U.S. patent application number 15/138084 was filed with the patent office on 2016-10-20 for system and method for uplink control information transmission in carrier aggregation.
The applicant listed for this patent is BlackBerry Limited. Invention is credited to Andrew Mark Earnshaw, Mo-Han Fong, Robert Mark Harrison, Youn Hyoung Heo, Hua Xu.
Application Number | 20160309460 15/138084 |
Document ID | / |
Family ID | 44310278 |
Filed Date | 2016-10-20 |
United States Patent
Application |
20160309460 |
Kind Code |
A1 |
Heo; Youn Hyoung ; et
al. |
October 20, 2016 |
System and Method for Uplink Control Information Transmission in
Carrier Aggregation
Abstract
A method for communicating uplink control information to a base
station using a user equipment is presented. The method includes
identifying component carriers on the user equipment scheduled for
Physical Uplink Shared CHannel (PUSCH) transmissions, and
identifying at least one first ranking for each of the component
carriers for transmission of uplink control information. Each first
ranking is at least partially determined by whether the component
carrier is configured for delay-sensitive transmissions. The method
includes using the at least one first ranking to select a first
component carrier for transmission of uplink control information,
and encoding uplink control information into the first component
carrier for transmission to the base station.
Inventors: |
Heo; Youn Hyoung; (San Jose,
CA) ; Fong; Mo-Han; (Sunnyvale, CA) ;
Earnshaw; Andrew Mark; (Kanata, CA) ; Xu; Hua;
(Ottawa, CA) ; Harrison; Robert Mark; (Grapevine,
TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
BlackBerry Limited |
Waterloo |
|
CA |
|
|
Family ID: |
44310278 |
Appl. No.: |
15/138084 |
Filed: |
April 25, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14315044 |
Jun 25, 2014 |
9326277 |
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15138084 |
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13159209 |
Jun 13, 2011 |
8767647 |
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14315044 |
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61356537 |
Jun 18, 2010 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04L 5/0053 20130101;
H04W 72/1284 20130101; H04W 72/1242 20130101; H04W 76/27 20180201;
H04L 5/0055 20130101; H04W 72/0406 20130101; H04W 72/0413 20130101;
H04L 5/001 20130101 |
International
Class: |
H04W 72/04 20060101
H04W072/04; H04W 76/04 20060101 H04W076/04; H04L 5/00 20060101
H04L005/00 |
Claims
1. A method at a user equipment (UE) for communicating uplink
control information to a network node, comprising: identifying
component carriers on the UE, wherein the identified component
carriers are scheduled for Physical Uplink Shared Channel (PUSCH)
transmissions and each of the identified component carriers is
associated with a component carrier index; selecting a first
component carrier from the identified component carriers for
transmission of the uplink control information, the selecting being
determined by the component carrier indices, wherein a component
carrier index of the first component carrier is a lowest index
among the component carrier indices; and encoding the uplink
control information into the first component carrier for
transmission to the network node.
2. The method claim of claim 1, wherein the component carrier
indices are provided by radio resource control (RRC) signaling.
3. The method of claim 1, wherein the identified component carriers
are configured for delay-sensitive transmissions, the
delay-sensitive transmissions including at least one of
semi-persistent scheduled transmissions, transmissions using
signaling radio bearers, and medium access control (MAC) control
element transmissions.
4. The method of claim 1, wherein the identified component carriers
are scheduled with a number of physical resource blocks lower than
a threshold; and the method further comprising: responsive to the
number of physical resource blocks being lower than the threshold,
precluding a second uplink component carrier from transmitting the
uplink control information.
5. The method of claim 4, wherein the threshold is determined with
respect to transmission of the uplink control information.
6. The method of claim 5, wherein the threshold is further
determined based on an amount of coded symbols for the uplink
control information.
7. The method of claim 5, wherein the threshold is further
determined based on a number of downlink component carriers
requiring the uplink control information.
8. The method of claim 5, wherein the threshold is further
determined based on a characteristic of the uplink control
information.
9. A user equipment (UE), comprising: a processor configured to:
identify component carriers scheduled for Physical Uplink Shared
Channel (PUSCH) transmissions on the UE, wherein each of the
identified component carriers is associated with a component
carrier index; select a first component carrier from among the
identified component carriers for transmission of uplink control
information to a network node according to the component carrier
indices, wherein a component carrier index of the first component
carrier is a lowest index among the component carrier indices; and
encode the uplink control information into the first component
carrier for transmission to the network node.
10. The UE of claim 9, wherein the component carrier indices are
provided by radio resource control (RRC) signaling.
11. The UE of claim 9, wherein the identified component carriers
are configured for delay-sensitive transmissions including at least
one of semi-persistent scheduled transmissions, transmissions using
signaling radio bearers, and medium access control (MAC) control
element transmissions.
12. The UE of claim 9, wherein the identified component carriers
are scheduled with a number of physical resource blocks lower than
a threshold, and wherein the processor is further configured to
preclude a second uplink component carrier from transmitting the
uplink control information when the number of physical resource
blocks is lower than the threshold.
13. The UE of claim 12, wherein the threshold is determined with
respect to transmission of the uplink control information.
14. The UE of claim 13, wherein the threshold is further determined
based on an amount of coded symbols for the uplink control
information.
15. The UE of claim 13, wherein the threshold is further determined
based on a number of downlink component carriers requiring the
uplink control information.
16. The UE of claim 13, wherein the threshold is further determined
based on a characteristic of the uplink control information.
17. A non-transitory, tangible computer readable storage medium
encoded with computer executable instructions, wherein execution of
the computer executable instructions is for: identifying component
carriers on the UE, wherein the identified component carriers are
scheduled for Physical Uplink Shared Channel (PUSCH) transmissions
and each of the identified component carriers is associated with a
component carrier index; selecting a first component carrier from
the identified component carriers for transmission of the uplink
control information, the selecting being determined by the
component carrier indices, wherein a component carrier index of the
first component carrier is a lowest index among the component
carrier indices; and encoding the uplink control information into
the first component carrier for transmission to the network
node.
18. The non-transitory, tangible computer readable storage medium
of claim 17, wherein the component carrier indices are provided by
radio resource control (RRC) signaling.
19. The non-transitory, tangible computer readable storage medium
of claim 17, wherein the identified component carriers are
configured for delay-sensitive transmissions, the delay-sensitive
transmissions including at least one of semi-persistent scheduled
transmissions, transmissions using signaling radio bearers, and
medium access control (MAC) control element transmissions.
20. The non-transitory, tangible computer readable storage medium
of claim 17, wherein the identified component carriers are
scheduled with a number of physical resource blocks lower than a
threshold; and the method further comprising: responsive to the
number of physical resource blocks being lower than the threshold,
precluding a second uplink component carrier from transmitting the
uplink control information.
21. The non-transitory, tangible computer readable storage medium
of claim 20, wherein the threshold is determined with respect to
transmission of the uplink control information.
22. The non-transitory, tangible computer readable storage medium
of claim 21, wherein the threshold is further determined based on
an amount of coded symbols for the uplink control information.
23. The non-transitory, tangible computer readable storage medium
of claim 21, wherein the threshold is further determined based on a
number of downlink component carriers requiring the uplink control
information.
24. The non-transitory, tangible computer readable storage medium
of claim 21, wherein the threshold is further determined based on a
characteristic of the uplink control information.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 14/315,044 filed Jun. 25, 2014 by Youn Hyoung
Heo, et al., entitled, "System and Method for Uplink Control
Information Transmission in Carrier Aggregation" (Atty. Docket No.
39014-US-DIV-4214-28507), which is a divisional of U.S. Pat. No.
8,767,647 issued on Jul. 1, 2014 entitled, "System and Method for
Uplink Control Information Transmission in Carrier Aggregation"
(Atty. Docket No. 39014-US-PAT-4214-28501), which claims priority
to U.S. Provisional Patent Application No. 61/356,537 filed Jun.
18, 2010, by Youn Hyoung Heo, et al., entitled, "System and Method
for Uplink Control Information Transmission in Carrier Aggregation"
(Atty. Docket No. 39014-US-PRV-4214-28500), all of which are
incorporated by reference herein as if reproduced in their
entirety.
BACKGROUND
[0002] The present embodiments relate generally to data
transmission in communication systems and, more specifically, to
methods and systems for control information transmission in
networks and devices implementing carrier aggregation.
[0003] As used herein, the terms "user equipment" and "UE" can
refer to wireless devices such as mobile telephones, personal
digital assistants (PDAs), handheld or laptop computers, and
similar devices or other User Agents ("UA") that have
telecommunications capabilities. In some embodiments, a UE may
refer to a mobile, wireless device. The term "UE" may also refer to
devices that have similar capabilities but that are not generally
transportable, such as desktop computers, set-top boxes, or network
nodes.
[0004] In traditional wireless telecommunications systems,
transmission equipment in a base station or other network node
transmits signals throughout a geographical region known as a cell.
As technology has evolved, more advanced equipment has been
introduced that can provide services that were not possible
previously. This advanced equipment might include, for example, an
evolved universal terrestrial radio access network (E-UTRAN) node B
(eNB) rather than a base station or other systems and devices that
are more highly evolved than the equivalent equipment in a
traditional wireless telecommunications system. Such advanced or
next generation equipment may be referred to herein as long-term
evolution (LTE) equipment, and a packet-based network that uses
such equipment can be referred to as an evolved packet system
(EPS). Additional improvements to LTE systems and equipment may
result in an LTE advanced (LTE-A) system. As used herein, the
phrase "base station" will refer to any component or network node,
such as a traditional base station or an LTE or LTE-A base station
(including eNBs), that can provide a UE with access to other
components in a telecommunications system.
[0005] In mobile communication systems such as the E-UTRAN, a base
station provides radio access to one or more UEs. The base station
comprises a packet scheduler for dynamically scheduling downlink
traffic data packet transmissions and allocating uplink traffic
data packet transmission resources among all the UEs communicating
with the base station. The functions of the scheduler include,
among others, dividing the available air interface capacity between
UEs, deciding the transport channel to be used for each UE's packet
data transmissions, and monitoring packet allocation and system
load. The scheduler dynamically allocates resources for Physical
Downlink Shared CHannel (PDSCH) and Physical Uplink Shared CHannel
(PUSCH) data transmissions, and sends scheduling information to the
UEs through a control channel.
[0006] To facilitate communications, a plurality of different
communication channels are established between a base station and a
UE including, among other channels, a Physical Downlink Control
Channel (PDCCH). As the label implies, the PDCCH is a channel that
allows the base station to control a UE during downlink data
communications. To this end, the PDCCH is used to transmit
scheduling assignment or control data packets referred to as
Downlink Control Information (DCI) packets to the a UE to indicate
scheduling to be used by the UE to receive downlink communication
traffic packets on the PDSCH or transmit uplink communication
traffic packets on the PUSCH or a Physical Uplink Control Channel
(PUCCH) or specific instructions to the UE (e.g., power control
commands, an order to perform a random access procedure, or a
semi-persistent scheduling activation or deactivation). A separate
DCI packet may be transmitted by the base station to a UE for each
traffic packet/sub-frame transmission.
[0007] In a wireless communications network, it is generally
desirable to provide high data rate coverage using signals that
have a high Signal to Interference Plus Noise ratio (SINR) for UEs
serviced by a base station. Typically, only those UEs that are
physically close to a base station can operate with a very high
data rate. Also, to provide high data rate coverage over a large
geographical area at a satisfactory SINR, a large number of base
stations are generally required. As the cost of implementing such a
system can be prohibitive, research is being conducted on
alternative techniques to provide wide area, high data rate
service.
[0008] In some cases, carrier aggregation can be used to support
wider transmission bandwidths and increase the potential peak data
rate for communications between a UE, base station and/or other
network components. In carrier aggregation, multiple component
carriers are aggregated and may be allocated in a sub-frame to a UE
as shown in FIG. 1. FIG. 1 shows carrier aggregation in a
communications network where each component carrier has a bandwidth
of 20 MHz and the total system bandwidth is 100 MHz. As
illustrated, the available bandwidth 100 is split into a plurality
of carriers 102. In this configuration, a UE may receive or
transmit on multiple component carriers (up to a total of five
carriers 102 in the example shown in FIG. 1), depending on the UE's
capabilities. In some cases, depending on the network deployment,
each component carrier can have a smaller bandwidth than 20 MHz or
carrier aggregation may occur with carriers 102 located in the same
band and/or carriers 102 located in different bands. For example,
one carrier 102 may be located at 2 GHz and a second aggregated
carrier may be located at 800 MHz.
[0009] In many networks, information describing the state or
condition of one or more of the communication channels established
between a UE and a base station can be used to assist a base
station in efficiently allocating the most effective carrier
resources to a UE. The state information is referred to as channel
state information (CSI) and is associated with a particular channel
or carrier established between the base station and the UE. The CSI
provides information about the observed (by the UE) channel quality
on a downlink carrier back to the base station.
[0010] Generally, the CSI is communicated to the base station
within uplink control information (UCI). In some cases, in addition
to the CSI, UCI contains Hybrid Automatic Repeat reQuest (HARQ)
acknowledgment/negative acknowledgement (ACK/NACK) information in
response to PDSCH transmissions on the downlink. Depending upon the
system implementation, the CSI may include the following data as
channel quality information: Channel Quality Indicator (CQI), Rank
Indication (RI), and/or Precoding Matrix Indication (PMI). For
LTE-A (Rel-10), there may be other types of channel quality
information in addition to the Rel-8 formats listed above.
Generally, the CQI assists the base station with selecting an
appropriate modulation and coding scheme (MCS). The RI provides an
indication as to whether the UE can support one or multiple spatial
multiplexing layers, and the PMI provides information about the
preferred multi-antenna precoding for downlink transmissions.
[0011] In an E-UTRAN Release 8 system, there are generally two
approaches for transmitting UCI in a subframe as illustrated in
FIGS. 2a and 2b. FIGS. 2a and 2b are illustrations of exemplary
physical resource mapping for transmitting UCI within a PUCCH and a
PUSCH resource, respectively. Generally, an RB is formed by a
number of Resource Elements (REs). The REs may be arranged in
twelve frequency columns and fourteen time rows (see FIG. 3, for
example). Accordingly, each RE corresponds to a particular
time/frequency combination. The combination of elements in each
time row can be referred to as a Single Carrier--Frequency Division
Multiple Access (SC-FDMA) symbol. Various types of data can be
communicated in each RE or combination of REs. (In FIGS. 2a and 2b,
elements 101, 103 and 104 each include a combination of REs.)
[0012] FIG. 2a illustrates the subframe configuration for
transmission using the PUCCH and FIG. 2b shows a PUSCH
configuration. Both figures show subframes that include two slots
(Slot 0 and Slot 1) with frequency increasing from the bottom of
the RB to the top. Both figures show a particular subframe n. At
any time, a UE may only transmit UCI on either the PUCCH or PUSCH.
As such, only a single one of the subframe configurations shown in
either FIG. 2a or FIG. 2b can be transmitted by a UE at a
particular time to maintain the single carrier property in
uplink.
[0013] PUCCH resources are generally located at the edge of the
system bandwidth and different frequency resource is used for Slot
0 and Slot 1 to achieve frequency diversity gain. Accordingly, in
FIG. 2a, PUCCH block 101 is located at the top of the RBs, at the
highest system bandwidth, and PUCCH block 103 is located at the
bottom of the RBs, at the lowest system bandwidth. Generally, the
precise PUCCH resource is configured or implicitly mapped using the
PDCCH call control element (CCE) index. Both PUCCH resources 101
and 103 can be used to transmit UCI in the available PUCCH
resources as long as the UE does not transmit using the PUSCH
configuration (see FIG. 2b) in the same subframe.
[0014] Referring to FIG. 2b, if the UE is transmitting using the
PUSCH in subframe n, the UCI information may be transmitted within
the PUSCH. As shown in FIG. 2b, PUSCH 104 may occupy a central
region of the available system bandwidth, with the UCI being
included within PUSCH 104.
[0015] When transmitting the UCI within the PUSCH, the UCI is
multiplexed into the uplink-shared channel (UL-SCH). FIG. 3 is an
illustration of an exemplary multiplexing of UCI into the UL-SCH
assuming an RB is scheduled for the PUSCH. As seen in FIG. 3, the
coded CQI/PMI bits 110 can be located at the beginning of the
available PUSCH resources before interleaving. To avoid data
puncturing due to CQI or PMI transmission, the UL-SCH data is
rate-matched to be transmitted with the remaining resources. The
coded ACK/NACK bits 112 can be multiplexed with the UL-SCH data in
the channel interleaver by puncturing symbols of the UL-SCH data.
The location of HARQ ACK/NACK symbols 112 is generally next to the
SC-FDMA symbols used as reference signals (RS) 114 to achieve the
best channel estimation for HARQ ACK/NACK bits 112. Rank indication
(RI) bits 116 can be located next to the HARQ ACK/NACK symbols in
the time dimension, but unlike ACK/NACK, the UL-SCH data may be
rate-matched to accommodate RI resources 116.
[0016] Generally, in a PUSCH transmission, the number of coded
symbols for HARQ-ACK and RI is calculated using the following
equation (1) (see, for example, TS 36.212 Section 5.2.4.1 "3.sup.rd
Generation Partnership Project; Technical Specification Group Radio
Access Network; Evolved Universal Terrestrial Radio Access
(E-UTRA); Multiplexing and channel coding (Release 8)":
Equation ( 1 ) ##EQU00001## Q ' = min ( O M sc PUSCH - initial N
symb PUSCH - initial .beta. offset PUSCH r = 0 C - 1 K r , 4 M sc
PUSCH ) ##EQU00001.2##
[0017] In equation (1), O is the number of ACK/NACK bits or rank
indicator bits, M.sub.sc.sup.PUSCH is the scheduled bandwidth for
PUSCH transmission in the current sub-frame for the transport block
(expressed as a number of subcarriers in TS 36.211, "3rd Generation
Partnership Project; Technical Specification Group Radio Access
Network; Evolved Universal Terrestrial Radio Access (E-UTRA);
Physical channels and modulation (Release 8)"),
.beta..sub.offset.sup.PUSCH is an amplitude scaling factor for the
PUSCH, and N.sub.symb.sup.PUSCH-initial is the number of SC-FDMA
symbols per subframe for initial PUSCH transmission for the same
transport block given by
N.sub.symb.sup.PUSCH-initial=(2(N.sub.symb.sup.UL-1)-N.sub.SRS),
where N.sub.SRS is equal to 1 if the UE is configured to send PUSCH
and SRS in the same subframe for initial transmission or if the
PUSCH resource allocation for initial transmission overlaps, even
partially, with the cell specific SRS subframe and bandwidth
configuration defined in Section 5.5.3 of TS 36.211, "3rd
Generation Partnership Project; Technical Specification Group Radio
Access Network; Evolved Universal Terrestrial Radio Access
(E-UTRA); Physical channels and modulation (Release 8)". Otherwise
N.sub.SRS is equal to 0. M.sub.sc.sup.PUSCH-initial, C, and K.sub.r
can be obtained from the initial PDCCH for the same transport
block. Accordingly, equation (1) defines a minimum number of HARQ
ACK/NACK bits to be encoded within a PUSCH subframe.
[0018] Generally, the actual number of coded symbols for channel
quality information (CQI and/or PMI) can be determined using
equation (2) (see, for example, TS 36.212 in Section 5.2.4.1
"3.sup.rd Generation Partnership Project; Technical Specification
Group Radio Access Network; Evolved Universal Terrestrial Radio
Access (E-UTRA); Multiplexing and channel coding (Release 8)"):
Equation ( 2 ) ##EQU00002## Q ' = min ( ( O + L ) M sc PUSCH -
initial N symb PUSCH - initial .beta. offset PUSCH r = 0 C - 1 K r
, M sc PUSCH N symb PUSCH - Q RI Q m ) ##EQU00002.2##
[0019] In equation (2), O is the number of CQI bits, L is the
number of cyclic redundancy check (CRC) bits given by
L = { 0 O .ltoreq. 11 8 otherwise , ##EQU00003##
Q.sub.CQI=Q.sub.mQ' and
[.beta..sub.offset.sup.PUSCH=.beta..sub.offset.sup.CQI],
respectively, where .beta..sub.offset.sup.CQI may be determined
according to TS 36.213, "3rd Generation Partnership Project;
Technical Specification Group Radio Access Network; Evolved
Universal Terrestrial Radio Access (E-UTRA); Physical layer
procedures (Release 8)". If a rank indicator is not transmitted,
then Q.sub.RI=0. M.sub.sc.sup.PUSCH-initial, C, and K.sub.r can be
obtained from the initial PDCCH for the same transport block.
[0020] In E-UTRAN Release 8 systems, multiple applications
supported in a UE can have different quality of service (QoS)
requirements. For example, VoIP service may require a smaller delay
requirement, while file transfer protocol (FTP) applications may be
more tolerant of delays. To support different QoS, different radio
bearers may be configured and each bearer may be associated with a
particular QoS.
[0021] On the uplink channels, each radio bearer maps onto a
separate logical channel. FIG. 4 is an illustration showing the
mapping from various uplink radio bearers, to uplink logical
channels, to uplink transport channels, and, finally, to uplink
physical channels. Referring to FIG. 4, Signaling Radio Bearers
(SRBs) 150 can carry control-plane signaling messages. For example,
SRB0 may correspond to the Common Control CHannel (CCCH) that is
used only when a UE does not have a regular connection with a DCCH
(Dedicated Control CHannel). The other two SRBs 150 may map to
separate DCCHs after a connection has been established, for
example. SRB1 can be used to carry control-plane messages
originating from radio resource configuration (RRC), and SRB2 can
used to carry encapsulated control-plane messages originating from
the non-access stratum (NAS). Data Radio Bearers (DRBs) 152 can
carry user-plane traffic. A separate Dedicated Traffic CHannel
(DTCH) may be set up for each active DRB.
[0022] In FIG. 4, each of the uplink logical channels map to the
UL-SCH 154 at the transport channel level, which in turn maps to
the PUSCH 156 at the physical channel level. Separately, the Random
Access CHannel (RACH) 158 transport channel maps to the Physical
RACH (PRACH) 160 for performing random accesses, and the PUCCH
physical channel 162 carries physical layer signaling to the base
station.
[0023] Additionally, the UE may transmit medium access control
(MAC) control elements (MAC CE) on the uplink channel to
communicate control signaling to the base station. MAC control
elements can be short (e.g., a few bytes) signaling messages that
are included within a MAC Protocol Data Unit (PDU) that is
transmitted on the uplink to the base station. For example, Rel-8
MAC control elements may include a Cell Radio Network Temporary
Identifier (C-RNTI) MAC CE, a Buffer Status Report (BSR) MAC CE,
and a Power Headroom Report (PHR) MAC CE.
[0024] MAC CEs (if appropriate) may first be scheduled into any new
uplink transmission allocation. Generally, MAC CEs have a higher
priority than logical channel traffic (e.g., from a DCCH or DTCH),
with the exception of a Padding BSR. UL-CCCH traffic (e.g., from
SRB0) may also have higher priority than MAC control elements.
[0025] In Release 8, UCI can be transmitted on either the PUCCH or
PUSCH depending on whether PUSCH resources for UL-SCH transmission
are scheduled and available. In newer network implementations
providing carrier aggregation, however, a UE may be scheduled to
transmit PUSCH on multiple uplink carriers simultaneously to
increase the peak data rate. In some network implementations,
however, only a single carrier may be allocated for UCI
transmissions within the PUCCH from a UE. In that case, a single
UE-specific UL component carrier (CC) is configured semi-statically
for carrying PUCCH UCI from a UE. In such an implementation, only
one UL CC is configured to transmit PUCCH for UCI transmission even
though multiple UL CCs are configured to transmit data with PUSCHs.
This may reduce UE battery power consumption by turning on only a
single carrier for control signaling. In addition, it may be
beneficial to reduce the control signaling overhead because only a
single transmit power control (TPC) command is sufficient to
control PUCCH power.
[0026] In some cases, simultaneous transmission of UCI and data may
also be supported in a network. In that case, UCI may be
transmitted on the PUCCH along with PUSCH for data transmission. In
such an implementation, the single carrier property can be relaxed
with the introduction of clustered Discrete Fourier
Transform--Spread Orthogonal Frequency Division Multiplexing
(DFT-S-OFDM), for example. In such an implementation, however,
simultaneous transmission of PUCCH and PUSCH may cause larger radio
emissions due to the inter-modulation between PUCCH and PUSCH
especially within a carrier --it is likely that the transmit power
difference between PUCCH and PUSCH is relatively large due to the
different data rates.
[0027] Generally, in newer networks, the payload of UCI is expected
to be larger than that of Release 8 because LTE-A UEs may support
DL transmission on multiple DL carriers because CQI/PMI/RI feedback
for each of the available carriers will be communicated to the base
station by the UE and HARQ ACK-NACK feedback for each of the
scheduled carriers will be required. As such, the payload of UCI
could increase linearly with the number of active DL carriers. For
example, in Release 8, the number of HARQ-ACK bits is generally 1
bit or 2 bits for Frequency Division Duplexing (FDD) and 1-4 bits
for Time Division Duplexing (TDD). Table 1 shows the required bits
for HARQ-ACK data depending upon the number of scheduled downlink
carriers and the number of code words. The values are calculated
assuming ACK, NACK and DTX indications are required for each
carrier because PDCCHs are separately transmitted to schedule PDSCH
on multiple carriers. In the case of two code words, five
indication values are required as ACK/NACK for first codeword,
ACK/NACK for second codeword and DTX for PDCCH misdetection. That
is, the UE needs to be able to signal the following five different
states for the case of two code words (A=ACK, N=NACK): (A,A),
(A,N), (N,A), (N,N), and DTX. As shown in Table 1, as the number of
carriers increases, so does the numbers of bits required for each
codeword, whether the codeword is a double or single codeword.
TABLE-US-00001 TABLE 1 Number of carriers 2 3 4 5 Two code words
.left brkt-top.log.sub.2 5.sup.N - 1.right brkt-bot. 5 7 10 12
Single codeword .left brkt-top.log.sub.2 3.sup.N - 1.right
brkt-bot. 3 5 7 8
[0028] A result of an increase in UCI data to be transmitted by the
UE is to reduce the available UL-SCH resources for data
transmission due to rate matching or puncturing in a transmission.
This is particularly true for HARQ-ACK transmissions, where
puncturing may be prevalent. To minimize the reduction of the
available UL-SCH resources due to the UCI, the base station can
increase the PUSCH resources. If, for example, UCI is transmitted
within the PUSCH and the PUSCH resource is dynamically scheduled
for the initial transmission the PUSCH resources can be increased
to accommodate the resources for the UCI transmission. However, if
UCI needs to be transmitted within the PUSCH for the
re-transmission of UL-SCH data or semi-persistently scheduled PUSCH
resources, it may be difficult to increase the PUSCH resources. In
this case, it may be necessary to retransmit the data because the
transmission with the UCI may not be successfully received due to
the puncturing losses caused by the UCI transmission. The increased
number of transmissions may not be detrimental if the data is not
delay-sensitive, e.g., FTP or TCP IP data. But the increased number
of transmissions may negatively affect the performance of
delay-sensitive data, e.g., VoIP or MAC signaling (e.g., MAC
control element), or RRC signaling messages that include
measurement reports, or other high priority data traffic.
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] For a more complete understanding of this disclosure,
reference is now made to the following brief description, taken in
connection with the accompanying drawings and detailed description,
wherein like reference numerals represent like parts.
[0030] FIG. 1 shows carrier aggregation in a communications network
where each component carrier has a bandwidth of 20 MHz and the
total system bandwidth is 100 MHz;
[0031] FIGS. 2a and 2b are illustrations of exemplary physical
resource mapping for transmitting UCI within a PUCCH and a PUSCH,
respectively;
[0032] FIG. 3 is an illustration of an exemplary multiplexing of
UCI data into the UL-SCH showing an RB containing REs;
[0033] FIG. 4 is an illustration showing the mapping from various
uplink radio bearers, to uplink logical channels, to uplink
transport channels, and, finally, to uplink physical channels;
[0034] FIGS. 5a, 5b, and 5c are illustrations of exemplary
collections of CCs allocated to a particular UE and showing how the
UE is configured to select particular CCs of the set of available
CCs for UCI transmissions;
[0035] FIG. 6 illustrates steps in a method for the UE to select
one or more UL CCs for UCI transmission;
[0036] FIG. 7 is an illustration of an example subframe showing
candidate locations for an increased number of HARQ-ACK
symbols;
[0037] FIG. 7A is an illustration of an example subframe showing
UCI transmission in clustered DFT-S-OFDM, in which two clusters are
allocated for PUSCH transmission and ACK/NACK or RI may be
distributed over the two clusters;
[0038] FIG. 8 is a diagram of a wireless communications system
including a UE operable for some of the various embodiments of the
disclosure;
[0039] FIG. 9 is a block diagram of a UE operable for some of the
various embodiments of the disclosure;
[0040] FIG. 10 is a diagram of a software environment that may be
implemented on a UE operable for some of the various embodiments of
the disclosure; and
[0041] FIG. 11 is an illustrative general purpose computer system
suitable for some of the various embodiments of the disclosure.
DETAILED DESCRIPTION
[0042] The present embodiments relate generally to data
transmission in communication systems and, more specifically, to
methods and systems for control information transmission in
networks and devices implementing carrier aggregation.
[0043] Some embodiments include a method for communicating uplink
control information to a base station using a user equipment. The
method includes identifying component carriers on the user
equipment scheduled for Physical Uplink Shared CHannel (PUSCH)
transmissions, and identifying at least one first ranking for each
of the component carriers for transmission of uplink control
information. Each first ranking is at least partially determined by
whether the component carrier is configured for delay-sensitive
transmissions. The method includes using the at least one first
ranking to select a first component carrier for transmission of
uplink control information, and encoding uplink control information
into the first component carrier for transmission to the base
station.
[0044] Other embodiments include a method for communicating uplink
control information to a base station using a user equipment. The
method includes identifying component carriers on the user
equipment scheduled for Physical Uplink Shared CHannel (PUSCH)
transmissions. When one or more of the component carriers is
configured for non-delay-sensitive transmissions, the method
includes identifying one or more of the component carriers that are
configured for non-delay-sensitive transmissions, and selecting a
first component carrier from the one or more of the component
carriers for transmission of uplink control information. The method
includes encoding uplink control information into the first
component carrier for transmission to the base station.
[0045] Other embodiments include a method for allocating Hybrid
Automatic Repeat reQuest (HARQ)
acknowledgement/negative-acknowledgement (HARQ ACK/NACK) symbols on
a physical uplink shared channel (PUSCH). The method includes
identifying a first number of allocated symbols for HARQ ACK/NACK
transmission within a PUSCH subframe. The method includes, when
implementing carrier aggregation, increasing a number of allocated
symbols for HARQ ACK/NACK transmission, and using the increased
number of allocated symbols to transmit HARQ ACK/NACK data within
the PUSCH subframe.
[0046] Other embodiments include a method for communicating uplink
control information to a base station using a user equipment. The
method includes determining a puncturing ratio of a first physical
uplink shared channel (PUSCH) subframe. The puncturing ratio
identifies a ratio of symbols in the PUSCH subframe allocated for
uplink control information to symbols in the PUSCH subframe
allocated for uplink shared channel (UL-SCH) data. When the
puncturing ratio is greater than a threshold, the method includes
reducing an amount of uplink shared channel (UL-SCH) data encoded
in the PUSCH subframe.
[0047] Other embodiments include a user equipment including a
processor configured to identify component carriers on the user
equipment scheduled for Physical Uplink Shared CHannel (PUSCH)
transmissions, and identify at least one first ranking for each of
the component carriers for transmission of uplink control
information. Each first ranking is at least partially determined by
whether the component carrier is configured for delay-sensitive
transmissions. The processor is configured to use the at least one
first ranking to select a first component carrier for transmission
of uplink control information, and encode uplink control
information into the first component carrier for transmission to a
base station.
[0048] Other embodiments include a user equipment including a
processor configured to identify component carriers on the user
equipment scheduled for Physical Uplink Shared CHannel (PUSCH)
transmissions. When one or more of the component carriers is
configured for non-delay-sensitive transmissions, the processor is
configured to identify one or more of the component carriers that
are configured for non-delay-sensitive transmissions, and select a
first component carrier from the one or more of the component
carriers for transmission of uplink control information. The
processor is configured to encode uplink control information into
the first component carrier for transmission to a base station.
[0049] To the accomplishment of the foregoing and related ends, the
invention, then, comprises the features hereinafter fully
described. The following description and the annexed drawings set
forth in detail certain illustrative aspects of the invention.
However, these aspects are indicative of but a few of the various
ways in which the principles of the invention can be employed.
Other aspects and novel features of the invention will become
apparent from the following detailed description of the invention
when considered in conjunction with the drawings.
[0050] The various aspects of the subject invention are now
described with reference to the annexed drawings, wherein like
numerals refer to like or corresponding elements throughout. It
should be understood, however, that the drawings and detailed
description relating thereto are not intended to limit the claimed
subject matter to the particular form disclosed. Rather, the
intention is to cover all modifications, equivalents, and
alternatives falling within the spirit and scope of the claimed
subject matter.
[0051] As used herein, the terms "component," "system" and the like
are intended to refer to a computer-related entity, either
hardware, a combination of hardware and software, software, or
software in execution. For example, a component may be, but is not
limited to being, a process running on a processor, a processor, an
object, an executable, a thread of execution, a program, and/or a
computer. By way of illustration, both an application running on a
computer and the computer can be a component. One or more
components may reside within a process and/or thread of execution
and a component may be localized on one computer and/or distributed
between two or more computers.
[0052] The word "exemplary" is used herein to mean serving as an
example, instance, or illustration. Any aspect or design described
herein as "exemplary" is not necessarily to be construed as
preferred or advantageous over other aspects or designs.
[0053] Furthermore, the disclosed subject matter may be implemented
as a system, method, apparatus, or article of manufacture using
standard programming and/or engineering techniques to produce
software, firmware, hardware, or any combination thereof to control
a computer or processor based device to implement aspects detailed
herein. The term "article of manufacture" (or alternatively,
"computer program product") as used herein is intended to encompass
a computer program accessible from any computer-readable device,
carrier, or media. For example, computer readable media can include
but are not limited to magnetic storage devices (e.g., hard disk,
floppy disk, magnetic strips . . . ), optical disks (e.g., compact
disk (CD), digital versatile disk (DVD) . . . ), smart cards, and
flash memory devices (e.g., card, stick). Additionally it should be
appreciated that a carrier wave can be employed to carry
computer-readable electronic data such as those used in
transmitting and receiving electronic mail or in accessing a
network such as the Internet or a local area network (LAN). Of
course, those skilled in the art will recognize many modifications
may be made to this configuration without departing from the scope
or spirit of the claimed subject matter.
[0054] In LTE-A, a UE can transmit UL data over multiple UL CCs
dependent upon base station configuration and UE capability. For
each UE, a number of available UL CCs can be configured when the UE
is connected to a base station. The PUSCH resources that occur
within each of the available CCs can then be allocated by UL grants
dynamically transmitted by the base station to the UE or through a
semi-persistent scheduling (SPS) allocation similar to Release
8.
[0055] When multiple UL CCs are allocated to a UE in a subframe and
UCI needs to be transmitted, the UCI may be transmitted using any
of the scheduled CCs. Although any of the available UL CCs (e.g.,
UCI for each UL CC is transmitted to the base station using that
particular CC) may be used, it is not generally desirable to do so
if the UL CCs transmit data using different QoS settings. Differing
QoS results in varying levels of puncture loss in each
transmission. If a particular CC is used to transmit
delay-sensitive data, by transmitting UCI using that CC,
significant puncturing may result. It is important to avoid
puncturing losses in delay-sensitive communications, however, as
the losses can result in delay due to data re-transmission
resulting from the puncturing. Accordingly, it may be preferable to
transmit UCI using particular ones of the available UL CCs that are
configured to carry non-delay-sensitive data.
[0056] In the present system, a UE is configured to transmit UCI
using CCs that do not carry delay-sensitive data when multiple UL
CCs are allocated to transmit PUSCHs. As such, the UE can avoid
transmitting UCI using CCs that are configured for high-QoS
communications. In one implementation, delay-sensitive
transmissions include 1) those using resources allocated by
semi-persistent scheduling (SPS), 2) Signaling Radio Bearer (SRB)
transmissions, e.g., SRB1, 3) MAC CE transmissions, and 4) other
high priority traffic. Generally, therefore, the UE avoids using
CCs that require low delay, such as CCs transmitting data with a
particular CQI index. For example, the UE may avoid CCs, as defined
in the TS 23.203 v 8.9.0, that have a CQI index of 3 for which the
delay budget is 50 ms.
[0057] As an example, FIGS. 5a, 5b, and 5c are illustrations of
exemplary collections of CCs allocated to a particular UE and
showing how the UE is configured to select particular CCs of the
set of available CCs for UCI transmissions. In FIG. 5a, two
carriers, CC1 and CC3, are activated on the UE and are scheduled to
transmit PUSCH1 and PUSCH2, respectively. Either PUSCH1 or PUSCH2
can be used for the transmission of UCI, but PUSCH1 is allocated
for SPS while PUSCH2 is allocated by dynamic grant. Therefore,
there is a high likelihood that the SPS resources will be used to
transmit data requiring a semi-static data rate (e.g., VoIP) and
requiring minimal delay (i.e., delay-sensitive communications). As
such, in the present system, the UE is configured avoid
transmitting the UCI using PUSCH1. Instead, the UE transmits the
UCI using PUSCH2. Although the inclusion of UCI in PUSCH2 may
result in puncturing of data included within PUSCH2, because PUSCH2
is less likely than PUSCH1 to transmit delay-sensitive data (PUSCH2
is not allocated for SPS), a re-transmission of the PUSCH2 data is
more acceptable than a retransmission of the PUSCH1 data.
[0058] In FIG. 5b three carriers, CC1, CC3, and CC4, are allocated
to the UE and are scheduled to transmit PUSCH1, PUSCH2 and PUSCH3,
respectively. PUSCH1 is allocated for SPS, while PUSCH2 and PUSCH3
are both allocated by dynamic grant. Generally, there is a high
likelihood that the SPS resource will be used to transmit data
requiring a semi-static data rate (e.g., VoIP) and with tight delay
requirements. Accordingly, the UE is configured to avoid
retransmissions of PUSCH1. Similarly, as PUSCH2 transmits SRB which
need to be delivered without delay, the UE is configured to avoid
retransmissions of PUSCH2. Accordingly, in the present system, the
UE is configured to transmit the UCI in PUSCH3 which is allocated
by dynamic grant and, in this example, is configured to transmit
DRBs.
[0059] In FIG. 5c, four carriers, CC1, CC3, CC4, and CC5, are
allocated to the UE and scheduled to transmit PUSCH1, PUSCH2,
PUSCH3 and PUSCH4, respectively. PUSCH1 is allocated for SPS, while
PUSCH2 and PUSCH3 are both allocated by dynamic grant. Generally,
there is a high likelihood that the SPS resource will be used to
transmit data requiring a semi-static data rate (e.g., VoIP) and
with stringent delay requirements. Accordingly, the UE is
configured to avoid retransmissions of PUSCH1. Similarly, as PUSCH2
transmits SRB which need to be delivered without delays, the UE is
configured to avoid retransmissions of PUSCH2. PUSCH3 and PUSCH4
are both allocated by dynamic grant and, therefore, may carry
communications more tolerant of delay. In this example, because
there are two UL CCs allocated by dynamic grant and used to
transmit normal DRBs, the UE is configured to transmit UCI in
either PUSCH3 or PUSCH4. For example, the UE may select a single
one of PUSCH3 and PUSCH4 for the transmission of UCI (in FIG. 5c,
the UCI is only transmitted in PUSCH4). Alternatively, the UCI can
be distributed across both PUSCH3 and PUSCH4.
[0060] When only a single PUSCH carrier is allocated to the UE and
is available for UCI transmission, puncturing losses may be
unavoidable. If the puncturing loss is severe and happens often,
the base station may consider other ways to reduce the HARQ delay.
For example, a more conservative MCS can be selected for the
low-delay-requirement data. A conservative MCS, however, may
require additional radio resources to achieve the same information
bit rate. Therefore, it would not be efficient in terms of resource
utilization given that UCI is not always transmitted whenever PUSCH
is transmitted. That is, when UCI is not transmitted, a
non-punctured PUSCH transmission with an overly conservative MCS
would represent an inefficient use of the cell's uplink radio
resources that could have otherwise been assigned to other UEs.
[0061] In some cases, the base station indicates a carrier ranking
to the UE allowing the UE to select the most appropriate CC for UCI
transmissions. The ranking may define which CC has a higher
priority for UCI transmission when multiple carriers are scheduled
for PUSCH transmission. To minimize the problems described above,
for example, CCs that are used for delay-sensitive data will be
allocated a priority that prevents (or minimizes) UCI transmission
on those CCs. Assuming the base station is aware of which CCs, if
any, transmit SPS and which CCs transmit SRB, the base station can
generate a priority listing minimizing the transmission of UCI
using the SPS CCs. The carrier ranking information can then be
signaled by higher layer or L1/2 signaling (e.g., MAC CE) to the
UE, for example.
[0062] Table 2 shows example carrier ranking information for UCI
transmissions. In Table 2, each carrier is assigned different
ranking values for each of three different example configurations.
In this implementation, a lower ranking value means the CC is more
likely to be selected for transmitting UCI, but other ranking
orderings may be used. Therefore, when multiple CCs are allocated,
the UE first selects a carrier having the lower ranking value in
order to transmit UCI. If that carrier is unavailable, the UE can
then select an alternative carrier with the next higher (or the
same) priority.
[0063] In one example, a UE is allocated CC1 and CC3 (see, for
example, FIG. 5a) for UCI transmissions and selects a CC for UCI
based upon Configuration 1 of Table 2. In Configuration 1, CC3 has
a lower ranking than CC1 (a value of 3 versus 4, respectively).
Accordingly, the UE is configured to select CC3 for UCI
transmission initially.
[0064] In another example, a UE is allocated CC1, CC3, CC4, and CC5
(see, for example, FIG. 5c) for UCI transmissions and selects a CC
for UCI based upon Configuration 1 of Table 2. In Configuration 1,
the UE will select CC4 for UCI transmission because CC4 has the
lowest ranking for UCI transmission among the other scheduled (and
allowed) CCs (i.e., CC1, CC3, CC4 and CC5).
TABLE-US-00002 TABLE 2 Configuration 1 Configuration 2
Configuration 3 CC1 4 3 Not Allowed CC2 5 3 Not Allowed CC3 3 2 3
CC4 1 1 1 CC5 2 1 2
[0065] In some cases, the same ranking can be defined for different
CCs (see, for example, CC1 and CC2 in Configuration 2 of Table 2 as
well as CC4 and CC5 in Configuration 2). When two CCs are assigned
the same ranking, the UE may be configured to use either CC to
transmit UCI based upon a predefined rule or algorithm, or transmit
the UCI on both carriers. The predefined rule or algorithm can be
based on the CC index value, for example. When multiple CCs of the
same priority ranking are scheduled, the UE can select the CC with
the lowest (or highest) CC index to transmit UCI.
[0066] Alternatively, the ranking value may not be available for
some CCs or the CCs may be unauthorized for transmission of UCI
(see, for example, CC1 and CC2 of Configuration 3 of Table 2). If a
CC is not allocated a ranking value, that may indicate that UCI
transmission in that particular PUSCH is banned. In that case, when
the only scheduled carriers are not allocated rankings (e.g.,
carriers CC1 and CC2 in configuration 3 of Table 2), the UE may
drop UCI transmission or transmit using the PUCCH resource
only.
[0067] The present carrier ranking can also be defined via an
implicit method without any extra over-the-air signaling. For
example, carriers could be ranked in ascending or descending order
by other parameters, e.g., carrier frequency, system bandwidths,
scheduled number of RBs, transport block size, MCS level, etc.
Sequential ranking according to the CC index or linked to other CC
parameters may also be used to rank the CCs. Furthermore, the
ranking may be implicitly defined by the received UL grants.
[0068] The present carrier ranking may also be used to define
different carrier rankings for each of the UL-SCH data types
available on each carrier. As an example, Table 3 shows an example
carrier ranking for SRB transmission and MAC CE transmission. In
this example, the CC rankings for the CCs when transmitting SRB or
MAC CE are almost the reverse order of the CC rankings when
transmitting UCI.
TABLE-US-00003 TABLE 3 SRB MAC CEs UCI CC1 5 5 4 CC2 2 1 5 CC3 1 2
3 CC4 4 4 1 CC5 3 3 2
[0069] Depending upon the system implementation, the base station
may only signal rankings to the UE for one or more of the UL-SCH
data types. For example, the base station may only signal the
carrier ranking for SRB and MAC CE to the UE. Then, based upon the
rankings for SRB and MAC CE, the carrier ranking for UCI is then
implicitly derived, for example, based on reverse order of the
carrier ranking of SRB/MAC CE, for example, by subtracting each
priority ranking from the maximum priority value. For example, if
the ranking for SRB or MAC CE for a first CC is 2, and the maximum
possible ranking value is 5, the ranking for UCI would be 5-2 or
3.
[0070] In some cases, the radio conditions of different CCs may
also be considered by the UE for scheduling. For example, for the
SRB transmissions, if CC3 has poor radio conditions at a particular
time, while at the same time, CC1 has better radio conditions, the
UE may be configured to use CC1 for SRB transmissions. Therefore,
Table 3 may be used by the UE only for relative preferential
selection of CC for SRB traffic. Since a logical channel ID may be
included for each MAC SDU contained within a MAC PDU, the MAC
entity at the base station may be able to correctly extract SRB
traffic from whichever MAC PDU(s) the UE placed the SRB message(s)
into, with no increase in complexity for the base station.
[0071] When the UE is scheduled to transmit simultaneously on
multiple uplink carriers, there may be a separate MAC PDU for each
scheduled carrier. The UE may take into consideration the radio
condition of the scheduled CCs and the carrier ranking for sending
UCI when selecting upon which CC to transmit SRB. Generally, the CC
chosen to transmit SRB is different from the CC chosen to transmit
UCI based on the UCI carrier-ranking rule instructed by the base
station and should have the best radio condition among the
scheduled CCs.
[0072] In some cases, if the CC transmitting UCI is variable
depending on channel situation, the base station may have to
perform blind decoding to know which UL CC includes UCI.
Alternatively, if the scheduled MCS or the amount of frequency
resources consumed is used as one way of considering the radio
condition, the base station and the UE are generally aware of UL CC
for UCI exactly and, therefore, blind decoding for UCI may not be
needed.
[0073] The carrier ranking tables shown in Table 2 and Table 3 are
only examples. The carrier ranking could be updated with rules that
use other factors. For example, when the number of configured CCs
changes, the carrier ranking could be updated and signaled to the
UE. This carrier ranking could be carried in the RRC message
reconfiguring the carriers, or in a MAC control element (possibly
the same MAC control element as is used to activate or deactivate
specific carriers). Alternatively, when a UL CC is added to the
configured set of UL CCs of a UE via signaling such as RRC
signaling, the carrier ranking of the newly added CC may also be
provided in the RRC signaling.
[0074] Alternatively, the carrier ranking of UCI is configured,
while the carrier ranking of delay-sensitive data is not
configured. In this case, the UE can select UL CCs transmitting
delay-sensitive data as UL CCs not transmitting UCI. For example,
when CC1, CC4 and CC5 are scheduled, the UE selects CC4 for UCI
transmission if the carrier ranking is configured the same as
Configuration 1 in Table 2. The UE can select one of CC1 and CC5 to
transmit delay-sensitive data. Among all the scheduled UL CCs not
transmitting UCI, the UL CC used to transmit MAC CE can be selected
based on a predefined rule, using parameters such as the order of
carrier index, MCS or bandwidth.
[0075] In another implementation, the carrier ranking of UCI is
configured, while the carrier ranking of delay-sensitive data is
not configured. In that case, the granted resources of the
scheduled UL CCs may be ordered such that the resources of the UL
CC selected for UCI transmission are placed last or placed such
that it is not the first scheduled UL CC in the order. The UE may
then perform logical channel and MAC CE prioritization on the
ordered UL resources across the scheduled UL CCs when deciding how
to map the logical channel traffic and MAC CE on to the scheduled
UL CCs. For example, when CC1, CC4 and CC5 are scheduled, the UE
selects CC4 for UCI transmission if the carrier ranking is
configured the same as Configuration 1 in Table 2. The UE orders
the granted resources of these three scheduled CCs such that UL
resources of CC4 are placed last. For example, the granted UL
resources may be ordered as follows: resources for CC1, followed by
resources for CC5, followed by resources for CC4, such that the UE
performs logical channel and MAC CE prioritization following this
order when mapping the logical channel traffic and MAC CE to the
resources across the scheduled UL CCs.
[0076] As another embodiment to the carrier ranking procedures
described above, in order to avoid a relatively large puncturing
loss, if a UL CC is scheduled with a smaller number of physical
resource blocks (PRBs) than a certain PRB threshold, then that UL
CC could be precluded from transmitting UCI. In some embodiments,
the UL CC may be precluded from transmitting UCI even if the UL CC
has a higher ranking for transmitting UCI relative to other UL CCs.
In other words, the UCI might not be transmitted on a UL CC.
Instead, the next available UL CC with the highest carrier ranking
might be used to transmit UCI. The PRB threshold may be pre-defined
or configured by higher layer signaling. In an embodiment,
different PRB thresholds may be configured for each UL CC.
[0077] In the case of using a predefined PRB threshold, because the
UCI size could vary depending on the number of scheduled DL CCs or
activated DL CCs, the PRB threshold may be defined with respect to
the actual UCI transmission. Several alternatives exist with
respect to defining the PRB threshold with respect to the actual
UCI transmission.
[0078] In one alternative, the PRB threshold may be decided based
on the number of coded symbols required or desired for UCI. For a
relatively small number of coded symbols required or desired for
UCI, a small number of PRBs may be defined as the PRB
threshold.
[0079] In another alternative, the PRB threshold may be decided
based on the number of DL CCs requiring UCI, with respect to active
DL CCs or configured DL CCs. Because UCI information may be defined
per DL CC, the overall size of a UCI transmission might be linearly
dependent on the number of DL CCs requiring UCI. Because UCI with a
small number of DL CCs could cause a small puncturing loss, the PRB
threshold may be lower relative to the case when a larger number of
DL CCs is activated or configured. Thus, an embodiment for deciding
the PRB threshold may be to define an averaged PRB threshold on a
per CC basis. The total PRB threshold could be a linear scaling of
this average PRB threshold.
[0080] In still another alternative, the PRB threshold is decided
based on the characteristic of UCI transmission. For example, the
PRB threshold for HARQ ACK/NACK may be defined differently from the
threshold used for CQI/PMURI.
[0081] As another embodiment to the carrier ranking procedures
described above, a certain UL CC could be precluded from being used
as a UCI CC based on the configured transmission mode of the UL CC,
even if that UL CC has a higher ranking for transmitting UCI. For
example, if a UL CC is configured with a single antenna port mode,
this UL CC could be precluded from transmitting UCI because the
puncturing loss might be more significant compared to UL CCs
configured to use a multiple antenna port transmission mode (where
up to two transport blocks could be transmitted). Such preclusion
could be temporary based on the currently configured transmission
mode.
[0082] In all of the above cases, the same rule for selecting the
UCI CC might be applied at both the UE transmitter and the base
station receiver. Thus, for this embodiment, the base station may
know on which UL CC to expect a particular UCI transmission.
[0083] In some implementations, the UE selects the most appropriate
CC for UCI transmission using an implicit algorithm. The algorithm
is based upon the following information of which the UE is aware.
First, the UE knows which CC is configured to support SPS. As one
UL CC will be used for SPS when the configuration related to SPS is
signaled, the UE should be signaled with UL CC information for SPS.
The exact carrier information may be signaled, or, alternatively,
it is also possible for the UL SPS transmissions to occur on the
same UL CC as the UL CC that transmits PUCCH.
[0084] Second, the UE knows the carrier ordering or rankings for
SRB transmissions. There are a number of possible approaches for
indicating to the UE the carrier(s) allocated for transmitting SRB
data. One approach is to explicitly signal the carrier ordering
(e.g., using a carrier-ranking table such as Table 3 above). The
other approach is to implicitly determine a logical channel
priority ordering based upon a predetermined algorithm. In this
approach, each carrier may have a different priority for logical
channels. Carrier ordering for SRB transmission can be decided by
referring to the logical channel priority corresponding to the SRB
logical channels.
[0085] Third, the UE knows a carrier order for MAC CE transmission.
In a similar manner as for SRB transmissions, the UE may know the
carrier order for MAC CE transmission by explicit signaling from
the base station. Alternatively, the carrier order may be
determined based upon a predetermined algorithm.
[0086] Fourth, the UE knows of a carrier to be used for other
low-delay data transmission (e.g., linked via the QCI index). The
UE may be aware of the QCI index of the logical channel and, hence,
can determine which CC is preferred for the transmission of UCI.
The QCI may be signaled by higher layer signaling.
[0087] Given this information, FIG. 6 illustrates steps in a method
for the UE to select one or more UL CCs for UCI transmission. In
step 200, the UE checks whether multiple UL CCs have been
scheduled. If only a single PUSCH CC is scheduled, the UE selects
that UL CC in step 201 and transmits UCI using that UL CC in step
202 as there is no other PUSCH CC to select. If only a single PUSCH
CC is scheduled and this CC is used to transmit SPS or other high
QoS RBs, the UE may be configured to drop the UCI transmission if
the puncturing ratio exceeds a predefined threshold.
[0088] If, at step 200, the UE determines that multiple UL CCs have
been scheduled, the UE checks whether any of the UL CCs are
available UL CCs in step 204. The available UL CC(s) may be defined
to only include UL CC(s) that are allocated by dynamic grant and
that do not transmit SRB or MAC CE, for example.
[0089] If there is no available UL CC, the UE selects one of the UL
CCs among the scheduled UL CCs using a predefined selection rule in
step 206. For example, the UE may select the CC having the lowest
index. As an alternative, a priority for SPS, SRB and MAC CE can be
defined as described above (see, for example, Table 3) and the CC
having the lowest priority can be selected. In general, for
example, VoIP transmitted in SPS resource or other real-time
services and SRB have a higher priority than MAC CE to minimize
delay. After selecting the CC, the UCI is included in the UL CC in
step 202.
[0090] Finally, if there are available UL CCs, the UE selects one
CC from the set of available UL CCs in step 208 and, in step 202,
includes the UCI in the selected CC.
[0091] As another alternative for using implicit signaling as
described above, in order to avoid a relatively large puncturing
loss, if a UL CC is scheduled with a smaller number of physical
resource blocks (PRBs) than a certain PRB threshold, then that UL
CC could be precluded from transmitting UCI. In other words, UCI
may not be transmitted on a given UL CC if a PRB threshold is not
met. Instead, the next available UL CC may be used to transmit UCI
based on implicit selection. This threshold may be pre-defined in a
similar manner to that described above with respect to carrier
ranking, or may be configured by higher layer signaling. In an
embodiment, different thresholds may be configured per UL CC.
[0092] As another alternative to the implicit signaling methods
described above, one or more additional parameters may be
considered when the UE selects UCI CC with the implicit method. An
exemplary parameter that may be considered when using implicit
signaling may be transmission node. In this case, a certain UL CC
may be prioritized as a UCI CC based on transmission mode. For
example, if a UL CC is configured with a multiple antenna port
transmission mode, the UL CC may be prioritized to transmit UCI
because the puncturing loss would not be as significant compared
with UL CCs configured to use single antenna port transmission.
[0093] Another exemplary parameter that may be considered when
using implicit signaling may be the number of spatial layers in the
case of MIMO. In this case, a UL CC scheduled with a higher number
of spatial layers may be prioritized as a UCI CC. Because a lower
number of spatial layers might lead to a lower data rate, the UL CC
with the higher number of spatial layers scheduled is more
appropriate to transmit UCI CC, relative to the UL CC scheduled
with the lower number of spatial layers. In this manner, a
relatively large puncturing loss may be avoided.
[0094] Another exemplary parameter that may be considered when
using implicit signaling may be transport block size. In this case,
when the information bit size is relatively small compared to the
UCI bit size, the puncturing loss could be significant. Puncturing
loss may be reduced by selecting a UL CC scheduled with a higher
transport block size.
[0095] Another exemplary parameter that may be considered when
using implicit signaling may be the modulation and coding scheme
(MCS). In this case, when the information bit size and the UCI bit
size are fixed, the puncturing loss may be proportional to the MCS
level. Accordingly, the puncturing loss may be more severe when the
higher MCS level is scheduled. In order to avoid the relatively
large puncturing loss, the UCI CC may be selected as a UL CC
scheduled with the lower MCS level.
[0096] Another exemplary parameter that may be considered when
using implicit signaling may be the transmission number. When the
initial transmission is scheduled, the base station would be able
to consider the existence of UCI so that the resource can be
increased to compensate for the puncturing loss. However, for the
retransmission, it may not be difficult for the base station to
expect the future UCI transmission. In addition, a large
re-transmission may happen when the channel situation is worse than
the base station expects, and it would be important to transmit it
successfully as soon as possible. If UCI is transmitted on a UL CC
performing the retransmission, it may be likely to experience
another transmission due to puncturing. Therefore, it could be
beneficial to transmit UCI on a UL CC transmitting the initial
transmission or on a small number of retransmissions.
[0097] Any of the five parameters described above might be used
individually, combined with each other, or combined with the above
UCI CC information. Additionally, the same rule for selecting the
UCI CC may be applied at both the UE transmitter and the base
station receiver. Similarly, the same information may be available
at both locations so that the base station may know on which UL CC
to expect a particular UCI transmission.
[0098] In some cases, only one CC or set of CCs is configured for
UCI transmission. The base station may signal the carrier (denoted
by UCI CC) to be used for UCI transmission by RRC signaling or
L1/L2 signaling to the UE. The signaling may be explicit or
implicit. In a simple form of implicit signaling, the lowest index
CC is always selected for UCI transmission. If this carrier is same
as the carrier for PUCCH transmission, it may not be necessary to
provide separate signaling. When no PUSCH resources are allocated
on the UCI CC, in the present system, the UE may still be able to
transmit UCI.
[0099] For example, the UE may be configured to transmit UCI on the
PUCCH. Even though PUSCH may be allocated on the other carriers, if
PUSCH is not allocated on the UCI CC, the UE may transmit UCI using
PUCCH. In some networks, it may be beneficial if some of the
carriers are not allowed to transmit PUSCH and PUCCH simultaneously
due to inter-modulation problems or the large power difference
between PUCCH and PUSCH. For example, in a network implementation
with three UL CCs (CC1, CC2, and CC3), CC1 and CC2 may be UCI
carriers and CC1 is a PUCCH carrier. If CC1 is scheduled for PUSCH,
then UCI may be transmitted in CC1 (within the PUSCH resource
multiplexed with UL-SCH data, for example). However, if only CC3 is
scheduled for PUSCH, for instance, then PUSCH in CC3 and PUCCH in
CC1 (with PUCCH transmission carrying the UCI) may be
simultaneously transmitted.
[0100] Alternatively, the UE may transmit the UCI on another CC
with a scheduled PUSCH. In that case, the UE selects one PUSCH
scheduled CC among non-UCI CCs for transmission of UCI.
Alternatively, the UE may transmit over all non-UCI CCs. If the
puncturing ratio is below a predefined threshold, the UE may
transmit the UCI on the scheduled non-UCI CCs. Otherwise, the UE
may transmit the UCI using the PUCCH on the UCI CC.
[0101] Alternatively, the UE's available CCs may be separated into
two categories. The first category of CCs may be used, for example,
for special transmissions such as delay sensitive transmissions
like SPS, while the other category of CCs could be used for general
transmission purposes. This could be initially configured by the
base station and reconfigured from time to time.
[0102] The categories could be updated and signaled to the UE by
the base station. When there is at least one configured CC in the
general transmission category, the UE may avoid transmitting UCI on
the CCs that are intended for delay sensitive transmission (e.g.,
those CCs in the first category). If no CC is configured in the
general transmission category, the UE may transmit UCI on CCs that
are ordinarily used for special transmission when the CC is not
transmitting SPS or other delay sensitive transmission.
[0103] In this implementation, the base station may need to
configure at least one CC in the general transmission category. If
there is more than one CC configured in general transmission
category, the UE could transmit UCI on the general-transmission CCs
at the same time, or only transmit UCI on one of the CCs, depending
on some pre-defined rule, for example, by transmitting on the CC
with the lowest carrier index.
[0104] In another implementation, after UCI CC is selected, the UE
can transmit delay-sensitive data on CCs not transmitting UCI to
avoid the puncturing loss from UCI transmission. For example, when
CC1, CC4 and CC5 are scheduled, the UE selects CC4 as UCI CC. The
UE can then select one of CC1 and CC5 to transmit delay-sensitive
data. Among all the scheduled CCs not transmitting UCI, the CC(s)
selected to transmit delay-sensitive data can be based on a
predefined rule, using parameters such as carrier index, MCS or
bandwidth.
[0105] In yet another implementation, after the UCI CC is selected,
the granted resources of the scheduled UL CCs are ordered such that
the resources of the UL CC selected for UCI transmission are placed
last or placed such that it is not the first scheduled UL CC in the
order. The UE may then perform logical channel and MAC CE
prioritization on the ordered UL resources across the scheduled UL
CCs when deciding how to map the logical channel traffic and MAC CE
on to the scheduled UL CCs. For example, when CC1, CC4 and CC5 are
scheduled, the UE may select CC4 for UCI transmission. The UE can
order the granted resources of these three scheduled CCs such that
UL resources of CC4 are placed last. For example, the granted UL
resources may be ordered as follows: resources for CC1, followed by
resources for CC5, followed by resources for CC4, such that UE
performs logical channel and MAC CE prioritization following this
order when mapping the logical channel traffic and MAC CE to the
resources across the scheduled UL CCs.
[0106] As another alternative for carrier sets for UCI, in order to
avoid a relatively large puncturing loss, the UCI transmission
might not be transmitted on a UL CC if the number of scheduled PRBs
on the UL CC is smaller than a certain threshold. This threshold
may be pre-defined in a manner similar to that described above with
respect to carrier ranking, or may be configured by higher layer
signaling. In an embodiment, different thresholds may be configured
per UL CC.
[0107] Again, both the UE and base station may be aware of the
number of scheduled PRBs for a particular UL CC and the predefined
or configured threshold. In this case, the base station may know
whether or not to expect a UCI transmission on a particular UL
CC.
[0108] Alternatively, to accommodate an increase in the UCI
transmitted by a UE, the equation used to identify the appropriate
number of coded symbols for a subframe can be modified. In existing
networks, the number of coded symbols for HARQ-ACK (denoted by
Q'.sub.ACK), RI (denoted by Q'.sub.RI) and CQI/PMI (denoted by
Q'.sub.CQI/RI) can be calculated using equation (1) described above
(see, for example, TS 36.212 in Section 5.2.4.1 "3.sup.rd
Generation Partnership Project; Technical Specification Group Radio
Access Network; Evolved Universal Terrestrial Radio Access
(E-UTRA); Multiplexing and channel coding (Release 8)"). In the
present implementation, however, to accommodate the increase in UCI
data being transmitted for carrier aggregation, the equation is
adjusted to compensate.
[0109] In some networks, the maximum number of coded symbols for
HARQ-ACK or RI is limited up to 4M.sub.sc.sup.PUSCH to avoid
substantial puncturing and to fix the SC-FDMA symbols for RIs. RI
coded symbols are fixed to locate on the SC-FDMA symbols next to
the SC-FDMA symbols containing the HARQ-ACK coded symbols.
4M.sub.sc.sup.PUSCH is four times of the number of scheduled
frequency resources within one SC-FDMA symbol, which would
ordinarily be sufficient to support up to four HARQ-ACKs--the
maximum number of HARQ-ACKs in Release 8. However, as shown in
Table 1, if up to 12 HARQ-ACK bits are to be transmitted (as may be
the case in carrier aggregation), the required number of SC-FDMA
symbols may exceed four SC-FDMA symbols if the scheduled frequency
resource is small. As such, the upper limit of equation (1) may be
modified to provide a larger number of coded symbols. An example of
the modified equation is found in equation (3), below. As shown in
equation (3), the maximum number of coded symbols is increased from
4M.sub.sc.sup.PUSCH to 6M.sub.sc.sup.PUSCH. Note, however, that the
multiplier of `6` shown in equation (3) may be replaced with other
multipliers depending upon the system implementation.
Equation ( 3 ) ##EQU00004## Q ACK ' = min ( O M sc PUSCH - initial
N symb PUSCH - initial .beta. offset PUSCH r = 0 C - 1 K r , 6 M sc
PUSCH ) ##EQU00004.2##
[0110] After increasing the number of coded symbols in accordance
with equation (3), it is necessary to position each of the
additional symbols within an RB subframe. FIG. 7 is an illustration
of an example subframe showing candidate locations for an increased
number of HARQ-ACK symbols. Referring to FIG. 7, the new coded
symbols (those symbols exceeding 4 HARQ ACK/NACKs) can be the
located next to the SC-FDMA symbol after the coded symbols for RI
(see REs encircled by elements 300 of FIG. 7). Alternatively,
HARQ-ACKs may first be transmitted continuously over the SC-FDMA
symbols, with transmission of the RIs following. Generally,
HARQ-ACK is more important than RIs, and should be located close to
the RS.
[0111] Alternatively, if multiple UL CCs are scheduled, the
remaining coded symbols can be transmitted in the next UL CCs.
However, the other UL CCs may be scheduled with a different MCS and
frequency resource. Because the number of coded symbols for UCI in
PUSCH is determined by the PUSCH MCS, it may be difficult to merely
insert the remaining coded symbols into another UL CC. If the
number of coded symbols for ACK/NACK or RI is larger than
4M.sub.sc.sup.PUSCH, the ACK/NACK or RI information may be
distributed to multiple UL CCs.
[0112] FIG. 7A is an illustration of an example subframe showing
UCI transmission in clustered DFT-S-OFDM, in which two clusters
(700A and 700B) are allocated for PUSCH 702 transmission and
ACK/NACK (704A, 704B, 704C, and 704D), or RI (706A, 706B, 706C, and
706D) may be distributed over the two clusters. In Rel-10, multiple
kinds of PUSCH transmission schemes may be supported, such as
clustered DFT-S-OFDM and SU-MIMO, in addition to the single antenna
contiguous PUSCH transmission scheme used in Rel-8. The actual
PUSCH transmission scheme may be indicated to the UE with higher
layer signaling or by a corresponding DCI format. Depending on the
selected PUSCH transmission scheme, the actual location of UCI may
be different in order to take advantage of the particular
characteristics of each transmission scheme.
[0113] While FIG. 7A shows the use of two clusters, three or more
clusters might be used in different embodiments. Transmitting
ACK/NACK and RI over multiple clusters, such as in FIG. 7A, may
provide more frequency diversity relative to transmitting ACK/NACK
and RI in only one cluster. CQI can also be transmitted over
multiple clusters. Alternatively, because the reliability of CQI
might not be as important as ACK/NACK or RI, CQI may be transmitted
in one cluster for simplicity.
[0114] When a UL MIMO mode is configured, if the same UCI
information is repeated over multiple layers or code words,
diversity gain might be achieved. Alternatively, rank 1 (single
layer) precoded UL MIMO may also increase the directivity of the
transmission and can also provide both diversity and precoding
(array) gain without repeating UCI. While repeating UCI and
transmitting UCI on different layers may provide diversity gain and
may function well in conditions where precoding is not feasible,
repeating UCI may reduce or eliminate the precoding gain.
Therefore, the transmitted power used to reach error rate targets
can be different, and different power offsets for rank 1 and rank 2
transmissions may be desired or required.
[0115] When the additional diversity gain can be achieved in the
clustered DFT-S-OFDM or UL MIMO, the same reliability of UCI may be
obtained with a smaller number of coded symbols relative to a UCI
transmission in the contiguous PUSCH transmission scheme. A smaller
number of coded symbols for UCI may lead to a reduction of the
puncturing loss. In Rel-8, the number of UCI information bits, the
scheduled bandwidth, the number of SC-FDMA symbols per subframe,
the total transport block size and beta offset are used to derive
the number of coded symbols for UCI, as described above with
respect to UCI transmission. In addition, the actual PUSCH
transmission scheme may be considered to derive the number of coded
symbols for UCI.
[0116] In an embodiment, different beta offsets may be signaled for
each PUSCH transmission scheme. The following table 3A shows an
example of beta offset information for ACK/NACK with respect to
different PUSCH transmission schemes. This information may be
signaled with higher layer signaling. The UE may apply the beta
value based on the actual scheduled PUSCH transmission scheme.
TABLE-US-00004 TABLE 3A Beta value PUSCH transmission scheme
.beta..sub.offset.sup.HARQ-ACK,1 Contiguous PUSCH transmission
(Rel-8 PUSCH transmission) .beta..sub.offset.sup.HARQ-ACK,2
Clustered DFT-S-OFDM .beta..sub.offset.sup.HARQ-ACK,3 UL MIMO with
rank 1 .beta..sub.offset.sup.HARQ-ACK,4 UL MIMO with rank 2
[0117] Instead of signaling all different beta offset values, the
UE may calculate the beta offset value based on the number of
scheduled clusters, the number of code words, or the number of
layers that transmit UCI information when one beta offset value is
signaled. An example equation (Equation 4) is given by:
.beta..sub.offset.sup.HARQ-ACK=.beta..sub.offset,sig.sup.HARQ-ACK.times.-
(1+.DELTA..sub.c.times.(N.sub.clusters-1)+.DELTA..sub.1.times.(N.sub.layer-
s-1)) Equation (4)
[0118] In equation (4), above, .beta..sub.offset,sig.sup.HARQ-ACK
is the beta offset signaled by higher layer signaling,
.DELTA..sub.c is the offset for the clustered DFT-S-OFDM
transmission, N.sub.clusters is the number of clusters,
.DELTA..sub.l is the offset for UL MIMO, and N.sub.layers is the
number of layers. The values .DELTA..sub.c and .DELTA..sub.l may be
predefined with a fixed value, or may be configured by higher layer
signaling. In an embodiment, the signaled beta offset value may be
same as the one for Rel-8 PUSCH transmissions. In the case of Rel-8
PUSCH transmissions, .beta..sub.offset.sup.HARQ-ACK may be
.beta..sub.offset,sig.sup.HARQ-ACK because N.sub.clusters has a
value of 1 and N.sub.layers has a value of 1.
[0119] In another implementation, the UE is configured to drop
UL-SCH data when too many PUSCH resources are required for UCI
transmission. This may occur, for example, if a UE transmits UCI
for an increased number of DL CCs as discussed above. In order to
determine whether too many PUSCH resources are required or not, the
required number of coded symbols for UCI and the PUSCH resource can
be compared. As an example, the puncturing ratio can be calculated
using equation (5), below.
R puncturing = Q ACK ' + Q RI ' + Q CQI / PMI ' N symb PUSCH M sc
PUSCH Equation ( 5 ) ##EQU00005##
[0120] In this implementation, the UE is configured to compare
R.sub.puncturing with a predetermined puncturing level threshold.
The threshold can be signaled by RRC signaling or defined in the
specification, for example. If R.sub.puncturing is larger than the
threshold, the UE does not transmit some UL-SCH data and only
transmits UCI in the PUSCH. Otherwise, UCI and UL-SCH data may be
multiplexed and transmitted using the PUSCH resource.
[0121] Because HARQ for PUSCH transmission is synchronous, the
redundancy version (RV) sequence is fixed unless there is a grant
from the base station. As such, after the data is punctured due to
UCI transmission, the punctured data will have a chance to be
re-transmitted after three retransmissions unless the base station
changes RV to be transmitted with the grant. If RV0 having a large
amount of systematic bits happens to be severely punctured due to
UCI, it is likely that this data would be successfully decoded four
retransmissions later after RV0 is retransmitted again. In that
sense, if the puncturing is severe, it might be helpful to suspend
the PUSCH data and resume in the next HARQ timing.
[0122] Alternatively, if R.sub.puncturing is smaller than the
threshold, UCI is transmitted with one scheduled UL CC. Otherwise,
UCI is divided and transmitted on multiple UL CCs.
[0123] In another embodiment, UL-SCH dropping may be decided based
on the number of resource blocks scheduled by the base station.
Although the normal UCI transmission may not be requested by the
DCI format, the UE may decide whether UL-SCH data is dropped based
on the number of scheduled PRBs at a subframe in which UCI is
expected to be transmitted with UL-SCH data. If the number of
scheduled PRBs in the UL CC that is supposed to transmit UCI is
smaller than a certain threshold, the UL-SCH data in this carrier
may be dropped. This threshold may be pre-defined similarly as
described above with respect to carrier ranking, or may be
configured by higher layer signaling. A different threshold may be
configured per UL CC. Alternatively, instead of the number of
resource blocks, the transport block size may be used to decide
whether to drop the UL-SCH data in the carrier.
[0124] In another embodiment, the dropping of UL-SCH data may be
enabled or disabled per CC. For example, for UL CC scheduled SPS,
the dropping of UL-SCH data may be disabled. In this case, the
dropping of UL-SCH data may be configured by RRC signaling or MAC
CE. When dropping of UL-SCH is disabled, but the dropping criterion
or criteria are met, UCI may be transmitted in other scheduled UL
CCs. If there is no available UL CC, or if UL-SCH data dropping is
disabled for all available UL CCs, then UCI might be dropped at
this subframe. Once the CC is enabled to support the dropping of
UL-SCH data, the dropping of UL-SCH data may then occur, or may be
determined based on the threshold as described above.
[0125] In another embodiment, when the criterion or criteria for
dropping UL-SCH data are met, the UE may drop UCI or UL-SCH data
based on a priority. Again, examples of criteria for dropping
UL-SCH data include a large amount of UCI being transmitted, the
puncturing ratio being larger than a threshold, or the number of
scheduled PRBs being larger than a threshold. The priority may be
based on the type of data, considering the characteristics of the
data. For example, CQI/PMI/RI may be dropped first. If the
criterion or criteria for dropping UL-SCH data are still met, then
UL-SCH data may be dropped and/or HARQ-ACK/NACK may be the last to
be dropped. Additionally, which UCI is dropped first may be
signaled by higher layer signaling, or may be predefined.
[0126] In another embodiment, when the dropping criterion or
criteria are met, the UE can reduce the amount of UCI.
Additionally, CQI/PMI/RI of some DL CC may be dropped, or only
limited information may be transmitted. In another embodiment,
HARQ-ACK/NACK bundling may be used. When using HARQ-ACK/NACK
bundling, a smaller number of HARQ-ACK/NACK bits than the required
or desired number of HARQ ACK-NACK bits may be generated based on
the HARQ results of multiple transport blocks.
[0127] Alternatively, explicit signaling may be used to indicate
whether UL-SCH data is included with UCI transmission. This
explicit signaling may also be included in DCI format(s) for
dynamic uplink grants in addition to CQI request which is already
supported in Release 8. The explicit signaling may also be included
in SPS grants. Table 4 provides an illustration of an exemplary
information bit for UL-SCH data with UCI transmission indicating
whether the transmission includes UL-SCH data.
TABLE-US-00005 TABLE 4 BIT value UL-SCH data 0 Transmission 1 No
transmission
[0128] To avoid introducing additional signaling bits, it could be
possible to reuse the CQI request bit if some of UL CCs are not
used for aperiodic CQI transmissions. Alternatively, the base
station may dynamically indicate whether UCI can be included in the
scheduled PUSCH. If the base station signals not to include UCI in
the corresponding UL CC, UCI could be dropped, transmitted in
PUCCH, or transmitted in other scheduled UL CC. This signaling may
be included in an SPS grant as well as a dynamic uplink grant.
[0129] The present system can be used to minimize the affect of UCI
transmission on high QoS data when UCI and UL-SCH data are
simultaneously transmitted in the same subframe. The system allows
the UE to select UL CC(s) transmitting lower-QoS data for UCI
transmission using explicit or implicit signaling of the ranking of
UCI CC(s) or UCI carrier set. Consequently, the determination of
UCI CC would minimize the chance of puncturing resources used for
high QoS data transmissions, which will maintain the performance of
at least high QoS data even if UCI is transmitted in the PUSCH
resource. Additionally, the present system allows devices to not
transmit UCI or UL-SCH data when the puncturing loss is severe or
high QoS data is transmitted in the PUSCH.
[0130] FIG. 8 illustrates a wireless communications system
including an embodiment of a UE 10. The UE 10 is operable for
implementing aspects of the disclosure, but the disclosure should
not be limited to these implementations. Though illustrated as a
mobile phone, the UE 10 may take various forms including a wireless
handset, a pager, a personal digital assistant (PDA), a portable
computer, a tablet computer, a laptop computer. Many suitable
devices combine some or all of these functions. In some embodiments
of the disclosure, the UE 10 is not a general purpose computing
device like a portable, laptop or tablet computer, but rather is a
special-purpose communications device such as a mobile phone, a
wireless handset, a pager, a PDA, or a telecommunications device
installed in a vehicle. The UE 10 may also be a device, include a
device, or be included in a device that has similar capabilities
but that is not transportable, such as a desktop computer, a
set-top box, or a network node. The UE 10 may support specialized
activities such as gaming, inventory control, job control, and/or
task management functions, and so on.
[0131] The UE 10 includes a display 712. The UE 10 also includes a
touch-sensitive surface, a keyboard or other input keys generally
referred as 714 for input by a user. The keyboard may be a full or
reduced alphanumeric keyboard such as QWERTY, Dvorak, AZERTY, and
sequential types, or a traditional numeric keypad with alphabet
letters associated with a telephone keypad. The input keys may
include a track wheel, an exit or escape key, a trackball, and
other navigational or functional keys, which may be inwardly
depressed to provide further input function. The UE 10 may present
options for the user to select, controls for the user to actuate,
and/or cursors or other indicators for the user to direct.
[0132] The UE 10 may further accept data entry from the user,
including numbers to dial or various parameter values for
configuring the operation of the UE 10. The UE 10 may further
execute one or more software or firmware applications in response
to user commands. These applications may configure the UE 10 to
perform various customized functions in response to user
interaction. Additionally, the UE 10 may be programmed and/or
configured over-the-air, for example from a wireless base station,
a wireless access point, or a peer UE 10.
[0133] Among the various applications executable by the UE 10 are a
web browser, which enables the display 712 to show a web page. The
web page may be obtained via wireless communications with a
wireless network access node, a cell tower, a peer UE 10, or any
other wireless communication network or system 710. The network 710
is coupled to a wired network 718, such as the Internet. Via the
wireless link and the wired network, the UE 10 has access to
information on various servers, such as a server 720. The server
720 may provide content that may be shown on the display 712.
Alternately, the UE 10 may access the network 710 through a peer UE
10 acting as an intermediary, in a relay type or hop type of
connection.
[0134] FIG. 9 shows a block diagram of the UE 10. While a variety
of known components of UEs 10 are depicted, in an embodiment a
subset of the listed components and/or additional components not
listed may be included in the UE 10. The UE 10 includes a digital
signal processor (DSP) 802 and a memory 804. As shown, the UE 10
may further include an antenna and front end unit 806, a radio
frequency (RF) transceiver 808, an analog baseband processing unit
810, a microphone 812, an earpiece speaker 814, a headset port 816,
an input/output interface 818, a removable memory card 820, a
universal serial bus (USB) port 822, a short range wireless
communication sub-system 824, an alert 826, a keypad 828, a liquid
crystal display (LCD), which may include a touch sensitive surface
830, an LCD controller 832, a charge-coupled device (CCD) camera
834, a camera controller 836, and a global positioning system (GPS)
sensor 838. In an embodiment, the UE 10 may include another kind of
display that does not provide a touch sensitive screen. In an
embodiment, the DSP 802 may communicate directly with the memory
804 without passing through the input/output interface 818.
[0135] The DSP 802 or some other form of controller or central
processing unit operates to control the various components of the
UE 10 in accordance with embedded software or firmware stored in
memory 804 or stored in memory contained within the DSP 802 itself.
In addition to the embedded software or firmware, the DSP 802 may
execute other applications stored in the memory 804 or made
available via information carrier media such as portable data
storage media like the removable memory card 820 or via wired or
wireless network communications. The application software may
comprise a compiled set of machine-readable instructions that
configure the DSP 802 to provide the desired functionality, or the
application software may be high-level software instructions to be
processed by an interpreter or compiler to indirectly configure the
DSP 802.
[0136] The antenna and front end unit 806 may be provided to
convert between wireless signals and electrical signals, enabling
the UE 10 to send and receive information from a cellular network
or some other available wireless communications network or from a
peer UE 10. In an embodiment, the antenna and front end unit 806
may include multiple antennas to support beam forming and/or
multiple input multiple output (MIMO) operations. As is known to
those skilled in the art, MIMO operations may provide spatial
diversity which can be used to overcome difficult channel
conditions and/or increase channel throughput. The antenna and
front end unit 806 may include antenna tuning and/or impedance
matching components, RF power amplifiers, and/or low noise
amplifiers.
[0137] The RF transceiver 808 provides frequency shifting,
converting received RF signals to baseband and converting baseband
transmit signals to RF. In some descriptions a radio transceiver or
RF transceiver may be understood to include other signal processing
functionality such as modulation/demodulation, coding/decoding,
interleaving/deinterleaving, spreading/despreading, inverse fast
Fourier transforming (IFFT)/fast Fourier transforming (FFT), cyclic
prefix appending/removal, and other signal processing functions.
For the purposes of clarity, the description here separates the
description of this signal processing from the RF and/or radio
stage and conceptually allocates that signal processing to the
analog baseband processing unit 810 and/or the DSP 802 or other
central processing unit. In some embodiments, the RF Transceiver
808, portions of the Antenna and Front End 806, and the analog base
band processing unit 810 may be combined in one or more processing
units and/or application specific integrated circuits (ASICs).
[0138] The analog baseband processing unit 810 may provide various
analog processing of inputs and outputs, for example analog
processing of inputs from the microphone 812 and the headset 816
and outputs to the earpiece 814 and the headset 816. To that end,
the analog baseband processing unit 810 may have ports for
connecting to the built-in microphone 812 and the earpiece speaker
814 that enable the UE 10 to be used as a cell phone. The analog
baseband processing unit 810 may further include a port for
connecting to a headset or other hands-free microphone and speaker
configuration. The analog baseband processing unit 810 may provide
digital-to-analog conversion in one signal direction and
analog-to-digital conversion in the opposing signal direction. In
some embodiments, at least some of the functionality of the analog
baseband processing unit 810 may be provided by digital processing
components, for example by the DSP 802 or by other central
processing units.
[0139] The DSP 802 may perform modulation/demodulation,
coding/decoding, interleaving/deinterleaving,
spreading/despreading, inverse fast Fourier transforming
(IFFT)/fast Fourier transforming (FFT), cyclic prefix
appending/removal, and other signal processing functions associated
with wireless communications. In an embodiment, for example in a
code division multiple access (CDMA) technology application, for a
transmitter function the DSP 802 may perform modulation, coding,
interleaving, and spreading, and for a receiver function the DSP
802 may perform despreading, deinterleaving, decoding, and
demodulation. In another embodiment, for example in an orthogonal
frequency division multiplex access (OFDMA) technology application,
for the transmitter function the DSP 802 may perform modulation,
coding, interleaving, inverse fast Fourier transforming, and cyclic
prefix appending, and for a receiver function the DSP 802 may
perform cyclic prefix removal, fast Fourier transforming,
deinterleaving, decoding, and demodulation. In other wireless
technology applications, yet other signal processing functions and
combinations of signal processing functions may be performed by the
DSP 802.
[0140] The DSP 802 may communicate with a wireless network via the
analog baseband processing unit 810. In some embodiments, the
communication may provide Internet connectivity, enabling a user to
gain access to content on the Internet and to send and receive
e-mail or text messages. The input/output interface 818
interconnects the DSP 802 and various memories and interfaces. The
memory 804 and the removable memory card 820 may provide software
and data to configure the operation of the DSP 802. Among the
interfaces may be the USB interface 822 and the short range
wireless communication sub-system 824. The USB interface 822 may be
used to charge the UE 10 and may also enable the UE 10 to function
as a peripheral device to exchange information with a personal
computer or other computer system. The short range wireless
communication sub-system 824 may include an infrared port, a
Bluetooth interface, an IEEE 802.11 compliant wireless interface,
or any other short range wireless communication sub-system, which
may enable the UE 10 to communicate wirelessly with other nearby
mobile devices and/or wireless base stations.
[0141] The input/output interface 818 may further connect the DSP
802 to the alert 826 that, when triggered, causes the UE 10 to
provide a notice to the user, for example, by ringing, playing a
melody, or vibrating. The alert 826 may serve as a mechanism for
alerting the user to any of various events such as an incoming
call, a new text message, and an appointment reminder by silently
vibrating, or by playing a specific pre-assigned melody for a
particular caller.
[0142] The keypad 828 couples to the DSP 802 via the interface 818
to provide one mechanism for the user to make selections, enter
information, and otherwise provide input to the UE 10. The keyboard
828 may be a full or reduced alphanumeric keyboard such as QWERTY,
Dvorak, AZERTY and sequential types, or a traditional numeric
keypad with alphabet letters associated with a telephone keypad.
The input keys may include a track wheel, an exit or escape key, a
trackball, and other navigational or functional keys, which may be
inwardly depressed to provide further input function. Another input
mechanism may be the LCD 830, which may include touch screen
capability and also display text and/or graphics to the user. The
LCD controller 832 couples the DSP 802 to the LCD 830.
[0143] The CCD camera 834, if equipped, enables the UE 10 to take
digital pictures. The DSP 802 communicates with the CCD camera 834
via the camera controller 836. In another embodiment, a camera
operating according to a technology other than Charge Coupled
Device cameras may be employed. The GPS sensor 838 is coupled to
the DSP 802 to decode global positioning system signals, thereby
enabling the UE 10 to determine its position. Various other
peripherals may also be included to provide additional functions,
e.g., radio and television reception.
[0144] FIG. 10 illustrates a software environment 902 that may be
implemented by the DSP 802. The DSP 802 executes operating system
drivers 904 that provide a platform from which the rest of the
software operates. The operating system drivers 904 provide drivers
for the UE hardware with standardized interfaces that are
accessible to application software. The operating system drivers
904 include application management services (AMS) 906 that transfer
control between applications running on the UE 10. Also shown in
FIG. 10 are a web browser application 908, a media player
application 910, and Java applets 912. The web browser application
908 configures the UE 10 to operate as a web browser, allowing a
user to enter information into forms and select links to retrieve
and view web pages. The media player application 910 configures the
UE 10 to retrieve and play audio or audiovisual media. The Java
applets 912 configure the UE 10 to provide games, utilities, and
other functionality. A component 914 might provide functionality
described herein.
[0145] The UE 10, base station, and other components described
above might include a processing component that is capable of
executing instructions related to the actions described above. FIG.
11 illustrates an example of a system 1000 that includes a
processing component 1010 suitable for implementing one or more
embodiments disclosed herein. In addition to the processor 1010
(which may be referred to as a central processor unit (CPU or DSP),
the system 1000 might include network connectivity devices 1020,
random access memory (RAM) 1030, read only memory (ROM) 1040,
secondary storage 1050, and input/output (I/O) devices 1060. In
some cases, some of these components may not be present or may be
combined in various combinations with one another or with other
components not shown. These components might be located in a single
physical entity or in more than one physical entity. Any actions
described herein as being taken by the processor 1010 might be
taken by the processor 1010 alone or by the processor 1010 in
conjunction with one or more components shown or not shown in the
drawing.
[0146] The processor 1010 executes instructions, codes, computer
programs, or scripts that it might access from the network
connectivity devices 1020, RAM 1030, ROM 1040, or secondary storage
1050 (which might include various disk-based systems such as hard
disk, floppy disk, or optical disk). While only one processor 1010
is shown, multiple processors may be present. Thus, while
instructions may be discussed as being executed by a processor, the
instructions may be executed simultaneously, serially, or otherwise
by one or multiple processors. The processor 1010 may be
implemented as one or more CPU chips.
[0147] The network connectivity devices 1020 may take the form of
modems, modem banks, Ethernet devices, universal serial bus (USB)
interface devices, serial interfaces, token ring devices, fiber
distributed data interface (FDDI) devices, wireless local area
network (WLAN) devices, radio transceiver devices such as code
division multiple access (CDMA) devices, global system for mobile
communications (GSM) radio transceiver devices, worldwide
interoperability for microwave access (WiMAX) devices, and/or other
well-known devices for connecting to networks. These network
connectivity devices 1020 may enable the processor 1010 to
communicate with the Internet or one or more telecommunications
networks or other networks from which the processor 1010 might
receive information or to which the processor 1010 might output
information.
[0148] The network connectivity devices 1020 might also include one
or more transceiver components 1025 capable of transmitting and/or
receiving data wirelessly in the form of electromagnetic waves,
such as radio frequency signals or microwave frequency signals.
Alternatively, the data may propagate in or on the surface of
electrical conductors, in coaxial cables, in waveguides, in optical
media such as optical fiber, or in other media. The transceiver
component 1025 might include separate receiving and transmitting
units or a single transceiver. Information transmitted or received
by the transceiver 1025 may include data that has been processed by
the processor 1010 or instructions that are to be executed by
processor 1010. Such information may be received from and outputted
to a network in the form, for example, of a computer data baseband
signal or signal embodied in a carrier wave. The data may be
ordered according to different sequences as may be desirable for
either processing or generating the data or transmitting or
receiving the data. The baseband signal, the signal embedded in the
carrier wave, or other types of signals currently used or hereafter
developed may be referred to as the transmission medium and may be
generated according to several methods well known to one skilled in
the art.
[0149] The RAM 1030 might be used to store volatile data and
perhaps to store instructions that are executed by the processor
1010. The ROM 1040 is a non-volatile memory device that typically
has a smaller memory capacity than the memory capacity of the
secondary storage 1050. ROM 1040 might be used to store
instructions and perhaps data that are read during execution of the
instructions. Access to both RAM 1030 and ROM 1040 is typically
faster than to secondary storage 1050. The secondary storage 1050
is typically comprised of one or more disk drives or tape drives
and might be used for non-volatile storage of data or as an
over-flow data storage device if RAM 1030 is not large enough to
hold all working data. Secondary storage 1050 may be used to store
programs that are loaded into RAM 1030 when such programs are
selected for execution.
[0150] The I/O devices 1060 may include liquid crystal displays
(LCDs), touch screen displays, keyboards, keypads, switches, dials,
mice, track balls, voice recognizers, card readers, paper tape
readers, printers, video monitors, or other well-known input/output
devices. Also, the transceiver 1025 might be considered to be a
component of the I/O devices 1060 instead of or in addition to
being a component of the network connectivity devices 1020. Some or
all of the I/O devices 1060 may be substantially similar to various
components depicted in the previously described drawing of the UE
10, such as the display 712 and the input 714.
[0151] While several embodiments have been provided in the present
disclosure, it should be understood that the disclosed systems and
methods may be embodied in many other specific forms without
departing from the spirit or scope of the present disclosure. The
present examples are to be considered as illustrative and not
restrictive, and the intention is not to be limited to the details
given herein. For example, the various elements or components may
be combined or integrated in another system or certain features may
be omitted, or not implemented.
[0152] Also, techniques, systems, subsystems and methods described
and illustrated in the various embodiments as discrete or separate
may be combined or integrated with other systems, modules,
techniques, or methods without departing from the scope of the
present disclosure. Other items shown or discussed as coupled or
directly coupled or communicating with each other may be indirectly
coupled or communicating through some interface, device, or
intermediate component, whether electrically, mechanically, or
otherwise. Other examples of changes, substitutions, and
alterations are ascertainable by one skilled in the art and may be
made without departing from the spirit and scope disclosed
herein.
[0153] To apprise the public of the scope of this invention, the
following claims are made.
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