U.S. patent application number 15/853390 was filed with the patent office on 2019-01-03 for uplink control channel configuration for unlicensed carriers.
The applicant listed for this patent is TELEFONAKTIEBOLAGET LM ERICSSON (PUBL). Invention is credited to Fredrik Lindqvist, Yu Yang.
Application Number | 20190007937 15/853390 |
Document ID | / |
Family ID | 58800502 |
Filed Date | 2019-01-03 |
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United States Patent
Application |
20190007937 |
Kind Code |
A1 |
Yang; Yu ; et al. |
January 3, 2019 |
UPLINK CONTROL CHANNEL CONFIGURATION FOR UNLICENSED CARRIERS
Abstract
A physical uplink control channel (PUCCH) format for
transmission of uplink control information (UCI) in unlicensed
spectrum is either short PUCCH or long PUCCH. The short PUCCH
occupies less than 1 subframe in the time domain and spans an
entire system bandwidth in the frequency domain with interlacing on
a resource block level. The long PUCCH occupies one subframe in the
time domain and spans the entire system bandwidth in the frequency
domain with interlacing on a resource block level.
Inventors: |
Yang; Yu; (SOLNA, SE)
; Lindqvist; Fredrik; (JARFALLA, SE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
TELEFONAKTIEBOLAGET LM ERICSSON (PUBL) |
Stockholm |
|
SE |
|
|
Family ID: |
58800502 |
Appl. No.: |
15/853390 |
Filed: |
December 22, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15431012 |
Feb 13, 2017 |
9854569 |
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15853390 |
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PCT/IB2016/057404 |
Dec 7, 2016 |
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15431012 |
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62264091 |
Dec 7, 2015 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W 16/14 20130101;
H04L 5/0007 20130101; H04L 27/0006 20130101; H04L 5/0053 20130101;
H04W 72/0413 20130101; H04L 1/1614 20130101 |
International
Class: |
H04W 72/04 20060101
H04W072/04; H04L 27/00 20060101 H04L027/00; H04L 5/00 20060101
H04L005/00; H04W 16/14 20060101 H04W016/14 |
Claims
1. A method of operating a wireless communication device,
comprising: identifying a physical uplink control channel (PUCCH)
format for transmission of uplink control information (UCI) in
unlicensed spectrum, wherein the PUCCH format is short PUCCH or
long PUCCH, wherein the short PUCCH occupies less than 1 subframe
in the time domain and spans an entire system bandwidth in the
frequency domain with interlacing on a resource block level, and
wherein the long PUCCH occupies one subframe in the time domain and
spans the entire system bandwidth in the frequency domain with
interlacing on a resource block level; and transmitting the UCI to
a radio access node in accordance with the identified PUCCH
format.
2. The method of claim 1, wherein the UCI is transmitted to the
radio access node in coordination with one or more other wireless
communication devices.
3. The method of claim 2, wherein transmitting the UCI to the radio
access node in coordination with the one or more other wireless
communication devices comprises multiplexing the one or more other
wireless communication devices on the same interlace as the short
PUCCH or the long PUCCH.
4. The method of claim 1, wherein the PUCCH format is short PUCCH
comprising at least one demodulation reference signal (DMRS) symbol
and at least one control-data symbol in the time domain.
5. The method of claim 4, wherein the short PUCCH comprises a
sequence of symbols at the end of a downlink partial subframe.
6. The method of claim 2, wherein transmitting the UCI in
coordination with the one or more other wireless communication
devices comprises multiplexing with the one or more other wireless
communication devices using orthogonal cover codes (OCC) and cyclic
shifts (CS) on control-data symbols and reference symbols,
respectively, in the short PUCCH or long PUCCH.
7. The method of claim 4, wherein the transmitting comprises
transmitting a demodulation reference signal (DMRS) symbol on all
subcarriers within a block-interleaved frequency division multiple
access (B-IFDMA) symbol on an assigned interlace or on all assigned
interlaces across the entire system bandwidth.
8. The method of claim 4, wherein the transmitting comprises
transmitting a demodulation reference signal (DMRS) symbol once per
"n" subcarriers with a pattern that can be shifted or unshifted on
different B-IFDMA symbols, where "n" is an integer greater than
1.
9. The method of claim 2, wherein the wireless communication device
and the one or more other wireless communication devices are
assigned different interlacing patterns.
10. The method of claim 2, wherein the wireless communication
device and the one or more other wireless communication devices are
assigned the same interlacing pattern, and they apply different
orthogonal cover codes (OCC) to enable PUCCH control-data on the
same time-frequency resources.
11. A wireless communication device, comprising: at least one
processor configured to: identify a physical uplink control channel
(PUCCH) format for transmission of uplink control information (UCI)
in unlicensed spectrum, wherein the PUCCH format is short PUCCH or
long PUCCH, wherein the short PUCCH occupies less than 1 subframe
in the time domain and spans an entire system bandwidth in the
frequency domain with interlacing on a resource block level, and
wherein the long PUCCH occupies one subframe in the time domain and
spans the entire system bandwidth in the frequency domain with
interlacing on a resource block level; and at least one transmitter
configured to transmit the UCI to a radio access node in accordance
with the identified PUCCH format.
12. The wireless communication device of claim 11, wherein the UCI
is transmitted to the radio access node in coordination with one or
more other wireless communication devices.
13. The wireless communication device of claim 12, wherein
transmitting the UCI to the radio access node in coordination with
the one or more other wireless communication devices comprises
multiplexing the one or more other wireless communication devices
on the same interlace as the short PUCCH or the long PUCCH.
14. The wireless communication device of claim 11, wherein the
PUCCH format is short PUCCH comprising at least one demodulation
reference signal (DMRS) symbol and at least one control-data symbol
in the time domain.
15. The wireless communication device of claim 14, wherein the
short PUCCH comprises a sequence of symbols at the end of a
downlink partial subframe.
16. The wireless communication device of claim 12, wherein
transmitting the UCI in coordination with the one or more other
wireless communication devices comprises multiplexing with the one
or more other wireless communication devices using orthogonal cover
codes (OCC) and cyclic shifts (CS) on data symbols and reference
symbols, respectively, in the short PUCCH or long PUCCH.
17. The wireless communication device of claim 14, wherein the
transmitting comprises transmitting a demodulation reference signal
(DMRS) symbol on all subcarriers within a block-interleaved
frequency division multiple access (B-IFDMA) symbol on an assigned
interlace or on all assigned interlaces across the entire system
bandwidth.
18. The wireless communication device of claim 14, wherein the
transmitting comprises transmitting a demodulation reference signal
(DMRS) symbol once per "n" subcarriers with a pattern that can be
shifted or unshifted on different B-IFDMA symbols, where "n" is an
integer greater than 1.
19. The wireless communication device of claim 12, wherein the
wireless communication device and the one or more other wireless
communication devices are assigned different interlacing
patterns.
20. The wireless communication device of claim 12, wherein the
wireless communication device and the one or more other wireless
communication devices are assigned the same interlacing pattern,
and they apply different orthogonal cover codes (OCC) to enable
PUCCH control-data on the same time-frequency resources.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 15/431,012, filed Feb. 13, 2017, now patented under U.S. Pat.
No. 9,854,569 on Dec. 26, 2017, which is a continuation of
International Application No. PCT/IB2016/057404, filed Dec. 7,
2016, which designates the United States, and which claims priority
to U.S. Provisional Application No. 62/264,091, filed on Dec. 7,
2015, the disclosure disclosures of which is are hereby
incorporated by reference in its their entirety.ch is hereby
incorporated by reference in its entirety.
TECHNICAL FIELD
[0002] The disclosed subject matter relates generally to
telecommunications. Certain embodiments relate more particularly to
uplink control channel configuration for unlicensed carriers.
BACKGROUND
[0003] The standalone Long-Term Evolution (LTE) in unlicensed
spectrum (LTE-U) forum and 3.sup.rd Generation Partnership Project
(3GPP) Release 14 (Rel-14) work item on Uplink Licensed-Assisted
Access (LAA) intends to allow LTE User Equipments (UEs) to transmit
on the uplink in the unlicensed 5 GHz or license-shared 3.5 GHz
radio spectrum. For standalone LTE-U, initial random access and
subsequent UL transmissions take place entirely on unlicensed
spectrum. Regulatory requirements may prohibit transmissions in the
unlicensed spectrum without prior channel sensing.
[0004] Because the unlicensed spectrum is typically shared with
other radios of similar or dissimilar wireless technologies, a
so-called listen-before-talk (LBT) method may be applied. LBT
involves sensing the medium for a pre-defined minimum amount of
time and backing off if the channel is busy.
[0005] Today, unlicensed 5 GHz spectrum is mainly used by equipment
implementing the IEEE 802.11 Wireless Local Area Network (WLAN)
standard, also known as Wi-Fi.
[0006] LTE uses Orthogonal Frequency Division Multiplexing (OFDM)
in the downlink and Discrete Fourier Transform spread (DFT-spread)
OFDM (also referred to as single-carrier FDMA [SC-FDMA]) in the
uplink. The basic LTE downlink physical resource can thus be seen
as a time-frequency grid as illustrated in Figure (FIG. 1, where
each resource element corresponds to one OFDM subcarrier during one
OFDM symbol interval. The uplink subframe has the same subcarrier
spacing (15 kHz) as the downlink and the same number of SC-FDMA
symbols in the time domain as OFDM symbols in the downlink.
[0007] In the time domain, LTE downlink transmissions are organized
into radio frames of 10 ms, each radio frame comprising ten
equally-sized subframes of length T.sub.subframe=1 ms as shown in
FIG. 2. Each subframe comprises two slots of duration 0.5 ms each,
and the slot numbering within a frame ranges from 0 to 19. For
normal cyclic prefix, one subframe comprises 14 OFDM symbols. The
duration of each symbol is approximately 71.4 .mu.s when including
the cyclic prefix.
[0008] Furthermore, the resource allocation in LTE is typically
described in terms of resource blocks, where a resource block
corresponds to 12 contiguous subcarriers in the frequency domain.
Resource blocks are numbered in the frequency domain, starting from
0 at one end of the system bandwidth.
[0009] Up to now, the spectrum used by LTE is dedicated to LTE.
This has the benefit of allowing LTE to avoid complications from
sharing the spectrum and to achieve commensurate gains in spectrum
efficiency. However, the spectrum allocated to LTE is limited and
cannot meet the ever increasing demand for larger throughput from
applications/services. Consequently, a new study item has been
initiated in 3GPP on extending LTE to exploit unlicensed spectrum
in addition to licensed spectrum.
[0010] Unlicensed spectrum can, by definition, be simultaneously
used/shared by multiple different technologies. Therefore, LTE
should consider coexistence with other systems such as IEEE 802.11
(Wi-Fi). Operating LTE in the same manner in unlicensed spectrum as
in licensed spectrum can seriously degrade the performance of Wi-Fi
as Wi-Fi will not transmit once it detects the channel is
occupied.
[0011] Furthermore, one way to utilize unlicensed spectrum reliably
is to transmit essential control signals and channels on a licensed
carrier. For example, as shown in FIG. 3, a UE is connected to a
PCell in the licensed band and one or more SCells in the unlicensed
band. In this description, a secondary cell in unlicensed spectrum
is referred to as a licensed-assisted access secondary cell (LAA
SCell).
[0012] A new industry forum has been initiated on extending LTE to
operate entirely on unlicensed spectrum in a standalone mode, which
is referred to as "MuLTEfire". In MuLTEfire there is no licensed
carrier for essential control signals transmissions and control
channels. Accordingly, all transmission occurs on unlicensed
spectrum with no guaranteed channel access availability, yet it
must also fulfill the regulatory requirements on the unlicensed
spectrum.
SUMMARY
[0013] In some embodiments of the disclosed subject matter, a
method of operating a wireless communication device comprises
identifying a physical uplink control channel (PUCCH) format for
transmission of uplink control information (UCI) in unlicensed
spectrum, wherein the PUCCH format is short PUCCH or long PUCCH,
wherein the short PUCCH occupies less than 1 subframe in the time
domain and spans an entire system bandwidth in the frequency domain
with interlacing on a resource block level, and wherein the long
PUCCH occupies one subframe in the time domain and spans the entire
system bandwidth in the frequency domain with interlacing on a
resource block level, and transmitting the UCI to a radio access
node in accordance with the identified PUCCH format.
[0014] In certain related embodiments, the UCI is transmitted to
the radio access node in coordination with one or more other
wireless communication devices. In some such embodiments,
transmitting the UCI to the radio access node in coordination with
the one or more other wireless communication devices comprises
multiplexing the one or more other wireless communication devices
on the same interlace as the short PUCCH or the long PUCCH. In some
such embodiments, transmitting the UCI in coordination with the one
or more other wireless communication devices comprises multiplexing
with the one or more other wireless communication devices using
orthogonal cover codes (OCC) and cyclic shifts (CS) on control-data
symbols and reference symbols, respectively, in the short PUCCH or
long PUCCH.
[0015] In certain related embodiments, the PUCCH format is short
PUCCH.
[0016] In certain related embodiments, the PUCCH format is long
PUCCH. In some such embodiments, the short PUCCH comprises at least
one demodulation reference signal (DMRS) symbol and at least one
control-data symbol in the time domain. In some such embodiments,
the short PUCCH comprises a sequence of symbols at the end of a
downlink partial subframe.
[0017] In certain related embodiments, the transmitting comprises
transmitting a demodulation reference signal (DMRS) symbol on all
subcarriers within a block-interleaved frequency division multiple
access (B-IFDMA) symbol on an assigned interlace or on all assigned
interlaces across the entire system bandwidth.
[0018] In certain related embodiments, the transmitting comprises
transmitting a demodulation reference signal (DMRS) symbol once per
"n" subcarriers with a pattern that can be shifted or unshifted on
different B-IFDMA symbols, where "n" is an integer greater than
1.
[0019] In certain related embodiments, the wireless communication
device and the one or more other wireless communication devices are
assigned different interlacing patterns.
[0020] In certain related embodiments, the wireless communication
device and the one or more other wireless communication devices are
assigned the same interlacing pattern, and they apply different
orthogonal cover codes (OCC) to enable PUCCH control-data on the
same time-frequency resources.
[0021] In some embodiments of the disclosed subject matter, a
wireless communication device comprises at least one processor
configured to identify a physical uplink control channel (PUCCH)
format for transmission of uplink control information (UCI) in
unlicensed spectrum, wherein the PUCCH format is short PUCCH or
long PUCCH, wherein the short PUCCH occupies less than 1 subframe
in the time domain and spans an entire system bandwidth in the
frequency domain with interlacing on a resource block level, and
wherein the long PUCCH occupies one subframe in the time domain and
spans the entire system bandwidth in the frequency domain with
interlacing on a resource block level, and at least one transmitter
configured to transmit the UCI to a radio access node in accordance
with the identified PUCCH format.
[0022] In certain related embodiments, the UCI is transmitted to
the radio access node in coordination with one or more other
wireless communication devices.
[0023] In certain related embodiments, transmitting the UCI to the
radio access node in coordination with the one or more other
wireless communication devices comprises multiplexing the one or
more other wireless communication devices on the same interlace as
the short PUCCH or the long PUCCH.
[0024] In certain related embodiments, the PUCCH format is short
PUCCH.
[0025] In certain related embodiments, the PUCCH format is long
PUCCH.
[0026] In certain related embodiments, the short PUCCH comprises at
least one demodulation reference signal (DMRS) symbol and at least
one control-data symbol in the time domain.
[0027] In certain related embodiments, the short PUCCH comprises a
sequence of symbols at the end of a downlink partial subframe.
[0028] In certain related embodiments, transmitting the UCI in
coordination with the one or more other wireless communication
devices comprises multiplexing with the one or more other wireless
communication devices using orthogonal cover codes (OCC) and cyclic
shifts (CS) on data symbols and reference symbols, respectively, in
the short PUCCH or long PUCCH.
[0029] In certain related embodiments, the transmitting comprises
transmitting a demodulation reference signal (DMRS) symbol on all
subcarriers within a block-interleaved frequency division multiple
access (B-IFDMA) symbol on an assigned interlace or on all assigned
interlaces across the entire system bandwidth.
[0030] In certain related embodiments, the transmitting comprises
transmitting a demodulation reference signal (DMRS) symbol once per
"n" subcarriers with a pattern that can be shifted or unshifted on
different B-IFDMA symbols, where "n" is an integer greater than
1.
[0031] In certain related embodiments, the wireless communication
device and the one or more other wireless communication devices are
assigned different interlacing patterns.
[0032] In certain related embodiments, the wireless communication
device and the one or more other wireless communication devices are
assigned the same interlacing pattern, and they apply different
orthogonal cover codes (OCC) to enable PUCCH control-data on the
same time-frequency resources.
[0033] In some embodiments of the disclosed subject matter, a
method of operating a radio access node comprises identifying a
physical uplink control channel (PUCCH) format to be used by at
least one wireless communication device for transmission of uplink
control information (UCI) in unlicensed spectrum, wherein the PUCCH
format is short PUCCH or long PUCCH, wherein the short PUCCH
occupies less than 1 subframe in the time domain and spans an
entire system bandwidth in the frequency domain with interlacing on
a resource block level, and wherein the long PUCCH occupies one
subframe in the time domain and spans the entire system bandwidth
in the frequency domain with interlacing on a resource block level,
and receiving the UCI from the at least one wireless communication
device in accordance with the identified PUCCH format.
[0034] In certain related embodiments, identifying the PUCCH format
comprises selecting between short PUCCH and long PUCCH according to
at least one of an eNodeB timing configuration and a hybrid
automatic repeat request (HARM) protocol.
[0035] In certain related embodiments, the received UCI is
multiplexed on the same interlace as the short PUCCH or the long
PUCCH with information transmitted from at least one other wireless
communication device.
[0036] In certain related embodiments, the PUCCH format is short
PUCCH.
[0037] In certain related embodiments, the PUCCH format is long
PUCCH.
[0038] In certain related embodiments, the short PUCCH comprises at
least one demodulation reference signal (DMRS) symbol and at least
one control-data symbol in the time domain.
[0039] In certain related embodiments, the short PUCCH comprises a
sequence of symbols at the end of a downlink partial subframe.
[0040] In certain related embodiments, the received UCI is
multiplexed in the short PUCCH or long PUCCH with information
transmitted from at least one other wireless communication
device.
[0041] In certain related embodiments, the UCI and the information
transmitted from the at least one other wireless communication
device are multiplexed using orthogonal cover codes (OCC) and
cyclic shifts (CS) on control-data symbols and reference symbols,
respectively.
[0042] In certain related embodiments, the PUCCH format comprises a
demodulation reference signal (DMRS) symbol on all subcarriers
within a block-interleaved frequency division multiple access
(B-IFDMA) symbol on an assigned interlace or on all assigned
interlaces across the entire system bandwidth.
[0043] In certain related embodiments, the PUCCH format comprises a
demodulation reference signal (DMRS) symbol once per "n"
subcarriers with a pattern that can be shifted or unshifted on
different B-IFDMA symbols, where "n" is an integer greater than
1.
[0044] In certain related embodiments, the UCI is multiplexed with
UCI from at least one other wireless communication device using
different interlacing patterns within the same subframe.
[0045] In certain related embodiments, the UCI is multiplexed with
UCI from at least one other wireless communication device using the
same interlacing pattern within the same subframe.
[0046] In certain related embodiments, the UCI from the at least
one wireless communication device and the at least one other
wireless communication device are subject to different orthogonal
cover codes (OCC).
[0047] In some embodiments of the disclosed subject matter, a radio
access node comprises at least one processor and memory
collectively configured to identify a physical uplink control
channel (PUCCH) format to be used by at least one wireless
communication device for transmission of uplink control information
(UCI) in unlicensed spectrum, wherein the PUCCH format is short
PUCCH or long PUCCH, wherein the short PUCCH occupies less than 1
subframe in the time domain and spans an entire system bandwidth in
the frequency domain with interlacing on a resource block level,
and wherein the long PUCCH occupies one subframe in the time domain
and spans the entire system bandwidth in the frequency domain with
interlacing on a resource block level, and a receiver configured to
receive the UCI from the at least one wireless communication device
in accordance with the identified PUCCH format.
[0048] In certain related embodiments, identifying the PUCCH format
comprises selecting between short PUCCH and long PUCCH according to
at least one of an eNodeB timing configuration and a hybrid
automatic repeat request (HARM) protocol.
[0049] In certain related embodiments, the received UCI is
multiplexed on the same interlace as the short PUCCH or the long
PUCCH with information transmitted from at least one other wireless
communication device.
[0050] In certain related embodiments, the PUCCH format is short
PUCCH.
[0051] In certain related embodiments, the PUCCH format is long
PUCCH.
[0052] In certain related embodiments, the short PUCCH comprises at
least one demodulation reference signal (DMRS) symbol and at least
one control-data symbol in the time domain.
[0053] In certain related embodiments, the short PUCCH comprises a
sequence of symbols at the end of a downlink partial subframe.
[0054] In certain related embodiments, the received UCI is
multiplexed in the short PUCCH or long PUCCH with information
transmitted from at least one other wireless communication
device.
[0055] In certain related embodiments, the UCI and the information
transmitted from the at least one other wireless communication
device are multiplexed using orthogonal cover codes (OCC) and
cyclic shifts (CS) on control-data symbols and reference symbols,
respectively.
[0056] In certain related embodiments, the PUCCH format comprises a
demodulation reference signal (DMRS) symbol on all subcarriers
within a block-interleaved frequency division multiple access
(B-IFDMA) symbol on an assigned interlace or on all assigned
interlaces across the entire system bandwidth.
[0057] In certain related embodiments, the PUCCH format comprises a
demodulation reference signal (DMRS) symbol once per "n"
subcarriers with a pattern that can be shifted or unshifted on
different B-IFDMA symbols, where "n" is an integer greater than
1.
[0058] In certain related embodiments, the UCI is multiplexed with
UCI from at least one other wireless communication device using
different interlacing patterns within the same subframe.
[0059] In certain related embodiments, the UCI is multiplexed with
UCI from at least one other wireless communication device using the
same interlacing pattern within the same subframe.
[0060] In certain related embodiments, the UCI from the at least
one wireless communication device and the at least one other
wireless communication device are subject to different orthogonal
cover codes (OCC).
[0061] In some embodiments of the disclosed subject matter, a
wireless communication device comprises an identification module
configured to identify a physical uplink control channel (PUCCH)
format for transmission of uplink control information (UCI) in
unlicensed spectrum, wherein the PUCCH format is short PUCCH or
long PUCCH, wherein the short PUCCH occupies less than 1 subframe
in the time domain and spans an entire system bandwidth in the
frequency domain with interlacing on a resource block level, and
wherein the long PUCCH occupies one subframe in the time domain and
spans the entire system bandwidth in the frequency domain with
interlacing on a resource block level, and a transmission module
configured to transmit the UCI to a radio access node in accordance
with the identified PUCCH format.
[0062] In some embodiments of the disclosed subject matter a radio
access node comprises an identification module configured to
identify a physical uplink control channel (PUCCH) format to be
used by at least one wireless communication device for transmission
of uplink control information (UCI) in unlicensed spectrum, wherein
the PUCCH format is short PUCCH or long PUCCH, wherein the short
PUCCH occupies less than 1 subframe in the time domain and spans an
entire system bandwidth in the frequency domain with interlacing on
a resource block level, and wherein the long PUCCH occupies one
subframe in the time domain and spans the entire system bandwidth
in the frequency domain with interlacing on a resource block level,
and a reception module configured to receive the UCI from the at
least one wireless communication device in accordance with the
identified PUCCH format.
BRIEF DESCRIPTION OF THE DRAWINGS
[0063] The drawings illustrate selected embodiments of the
disclosed subject matter. In the drawings, like reference labels
denote like features.
[0064] FIG. 1 shows an example LTE downlink physical resource.
[0065] FIG. 2 shows an example LTE time-domain structure.
[0066] FIG. 3 shows an example of LAA to unlicensed spectrum using
LTE carrier aggregation.
[0067] FIG. 4 shows an example of short PUCCH occupying two symbols
and one interlace.
[0068] FIG. 5 shows an example of short PUCCH multiplexing with
PUSCH transmission in the same subframe.
[0069] FIG. 6 shows an example of two PUCCH UEs DS multiplexing on
the same interlace(s) with N.sub.PRB PRBs.
[0070] FIG. 7 shows an example of a long PUCCH.
[0071] FIG. 8 shows an example of long PUCCH multiplexing with
PUSCH transmission in the same subframe
[0072] FIG. 9 shows an example of long PUCCH multiplexing with
PUSCH transmission in the same subframe with symbol-based frequency
hopping.
[0073] FIG. 10 shows an example of two PUCCH UEs RS multiplexing on
the same interlace(s).
[0074] FIG. 11 shows an example of an LTE network.
[0075] FIG. 12 shows an example of a wireless communication
device.
[0076] FIG. 13 shows an example of a radio access node.
[0077] FIG. 14 shows an example method of operating a wireless
communication device.
[0078] FIG. 15 shows an example of a wireless communication
device.
[0079] FIG. 16 shows an example method of operating a radio access
node.
[0080] FIG. 17 shows an example of a radio access node.
[0081] FIG. 18 shows an example of B-IFDMA.
[0082] FIG. 19 shows an example of inter- and intra-symbol OCC.
DETAILED DESCRIPTION
[0083] The following description presents various embodiments of
the disclosed subject matter. These embodiments are presented as
teaching examples and are not to be construed as limiting the scope
of the disclosed subject matter. For example, certain details of
the described embodiments may be modified, omitted, or expanded
upon without departing from the scope of the disclosed subject
matter.
[0084] In LAA/standalone LTE-U, uplink control information (UCI)
such as HARQ-ACK, CSI are sent from UE to eNB on the control
channel PUCCH when there is no UL-SCH data scheduled. The PUCCH
design up to Rel-13 is only for carriers in licensed spectrum,
which is not possible to be reused for carriers in unlicensed
spectrum due to regulatory requirements. In addition, because there
is no longer any guaranteed channel access availability for PUCCH,
special consideration should be given when designing the PUCCH on
carriers in unlicensed spectrum.
[0085] Certain embodiments of the disclosed subject matter provide
a physical layer design of uplink control channel (e.g., PUCCH)
format for LAA/standalone LTE-U. Various alternative embodiments
may employ either or both of two PUCCH formats, including a short
PUCCH and a long PUCCH. The two different PUCCH formats can be
considered for UCI transmission depending on e.g. eNB timing
configuration and/or HARQ protocol. Although several of the
described embodiments relate to PUCCH, the described concepts could
nevertheless be applied to other types of uplink control
channels.
[0086] The short PUCCH typically occupies less than one subframe
(e.g. 1-4 SC-FDMA/OFDM symbols) in the time domain, while the long
PUCCH typically occupies 1 subframe. Both formats span the entire
bandwidth with interlacing. UE multiplexing is supported on both
formats using Orthogonal Cover Codes (OCC) and Cyclic Shifts (CS)
on data symbols and reference symbols. The normal PUCCH can also be
multiplexed with PUSCH transmission from same or different UEs.
[0087] In certain embodiments, the establishment and/or use of a
particular PUCCH format may be coordinated by one or more radio
access nodes. Such coordination may include, for instance,
determining the format and signaling scheduling and/or format
information from the one or more radio access nodes to one or more
wireless communication devices. The determining of the format may
include e.g. selecting a PUCCH format according to an eNB timing
configuration or a HARQ protocol. The signaling may take the form
of e.g. downlink control signaling or radio resource control (RRC)
configuration signaling.
[0088] The described embodiments may provide various potential
benefits compared to conventional approaches. Some embodiments may,
for instance, allow UCI to be transmitted on PUCCH on carriers in
unlicensed spectrum; some embodiments may allow similar
functionality as legacy LTE PUCCH to be maintained; and some
embodiments may allow UE multiplexing to be supported on new PUCCH
formats.
[0089] The following embodiments include physical layer
configuration of PUCCH in unlicensed spectrum. Certain methods or
concepts described below may be used for both single- and
multi-carrier transmissions. The proposed approaches may also apply
to different variations of LTE operating in unlicensed spectrum,
such as LAA, LTE-U and standalone LTE-U.
[0090] In the following description, the term "short PUCCH" refers
to a PUCCH that is relatively short in the time domain, e.g., less
than 1 subframe. For example, a short PUCCH may occupy 1-4 SC-FDMA
or OFDM symbols depending on eNB configuration. In the frequency
domain, a short PUCCH may span the whole bandwidth by interlacing.
Similarly, the term "long PUCCH" refers to a PUCCH that is
relatively long in the time domain, e.g., 1 subframe. In the
frequency domain, a long PUCCH may span the whole bandwidth by
interlacing.
[0091] A short PUCCH or long PUCCH is considered to span the whole
bandwidth by interlacing if the interlaces of the short PUCCH or
long PUCCH are included in an interlacing pattern that spans the
entire bandwidth, as illustrated e.g. in FIG. 7. Terms such as
"whole bandwidth", "entire bandwidth", "entire system bandwidth",
and so on, generally refer to the transmission bandwidth of a
carrier. For instance, such terms may refer to the transmission
bandwidth of a 10 MHz or 20 MHz carrier, which may be slightly less
than 10 MHz or 20 MHz, respectively.
[0092] The term "interlacing" refers to a technique in which
physical resources are assigned or allocated according to a pattern
such as one of those illustrated in FIGS. 4-5 and 7-10, for
instance. The term "interlace" refers to a set of physical
resources that forms part of an interlacing pattern, with an
example interlace being two symbols of a resource block as shown in
FIG. 4 or two resource blocks as shown in FIG. 7. In general,
interlacing is considered to be performed at a resource block level
if an interlace spans a set of subcarriers that corresponds to the
size of a resource block in the frequency domain. For instance,
FIGS. 4 and 7 both show examples of interlacing at a resource block
level. In contrast, interlacing is considered to be performed at a
subcarrier level if an interlace only spans a subcarrier in the
frequency domain. In the context of LTE and related systems,
interlacing at a resource block level can also be referred to as
block-interleaved frequency division multiple access (B-IFDMA),
with which an inverse Fourier transform (IFFT) of the illustrated
PUCCH physical resources with zero values in between, create a time
domain waveform being referred to as a B-IFDMA symbol. The size of
the mentioned IFFT (in the transmitter) typically corresponds to
the system bandwidth. An example of B-IFDMA is shown in FIG. 18,
which is a simplified block diagram of an B-IFDMA transmitter for
short/long PUCCH, where for example M=120 and N=2048 with a 20 MHz
system bandwidth when using 1 interlace of 10 RBs. In the example
of FIG. 18, a third interlace is assigned out of 10 possible.
[0093] FIG. 4 shows an example of short PUCCH occupying two symbols
in the time domain and one interlace in the frequency domain. In
one example, demodulation reference signal (DMRS) is sent on all
subcarriers within a B-IFDMA symbol on the assigned interlace(s) or
on all interlaces across the whole bandwidth, e.g. across the whole
maximum transmission bandwidth or system bandwidth. In another
example, DMRS is sent on every few number of subcarriers, e.g., 6
subcarriers (e.g. to enable more PUCCH data) whose pattern can be
shifted or unshifted on different B-IFDMA symbols, as illustrated
in the right-most part of FIG. 4.
[0094] Multiple PUCCH UEs can be multiplexed on a PUCCH resource by
various alternative approaches as explained below. PUCCH UEs can
also be multiplexed with PUSCH UEs in the same subframe in a way
that PUSCH transmission for other UEs occupying other interlacing
patterns as shown in FIG. 5.
[0095] For PUCCH multiplexing, in one example PUCCH UEs are
assigned different interlacing patterns, i.e., frequency division
multiplexing.
[0096] In another example, multiple PUCCH UEs are assigned the same
interlacing pattern, in which case UEs apply different Orthogonal
Cover Codes (OCC) to enable multiplexing of PUCCH data on the same
time-frequency resources. In this context, the OCCs can be employed
in two different ways, or in a combination of both, i.e., via
inter-symbol OCC or and/or via intra-symbol OCC. FIG. 19 shows
examples of inter-DS OCC length-2 (top of FIG. 19) and intra-DS OCC
length-2 (bottom of FIG. 19) with bipolar Hadamard OCC.
[0097] FIG. 6 shows an example of two PUCCH UEs DS multiplexing on
the same interlace(s) with N.sub.PRB PRBs. In this example, with
OFDM modulation, OCC spreading is applied within a symbol in the
frequency domain for the total number of allocated subcarriers
(SC). In case of B-IFDMA modulation, the OCC spreading within a
symbol is similar to FIG. 6 but instead typically applied per
physical resource block (PRB) and furthermore before the
transmitter DFT. This latter case of intra-symbol OCC corresponds
to OCC on a per PRB-basis by essentially assuming N.sub.PRB=1 in
FIG. 6 for each PRB within the allocated interlace(s).
[0098] It should be emphasized that FIG. 6 exemplifies the case
where 2 UEs are multiplexed. For B-IFDMA and intra-symbol OCC on a
PRB-basis, the 2 UE multiplexing case corresponds to that each UE
applies an OCC-length of 2 (i.e., 2 repeated symbols). An extension
to multiplexing e.g. 4 or 6 UEs with B-IFDMA using intra-symbol OCC
on a PRB-basis follows directly by instead applying an OCC of
length-4 or length-6 (i.e., repeating 4 or 6 subcarriers within
each PRB). The OCC sequences can for example be based on a Hadamard
matrix with +1, -1 as in FIG. 6 or based on the columns/rows of an
orthogonal matrix such as the DFT matrix. The latter may be
preferred with e.g. 4 or 6 intra-symbol OCC multiplexed UEs. As
another example, OCC spreading is applied between B-IFDMA symbols
which contain data symbols (DS). In the latter case, the OCC can be
applied after the transmitter modulation, i.e., in the time domain.
Equivalently, the inter-symbol OCC can be applied in the frequency
domain or before the transmitter DFT, since it corresponds to
scalar multiplication. The reference symbols (RS or so called DMRS)
are using existing DMRS sequences in LTE uplink based on Zadoff-Chu
sequence (assuming >2 PRBs, for fewer PRBs other sequences are
used). Multiple UEs are typically using the same root sequence and
transmit RS on the same time-frequency resources. For RS
multiplexing, different cyclic shifts are applied for different
UEs.
[0099] The HARQ feedback and the corresponding process IDs could
either be listed explicitly or e.g. be provided as a bitmap (one or
two bits per process). To align the design with 3GPP Rel-13 CA, the
UCI on short PUCCH (sPUCCH) is attached with an 8-bit CRC and
encoded using Tail Biting Convolutional Code (TBCC) for medium to
large payload size, e.g., >16-20 bits payload. For shorter
payloads, e.g. <16-20 bits, a block code may be used without CRC
to improve the performance, for instance, a Reed-Muller code as
utilized by LTE. Other encoding types could also be used. The
encoded symbols are mapped to available resource elements (Res),
e.g., in a frequency first time second manner. Similar features may
also be used in relation to long PUCCH.
[0100] FIG. 7 shows an example of a long PUCCH, where the PUCCH
occupies one interlace in one subframe with two DMRS symbols per
subframe. Other number of DMRS per subframe could also be used,
e.g. 4 symbols per subframe as in LTE PUCCH format 3. In general,
long PUCCH occupies 1 subframe in the time domain, and it spans the
whole bandwidth by interlacing in the frequency domain.
Demodulation reference signal (DMRS) is sent on all subcarriers
within a B-IFDMA symbol on the assigned interlace(s) or on all
interlaces across the whole bandwidth.
[0101] Similar to short PUCCH, multiple PUCCH UEs can also be
multiplexed using long PUCCH. PUCCH UEs can also be multiplexed
with PUSCH UEs in the same subframe using different interlacing
patterns for PUCCH data and PUSCH data transmissions as shown in
FIG. 8 without frequency hopping. In another example, frequency
hopping is enabled and UEs are multiplexed by using the hopped
resources. One example is to have symbol-based frequency hopping as
shown in FIG. 9 (where the interlace numbering refers to the
location used at the first symbol in the subframe).
[0102] For PUCCH multiplexing, in one example, PUCCH UEs are
assigned different interlacing patterns compared to PUSCH UEs and
other PUCCH UEs.
[0103] In another example, multiple PUCCH UEs are assigned the same
interlacing pattern. For data symbols (DS), UEs apply different
Orthogonal Cover Codes (OCC) to be multiplexed on the same
time-frequency resources. As one example, OCC spreading is applied
within a B-IFDMA symbol before the transmitter DFT/IFFT for the
total number of allocated subcarriers as shown in FIG. 6, or per
PRB-basis by essentially assuming N.sub.PRB=1 for each PRB within
the allocated interlace(s), as previously explained In case there
is a B-IFDMA, OCC is applied before DFT. As another example, OCC
spreading is applied between B-IFDMA symbols which contain DS.
[0104] The reference symbols (RS or so called DMRS) use existing
DMRS sequences in LTE uplink based on Zadoff-Chu sequence (assuming
>2 PRBs). Multiple UEs use the same root sequence and transmit
RS on the same time-frequency resources. For RS multiplexing, in
one example, the multiple PUCCH and PUSCH UEs apply different
cyclic shifts within one RS symbol.
[0105] In another example, two UEs are multiplexed using OCC [1 1]
and [1 -1] on the two DMRS symbols. In a further example, multiple
UEs apply both OCC between DMRS symbols and cyclic shifts within
one DMRS symbol as shown in FIG. 10. More specifically, the PUSCH
UEs can apply OCC [1 1] for the DMRSs while the PUCCH UEs apply OCC
[1 -1]. In this way, the total number of DMRS CS (i.e., resources)
can be split among all PUCCH UEs independently of the number of
PUSCH UEs, and vice versa.
[0106] The described embodiments may be implemented in any
appropriate type of communication system supporting any suitable
communication standards and using any suitable components. As one
example, certain embodiments may be implemented in an LTE network,
such as that illustrated in FIG. 11.
[0107] Referring to FIG. 11, a communication network 1100 comprises
a plurality of wireless communication devices 1105 (e.g.,
conventional UEs, machine type communication
[MTC]/machine-to-machine [M2M] UEs) and a plurality of radio access
nodes 1110 (e.g., eNodeBs or other base stations). Communication
network 1100 is organized into cells 1115, which are connected to a
core network 120 via corresponding to radio access nodes 1110.
Radio access nodes 1110 are capable of communicating with wireless
communication devices 1105 along with any additional elements
suitable to support communication between wireless communication
devices or between a wireless communication device and another
communication device (such as a landline telephone).
[0108] Although wireless communication devices 1105 may represent
communication devices that include any suitable combination of
hardware and/or software, these wireless communication devices may,
in certain embodiments, represent devices such as an example
wireless communication device illustrated in greater detail by FIG.
12. Similarly, although the illustrated radio access node may
represent network nodes that include any suitable combination of
hardware and/or software, these nodes may, in particular
embodiments, represent devices such as the example radio access
node illustrated in greater detail by FIG. 13.
[0109] Referring to FIG. 12, a wireless communication device 1200
comprises a processor 1205, a memory, a transceiver 1215, and an
antenna 1220. In certain embodiments, some or all of the
functionality described as being provided by UEs, MTC or M2M
devices, and/or any other types of wireless communication devices
may be provided by the device processor executing instructions
stored on a computer-readable medium, such as the memory shown in
FIG. 12. Alternative embodiments may include additional components
beyond those shown in FIG. 12 that may be responsible for providing
certain aspects of the device's functionality, including any of the
functionality described herein.
[0110] Referring to FIG. 13, a radio access node 1300 comprises a
node processor 1305, a memory 1310, a network interface 1315, a
transceiver 1320, and an antenna 1325. In certain embodiments, some
or all of the functionality described as being provided by a base
station, a node B, an enodeB, and/or any other type of network node
may be provided by node processor 1305 executing instructions
stored on a computer-readable medium, such as memory 1310 shown in
FIG. 13. Alternative embodiments of radio access node 1300 may
comprise additional components to provide additional functionality,
such as the functionality described herein and/or related
supporting functionality.
[0111] FIGS. 14-16 illustrate various methods and apparatuses in
which some or all of the above features may potentially be
implemented.
[0112] FIG. 14 is a flowchart illustrating a method 1400 of
operating a wireless communication device. The method of FIG. 14
could be performed by a wireless communication device as
illustrated in any of FIG. 11, 12 or 15, for instance.
[0113] Referring to FIG. 14, method 1400 comprises identifying a
physical uplink control channel (PUCCH) format for transmission of
uplink control information (UCI) in unlicensed spectrum, wherein
the PUCCH format is short PUCCH or long PUCCH, wherein the short
PUCCH occupies less than 1 subframe in the time domain and spans an
entire system bandwidth in the frequency domain with interlacing on
a resource block level, and wherein the long PUCCH occupies one
subframe in the time domain and spans the entire system bandwidth
in the frequency domain with interlacing on a resource block level
(S1405), and transmitting the UCI to a radio access node in
accordance with the identified PUCCH format (S1410). In this and
other embodiments, "identifying" or "determining" a PUCCH format
may be performed in various alternative ways, such as determining
the format based on information available to the wireless
communication device, reading an indication of the format from a
memory in the wireless communication device, being preconfigured to
use the format, receiving signaling from a radio access node that
identifies the format, and so on.
[0114] In certain embodiments, the UCI is transmitted to the radio
access node in coordination with one or more other wireless
communication devices. In certain related embodiments, transmitting
the UCI in coordination with the one or more other wireless
communication devices comprises multiplexing with the one or more
other wireless communication devices using orthogonal cover codes
(OCC) and cyclic shifts (CS) on control-data symbols and reference
symbols, respectively, in the short PUCCH or long PUCCH. In certain
other related embodiments, transmitting the UCI to the radio access
node in coordination with the one or more other wireless
communication devices comprises multiplexing the one or more other
wireless communication devices on the same interlace as the short
PUCCH or the long PUCCH. In certain other related embodiments, the
wireless communication device and the one or more other wireless
communication devices are assigned different interlacing patterns.
In certain other related embodiments, the wireless communication
device and the one or more other wireless communication devices are
assigned the same interlacing pattern, and they apply different
orthogonal cover codes (OCC) to enable PUCCH control-data on the
same time-frequency resources.
[0115] In certain embodiments, the PUCCH format is short PUCCH and
the short PUCCH comprises at least one demodulation reference
signal (DMRS) symbol and at least one control-data symbol in the
time domain. In certain related embodiments, the short PUCCH
comprises a sequence of symbols at the end of a downlink partial
subframe.
[0116] In certain embodiments, the PUCCH format is short PUCCH and
the transmitting comprises transmitting a demodulation reference
signal (DMRS) symbol on all subcarriers within a block-interleaved
frequency division multiple access (B-IFDMA) symbol on an assigned
interlace or on all assigned interlaces across the entire system
bandwidth.
[0117] In certain embodiments, the PUCCH format is short PUCCH and
the transmitting comprises transmitting a demodulation reference
signal (DMRS) symbol once per "n" subcarriers with a pattern that
can be shifted or unshifted on different B-IFDMA symbols, where "n"
is an integer greater than 1.
[0118] FIG. 15 is a diagram illustrating a wireless communication
device 1500.
[0119] Referring to FIG. 15, wireless communication device 1500
comprises an identification module 1505 configured to identify a
PUCCH format as in S1405, and a transmission module 1510 configured
to transmit the UCI as in S1410. Wireless communication device 1500
may further comprise additional modules configured to perform
additional functions as described above in relation to FIG. 14, for
instance.
[0120] As used herein, the term "module" denotes any suitable
combination of hardware and/or software configured to perform a
designated function. For instance, the modules in FIG. 15 and other
figures may be implemented by at least one processor and memory,
one or more controllers, etc.
[0121] FIG. 16 is a flowchart illustrating a method 1600 of
operating a radio access node. The method of FIG. 16 could be
performed by a radio access node as illustrated in any of FIG. 11,
13 or 17, for instance.
[0122] Referring to FIG. 16, method 1600 comprises identifying a
physical uplink control channel (PUCCH) format to be used by at
least one wireless communication device for transmission of uplink
control information (UCI) in unlicensed spectrum, wherein the PUCCH
format is short PUCCH or long PUCCH, wherein the short PUCCH
occupies less than 1 subframe in the time domain and spans an
entire system bandwidth in the frequency domain with interlacing on
a resource block level, and wherein the long PUCCH occupies one
subframe in the time domain and spans the entire system bandwidth
in the frequency domain with interlacing on a resource block level
(S1605), and receiving the UCI from the at least one wireless
communication device in accordance with the identified PUCCH format
(S1610).
[0123] In certain embodiments, identifying the PUCCH format
comprises selecting between short PUCCH and long PUCCH according to
at least one of an eNodeB timing configuration and a hybrid
automatic repeat request (HARM) protocol.
[0124] In certain embodiments, the received UCI is multiplexed on
the same interlace as the short PUCCH or the long PUCCH with
information transmitted from at least one other wireless
communication device.
[0125] In certain embodiments, the PUCCH format is short PUCCH and
the short PUCCH comprises at least one demodulation reference
signal (DMRS) symbol and at least one control-data symbol in the
time domain. In certain related embodiments, the short PUCCH
comprises a sequence of symbols at the end of a downlink partial
subframe.
[0126] In certain embodiments, the received UCI is multiplexed in
the short PUCCH or long PUCCH with information transmitted from at
least one other wireless communication device. In certain related
embodiments, the UCI and the information transmitted from the at
least one other wireless communication device are multiplexed using
orthogonal cover codes (OCC) and cyclic shifts (CS) on control-data
symbols and reference symbols, respectively.
[0127] In certain embodiments, the PUCCH format comprises a
demodulation reference signal (DMRS) symbol on all subcarriers
within a block-interleaved frequency division multiple access
(B-IFDMA) symbol on an assigned interlace or on all assigned
interlaces across the entire system bandwidth. In certain
embodiments, the PUCCH format comprises a demodulation reference
signal (DMRS) symbol once per "n" subcarriers with a pattern that
can be shifted or unshifted on different B-IFDMA symbols, where "n"
is an integer greater than 1.
[0128] In certain embodiments, the UCI is multiplexed with UCI from
at least one other wireless communication device using different
interlacing patterns within the same subframe.
[0129] In certain embodiments, the UCI is multiplexed with UCI from
at least one other wireless communication device using the same
interlacing pattern within the same subframe. In certain related
embodiments, the UCI from the at least one wireless communication
device and the at least one other wireless communication device are
subject to different orthogonal cover codes (OCC).
[0130] FIG. 17 is a diagram illustrating a radio access node
1700.
[0131] Referring to FIG. 17, radio access node 1700 comprises a
determining module 1705 configured to determine or identify a PUCCH
format as in S1605, and a receiving/decoding module 1710 configured
to receive and decode the UCI as in S1610. Radio access node 1700
may further comprise additional modules configured to perform
additional functions as described above in relation to FIG. 16, for
instance.
[0132] As indicated by the foregoing, certain embodiments of the
disclosed subject matter provide two PUCCH formats to be
transmitted on carriers in unlicensed spectrum for LAA/Standalone
LTE-U. Both formats use interlaced UL resources and can be
multiplexed with other PUCCH/PUSCH UEs.
[0133] The following abbreviations are used in this description.
[0134] CCA Clear Channel Assessment [0135] CRS Cell-Specific
Reference Signal [0136] CSI Channel State Information [0137] DCI
Downlink Control Information [0138] DL Downlink [0139] DS Data
Symbol [0140] eNB evolved NodeB, base station [0141] UE User
Equipment [0142] UL Uplink [0143] LAA Licensed-Assisted Access
[0144] RS Reference Signal [0145] SCell Secondary Cell [0146] LBT
Listen-before-talk [0147] LTE-U LTE in Unlicensed Spectrum [0148]
PUSCH Physical Uplink Shared Channel [0149] PUCCH Physical Uplink
Control Channel [0150] UCI Uplink Control Information
[0151] While the disclosed subject matter has been presented above
with reference to various embodiments, it will be understood that
various changes in form and details may be made to the described
embodiments without departing from the overall scope of the
disclosed subject matter.
* * * * *