U.S. patent application number 17/746371 was filed with the patent office on 2022-09-01 for node and method for downlink scheduling and hybrid automatic repeat request timing.
The applicant listed for this patent is Telefonaktiebolaget LM Ericsson (Publ). Invention is credited to Daniel CHEN LARSSON, Jung-Fu CHENG.
Application Number | 20220279567 17/746371 |
Document ID | / |
Family ID | 1000006333194 |
Filed Date | 2022-09-01 |
United States Patent
Application |
20220279567 |
Kind Code |
A1 |
CHEN LARSSON; Daniel ; et
al. |
September 1, 2022 |
NODE AND METHOD FOR DOWNLINK SCHEDULING AND HYBRID AUTOMATIC REPEAT
REQUEST TIMING
Abstract
Some of the example embodiments are directed towards a base
station for determining a control timing configuration in order to
provide a subframe timing setting for configuring downlink HARQ-ACK
control timing for a cell serving a user equipment in a multiple
cell communications network. The user equipment is served by a TDD
based cell and a FDD based cell. Some example embodiments are
directed towards user equipment for determining the control timing
configuration as discussed above.
Inventors: |
CHEN LARSSON; Daniel;
(Vallentuna, SE) ; CHENG; Jung-Fu; (Fremont,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Telefonaktiebolaget LM Ericsson (Publ) |
Stockholm |
|
SE |
|
|
Family ID: |
1000006333194 |
Appl. No.: |
17/746371 |
Filed: |
May 17, 2022 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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17012264 |
Sep 4, 2020 |
11368976 |
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17746371 |
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16173224 |
Oct 29, 2018 |
10813121 |
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17012264 |
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15061510 |
Mar 4, 2016 |
10165593 |
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16173224 |
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14239454 |
Feb 18, 2014 |
9319211 |
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PCT/SE2013/051209 |
Oct 16, 2013 |
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15061510 |
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61869084 |
Aug 23, 2013 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04L 1/1893 20130101;
H04W 72/0446 20130101; H04L 1/1812 20130101; H04L 5/0055 20130101;
H04W 72/1289 20130101; H04L 5/14 20130101 |
International
Class: |
H04W 72/12 20060101
H04W072/12; H04L 1/18 20060101 H04L001/18; H04L 5/00 20060101
H04L005/00; H04L 5/14 20060101 H04L005/14; H04W 72/04 20060101
H04W072/04 |
Claims
1. A method, in a user equipment, for determining a control timing
configuration, the control timing configuration providing a
subframe timing setting for configuring downlink Hybrid Automatic
Retransmission Request Acknowledgment (HARQ-ACK) control timing for
a cell serving the user equipment in a multiple cell communications
network, the user equipment being served by a Time Division Duplex
(TDD) based cell, and a Frequency Division Duplex (FDD) based cell,
the method comprising: determining a control timing configuration
for a secondary cell, the secondary cell being the FDD based cell,
based on a control timing configuration of a primary cell, the
primary cell being the TDD based cell; and implementing the control
timing configuration for downlink HARQ-ACK control timing for the
secondary cell serving the user equipment.
2. The method of claim 1, wherein the determining further
comprising determining the control timing configuration comprises a
HARQ-ACK feedback timing value of 4 for all subframes.
3. The method of claim 1, wherein the the determining further
comprising determining the control timing configuration to be
equivalent to a TDD configuration of the primary cell.
4. The method of claim 1, wherein the determining further
comprising determining the control timing configuration to be one
of: configuration number 2 if the configuration number of the
primary cell is one of 0, 1, 2 and 6; and configuration 5 if the
configuration number of the primary cell is one of 3, 4 and 5.
5. The method of claim 1, wherein the determining further
comprising determining the control timing configuration based on a
first altered configuration table, wherein the first altered
configuration table is: TABLE-US-00012 UL-DL Configu- Subframe n
ration 0 1 2 3 4 5 6 7 8 9 2* 8, 7, 4, 8, 7, 6, 5 4, 6, 5 3* 7, 6,
11, 6, 5 5, 4 10, 9, 8 4* 12, 8, 7, 6, 5, 11, 10, 9 4, 7 5* 13, 12,
9, 8, 7, 5, 4, 11, 6, 10
and wherein "UL" refers to uplink and "DL" refers to downlink.
6. The method of claim 5, wherein the determining further comprises
determining the control timing configuration to be one of: 2* if
the control timing configuration of the primary cell is one of 0,
1, 2 and 6; and 5* if the control timing configuration of the
primary cell is one of 3, 4 and 5.
7. The method of claim 5, wherein the determining further comprises
determining the control timing configuration to be one of: 2* if
the control timing configuration of the primary cell is one of 0,
1, 2 and 6; and N* if the control timing configuration of the
primary cell is N, wherein N is an integer with a value of 3-5.
8. The method of claim 1, the determining further comprising
determining the control timing configuration based on a second
altered configuration table, wherein the second altered
configuration table is: TABLE-US-00013 UL-DL Configu- Subframe n
ration 0 1 2 3 4 5 6 7 8 9 1* 7, 6,5, 4 7, 6, 4 4 5, 4 2* 8, 7, 4,
8, 7, 6, 5 4, 6, 5 3* 7, 6, 11, 6, 5 5, 4 10, 9, 8 4* 12, 8, 7, 6,
5, 11, 10, 9 4, 7 5* 13, 12, 9, 8, 7, 5, 4, 11, 6, 10
wherein the control timing configuration is one of: 1* if the
control timing configuration of the primary cell is one of 0, 1,
and 6; and N* if the control timing configuration of the primary
cell is N, wherein N is an integer with a value of 2-5; and wherein
"UL" refers to uplink and "DL" refers to downlink.
9. The method of claim 1, wherein the determining further
comprising determining the control timing configuration based on a
third altered configuration table, wherein the third altered
configuration table is: TABLE-US-00014 UL-DL Configu- Subframe n
ration 0 1 2 3 4 5 6 7 8 9 0* 6, 5, 4, 5 6, 5, 4, 5 4 4 1* 7, 6, 4
7, 6, 4 5, 4 5, 4 2* 8, 7, 8, 7, 4, 6, 4, 6, 5 5 3* 7, 6, 6, 5 5, 4
11, 10, 9, 8 4* 12, 8, 6, 5, 7, 11, 4, 7 10, 9 5* 13, 12, 9, 8, 7,
5, 4, 11, 6, 10 6* 7 7, 6, 5 7, 6, 7 5 5, 4
wherein the control timing configuration is N* if the control
timing configuration of the primary cell is N, wherein N is an
integer with a value of 0-6; and wherein "UL" refers to uplink and
"DL" refers to downlink.
10. A user equipment for determining a control timing
configuration, the control timing configuration providing a
subframe timing setting for configuring downlink Hybrid Automatic
Retransmission Request Acknowledgment (HARQ-ACK) control timing for
a cell serving the user equipment in a multiple cell communications
network, the user equipment being served by a Time Division Duplex
(TDD) based cell, and a Frequency Division Duplex (FDD) based cell,
the user equipment comprising: processing circuitry configured to
determine a control timing configuration for a secondary cell, the
secondary cell being the FDD based cell, based on a control timing
configuration of a primary cell, the primary cell being the TDD
based cell; and the processing circuitry further configured to
implement the control timing configuration for downlink HARQ-ACK
control timing for the secondary cell serving the user
equipment.
11. The user equipment of claim 10, wherein the processing
circuitry further configured to determine the control timing
configuration comprises a HARQ-ACK feedback timing value of 4 for
all subframes.
12. The user equipment of claim 10, wherein the processing
circuitry is further configured to determine the control timing
configuration to be equivalent to a TDD configuration of the
primary cell.
13. The user equipment of claim 10, wherein the processing
circuitry is further configured to determine the control timing
configuration to be one of: configuration number 2 if the
configuration number of the primary cell is one of 0, 1, 2 and 6;
and configuration 5 if the configuration number of the primary cell
is one of 3, 4 and 5.
14. The user equipment of claim 10, wherein the processing
circuitry is further configured to determine the control timing
configuration based on a first altered configuration table, wherein
the first altered configuration table is: TABLE-US-00015 UL-DL
Configu- Subframe n ration 0 1 2 3 4 5 6 7 8 9 2* 8, 7, 4, 8, 7, 6,
5 4, 6, 5 3* 7, 6, 11, 6, 5 5, 4 10, 9, 8 4* 12, 8, 7, 6, 5, 11,
10, 9 4, 7 5* 13, 12, 9, 8, 7, 5, 4, 11, 6, 10
and wherein "UL" refers to uplink and "DL" refers to downlink.
15. The user equipment of claim 14, wherein the processing
circuitry is further configured to determine the control timing
configuration to be one of: 2* if the control timing configuration
of the primary cell is one of 0, 1, 2 and 6; 5* if the control
timing configuration of the primary cell is 3, 4 and 5.
16. The user equipment of claim 14, wherein the processing
circuitry is further configured to determine the control timing
configuration to be one of: 2* if the control timing configuration
of the primary cell is one of 0, 1, 2 and 6; and N* if the control
timing configuration of the primary cell is N, wherein N is an
integer with a value of 3-5.
17. The user equipment of claim 10, wherein the processing
circuitry is further configured to determine the control timing
configuration based on a second altered configuration table,
wherein the second altered configuration table is: TABLE-US-00016
UL-DL Configu- Subframe n ration 0 1 2 3 4 5 6 7 8 9 1* 7, 6, 5, 4
7, 6, 4 4 5, 4 2* 8, 7, 4, 8, 7, 6, 5 4, 6, 5 3* 7, 6, 11, 6, 5 5,
4 10, 9, 8 4* 12, 8, 7, 6, 5, 11, 10, 9 4, 7 5* 13, 12, 9, 8, 7, 5,
4, 11, 6, 10
wherein the control timing configuration is one of: 1* if the
control timing configuration of the primary cell is one of 0, 1,
and 6; and N* if the control timing configuration of the primary
cell is N, wherein N is an integer with a value of 2-5; and wherein
"UL" refers to uplink and "DL" refers to downlink.
18. The user equipment of claim 10, wherein the processing
circuitry is further configured to determine the control timing
configuration based on a third altered configuration table, wherein
the third altered configuration table is: TABLE-US-00017 UL-DL
Configu- Subframe n ration 0 1 2 3 4 5 6 7 8 9 0* 6, 5, 4, 5 6, 5,
4, 5 4 4 1* 7, 6, 4 7, 6, 4 5, 4 5, 4 2* 8, 7, 8, 7, 4, 6, 4, 6, 5
5 3* 7, 6, 6, 5 5, 4 11, 10, 9, 8 4* 12, 8, 6, 5, 7, 11, 4, 7 10, 9
5* 13, 12, 9, 8, 7, 5, 4, 11, 6, 10 6* 7 7, 6, 5 7, 6, 7 5 5, 4
wherein the control timing configuration is N* if the control
timing configuration of the primary cell is N, wherein N is an
integer with a value of 0-6; and wherein "UL" refers to uplink and
"DL" refers to downlink.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation of U.S. patent
application Ser. No. 17/012,264, filed Sep. 4, 2020, entitled "A
NODE AND METHOD FOR DOWNLINK SCHEDULING AND HYBRID AUTOMATIC REPEAT
REQUEST TIMING", which is a continuation of U.S. patent application
Ser. No. 16/173,224, filed Oct. 29, 2018, entitled "A NODE AND
METHOD FOR DOWNLINK SCHEDULING AND HYBRID AUTOMATIC REPEAT REQUEST
TIMING", now U.S. Pat. No. 10,813,121, which is a continuation of
U.S. patent application Ser. No. 15/061,510, filed Mar. 4, 2016,
entitled "A NODE AND METHOD FOR DOWNLINK SCHEDULING AND HYBRID
AUTOMATIC REPEAT REQUEST TIMING", now U.S. Pat. No. 10,165,593,
that is a continuation of a U.S. National Stage Patent application
Ser. No. 14/239,454, filed Feb. 18, 2014, entitled "NODE AND METHOD
FOR DOWNLINK SCHEDULING AND HYBRID AUTOMATIC REPEAT REQUEST
TIMING", now U.S. Pat. No. 9,319,211, which claims priority to
International Application Serial No. PCT/SE2013/051209,
International filing date Oct. 16, 2013, which claims the benefit
of U.S. Provisional Application Ser. No. 61/869,084, filed Aug. 23,
2013, the entirety of each of which is incorporated herein by
reference.
TECHNICAL FIELD
[0002] Some of the example embodiments presented herein are
directed towards a base station and user equipment, as well as
corresponding methods therein, for determining a control timing
configuration to provide a subframe timing setting for configuring
downlink HARQ-ACK control timing for a cell serving the user
equipment in a multiple cell communications network.
BACKGROUND
[0003] Long Term Evolution Systems
[0004] Long Term Evolution (LTE) uses Orthogonal Frequency Division
Multiplexing (OFDM) in the downlink direction and a Discrete
Fourier Transform (DFT)-spread OFDM in the uplink direction. The
basic LTE downlink physical resource can thus be seen as a
time-frequency grid, where each resource element corresponds to one
OFDM subcarrier during one OFDM symbol interval. In the time
domain, LTE downlink transmissions may be organized into radio
frames of 10 ms, with each radio frame consisting of ten
equally-sized subframes of length Tsubframe=1 ms.
[0005] Furthermore, the resource allocation in LTE is typically
described in terms of resource blocks, where a resource block
corresponds to one slot, e.g., 0.5 ms, in the time domain and 12
subcarriers in the frequency domain. A pair of two adjacent
resource blocks in time direction, e.g., 1.0 ms, is known as a
resource block pair. Resource blocks are numbered in the frequency
domain, starting with 0 from one end of the system bandwidth.
[0006] The notion of virtual resource blocks (VRB) and physical
resource blocks (PRB) has been introduced in LTE. The actual
resource allocation to a user equipment is made in terms of VRB
pairs. There are two types of resource allocations, localized and
distributed. In the localized resource allocation, a VRB pair is
directly mapped to a PRB pair, hence two consecutive and localized
VRBs are also placed as consecutive PRBs in the frequency domain.
On the other hand, the distributed VRBs are not mapped to
consecutive PRBs in the frequency domain, thereby providing
frequency diversity for data channel transmitted using these
distributed VRBs.
[0007] Downlink transmissions are dynamically scheduled, i.e., in
each subframe the base station transmits control information
regarding which terminals data is transmitted and upon which
resource blocks the data is transmitted, in the current downlink
subframe. This control signaling is typically transmitted in the
first 1, 2, 3 or 4 OFDM symbols in each subframe and the number
n=1, 2, 3 or 4 is known as the Control Format Indicator (CFI). The
downlink subframe also contains common reference symbols, which are
known to the receiver and used for coherent demodulation of, e.g.,
the control information.
[0008] From LTE Release 11 and onwards, the above described
resource assignments may also be scheduled on the enhanced Physical
Downlink Control Channel (EPDCCH). For 3GPP Release 8 to 3GPP
Release 10, only Physical Downlink Control Channel (PDCCH) is
available.
[0009] PDCCH
[0010] The PDCCH is used to carry downlink control information
(DCI) such as scheduling decisions and power-control commands. More
specifically, the DCI comprises downlink scheduling assignments,
including PDSCH resource indication, transport format, hybrid-ARQ
information, and control information related to spatial
multiplexing, if applicable. A downlink scheduling assignment also
includes a command for power control of the PUCCH used for
transmission of hybrid-ARQ acknowledgements in response to downlink
scheduling assignments.
[0011] The DCI further comprises uplink scheduling grants,
including PUSCH resource indication, transport format, and
hybrid-ARQ-related information. An uplink scheduling grant also
includes a command for power control of the PUSCH. The DCI further
comprises power-control commands for a set of terminals as a
complement to the commands included in the scheduling
assignments/grants.
[0012] One PDCCH carries one DCI message with one of the formats
above. As multiple terminals may be scheduled simultaneously, on
both downlink and uplink, there must be a possibility to transmit
multiple scheduling messages within each subframe. Each scheduling
message is transmitted on a separate PDCCH, and consequently there
are typically multiple and simultaneous PDCCH transmissions within
each cell. Furthermore, to support different radio-channel
conditions, link adaptation may be used, where the code rate of the
PDCCH is selected to match the radio-channel conditions.
[0013] To allow for simple yet efficient processing of the control
channels in the terminal, the mapping of PDCCHs to resource
elements is subject to a certain structure. This structure is based
on Control-Channel Elements (CCEs), which consists of nine REGs.
The number of CCEs, one, two, four, or eight, required for a
certain PDCCH depends on the payload size of the control
information (DCI payload) and the channel-coding rate. This is used
to realize link adaptation for the PDCCH; if the channel conditions
for the terminal to which the PDCCH is intended are
disadvantageous, a larger number of CCEs is used compared to the
case of advantageous channel conditions. The number of CCEs used
for a PDCCH is also referred to as the aggregation level (AL).
[0014] The network may then select different aggregation levels and
PDCCH positions for different user equipments from the available
PDCCH resources. For each PDCCH, a CRC is attached to each DCI
message payload. The identity of the terminal (or terminals)
addressed, e.g., the RNTI, is provided in the CRC calculation and
not explicitly transmitted. Depending on the purpose of the DCI
message, for example, unicast data transmission, power-control
command, random-access response, etc., different RNTIs are used.
For normal unicast data transmission, the terminal-specific C-RNTI
is used.
[0015] After CRC attachment, the bits are coded with a rate-1/3
tail-biting convolutional code and rate matched to fit the amount
of resources used for PDCCH transmission. After the PDCCHs to be
transmitted in a given subframe have been allocated to the desired
resource elements, the sequence of bits corresponding to all the
PDCCH resource elements to be transmitted in the subframe,
including the unused resource elements, is scrambled by a cell and
subframe specific scrambling sequence to randomize inter-cell
interference. Such scrambling is followed by QPSK modulation and
mapping to resource elements. The entire collection of the REGs,
including those unused by any PDCCH, is then interleaved across
entire control region to randomize inter-cell interference as well
as capturing frequency diversity for the PDCCHs.
[0016] PUCCH
[0017] If the mobile terminal has not been assigned an uplink
resource for data transmission, the L1/L2 control information,
e.g., channel-status reports, hybrid-ARQ acknowledgments, and
scheduling requests, is transmitted in uplink resources, e.g.,
resource blocks, specifically assigned for uplink L1/L2 control on
3GPP Release 8 PUCCH. These resources are located at the edges of
the total available cell bandwidth. Each such resource consists of
12 "subcarriers", e.g., one resource block, within each of the two
slots of an uplink subframe. In order to provide frequency
diversity, these frequency resources are frequency hopping on the
slot boundary, i.e., one "resource" consists of 12 subcarriers at
the upper part of the spectrum within the first slot of a subframe
and an equally sized resource at the lower part of the spectrum
during the second slot of the subframe or vice versa. If more
resources are needed for the uplink L1/L2 control signaling, e.g.,
in case of very large overall transmission bandwidth supporting a
large number of users, additional resources blocks can be assigned
next to the previously assigned resource blocks.
[0018] Carrier Aggregation
[0019] The LTE Release 10 standard has recently been standardized,
supporting bandwidths larger than 20 MHz. One important requirement
on LTE Release 10 is to assure backward compatibility with LTE
Release 8. This should also include spectrum compatibility. That
would imply that an LTE Release 10 carrier, wider than 20 MHz,
should appear as a number of LTE carriers to an LTE Release 8
terminal. Each such carrier may be referred to as a Component
Carrier (CC). In particular for early LTE Release 10 deployments it
may be expected that there will be a smaller number of LTE Release
10 capable terminals compared to many LTE legacy terminals.
Therefore, it is necessary to assure an efficient use of a wide
carrier also for legacy terminals, i.e., that it is possible to
implement carriers where legacy terminals may be scheduled in all
parts of the wideband LTE Release 10 carrier. The straightforward
way to obtain this would be by means of Carrier Aggregation (CA).
CA implies that an LTE Release 10 terminal may receive multiple CC,
where the CC have, or at least the possibility to have, the same
structure as a Release 8 carrier.
[0020] The number of aggregated CC as well as the bandwidth of the
individual CC may be different for uplink and downlink. A symmetric
configuration refers to the case where the number of CCs in
downlink and uplink is the same whereas an asymmetric configuration
refers to the case that the number of CCs is different. It is
important to note that the number of CCs configured in a cell may
be different from the number of CCs seen by a terminal: A terminal
may for example support more downlink CCs than uplink CCs, even
though the cell is configured with the same number of uplink and
downlink CCs.
[0021] During initial access a LTE Release 10 terminal behaves
similar to a LTE Release 8 terminal. Upon successful connection to
the network a terminal may, depending on its own capabilities and
the network, be configured with additional CCs in the UL and DL.
Configuration is based on RRC. Due to the heavy signaling and
rather slow speed of RRC signaling, it is envisioned that a
terminal may be configured with multiple CCs even though not all of
them are currently used. If a terminal is configured on multiple
CCs this would imply it has to monitor all DL CCs for PDCCH and
PDSCH. This implies a wider receiver bandwidth, higher sampling
rates, etc., resulting in high power consumption.
[0022] To mitigate the above problems, LTE Release 10 supports
activation of CCs on top of configuration. The terminal monitors
only configured and activated CCs for PDCCH and PDSCH. Since
activation is based on Medium Access Control (MAC) control
elements, which are faster than RRC signaling,
activation/de-activation may follow the number of CCs that are
required to fulfill the current data rate needs. Upon arrival of
large data amounts multiple CCs are activated, used for data
transmission, and de-activated if not needed anymore. All but one
CC, the DL Primary CC (DL PCC), may be de-activated. Activation
provides therefore the possibility to configure multiple CC but
only activate them on a need basis. Most of the time a terminal
would have one or very few CCs activated resulting in a lower
reception bandwidth and thus battery consumption.
[0023] Scheduling of a CC is done on the PDCCH via downlink
assignments. Control information on the PDCCH is formatted as a
Downlink Control Information (DCI) message. In Release 8 a terminal
only operates with one DL and one UL CC, the association between DL
assignment, UL grants and the corresponding DL and UL CCs is
therefore clear. In LTE Release 10 two modes of CA needs to be
distinguished. The first case is very similar to the operation of
multiple Release 8 terminals, a DL assignment or UL grant contained
in a DCI message transmitted on a CC is either valid for the DL CC
itself or for associated (either via cell-specific or UE specific
linking) UL CC. A second mode of operation augments a DCI message
with the Carrier Indicator Field (CIF). A DCI containing a DL
assignment with CIF is valid for that DL CC indicted with CIF and a
DCI containing an UL grant with CIF is valid for the indicated UL
CC.
[0024] DCI messages for downlink assignments contain among others
resource block assignment, modulation and coding scheme related
parameters, HARQ redundancy version, etc. In addition to those
parameters that relate to the actual downlink transmission most DCI
formats for downlink assignments also contain a bit field for
Transmit Power Control (TPC) commands. These TPC commands are used
to control the uplink power control behavior of the corresponding
PUCCH that is used to transmit the HARQ feedback.
[0025] In LTE Release 10, the transmission of PUCCH is mapped onto
one specific uplink CC, the UL Primary CC (UL PCC). Terminals only
configured with a single DL CC, which is then the DL PCC, and UL
CC, which is then the UL PCC, are operating dynamic ACK/NACK on
PUCCH according to 3GPP Release 8. The first Control Channel
Element (CCE) used to transmit PDCCH for the DL assignment
determines the dynamic ACK/NACK resource on 3GPP Release 8 PUCCH.
Since only one DL CC is cell-specifically linked with the UL PCC no
PUCCH collisions may occur since all PDCCH are transmitted using
different first CCE.
[0026] Upon reception of DL assignments on a single Secondary CC
(SCC) or reception of multiple DL assignments, a PUCCH format
(which is referred to as CA PUCCH herein) that can carry the
HARQ-ACK of multiple serving cells should be used. A DL SCC
assignment alone is untypical. The eNB scheduler should strive to
schedule a single DL CC assignment on the DL PCC and try to
de-activate SCCs if not needed. A possible scenario that may occur
is that eNB schedules terminal on multiple DL CCs including the
PCC. If the terminal misses all but the DL PCC assignment it will
use Release 8 PUCCH instead of CA PUCCH. To detect this error case
eNB has to monitor both the Release 8 PUCCH and the CA PUCCH.
[0027] In LTE Release 10, the CA PUCCH format is based on the
number of configured CC. Configuration of CC is based on RRC
signaling. After successful reception/application of the new
configuration a confirmation message is sent back making RRC
signaling very safe.
[0028] CA PUCCH Transmission Scheme
[0029] In this application, CA PUCCH refers to means of
transmitting HARQ-ACK of multiple serving cells in the UL. For
Rel-10 LTE, CA PUCCH can be embodied in one of the following two
approaches. The first method is based on the use of PUCCH format 3
that is based on DFTS-OFDM. The multiple ACK/NACK bits are encoded
to form 48 coded bits. The coded bits are then scrambled with
cell-specific (and possibly DFTS-OFDM symbol dependent) sequences.
24 bits are transmitted within the first slot and the other 24 bits
are transmitted within the second slot. The 24 bits per slot are
converted into 12 QPSK symbols, DFT precoded, spread across five
DFTS-OFDM symbols and transmitted within one resource blocks
(bandwidth) and five DFTS-OFDM symbols (time). The spreading
sequence is user equipment specific and enables multiplexing of up
to five users within the same resource blocks. For the reference
signals cyclic shifted CAZAC sequences, e.g., computer optimized
sequences, may be used.
[0030] The second CA PUCCH method is called channel selection. The
basic principle is that the user equipment is assigned a set of
PUCCH format 1a/1b resources. The user equipment then selects one
of resources according to the ACK/NACK sequence the user equipment
should transmit. On one of the assigned resources, the user
equipment would then transmit a QPSK or BPSK. The eNB detects which
resource the user equipment used and which QPSK or BPSK value the
user equipment fed back on the used resource and combines this into
a HARQ response for associated DL cells. A similar type of mapping
including a bundling approach is also done for TDD as in the FDD,
in case the user equipment is configured with channel
selection.
[0031] Time Division Duplex
[0032] Transmission and reception from a node, e.g., a terminal or
user equipment 501 and base station 401 in a cellular system such
as LTE, may be multiplexed in the frequency domain or in the time
domain (or combinations thereof). Frequency Division Duplex (FDD)
as illustrated to the left in FIG. 1 implies that downlink and
uplink transmission take place in different, sufficiently
separated, frequency bands. Time Division Duplex (TDD), as
illustrated to the right in FIG. 1, implies that downlink and
uplink transmission take place in different, non-overlapping time
slots. Thus, TDD can operate in unpaired spectrum, whereas FDD
requires paired spectrum.
[0033] Typically, the structure of the transmitted signal in a
communication system is organized in the form of a frame structure.
For example, LTE uses ten equally-sized subframes of length 1 ms
per radio frame as illustrated in FIG. 2.
[0034] In case of FDD operation, illustrated in the upper section
of FIG. 2, there are two carrier frequencies, one for uplink
transmission (fUL) and one for downlink transmission (fDL). At
least with respect to the terminal in a cellular communication
system, FDD may be either full duplex or half duplex. In the full
duplex case, a terminal may transmit and receive simultaneously,
while in half-duplex operation, the terminal may not transmit and
receive simultaneously. The base station is capable of simultaneous
reception/transmission though, e.g., receiving from one terminal
while simultaneously transmitting to another terminal. In LTE, a
half-duplex terminal is monitoring/receiving in the downlink except
when explicitly being instructed to transmit in a certain
subframe.
[0035] In case of TDD operation, illustrated in the lower section
of FIG. 2, there is only a single carrier frequency and uplink and
downlink transmissions are always separated in time also on a cell
basis. As the same carrier frequency is used for uplink and
downlink transmission, both the base station and the mobile
terminals need to switch from transmission to reception and vice
versa. An essential aspect of any TDD system is to provide the
possibility for a sufficiently large guard time where neither
downlink nor uplink transmissions occur. This is required to avoid
interference between uplink and downlink transmissions. For LTE,
this guard time is provided by special subframes, e.g., subframe 1
and, in some cases, subframe 6, which are split into three parts: a
downlink part (DwPTS), a guard period (GP), and an uplink part
(UpPTS). The remaining subframes are either allocated to uplink or
downlink transmission.
[0036] TDD allows for different asymmetries in terms of the amount
of resources allocated for uplink and downlink transmission,
respectively, by means of different downlink/uplink configurations.
In LTE, there are seven different configurations as shown in FIG.
3. It should be appreciated that a DL subframe may mean either DL
or the special subframe.
[0037] To avoid severe interference between downlink and uplink
transmissions between different cells, neighbor cells should have
the same downlink/uplink configuration. If this is not done, uplink
transmission in one cell may interfere with downlink transmission
in the neighboring cell and vice versa. Hence, the downlink/uplink
asymmetry may typically not vary between cells, but is signaled as
part of the system information and remains fixed for a long period
of time.
[0038] TDD HARQ control timing
[0039] The timings for HARQ A/N feedbacks for the PDSCH are
specified with extensive tables and procedure descriptions for each
U/D configuration in Table 1. The user equipment shall also
feedback PDSCH decoding A/N information in pre-defined UL
subframes. The user equipment shall transmit such HARQ A/N
responses on the PUCCH in UL subframe n if there is PDSCH
transmission indicated by the detection of corresponding PDCCH or
there is PDCCH indicating downlink SPS release within subframe(s)
n-k, where k is within the association set K={k.sub.0,k.sub.1, . .
. , k.sub.m-1} listed in Table 1.
TABLE-US-00001 TABLE 1 Downlink association set index K = {k.sub.0,
k.sub.1, . . . , k.sub.M-1} for TDD UL-DL Configu- Subframe n
ration 0 1 2 3 4 5 6 7 8 9 0 6 4 6 4 1 7, 6 4 7, 6 4 2 8, 7, 4, 8,
7, 6 4, 6 3 7, 6, 11 6, 5 5, 4 4 12, 8, 7, 6, 5, 11 4, 7 5 13, 12,
9, 8, 7, 5, 4, 11, 6 6 7 7 5 7 7
[0040] Examples to illustrate the timing are in reference to FIG.
4A. It should be appreciated that the leftmost subframe is denoted
as subframe 0 and the rightmost subframe is denoted as subframe 9.
The subframe numbers have been provided in FIG. 4A for the purpose
of explanation. For the UL subframe 7 in the configuration 1 cell,
Table 1 shows K={7,6}, which corresponds to carrying possible HARQ
A/N feedbacks for PDSCHs transmitted in subframes 7-7=0 and 7-6=1
(n-k). This is illustrated as arrows originating from DL subframes
0 and 1, being directed towards the UL subframe 7 in FIG. 4A,
Configuration #1.
[0041] Similarly, for the UL subframe 2 in the configuration 2
cell, as illustrated in FIG. 4B, Table 1 shows K={8,7,4,6}, which
corresponding to carrying possible HARQ A/N feedbacks for PDSCHs
transmitted in subframes 4, 5, 6, and 8 of the preceding frame.
This is illustrated as arrows originating from these DL subframes
are directed towards the UL subframe 2 in FIG. 4B, Configuration
#2. It should be appreciated that in the examples provided herein,
the n-k calculation is a modular 10 calculation.
SUMMARY
[0042] In current 3GPP standards, the possibility of a user
equipment being served by an aggregated FDD and TDD carrier
simultaneously is not discussed or addressed. Thus, at least one
example object of the example embodiments presented herein is to
provide mechanisms to implement downlink scheduling and HARQ
control timing for a FDD and TDD carrier aggregated network.
[0043] Therefore, some of the example embodiments presented herein
are directed towards how to allocate the HARQ timing and scheduling
timing for PDSCH transmission, for example, DL HARQ. According to
some of the example embodiments, depending on which if either FDD
or a certain UL/DL configuration for TDD is used, an applicable
reference configuration is selected for the HARQ timing. An
advantage of the example embodiments is the ability to provide a
simple scheme to derive the subframes for the timing of HARQ and
scheduling for TDD and FDD aggregation.
[0044] Accordingly, some of the example embodiments are directed
towards a method, in a base station, for determining a control
timing configuration. The control timing configuration provides a
subframe timing setting for configuring downlink HARQ-ACK control
timing for a cell serving a user equipment in a multiple cell
communications network. The user equipment is served by a TDD based
cell and a FDD based cell.
[0045] The method comprises determining a control timing
configuration for a secondary cell. The secondary cell is one of
the TDD based cell or the FDD based cell. The determining of the
control timing configuration is based on a control timing
configuration of a primary cell. The primary cell is one of the FDD
based cell or the TDD based cell, respectively. The method further
comprises implementing the control timing configuration for
downlink HARQ-ACK control timing for a cell serving the user
equipment.
[0046] Some of the example embodiments are directed towards a base
station for determining a control timing configuration. The control
timing configuration provides a subframe timing setting for
configuring downlink HARQ-ACK control timing for a cell serving a
user equipment in a multiple cell communications network. The user
equipment is served by a TDD based cell and a FDD based cell.
[0047] The base station comprises processing circuitry configured
to determine a control timing configuration for a secondary cell.
The secondary cell is one of the TDD based cell or the FDD based
cell. The processing circuitry is configured to determine the
control timing configuration based on a control timing
configuration of a primary cell. The primary cell is one of the FDD
based cell or the TDD based cell, respectively. The processing
circuitry is further configured to implement the control timing
configuration for downlink HARQ-ACK control timing for a cell
serving the user equipment.
[0048] Some of the example embodiments are directed towards a
method, in a user equipment, for determining a control timing
configuration. The control timing configuration provides a subframe
timing setting for configuring downlink HARQ-ACK control timing for
a cell serving the user equipment in a multiple cell communications
network. The user equipment is served by a TDD based cell and a FDD
based cell.
[0049] The method comprises determining a control timing
configuration for a secondary cell. The secondary cell is one of
the TDD based cell or the FDD based cell. The determining is based
on a control timing configuration of a primary cell. The primary
cell is one of the FDD based cell or the TDD based cell,
respectively. The method further comprises implementing the control
timing configuration for downlink HARQ-ACK control timing for a
cell serving the user equipment.
[0050] Some of the example embodiments are directed towards a user
equipment for determining a control timing configuration. The
control timing configuration provides a subframe timing setting for
configuring downlink HARQ-ACK control timing for a cell serving the
user equipment in a multiple cell communications network. The user
equipment is served by a TDD based cell and a FDD based cell.
[0051] The user equipment comprises processing circuitry configured
to determine a control timing configuration for a secondary cell.
The secondary cell is one of the TDD based cell or the FDD based
cell. The determination of the control timing configuration is
based on a control timing configuration of a primary cell. The
primary cell is one of the FDD based cell or the TDD based cell,
respectively. The processing circuitry is further configured to
implement the control timing configuration for downlink HARQ-ACK
control timing for a cell serving the user equipment.
Definitions
[0052] ACK Acknowledgement
[0053] AL Aggregation Level
[0054] ARQ Automatic Repeat reQuest
[0055] BPSK Binary Phase Shift Keying
[0056] C-RNTI Cell Radio Network Temporary Identifier
[0057] CA Carrier Aggregation
[0058] CAZAC Constant Amplitude Zero Autocorrelation
[0059] CC Component Carrier
[0060] CCE Control-Channel Elements
[0061] CFI Control Format Indicator
[0062] CIF Carrier Indicator Field
[0063] CRC Cyclic Redundancy Check
[0064] DCI Downlink Control Information
[0065] DFT Discrete Fourier Transform
[0066] DFTS DFT Spread
[0067] DL Downlink
[0068] DTX Discontinuous Transmission
[0069] DwPTS Downlink Part of a Special Subframe
[0070] ePDCCH enhanced Physical Downlink Control Channel
[0071] GP Guard Period
[0072] FDD Frequency Division Duplexing
[0073] HARQ Hybrid Automatic Repeat Request
[0074] LTE Long Term Evolution
[0075] MAC Medium Access Control
[0076] NACK Non-Acknowledgement
[0077] NW Network
[0078] OFDM Orthogonal Frequency Division Multiplexing
[0079] PCell Primary Cell
[0080] PCC Primary CC
[0081] PDCCH Physical Downlink Control Channel
[0082] PDSCH Physical Downlink Shared Channel
[0083] PRB Physical Resource Blocks
[0084] PUCCH Physical Uplink Control Channel
[0085] PUSCH Physical Uplink Shared Channel
[0086] QPSK Quadrature Phase Shift Keying
[0087] REG Resource Element Group
[0088] RNTI Radio Network Temporary Identifier
[0089] RRC Radio Resource Control
[0090] SCell Secondary Cell
[0091] SCC Secondary CC
[0092] TDD Time Division Duplexing
[0093] TPC Transmit Power Control
[0094] UE User Equipment
[0095] UL Uplink
[0096] UpPTS Uplink Part of a Special Subframe
[0097] VRB Virtual Resource Blocks
BRIEF DESCRIPTION OF THE DRAWINGS
[0098] The foregoing will be apparent from the following more
particular description of the example embodiments, as illustrated
in the accompanying drawings in which like reference characters
refer to the same parts throughout the different views. The
drawings are not necessarily to scale, emphasis instead being
placed upon illustrating the example embodiments.
[0099] FIG. 1 is an illustrative example of frequency and time
division duplex;
[0100] FIG. 2 is an illustrative example of an uplink/downlink
time/frequency structure for LTE in the case of FDD and TDD;
[0101] FIG. 3 is an illustrative example of the different
uplink/downlink TDD configurations;
[0102] FIGS. 4A and 4B are illustrative examples of PDSCH A/N
feedback timings;
[0103] FIGS. 5 and 6 are illustrative examples of PDSCH A/N
feedback timings for an aggregation of a configuration 1 cell and a
configuration 2 cell;
[0104] FIGS. 7 and 8 illustrate examples of control timing for FDD
and TDD aggregated cells, according to some of the example
embodiments;
[0105] FIG. 9 illustrates a subframe configuration hierarchy
according to some of the example embodiments;
[0106] FIGS. 10-13 further illustrate examples of control timing
for FDD and TDD aggregated cells, according to some of the example
embodiments;
[0107] FIG. 14 illustrates an example node configuration of a base
station, according to some of the example embodiments;
[0108] FIG. 15 illustrates an example node configuration of a user
equipment, according to some of the example embodiments;
[0109] FIG. 16 is a flow diagram illustrating example operations
which may be carried out by the base station of FIG. 14, according
to some of the example embodiments; and
[0110] FIG. 17 is a flow diagram illustrating example operations
which may be carried out by the user equipment of FIG. 15,
according to some of the example embodiments.
DETAILED DESCRIPTION
[0111] In the following description, for purposes of explanation
and not limitation, specific details are set forth, such as
particular components, elements, techniques, etc. in order to
provide a thorough understanding of the example embodiments.
However, the example embodiments may be practiced in other manners
that depart from these specific details. In other instances,
detailed descriptions of well-known methods and elements are
omitted so as not to obscure the description of the example
embodiments.
[0112] As part of the development of the example embodiments
presented herein, a problem will first be identified and
discussed.
[0113] Interband TDD carrier aggregation with different UL-DL
configurations on different carriers.
[0114] In LTE Release 10, carrier aggregation of TDD cells is
specified with the restriction that the U/D configurations for all
the aggregated cells are identical. The need to allow more flexible
carrier aggregation of TDD cells is to be addressed in Release 11
of LTE.
[0115] The U/D configurations of neighboring cells need to be
compatible to avoid severe interference problems. However, there
are cases where the neighboring cells are operated by different
operators or different wireless systems. The LTE TDD cells adjacent
to those neighboring systems are hence required to adopt certain
compatible U/D configurations. As a result, an operator may have
several TDD cells having different U/D configurations on different
frequencies.
[0116] To solve the HARQ control and A/N feedback timings in
carrier aggregation systems with cells of different UL-DL
configurations, WO2013/025143 and 3GPP TS 36.211 V11.1.0 3rd
Generation Partnership Project; Technical Specification Group Radio
Access Network; Evolved Universal Terrestrial Radio Access
(E-UTRA); Physical channels and modulation (Release 11), taught
that a user equipment is configured with at least one of two timing
configuration numbers. The first timing configuration number is a
PDSCH HARQ control timing configuration number for determining
PDSCH HARQ A/N timings across all aggregated cells. The second
timing configuration number is a PUSCH control timing configuration
number for determining PUSCH scheduling and the corresponding HARQ
A/N timings on PHICH across all aggregated cells.
[0117] As an example to illustrate the mechanism discussed above,
consider the PDSCH A/N feedback timing for a configuration 1 cell
and a configuration 2 cell shown in FIG. 5. For a user equipment
configured with these two serving cells, the DL HARQ control timing
configuration number may be set to configuration number 2.
Accordingly, as described in Table 1, configuration 2 provides for
HARQ A/N feedback to be received in subframes 2 and 7. Utilizing
the n-k calculation, it is determined that such HARQ A/N feedbacks
are for PDSCHs transmitted in subframes 0, 1, 3, 4, 5, 6 and 9. As
shown in FIG. 5, the topmost cell is denoted as the primary cell
(PCell) and the bottommost cell is denoted as the secondary cell
(SCell). As illustrated in FIG. 5, HARQ A/N feedbacks originating
from the SCell are scheduled in the PCell. FIG. 6 illustrates a
similar system as provided in FIG. 5. However, in FIG. 6, it is the
bottom most cell which serves as the PCell.
[0118] Overview of the Example Embodiments
[0119] In current 3GPP standards, the possibility of a user
equipment being served by an aggregated FDD and TDD carrier
simultaneously is not discussed or addressed. Thus, at least one
example object of the example embodiments presented herein is to
provide mechanisms to provide downlink scheduling and HARQ control
timing for FDD and TDD carrier aggregated network.
[0120] Therefore, some of the example embodiments presented herein
are directed towards how to allocate the HARQ timing and scheduling
timing for PDSCH transmission, for example, DL HARQ. According to
some of the example embodiments, depending on which if either FDD
or a certain UL/DL configuration for TDD is used, an applicable
reference configuration is selected for the HARQ timing. An
advantage of the example embodiments is the ability to provide a
simple scheme to derive the subframes for the timing of HARQ and
scheduling for TDD and FDD aggregation.
[0121] The applicable scheduling and HARQ timing for a user
equipment performing aggregation between a FDD carrier and a TDD
carrier depends on which of the carriers the scheduling is
performed from. In addition, what impacts the applicable timings
are whether the user equipment is configured with cross-carrier
scheduling or not. The example embodiments are mostly described
from the basis of only aggregation between two carriers although it
is assumed that the aggregation may also be extended to more than
two carriers.
[0122] In this section, the example embodiments will be illustrated
in more detail by a number of examples. It should be noted that
these examples are not mutually exclusive. Components from one
example embodiment may be tacitly assumed to be present in another
embodiment and a person skilled in the art may use any number of
the example embodiments in other example embodiments.
[0123] The example embodiments will be presented as follows. First,
example embodiments directed towards the self-scheduling of each
individual cell serving a user equipment is provided under the
subheading `DL HARQ-ACK timing for self-scheduling`. In such
example embodiments, scheduling of a secondary cell is provided
based on a configuration (e.g., configuration number) or type
(e.g., TDD or FDD) of a primary cell serving the user equipment.
Some example embodiments are provided with the FDD based cell
functioning as the primary cell. In such example embodiments, the
TDD based cell therefore functions as the secondary cell. These
example embodiments are discussed under the subheading `FDD carrier
as the PCell`.
[0124] Some example embodiments are provided where the TDD based
cell functions as the primary cell and the FDD based cell therefore
functions as the secondary cell, as discussed under the subheading
`TDD carrier as the PCell`. According to these example embodiments,
scheduling of the secondary FDD cell may be based on a
configuration of the TDD primary cell, as discussed under the
subheading `HARQ scheduling based on PCell configuration`.
According to some of the example embodiments, the scheduling of the
FDD secondary cell may be based on a subframe hierarchy as
described under the subheading `HARQ scheduling based on subframe
hierarchy`. According to some of the example embodiments, the
scheduling of the FDD secondary cell may be based on newly provided
or altered configuration sets, as described under the subheadings
`HARQ scheduling based on association sets` and `HARQ scheduling
based on extended association sets`.
[0125] Example embodiments directed towards cross-carrier
scheduling are also provided under the subheading `DL HARQ-ACK
timing for cross-carrier scheduling configuration`. Finally,
example node configurations and example node operations are
provided under the subheadings "Example node configuration" and
"Example node operations", respectively.
[0126] DL HARQ-ACK Timing for Self-Scheduling Configuration
[0127] A self-scheduling configuration provides for the PDSCH
scheduling information to be transmitted via the PDCCH/ePDCCH on
each individual aggregated serving cell.
[0128] FDD Carrier as the PCell
[0129] According to some of the example embodiments, when the TDD
based cell functions as the SCell, PDSCH HARQ feedback timing
follows a new PDSCH HARQ timing reference configuration referred to
as the UL/DL configuration number F, which is defined in the
extended downlink association set in Table 2. The added
configuration in Table 2 is denoted with bold and underlined
text.
TABLE-US-00002 TABLE 2 Extended downlink association set index K =
{k.sub.0, k.sub.1, . . . , k.sub.M-1} UL-DL Configu- Subframe n
ration 0 1 2 3 4 5 6 7 8 9 0 6 4 6 4 1 7, 6 4 7, 6 4 2 8, 7, 4, 8,
7, 6 4, 6 3 7, 6, 11 6, 5 5,4 4 12, 8, 7, 6, 5, 11 4, 7 5 13, 12,
9, 8, 7, 5, 4, 11, 6 6 7 7 5 7 7 F 4 4 4 4 4 4 4 4 4 4
[0130] An exemplary carrier aggregation case of a FDD PCell and a
TDD configuration #1 SCell according to this embodiment is
illustrated in FIG. 7. As illustrated in FIG. 7, all downlink
subframes of the SCell are scheduled for HARQ feedback in the FDD
based PCell according to the F configuration of Table 2.
Specifically, each HARQ feedback in the FDD is provided for a n-k
subframe of the TDD SCell, where k is four for each subframe.
[0131] TDD Carrier as the Pcell
[0132] HARQ Scheduling Based on PCell Configuration
[0133] According to some of the example embodiments, the FDD SCell
uses the PCell UL/DL configuration as the timing reference
configuration for DL HARQ feedback. Such example embodiments
provide a simplified implementation. However, some DL subframes on
the FDD SCell will not have associated HARQ feedback timing and
hence may not be used for the carrier aggregation user
equipment.
[0134] FIG. 8 illustrates a configuration 1 TDD based cell
functioning as a PCell which is aggregated with a FDD based SCell.
As shown, the FDD based SCell follows the HARQ control timing of
configuration 1, as provided in Tables 1 and 2. Configuration 1
indicates that HARQ feedback be provided in subframes 2, 3, 7 and
8. According to Tables 1 and 2, subframe 2 comprises k values of 7
and 6 for configuration 1. Therefore, HARQ feedback for the PCell
in subframe 2 is provided for downlink transmissions from subframes
5 and 6 from the SCell, as is provided in the modular 10
calculation of n-k.
[0135] Similarly, HARQ feedback for the PCell in subframe 3 is
provided for downlink transmissions from subframe 9 from the SCell;
HARQ feedback for the PCell in subframe 7 is provided for downlink
transmissions from subframes 0 and 1 from the SCell; and HARQ
feedback for the PCell in subframe 8 is provided for downlink
transmissions from subframe 4 from the SCell. Therefore, through
configuration 1, there is no available HARQ scheduling for downlink
transmissions received in subframes 2, 3, 7 and 8 of the FDD SCell,
as is indicated by X's in FIG. 8.
[0136] Thus, it should be appreciated that example embodiments
which provide HARQ scheduling based on the configuration of the
PCell allow for simplified implementation with a potential drawback
being that some of the downlink subframes of the FDD based SCell
may not be available for HARQ control timing.
[0137] HARQ Scheduling Based on Subframe Hierarchy
[0138] According to some of the example embodiments, the choice of
which configuration the SCell shall use for determining HARQ
control timing is based on a subframe hierarchy, as illustrated in
FIG. 9. It should be appreciated that the hierarchical ordering of
FIG. 9 is further described in WO2013/025143.
[0139] The subframe hierarchy may be designed with the following
principles:
[0140] (1) The UL subframes in a TDD configuration are also UL
subframes in those TDD configurations that can be corrected with
upward arrows.
[0141] For example, subframes 2 and 3 are UL subframes in
configuration 4. These two subframes are also UL in configurations
3, 1, 6 and 0, all of which can be connected from configuration 4
with upward arrows. As a second example, subframes 2 and 7 are UL
subframes in configuration 2. These two subframes are not both UL
in configuration 3 because there is no upward arrow connecting the
two configurations.
[0142] (2) The DL subframes in a TDD configuration are also DL
subframes in those TDD configurations that can be corrected with
downward arrows.
[0143] For example, subframe 0, 1, 5, 6 and 9 are DL subframes in
configuration 6. These five subframes are also DL in configurations
1, 2, 3, 4 and 5, all of which can be connected from configuration
6 with downward arrows. As a second example, subframe 7 is a DL
subframe in configuration 3 but not a DL subframe in configuration
2 because there is no downward arrow connecting the two
configurations.
[0144] With these design properties, the subframe hierarchy may
provide the following utility:
[0145] (1) Given a set of TDD configurations to be aggregated, a
TDD configuration that can be connected from all of the given TDD
configurations with upward arrows has the following two
properties:
[0146] The TDD configuration comprises UL subframes that are a
superset of all UL subframes from all given TDD configurations.
[0147] The TDD configuration comprises DL subframes that are
available in all given TDD configurations.
[0148] Given the subframe hierarchy described above, according to
some of the example embodiments, the FDD based SCell may be
configured to always use UL/DL configuration 5 as the timing
reference configuration for DL HARQ feedback regardless of the
configuration associated with the TDD based PCell. Configuration 5
comprises the greatest number of downlink subframes, therefore, by
choosing configuration 5 for DL HARQ feedback, the number of FDD
subframes unavailable for feedback is reduced. As illustrated in
FIG. 8, subframes 2, 3, 7 and 8 are unavailable for DL HARQ
feedback. However, with configuration 5, only subframe 2 of the FDD
based SCell will be unavailable for DL HARQ feedback.
[0149] According to some of the example embodiments, the FDD based
SCell may be configured to use UL/DL configuration 2 as the timing
reference configuration if the UL/DL configuration of the TDD based
PCell is 0, 1, 2 or 6. As illustrated from the hierarchy of FIG. 9,
configuration 2 encompasses all of the same downlink subframes as
configurations 0, 1, 2 and 6. Similarly, according to some of the
example embodiments, the FDD based SCell may be configured to use
UL/DL configuration 5 as the timing reference configuration if the
UL/DL configuration of the TDD based PCell is 3, 4 or 5, as
illustrated in FIG. 10.
[0150] In the example provided in FIG. 10, the TDD based PCell
comprises a configuration of 0. Thus, based on the subframe
hierarchy, a UL/DL configuration of 2 is used as the timing
reference configuration. As provided in Tables 1 and 2, a UL/DL
configuration of 2 provides for all HARQ feedback to be sent to
subframes 2 and 7.
[0151] HARQ scheduling based on association sets
[0152] According to some of the example embodiments, HARQ control
timing may be determined based on an association set. For an
association set K of a UL/DL configuration X, let the k.sub.min and
k.sub.max denote the smallest and the large values in the
association set K. The completed association set is then given by
K* ={k.sub.min, k.sub.min+1, . . . , k.sub.max}. For example, for
UL/DL configuration 2, the association K={8,7,4,6} gives
k.sub.min=4 and k.sub.max=8. Therefore, the completed association
set is K={8,7,4,6,5}.
[0153] This association set completion may be computed by the eNB
and user equipment as part of the TDD+FDD carrier aggregation
configuration. Alternatively, the completed association sets may be
pre-computed and stored in a nonvolatile memory. Furthermore, the
completed association may be described in the system operation
specification such as 3GPP TS 36.213.
[0154] For ease of describing the embodiments in the following,
Table 3 is provided with calculated association sets which are
labelled with starred UL/DL configuration numbers. Thus, a "FDD
SCell which uses UL/DL configuration 2* as the timing reference
configuration," means that the DL HARQ timing of the FDD SCell is
defined by the completed association sets tabulated in the 2* row
of Table 3. In Table 3, the values added via association are
denoted in bold and underlined text.
TABLE-US-00003 TABLE 3 Completed downlink association set index K =
{k.sub.0, k.sub.1, . . . , k.sub.M-1} UL-DL Configu- Subframe n
ration 0 1 2 3 4 5 6 7 8 9 2* 8, 7, 4, 8, 7, 6, 5 4, 6, 5 3* 7, 6,
11, 6, 5 5, 4 10, 9, 8 4* 12, 8, 7, 6, 5, 11, 10, 9 4, 7 5* 13, 12,
9, 8, 7, 5, 4, 11, 6, 10
[0155] Thus, according to some of the example embodiments, the FDD
based SCell may be configured to use UL/DL configuration 2* as the
timing reference configuration if the UL/DL configuration of the
TDD based PCell is 0, 1, 2 or 6. Similarly, the FDD based SCell may
be configured to use UL/DL configuration 5* as the timing reference
configuration if the UL/DL configuration of the TDD based PCell is
3, 4 or 5.
[0156] According to some of the example embodiments, the FDD based
SCell may be configured to use UL/DL configuration 2* as the timing
reference configuration if the UL/DL configuration of the TDD based
PCell is 0, 1, 2 or 6. The FDD based SCell may be configured to use
UL/DL configuration 3* as the timing reference configuration if the
UL/DL configuration of the TDD based PCell is 3. The FDD based
SCell may be configured to use UL/DL configuration 4* as the timing
reference configuration if the UL/DL configuration of the TDD based
PCell is 4. The FDD based SCell may be configured to use UL/DL
configuration 5* as the timing reference configuration if the UL/DL
configuration of the TDD based PCell is 5. Thus, according to this
example embodiment, the timing reference configuration is N* if the
configuration of the TDD based PCell is N, where N is an integer
from 3-5.
[0157] The determination of which associated set to use is based on
the subframe hierarchy as described in the above section. With the
use of associated sets, the problem of certain downlink frames
being unavailable for HARQ feedback is avoided.
[0158] FIG. 11 illustrates a similar configuration as FIG. 10,
where the TDD based PCell comprises a configuration of 0. In FIG.
11, the FDD based SCell uses configuration 2* for HARQ control
timing. In contrast to the HARQ feedback of FIG. 10, the feedback
timings of FIG. 11 feature HARQ feedback for subframes 2 and 7,
denoted by bold and dashed lines. The HARQ feedback originating
from subframes 2 and 7, in FIG. 11, is provided by the added k
value of 5 in associated set 2* for subframes 2 and 7. Thus, all of
the downlink subframes may provide HARQ feedback with the use of
the associated set.
[0159] HARQ Scheduling Based on Extended Association Sets
[0160] It may be observed that the number of HARQ-ACK feedback bits
per feedback period, according to the example embodiments in the
previous section, may become large for certain TDD+FDD carrier
aggregation combinations. This concept is illustrated in FIG. 11.
In FIG. 11 subframe number 2 is a PCell UL in which the user
equipment will send HARQ-ACK feedback. The figure illustrates that
the user equipment needs to send HARQ-ACK for 6 subframes (1
subframe for PCell and 5 subframes for SCell). The user equipment
will then need to send 6 or 12 bits in this UL subframe depending
on whether the UL is configured PDSCH of one or two transport
blocks.
[0161] To further improve upon this aspect, a more sophisticated
association set completion may be provided. For instance, the set
completion computation for UL/DL configuration 1 may impose the
k.sub.min=4 condition in some subframes. The term k.sub.minis the
minimum value of the association set K. The extended completed
association sets are tabulated in Table 4. In Table 4, the values
added via extended association are denoted in bold and underlined
text.
TABLE-US-00004 TABLE 4 Extended completed downlink association set
index K = {k.sub.0, k.sub.1, . . . , k.sub.M-1} UL-DL Configu-
Subframe n ration 0 1 2 3 4 5 6 7 8 9 0* 6, 4, 5 6, 4, 5 5, 4 5, 4
1* 7, 6, 4 7, 6, 4 5, 4 5, 4 6* 7 7, 5 7, 6, 7 6, 5 5, 4
[0162] Combining the configurations of Table 3 with the
configurations of Table 4 yields a fully extended association
configuration set provided below in Table 5.
TABLE-US-00005 TABLE 5 Extended completed downlink association set
index K = {k.sub.0, k.sub.1, . . . , k.sub.M-1} UL-DL Configu-
Subframe n ration 0 1 2 3 4 5 6 7 8 9 0* 6, 5, 4, 5 6, 5, 4, 5 4 4
1* 7, 6, 4 7, 6, 4 5, 4 5, 4 2* 8, 7, 8, 7, 4, 6, 4, 6, 5 5 3* 7,
6, 6, 5 5, 4 11, 10, 9, 8 4* 12, 8, 6, 5, 7, 11, 4, 7 10, 9 5* 13,
12, 9, 8, 7, 5, 4, 11, 6, 10 6* 7 7, 6, 5 7, 6, 7 5 5, 4
[0163] According to some of the example embodiments, the FDD based
SCell may be configured to use UL/DL configuration 1* as the timing
reference configuration if the UL/DL configuration of the TDD based
PCell is 0, 1 or 6. The FDD based SCell may be configured to use
UL/DL configuration 2* as the timing reference configuration if the
UL/DL configuration of the TDD based PCell is 2. The FDD based
SCell may be configured to use UL/DL configuration 3* as the timing
reference configuration if the UL/DL configuration of the TDD based
PCell is 3. The FDD based SCell may be configured to use UL/DL
configuration 4* as the timing reference configuration if the UL/DL
configuration of the TDD based PCell is 4. The FDD based SCell may
be configured to use UL/DL configuration 5* as the timing reference
configuration if the UL/DL configuration of the TDD based PCell is
5.
[0164] FIG. 12 illustrates the example embodiment described above.
In FIG. 12, the TDD based PCell comprises a configuration of 0 and
the FDD based SCell uses configuration 1* for HARQ control timing.
For configuration 1*, Table 5 provides extended k values of 5 and 4
for subframes 2 and 7. As a result, additional HARQ feedback is
provided from the FDD based cell in subframes 7 and 8 to TDD
subframe 2. Further additional HARQ feedback is provided from the
FDD based cell in subframes 2 and 3 to TDD subframe 7. It should be
appreciated that the example embodiment described above and in FIG.
12 is provided with use of the hierarchical order of configuration
numbers as described in FIG. 9. It should further be appreciated
that via a comparison of FIGS. 11 and 12, a reduction in the
maximum number of HARQ-ACK bits per feedback from 6 to 5 has
occurred.
[0165] According to some of the example embodiments, the FDD based
SCell uses UL/DL configuration X* as the timing reference
configuration if the UL/DL configuration of the TDD based PCell is
X. An example according to this embodiment is illustrated in FIG.
13. In FIG. 13, the TDD based PCell comprises a configuration of 0
and the FDD based SCell uses configuration 0* for HARQ control
timing. Comparing FIG. 12 and FIG. 13, a reduction in the maximum
number of HARQ-ACK bits per feedback period from 5 to 4 may be
observed.
[0166] DL HARQ-ACK Timing for Cross-Carrier Scheduling
Configuration
[0167] According to some of the example embodiments, downlink
HARQ-ACK is provided in a cross-carrier scheduling configuration.
According to these example embodiments, the PDSCH scheduling
information for a SCell is transmitted via the PDCCH/EPDCCH on
another serving cell, which may be the PCell or a different SCell
but, in most applicable cases, it is the PCell.
[0168] According to some of the example embodiments, if the PCell
is the FDD carrier, a TDD SCell shall follow the DL HARQ timing
defined by the UL/DL configuration F in the extended DL association
set of Table 2. According to some of the example embodiments, if
the PCell is a TDD carrier, a FDD SCell shall follow the DL HARQ
timings defined by the UL/DL configuration of the TDD PCell.
[0169] Example Node Configurations
[0170] FIG. 14 illustrates an example node configuration of a base
station 401 which may perform some of the example embodiments
described herein. The base station 401 may comprise radio circuitry
or a communication port 410 that may be configured to receive
and/or transmit communication data, instructions, and/or messages.
It should be appreciated that the radio circuitry or communication
port 410 may comprise any number of transceiving, receiving, and/or
transmitting units or circuitry. It should further be appreciated
that the radio circuitry or communication port 410 may be in the
form of any input or output communications port known in the art.
The radio circuitry or communication port 410 may comprise RF
circuitry and baseband processing circuitry (not shown).
[0171] The base station 401 may also comprise a processing unit or
circuitry 420 which may be configured to implement HARQ-ACK control
timing as described herein. The processing circuitry 420 may be any
suitable type of computation unit, for example, a microprocessor,
digital signal processor (DSP), field programmable gate array
(FPGA), or application specific integrated circuit (ASIC), or any
other form of circuitry. The base station 401 may further comprise
a memory unit or circuitry 430 which may be any suitable type of
computer readable memory and may be of volatile and/or non-volatile
type. The memory 430 may be configured to store received,
transmitted, and/or measured data, device parameters, communication
priorities, and/or executable program instructions, e.g.,
scheduling instructions. The memory 430 may also be configured to
store any form of configuration tables as described herein.
[0172] FIG. 15 illustrates an example node configuration of a user
equipment 501 which may perform some of the example embodiments
described herein. The user equipment 501 may comprise radio
circuitry or a communication port 510 that may be configured to
receive and/or transmit communication data, instructions, and/or
messages. It should be appreciated that the radio circuitry or
communication port 510 may comprise any number of transceiving,
receiving, and/or transmitting units or circuitry. It should
further be appreciated that the radio circuitry or communication
port 510 may be in the form of any input or output communications
port known in the art. The radio circuitry or communication port
510 may comprise RF circuitry and baseband processing circuitry
(not shown).
[0173] The user equipment 501 may also comprise a processing unit
or circuitry 520 which may be configured to implement HARQ-ACK
control timing, as described herein. The processing circuitry 520
may be any suitable type of computation unit, for example, a
microprocessor, digital signal processor (DSP), field programmable
gate array (FPGA), or application specific integrated circuit
(ASIC), or any other form of circuitry. The user equipment 501 may
further comprise a memory unit or circuitry 530 which may be any
suitable type of computer readable memory and may be of volatile
and/or non-volatile type. The memory 530 may be configured to store
received, transmitted, and/or measured data, device parameters,
communication priorities, and/or executable program instructions,
e.g., scheduling instructions. The memory 530 may also be
configured to store any form of configuration tables as described
herein.
[0174] Example Node Operations
[0175] FIG. 16 is a flow diagram depicting example operations which
may be performed by the base station 401 as described herein to
implement HARQ-ACK control timing, as described herein. It should
be appreciated that FIG. 16 comprises some operations which are
illustrated with a solid border and some operations which are
illustrated with a dashed border. The operations which are
comprised in a solid border are operations which are comprised in
the broadest example embodiment. The operations which are comprised
in a dashed border are example embodiments which may be comprised
in, or a part of, or are further operations which may be performed
in addition to the operations of the broader example embodiments.
It should be appreciated that these operations need not be
performed in order. Furthermore, it should be appreciated that not
all of the operations need to be performed. The example operations
may be performed in any order and in any combination.
[0176] Operation 10
[0177] The base station is configured to determine 10 a control
timing configuration for a secondary cell (SCell). The secondary
cell is one of a TDD based cell or a FDD based cell. The
determining 10 is based on a control timing configuration of a
primary cell (PCell). The primary cell is one of the FDD based cell
or the TDD based cell, respectively. The processing circuitry 420
is configured to determine the control timing configuration for the
secondary cell.
[0178] Example Operation 12
[0179] According to some of the example embodiments, the primary
cell may be a FDD based cell and the secondary cell may be a TDD
based cell. According to these example embodiments, the determining
10 may further comprise determining 12 the control timing
configuration to comprise a HARQ-ACK feedback timing value of 4 for
all subframes. The processing circuitry 420 is configured to
determine the control timing configuration to comprise a HARQ-ACK
feedback timing value of 4 for all subframes.
[0180] Example operation 12 is further described under at least the
subheadings `FDD carrier as the PCell` and `DL HARQ-ACK timings for
cross-carrier scheduling configuration`, Table 2 and FIG. 7.
[0181] Example Operation 14
[0182] According to some of the example embodiments, the primary
cell may be a TDD based cell and the secondary cell may be a FDD
based cell. According to some of these example embodiments, the
determining 10 may further comprise determining 14 the control
timing configuration to be equivalent to a TDD configuration of the
primary cell. The processing circuitry 420 is configured to
determine the control timing configuration to be equivalent to the
TDD configuration of the primary cell.
[0183] Example operation 14 is further described under at least the
subheadings `HARQ scheduling based on PCell configuration` and `DL
HARQ-ACK timings for cross-carrier scheduling configuration` and
FIG. 8.
[0184] Example Operation 16
[0185] According to some of the example embodiments, the primary
cell may be a TDD based cell and the secondary cell may be a FDD
based cell. According to some of these example embodiments, the
determining 10 may further comprise determining 16 the control
timing configuration to be configuration 2 if the configuration
number of the primary cell is 0, 1, 2 or 6; or determining 16 the
control timing configuration to be 5 if the configuration number of
the primary cell is 3, 4 or 5. The processing circuitry is
configured to determine the control timing configuration to be
configuration 2 if the configuration number of the primary cell is
0, 1, 2 or 6; or configuration 5 is the configuration number of the
primary cell is 3, 4 or 5.
[0186] Example operation 14 is further described under at least the
subheading `HARQ scheduling based on subframe hierarchy` and FIGS.
9 and 10.
[0187] Example Operation 18
[0188] According to some of the example embodiments, the primary
cell may be a TDD based cell and the secondary cell may be a FDD
based cell. According to some of these example embodiments, the
determining 10 may further comprise determining 18 the control
timing configuration based on a first altered configuration table.
The first altered configuration table is provided below:
TABLE-US-00006 UL-DL Configu- Subframe n ration 0 1 2 3 4 5 6 7 8 9
2* 8, 7, 8, 7, 4, 6, 4, 6, 5 5 3* 7, 6, 6, 5 5, 4 11, 10, 9, 8 4*
12, 8, 6, 5, 7, 11, 4, 7 10, 9 5* 13, 12, 9, 8, 7, 5, 4, 11, 6,
10
[0189] The processing circuitry 420 is configured to determine the
control timing configuration based on the first alteration
configuration table provided above.
[0190] Example operation 18 is described further under at least the
subheading `HARQ scheduling based on association sets`, Table 3 and
FIG. 11.
[0191] Example Operation 20
[0192] According to some of the example embodiments, the
determining 18 may further comprise determining 20 the control
timing configuration to be 2* (as provided in the first altered
configuration table) if the control timing configuration of the
primary cell is 0, 1, 2 or 6; or configuration 5* (as provided in
the first altered configuration table) if the control timing
configuration of the primary cell is 3, 4 or 5. The processing
circuitry 420 is configured to determine the control timing
configuration to be 2* (as provided in the first altered
configuration table) if the control timing configuration of the
primary cell is 0, 1, 2 or 6; or configuration 5* (as provided in
the first altered configuration table) if the control timing
configuration of the primary cell is 3, 4 or 5.
[0193] Example operation 20 is further described under at least the
subheading `HARQ scheduling based on association sets`, Table 3 and
FIG. 11. It should be appreciated that the choice of configuration
2* and configuration 5* is provided via the subframe hierarchy
described under at least the subheading `HARQ scheduling based on
subframe hierarchy` and FIG. 9.
[0194] Example Operation 22
[0195] According to some of the example embodiments, the
determining 18 may further comprise determining 22 the control
timing configuration to be 2* if the control timing configuration
of the primary cell is 0, 1, 2 or 6; or N* if the control timing
configuration of the primary cell is N, where N is an integer with
a value of 3-5. The processing circuitry 420 is further configured
to determine the control timing configuration to be 2* if the
control timing configuration of the primary cell is 0, 1, 2 or 6;
or N* if the control timing configuration of the primary cell is N,
where N is an integer with a value of 3-5.
[0196] Example operation 22 is further described under at least the
subheading `HARQ scheduling based on association sets`, Table 3 and
FIG. 11. It should be appreciated that the choice of configuration
2* for primary cells with a control timing configuration of 0, 1, 2
or 6 is provided via the subframe hierarchy described under at
least the subheading `HARQ scheduling based on subframe hierarchy`
and FIG. 9.
[0197] Example Operation 24
[0198] According to some of the example embodiments, the primary
cell may be a TDD based cell and the secondary cell may be a FDD
based cell. According to some of these example embodiments, the
determining 10 may further comprise determining 24 the control
timing configuration based on a second altered configuration table.
The second altered configuration table is provided below:
TABLE-US-00007 UL-DL Configu- Subframe n ration 0 1 2 3 4 5 6 7 8 9
1* 7, 6, 4 7, 6, 4 5, 4 5, 4 2* 8, 7, 8, 7, 4, 6, 4, 6, 5 5 3* 7,
6, 6, 5 5, 4 11, 10, 9, 8 4* 12, 8, 6, 5, 7, 11, 4, 7 10, 9 5* 13,
12, 9, 8, 7, 5, 4, 11, 6, 10
[0199] The processing circuitry 420 is configured to determine the
control timing configuration based on the second altered
configuration table provided above.
[0200] Example operation 24 is described further under the
subheading `HARQ scheduling based on extended association sets`,
Tables 4 and 5, and FIGS. 12 and 13.
[0201] Example Operation 26
[0202] According to some of the example embodiments, the
determining 24 further comprises determining 26 the control timing
configuration to be 1* (from the second altered configuration table
provided in example operation 24) if the control timing
configuration of the primary cell is 0, 1 or 6; or N* if the
control timing configuration of the primary cell is N, where N is
an integer valued from 2-5. The processing circuitry 420 is
configured to determine the control timing configuration to be 1*
(from the second altered configuration table provided in example
operation 24) if the control timing configuration of the primary
cell is 0, 1 or 6; or N* if the control timing configuration of the
primary cell is N, where N is an integer valued from 2-5.
[0203] Example operation 26 is further described under at least the
sub-heading `HARQ scheduling based on extended association sets`,
Tables 4 and 5, and FIGS. 12 and 13. It should be appreciated that
the choice of configuration 1* for primary cells with a control
timing configuration of 0, 1, or 6 is provided via the subframe
hierarchy described under at least the subheading `HARQ scheduling
based on subframe hierarchy` and FIG. 9.
[0204] Example Operation 28
[0205] According to some of the example embodiments, the primary
cell may be a TDD based cell and the secondary cell may be a FDD
based cell. According to some of these example embodiments, the
determining 10 may further comprise determining 28 the control
timing configuration based on a third altered configuration table.
The third altered configuration table is provided below:
TABLE-US-00008 UL-DL Configu- Subframe n ration 0 1 2 3 4 5 6 7 8 9
0* 6, 5, 4, 5 6, 5, 4, 5 4 4 1* 7, 6, 4 7, 6, 4 5, 4 5, 4 2* 8, 7,
8, 7, 4, 6, 4, 6, 5 5 3* 7, 6, 6, 5 5, 4 11, 10, 9, 8 4* 12, 8, 6,
5, 7, 11, 4, 7 10, 9 5* 13, 12, 9, 8, 7, 5, 4, 11, 6, 10 6* 7 7, 6,
5 7, 6, 7 5 5, 4
[0206] The processing circuitry 420 is configured to determine the
control timing configuration based on the third altered
configuration table provided above.
[0207] Example operation 28 is further described under at least the
subheading `HARQ scheduling based on extended association sets`,
Tables 4 and 5, and FIGS. 12 and 13.
[0208] Example Operation 30
[0209] According to some of the example embodiments, the
determining 28 may further comprise determining 30 the control
timing configuration to be N* if the control timing configuration
of the primary cell is N, where N is an integer valued from 0-6.
The processing circuitry 420 is configured to determine the control
timing configuration to be N* if the control timing configuration
of the primary cell is N, where N is an integer valued from
0-6.
[0210] Example operation 30 is further described under at least the
subheading `HARQ scheduling based on extended association sets`,
Tables 4 and 5, and FIGS. 12 and 13.
[0211] Operation 32
[0212] The base station is also configured to implement 32 the
control timing configuration for downlink HARQ-ACK control timing
for a cell serving the user equipment. The processing circuitry 420
is configured to implement the control timing configuration for
downlink HARQ-ACK control timing for a cell serving the user
equipment.
[0213] Example Operation 34
[0214] According to some of the example embodiments, the base
station is further configured to send 34, to the user equipment,
the implemented control configuration via RRC signalling. The radio
circuitry 410 is configured to send, to the user equipment, the
implemented control configuration via RRC signalling.
[0215] FIG. 17 is a flow diagram depicting example operations which
may be performed by the user equipment 501 as described herein to
implement HARQ-ACK control timing, as described herein. It should
be appreciated that FIG. 17 comprises some operations which are
illustrated with a solid border and some operations which are
illustrated with a dashed border. The operations which are
comprised in a solid border are operations which are comprised in
the broadest example embodiment. The operations which are comprised
in a dashed border are example embodiments which may be comprised
in, or a part of, or are further operations which may be performed
in addition to the operations of the broader example embodiments.
It should be appreciated that these operations need not be
performed in order. Furthermore, it should be appreciated that not
all of the operations need to be performed. The example operations
may be performed in any order and in any combination.
[0216] Operation 40
[0217] The user equipment is configured to determine 40 a control
timing configuration for a secondary cell (SCell). The secondary
cell is one of a TDD based cell or a FDD based cell. The
determining 40 is based on a control timing configuration of a
primary cell (PCell). The primary cell is one of the FDD based cell
or the TDD based cell, respectively. The processing circuitry 520
is configured to determine the control timing configuration for the
secondary cell.
[0218] Example Operation 42
[0219] According to some of the example embodiments, the
determining 40 further comprises receiving 42, from a base station,
the control timing configuration via RRC signalling. The radio
circuitry 510 is further configured to receive, from the base
station, the control timing configuration via RRC signalling.
[0220] Example Operation 44
[0221] According to some of the example embodiments, the primary
cell may be a FDD based cell and the secondary cell may be a TDD
based cell. According to these example embodiments, the determining
40 may further comprise determining 44 the control timing
configuration to comprise a HARQ-ACK feedback timing value of 4 for
all subframes. The processing circuitry 520 is configured to
determine the control timing configuration to comprise a HARQ-ACK
feedback timing value of 4 for all subframes.
[0222] Example operation 44 is further described under at least the
subheadings `FDD carrier as the PCell` and `DL HARQ-ACK timings for
cross-carrier scheduling configuration`, Table 2 and FIG. 7.
[0223] Example Operation 46
[0224] According to some of the example embodiments, the primary
cell may be a TDD based cell and the secondary cell may be a FDD
based cell. According to some of these example embodiments, the
determining 40 may further comprise determining 46 the control
timing configuration to be equivalent to a TDD configuration of the
primary cell. The processing circuitry 520 is configured to
determine the control timing configuration to be equivalent to the
TDD configuration of the primary cell.
[0225] Example operation 46 is further described under at least the
subheadings `HARQ scheduling based on PCell configuration` and `DL
HARQ-ACK timings for cross-carrier scheduling configuration` and
FIG. 8.
[0226] Example Operation 48
[0227] According to some of the example embodiments, the primary
cell may be a TDD based cell and the secondary cell may be a FDD
based cell. According to some of these example embodiments, the
determining 40 may further comprise determining 48 the control
timing configuration to be configuration 2 if the configuration
number of the primary cell is 0, 1, 2 or 6; or determining 48 the
control timing configuration to be 5 if the configuration number of
the primary cell is 3, 4 or 5. The processing circuitry 520 is
configured to determine the control timing configuration to be
configuration 2 if the configuration number of the primary cell is
0, 1, 2 or 6; or configuration 5 is the configuration number of the
primary cell is 3, 4 or 5.
[0228] Example operation 48 is further described under at least the
subheading `HARQ scheduling based on subframe hierarchy` and FIGS.
9 and 10.
[0229] Example Operation 50
[0230] According to some of the example embodiments, the primary
cell may be a TDD based cell and the secondary cell may be a FDD
based cell. According to some of these example embodiments, the
determining 40 may further comprise determining 50 the control
timing configuration based on a first altered configuration table.
The first altered configuration table is provided below:
TABLE-US-00009 UL-DL Configu- Subframe n ration 0 1 2 3 4 5 6 7 8 9
2* 8, 7, 8, 7, 4, 6, 4, 6, 5 5 3* 7, 6, 6, 5 5, 4 11, 10, 9, 8 4*
12, 8, 6, 5, 7, 11, 4, 7 10, 9 5* 13, 12, 9, 8, 7, 5, 4, 11, 6,
10
[0231] The processing circuitry 520 is configured to determine the
control timing configuration based on the first alteration
configuration table provided above.
[0232] Example operation 50 is described further under at least the
subheading `HARQ scheduling based on association sets`, Table 3 and
FIG. 11.
[0233] Example operation 52
[0234] According to some of the example embodiments, the
determining 50 may further comprise determining 52 the control
timing configuration to be 2* (as provided in the first altered
configuration table) if the control timing configuration of the
primary cell is 0, 1, 2 or 6; or configuration 5* (as provided in
the first altered configuration table) if the control timing
configuration of the primary cell is 3, 4 or 5. The processing
circuitry 520 is configured to determine the control timing
configuration to be 2* (as provided in the first altered
configuration table) if the control timing configuration of the
primary cell is 0, 1, 2 or 6; or configuration 5* (as provided in
the first altered configuration table) if the control timing
configuration of the primary cell is 3, 4 or 5.
[0235] Example operation 52 is further described under at least the
subheading `HARQ scheduling based on association sets`, Table 3 and
FIG. 11. It should be appreciated that the choice of configuration
2* and configuration 5* is provided via the subframe hierarchy
described under at least the subheading `HARQ scheduling based on
subframe hierarchy` and FIG. 9.
[0236] Example Operation 54
[0237] According to some of the example embodiments, the
determining 50 may further comprise determining 54 the control
timing configuration to be 2* if the control timing configuration
of the primary cell is 0, 1, 2 or 6; or N* if the control timing
configuration of the primary cell is N, where N is an integer with
a value of 3-5. The processing circuitry 520 is further configured
to determine the control timing configuration to be 2* if the
control timing configuration of the primary cell is 0, 1, 2 or 6;
or N* if the control timing configuration of the primary cell is N,
where N is an integer with a value of 3-5.
[0238] Example operation 54 is further described under at least the
subheading `HARQ scheduling based on association sets`, Table 3 and
FIG. 11. It should be appreciated that the choice of configuration
2* for primary cells with a control timing configuration of 0, 1, 2
or 6 is provided via the subframe hierarchy described under at
least the subheading `HARQ scheduling based on subframe hierarchy`
and FIG. 9.
[0239] Example Operation 56
[0240] According to some of the example embodiments, the primary
cell may be a TDD based cell and the secondary cell may be a FDD
based cell. According to some of these example embodiments, the
determining 40 may further comprise determining 56 the control
timing configuration based on a second altered configuration table.
The second altered configuration table is provided below:
TABLE-US-00010 UL-DL Configu- Subframe n ration 0 1 2 3 4 5 6 7 8 9
1* 7, 6, 4 7, 6, 4 5, 4 5, 4 2* 8, 7, 8, 7, 4, 6, 4, 6, 5 5 3* 7,
6, 6, 5 5, 4 11, 10, 9, 8 4* 12, 8, 6, 5, 7, 11, 4, 7 10, 9 5* 13,
12, 9, 8, 7, 5, 4, 11, 6, 10
[0241] The processing circuitry 520 is configured to determine the
control timing configuration based on the second altered
configuration table provided above.
[0242] Example operation 56 is described further under the
subheading `HARQ scheduling based on extended association sets`,
Tables 4 and 5, and FIGS. 12 and 13.
[0243] Example Operation 58
[0244] According to some of the example embodiments, the
determining 56 further comprises determining 58 the control timing
configuration to be 1* (from the second altered configuration table
provided in example operation 56) if the control timing
configuration of the primary cell is 0, 1 or 6; or N* if the
control timing configuration of the primary cell is N, where N is
an integer valued from 2-5. The processing circuitry 520 is
configured to determine the control timing configuration to be 1*
(from the second altered configuration table provided in example
operation 56) if the control timing configuration of the primary
cell is 0, 1 or 6; or N* if the control timing configuration of the
primary cell is N, where N is an integer valued from 2-5.
[0245] Example operation 58 is further described under at least the
sub-heading `HARQ scheduling based on extended association sets`,
Tables 4 and 5, and FIGS. 12 and 13. It should be appreciated that
the choice of configuration 1* for primary cells with a control
timing configuration of 0, 1, or 6 is provided via the subframe
hierarchy described under at least the subheading `HARQ scheduling
based on subframe hierarchy` and FIG. 9.
[0246] Example Operation 60
[0247] According to some of the example embodiments, the primary
cell may be a TDD based cell and the secondary cell may be a FDD
based cell. According to some of these example embodiments, the
determining 40 may further comprise determining 60 the control
timing configuration based on a third altered configuration table.
The third altered configuration table is provided below:
TABLE-US-00011 UL-DL Configu- Subframe n ration 0 1 2 3 4 5 6 7 8 9
0* 6, 5, 4, 5 6, 5, 4, 5 4 4 1* 7, 6, 4 7, 6, 4 5, 4 5, 4 2* 8, 7,
8, 7, 4, 6, 5 4, 6, 5 3* 7, 6, 6, 5 5, 4 11, 10, 9, 8 4* 12, 8, 6,
5, 7, 11, 4, 7 10, 9 5* 13, 12, 9, 8, 7, 5, 4, 11, 6, 10 6* 7 7, 6,
5 7, 6, 7 5 5, 4
[0248] The processing circuitry 520 is configured to determine the
control timing configuration based on the third altered
configuration table provided above.
[0249] Example operation 60 is further described under at least the
subheading `HARQ scheduling based on extended association sets`,
Tables 4 and 5, and FIGS. 12 and 13.
[0250] Example Operation 62
[0251] According to some of the example embodiments, the
determining 60 may further comprise determining 62 the control
timing configuration to be N* if the control timing configuration
of the primary cell is N, where N is an integer valued from 0-6.
The processing circuitry 520 is configured to determine the control
timing configuration to be N* if the control timing configuration
of the primary cell is N, where N is an integer valued from
0-6.
[0252] Example operation 62 is further described under at least the
subheading `HARQ scheduling based on extended association sets`,
Tables 4 and 5, and FIGS. 12 and 13.
[0253] Operation 64
[0254] The user equipment is also configured to implement 64 the
control timing configuration for downlink HARQ-ACK control timing
for a cell serving the user equipment. The processing circuitry 520
is configured to implement control timing configuration for
downlink HARQ-ACK control timing for a cell serving the user
equipment.
[0255] It should be noted that although terminology from 3GPP LTE
has been used herein to explain the example embodiments, this
should not be seen as limiting the scope of the example embodiments
to only the aforementioned system. Other wireless systems,
comprising HSPA, WCDMA, WiMax, UMB, WiFi and GSM, may also benefit
from the example embodiments disclosed herein.
[0256] The description of the example embodiments provided herein
have been presented for purposes of illustration. The description
is not intended to be exhaustive or to limit example embodiments to
the precise form disclosed, and modifications and variations are
possible in light of the above teachings or may be acquired from
practice of various alternatives to the provided embodiments. The
examples discussed herein were chosen and described in order to
explain the principles and the nature of various example
embodiments and its practical application to enable one skilled in
the art to utilize the example embodiments in various manners and
with various modifications as are suited to the particular use
contemplated. The features of the embodiments described herein may
be combined in all possible combinations of methods, apparatuses,
modules, systems, and computer program products. It should be
appreciated that the example embodiments presented herein may be
practiced in any combination with each other.
[0257] It should be noted that the word "comprising" does not
necessarily exclude the presence of other elements or steps than
those listed and the words "a" or "an" preceding an element do not
exclude the presence of a plurality of such elements. It should
further be noted that any reference signs do not limit the scope of
the claims, that the example embodiments may be implemented at
least in part by means of both hardware and software, and that
several "means", "units" or "devices" may be represented by the
same item of hardware.
[0258] Also note that terminology such as user equipment should be
considered as non-limiting. A wireless terminal or user equipment
(UE) as the term is used herein, is to be broadly interpreted to
comprise a radiotelephone having ability for Internet/intranet
access, web browser, organizer, calendar, a camera, e.g., video
and/or still image camera, a sound recorder, e.g., a microphone,
and/or global positioning system (GPS) receiver; a personal
communications system (PCS) user equipment that may combine a
cellular radiotelephone with data processing; a personal digital
assistant (PDA) that can comprise a radiotelephone or wireless
communication system; a laptop; a camera, e.g., video and/or still
image camera, having communication ability; and any other
computation or communication device capable of transceiving, such
as a personal computer, a home entertainment system, a television,
etc. It should be appreciated that the term user equipment may also
comprise any number of connected devices, wireless terminals or
machine-to-machine devices.
[0259] It should further be appreciated that the term dual
connectivity should not be limited to a user equipment or wireless
terminal being connected to only two base stations. In dual
connectivity a wireless terminal may be connected to any number of
base stations.
[0260] The various example embodiments described herein are
described in the general context of method steps or processes,
which may be implemented in one aspect by a computer program
product, embodied in a computer-readable medium, comprising
computer-executable instructions, such as program code, executed by
computers in networked environments. A computer-readable medium may
comprise removable and non-removable storage devices comprising,
but not limited to, Read Only Memory (ROM), Random Access Memory
(RAM), compact discs (CDs), digital versatile discs (DVD), etc.
Generally, program modules may comprise routines, programs,
objects, components, data structures, etc. that perform particular
tasks or implement particular abstract data types.
Computer-executable instructions, associated data structures, and
program modules represent examples of program code for executing
steps of the methods disclosed herein. The particular sequence of
such executable instructions or associated data structures
represents examples of corresponding acts for implementing the
functions described in such steps or processes.
[0261] In the drawings and specification, there have been disclosed
exemplary embodiments. However, many variations and modifications
can be made to these embodiments. Accordingly, although specific
terms are employed, they are used in a generic and descriptive
sense only and not for purposes of limitation.
* * * * *