT.sub..DELTA.f1 represents a quantity of sampling points
corresponding to a symbol sampling point part corresponding to each
OFDM symbol with a subcarrier spacing of .DELTA.f.sub.1, and
CP.sub..DELTA.f1 represents a quantity of sampling points
corresponding to a cyclic prefix CP part of each OFDM symbol with a
subcarrier spacing of .DELTA.f.sub.1. It can be known from a
definition of an OFDM symbol that one OFDM symbol with a subcarrier
spacing of .DELTA.f.sub.1 includes CP.sub..DELTA.f1 CP sampling
points and immediately following FFT.sub..DELTA.f1 symbol sampling
points. Therefore, one OFDM symbol with a subcarrier spacing of
.DELTA.f.sub.1 totally includes
(FFT.sub..DELTA.f1+CP.sub..DELTA.f1) sampling points, and
corresponds to a time length of
(FFT.sub..DELTA.f1+CP.sub..DELTA.f1).times.T.sub.s.
[0115] More specifically, as shown in Table 4, the frame structure
of the 1 ms subframe may include an OFDM symbol 0 with a subcarrier
spacing of 3.75 kHz, an OFDM symbol 1 with a subcarrier spacing of
3.75 kHz, an OFDM symbol 2 with a subcarrier spacing of 3.75 kHz, a
first GP, and a second GP. The parameters for representing the
foregoing OFDM symbols and the GPs may include a quantity of FFT
points and a CP length of the OFDM symbol 0 with a subcarrier
spacing of 3.75 kHz, quantities of FFT points and CP lengths of the
OFDM symbol 1 with a subcarrier spacing of 3.75 kHz and the symbol
2 with a subcarrier spacing of 3.75 kHz, and time lengths of the
first GP and the second GP.
[0116] When the sampling rate is 1920 kHz, all symbol sampling
point parts of the OFDM symbol 0 with a subcarrier spacing of 3.75
kHz and the symbol 1 and the symbol 2 correspond to 512 sampling
points (a corresponding quantity of FFT.sub..DELTA.f1 points is
512), the CP length of the OFDM symbol 0 with a subcarrier spacing
of 3.75 kHz is 37 T.sub.s, the CP lengths of the OFDM symbol 1 with
a subcarrier spacing of 3.75 kHz and the OFDM symbol 2 with a
subcarrier spacing of 3.75 kHz are 36 T.sub.s, the length of the
symbol 0 is 549 T.sub.s, the lengths of the symbol 1 and the symbol
2 are 548 T.sub.s, the time length of the first GP is 138 T.sub.s,
and the time length of the second GP is 137 T.sub.s.
[0117] When the sampling rate is 1920 kHz, a frame structure of
each 1 ms subframe includes three (N=3) OFDM symbols with a
subcarrier spacing of 3.75 kHz, where each OFDM symbol includes
FFT.sub..DELTA.f1 symbol sampling points (a corresponding quantity
of FFT points is FFT.sub..DELTA.f1) and a cyclic prefix including
CP.sub..DELTA.f1 sampling points. Therefore, a time length occupied
by the cyclic prefix is CP.sub..DELTA.f1.times.T.sub.s, and the
OFDM symbol with a subcarrier spacing of 3.75 kHz corresponds to
(FFT.sub..DELTA.f1+CP.sub..DELTA.f1) sampling points, and occupies
a time of (FFT.sub..DELTA.f1+CP.sub..DELTA.f1).times.T.sub.s.
[0118] Therefore, as shown in Table 4, in each 1 ms subframe, the
zeroth OFDM symbol with a subcarrier spacing of 3.75 kHz includes
512 symbol sampling points and a cyclic prefix CP including 37
sampling points. Therefore, a symbol time length of the symbol 0 is
549 T.sub.s. The first or the second OFDM symbol with a subcarrier
spacing of 3.75 kHz includes 512 symbol sampling points and a
cyclic prefix including 36 sampling points. Therefore, both a
symbol time length of the symbol 1 and a symbol time length of the
symbol 2 are 548 T.sub.s. A length of a first GP of each 1 ms
subframe is equal to a time length occupied by the first OFDM
symbol with a subcarrier spacing of 15 kHz in each 1 ms subframe in
LTE, that is, a time length corresponding to (128+10) sampling
points, that is, (128+10).times.T.sub.s. A length of a second GP of
each 1 ms subframe is equal to a time length occupied by the last
OFDM symbol with a subcarrier spacing of 15 kHz in each 1 ms
subframe in the LTE, that is, a time length corresponding to
(128+9) sampling points, that is, (128+9).times.T.sub.s. T.sub.s is
a time length corresponding to each sampling point, and is a
reciprocal of the sampling rate.
[0119] It should be understood that FIG. 7 gives only an example of
the embodiment of Table 4, and another arrangement manner of the
OFDM symbols and the GP is not excluded in the present
application.
[0120] It should be understood that a 1 ms subframe is defined for
an NB IOT system. When a boundary of the 1 ms subframe is aligned
with a boundary of an existing LTE subframe, it may be found that,
when the NB-IOT system is deployed in an LTE system in an embedded
manner, and an NB-IOT terminal sends a 3.75 kHz OFDM symbol, there
is always no conflict with the last OFDM symbol, sent at the same
time, with a subcarrier spacing of 15 kHz of each 1 ms subframe of
an existing LTE terminal on a system frequency resource, thereby
avoiding mutual interference with an SRS sent by the existing LTE
terminal. In addition, a frame structure of the 1 ms subframe can
carry three OFDM symbols with a subcarrier spacing of 3.75 kHz at
most. Therefore, a design of the frame structure in a time unit of
1 ms is better.
[0121] It should be understood that, in the embodiments of the
present application, sequence numbers of the foregoing OFDM symbols
with a subcarrier spacing of 3.75 kHz are only used to distinguish
different symbols, and do not impose any limitation on
implementation of the embodiments of the present application.
[0122] Optionally, a subframe structure in an embodiment of the
present application may be shown in FIG. 8. FIG. 8 is a subframe
structure for data transmission corresponding to another time unit
according to an embodiment of the present application. The subframe
structure may be applied to the application scenario shown in FIG.
2. In the scenario, the new system corresponds to an NB-IOT system,
and a subcarrier spacing .DELTA.f.sub.1 of the new system may be
3.75 kHz. The existing system corresponds to an existing LTE
system, and a subcarrier spacing .DELTA.f.sub.2 of the existing
system may be 15 kHz. An NB-IOT terminal may use SC-FDMA
transmission with a subcarrier spacing of 3.75 kHz on an uplink. In
this case, the subframe structure shown in FIG. 8 may be used.
[0123] In the subframe structure in this embodiment of the present
application, the time unit may be 5 ms, the time unit may be
defined as a slot or a subframe, and the subframe structure
includes 18 OFDM symbols with a subcarrier spacing of 3.75 kHz and
a GP located behind the 18 OFDM symbols with a subcarrier spacing
of 3.75 kHz, where a length of the GP may be greater than or equal
to a time length occupied by one OFDM symbol with a subcarrier
spacing of 15 kHz.
[0124] More specifically, parameters of the subframe structure
shown in FIG. 8 may be shown in Table 5. A sampling rate
corresponding to the structure parameters shown in Table 5 is 1.92
MHz. Correspondingly, a time length T.sub.s corresponding to each
sampling point is a reciprocal of the sampling rate, that is,
T.sub.s=(1/1.92 M)s.
[0125] It is understandable that, if a sampling rate of another
numerical value is used, it is required to only perform equal
proportion adjustment on a corresponding sampling point quantity in
the table according to the sampling rate. To avoid repetition, no
enumeration is made herein.
TABLE-US-00005 TABLE 5 Time length (ms) Frame structure 5 Structure
of a symbol with a Duration of a subcarrier spacing of 3.75 kHZ
guard period (GP) FFT.sub..DELTA.fl CP.sub..DELTA.fl Length of
Quantity (128 + 22) an OFDM N of T.sub.s symbol symbols 512 13 525
T.sub.s 18
[0126] FFT.sub..DELTA.f1 represents a quantity of sampling points
corresponding to a symbol sampling point part corresponding to each
OFDM symbol with a subcarrier spacing of .DELTA.f.sub.1, and
CP.sub..DELTA.f1 represents a quantity of sampling points
corresponding to a cyclic prefix CP part of each OFDM symbol with a
subcarrier spacing of .DELTA.f.sub.1. It can be known from a
definition of an OFDM symbol that one OFDM symbol with a subcarrier
spacing of .DELTA.f.sub.1 includes CP.sub..DELTA.f1 CP sampling
points and immediately following FFT.sub..DELTA.f1 symbol sampling
points. Therefore, one OFDM symbol with a subcarrier spacing of
.DELTA.f.sub.1 totally includes
(FFT.sub..DELTA.f1+CP.sub..DELTA.f1) sampling points, and
corresponds to a time length of
(FFT.sub..DELTA.f1+CP.sub..DELTA.f1).times.T.sub.s.
[0127] More specifically, the subframe structure in a time unit of
5 ms shown in Table 5 may include OFDM symbols 0 to 17 with a
subcarrier spacing of 3.75 kHz and a GP. The parameters for
representing the foregoing OFDM symbols and the GP may include a
quantity of FFT points, CP lengths of the OFDM symbols 0 to 17 with
a subcarrier spacing of 3.75 kHz, symbol lengths of the OFDM
symbols 0 to 17 with a subcarrier spacing of 3.75 kHz, a subframe
time length, a time length of the GP, and so on.
[0128] When the sampling rate is 1920 kHz, a symbol sampling point
part of each of the OFDM symbols 0 to 17 with a subcarrier spacing
of 3.75 kHz corresponds to 512 sampling points (a corresponding
quantity of FFT.sub..DELTA.f1 points is 512), a quantity of
sampling points of each CP is 13, each symbol length is 525
T.sub.s, and the length of the GP is equal to (128+22) T.sub.s,
which is greater than a time length occupied by one OFDM symbol
with a subcarrier spacing of 15 kHz in LTE, where T.sub.s is a time
length corresponding to each sampling point, and is a reciprocal of
the sampling rate.
[0129] When the sampling rate is 1920 kHz, each 5 ms subframe
includes 18 (N=18) OFDM symbols with a subcarrier spacing of 3.75
kHz, where each OFDM symbol includes FFT.sub..DELTA.f1 symbol
sampling points (a corresponding quantity of FFT points is
FFT.sub..DELTA.f1) and a cyclic prefix including CP.sub..DELTA.f1
sampling points. Therefore, a time length occupied by the cyclic
prefix is CP.sub..DELTA.f1.times.T.sub.s, and the OFDM symbol with
a subcarrier spacing of 3.75 kHz corresponds to
(FFT.sub..DELTA.f1+CP.sub..DELTA.f1) sampling points, and occupies
a time of (FFT.sub..DELTA.f1+CP.sub..DELTA.f1).times.T.sub.s.
[0130] It should be understood that FIG. 8 gives only an example of
the embodiment of Table 5, and another arrangement manner of the
OFDM symbols and the GP is not excluded in the present
application.
[0131] FIG. 5 gives a frame structure of a 2 ms subframe in this
embodiment of the present application. It can be seen from the
frame structure of the 2 ms subframe shown in FIG. 5 that, when a 2
ms subframe is used in an NB IOT system, and when a boundary of the
2 ms subframe of the NB IOT is aligned with a boundary of a 1 ms
subframe in legacy LTE, a GP is set only at the end of the 2 ms
subframe in a frame structure of the 2 ms subframe of the NB IOT,
so as to ensure that only a channel sounding reference signal sent
in the last subframe of every two subframes in the LTE system does
not interfere with any one NB IOT OFDM symbol with a subcarrier
spacing of 3.75 kHZ on a same frequency resource.
[0132] Therefore, on a network, a transmission mode
(srs-SubframeConfig in LTE broadcast information) of a channel
sounding reference signal in a cell needs to be appropriately
configured, for example, it is configured that only the second
subframe of two subframes is a subframe in which the channel
sounding reference signal can be sent, to avoid interference
between an NB IOT terminal and an SRS of an existing LTE terminal.
That is, the frame structure of the 2 ms subframe in FIG. 5 has a
limitation on a legacy LTE SRS configuration.
[0133] It should be understood that a method for resolving the
foregoing SRS configuration limitation is to introduce a frame
structure of a 2 ms subframe shown in FIG. 9 of the present
application. The frame structure of the 2 ms subframe is designed
by connecting two frame structures of a 1 ms subframe in FIG. 6 or
FIG. 7 in series. Without loss of generality, a 2 ms subframe
spliced by using two frame structures of the 1 ms subframe shown in
FIG. 6 may be used as an example. Similarly, the frame structure of
the 2 ms subframe may be spliced by using two frame structure of
the 1 ms subframe shown in FIG. 7.
[0134] For a same time unit, by using the splicing method used in
this embodiment, the frame structure may also be combined by frame
structures corresponding to a time unit of smaller granularity.
[0135] Compared with the 2 ms subframe in FIG. 5, there are seven
OFDM symbol resources in each 2 ms subframe, which is a maximum
quantity of OFDM symbols with a subcarrier spacing of 3.75 kHz that
can be carried in every 2 ms. Therefore, transmission efficiency of
the NB IOT system is ensured. Compared with legacy LTE, resource
efficiency of the NB IOT system is not decreased. When an NB-IOT
system is embedded in a bandwidth of a legacy LTE system, because a
conflict between SC-FDMA transmission with an uplink subcarrier
spacing of 3.75 kHz and an SRS of a legacy LTE terminal needs to be
avoided, there is a certain limitation on an SRS configuration of
the LTE system.
[0136] Further, in the 2 ms subframe structure in FIG. 9, to
prevent a limitation on an SRS transmission subframe configuration
for an existing LTE system that is deployed in a co-existence
manner, a GP is introduced to a frame structure of each 1 ms
subframe. However, only six OFDM symbols with a subcarrier spacing
of 3.75 kHz can be carried in a 2 ms subframe of this type of frame
structure. Compared with the seven symbols that can be carried in
the 2 ms subframe in FIG. 5, efficiency is decreased.
[0137] It should be understood that, relative to a quantity (three)
of symbols with a subcarrier spacing of 3.75 kHZ that are carried
in a frame structure of a 1 ms subframe, a quantity of symbols with
a subcarrier spacing of 3.75 kHz that are carried in each 1 ms
subframe of the frame structure of the 2 ms subframe shown in FIG.
9 is still a maximum quantity of symbols with a subcarrier spacing
of 3.75 kHz that can be carried in the frame structure of a 1 ms
subframe.
[0138] To provide configuration flexibility for an SRS subframe
configuration of an LTE system that is deployed in a co-existence
manner, while ensuring uplink transmission efficiency as far as
possible, in the present application, two types of frame
structures, which are a subframe type 1 (for example, the 2 ms
subframe structure in FIG. 5) and a subframe type 2 (for example,
the 2 ms subframe structure in FIG. 9), are defined separately by
using a 2 ms subframe as an example. Transmission efficiency of the
subframe type 1 is high, and seven OFDM symbols with a subcarrier
spacing of 3.75 kHz are transmitted in each 2 ms subframe. However,
there is a certain limitation on an SRS subframe pattern
configuration of an LTE system that is deployed in a co-existence
manner. For the subframe type 1, only interference from an SRS
symbol in the second subframe of every two 1 ms subframes in the
LTE system can be avoided. The subframe type 2 provides flexibility
for the SRS subframe pattern configuration of the LTE system that
is deployed in a co-existence manner, and may support the legacy
LTE system that is deployed in a co-existence manner, to configure
any 1 ms subframe as a subframe in which an SRS can be sent.
However, transmission efficiency of the subframe type 2 is
decreased, and only six OFDM symbols with a subcarrier spacing of
3.75 kHz can be transmitted in each 2 ms subframe.
[0139] Therefore, to provide configuration flexibility for an SRS
subframe configuration of an LTE system that is deployed in a
co-existence manner, while ensuring uplink transmission efficiency
as far as possible, in an embodiment of the present application, a
base station broadcasts, in system broadcast information of an
NB-IOT system, configuration information about a subframe
transmission mode of the time unit. As shown in FIG. 10, the
configuration information indicates a subframe type transmission
mode used when an NB-IOT terminal in a cell sends uplink
information by using a subcarrier spacing of 3.75 kHz. A
configuration of the subframe type transmission mode matches an SRS
subframe pattern broadcast in the LTE system, so that when the
first subframe of every two consecutive 1 ms LTE subframes may be
used to send an SRS, the NB-IOT uses the subframe type 2 in a
corresponding time. If the first subframe of every two consecutive
1 ms LTE subframes is not used to send an SRS, the NB-IOT uses the
subframe type 1 in a corresponding time of two 1 ms.
[0140] It should be understood that, in the foregoing manner, an
NB-IOT base station may configure the subframe type 1 for the
NB-IOT system as far as possible, to implement higher transmission
efficiency, and when interference from an SRS that may be sent in
the first 1 ms LTE subframe of every two 1 ms LTE subframes needs
to be avoided, the NB-IOT base station may configure the subframe
type 2 for the NB-IOT system as far as possible.
[0141] To provide configuration flexibility for an SRS subframe
configuration of an LTE system that is deployed in a co-existence
manner, while ensuring uplink transmission efficiency as far as
possible, in another embodiment of the present application, a base
station broadcasts, in system broadcast information of an NB-IOT
system, configuration information about a subframe transmission
mode. As shown in FIG. 11, the configuration information indicates
a 2 ms subframe type transmission sequence used when an NB-IOT
terminal in a cell sends uplink information by using 3.75 kHz. In
this embodiment, a configuration of the subframe type transmission
mode matches an SRS subframe pattern broadcast in the LTE
system.
[0142] It should be understood that, in this embodiment, subframe
types of different types are defined by using a subframe in a time
unit of 2 ms as an example, and an SRS subframe pattern
configuration of the co-existing LTE system is flexibly supported
by configuring the subframe type transmission mode. For a subframe
of another time unit such as 1 ms or 5 ms, a similar configuration
manner may be used.
[0143] It should be understood that, as shown in FIG. 11, in this
embodiment of the present application, when only the first subframe
of every two consecutive 1 ms LTE subframes may be used to send an
SRS, and the second subframe is not used to send an SRS, the NB-IOT
system still uses the 2 ms subframe type 1 in a corresponding time;
and only a cyclic shift of the subframe is introduced, so that the
GP is aligned with the last LTE OFDM symbol of the first 1 ms LTE
subframe. If both the first subframe and the second subframe of
every two consecutive 1 ms LTE subframes may be used to send an
SRS, the NB-IOT system uses the 2 ms subframe type 2 in a
corresponding time; if the first subframe of every two consecutive
1 ms LTE subframes is not used to send an SRS, the NB-IOT system
uses the 2 ms subframe type 1 in a corresponding time of two 1
ms.
[0144] It should be understood that, in this manner, an NB-IOT base
station may configure the 2 ms subframe type 1 for the NB-IOT
system as far as possible, to implement higher transmission
efficiency; and when an SRS that may be sent in the first 1 ms LTE
subframe of every two 1 ms LTE subframes needs to be avoided, the
NB-IOT base station may configure the 2 ms subframe type 1 for the
NB-IOT system as far as possible.
[0145] It should be understood that, as shown in FIG. 11, in this
embodiment of the present application, because the cyclic shift is
used for the 2 ms subframe type 1, for a middle OFDM symbol with a
subcarrier spacing of 3.75 kHz of the subframe, sampling points of
the middle OFDM symbol are split on two consecutive parts of one 2
ms subframe and are sent. Upon reception, the base station needs to
perform operations such as FFT demodulation after collecting all
the sampling points at the beginning and the end of the 2 ms
subframe.
[0146] It should be understood that, in this embodiment, subframe
types of different types are defined by using a subframe in a time
unit of 2 ms as an example, and an SRS subframe pattern
configuration of the co-existing LTE system is flexibly supported
by configuring the subframe type transmission mode.
[0147] For the foregoing embodiment in which the configuration
information about the subframe transmission mode of the time unit
is broadcast by using the system information, the subframe type
transmission mode, indicated by the configuration information and
used when uplink information is sent by using 3.75 kHz, matches an
SRS subframe pattern broadcast in the LTE system, so that
transmission is performed according to the frame structure shown in
FIG. 3 in each time unit of 2 ms (without loss of generality, it is
assumed that each 2 ms is a slot). The configuration information of
the subframe type transmission mode makes possible locations of as
many LTE SRSs as possible overlap the GP in the frame structure
shown in FIG. 3. Further, according to a transmission mode
configuration of the LTE SRS, for an LTE SRS location that cannot
overlap the GP part of the frame structure corresponding to the 2
ms slot, user equipment that performs transmission by using a
subcarrier spacing of 3.75 kHz does not perform uplink transmission
on a 3. 75 kHz NB-IoT symbol overlapping with the LTE SRS, or does
not send an uplink 3.75 kHz symbol on only a time location
overlapping with the LTE SRS.
[0148] An SRS configuration of an LTE frame structure Type 1 is
shown in Table 6:
TABLE-US-00006 TABLE 6 Transmission Transmission Subframe srs-Sub-
cycle T.sub.SFC offset .DELTA..sub.SFC carrying frameConfig Binary
(subframe) (subframe) an LTE SRS 0 0000 1 {0} {0, 1, 2, 3, 4, 5, 6,
7, 8, 9} 1 0001 2 {0} {0, 2, 4, 6, 8} 2 0010 2 {1} {1, 3, 5, 7, 9}
3 0011 5 {0} {0, 5} 4 0100 5 {1} {1, 6} 5 0101 5 {2} {2, 7} 6 0110
5 {3} {3, 8} 7 0111 5 {0, 1} {0, 1, 5, 6} 8 1000 5 {2, 3} {2, 3, 7,
8} 9 1001 10 {0} {0} 10 1010 10 {1} {1} 11 1011 10 {2} {2} 12 1100
10 {3} {3} 13 1101 10 {0, 1, 2, 3, {0, 1, 2, 3, 4, 6, 8} 4, 6, 8}
14 1110 10 {0, 1, 2, 3, {0, 1, 2, 3, 4, 5, 6, 8} 4, 5, 6, 8} 15
1111 Reserved Reserved Reserved
[0149] It should be understood that a method for resolving the
foregoing SRS configuration limitation is to introduce a new
superframe structure. The superframe structure herein refers to a
combination manner, on a time domain, of the first frame structure
described above, and may be referred to as a second time unit
superframe structure. The second time unit superframe structure
includes N first frame structures, where N is a positive integer.
In design, a frame structure with a subcarrier spacing of 3.75 kHz
in Table 7 is formed by the 2 ms subframe shown in FIG. 3. When an
SRS transmission symbol overlaps an NB-IoT symbol, an NB-Slot
symbol at the same moment is a blank symbol. The blank symbol
herein refers to that no information, energy, or the like is
transmitted on the symbol.
[0150] In an embodiment, when srs-SubframeConfig is configured as
`0`, `13`, `14`, `7`, or `8` on a network, an SRS is transmitted in
each subframe or most subframes of an LTE radio frame. As shown in
FIG. 14, a start boundary of each first frame structure (NB-Slot)
is aligned with a start boundary of an even-numbered LTE subframe,
and the fourth symbol of each first frame structure (NB-Slot,
narrowband slot) is a blank symbol and is not used for
transmission. One NB-Slot herein is formed by the 2 ms subframe
shown in FIG. 3.
[0151] In an embodiment, when srs-SubframeConfig is configured as
`1` on a network, that is, when an SRS transmission cycle is 2 ms,
the SRS transmission cycle is consistent with a length of an
NB-Slot, and a GP of the NB-Slot right overlaps an LTE SRS
transmission symbol. An SRS is transmitted in an even-numbered
subframe of an LTE radio frame. Therefore, a start boundary of a
first frame structure (NB-Slot) is aligned with a start boundary of
an even-numbered LTE subframe, and all symbols of each first frame
structure (NB-Slot) are used for transmission. One NB-Slot herein
is formed by the 2 ms subframe shown in FIG. 3.
[0152] In an embodiment, when srs-SubframeConfig is configured as
`2` on a network, that is, when an SRS transmission cycle is 2 ms,
the SRS transmission cycle is consistent with a length of an
NB-Slot, and a GP of a first frame structure (NB-Slot) right
overlaps an LTE SRS transmission symbol. An SRS is transmitted in
an odd-numbered subframe of an LTE radio frame. Therefore, a start
boundary of a first frame structure (NB-Slot) is aligned with a
start boundary of an odd-numbered LTE subframe, and all symbols of
each first frame structure (NB-Slot) are used for transmission. One
NB-Slot herein is formed by the 2 ms subframe shown in FIG. 3.
[0153] In an embodiment, when srs-SubframeConfig is configured as
`3` or `9` on a network, an SRS is transmitted in the first
subframe and the sixth subframe of an LTE radio frame, a start
boundary of the second time unit superframe structure is aligned
with a start boundary of the second subframe of the LTE radio
frame, a start boundary of each first frame structure (NB-Slot) is
aligned with a start boundary of an odd-numbered LTE subframe, and
the fourth symbol of the third first frame structure (NB-Slot) is a
blank symbol and is not used for transmission. One first frame
structure (NB-Slot) herein is formed by the 2 ms subframe shown in
FIG. 3.
[0154] In an embodiment, when srs-SubframeConfig is configured as
`9` on a network, an SRS is transmitted in the first subframe of an
LTE radio frame, a start boundary of the second time unit
superframe structure is aligned with a start boundary of the second
subframe of the LTE radio frame, and a start boundary of each first
frame structure (NB-Slot) is aligned with a start boundary of an
odd-numbered LTE subframe. One first frame structure (NB-Slot)
herein is formed by the 2 ms subframe shown in FIG. 3.
[0155] In an embodiment, when srs-SubframeConfig is configured as
`4` or `10` on a network, an SRS is transmitted in the second
subframe and the seventh subframe of an LTE radio frame, a start
boundary of the second time unit superframe structure is aligned
with a start boundary of the first subframe of the LTE radio frame,
a start boundary of each first frame structure (NB-Slot) is aligned
with a start boundary of an even-numbered LTE subframe, and the
fourth symbol of the fourth first frame structure (NB-Slot) is a
blank symbol and is not used for transmission. One first frame
structure (NB-Slot) herein is formed by the 2 ms subframe shown in
FIG. 3.
[0156] In an embodiment, when srs-SubframeConfig is configured as
`10` on a network, an SRS is transmitted in the second subframe of
an LTE radio frame, a start boundary of the second time unit
superframe structure is aligned with a start boundary of the first
subframe of the LTE radio frame, and a start boundary of each first
frame structure (NB-Slot) is aligned with a start boundary of an
even-numbered LTE subframe. One first frame structure (NB-Slot)
herein is formed by the 2 ms subframe shown in FIG. 3.
[0157] In an embodiment, when srs-SubframeConfig is configured as
`5` or `11` on a network, an SRS is transmitted in the third
subframe and the eighth subframe of an LTE radio frame, a start
boundary of the second time unit superframe structure is aligned
with a start boundary of the second subframe of the LTE radio
frame, a start boundary of each first frame structure (NB-Slot) is
aligned with a start boundary of an odd-numbered LTE subframe, and
the fourth symbol of the fourth first frame structure (NB-Slot) is
a blank symbol and is not used for transmission. One first frame
structure (NB-Slot) herein is formed by the 2 ms subframe shown in
FIG. 3.
[0158] In an embodiment, when srs-SubframeConfig is configured as
`11` on a network, an SRS is transmitted in the third subframe of
an LTE radio frame, a start boundary of the second time unit
superframe structure is aligned with a start boundary of the second
subframe of the LTE radio frame, and a start boundary of each first
frame structure (NB-Slot) is aligned with a start boundary of an
odd-numbered LTE subframe. One first frame structure (NB-Slot)
herein is formed by the 2 ms subframe shown in FIG. 3.
[0159] In an embodiment, when srs-SubframeConfig is configured as
`6` or `12` on a network, an SRS is transmitted in the fourth
subframe and the ninth subframe of an LTE radio frame. As shown in
FIG. 14, a start boundary of the second time unit superframe
structure is aligned with a start boundary of the first subframe of
the LTE radio frame, a start boundary of each first frame structure
(NB-Slot) is aligned with a start boundary of an even-numbered LTE
subframe, and the fourth symbol of the fifth first frame structure
(NB-Slot) is a blank symbol and is not used for transmission. One
first frame structure (NB-Slot) herein is formed by the 2 ms
subframe shown in FIG. 3.
[0160] In an embodiment, when srs-SubframeConfig is configured as
`12` on a network, an SRS is transmitted in the fourth subframe of
an LTE radio frame, a start boundary of the second time unit
superframe structure is aligned with a start boundary of the first
subframe of the LTE radio frame, and a start boundary of each first
frame structure (NB-Slot) is aligned with a start boundary of an
even-numbered LTE subframe. One first frame structure (NB-Slot)
herein is formed by the 2 ms subframe shown in FIG. 3.
[0161] Optionally, in each first frame structure (NB-Slot), if
there is a symbol that is a blank symbol and is not used for
transmission, rate matching needs to be performed on data mapped
onto the NB-Slot, and then the data is mapped onto remaining
symbols of the NB-Slot.
[0162] Optionally, configuration information of the seven types of
second time unit superframe structures in Table 7 is indicated by
system information. The system information may be, for example,
NB-IoT system information or LTE system information. The system
information includes 3 bits, which represents eight types of
indications. As shown in the first column of Table 7, `000`
indicates an NB-IoT frame structure with an SRS configuration of
`0`, `13`, `14`, `7`, or `8`. A specific frame structure is
described in the foregoing embodiment, and details are not
described herein. By analogy, as shown in the first column of Table
7, `001` to `110` respectively indicate other NB-IoT frame
structures, and `111` is a reserved bit. In this embodiment, to
reduce a quantity of bits broadcast in the system information, LTE
SRS configurations #3 and #9 are combined. In this scenario, an
NB-IoT terminal sends an uplink 3.75 kHz subcarrier signal
according to only a situation in which a quantity of unused NB-IoT
symbols is greater. That is, as shown in the following figure, a
situation of a related configuration 3 in NB-IoT system broadcast
information may correspond to an LTE SRS configuration #3 or #9. In
this case, NB-IoT information is sent according to the LTE SRS
configuration #3. By analogy, a situation of a related
configuration 4 in NB-IoT system broadcast information may
correspond to LTE SRS configurations #4 and #10. In this case,
NB-IoT information is sent according to the LTE SRS configuration
#4. A situation of a related configuration 5 in NB-IoT system
broadcast information may correspond to LTE SRS configurations #5
and #11. In this case, NB-IoT information is sent according to the
LTE SRS configuration #5. A situation of a related configuration 6
in NB-IoT system broadcast information may correspond to LTE SRS
configurations #6 and #12. In this case, NB-IoT information is sent
according to the LTE SRS configuration #6. A situation of a related
configuration 0 in NB-IoT system broadcast information may
correspond to LTE SRS configurations #0, #13, #14, #7, and #8. In
this case, NB-IoT information is sent according to the LTE SRS
configuration #0.
[0163] Optionally, in this embodiment, to reduce a quantity of bits
broadcast in the system information, LTE SRS configurations #0,
#13, #14, #7, and #8 are combined. In this case, NB-IoT information
is sent according to the LTE SRS configuration #0, LTE SRS
configurations #1, #4, #6, #10, and #12 are combined. In this case,
a start boundary of the second time unit superframe structure is
aligned with a start boundary of the first subframe of an LTE radio
frame, a start boundary of each first frame structure (NB-Slot) is
aligned with a start boundary of an even-numbered LTE subframe, and
the fourth symbol of each of the fourth and the fifth first frame
structures (NB-Slot) is a blank symbol and is not used for
transmission. One first frame structure (NB-Slot) herein is formed
by the 2 ms subframe shown in FIG. 3. LTE SRS configurations #2,
#3, #5, #9, and #11 are combined. In this case, a start boundary of
the second time unit superframe structure is aligned with a start
boundary of the second subframe of an LTE radio frame, a start
boundary of each first frame structure (NB-Slot) is aligned with a
start boundary of an odd-numbered LTE subframe, and the fourth
symbol of each of the third and the fourth first frame structures
(NB-Slot) is a blank symbol and is not used for transmission. The
foregoing combination information may be indicated by 2 bit
information in NB-IoT system information or LTE system
information.
[0164] Optionally, the NB-IoT frame structure configuration
information is indicated by system information. The system
information may be, for example, NB-IoT system information or LTE
system information. The system information includes 4 bits, which
represents 16 types of indications. The 16 types of indications
herein respectively correspond to 16 types of configurations of
srs-SubframeConfig, and corresponding NB-IoT frame structures are
described in the foregoing embodiment, and details are not
described herein.
[0165] Optionally, a demodulation reference signal in an NB-IoT
uplink subframe is transmitted on the third or the fifth symbol of
each NB-Slot.
[0166] The frame structure with a subcarrier spacing of 15 kHz in
Table 7 is similar to a legacy LTE frame structure. In this case, a
symbol length in the NB-Slot is equal to a legacy LTE symbol. A
boundary of the first NB-Slot is aligned with a boundary of the
first LTE subframe, and the same applies to subsequent NB-Slots. On
a symbol with SRS transmission configured on the network, an
NB-Slot symbol at the same moment is not used for transmission.
TABLE-US-00007 Configuration# NB-IoT frame NB-IoT frame regarding
the Corresponding structure structure field broadcasted to LTE (for
3.75 kHz (for 15 kHz in NB-IoT srs-SubframeConfig# transmission)
transmission) 0 #0 (a cycle of 1 ms), A start boundary of an A
start boundary of an #13, #14, #7, #8 NB-Slot is aligned NB-Slot #0
is aligned with a boundary of an with a boundary of an
even-numbered LTE LTE subframe #0. subframe. The last symbol of A
middle symbol of each 1 ms NB-IoT each of all five subframe is a
blank NB-Slots is a blank symbol. symbol. 1 #1 (a cycle of 2 ms) A
start boundary of an A start boundary of an NB-Slot is aligned
NB-Slot #0 is aligned with a boundary of an with a boundary of an
even-numbered LTE LTE subframe #0. subframe. The last symbol of All
NB-IoT symbols each of 1 ms NB-IoT are used for subframes #0, #2,
#4, transmission. #6, and #8 is a blank symbol. 2 #2 (a cycle of 2
ms) A start boundary of an A start boundary of an NB-Slot is
aligned NB-Slot #0 is aligned with a boundary of an with a boundary
of an odd-numbered LTE LTE subframe #0. subframe. The last symbol
of All NB-IoT symbols each of 1 ms NB-IoT are used for subframes
#1, #3, #5, transmission. #7, and #9 is a blank symbol. 3 #3 (a
cycle of 5 ms), A start boundary of an A start boundary of an #9 (a
cycle of 10 ms) NB-Slot #0 is aligned NB-Slot #0 is aligned with a
boundary of an with a boundary of an LTE subframe #1. LTE subframe
#0. A middle symbol of The last symbol of an NB-Slot #2 is a each
of 1 ms NB-IoT blank symbol. subframes #0 and #5 is a blank symbol.
4 #4 (a cycle of 5 ms) A start boundary of an A start boundary of
an #10 (a cycle of 10 ms) NB-Slot #0 is aligned NB-Slot #0 is
aligned with a boundary of an with a boundary of an LTE subframe
#0. LTE subframe #0. A middle symbol of The last symbol of an
NB-Slot #3 is a each of 1 ms NB-IoT blank symbol. subframes #1 and
#6 is a blank symbol. 5 #5 (a cycle of 5 ms) A start boundary of an
A start boundary of an #11 (a cycle of 10 ms) NB-Slot #0 is aligned
NB-Slot #0 is aligned with a boundary of an with a boundary of an
LTE subframe #1. LTE subframe #0. A middle symbol of The last
symbol of an NB-Slot #3 is a each of 1 ms NB-IoT blank symbol.
subframes #2 and #7 is a blank symbol. 6 #6 (a cycle of 5 ms) A
start boundary of an A start boundary of an #12 (a cycle of 10 ms)
NB-Slot #0 is aligned NB-Slot #0 is aligned with a boundary of an
with a boundary of an LTE subframe #0. LTE subframe #0. A middle
symbol of The last symbol of an NB-Slot #4 is a each of 1 ms NB-IoT
blank symbol. subframes #3 and #8 is a blank symbol. 7 reserved No
LTE SRS No LTE SRS configured configured
[0167] The foregoing describes in detail the frame structure for
data transmission according to the embodiments of the present
application with reference to FIG. 3 to FIG. 9, and the following
describes a data transmission method according to an embodiment of
the present application.
[0168] FIG. 12 is a flowchart of a data transmission method
according to an embodiment of the present application. The method
may be applied to the application scenario shown in FIG. 2. The
method is executed by uplink UE with a subcarrier spacing is
.DELTA.f.sub.1, and the uplink user equipment may be first UE in an
NB-IOT system.
[0169] S110. Determine a frame structure in a time unit, where the
frame structure includes N OFDM symbols with a subcarrier spacing
of .DELTA.f.sub.1 and a GP, a length of the GP is greater than or
equal to a time length occupied by one OFDM symbol with a
subcarrier spacing of .DELTA.f.sub.2, .DELTA.f.sub.1 is unequal to
.DELTA.f.sub.2, and N is a positive integer.
[0170] S120. Send the OFDM symbols with a subcarrier spacing of
.DELTA.f.sub.1 according to the frame structure.
[0171] Specifically, in S110, when a time length of the time unit
corresponding to the frame structure is T.sub.time-unit, a value of
N is a maximum quantity of orthogonal frequency division
multiplexing OFDM symbols with a subcarrier spacing of
.DELTA.f.sub.1 that can be carried in the time unit
T.sub.time-unit, after the time that needs to be occupied by one
OFDM symbol with a subcarrier spacing of .DELTA.f.sub.2 is
subtracted.
[0172] Optionally, that the first UE determines a frame structure
in a time unit may be that the first UE determines the frame
structure in the time unit according to scheduling of a base
station. For example, for NB-IoT UE, the base station may indicate
an uplink subcarrier spacing used by the UE when scheduling UE
transmission, and a different subcarrier spacing corresponds to a
different frame structure. Alternatively, that the first UE
determines a frame structure in a time unit may be that the first
UE determines, according to a configuration of a base station or a
network, which frame structure is used in the time unit.
[0173] For example, when a time length of a time unit corresponding
to the frame structure is T.sub.time-unit, a value of N may be a
greatest integer less than or equal to
[.DELTA.f1*(T.sub.time-unit-T.sub.OFDM,.DELTA.f2)], where
T.sub.OFDM,.DELTA.f2 is the time length occupied by one OFDM symbol
with a subcarrier spacing of .DELTA.f.sub.2.
[0174] It should be understood that, after the N OFDM symbols with
a subcarrier spacing of .DELTA.f.sub.1 are subtracted from a time
unit, a remaining time is a time occupied by the GP.
[0175] Optionally, the GP may be behind the N orthogonal frequency
division multiplexing OFDM symbols with a subcarrier spacing of
.DELTA.f.sub.1, that is, the GP is at the end of the time unit.
[0176] It should be further understood that, in the time occupied
by the GP, there may be at least one OFDM symbol, sent by second
UE, with a subcarrier spacing of .DELTA.f.sub.2.
[0177] It should be further understood that the first UE may be UE
in the new system in FIG. 2, and the second UE may be existing UE
of an existing system. The first UE may send an OFDM symbol of the
new system, and because the second UE does not know existence of
the new system, the second UE may send an OFDM symbol of the
existing system in a resource allocated to the new system.
[0178] Therefore, according to the data transmission method in this
embodiment of the present application, a frame structure in a time
unit is designed, where the frame structure includes N OFDM symbols
with a subcarrier spacing of .DELTA.f.sub.1 and a GP, and a length
of the GP is greater than or equal to a time length occupied by one
OFDM symbol with a subcarrier spacing of .DELTA.f.sub.2. When a new
system is an NB-IOT system, and is deployed in an existing system
(an LTE system) in an embedded manner, and when NB-IOT UE is
sending data, resources can be adequately utilized, and a conflict
with a legacy LTE SRS can be avoided.
[0179] Further, the first UE may be UE of the new system, and a
subcarrier spacing of the UE may be 3.75 kHz, and the second UE may
be existing LTE UE. The second UE may send an SRS on the last OFDM
symbol of some 1 ms LTE subframes according to an LTE
configuration.
[0180] It should be further understood that, according to an
existing LTE stipulation, the second UE may send an SRS over a full
bandwidth in a time sharing manner according to the full bandwidth
or according to a frequency hopping pattern. Therefore, when the
second UE sends an SRS in a frequency resource of the new system,
the SRS may conflict with a symbol sent by the first UE, which
causes mutual interference.
[0181] Therefore, according to the data transmission method in this
embodiment of the present application, the first UE does not send,
in the GP, an OFDM symbol with a subcarrier spacing of
.DELTA.f.sub.1, and the GP is greater than or equal to a length of
one existing LTE OFDM symbol, thereby avoiding interference of an
OFDM symbol with a subcarrier spacing of .DELTA.f.sub.2 (for
example, an SRS symbol) sent by the first UE and the second UE in
the time of the GP.
[0182] In the data transmission method of this embodiment,
optionally, the new system corresponds to an NB-IOT system, SC-FDMA
transmission may be used on an uplink, and a subcarrier spacing
.DELTA.f.sub.1 of the new system may be 3.75 kHz. The existing
system corresponds to an existing LTE system, and a subcarrier
spacing .DELTA.f.sub.2 of the existing system may be 15 kHz.
[0183] Optionally, a frame structure of a 2 ms subframe may include
seven OFDM symbols with a subcarrier spacing of 3.75 kHz and a GP,
where a length of the GP may be greater than or equal to a time
length occupied by one OFDM symbol with a subcarrier spacing of 15
kHz.
[0184] It should be understood that the frame structure of the 2 ms
subframe in the NB-IOT may be shown in FIG. 5, and the frame
structure may include seven OFDM symbols with a subcarrier spacing
of 3.75 kHz and a GP located behind the seven OFDM symbols with a
subcarrier spacing of 3.75 kHz, where a length of the GP may be
equal to a time length occupied by one OFDM symbol with a
subcarrier spacing of 15 kHz.
[0185] More specifically, parameters of the 2 ms subframe may be
shown in Table 1, and details are not described herein.
[0186] Therefore, according to the data transmission method in this
embodiment of the present application, a frame structure in a time
unit is designed, where the frame structure includes N OFDM symbols
with a subcarrier spacing of .DELTA.f.sub.1 and a GP, and a length
of the GP is greater than or equal to a time length occupied by one
OFDM symbol with a subcarrier spacing of .DELTA.f.sub.2. Therefore,
when an NB-IOT system is deployed in an LTE system in an embedded
manner, and when NB-IOT UE is sending data, a conflict with a
legacy LTE SRS can always be avoided, and time-frequency resources
can be adequately utilized.
[0187] In the data transmission method of this embodiment,
optionally, the new system corresponds to an NB-IOT system, SC-FDMA
transmission may be used on an uplink, and a subcarrier spacing
.DELTA.f.sub.1 of the new system may be 3.75 kHz. The existing
system corresponds to an existing LTE system, and a subcarrier
spacing .DELTA.f.sub.2 of the existing system may be 15 kHz.
[0188] Optionally, a frame structure of a 1 ms subframe includes
three OFDM symbols with a subcarrier spacing of 3.75 kHz and a GP
located behind the three OFDM symbols with a subcarrier spacing of
3.75 kHz, where a length of the GP may be a time length occupied by
two OFDM symbols with a subcarrier spacing of 15 kHz.
[0189] It should be understood that, in the NB-IOT, the frame
structure of the 1 ms subframe may be shown in FIG. 6, and the
frame structure may include three OFDM symbols with a subcarrier
spacing of 3.75 kHz and a GP located behind the three OFDM symbols
with a subcarrier spacing of 3.75 kHz, where a length of the GP may
be equal to a time length occupied by two OFDM symbols with a
subcarrier spacing of 15 kHz.
[0190] More specifically, parameters of the 1 ms subframe may be
shown in Table 3, and details are not described herein.
[0191] Therefore, according to the data transmission method in this
embodiment of the present application, a frame structure in a time
unit is designed, where the frame structure includes N OFDM symbols
with a subcarrier spacing of .DELTA.f.sub.1 and a GP, and a length
of the GP is greater than or equal to a time length occupied by one
OFDM symbol with a subcarrier spacing of .DELTA.f.sub.2. Therefore,
when an NB-IOT system is deployed in an LTE system in an embedded
manner, and when NB-IOT UE is sending data, a conflict with a
legacy LTE SRS can always be avoided, and time-frequency resources
can be adequately utilized.
[0192] In the data transmission method of this embodiment,
optionally, the new system corresponds to an NB-IOT system, SC-FDMA
transmission may be used on an uplink, and a subcarrier spacing
.DELTA.f.sub.1 of the new system may be 3.75 kHz. The existing
system corresponds to an existing LTE system, and a subcarrier
spacing .DELTA.f.sub.2 of the existing system may be 15 kHz.
[0193] Optionally, a frame structure of a 1 ms subframe includes
three OFDM symbols with a subcarrier spacing of 3.75 kHz, a first
GP, and a second GP.
[0194] It should be understood that, in the NB-IOT, the frame
structure of the 1 ms subframe may be shown in FIG. 7, and the
frame structure may include three OFDM symbols with a subcarrier
spacing of 3.75 kHz, a first GP, and a second GP, where both the
first GP and the second GP are a time length occupied by one OFDM
symbol with a subcarrier spacing of 15 kHz, the first GP is located
in front of the three OFDM symbols with a subcarrier spacing of
3.75 kHz, and the second GP is located behind the three OFDM
symbols with a subcarrier spacing of 3.75 kHz.
[0195] More specifically, parameters of the 1 ms subframe may be
shown in Table 4, and details are not described herein.
[0196] In the data transmission method of this embodiment,
optionally, the new system corresponds to an NB-IOT system, SC-FDMA
transmission may be used on an uplink, and a subcarrier spacing
.DELTA.f.sub.1 of the new system may be 3.75 kHz. The existing
system corresponds to an existing LTE system, and a subcarrier
spacing .DELTA.f.sub.2 of the existing system may be 15 kHz. In
this embodiment, a design of a frame structure of a 2 ms subframe
is provided, for example, a frame structure of a 2 ms subframe
shown in FIG. 9. The frame structure of the 2 ms subframe may be
designed by connecting two frame structures of a 1 ms subframe in
FIG. 6 or FIG. 7 in series. Optionally, a 2 ms subframe spliced by
using two frame structures of the 1 ms subframe shown in FIG. 6 may
be used as an example. The 2 ms subframe may also be spliced by
using two 1 ms subframes shown in FIG. 7.
[0197] It should be understood that one to two OFDM symbols with a
subcarrier spacing of 15 kHz are reserved in each uplink frame
structure with a subcarrier spacing of 3.75 kHz, and may be used to
avoid a conflict with the legacy LTE SRS. However, if the base
station knows that no user equipment sends an SRS on a TTI on a
physical resource module (PRB) on which an NB-IOT physical resource
is located, the base station may schedule uplink NB-IOT UE (that
is, third UE) with a subcarrier spacing of 15 kHz to send one to
two symbols with a subcarrier spacing of 15 kHz to the base station
in the time of the GP, to carry uplink data, a pilot signal, or the
like of the third UE.
[0198] Optionally, when the time of the GP does not include an
uplink SRS sent by the second UE, the GP may be used to send an
OFDM symbol with a subcarrier spacing of .DELTA.f.sub.2 by the
third UE.
[0199] For example, for the GP in the 1 ms subframe, if no legacy
LTE UE sends an SRS in a transmission time spacing, the base
station may instruct next scheduled uplink UE with an uplink
multi-subcarrier or single-carrier subcarrier spacing of 15 kHz to
carry uplink data of the uplink UE with a subcarrier spacing of 15
kHz by using a time-frequency resource of the GP in the 1 ms
subframe.
[0200] It should be understood that the base station may send an
indication message by using a physical downlink control channel
(PDCCH), where the indication message may instruct NB-IOT user
equipment with a subcarrier spacing of 15 kHz to carry data by
using a time-frequency resource of the GP when sending the data to
the base station.
[0201] Therefore, according to the data transmission method in this
embodiment of the present application, a frame structure in a time
unit is designed, where the frame structure includes N orthogonal
frequency division multiplexing OFDM symbols with a subcarrier
spacing of .DELTA.f.sub.1 and a guard period GP, and a length of
the GP is greater than or equal to a time length occupied by one
OFDM symbol with a subcarrier spacing of .DELTA.f.sub.2. Therefore,
when an NB-IOT system is deployed in an LTE system in an embedded
manner, and when NB-IOT UE is sending data, a resource of the
legacy LTE system can be adequately utilized, and a conflict with a
legacy LTE SRS can be avoided.
[0202] It should be understood that one to two OFDM symbols with a
subcarrier spacing of 15 kHz are reserved in each uplink frame
structure with a subcarrier spacing of 3.75 kHz, which may be a
first GP or a second GP or a GP, and may be used to avoid a
conflict with the legacy LTE SRS. However, if the base station
knows that no SRS is sent on an LTE frame structure on a PRB on
which an NB-IOT physical resource is located, the base station may
schedule uplink NB-IOT user equipment with a subcarrier spacing of
15 kHz to use one to two spare OFDM symbols with a subcarrier
spacing of 15 kHz in a frame structure of uplink user equipment
with a subcarrier spacing of 3.75 kHz when sending data to the base
station, that is, may adequately utilize the first GP or the second
GP or the GP of an uplink with an NB-IOT 3.75 Hz subcarrier spacing
to carry information of the uplink NB-IOT user equipment with a
subcarrier spacing of 15 kHz.
[0203] For example, the 1 ms subframe in FIG. 7 may include a first
GP and a second GP, and if no legacy LTE user equipment sends an
SRS on a frequency resource occupied by the NB IOT UE in the 1 ms
time unit, the base station may instruct another user equipment to
send a symbol with an uplink multi-subcarrier or single-carrier
subcarrier spacing of 15 kHz, to carry uplink data of the uplink
user equipment.
[0204] It should be understood that the base station may send an
indication message by using a PDCCH, where the indication message
may instruct an NB-IOT user equipment with a subcarrier spacing of
15 kHz to carry data by using the first GP and/or the second GP
when sending the data to the base station.
[0205] Therefore, according to the data transmission method in this
embodiment of the present application, a frame structure in a time
unit is designed, where the frame structure includes N orthogonal
frequency division multiplexing OFDM symbols with a subcarrier
spacing of .DELTA.f.sub.1 and a guard period GP, and a length of
the GP is greater than or equal to a time length occupied by one
OFDM symbol with a subcarrier spacing of .DELTA.f.sub.2. Therefore,
when an NB-IOT system is deployed in an LTE system in an embedded
manner, and when NB-IOT UE is sending data, a resource of the
legacy LTE system can be adequately utilized, and a conflict with a
legacy LTE SRS can be avoided.
[0206] Based on new superframe structures provided in FIG. 14 to
FIG. 16, an embodiment of the present application provides another
data transmission method, including:
[0207] determining a superframe structure in a second time unit,
where the superframe structure includes N first frame structures,
and N is a positive integer; and
[0208] sending an OFDM symbol with a subcarrier spacing of
.DELTA.f.sub.1 according to the frame structure.
[0209] Specifically, when a channel sounding reference signal (SRS,
Sounding Reference Signal) subframe configuration item
srs-SubframeConfig is configured as `0`, `13`, `14`, `7`, or `8` on
a network, an SRS is transmitted in each subframe or most subframes
of an LTE radio frame. As shown in FIG. 14, a start boundary of
each first frame structure (NB-Slot) is aligned with a start
boundary of an even-numbered LTE subframe, and the fourth symbol of
each first frame structure (NB-Slot, narrowband slot) is a blank
symbol and is not used for transmission. One NB-Slot herein is
formed by the 2 ms subframe shown in FIG. 3.
[0210] When srs-SubframeConfig is configured as `1` on a network,
that is, when an SRS transmission cycle is 2 ms, the SRS
transmission cycle is consistent with a length of an NB-Slot, and a
GP of the NB-Slot right overlaps an LTE SRS transmission symbol. An
SRS is transmitted in an even-numbered subframe of an LTE radio
frame. Therefore, a start boundary of a first frame structure
(NB-Slot) is aligned with a start boundary of an even-numbered LTE
subframe, and all symbols of each first frame structure (NB-Slot)
are used for transmission. One NB-Slot herein is formed by the 2 ms
subframe shown in FIG. 3.
[0211] When srs-SubframeConfig is configured as `2` on a network,
that is, when an SRS transmission cycle is 2 ms, the SRS
transmission cycle is consistent with a length of an NB-Slot, and a
GP of a first frame structure (NB-Slot) right overlaps an LTE SRS
transmission symbol. An SRS is transmitted in an odd-numbered
subframe of an LTE radio frame. Therefore, a start boundary of a
first frame structure (NB-Slot) is aligned with a start boundary of
an odd-numbered LTE subframe, and all symbols of each first frame
structure (NB-Slot) are used for transmission. One NB-Slot herein
is formed by the 2 ms subframe shown in FIG. 3.
[0212] When srs-SubframeConfig is configured as `3` or `9` on a
network, an SRS is transmitted in the first subframe and the sixth
subframe of an LTE radio frame, a start boundary of the second time
unit superframe structure is aligned with a start boundary of the
second subframe of the LTE radio frame, a start boundary of each
first frame structure (NB-Slot) is aligned with a start boundary of
an odd-numbered LTE subframe, and the fourth symbol of the third
first frame structure (NB-Slot) is a blank symbol and is not used
for transmission. One first frame structure (NB-Slot) herein is
formed by the 2 ms subframe shown in FIG. 3.
[0213] When srs-SubframeConfig is configured as `9` on a network,
an SRS is transmitted in the first subframe of an LTE radio frame,
a start boundary of the second time unit superframe structure is
aligned with a start boundary of the second subframe of the LTE
radio frame, and a start boundary of each first frame structure
(NB-Slot) is aligned with a start boundary of an odd-numbered LTE
subframe. One first frame structure (NB-Slot) herein is formed by
the 2 ms subframe shown in FIG. 3.
[0214] When srs-SubframeConfig is configured as `4` or `10` on a
network, an SRS is transmitted in the second subframe and the
seventh subframe of an LTE radio frame, a start boundary of the
second time unit superframe structure is aligned with a start
boundary of the first subframe of the LTE radio frame, a start
boundary of each first frame structure (NB-Slot) is aligned with a
start boundary of an even-numbered LTE subframe, and the fourth
symbol of the fourth first frame structure (NB-Slot) is a blank
symbol and is not used for transmission. One first frame structure
(NB-Slot) herein is formed by the 2 ms subframe shown in FIG.
3.
[0215] When srs-SubframeConfig is configured as `10` on a network,
an SRS is transmitted in the second subframe of an LTE radio frame,
a start boundary of the second time unit superframe structure is
aligned with a start boundary of the first subframe of the LTE
radio frame, and a start boundary of each first frame structure
(NB-Slot) is aligned with a start boundary of an even-numbered LTE
subframe. One first frame structure (NB-Slot) herein is formed by
the 2 ms subframe shown in FIG. 3.
[0216] When srs-SubframeConfig is configured as `5` or `11` on a
network, an SRS is transmitted in the third subframe and the eighth
subframe of an LTE radio frame, a start boundary of the second time
unit superframe structure is aligned with a start boundary of the
second subframe of the LTE radio frame, a start boundary of each
first frame structure (NB-Slot) is aligned with a start boundary of
an odd-numbered LTE subframe, and the fourth symbol of the fourth
first frame structure (NB-Slot) is a blank symbol and is not used
for transmission. One first frame structure (NB-Slot) herein is
formed by the 2 ms subframe shown in FIG. 3.
[0217] When srs-SubframeConfig is configured as `11` on a network,
an SRS is transmitted in the third subframe of an LTE radio frame,
a start boundary of the second time unit superframe structure is
aligned with a start boundary of the second subframe of the LTE
radio frame, and a start boundary of each first frame structure
(NB-Slot) is aligned with a start boundary of an odd-numbered LTE
subframe. One first frame structure (NB-Slot) herein is formed by
the 2 ms subframe shown in FIG. 3.
[0218] When srs-SubframeConfig is configured as `6` or `12` on a
network, an SRS is transmitted in the fourth subframe and the ninth
subframe of an LTE radio frame. As shown in FIG. 14, a start
boundary of the second time unit superframe structure is aligned
with a start boundary of the first subframe of the LTE radio frame,
a start boundary of each first frame structure (NB-Slot) is aligned
with a start boundary of an even-numbered LTE subframe, and the
fourth symbol of the fifth first frame structure (NB-Slot) is a
blank symbol and is not used for transmission. One first frame
structure (NB-Slot) herein is formed by the 2 ms subframe shown in
FIG. 3.
[0219] When srs-SubframeConfig is configured as `12` on a network,
an SRS is transmitted in the fourth subframe of an LTE radio frame,
a start boundary of the second time unit superframe structure is
aligned with a start boundary of the first subframe of the LTE
radio frame, and a start boundary of each first frame structure
(NB-Slot) is aligned with a start boundary of an even-numbered LTE
subframe. One first frame structure (NB-Slot) herein is formed by
the 2 ms subframe shown in FIG. 3.
[0220] Optionally, in each first frame structure (NB-Slot), if
there is a symbol that is a blank symbol and is not used for
transmission, rate matching needs to be performed on data mapped
onto the NB-Slot, and then the data is mapped onto remaining
symbols of the NB-Slot.
[0221] Optionally, configuration information of the seven types of
second time unit superframe structures in Table 7 is indicated by
system information. The system information may be, for example,
NB-IoT system information or LTE system information. The system
information includes 3 bits, which represents eight types of
indications. As shown in the first column of Table 7, `000`
indicates an NB-IoT frame structure with an SRS configuration of
`0`, `13`, `14`, `7`, or `8`. A specific frame structure is
described in the foregoing embodiment, and details are not
described herein. By analogy, as shown in the first column of Table
7, `001` to `110` respectively indicate other NB-IoT frame
structures, and `111` is a reserved bit. In this embodiment, to
reduce a quantity of bits broadcast in the system information, LTE
SRS configurations #3 and #9 are combined. In this scenario, an
NB-IoT terminal sends an uplink 3.75 kHz subcarrier signal
according to only a situation in which a quantity of unused NB-IoT
symbols is greater. That is, as shown in the following figure, a
situation of a related configuration 3 in NB-IoT system broadcast
information may correspond to an LTE SRS configuration #3 or #9. In
this case, NB-IoT information is sent according to the LTE SRS
configuration #3. By analogy, a situation of a related
configuration 4 in NB-IoT system broadcast information may
correspond to LTE SRS configurations #4 and #10. In this case,
NB-IoT information is sent according to the LTE SRS configuration
#4. A situation of a related configuration 5 in NB-IoT system
broadcast information may correspond to LTE SRS configurations #5
and #11. In this case, NB-IoT information is sent according to the
LTE SRS configuration #5. A situation of a related configuration 6
in NB-IoT system broadcast information may correspond to LTE SRS
configurations #6 and #12. In this case, NB-IoT information is sent
according to the LTE SRS configuration #6. A situation of a related
configuration 0 in NB-IoT system broadcast information may
correspond to LTE SRS configurations #0, #13, #14, #7, and #8. In
this case, NB-IoT information is sent according to the LTE SRS
configuration #0.
[0222] Optionally, to reduce a quantity of bits broadcast in the
system information, LTE SRS configurations #0, #13, #14, #7, and #8
are combined. In this case, NB-IoT information is sent according to
the LTE SRS configuration #0. LTE SRS configurations #1, #4, #6,
#10, and #12 are combined. In this case, a start boundary of the
second time unit superframe structure is aligned with a start
boundary of the first subframe of an LTE radio frame, a start
boundary of each first frame structure (NB-Slot) is aligned with a
start boundary of an even-numbered LTE subframe, and the fourth
symbol of each of the fourth and the fifth first frame structures
(NB-Slot) is a blank symbol and is not used for transmission. One
first frame structure (NB-Slot) herein is formed by the 2 ms
subframe shown in FIG. 3. LTE SRS configurations #2, #3, #5, #9,
and #11 are combined. In this case, a start boundary of the second
time unit superframe structure is aligned with a start boundary of
the second subframe of an LTE radio frame, a start boundary of each
first frame structure (NB-Slot) is aligned with a start boundary of
an odd-numbered LTE subframe, and the fourth symbol of each of the
third and the fourth first frame structures (NB-Slot) is a blank
symbol and is not used for transmission. The foregoing combination
information may be indicated by 2 bit information in NB-IoT system
information or LTE system information.
[0223] Optionally, the NB-IoT frame structure configuration
information is indicated by system information. The system
information may be, for example, NB-IoT system information or LTE
system information. The system information includes 4 bits, which
represents 16 types of indications. The 16 types of indications
herein respectively correspond to 16 types of configurations of
srs-SubframeConfig, and corresponding NB-IoT frame structures are
described in the foregoing embodiment, and details are not
described herein.
[0224] Optionally, a demodulation reference signal in an NB-IoT
uplink subframe is transmitted on the third or the fifth symbol of
each NB-Slot.
[0225] The frame structure with a subcarrier spacing of 15 kHz in
Table 7 is similar to a legacy LTE frame structure. In this case, a
symbol length in the NB-Slot is equal to a legacy LTE symbol. A
boundary of the first NB-Slot is aligned with a boundary of the
first LTE subframe, and the same applies to subsequent NB-Slots. On
a symbol with SRS transmission configured on the network, an
NB-Slot symbol at the same moment is not used for transmission.
[0226] The foregoing describes in detail the data transmission
method and the frame structure according to the embodiments of the
present application with reference to FIG. 1 to FIG. 12, and the
following describes data transmission user equipment according to
an embodiment of the present application.
[0227] FIG. 13 is a structural block diagram of user equipment
according to an embodiment of the present application. The user
equipment 100 shown in FIG. 13 includes a processor 110 and a
transmitter 120.
[0228] The processor 110 is configured to determine a frame
structure in a time unit, where the frame structure includes N
orthogonal frequency division multiplexing OFDM symbols with a
subcarrier spacing of .DELTA.f.sub.1 and a guard period GP, a
length of the GP is greater than or equal to a time length occupied
by one OFDM symbol with a subcarrier spacing of .DELTA.f.sub.2,
.DELTA.f.sub.1 is unequal to .DELTA.f.sub.2, and N is a positive
integer.
[0229] The processor 110 is further configured to determine a
superframe structure in a second time unit, where the superframe
structure includes N first frame structures, and N is a positive
integer.
[0230] The transmitter 120 is configured to send the OFDM symbols
with a subcarrier spacing of .DELTA.f.sub.1 according to the frame
structure.
[0231] In addition, the user equipment 100 may further include a
memory 130 coupled to the processor 110, where the memory 130 may
be configured to store an instruction, and may further be
configured to store the frame structure and the like. The processor
110 may be a baseband processor, a communications processor, a
digital signal processor, an application-specific integrated
circuit, or the like. The processor 110 is configured to execute
the instruction stored in the memory 130.
[0232] It should be understood that the transmitter 120, the
processor 110, the memory 130, and the like in the user equipment
100 may be connected to each other by using a bus system 140.
[0233] It should be understood that the user equipment 100 in FIG.
13 may be configured to execute the method in the embodiments of
the present application, and the foregoing and other operations
and/or functions of all components of the user equipment are
separately for implementing corresponding processes of the methods
in FIG. 12. For brevity, details are not described herein.
[0234] A person of ordinary skill in the art may be aware that, in
combination with the examples described in the embodiments
disclosed in this specification, units and algorithm steps may be
implemented by electronic hardware or a combination of computer
software and electronic hardware. Whether the functions are
performed by hardware or software depends on particular
applications and design constraint conditions of the technical
solutions. A person skilled in the art may use different methods to
implement the described functions for each particular application,
but it should not be considered that the implementation goes beyond
the scope of the present application.
[0235] It may be clearly understood by a person skilled in the art
that, for the purpose of convenient and brief description, for a
detailed working process of the foregoing system, apparatus, and
unit, reference may be made to a corresponding process in the
foregoing method embodiments, and details are not described.
[0236] In the several embodiments provided in this application, it
should be understood that the disclosed system, apparatus, and
method may be implemented in other manners. For example, the
described apparatus embodiments are merely examples. For example,
the unit division is merely logical function division and may be
other division in actual implementation. For example, a plurality
of units or components may be combined or integrated into another
system, or some features may be ignored or not performed. In
addition, the displayed or discussed mutual couplings or direct
couplings or communication connections may be implemented by using
some interfaces. The indirect couplings or communication
connections between the apparatuses or units may be implemented in
electronic, mechanical, or other forms.
[0237] The units described as separate parts may or may not be
physically separate, and parts displayed as units may or may not be
physical units, may be located in one position, or may be
distributed on a plurality of network units. Some or all of the
units may be selected according to actual needs to achieve the
objectives of the solutions of the embodiments.
[0238] In addition, functional units in the embodiments of the
present application may be integrated into one processing unit, or
each of the units may exist alone physically, or two or more units
are integrated into one unit.
[0239] When the functions are implemented in the form of a software
functional unit and sold or used as an independent product, the
functions may be stored in a computer-readable storage medium.
Based on such an understanding, the technical solutions of the
present application essentially, or the part contributing to the
prior art, or some of the technical solutions may be implemented in
a form of a software product. The software product is stored in a
storage medium, and includes several instructions for instructing a
computer device (which may be a personal computer, a server, a
network device, or the like) to perform all or some of the steps of
the methods described in the embodiments of the present
application. The foregoing storage medium includes: any medium that
can store program code, such as a USB flash drive, a removable hard
disk, a read-only memory (Read-Only Memory, ROM), a random access
memory (Random Access Memory, RAM), a magnetic disk, or an optical
disc.
[0240] The foregoing descriptions are merely specific
implementation manners of the present application, but are not
intended to limit the protection scope of the present application.
Any variation or replacement readily figured out by a person
skilled in the art within the technical scope disclosed in the
present application shall fall within the protection scope of the
present application. Therefore, the protection scope of the present
application shall be subject to the protection scope of the
claims.
* * * * *