U.S. patent application number 16/871887 was filed with the patent office on 2020-08-27 for network node user device and methods thereof.
The applicant listed for this patent is HUAWEI TECHNOLOGIES CO., LTD.. Invention is credited to Fredrik BERGGREN.
Application Number | 20200275433 16/871887 |
Document ID | / |
Family ID | 1000004816430 |
Filed Date | 2020-08-27 |
United States Patent
Application |
20200275433 |
Kind Code |
A1 |
BERGGREN; Fredrik |
August 27, 2020 |
NETWORK NODE USER DEVICE AND METHODS THEREOF
Abstract
A network node and a user device are provided. The network node
comprises: a processor configured to allocate a plurality of
Physical Resource Blocks (PRBs) for a Physical Uplink Control
Channel (PUCCH) having a PUCCH format defined for two or more PRBs,
wherein the allocated plurality of PRBs are associated with a user
device; a transceiver configured to signal allocation information
to the user device, wherein the allocation information comprises a
frequency location and a number of allocated plurality of PRBs. The
user device comprises: a processor configured to determine uplink
control information for one or more network nodes; a transceiver
configured to transmit the uplink control information in a PUCCH to
the one or more network nodes, wherein a plurality of PRBs are
allocated for the PUCCH and wherein the PUCCH has a PUCCH format
defined for two or more PRBs.
Inventors: |
BERGGREN; Fredrik; (Kista,
SE) |
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Applicant: |
Name |
City |
State |
Country |
Type |
HUAWEI TECHNOLOGIES CO., LTD. |
Shenzhen |
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CN |
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Family ID: |
1000004816430 |
Appl. No.: |
16/871887 |
Filed: |
May 11, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15722684 |
Oct 2, 2017 |
10660073 |
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16871887 |
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PCT/EP2015/057566 |
Apr 8, 2015 |
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15722684 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W 74/004 20130101;
H04W 72/0413 20130101; H04W 72/1284 20130101; H04W 72/042 20130101;
H04W 72/1268 20130101 |
International
Class: |
H04W 72/04 20060101
H04W072/04; H04W 74/00 20060101 H04W074/00; H04W 72/12 20060101
H04W072/12 |
Claims
1. A network node for a wireless communication system, the network
node comprising: a processor configured to allocate a plurality of
Physical Resource Blocks (PRBs) for a Physical Uplink Control
Channel (PUCCH) having a PUCCH format defined for two or more PRBs,
wherein the plurality of PRBs are associated with a user device;
and a transceiver configured to signal allocation information to
the user device, wherein the allocation information comprises: a
frequency location; a number of PRBs in the plurality of PRBs; and
at least one of a modulation type and a modulation level for the
plurality of PRBs, wherein at least one of the frequency location
and the number of PRBs in the plurality of PRBs is jointly encoded
with at least one of the modulation type and the modulation
level.
2. The network node according to claim 1, wherein at least two PRBs
of the plurality of PRBs are contiguously located in a frequency
domain and within the same time slot.
3. The network node according to claim 1, wherein at least two PRBs
of the plurality of PRBs are located at the same frequency and
within different contiguous time slots.
4. The network node according to claim 1, wherein the allocation
information is signalled as physical layer signalling in a downlink
control channel, or as higher layer signalling, or as a combination
thereof.
5. The network node according to claim 1, wherein the allocation
information is signalled as indices or bitmaps.
6. The network node according to claim 5, wherein the allocation
information is signalled as indices, and wherein each index is
associated with a set of PRBs contiguously located in a frequency
domain and configured by higher layers.
7. The network node according to claim 6, wherein there are at
least two sets of PRBs having different sizes.
8. The network node according to claim 1, wherein the transceiver
is further configured to receive uplink control information in the
PUCCH from the user device in response to signalling the allocation
information.
9. A user device for a wireless communication system, the user
device comprising: a processor configured to determine uplink
control information for one or more network nodes; a transceiver
configured to: transmit the uplink control information in a Uplink
Control Channel (PUCCH) to the one or more network nodes, wherein a
plurality of Physical Resource Blocks (PRBs) are allocated to the
user device for the PUCCH, and wherein the PUCCH has a PUCCH format
defined for two or more PRBs; receive allocation information from
the one or more network nodes in physical layer signalling, or in
higher layer signalling, or in a combination thereof; and transmit
the uplink control information in the PUCCH according to the
allocation information; wherein the allocation information
comprises: a frequency location; a number of PRBs in the plurality
of PRBs; and at least one of a modulation type and a modulation
level for the plurality of PRBs, wherein at least one of the
frequency location and the number of PRBs in the plurality of PRBs
is jointly encoded with at least one of the modulation type and the
modulation level.
10. The user device according to claim 9, wherein at least two PRBs
of the plurality of PRBs are contiguously located in a frequency
domain and within the same time slot.
11. The user device according to claim 9, wherein at least two PRBs
of the plurality of PRBs are located at the same frequency and
within different contiguous time slots.
12. The user device according to claim 9, wherein the allocation
information is signalled as indices or bitmaps.
13. The user device according to claim 12, wherein the allocation
information is signalled as indices, and wherein each index is
associated with a set of PRBs contiguously located in a frequency
domain and configured by higher layers.
14. A method for a wireless communication system, the method
comprising: allocating a plurality of Physical Resource Blocks
(PRBs) for a Physical Uplink Control Channel (PUCCH) having a PUCCH
format defined for two or more PRBs, wherein the plurality of PRBs
are associated with a user device; signalling allocation
information to the user device, wherein the allocation information
comprises: a frequency location; a number of PRBs in the plurality
of PRBs; and at least one of a modulation type and a modulation
level for the plurality of PRBs, wherein at least one of the
frequency location and the number of PRBs in the plurality of PRBs
is jointly encoded with at least one of the modulation type and the
modulation level.
15. The method according to claim 14, wherein at least two PRBs of
the plurality of PRBs are: contiguously located in a frequency
domain and within the same time slot; or located at the same
frequency and within different contiguous time slots.
16. A method for a wireless communication system, the method
comprising: determining uplink control information for one or more
network nodes; transmitting the uplink control information in a
Uplink Control Channel (PUCCH) to the one or more network nodes,
wherein a plurality of Physical Resource Blocks (PRBs) are
allocated for the PUCCH, and wherein the PUCCH has a PUCCH format
defined for two or more PRBs; receiving allocation information from
the one or more network nodes in physical layer signalling, or in
higher layer signalling, or in a combination thereof; and
transmitting the uplink control information in the PUCCH according
to the allocation information; wherein the allocation information
comprises: a frequency location; a number of PRBs in the plurality
of PRBs; and at least one of a modulation type and a modulation
level for the plurality of PRBs, wherein at least one of the
frequency location and the number of PRBs in the plurality of PRBs
is jointly encoded with at least one of the modulation type and the
modulation level.
17. The method according to claim 16, wherein at least two PRBs of
the plurality of PRBs are contiguously located in a frequency
domain and within the same time slot.
18. The method according to claim 16, wherein at least two PRBs of
the plurality of PRBs are located at the same frequency and within
different contiguous time slots.
19. A non-transitory computer readable medium including a computer
program with a computer readable program code for performing the
method according to claim 14 when the computer program runs on a
computer.
20. A non-transitory computer readable medium including a computer
program with a computer readable program code for performing the
method according to claim 16 when the computer program runs on a
computer.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 15/722,684, filed on Oct. 2, 2017, which is a
continuation of International Application No. PCT/EP2015/057566,
filed on Apr. 8, 2015. All of the afore-mentioned patent
applications are hereby incorporated by reference in their
entireties.
TECHNICAL FIELD
[0002] The present disclosure relates to a network node and a user
device. Furthermore, the present disclosure also relates to
corresponding methods, a computer program, and a computer program
product.
BACKGROUND
[0003] UpLink (UL) control channels are utilized to provide the
base station with Hybrid Automatic Repeat reQuest (HARQ) feedback
in response to DownLink (DL) data transmissions, Scheduling Request
(SR) for the uplink as well as Channel State Information (CSI)
reports corresponding to downlink carriers. For carrier
aggregation, the Uplink Control Information (UCI) overhead can
become extensive, considering the User Equipment (UE) can be
scheduled on multiple downlink carriers simultaneously, which not
only increases the HARQ feedback but also the need for more CSI
reports to assist the scheduling.
[0004] The UCI overhead is even more severe for Time Division
Duplex (TDD) systems, since there are typically less uplink
subframes available than downlink subframes, which implies that the
UCI payload becomes larger per transmission attempt of the uplink
control channel. In Long Term Evolution Advanced (LTE-Advanced)
Rel-12, a UE can be configured to aggregate up to 5 serving cells
(i.e., different carriers in an eNodeB), where a serving cell
comprises at least a downlink component carrier and where each
carrier has at most 20 MHz bandwidth. The UE is always configured
with a UE-specific primary serving cell having both a downlink and
uplink component carrier. The uplink control channel is transmitted
on the primary serving cell. Additionally, a UE can be configured
to aggregate up to 4 UE-specific secondary serving cells.
[0005] The Physical Uplink Control Channel (PUCCH) in LTE-Advanced
comprises several PUCCH formats, e.g., formats 1/1a/1b/2/2a/2b/3,
each being used for a particular purpose of SR transmission, HARQ
feedback and periodic CSI reporting. The payload of these PUCCH
formats range from 1 to 22 information bits. PUCCH formats
1/1a/1b/2/2a/2b are based on modulated sequences, while PUCCH
format 3 is using Discrete Fourier Transform (DFT) spread
transmission. Several of the PUCCH formats also include Code
Division Multiplexing (CDM) transmission, such that multiple UEs
could be transmitting the PUCCH on the same Physical Resource Block
(PRB) pair by utilizing different sequences. PUCCH formats
1/1a/1b/2/2a/2b could share the same PRB pair, while PUCCH format 3
PRB pairs cannot be shared with other PUCCH formats. A
characterizing feature is that all the PUCCH formats utilize QPSK
modulation and occupy only 1 PUCCH region, which comprises one PRB
pair.
[0006] The resource allocation includes providing the UE with
information such that it can derive what sequences and PRB pairs it
should use for the PUCCH transmission. The PUCCH resources for
PUCCH formats 2/2a/2b are semi-statically configured and would
typically be located at the outer PUCCH regions close to the edge
of the carrier. These formats are primarily used for periodic CSI
reporting. The PUCCH resources for PUCCH formats 1a/1b can be
derived implicitly from the PDCCH or the Enhanced Physical Downlink
Control Channel (EPDCCH) that was used for scheduling the
associated Physical Downlink Shared Channel (PDSCH). Thus, they are
allocated dynamically on a need basis. PUCCH resources for PUCCH
formats 1a/1b could also be semi-statically configured for the case
where there is no associated PDCCH/EPDCCH, e.g., for
Semi-Persistent Scheduling (SPS). Typically, up to 18 UEs could be
multiplexed within a PBR pair, utilizing different cyclic shifts of
the transmitted sequence to achieve CDM transmission. PUCCH format
3 can, e.g., be used if the UE is scheduled on at least one
secondary serving cell. Up to 5 UEs can be multiplexed within a PRB
pairs by utilizing different spreading codes. A set of
semi-statically PUCCH resources is configured for PUCCH format 3
and a resource is dynamically indicated from this set by an
indicator in the associated PDCCH/EPDCCH on a secondary cell. If
the UE is only scheduled on its primary serving cell, it is using
PUCCH formats 1/1a/1b resources.
SUMMARY
[0007] An objective of embodiments of the present disclosure is to
provide a solution which mitigates or solves the drawbacks and
problems of conventional solutions.
[0008] An "or" in this description and the corresponding claims is
to be understood as a mathematical OR which covers "and" and "or",
and is not to be understand as an XOR (exclusive OR).
[0009] The above objectives are solved by the subject matter of the
independent claims. Further advantageous implementation forms of
the present disclosure can be found in the dependent claims.
[0010] According to a first aspect of the disclosure, the above
mentioned and other objectives are achieved with a network node for
a wireless communication system, the network node comprising:
[0011] a processor configured to allocate a plurality of Physical
Resource Blocks, PRBs, for a Physical Uplink Control Channel,
PUCCH, having a PUCCH format defined for two or more PRBs, wherein
the allocated plurality of PRBs are associated with a user
device;
[0012] a transceiver configured to signal allocation information to
the user device, wherein the allocation information comprises a
frequency location and a number of allocated plurality of PRBs.
[0013] With a network node having the capabilities to allocate a
PUCCH having a PUCCH format defined for two or more PRBs and to
transmit the allocation information to a user device a number of
advantages are provided.
[0014] An advantage is that the present network node provides the
ability of accommodating large UCI payloads on the PUCCH by
utilizing two or more PRB pairs and also improved and flexible
PUCCH resource utilization by signalling the locations and numbers
of the allocated PRBs to the user device. Therefore, the present
network node provides the advantage of flexible allocation of the
PRB pairs in terms of determining the number of PRB pairs as well
as the positions in both time and frequency domains. Thus, it
renders that fewer PRB pairs need to be reserved since the network
node could allocate a minimum number of PRB pairs for accommodating
the UCI payload while offering sufficient UCI detection
performance. Moreover, savings in number of PRB pairs can be
achieved by configuring overlapping PRB pairs for different PUCCH
formats and using allocation information conveyed in the downlink
control channel to avoid resource collisions.
[0015] In a first possible implementation form of a network node
according to the first aspect, at least two of the allocated
plurality of PRBs are contiguously located in the frequency domain
and within the same time slot.
[0016] A time slot should in this disclosure be understood as a
time resource of a wireless communication system. The time slot can
therefore be considered as a time resource defined in a suitable
time unit. For example, in LTE the time slot has duration of 0.5 ms
and two time slots comprise one subframe of 1 ms. However, the time
slot of the present disclosure may have a shorter or a longer time
duration than 0.5 ms.
[0017] Advantages of this first possible implementation form of the
first aspect include the possibility to perform Discrete Fourier
Transform (DFT) precoding on the plurality of contiguous PRBs which
results in a signal with low Peak-to-Average-Power-Ratio (PAPR).
This allows the network node to reduce the power back-off which
improves the probability of the network node to correctly receive
the PUCCH and the UCI sent from the user device.
[0018] In a second possible implementation form of a network node
according to the first possible implementation form of the first
aspect or to the first aspect as such, at least two of the
allocated plurality of PRBs are located at the same frequency and
within different contiguous time slots.
[0019] Advantages of this second possible implementation form of
the first aspect include the possibility to interpolate channel
estimates between the different time slots. This results in better
channel estimates which improves the probability of the network
node to correctly receive the uplink control information from the
user device.
[0020] In a third possible implementation form of a network node
according to any of the preceding possible implementation forms of
the first aspect or to the first aspect as such, the allocation
information further comprises at least one of a modulation type and
a modulation level for the allocated plurality of PRBs.
[0021] Advantages of this third possible implementation form of the
first aspect include the possibility for better PUCCH resource
utilization by adapting the payload to a modulation type or a
modulation level, which may result in a need for fewer PRBs or PRB
pairs and improved detection performance of the PUCCH.
[0022] In a fourth possible implementation form of a network node
according to the third possible implementation form of the first
aspect or to the first aspect as such, at least one of the
frequency location and the number of allocated plurality of PRBs is
jointly encoded with at least one of the modulation type and the
modulation level.
[0023] Advantages of this fourth possible implementation form of
the first aspect include the possibility to reduce the amount of
bits needed for the transceiver to signal the allocation
information. Therefore, overhead is reduced in the wireless
communication system.
[0024] In a fifth possible implementation form of a network node
according to any of the preceding possible implementation forms of
the first aspect or to the first aspect as such, the allocation
information is signalled as physical layer signalling in a downlink
control channel (e.g., by bits in a Downlink Control Information
(DCI) format), or as higher layer signalling (e.g., by
bits/information delivered by Radio Resource Control (RRC)
signalling), or as a combination thereof (e.g., by associating bits
in a DCI with RRC configured PRB pairs).
[0025] Advantages of this fifth possible implementation form of the
first aspect include the possibility to reduce the amount of bits
needed for the transceiver to signal the allocation information.
Therefore, overhead is reduced in the wireless communication
system.
[0026] In a sixth possible implementation form of a network node
according to any of the preceding possible implementation forms of
the first aspect or to the first aspect as such, the allocation
information is signalled as indices or bitmaps.
[0027] Advantages of this sixth possible implementation form of the
first aspect include the possibility to reduce the amount of
signalling needed for the transceiver to signal the allocation
information, while offering flexible allocations. Therefore,
overhead is reduced in the wireless communication system.
[0028] In a further possible implementation form of a network node
according to the sixth possible implementation form of the first
aspect, each index is associated with a bitmap and/or each index is
signalled with bits in a downlink control channel.
[0029] Therefore, overhead is reduced in the wireless communication
system with these implementation forms of the first aspect.
[0030] In a seventh possible implementation form of a network node
according to the sixth possible implementation form of the first
aspect or to the first aspect as such, each index is associated
with a set of allocated PRBs contiguously located in the frequency
domain and configured by higher layers.
[0031] Advantages of this seventh possible implementation form of
the first aspect include the possibility to reduce the amount of
signalling on a downlink control channel for providing the
allocation information. Therefore, overhead is reduced in the
wireless communication system.
[0032] In an eighth possible implementation form of a network node
according to the seventh possible implementation form of the first
aspect or to the first aspect as such, there are at least two sets
of allocated PRBs having different sizes.
[0033] Advantages of this eighth possible implementation form of
the first aspect include the possibility to utilize different
numbers of PRBs or PRB pairs depending on, e.g., the UCI payload.
This implies allocation flexibility, reduced overhead and adaption
to different transmission conditions and requirements.
[0034] In a ninth possible implementation form of a network node
according to any of the preceding possible implementation forms of
the first aspect or to the first aspect as such,
[0035] the transceiver further is configured to receive uplink
control information in the PUCCH from the user device in response
to signalling the allocation information.
[0036] Advantages of this eighth possible implementation form of
the first aspect include that the wireless communication system can
take full advantage of the new PUCCH format according to the
present solution since the user device makes transmissions
according to the new PUCCH format.
[0037] According to a second aspect of the disclosure, the above
mentioned and other objectives are achieved with a user device for
a wireless communication system, the user device comprising:
[0038] a processor configured to determine uplink control
information for one or more network nodes;
[0039] a transceiver configured to transmit the uplink control
information in a PUCCH to the one or more network nodes, wherein a
plurality of PRBs are allocated for the PUCCH and wherein the PUCCH
has a PUCCH format defined for two or more PRBs.
[0040] The present user device according to the second aspect being
capable of transmitting uplink control information in PUCCH having
a PUCCH format defined for two or more PRBs provides a number of
advantages.
[0041] An advantage with the user device according to the second
aspect include that the user device can transmit the new PUCCH
thereby making possible the support of increased number of
supported carriers since the payload capacity can be increased.
Also payload flexibility of the PUCCH is provided.
[0042] In a first possible implementation form of a user device
according to the second aspect,
[0043] the transceiver further is configured to receive allocation
information from the one or more network nodes in physical layer
signalling or in higher layer signalling or in a combination
thereof, wherein the allocation information comprises a frequency
location and a number of allocated plurality of PRBs;
[0044] the transceiver further is configured to transmit the uplink
control information in the PUCCH according to the allocation
information.
[0045] An advantage with this first implementation form of the
second aspect include that the PUCCH transmission of the user
device can be dynamically or semi-statically controlled. This means
that the PUCCH transmissions can be adapted to e.g., radio access
network and environmental conditions implying improved performance
and increased throughput. Further, even more payload flexibility of
the PUCCH is provided with first implementation form of the second
aspect.
[0046] According to a third aspect of the disclosure, the above
mentioned and other objectives are achieved with a method for a
wireless communication system, the method comprising:
[0047] allocating a plurality of PRBs for a PUCCH having a PUCCH
format defined for two or more PRBs, wherein the allocated
plurality of PRBs are associated with a user device;
[0048] signalling allocation information to the user device,
wherein the allocation information comprises a frequency location
and a number of allocated plurality of PRBs for the PUCCH
format.
[0049] In a first possible implementation form of a method
according to the third aspect, at least two of the allocated
plurality of PRBs are contiguously located in the frequency domain
and within the same time slot.
[0050] In a second possible implementation form of a method
according to the first possible implementation form of the third
aspect or to the third aspect as such, at least two of the
allocated plurality of PRBs are located at the same frequency and
within different contiguous time slots.
[0051] In a third possible implementation form of a method
according to any of the preceding possible implementation forms of
the third aspect or to the third aspect as such, the allocation
information further comprises at least one of a modulation type and
a modulation level for the allocated plurality of PRBs.
[0052] In a fourth possible implementation form of a method
according to the third possible implementation form of the third
aspect or to the third aspect as such, at least one of the
frequency location and the number of allocated plurality of PRBs is
jointly encoded with at least one of the modulation type and the
modulation level.
[0053] In a fifth possible implementation form of a method
according to any of the preceding possible implementation forms of
the third aspect or to the third aspect as such, the allocation
information is signalled as physical layer signalling in a downlink
control channel, or as higher layer signalling, or as a combination
thereof.
[0054] In a sixth possible implementation form of a method
according to any of the preceding possible implementation forms of
the third aspect or to the third aspect as such, the allocation
information is signalled as indices or bitmaps.
[0055] In a further possible implementation form of a method
according to the sixth possible implementation form of the third
aspect, each index is associated with a bitmap and/or each index is
signalled with bits in a downlink control channel.
[0056] In a seventh possible implementation form of a method
according to the sixth possible implementation form of the third
aspect or to the third aspect as such, each index is associated
with a set of allocated PRBs contiguously located in the frequency
domain and configured by higher layers.
[0057] In an eighth possible implementation form of a method
according to the seventh possible implementation form of the third
aspect or to the third aspect as such, there are at least two sets
of allocated PRBs having different sizes.
[0058] In a ninth possible implementation form of a method
according to any of the preceding possible implementation forms of
the third aspect or to the third aspect as such, the method further
comprises
[0059] receiving uplink control information in the PUCCH from the
user device in response to signalling the allocation
information.
[0060] According to a fourth aspect of the disclosure, the above
mentioned and other objectives are achieved with a method for a
wireless communication system, the method comprising:
[0061] determining uplink control information for one or more
network nodes;
[0062] transmitting the uplink control information in a PUCCH to
the one or more network nodes, wherein a plurality of PRBs are
allocated for the PUCCH and wherein the PUCCH has a PUCCH format
defined for two or more PRBs.
[0063] In a first possible implementation form of a method
according to the fourth aspect, the method further comprises
[0064] receiving allocation information from the one or more
network nodes in physical layer signalling or in higher layer
signalling or in a combination thereof, wherein the allocation
information comprises a frequency location and a number of
allocated plurality of PRBs;
[0065] transmitting the uplink control information in the PUCCH
according to the allocation information.
[0066] The advantages of the methods according to the third aspect
or the fourth aspect are the same as those for the corresponding
device claims according to the first and second aspects.
[0067] The present disclosure also relates to a computer program,
characterized in code means, which when run by processing means
causes said processing means to execute any method according to the
present disclosure. Further, the disclosure also relates to a
computer program product comprising a computer readable medium and
said mentioned computer program, wherein said computer program is
included in the computer readable medium, and comprises of one or
more from the group: ROM (Read-Only Memory), PROM (Programmable
ROM), EPROM (Erasable PROM), Flash memory, EEPROM (Electrically
EPROM) and hard disk drive.
[0068] Further applications and advantages of the present
disclosure will be apparent from the following detailed
description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0069] The appended drawings are intended to clarify and explain
different embodiments of the present disclosure, in which:
[0070] FIG. 1 shows PUCCH regions;
[0071] FIG. 2 shows a first network node according to an embodiment
of the present disclosure;
[0072] FIG. 3 shows a method according to an embodiment of the
present disclosure;
[0073] FIG. 4 shows a second network node according to an
embodiment of the present disclosure;
[0074] FIG. 5 shows another method according to an embodiment of
the present disclosure;
[0075] FIG. 6 shows a wireless communication system according to an
embodiment of the present disclosure;
[0076] FIG. 7 illustrates an example of resource allocation for
PUCCH formats according to an embodiment of the present
disclosure;
[0077] FIG. 8 illustrates a further example of resource allocation
for PUCCH formats according to an embodiment of the present
disclosure;
[0078] FIG. 9 illustrates a further example of resource allocation
for PUCCH formats according to an embodiment of the present
disclosure; and
[0079] FIG. 10 illustrates a further example of resource allocation
for PUCCH formats according to an embodiment of the present
disclosure.
DETAILED DESCRIPTION
[0080] The inventor has identified a number of issues and drawbacks
of conventional techniques, such as related art LTE and
LTE-Advanced, which are solved by embodiments of the present
disclosure.
[0081] As more spectrum becomes available, e.g., in higher
frequency bands or in unlicensed frequency bands, it would be
beneficial to introduce UEs with capability of aggregating more
than 5 serving cells. Also, LTE-Advanced Rel-13 is supposed to
support aggregation up to 32 serving cells for a UE, i.e.,
simultaneous reception of up to 32 component carriers. This
significantly increases the UCI feedback and calls for new
mechanisms for transmitting the UCI, e.g., new design of uplink
control channels. In addition to increasing the payload capacity of
the uplink control channel, it is also important to consider its
time-frequency resource allocation. Since the uplink also comprises
data channels, it is crucial to minimize the resource usage of the
uplink control channel as well as provide efficient multiplexing
between the data and control channels in the uplink. Moreover, the
UE needs to be able to determine which time-frequency resources it
should use for transmitting the uplink control channels. Therefore,
a new mechanism for transmitting larger UCI payloads need to
include an efficient uplink control channel resource reservation
scheme.
[0082] It is further realized that the UCI payload can vary
significantly depending on the carrier configurations. For example,
if spatial multiplexing is assumed for the PDSCH, 2 HARQ
information feedback bits need to be transmitted per carrier, i.e.,
1 bit per transport block. Moreover, for Time Division Duplex (TDD)
the number of HARQ information feedback bits depends on the UL
subframe index and the UL/DL TDD configuration. Similarly, the CSI
payload depends on the CSI reporting mode of each component
carrier. Therefore, the UCI payload can vary significantly, from a
few tens of bits to several hundreds of bits, depending on the
configurations of the carrier aggregation. For efficient PUCCH
resource utilization, it could therefore be considered to adapt the
payload capacity of the PUCCH to the number of input UCI bits.
[0083] A first issue is that the existing PUCCH formats do not
offer sufficient UCI payload capacity if carrier aggregation up to
32 downlink component carriers should be supported. For example,
when aggregating 32 Frequency Division Duplex (FDD) component
carriers and using Multiple Input Multiple Output (MIMO)
transmission, 64 HARQ information feedback bits need to be
accommodated (i.e., 2 HARQ-ACK bits per component carrier).
Moreover, when aggregating 32 TDD component carriers with TDD UL/DL
configuration 5 and using MIMO transmission, 576 HARQ information
feedback bits need to be accommodated.
[0084] There would typically be two options for accommodating a
larger UCI payload, which potentially also could be combined: HARQ
information (e.g., ACK or NACK or DTX) could be compressed by
bundling the HARQ bits, that is performing a logical AND operation
among the bits. The drawback of this is an increased number of
unnecessary retransmissions (i.e., reduced downlink throughput),
since any ACK that is bundled with a NACK/DTX would result in a
bundled NACK. Another option, e.g., for the CSI reports, is to drop
information. For example, if the payload becomes too large, certain
CSI reports are prioritized according to some rules. The drawback
of this is that it takes longer for the eNodeB to retrieve CSI
reports for all carriers. By increasing the amount of
time-frequency resources, a higher payload capacity could be
obtained. This could be achieved by using more than 1 PRB pair for
a PUCCH transmission, or reducing the UE multiplexing capacity of
the PUCCH format. Another option is to increase the modulation
level, e.g., to 16 QAM. The existing PUCCH formats do not allow
multiple PRB pair allocations or usage of multiple modulation
levels.
[0085] A second issue is that, a new PUCCH resource reservation
scheme would be needed if a new PUCCH format is designed. A new
PUCCH format could require a separate set of PUCCH resources, such
that existing PUCCH resource reservation schemes are not
applicable. The existing PUCCH resource allocation schemes are
inflexible in at least two aspects: a new PUCCH format capable of a
larger payload may benefit from utilizing DFT-precoding such that
the resulting waveform is Single Carrier Frequency Division
Multiplex Access (SC-FDMA), which reduces the power dynamics of the
transmitted signal. Therefore, such a PUCCH format needs to be
transmitted on two or more contiguous PRBs within a time slot. That
would require joint allocation of PUCCH regions k, k+2, . . . ,
which is not supported in LTE.
[0086] A PUCCH region comprises different frequency locations of
the PRBs in the two time slots. The benefit from this is increased
frequency diversity. On the other hand, that makes it impossible to
interpolate channel estimates obtained from reference signals in
the two respective PRBs. A new PUCCH format capable of a larger
payload may benefit from being able to use the same PRB in the two
time slots. This may reduce the frequency diversity but could make
it possible to reduce the reference signal overhead, since it
becomes possible to interpolate channel estimates obtained from
reference signals in the two respective PRBs. The existing PUCCH
resource allocation schemes do not support using the same PRB in
both time slots. The PUCCH in LTE-Advanced comprises several PUCCH
formats (e.g., formats 1/1a/1b/2/2a/2b/3), each being used for a
particular purpose of SR transmission, HARQ feedback and periodic
CSI reporting. The payload of these PUCCH formats range from 1 to
22 information bits. PUCCH formats 1/1a/1b/2/2a/2b are based on
modulated sequences, while PUCCH format 3 is using DFT-spread
transmission. Several of the PUCCH formats also include CDM
transmission, such that multiple UEs could be transmitting the
PUCCH on the same PRB pair by utilizing different sequences. PUCCH
formats 1/1a/1b/2/2a/2b could share the same PRB pair, while PUCCH
format 3 PRB pairs cannot be shared with other PUCCH formats. A
characterizing feature is that all the PUCCH formats utilize QPSK
modulation and occupy only 1 PUCCH region, which comprises one PRB
pair. FIG. 1 shows an example of the location of 12 PUCCH regions,
m=0, 1, . . . , 11, in a subframe (i.e., two time slots) for a
carrier having M PRBs. A PRB comprises 180 kHz and 0.5 ms (i.e.,
one time slot). A PUCCH region comprises 1 PRB in the first time
slot and 1 PRB in the second time slot.
[0087] A third issue is that the UCI payload may vary
significantly. The UCI payload may be different depending on if it
comprises HARQ-ACK information and/or CSI reports. Such payload
variations may occur on subframe level depending on how many
serving cells that are scheduled and how the periods of the CSI
reports are arranged. Thus, it can be anticipated that in certain
subframes, the UCI payload will be comparatively smaller than in
other subframes.
[0088] To solve the above and further issues and drawbacks
embodiments of the present disclosure relates to a network node, a
user device, a wireless communication system, and methods
thereof.
[0089] FIG. 2 shows a network node 100 according to an embodiment
of the present disclosure. The network node 100 has the
capabilities to communicate in a wireless communication system 500
as illustrated in FIG. 2. The network node 106 includes one or more
optional antennas 106 which are coupled to a transceiver 104 of the
network node 100. The network node 100 further comprises a
processor 102 communicably coupled with the transceiver 104 by
means of communication means known in the art. The processor 102 of
the network node 100 is configured to allocate a plurality of PRBs
for the present PUCCH. The present PUCCH has at least one new PUCCH
format that is defined for two or more PRBs. The allocated
plurality of PRBs are associated with a user device 300 (see FIG.
4) of the wireless communication system 500. This means that the
allocated plurality of PRBs are intended to be used by the user
device 300 for transmission of uplink control information. It
should however be noted that the same PRBs may be allocated to more
than one user device 300 if code division multiplexing or other
orthogonal multiplexing methods are used.
[0090] The transceiver 104 of the network node 100 is configured to
signal allocation information to the user device 300. The mentioned
allocation information comprises information about the allocation
of the plurality of PRBs for the PUCCH. The allocation information
at least comprises the frequency location of the allocated
plurality of PRBs and the number of allocated plurality of
PRBs.
[0091] The present network node 100, or base station, e.g. a Radio
Base Station (RBS), which in some networks may be referred to as
transmitter, "eNB", "eNodeB", "NodeB" or "B node", depending on the
communication technology and terminology used. The radio network
nodes may be of different classes such as e.g. macro eNodeB, home
eNodeB or pico base station, based on transmission power and
thereby also cell size. The radio network node can be a Station
(STA), which is any device that contains an IEEE 802.11-conformant
Media Access Control (MAC) and Physical Layer (PHY) interface to
the Wireless Medium (WM).
[0092] FIG. 3 shows a corresponding method 200 according to an
embodiment of the present disclosure. The method 200 may be
executed in a network node 100, such as the one shown in FIG. 2.
The method 200 comprises the step of allocating 202 a plurality of
PRBs for a PUCCH having the new PUCCH format defined for two or
more PRBs. The allocated plurality of PRBs are as mentioned above
associated with at least one user device 300. The method 200
finally comprises the step of signalling 204 allocation information
to the user device 300. The allocation information comprises the
frequency location of the allocated plurality of PRBs for the PUCCH
format and the number of allocated plurality of PRBs for the PUCCH
format.
[0093] In one embodiment of the present disclosure, the present
PUCCH format is defined for but is not limited to the cases of:
more than two PRBs; more than one PRB in one time slot; PRBs
associated with more than one PUCCH region; and to combinations
thereof of these three cases.
[0094] FIG. 4 shows a user device 300 according to an embodiment of
the present disclosure. The user device 300 comprises a processor
302 and a transceiver 304. The processor 302 is communicably
coupled with the transceiver 304 by means of communication means
known in the art. In the embodiment shown in FIG. 4 the user device
300 further comprises one or more optional antennas 306 coupled to
the transceiver 304. The processor 302 of the user device 300 is
configured to determine uplink control information for one or more
network nodes 100a, 100b, . . . , 100n (see FIG. 6). The control
information relates to information about the transmissions between
the user device 300 and the network node 100, such as SR
transmission, HARQ feedback and periodic CSI reporting. The
transceiver 304 of the user device 300 receives the uplink control
information from the processor 302 and is further configured to
transmit the uplink control information in the new PUCCH to the one
or more network nodes 100a, 100b, . . . , 100n. A plurality of PRBs
are allocated for the present PUCCH in which the user device 300
transmits the control information and the PUCCH has the new PUCCH
format defined for two or more PRBs as described above.
[0095] The User Device (UD) 300 or UE, mobile station, wireless
terminal and/or mobile terminal is enabled to communicate
wirelessly in a wireless communication system 500, sometimes also
referred to as a cellular radio system. The UE may further be
referred to as mobile telephones, cellular telephones, computer
tablets or laptops with wireless capability. The UEs in the present
context may be, for example, portable, pocket-storable, hand-held,
computer-comprised, or vehicle-mounted mobile devices, enabled to
communicate voice and/or data, via the radio access network, with
another entity, such as another receiver or a server. The UE can be
a Station (STA), which is any device that contains an IEEE
802.11-conformant Media Access Control (MAC) and Physical Layer
(PHY) interface to the Wireless Medium (WM)
[0096] FIG. 5 shows a corresponding method 400 according to an
embodiment of the present disclosure. The method 400 may be
executed in a user device 300, such as the one shown in FIG. 4. The
method 400 comprises the step of determining 402 uplink control
information for one or more network nodes 100a, 100b, . . . , 100n.
The method 400 finally comprises the step of transmitting 404 the
uplink control information in the present PUCCH to the one or more
network nodes 100a, 100b, . . . , 100n. A plurality of PRBs are
allocated for the PUCCH and the PUCCH has a PUCCH format defined
for two or more PRBs.
[0097] According to an embodiment of the present disclosure, the
transceiver 304 of the user device 300 is further configured to
receive allocation information from the one or more network nodes
100a, 100b, . . . , 100n in physical layer signalling or in higher
layer signalling or in a combination thereof. The allocation
information at least comprises as described above, in respect of
the network node 100, the frequency location and the number of
allocated plurality of PRBs for the PUCCH. Further, the transceiver
304 of the user device 300 is further configured to transmit the
uplink control information in the PUCCH according to the allocation
information. This means that the user device 300 transmits the
uplink control information in the frequency location(s) and the
number of allocated plurality of PRBs as given in the allocation
information. If further allocation information is included in the
allocation information the user device 300 will also transmit the
uplink control information according to that further allocation
information, e.g., modulation type and/or modulation level.
[0098] In the following description LTE or LTE-Advanced terminology
and context is used for describing further embodiments of the
present disclosure. It should however be noted that the network
node 100, user device 300 and methods 200, 400 of embodiments of
the present disclosure is not limited to mentioned LTE or
LTE-Advanced systems and can be used and applied in a multitude of
different wireless communication systems.
[0099] Generally, the present solution considers a new PUCCH format
which can be transmitted on at least 2 PRB pairs. In LTE-Advanced,
such a PUCCH format could, e.g., be based on extending PUCCH format
3 to multiple PRBs in a time slot or utilizing a Physical Uplink
Shared Channel (PUSCH) based structure with multiple PRBs in a time
slot. Typically, within a time slot, the at least 2 PRB pairs would
be located contiguously next to each other in the frequency domain
in order to preserve low power dynamics of the uplink control
channel. However, although the PUCCH format accommodates
transmission on at least 2 PRB pairs (e.g., at least 2 PRBs in one
time slot and at least 2 PRBs in another consecutive time slot)
embodiments of the present disclosure does not preclude that the
actual transmission is on 1 PRB pair only (e.g., 1 PRB in one time
slot and 1 PRB in another consecutive time slot). A skilled person
may also understand that the disclosure is applicable when the
PUCCH format which can be transmitted on at least two PRB pairs, is
alternatively represented as multiple PUCCH formats, where the
different PUCCH formats exhibit the same basic transmission
structure but are using different number of PRBs.
[0100] In one embodiment of the present disclosure the network node
100 provides the user device 300 with the information entity
.DELTA. from which the user device 300 can deduce properties for
the new PUCCH format. The information entity .DELTA. comprises
allocation information about the allocation of the PRBs of the
PUCCH format. The use of the information entity .DELTA. in this
disclosure is for the purpose for better understanding of the
present solution but is not limited thereof. This means that other
solutions without the use of the information entity .DELTA. are
possible.
[0101] In one embodiment of the present disclosure, the number of
PRB pairs used for the new PUCCH format is not variable, e.g., it
is always P (P>1) PRB pairs. Thus, information about the number
of allocated PRBs and/or frequency location of the allocated PRBs
can be obtained by a predefined rule(s) and does not need to be
provided by the network node 100 to the user device 300 by
signalling. This means that the user device 300 by knowing the
predefined rule also knows how, where and in which resources for
transmitting the uplink control information.
[0102] However, in another embodiment of the present disclosure,
the number of PRB pairs allocated for the transmission in the new
PUCCH format is variable and dynamic. This is advantageous for
minimizing the resource overhead and achieving sufficient detection
performance. The number of allocated PUCCH resources relate to the
number of coded bits on which the UCI can be transmitted. Thus,
since the UCI payload may vary, it is advantageous to allow the
eNodeB to control the number of allocated PUCCH resources as a
means to adjust the code rate (i.e., the ratio of the number of UCI
payload bits and coded bits). Embodiments of the present disclosure
is also applicable to the cases where the user device 300
determines the allocation information I about number of allocated
plurality of PRBs and frequency location of the allocated plurality
of PRBs only from .DELTA., or from .DELTA. and parameters that can
be obtained from the downlink control channel which schedules the
associated downlink data transmission, such as the Physical
Downlink Shared Channel (PDSCH). For example, in the former case
the allocation information can be a function such as I=f(.DELTA.),
and in the latter case the allocation information could be a
function I=f(.DELTA., n.sub.CCE), where n.sub.CCE is an index
derived from the time-frequency resources used for the associated
downlink control channel, e.g., PDCCH or EPDCCH.
[0103] FIG. 6 shows a wireless communication system 500 according
to an embodiment of the present disclosure. The wireless
communication system 500 comprises at least one network node 100
and at least one user device 300. However, a plurality of network
nodes 100a, 100b, . . . , 100n are shown in the example in FIG. 6.
The interaction between the user device 300 and the network nodes
100a, 100b, . . . , 100n is also illustrated in FIG. 6.
[0104] The network node 100a in FIG. 6 signals the allocation
information in the form of an information entity .DELTA. to the
user device 300 in the downlink. The signalling to the user device
300 can be in physical layer signalling or in higher layer
signalling or in a combination thereof which is more explained in
the following description. The user device 300 receives the
information entity .DELTA.. After determining uplink control
information the user device 300 transmits the uplink control
information in the PUCCH according to the allocation information in
the information entity .DELTA..
[0105] The uplink control information may be transmitted to only
network node 100a or also to the other network nodes 100b, . . . ,
100 of the wireless communication system 500. It is possible that
one network node 100 transmits the allocation information to the
user device 300 and that another network node 100 receives the
uplink control information. For example, network node 100a can
transmit the allocation information to the user device 300 and
network node 100b can receive the uplink control information from
the user device 100. Therefore, the transceiver 104 of the present
network node 100 is further configured to receive the uplink
control information in the new PUCCH format from the user device
300 in response to transmitting the allocation information to the
user device 300 according to a further embodiment.
[0106] In one embodiment of the present disclosure, the information
entity .DELTA. is configured by higher-layer signalling, e.g.,
Medium Access Control (MAC) or Radio Resource Control (RRC)
signalling. An advantage of this is the simplicity and low overhead
in terms of providing the allocation information to the user device
300. On the other hand, the flexibility and the adaptation
capability between using different number of PRB pairs or
modulation levels is lower. A higher-layer configured information
entity would be useful if the UCI information is not associated
with any downlink control channel, e.g., if it comprises only CSI
reports. Thereby, the user device 300 does not need to obtain the
uplink PUCCH resources by means of a downlink control channel,
which saves overhead in the downlink of the wireless communication
system 500.
[0107] In one embodiment of the present disclosure, the allocation
information is provided by a combination of higher-layer signalling
(e.g., MAC or RRC signalling) and physical layer signalling in the
downlink control channel. As an example, suppose that the
associated downlink control channel, e.g., PDCCH or EPDCCH,
comprises an indicator .DELTA..sub.i,i=0, 1, . . . , K-1, capable
of addressing K number of different states. This indicator
.DELTA..sub.i could be facilitated by signalling .left brkt-top.
log.sub.2(K).right brkt-bot. bits or utilizing unused states and
combinations of the existing bits in the downlink control channel.
For example, it could be sufficient that certain downlink control
information bits are not needed for PDCCH/EPDCCHs transmitted on
the secondary serving cells. Therefore, it could be possible to
utilize such bits from downlink control channels not being
associated with the downlink data transmission on the primary
serving cell for carrying the indicator .DELTA..sub.i. If these
bits are not sufficient, additional new bits could be inserted or
unused states and combinations of the existing bits in the downlink
control channel could be utilized.
[0108] For each of the mentioned K states, in one example, a
corresponding higher-layer information entity b.sub.i is
configured. This entity would convey information according to
number of allocated plurality of PRBs and frequency location of the
allocated plurality of PRBs. The higher-layer information entities
could be UE-specifically configured, which provides full
flexibility in efficiently allocating the resources, since
different UEs may be configured with different numbers of component
carriers and thereby require different UCI payload and consequently
have different need of PUCCH resources. Thus, a given state may
correspond to different number and/or positions of the PRBs for
different UEs. An advantage of utilizing a combination of physical
layer signalling and higher-layer configured entities b.sub.i is
that it allows dynamic switching between the number of PRB pairs
used for the transmission, which in beneficial for adapting the
resource utilization to the actual UCI payload, which can vary
significantly depending on the carrier aggregation configuration.
Thereby, the uplink control channel overhead can be reduced. It is
realized that if N PRB pairs can be allocated to the transmission,
there are .SIGMA..sub.k=1.sup.Nk=N(N+1)/2 unique combination of
contiguous PRB pairs of size 1 to N. In one further example, this
allocation information is provided by K=.left brkt-top. log.sub.2
(N(N+1)/2).right brkt-bot. bits associated with N(N+1)/2 bitmaps of
size N, where a `1` in the bitmap corresponds to an allocated PRB
pair. The definition of the bitmaps could either be predefined or
be configured by higher layers. Table 1 shows an example of
indicator .DELTA..sub.i.
[0109] Table 1 also gives an example of bitmaps
b.sub.i=[c.sub.0c.sub.1c.sub.2c.sub.3] for N=4, where c.sub.1
denotes an index to a PRB pair. The user device 300 could associate
a bitmap index c.sub.i to a PRB pair position (or PUCCH region) by
higher-layer configuration. For example, an offset value .delta.
could be configured such that the user device 300 determines the
PRB pair position as n=f(.DELTA..sub.i)+.delta., where .delta.
corresponds to the PRB pair position for c.sub.0.
TABLE-US-00001 TABLE 1 Example of resource allocation for PUCCH
.DELTA..sub.i [c.sub.0c.sub.1c.sub.2c.sub.3] R b.sub.i 0 [0001] 3 1
1 [0010] 2 2 2 [0100] 1 4 3 [1000] 0 8 4 [0011] 6 2, 1 5 [0110] 5
4, 2 6 [1100] 4 8, 4 7 [0111] 9 4, 2, 1 8 [1110] 8 8, 4, 2 9 [1111]
7 8, 4, 2, 1
[0110] The interpretation of the bitmap could also be so that
either: [0111] a bit `1` corresponds to a PRB index to be used in
both time slots; or [0112] a bit `1` corresponds to a PUCCH
region.
[0113] The first interpretation allows using the same PRB in both
time slots. The second interpretation allows using allocations by
means of PUCCH regions, while utilizing contiguous PRBs in a time
slot.
[0114] Another representation of a bitmap with only contiguous bit
combinations is to use an index R. Suppose that the N available PRB
pairs are enumerated from 0 to N-1 and that the allocation
comprises L PRB pairs with the first PRB pair starting at an index
S, then the single index R could encode all eligible allocations
according to:
If L - 1 .ltoreq. N 2 ##EQU00001## R = N ( L - 1 ) + S
##EQU00001.2## Else ##EQU00001.3## R = N ( N - L + 1 ) + ( N - 1 -
S ) . ##EQU00001.4##
[0115] As an example, this would give the indices of R listed in
Table 1. Thus, one realization of the embodiment is that
.DELTA..sub.i=R. The receiver could associate an index to a PRB
pair position (or PUCCH region) by higher-layer configuration. For
example, an offset value .delta. could be configured such that the
user device 300 determines the PRB pair position as
n=f(.DELTA..sub.i)+.delta., where .delta. corresponds to the PRB
pair position for a given index R. Also in this case, the
interpretation of the index could allow using the same PRB in both
time slots or allocations by means of PUCCH regions, while
utilizing contiguous PRBs in a time slot.
[0116] An advantage of this embodiment of the present disclosure is
a better reuse of the PUCCH resources. For example, it would be
possible to let some of the configured PRB pairs overlap with PRB
pairs allocated for other PUCCH formats. By using the dynamically
signalled parameter .DELTA..sub.i, collisions between PUCCH formats
could be avoided. For example, in Table 1, if index c.sub.0
corresponds to a PRB pair overlapping with another PUCCH format
which is occupied in the given subframe, the eNodeB could still
perform the resource allocation by not signalling
.DELTA..sub.i=3,6,8,9.
[0117] As to further reduce the number K and the amount of bits
needed to convey .DELTA..sub.i, it is possible to only allow a
subset of the contiguous allocations. For example, in Table 1, 4
bits would suffice if only states 3, 6, 8 and 9 are allowed. That
is, the four states correspond to a transmission on 1, 2, 3 or 4
PRB pairs, respectively.
[0118] In another embodiment of the present disclosure, in order to
reduce the number of states which need to be signalled, the
information entity .DELTA..sub.i corresponds the number of PRB
pairs to be used for the transmission and the PRB pair positions
are obtained by function n=f(.DELTA..sub.i)+.delta. where .delta.
is a higher layer configured offset value. For example,
f(.delta.)=.DELTA..sub.i+1 when .DELTA..sub.i=0, 1, . . . .
[0119] In another embodiment of the present disclosure, the
allocation information is provided by directly letting an entity
b.sub.i comprise indices to the PRB pairs (or PUCCH regions) used
for the transmission of the new PUCCH format, without utilizing any
bitmaps. This requires that one or several indices are associates
to each state of .DELTA..sub.i. This implies that different
.DELTA..sub.i will be associated with different numbers of indices.
An example of such a representation is also given in Table 1. These
indices may be higher-layer configured.
[0120] In one embodiment of the present disclosure, the information
entity .DELTA. is only provided by physical layer signalling. This
gives maximum freedom in allocating the PRB pairs but could require
slightly more overhead. For example, if the carrier bandwidth is M
resource blocks, .left brkt-top. log.sub.2 (M/(M+1)/2).right
brkt-bot. bits would be needed in the downlink control channel for
determining the number of and positions of the contiguous PRB pairs
to be used for transmission.
[0121] In one embodiment of the present disclosure, the allocated
PRB pairs are contiguous in frequency within a time slot but all
the available resources (from which the allocation is made) are not
necessarily contiguous. This is advantageous for example if the new
PUCCH format is used for CSI reporting. It may be favourable to
allocate a set of contiguous higher-layer configured PRB pairs
close to the carrier edge for this purpose. At the same time, it
could be beneficial to reserve a set of PRB pairs closer to the
centre of the carrier, in order to predominately carry the HARQ-ACK
information. Therefore, in a subframe wherein there is not supposed
to be any CSI reports, but HARQ-ACK information, it should be
possible to use the high-layer configured CSI reporting PRB pairs
for transmission of the PUCCH containing the HARQ-ACK
information.
[0122] An example in its most general form is contained in Table 2,
wherein each indicator .DELTA..sub.i is associated with one or
several higher-layer configured entities b.sub.i, each
corresponding to a PRB pair (or PUCCH region). For example, for
.DELTA..sub.i=4, the two entities b.sub.i=4 and b.sub.i=5 are
associated with two contiguous PRB pairs (or PUCCH regions), while
for .DELTA..sub.i=5, the two entities b.sub.i=6 and b.sub.i=7 are
associated with another two disjoint contiguous PRB pairs (or PUCCH
regions). Hence, suppose b.sub.i=6 and b.sub.i=7 are associated
with PRB pairs located close to the carrier edge, and that these
resources have also been configured by higher layers to accommodate
CSI reporting, then it would be possible to that also UCI in form
of HARQ-ACK could utilize these resources when .DELTA..sub.i=5 is
provided.
TABLE-US-00002 TABLE 2 Example of resource allocation for PUCCH
.DELTA..sub.i b.sub.i 0 0 1 1 2 2 3 3 4 4, 5 5 6, 7 6 8, 9 7 10,
11, 12 8 13, 14, 15 9 16, 17, 18, 19
[0123] The resource allocation provides a number of PRB pairs for
the UCI transmission, which relates to the code rate of the UCI
transmission, since it determines the number of coded bits. Thus,
for a fixed UCI payload, a larger number of allocated PRB pairs
lowers the code rate, which improves the detection performance of
the UCI. This may render that the downlink carrier aggregation can
be performed on a larger area in the cell, since the PUCCH can be
decoded at lower signal-to-noise ratios. It is further understood
that additional adjustment of the code rate is possible by the
disclosure by relating the number of UCI payload bits to the
allocated number of PUCCH resources. This may be achieved by
letting the index .DELTA..sub.i additionally be related to the
number of UCI payload bits according to some predefined rule. For
example, if the UE is only scheduled on a small number of its
configured downlink component carriers (say it is configured with X
number of component carriers), the value .DELTA..sub.i could
additionally inform the UE to only feedback HARQ-ACK information as
if it was configured with Z (where Z<X) downlink component
carriers. This may reduce the code rate since the number of
information bits is reduced, which may require even less allocated
number of PRB pairs, thereby saving overhead.
[0124] In one embodiment of the present disclosure, the information
entity .DELTA. further makes it possible to determine the
modulation order and/or modulation type to be used in the new PUCCH
format. This is advantageous since it allows more efficient control
of the uplink control channel resources. For example, if the user
device 300 is experiencing good channel conditions, it may employ
higher order modulation and utilize less PRB pairs for its uplink
control channel. This property can be combined with the
aforementioned embodiments concerning providing information for
number of allocated plurality of PRBs and frequency location of the
allocated plurality of PRBs.
[0125] In one embodiment of the present disclosure, the indication
of the modulation level and/or modulation type is provided by
physical layer signalling and is separately encoded from the
entities providing information about number of allocated plurality
of PRBs and frequency location of the allocated plurality of PRBs.
For example, an indication whether to use Quadrature Phase Shift
Keying (QPSK) or 16 Quadrature Amplitude Modulation (QAM), i.e.,
modulation types, could be enabled by a single bit in the downlink
control channel, or some unused state of the existing bits in the
downlink control channel.
[0126] In one example, the indication of the modulation level is
provided by physical layer signalling and is jointly encoded from
the network node 100 providing information about number of
allocated plurality of PRBs and frequency location of the allocated
plurality of PRBs. An advantage of this is that it could reduce the
number of bits needed to be transmitted in the downlink control
channel. It can be noted that in many cases .left brkt-top.
log.sub.2 (N (N+1)/2).right brkt-bot.>log.sub.2N(N+1)/2, thus
there may be bits unused for determining allocation information
about number of allocated plurality of PRBs and frequency location
of the allocated plurality of PRBs, which could be used for
determining information about modulation level and/or modulation
type. Table 3 shows one example of joint encoding utilizing in
total 4 bits.
TABLE-US-00003 TABLE 3 Example of 10 bitmaps of length 4 and
modulation type .DELTA..sub.i [c.sub.0c.sub.1c.sub.2c.sub.3]
Modulation 0 [0001] QPSK 1 [0010] QPSK 2 [0100] QPSK 3 [1000] QPSK
4 [0011] QPSK 5 [0110] QPSK 6 [1100] QPSK 7 [0111] QPSK 8 [1110]
QPSK 9 [1111] QPSK 10 [0001] 16 QAM 11 [0010] 16 QAM 12 [0100] 16
QAM 13 [1000] 16 QAM 14 [0011] 16 QAM 15 [0110] 16 QAM
[0127] Another example is to associate certain resource allocations
with certain modulation levels. Table 4 gives a non-limiting
example where information about number of allocated plurality of
PRBs and frequency location of the allocated plurality of PRBs and
modulation level and/or modulation type are jointly encoded. A
person skilled in the art may combine the indication of modulation
level and/or type with any of the previously embodiments for
indicating the PRB pair allocation for the new PUCCH format.
TABLE-US-00004 TABLE 4 Example of 10 bitmaps of length 4 and
modulation type .DELTA..sub.i [c.sub.0c.sub.1c.sub.2c.sub.3]
Modulation 0 [0001] QPSK 1 [0010] 16 QAM 2 [0100] QPSK 3 [1000] 16
QAM 4 [0011] QPSK 5 [0110] 16 QAM 6 [1100] QPSK 7 [0111] QPSK 8
[1110] QPSK 9 [1111] QPSK
[0128] Moreover, FIGS. 7-10 illustrate examples of time and
frequency allocation for PUCCH formats according to the present
solution in an exemplary LTE context. The examples are given for
time slots 0 and 1 (denoted as "slot" in FIGS. 7-10).
[0129] FIG. 7 shows a PUCCH resource reservation where a new
multi-PRB pair PUCCH format, here referred to as PUCCH format 4, is
located between the PUCCH format 3 and PUCCH format 1/1a/1b
resources. If there would be no need to transmit new PUCCH format 4
in a subframe, its resources would comprise unnecessary overhead
since the freed up resources are not located in the PUSCH region
and can therefore not be easily reused for PUSCH transmission. It
should be noted that new PUCCH format 4 is only and exemplary PUCCH
format of the present solution and is therefore not limited
thereof.
[0130] FIG. 8 shows another example of PUCCH resource reservation
where the PUCCH resources for the so called PUCCH format 4 is
located towards the centre of the carrier. If not all PUCCH format
1/1a/1b resources would be used, this would also comprise
additional overhead since the free PRB pairs (m=4, m=M-5) cannot
easily be used for PUSCH scheduling the PUSCH.
[0131] FIG. 9 shows an example where a set of higher layer PRB
pairs (PUCCH regions 6-11) are allocated to the new PUCCH format 4
while at the same time PUCCH regions 2-11 are allocated to PUCCH
formats 1/1a/1b. Thus, although these PUCCH formats cannot be
transmitted in the same PRB pairs simultaneously, the PUCCH
resources are configured to overlap, i.e., occupy the same PUCCH
resources as for another PUCCH format. Thus, if in a given
subframe, only PUCCH regions 2-5 are needed for PUCCH formats
1/1a/1b, PUCCH regions 6-11 could be used for the new PUCCH format
4. This allows maximum reuse of the control channel resources.
Similarly, if PUCCH format 1/1a/1b need to utilize PUCCH regions 6
and 7, new PUCCH format 4 could still be used in PUCCH regions
8-12, and so on.
[0132] FIG. 10 shows another example of overlapping where it is
assumed that new PUCCH format 4 could be multiplexed on the same
PRB pair used for PUCCH format 3 transmissions. PUCCH format 3
resources are allocated to PUCCH regions 2-5, while new PUCCH
format 4 resources are allocated to PUCCH regions 2-11, which
partially overlaps with the PUCCH format 1/1a/1b resources in PUCCH
regions 6-11. Thus, when the eNodeB could assure that it does not
need to utilize some or all PUCCH format 1/1a/1b resources in PUCCH
regions 6-11, these PRB pairs could be released and used for new
PUCCH format 4. Hence, a larger frequency reuse is obtained and
more resources are released for the uplink data channel PUSCH.
[0133] Furthermore, any method according to the present disclosure
may be implemented in a computer program, having code means, which
when run by processing means causes the processing means to execute
the steps of the method. The computer program is included in a
computer readable medium of a computer program product. The
computer readable medium may comprises of essentially any memory,
such as a ROM (Read-Only Memory), a PROM (Programmable Read-Only
Memory), an EPROM (Erasable PROM), a Flash memory, an EEPROM
(Electrically Erasable PROM), or a hard disk drive.
[0134] Moreover, it is realized by the skilled person that the
present first network node and second network node comprises the
necessary communication capabilities in the form of e.g.,
functions, means, units, elements, etc., for performing the present
solution. Examples of other such means, units, elements and
functions are: processors, memory, buffers, control logic,
encoders, decoders, rate matchers, de-rate matchers, mapping units,
multipliers, decision units, selecting units, switches,
interleavers, de-interleavers, modulators, demodulators, inputs,
outputs, antennas, amplifiers, receiver units, transmitter units,
DSPs, MSDs, TCM encoder, TCM decoder, power supply units, power
feeders, communication interfaces, communication protocols, etc.
which are suitably arranged together for performing the present
solution.
[0135] Especially, the processors of the present devices may
comprise, e.g., one or more instances of a Central Processing Unit
(CPU), a processing unit, a processing circuit, a processor, an
Application Specific Integrated Circuit (ASIC), a microprocessor,
or other processing logic that may interpret and execute
instructions. The expression "processor" may thus represent a
processing circuitry comprising a plurality of processing circuits,
such as, e.g., any, some or all of the ones mentioned above. The
processing circuitry may further perform data processing functions
for inputting, outputting, and processing of data comprising data
buffering and device control functions, such as call processing
control, user interface control, or the like.
[0136] Finally, it should be understood that the present disclosure
is not limited to the embodiments described above, but also relates
to and incorporates all embodiments within the scope of the
appended independent claims.
* * * * *