(22) INTERNATIONAL APPLICATION PUBLSUED UNDER THE PATENT COOPERATION TREATY (PCT}
`(19) World Intellectual Property
`a
`EEE
`Organization
`
`international Boreat Wt
`
`(43) Yaternational Publication Date
`26 May 2087 (26.05.2017)
`
`WIiPOLPCT
`
`(18) International Publication Number
`WO 2017/087357 Al
`
`GY)
`
`Internations] Patent Classification:
`ATOSL SAN 2006.01)
`SUSE LAA (2006.08)
`
`Q@y
`
`International Application Nawhber:
`
`PCTAU S20 EGAIOI GTS
`
`(8)
`
`(74)
`
`Agents: BENDSEIL, dames JF. ct al, Arent Pox, LLP,
`Vi? K Street, NAW. Washington, District af Columbia
`
`T0006-5344 GUS).
`
`(22)
`
`Iuternational Ying Bate:
`
`iS November 2016 (1S. E2016}
`
`English
`
`English
`
`(8)
`
`Filing Language:
`
`Publication Language:
`
`(26)
`
`(305
`
`Priority Data:
`&2255,890
`16 November W145 (16.11, 2015)
`[8350988
`14 November 2016 (14.11.2018)
`
`Applicant: QUALCOMM INCORPORATED[1
`ATYS:
`taternational
`iP Administration, 5775 Morethomse
`
`
`
`Drive, San Diego, California 92h EU f4 COS}.
`
`US
`Us
`
`
`
`‘1OMAMf“incorpor.
`California 9212 f-
`
`Ind (US).
`
`Designated States Castes: otheneise indicated, for every
`kind of metional protection available}: AL, AC, AL, AM,
`AQ, AT, AQ, AZ, BA, BB, BG, BH, BN, BR, BW, BY,
`
`BZ, CA, CH,
`OL, CN, OO, CR CU, C24, OE DY DIK, DM,
`
`1G, D4, EC, EE, EG, ES, FL GB, GD, GE, GHGM, GT,
`HN, AR, HU, YDIL, 8, 18, FS, JP, RE, RG, RN, RP, KR,
`KW, K4, LA, LO, LR, LR, LS, LU, LY, MA, MD, ME,
`MG, MEK, MIN, MW MX, MY) MZ, NANG, NIL SO NZ,
`OM), PAL PE, PG, PH, PL. PT, QA, RO, RS, RU RW, SA,
`SC, SD, SE, SO, SK, SE, SM, SY, SV, SY, PH, TY, PM,
`TN, TR. TT, Fé. UA, UG, US, U4. ¥C, VN, ZA, 2M,
`ZY,
`
`(84)
`
`Des:
`onaled States Gavess othervise indicated. for every
`
`regional protection avallubien ARIPO cBW, OH,
`ELE, LS, MW, MZ, NA, RW), SD. SL, ST, SZ,
`
`12, ‘UG. 2M, ZW), Murasian CAM, AZ, BY, Ror, KZ, RY,
`TH, FM), European (AL, AT, BE, BG, CH, CY, (CZ, DE,
`Da, BEL ES, FE, PR, cB. GR, HR, HU TE, IS PP, LT. RUS
`
`
`tinged on nex! pare}
`iG
`
`(34) ‘Pitle: TRCHNIQUES POR DOWNLINE ASSIGNMENTINDEX (DAD MANAGEMENT IN CARRIER AGGREGATION
`
`~ 800
`
`(57) Abstract: The present disclospre describes various as-
`pects nelated to techukqnes for downlak assignment sudex
`
`
`
`CDAD panagement In carer ageregation. In ote aspect,
`
`
`method is provided in which a user equipmetit
`re
`SAT indicatinga total mantber of CXLassignmentsorcode-
`words. Tis method may fimiher inchule interpreting the
`
`
`ALreceived fram the base station based at least on wheth-
`er ihe DAD is naaived from the base station ina DIL grace
`or 6 uplink (CL} grant.
`[ns ancther aspect, a method ts
`provided in which a base
`station determines whether ta
`
`
`transmit a DAT in a D
`8 uphink (UL) grant, acl
`
`transmits the PAY in the
`orang? or the L/L. grant to cen or
`mote bser equipmenis (URs} based on the deternination.
`
`
`
`wo2017/087357Al(MAE
`
`RECEIVE, AT A USER EQUIPMENT AND FROM A
`BASE STATION, A DOWNLINK ASSIGNMENT
`INDEX INDICATING A TOTAL NUMBER OF
`DOWNLINE ASSIGNMENTS OR CODEWORDS
`
`
`
`£20
`
`}
`
`INTERPRET, AT THE USER EQUIPMENT, THE
`
`DOWNLINK ASSIGNMENT INDEX RECENVED
`
`FROM THE BASE STATION BASED AT LEAST
`ON WHETHER THE DAI 1S RECEIVED FROM TRE
`BASE STATIONIN A DOWNLINK GRANT OR A
`UPLINK GRANT
`
`
`
`
`FIG. &
`
`

`

`WO2017/087357 ALENT
`
`LY, MC, ME, MT, NL, NO, PL, PT, RO, BS, SE, SH SK, Published:
`8M, TR}, OAPI (BE, BJ, CF. CG, CI, CM, GA, GN, GQ.
`GW, KM, ML, MR. NE. SN, TD, TE
`
`wht Gerrational search report (art PER)
`
`

`

`WO 2017/087387
`
`PCT/ES2016/061978
`
`1
`
`TECHNIQUES FOR DOWNLINK ASSIGNMENTENDEX (DAD
`MANAGEMENTIN CARRIER AGGREGATION
`
`CLAIM OF PRIORITY
`
`(o001
`
`The present application for patent claims priority to U.S. Non-Provisional Patent
`
`Application No, 15/350,988,
`
`filed November 14, 2016, entitled “Techniques for
`
`Downlink Assignment Index (DAI} Management in Carrier Aggregation,” and U.S.
`
`Provisional Patent Application No. 62/255,896,
`
`filed November 16, 2015, entitled
`
`“Techniques
`
`for Downlink Assignment
`
`Index (DAT) Management
`
`in Carrier
`
`Aggregation,” which is assigned to the assignee hereof, and hereby expressly
`
`incorporated by reference herein.
`
`BACKGROUND
`
`{0002}
`
`Aspects of this disclosure relate generally to telecommunications, and more particularly
`
`to techniques for downlink assignment index (DAI) management in carrier aggregation.
`
`10003]
`
`Wireless
`
`conwnunications networks
`
`are widely deployed to provide
`
`various
`
`conununication services such as voice, video, packet data, messaging, broadcast, and
`
`the like. These wireless networks may be multiple-access networks capable of
`
`supporting multiple users by sharing the available network resources. Examples of such
`
`miultiple-access networks include Code Division Multiple Access (CDMA) networks,
`
`Time Division Multiple Access (TDMA) networks, Frequeney Division Multiple
`
`Access (FDMA) networks, Orthogonal FDMA (OFDMA)networks, and Single-Carrier
`
`FDMA (SC-FDMA)}networks,
`
`[O80]
`
`A wireless communication network may include a mumber of base stations (e.z.,
`
`eNodeBs or eNBs} that can support communication for a number of user equipments
`
`(VEs}. A UE may communicate with a base station via the downlink and uplink. The
`
`downlink (or forward link) refers to the communicationlink from the base station to the
`
`LE, and the uplink {or reverse link} refers to the communication link from the UEte the
`
`base station.
`
`[0005]
`
`In some wireless comupunication networks, such as in Long Term Evolution (LTE), for
`
`example, a downlink assignment index (DAI} may be communicated by an eNB to an
`
`OE to prevent acknowledgment/negative-acknowledgment (ACK/NACK) errors that
`
`may oceur as part of Hybrid Automatic Repeat Request (HARQ) operations in which
`
`the UE bundles ACK/NACK feedback to the eNB. The use of the DAT in systems in
`
`

`

`WO 2017/087387
`
`PCT/ES2016/061978
`
`which multiple component carriers (CCs) are supported for carner aggregation may
`
`present some challenges, particularly as the namber of component carriers that are
`
`supported increases. Accordingly, it is desirable to have mechanisms that enable the use
`
`ofa DAI in a wide range ofcarrier aggregation scenarios.
`
`SUMMARY
`
`10006]
`
`The following presents a simplified summary of one or more aspects in order to provide
`
`a basic understanding af such aspects. This summary is not an extensive overview ofall
`
`contemplated aspects, and is intended to neither identify key or critical clernents ofall
`
`aspects nor delineate the scope of any or all aspects. Its sole purpose is to present some
`
`concepts of one or more aspects m a simplified form as a prelude to the more detailed
`
`description that 1s presented later.
`
`[0007}
`
`According to one example, a method fer downlmk C3.) assignment
`
`index (DAD
`
`management
`
`im an enhanced carrier aggregation (eCA) is provided. The example
`
`method may include receiving, at a user equipment (DE) and from a base station, a DAI
`
`indicating a total number of DL assignments or codewords; and interpreting, at the UE,
`
`the DAT received from the base station based at least on whether the DAI is received
`
`from the base station in a DI. grant or a uplink (UL) grant.
`
`{0008}
`
`lx another example, an apparatus
`
`for downlink (DL) assignment
`
`index (DAD
`
`management
`
`in am enhanced carrier aggregation (eCA) is provided. The example
`
`apparatus may inchide means for receiving, ai a user equipment (UE) and from a base
`
`station, a DAI indicating a total number of DL assignments or codewords: and means
`
`for interpreting, at the UE, the DAI received from the base station based at least on
`
`whether the DAI is received from the base station in a DLL grant or a uplink (UL) grant.
`
`[00094
`
`fn a further example, an apparatus for downlink (DL) assignment
`
`index (DA}
`
`management in an enhanced carrier aggregation (eCA) is provided that may include a
`
`memory configured to store data; and one or more processors commumicatively coupled
`
`with the memory, wherein the one or more processors and the memory are configured to
`
`reeeive, at a user equipment {UE} and from a base station, a DAI indicating a total
`
`number of DL assignments or codewords; and interpret, at the UE, the DAT received
`
`fromthe base station based at least on whether the DAI is received from the base station
`
`ina DL grant or auplink (UL) grant.
`
`19010}
`
`Additionally,
`
`im another example, a computer readable medium storing computer
`
`executable code for downlink (DL) assignment
`
`index (DAI) management
`
`in an
`
`

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`WO 2017/087387
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`PCT/ES2016/061978
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`Cea
`
`enhanced carrier aggregation (eC,A} is provided. The computer readable medium
`
`includes code for receiving, al a user equipment (UE) and from a base station, a DAI
`
`indicating a total number of DL assignments or codewords: and code for interpreting, at
`
`the UE, the DAT received from the base station based at least on whether the DAI is
`
`received from the base station ina DLgrant or a uplink (UL) grant.
`
`(O01 1}
`
`According to another example, a method for downlink (DL) assignment index (DAD
`
`management
`
`in an enhanced carrier aggregation (eCA) is provided. The example
`
`method includes deterrnining, at a base station, whether to ransmit a DAI ina DL grant
`
`or a uplink (UL) grant, wherein the DAI indicates a total mumber of DLassignments or
`
`codewords; and transmitting, from the base station, the DAL in the DL grant or the UL
`
`grant to one or mere user equipments (LYEs} based on the determination,
`
`10012]
`
`In another example, an apparatus
`
`for downlink (DL) assignment
`
`index (DAD
`
`management
`
`in an enhanced carrier aggregation (eCA} is provided. The example
`
`apparatus mayinclude means for determining. at a base station, whether to transmit a
`
`DAT in a DL grant or a uplink (UL) grant, wherein the DAI mdicates a total number of
`
`DL assignments or codewords; and means for transmifting, from the base station, the
`
`DAL in the DL grant or the UL grant te one or more user equipments (UIEs) based on the
`
`determination.
`
`[0013}
`
`in a further example, an apparatus for
`
`downlink (DL) assignment
`
`index (DAT)
`
`management in an enhanced carrier aggregation (eCA) is provided that may include 2
`
`memoryconfigured to store data; and one or more processors communicatively coupled
`
`with the memory, wherein the one or more processors and the memory are configured to
`
`determine, at a base station, whether to transmit a DAI ina DLgrant or a uplink COL)
`
`grant, wherein the DAI indicates a total number of DLassignments or codewords; and
`
`transnut, from the base station, the DAT in the DL grant or the ULgrant to one or more
`
`user equipments (UEs) based an the determination.
`
`fO014]
`
`Addinonally,
`
`in another example, a computer readable mediam storimg computer
`
`executable code for downlink (DL} assignment
`
`index (DAT) management
`
`in an
`
`enhanced carrier aggregation (e(C.A) is provided that may include code for determining.
`
`at a base station, whether to transmit a DA] m a DL grant or a uplink (UL) grant,
`
`wherein the DAI indicates a total number of DL assignments or codewords; and code
`
`for transmitting, from the base station, the DA] in the DL grant or the UL grant to one
`
`or more user equipments (LIEs) based on the deterrmimation.
`
`

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`WO 2017/087387
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`PCT/ES2016/061978
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`4
`
`fQD15] Various aspects and features of the disclosure are described in further detail below with
`
`reference lo various examples thereof as. shown in the accompanying drawings. While
`
`the present disclosure is described below with reference to various examples, it should
`
`be understood that the present disclosure is not limited thereto. Those of ordinary skul
`
`in
`
`the
`
`art having access
`
`to
`
`the
`
`teachings herein will
`
`recognize
`
`additional
`
`implementations, modifications, and examples, as well as other fields of use, which are
`
`within the scope of the present disclosure as described herein, and with respect to which
`
`the present disclosure may be ofsignificant utility.
`
`BRIEF DESCRIPTIONOF THE DRAWINGS
`
`[0016] The features, nature, and advantages of the present disclosure will become more
`
`apparent from the detailed description set forth below when taken in conjunction with
`
`the drawings in which hke reference characters identify correspondingly throughout,
`
`where dashed lines may indivate optional components or actions, and wherein:
`
`i0017] FIG.
`
`1]
`
`is a schematic diagram conceptually illustrating an example of a wireless
`
`communications system, in accordance with various aspects ofthe present disclosure,
`
`f0018} FIG. 2 is a schematic diagram conceptually illustrating carrier aggregation,
`
`in
`
`accordance with various aspects ofthe present disclosure.
`
`[8o19} FIGs. 3 and 4 are block diagrams conceptually Ulustrating aspects of a LIE and a DAT
`
`manager of the LE, in accordance with various aspects of the present disclosure.
`
`[0020] FIG.
`
`5S
`
`is a schematic diagram conceptually Ulustrating sets or tables used for HARQ
`
`payload size selection, in accordance with various aspects ofthe present disclosure.
`
`{8021} FiGs. 6 and 7 are block diagrams conceptually Mhustrating aspects of an eNB and a DAI
`
`manager of the eNB, 1p accordance with various aspects of the present disclosure.
`[0022] FIGs. 8 and 9 are flow diagrams conceptuallyillustrating examples of methods for DAI
`management in enhanced carrier aggregation, in accordance with various aspects ofthe
`
`present disclosure.
`
`DETAILED DESCRIPTION
`
`10023] The detailed description set forth below in connection with the appended drawings is
`
`intended as a description of various configurations and is not intended tc represent the
`
`only configurations in which the concepts described herein may be practiced. The
`
`detailed description includes specific details for the purpose of providing a thorough
`
`understanding of various concepts. However, it will be apparent to those skilled in the
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`

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`WO 2017/087387
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`PCT/ES2016/061978
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`5
`
`att
`
`that
`
`these concepts may be practiced without
`
`these specific details.
`
`In some
`
`instances, well known components are shown tp block diagram form in order fo avoid
`
`obscuring such concepts.
`
`In an aspect, the term “component” as used herein may be one
`
`of the parts that make up a system, may be hardware or software, and may he divided
`
`into other components.
`
`{0024]
`
`The present aspects generally relaie to downlink assignment index (DAT) management
`
`in carrier aggregation (CA), and particularly in carrier aggregation scenarios in which
`
`larger numbers of component carriers (CCs)orcells are being supported (e.¢., enhanced
`
`carrier aggregation or eCA). Throughout this disclosure the terms coniponent carmers
`and cells may be used interchangeably.
`In some implementations (e.g, in LTE Rel-12),
`
`a UE may be configured to support up to five (5} component carriers (CC) for carrier
`
`ageregation. For example, cach component carrier may be configured with up to 20
`
`MHz and may be backward compatible (the UE may therefore be configured to support
`
`up to 100 MHz).
`
`In carrier aggregation, all the component carriers - which may
`
`sometimes be referred to as cells - may operate in frequency division duplexing (FDD)
`
`or time division duplexing (TDD), or operate in a combination or mixture of FDD and
`
`TDD.
`
`In some instances, component carriers in TDD may have the same or different
`
`In addition, special subframes mayalso
`downlink (DL} and uplink (UL) configurations.
`be configured differently for different TDD component carriers.
`.
`In another aspect related to current implementations, one component carrier may be
`
`{O25
`
`configured as the primary component carrier (PCC) for the UE. The PCCis the only
`
`component carrier that
`
`is configured to carry a Physical Uplink Control Channel
`
`(PUCCH} and a common search space for the UE. All other or remaining component
`
`carriers are termed secondary component carriers (SCCs).
`
`In these implementations, noe
`
`adoption has been made of enabling PLICCH for a VE on two component carriers for
`
`carrier aggregation.
`
`In such a scheme, besides the PCC, one of the secondary
`
`component carriers or cell may carry POCCHas well. This approach is at least partially
`
`motivated by dual-conneetivity and PUCCHload balancing needs.
`
`[0026]
`
`In some cases, component carriers may not have ideal backhaul capabilities, and
`
`consequently, very tight coordination between the various component carriers may not
`
`be possible because of the limited backhaul capacity and non-negligible backhaul
`
`latency {e.g..
`
`tens of milliseconds). The concept of dual-connectivity was therefore
`
`intraduced recently (e.g., LTE Rel-12} to address the above scenario.
`
`In dual-
`
`connectivity, component carriers or cells may be partitioned into two groups,
`
`the
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`PCT/ES2016/061978
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`6
`
`primary cell group (PCG) and the secondary cell group (SCG). Each of these groups
`
`may have one or more cells in carrier aggregation.
`
`In addition, cach af these groups
`
`may have a single cell carrying PUCCH. For example, a primary cell in PCG cares
`
`PUCCHfor the PCG, and a secondary cell im SCGcarries PUCCH for the SCO,also
`
`called the pScell. The commmonsearch space is also additionally monitored in the SCG
`
`by the UE. Uplink control information (UCT) may be separately conveyed to cach
`
`group via the PUCCHin each group. Moreover, semi-static scheduling (SPS) and
`
`scheduling requests (SR) are not only supported in the PSG but are supported in the
`
`SCGas well,
`
`10027}
`
`In current efforts (e.g., LTE Rel-13).
`
`there is a push to increase the number of
`
`component carriers beyond five (5) component carriers to enable enhanced carrier
`
`ageregation (eCA).
`
`For example, PECCH on a secondary cell
`
`(SCell)
`
`for Uks
`
`supporting uplink carrier aggregation may now be possible.
`
`In addition, the physical
`
`layer Specifications for PUCCH on SCell may be developed based on the necessary
`
`mechanisms that would enable LYE carrier aggregation of up to 32 component carriers
`
`for the downlink and uplink. Such mechanisms may include enhancements to downlink
`
`control signalling for up to 32 component carriers inchiding both seli-scheduling and
`
`cross-carrier scheduling, if any, as well as enhancements to uplink control signalling for
`
`up io 32 component carriers. The enhancements to uplink control signalling may
`involve enhancemenis to support UCT feedback on PUCCH for up to 32 downlink
`
`carriers by specifying the necessary enhancements to UCT feedback signalling formats,
`
`as well as enhancements to support UCT feedback on Physical Uplink Shared Channel
`
`(PUSCH) for up to 32 downlink carriers.
`
`[0028]
`
`These efforts to increase the number of component carriers need also take into
`
`consideration the use of downlink assignment index (DAI) for HARQ feedback.
`
`In
`
`TDD, for exampie, multiple downlink (DL) subframes may be associated with a same
`
`uplink (UL) subframe for HARO feedback.
`
`In order to more efficiently provide
`
`ACE/NACK. feedback, a 2-brnt DAI may be inchuled in DL grants and UL grants in
`
`TDD. When included in the DL grant, the 2-bit DL DAI mayindicate the accumulative
`
`number of DLassignments. When inchided in the ULgrant, the 2-bit UL DAI may
`
`indicate the total number of DL assignments. A UE may, based on the indicated total
`
`DAL determine the number of ACK/NACKhits for feedback, and based on the
`
`indicated accumulative DAT, order the ACK/NACK. bits of different DL subfrarmes
`
`associated with the same UE. subframe.
`
`

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`7
`
`(0029)
`
`In TDD wrth carrier aggregation, the UL DAL may be used to indicate a maxinvum
`
`number of DL subframes scheduled mimany of the multiple component carriers bem
`
`supported. For example, when 2 component carriers are being used (Le. CCT and
`
`CC2), with DL CCT and DL CC2 beth having 4 DE subframes associated with the same
`
`ULsubframe, and when only 3 of the DL. subframes in CCI are scheduled and only 2 of
`
`the DL sublrames in CC2 are scheduled,
`
`the total DAI may indicate a value of 3,
`
`representing the maximum mumber of scheduled DL subframes in each of the two
`
`component carriers.
`
`(0030)
`
`For FDD, however, there may not be DAI involved, even under FDD with carrier
`
`ageregation. The use of DAT in FDD with carrier aggregation may be beneficial
`
`instead of counting the number of DL assignments in time
`because, for example,
`domain as in TDD, DAL in FDD may count in the component carrier-domain (e.g.,
`
`frequency-domain} reflecting the number of component carriers or codewords that are
`
`scheduled,
`
`[0032]
`
`For both FDD and TDD with carrier aggregation, when a TDD component carrier is
`
`used fo carry PUCCH (thus the TDD component carrier is the primary cell, or the
`
`primary secondary ceil), DAI may be added for DL grants and ULgrants for the FDD
`
`component carrier (as a secondary cell).
`
`In other werds, the FOD See Downlink
`
`Control Information (DCI) formats may be adapted to the TDD-like DCI formats when
`
`YDD is the primary cell or the primary secondary ecll, Similarly, a TDD Scell
`
`Downlink Control Information (DCT) formats may be adapted to the FDD-Nke DCI
`
`formats when FDD is the primarycell or the primary secondarycell.
`
`{0032}
`
`For enhanced carrier aggregation, because of the increased number of component
`carriers, DAT is to be used in both FDD and TDD componentcarriers, even if a UEhas
`
`all FDOD component carriers or when a FDD cell is the primary cell or the primary
`
`secondary cell. The manner in which DAI
`
`is to be defined for enhanced carrier
`
`aggregation has vet ta be defined. Accordingly, aspects of the present disclosure
`
`provide details of various techniques or schemes for using or managing the use of DAL
`
`in enhanced carrier aggregation. Some ofthese aspects address issues such as the
`
`introduction of total DAL in DLL grants even when accumulative DAI, which is counted
`
`in a frequency(CC)-first, time-second manner, is used. Other issues may include the
`
`number ofbits for DAI in DL grants.
`
`In one example, for accumulative DAI,
`
`instead of
`
`2-bits it may be possible to use 3 bits, 4 bits, or 3 bits, ar have the number of bits
`
`depend on the mumber of configured component carriers (e.g., 6-16 CCs, 3 bus, >16
`
`

`

`WO 2017/087387
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`PCT/ES2016/061978
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`8
`
`CCs, 4 bits),
`
`In another example, for tatal DALthe number of bits may be 2 bits or 3
`
`brs. Another issue bemg addressed by the various aspects described herein is the
`
`troduction of DAT in UL arants under FDD carrier aggregation even in cases when
`
`total DALIis alreadyintroduced in DLgrants.
`
`{0033}
`
`The techniques described herein may he ased for the wireless networks and radio
`
`technologies mentioned above as well
`
`as other wireless networks
`
`and radio
`
`technologies. Forclarity, certain aspects ofthe techniques are described belowfor LTE,
`
`and LTE termmologyis used in nnuch of the description below.
`
`[034]
`
`FIG.
`
`J
`
`3s a schematic diagram conceptually illustrating an example of a wireless
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`communications system 100,
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`im accordance with an aspect of the present disclosure.
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`The wireless conmmunications system [00 includes base stations (or cells) 105, user
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`equipment (UEs} 115, and a core network 130. One or more base stations 105 may
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`include a communications component 630 isee FIG. 6} for DAI management
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`in
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`enhanced carrier aggregation (eCA} at network device, as deseribed herein. One or
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`more UEs 115 may include a communications cornponent 330 {see FIG. 3) for DAI
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`management in eCA, as described herein. The base stations 103 may communicate with
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`the URs 115 under the contre! of a base station contraller (not shown), which may be
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`part of the core network 130 or the base stations 105 in various embodiments. The base
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`stations 105 may communicate control
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`information and/or user data with the core
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`network 130 through first backhaul Tinks 132.
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`In embodiments, the base stations 105
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`may communicate, ether directly or indirectly, with each other over second backhaul
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`links 134, which may be wired or wireless communication links.
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`The wireless
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`communications system 100 may suppert operation on multiple carriers (waveform
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`signals of different frequencies). Multi-carrier transmitters can transmit modulated
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`signals simultaneously on the multiple carriers. For example, each communication fink
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`125 may be a multi-carrier signal modulated according to the various radio technologies
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`described above. Each modulated signal may be sent on a different carrier and may
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`carry cortrol
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`information (@.g., reference signals, control charmels, etc.}, overhead
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`information, data, elc. The wireless communications system: 100 may also support
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`operation on multiple flows at the same time.
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`In some aspects, the multiple flows may
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`correspond to nruliiple wireless wide area networks (WWANSs) or cellular flows.
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`In
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`other aspects, the multiple flows may correspond to a combination of WWANSs or
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`cellar flows and wireless local area networks (WLANs) or Wi-Fi flows.
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`{0035}
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`The base stations 105 may wirelessly commmmmicate with the UEs 115 via one or more
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`4%
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`base station antennas. Each of the base stations 105 sites may provide communication
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`coverage for a respective geographic coverage area }10.
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`In some embodiments, base
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`stations 105 may be referred to as a base transceiver station, a radia base station, ar
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`access point, a radio transceiver, a basic service set (BSS), an extended service set
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`(ESS), a NodeB, eNodeB, eNB, Home NodeB, a Home eNodeB, or some othersuitable
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`terpunology. The geographic coverage area 110 for a base station 105 may be divided
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`into sectors making up only a portion of the coverage area (not shown). The wireless
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`communications system J00 may include base stations 105 of different types (e.g.
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`macra, mucro, and/or pico base stations). There may be overlapping coverage areas for
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`In general, base stations 105-a may be base stations
`technologies.
`different
`corresponding to a WWAN (e.g, LTE or UMTS macroceil, pico cell, femto cell, etc.
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`base stations).
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`it
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`is to be appreciated, however, that a single base station 105 can
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`support communications over nvultiple RATs (e.g., LTE and Wi-Fi, LTE and UMTS,
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`UMTSand Wi-Fi,ete...
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`[6036]
`
`In implementations,
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`the wireless commurucations system [00 is an LTE/LTE-A
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`network Communication system.
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`In LTE‘LTE-A network communication systems, the
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`terms evalved Node B (eNodeB or eNB} may be generally used to describe the base
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`stations 105,
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`The wireless communications system 100 may be a Heterogeneous
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`LTE/LTE-A network in which different types of eNBs provide coverage for various
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`geographical regions.
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`For example, each eNB 108 may provide communication
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`coverage for a macro cell, a pico cell, a fernto cell, and/or other tvpes of cell, A macro
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`cell may covera relatively large peographicarea (e.g., several kilometers m radius} and
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`may allow unrestricted access by UEs 115 with service subscriptiens with the network
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`provider. Apico cell may cover a relatively smaller geographic area (e.g., buildings)
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`and may allow unrestricted access by UEs {15 with service subscriptions with the
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`network provider. A femta cell may alsa cover a relatively small geographicarea (e.g.
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`a home) and, in addition to unrestricted access, may also provide restricted access by
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`WEs LIS having an association with the femto cell (e.g.,UEs 115 in a closed subseriber
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`group (CSG), UEs 115 for users m the home, and the like). An eNB 105 for a macro
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`cell may be referred to as a macro eNodeB. An eNB 105 for a pico cell may be referred
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`fo as a pico eNodeB. And, an eNB 105 for a femto cell maybe referred to as a femto
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`eNodeB or a home eNedeB. An eNB J045 may support one or multiple (e.g., two, three,
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`four, and ihe like} cells
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`10
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`{0037}
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`The core network 136 may commrnicaie with the eNBs 103 or other base stations 105
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`via first backhaul
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`links 132 (eg. Si
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`interface, ete).
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`The eNBs 105 may also
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`communicate with one another, e.u., directly or indirectly via second backhaul links 134
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`(e.g., X2 interface, etc.) and/or via the first backhaul
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`links 132 fe.g.,
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`through core
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`network 130}. The wireless communications system 100 may support synchronous or
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`asynchronous operation. For synchronous operation, the eNBs 105 may have similar
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`frame timing. and transmissions from different eNBs 10S may be approximately aligned
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`in time. For asynchronous operation, the eNBs 105 may have different frame timing,
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`and transmissions from different eNBs 105 maynot be aligned in ume. The techmques
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`described herein maybe used for either synchronous or asynchronous operations.
`
`[0038]
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`The UEs 115 may be dispersed throughout the wireless communications system 100,
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`and each LIE 115 may be stationary or mobile. A UE 115 may alse be referred io by
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`those skilled in the art as a mobile station, a subscriber station, a mobile unit, a
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`subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a
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`wireless communications device, a remote device, a mobile subscriber station, an access
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`terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, a user
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`agent, a mobile client, a client, or some other suitable terminology. A UE 11S maybea
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`cellular phone, a personal digital assistant
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`(PDA}, a wireless modem, a wireless
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`communication device, a handheld device, a tablet computer, a laptap computer, a
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`cordless phone, a wireless local loop (WLLL) station, or the like. A UE 115 maybe able
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`to communicate with macro eNBs, eNodeBRs, pico eNodeBs, femto eNodeBs, relays,
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`and the like.
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`[0039]
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`The communication imks 125 shown im the wireless communications system 100 may
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`include uplink (UL) transmissions from a UE 115 to an eNB 105, and/or downlink (DL)
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`transmissions, from an eNB 105 toa UE 115. The downlink transmissions mayalso be
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`called forward link transmissions while the uplink transmissions may also be called
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`reverse linktransmissions.
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`10040]
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`In certain aspects of the wireless communications system 100, a UE 115 may be
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`configured io support carrier aggregation (CA) with two or more eNBs 105. The eNBs
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`105 that are used for carrier aggregation may be coHocated or may be connected
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`through fast connections.
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`In either case, coordinating the aggregation of component
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`carriers (CCs) for wireless cormmunications between the UE 11S and the eNHs 105 may
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`be carried out more easily because information can be readily shared between the
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`various cells being used to perform the carrier aggregation. When the eNBs 105 that are
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`y
`used for carrier aggregation are non-collocated (e.g. far apart or do not have a bigh-
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`speed connection between them),
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`then coordinating the aggregation of component
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`Vy
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`carriers may involve additional aspects.
`
`fon4t}
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`FEG. 2 is
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`a
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`schematic diagrara conceptually ilestrating carrier aggregation,
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`in
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`accordance with aspects described herein. The aggregation may occur in a system 200
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`including an UE 1l5-a (see FIG. 1), which can communicate with an eNB 105-a (sce
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`FIG. 1} using one or more component carriers } through N (CC)}-CCx}. The eNB 105-a
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`may include a communications component 630, as described herein, fer performing
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`aspects related to various schemes for DAI management in carrier aggregation, and
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`particularly in enhanced carrer aggregation (eCA),
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`UE 115-a may include a
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`communications component 330, as described herein, for performing aspects related to
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`various sehemes for DA! management
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`in carrier aggregation, and particularly in
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`enhanced carrer aggregation,
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`In this regard, the UE 115-a supports at least a WWAN
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`radio access technology (e.g.,LTE} While only one UE i]5-a and an eNB 105-a are
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`illustrated in FIG. 2, it will be appreciated that the system 200 can include any number
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`of UEs 1 i5-a and/or eNBs 105-a.
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`In one specific example,UE Li S-a can cormmnamicate
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`with one eNB 105-a over one LYE component carrier 230 while communicating with
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`another eNB 105-a over another component carrier 230.
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`[0042]
`
`The eNB 105-4 can transmut information to the UE liS-a over forward Glownlink)
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`channels 232-1]
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`through 232-N on LTE component carners CC,
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`through CCr.
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`in
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`addition, the UE 115-a can transmit information to the eNB 105-a over reverse (uplink)
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`channels 234-1 through 234-N on LTE component carriers CC;
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`through CCy. The
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`number of component carriers supported by UE 115-a and eNB 1G5-a may be up ta 32
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`component carriers, Or more.
`
`{00-43]
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`In describing the various entities of FIG. 2, as well as other figures asseciated with
`
`the nomenclature
`for the purposes of explanation,
`some of the disclosed aspects,
`associated with a 3GPP LTE or LTE-A wireless network may be used. However, if ts ta
`be appreciated that the system 200 can operate in other networks suchas, but not limited
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`to, an OFDMA wireless network, a CDMA network, a SGPP2 CDMA2000network and
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`the like.
`
`{0044}
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`In nrulti-carrier operations, the downlink control information (DCI) messages associated
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`with different UEs 115-a may be carried on multiple component carriers, For example,
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`the D