(19) United States
`(12) Patent Application Publication (10) Pub. No.: US 2011/0317652 A1
`Kim et al.
`(43) Pub. Date:
`Dec. 29, 2011
`
`US 201 103 17652Al
`
`(54) METHOD AND APPARATUS FOR
`REPORTING CHANNEL STATE IN
`MULTLCARRIER SYSTEM
`
`(30)
`
`Foreign Application Priority Data
`
`Mar. 3, 2010
`
`(KR) ...................... .. 10-2010-0018894
`
`(76)
`
`I11Vem0r53
`
`S0 Yeon Ki111sA11Yang'5i (KR); Jae
`Hoon Chung, Anyang-si (KR);
`Yeong Hyeon Kwon, Anyang-si
`(JP); Hyun Soo K0, Anyang-si (JP)
`
`Publication Classification
`
`(51)
`
`Int‘ Cl‘
`H04W 72/08
`
`(200901)
`
`(21) App]. No‘;
`
`13/254,452
`
`(52) U.S. Cl. ...................................................... .. 370/329
`
`(22) PCT Filed:
`
`Mar. 3, 2010
`
`(57)
`
`ABSTRACT
`
`(86) PCT No‘:
`C
`§ 371 ( X1)
`’.
`(2): (4) Data
`
`PCT/KR2010/001325
`
`SeP' 1’ 2011
`.
`.
`Related U'S' Apphcatlon Data
`(60) Provisional application No. 61/157,539, filed on Mar.
`4, 2009,
`
`A method and an apparatus for reporting a channel state in a
`.
`.
`.
`.
`.
`multi-carrier system are provided. User equipment receives
`an uplink grant including an uplink resource allocation and a
`channel quality indicator (CQI) request Via one downlink
`carrier from among a plurality of downlink carriers. The user
`equipment repoits CQls for the plurality ofdownlink carriers
`Via a plurality of subframes in accordance with the CQI
`request.
`
`Su bfra me
`|—-—>|
`
`DL CC
`
`74'lIIII
`
`£5-
`
`UL cc #1 INII '
`
`L 1
`
`UL cc #1
`
`—» Time
`
`Z
`
`TELEFONAKTIEBOLAGET LM ERIC SSON AND
`
`ERICSSON INC. EX. NO. 1009
`
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`

`
`Patent Application Publication
`
`Dec. 29, 2011 Sheet 1 of 10
`
`US 2011/0317652 A1
`
`FIG. 1
`
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`

`
`Patent Application Publication
`
`Dec. 29, 2011 Sheet 2 of 10
`
`US 2011/0317652 A1
`
`FIG.2
`
`TIIIIIIJ
`L\\\\\\\\
`
`2ndSSS
`
`
`
`radioframe
`
`subframe
`
`;TIIIIIIJ
`
`v
`
`U)
`U‘)
`L/')
`-|—’
`m
`\—|
`
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`

`
`Patent Application Publication
`
`Dec. 29, 2011 Sheet 3 of 10
`
`US 2011/0317652 A1
`
`FIG. 3
`
`Control
`
`region
`
`Data
`
`region
`
`Control
`
`region
`
`Freq.
`
`Time
`
`2nd slot
`
`Subframe
`
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`
`Patent Application Publication
`
`Dec. 29, 2011 Sheet 4 of 10
`
`US 2011/0317652 A1
`
`FIG. 4
`
`CQI request on PDCCH
`
`S110
`
`
`
`
`
`CQI on PUSCH
`
`S120
`
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`

`
`Patent Application Publication
`
`Dec. 29, 2011 Sheet 5 of 10
`
`US 2011/0317652 A1
`
`OFDM symbol
`
`RS
`
`111111
`111111
`
`Data
`
`region
`
`Freq.
`
`--E-Em
`--E-
`--E-E_
`
`Time
`
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`
`Patent Application Publication
`
`Dec. 29, 2011 Sheet 6 of 10
`
`US 2011/0317652 A1
`
`FIG. 6
`
`Activation
`
`Deactivation
`
`{C KZJC
`
`DL CC #1 DL CC #2 DL CC #3 DL CC #4
`I"!
`I"!
`II
`II
`II
`II
`II
`II
`II
`II
`II
`II
`II
`II
`II
`II
`\/
`\/
`‘JL,
`‘JL,
`V
`V
`
`Referencecarrier
`
`)
`
`I
`
`________I\
`
`----II
`
`I-I_
`
`UL CC #1 UL CC #2 UL CC #3
`
`Cr;
`
`|
`
`Activation
`
`Deactivation
`
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`
`Patent Application Publication
`
`Dec. 29, 2011 Sheet 7 of 10
`
`US 2011/0317652 A1
`
` XI
`
`Z
`
`UL cc #2
`
`
`
`Time
`
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`
`Patent Application Publication
`
`Dec. 29, 2011 Sheet 8 of 10
`
`US 2011/0317652 A1
`
`FIG. 8
`
`S210
`
`S220
`
`S230
`
`CQI
`
`request
`
`CQI for
`
`DL CC #1
`
`CQI for
`
`DL CC #2
`
`n
`
`n+1 n+2 n+3 n+4 n+5 n+6 n+7 n+8 n+9
`
`—» Time
`
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`
`Patent Application Publication
`
`Dec. 29, 2011 Sheet 9 of 10
`
`US 2011/0317652 A1
`
`FIG. 9
`
`Subframe
`r-——+
`
`DL CC I%§_
`
`510
`
`UL cc #1
`
`UL cc #1
`
`
`
`‘ XI
`L 1
`
`V1!
`
`Z
`
`—— Time
`
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`
`Patent Application Publication
`
`Dec. 29, 2011 Sheet 10 of 10
`
`US 2011/0317652 A1
`
`FIG. 10
`
`
`
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`US 2011/0317652 A1
`
`Dec. 29, 2011
`
`METHOD AND APPARATUS FOR
`REPORTING CHANNEL STATE IN
`MULTI-CARRIER SYSTEM
`
`TECHNICAL FIELD
`
`carrier. If CQIs for all the carriers are reported, however, radio
`resources may be inefliciently used.
`[0010]
`It is required a method and apparatus capable of
`reporting a CQI in a multi-carrier system.
`
`[0001] The present invention relates to wireless communi-
`cation and, more particularly, to a method and apparatus for
`reporting a charmel state in a wireless communication system
`supporting multiple carriers.
`
`BACKGROUND ART
`
`are widely
`communication systems
`[0002] Wireless
`deployed in order to provide various kinds of communication
`services, such as voice and data. In general, the wireless
`communication systems are multiple access systems which
`can share available system resources (e.g., bandwidths and
`transmission power) and support communication with mul-
`tiple users. The multiple access systems may include, for
`example, a CDMA (code division multiple access) system, a
`FDMA (frequency division multiple access) system, a
`TDMA (time division multiple access) system, an OFDMA
`(orthogonal frequency division multiple access) system, and
`an SC-FDMA (single carrier frequency division multiple
`access) system.
`[0003]
`In a common wireless communication system,
`although the bandwidth ofuplink and the bandwidth of down-
`link are differently set, only one carrier is chiefly taken into
`consideration. The carrier is defined by a center frequency
`and a bandwidth. A multi-carrier system uses a plurality of
`carriers having a bandwidth smaller than the entire band-
`width.
`
`[0004] LTE (long term evolution) based on 3GPP (3rd Gen-
`eration Partnership Project) TS (Technical Specification)
`Release 8 is the leading next-generation mobile communica-
`tion standard.
`
`[0005] As disclosed in 3GPP TS 36.211 V8.5.0 (2008-12)
`“Evolved Universal Terrestrial Radio Access (E-UTRA);
`Physical Channels and Modulation (Release 8)”, physical
`channels in LTE may be divided into a PDSCH (Physical
`Downlink Shared Charmel) and a PUSCH (Physical Uplink
`Shared Channel) which are data channels and a PDCCH
`(Physical Downlink Control Channel), a PCFICH (Physical
`Control Format Indicator Channel), a PHICH (Physical
`Hybrid-ARQ Indicator Charmel), and a PUCCH (Physical
`Uplink Control Charmel) which are control channels.
`[0006] A 3GPP LTE system supports only one (i.e., one
`carrier) of {1.4, 3, 5, 10, 15, and 20} MHZ bandwidths. A
`multi-carrier system may use two carriers, each having a 20
`MHZ bandwidth, or three carriers having a 20 MHZ band-
`width, a 15 MHZ bandwidth, and a 5 MHZ bandwidth, respec-
`tively, in order to support the entire 40 MHZ bandwidth.
`[0007] A multi-carrier system has advantages in that it can
`support backward compatibility with the existing system and
`also increase the data rate through multiple carriers.
`[0008]
`In a single carrier system, control channels and data
`channels are designed based on a single carrier. In a multi-
`carrier system, however, it may be inefficient if the channel
`structure of the single carrier system is used without change.
`[0009] A CQI (Channel Quality Indicator) indicates a chan-
`nel condition. The CQI is used in order for a base station to
`schedule UEs within a cell. In order to schedule each of
`
`carriers in a multi-carrier system, a CQI is necessary for each
`
`DISCLOSURE
`
`Technical Problem
`
`[0011] The present invention provides a method and appa-
`ratus for supporting multiple carriers.
`[0012] The present invention also provides a method and
`apparatus for monitoring a control charmel in a multi-carrier
`system.
`
`Technical Solution
`
`In an aspect, a method ofreporting a charmel state in
`[0013]
`a multi-carrier system is provided. The method includes
`receiving, by an user equipment, an uplink grant including an
`uplink resource allocation and a channel quality indicator
`(CQI) request through one of a plurality of downlink carriers,
`and reporting, by the user equipment, a CQI for the plurality
`of downlink carriers over a plurality of subframes in response
`to the CQI request.
`[0014] A CQI for each of the plurality of downlink carriers
`may be reported in each of the plurality of subframes.
`[0015] The plurality of subframes may be spaced apart
`from one another at offset intervals.
`
`In another aspect, an user equipment of reporting a
`[0016]
`channel state in a multi-carrier system includes a radio fre-
`quency (RF) unit configured to transmit and receive a radio
`signal, and a processor operatively connected to the RF unit
`and configured to receive an uplink grant including an uplink
`resource allocation and a channel quality indicator (CQI)
`request through one of a plurality of downlink carriers and
`report a CQI for the plurality of downlink carriers over a
`plurality of subframes in response to the CQI request.
`
`Advantageous Effects
`
`[0017] While the structure of the existing 3GPP LTE
`remains intact, a channel condition for a plurality of carriers
`can be reported. A channel condition for a plurality of carriers
`can be reported without an additional uplink grant.
`
`DESCRIPTION OF DRAWINGS
`
`[0018]
`[0019]
`LTE.
`
`FIG. 1 shows a wireless communication system.
`FIG. 2 shows the structure of a radio frame in 3GPP
`
`FIG. 3 shows an example of an uplink subfrarne in
`[0020]
`3GPP LTE.
`
`FIG. 4 is a flowchart illustrating a method ofreport-
`[0021]
`ing an aperiodic CQI in 3GPP LTE.
`[0022]
`FIG. 5 shows CQI transmission on a PUSCH.
`[0023]
`FIG. 6 shows an example in which multiple carriers
`are operated.
`[0024]
`FIG. 7 shows an example of an operation in multiple
`carriers.
`
`illustrating a CQI report
`FIG. 8 is a flowchart
`[0025]
`method according to an embodiment ofthe present invention.
`[0026]
`FIG. 9 shows an example of a joint-coded PDCCH.
`
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`
`US 2011/0317652 A1
`
`Dec. 29, 2011
`
`FIG. 10 is a block diagram showing a wireless com-
`[0027]
`munication system to implement an embodiment of the
`present invention.
`
`MODE FOR INVENTION
`
`FIG. 1 shows a wireless communication system. A
`[0028]
`wireless communication system 10 includes one or more base
`stations (BSs) 11. The BSs 11 provide communication ser-
`vices to respective geographical regions (commonly called
`cells) 15a, 15b, and 15c. The cell may be divided into a
`number of regions (called sectors).
`[0029] A user equipment (UE) 12 may be fixed or mobile.
`The UE may be called another terminology, such as an MS
`(mobile station), an MT (mobile terminal), a UT (user termi-
`nal), an SS (subscriber station), a wireless device, a PDA
`(personal digital assistant), a wireless modem, or a handheld
`device.
`
`[0030] The BS 11 commonly refers to a fixed station which
`communicates with the UEs 12. The BS may also be called
`another terminology, such as an eNB (evolved-NodeB), a
`BTS (Base Transceiver System), or an access point.
`[0031] Hereinafter, downlink (DL) refers to communica-
`tion from a BS to a UE, and uplink (UL) refers to communi-
`cation from a UE to a BS. In downlink, a transmitter may be
`a part ofa BS, and a receiver may be a part ofa UE. In uplink,
`a transmitter may be a part of a UE, and a receiver may be a
`part of a BS.
`[0032]
`FIG. 2 shows the structure of a radio frame in 3GPP
`LTE. For the structure of the radio frame, reference can be
`made to Section 6 of 3GPP TS 36.211 V8.5.0 (2008-12)
`“Evolved Universal Terrestrial Radio Access (E-UTRA);
`Physical Channels and Modulation (Release 8)”. The radio
`frame consists of 10 subframes assigned respective indices 0
`to 9. One subframe consists of 2 slots. The time taken to
`
`transmit one subframe is called a TTI (transmission time
`interval). For example, the length of one subframe may be 1
`ms, and the length of one slot may be 0.5 ms.
`[0033] One slot may include a plurality ofOFDM (orthogo-
`nal frequency division multiplexing) symbols in the time
`domain. The OFDM symbol is used to represent one symbol
`period in the time domain because 3GPP LTE adopts
`OFDMA (orthogonal frequency division multiplexing) sym-
`bols in downlink, but not limited to a multi-access scheme or
`a name. For example, the OFDM symbol may be called
`another terminology, such as an SC-FDMA (single carrier
`frequency division multiple access) symbol or a symbol
`period.
`[0034] One slot is illustrated to include 7 OFDM symbols,
`but the number of OFDM symbols included in one slot may
`be changed according to the length of a CP (Cyclic Prefix). In
`accordance with 3GPP TS 36.211 V8.5.0 (2008-12), one
`subframe includes 7 OFDM symbols in a normal CP and
`includes 6 OFDM symbols in an extended CP.
`[0035] A resource block (RB) is a unit of resource alloca-
`tion and includes a plurality of subcarriers over one slot. For
`example, assuming that one slot includes 7 OFDM symbols in
`the time domain and the resource block includes 12 subcar-
`
`riers in the frequency domain, one resource block may
`include 7><12 resource elements (REs).
`[0036] A PSS (Primary Synchronization Signal) is trans-
`mitted through the last OFDM symbols of a first slot (i.e., the
`first slot of a first subframe (a subframe having an index 0))
`and an eleventh slot (i.e., the first slot of a sixth subframe (a
`subframe having an index 5)). The PSS is used to obtain
`
`OFDM symbol synchronization or slot synchronization and
`associated with a physical cell ID (identity). A PSC (Primary
`Synchronization Code) is a sequence used for the PSS. Three
`PSCs are included in 3GPP LTE. One of the three PSCs is
`
`transmitted as the PSS according to a cell ID. The same PSC
`is used in the last OFDM symbols of the first slot and the
`eleventh slot.
`
`[0037] An SSS (Secondary Synchronization Signal)
`includes a first SSS and a second SSS. The first SSS and the
`
`second SSS are transmitted through an OFDM symbol con-
`tiguous to an OFDM symbol through which the PSS is trans-
`mitted. The SSS is used to obtain frame synchronization. The
`SSS, together with the PSS, is used to obtain a cell ID. The
`first SSS and the second SSS use different SSCs (Secondary
`Synchronization Codes). Assuming that each of the first SSS
`and the second SSS includes 31 subcarriers, two SSCs each
`having a length of 31 are used in the first SSS and the second
`SSS, respectively.
`[0038] A PBCH (Physical Broadcast Charmel) is transmit-
`ted over the former four OFDM symbols of the second slot of
`a first subframe. The PBCH carries pieces of essential system
`information necessary for UE to communicate with a BS.
`System information transmitted through the PBCH is called
`an MIB (master information block). On the other hand, sys-
`tem information transmitted through a PDCCH (Physical
`Downlink Control Channel) is called an SIB (system infor-
`mation block).
`[0039] As disclosed in 3GPP TS 36.211V8.5.0(2008-12),
`LTE divides physical channels into a PDSCH (Physical
`Downlink Shared Channel) and a PUSCH (Physical Uplink
`Shared Channel) which are data channels and a PDCCH
`(Physical Downlink Control Charmel) and a PUCCH (Physi-
`cal Uplink Control Channel) which are control channels.
`Furthermore, downlink control channels include a PCFICH
`(Physical Control Format Indicator Charmel) and a PHICH
`(Physical Hybrid-ARQ Indicator Channel).
`[0040] Control information transmitted through a PDCCH
`is called downlink control information (DCI). The DCI may
`include the resource allocation of a PDSCH (this is also called
`a downlink grant), the resource allocation of a PUSCH (this is
`also called an uplink grant), a set of transmit power control
`command for individual UEs within a certain UE group,
`and/or the activation of the VoIP (Voice over Internet Proto-
`col).
`FIG. 3 shows an example of an uplink subframe in
`[0041]
`3GPP LTE. The uplink subframe may be divided into a con-
`trol region to which a PUCCH (Physical Uplink Control
`Charmel) carrying uplink control information is allocated and
`a data region to which a PUSCH (Physical Uplink Shared
`Charmel) carrying uplink data is allocated.
`[0042] The PUCCH for one UE is allocated as a resource
`block pair in a subframe. Resource blocks belonging to the
`resource block pair occupy different subcarriers in a first slot
`and a second slot. ‘m’ is a position index indicating a logical
`frequency domain position of the resource block pair allo-
`cated to the PUCCH within the subframe. It shows that the
`
`resource blocks having the same m value occupy different
`subcarriers in two slots.
`
`FIG. 4 is a flowchart illustrating a method ofreport-
`[0043]
`ing an aperiodic CQI in 3GPP LTE. An aperiodic CQI is a
`CQI reported by UE at the request of a BS, and a periodic CQI
`is a CQI reported in a predetermined cycle without a request
`from a BS.
`
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`US 2011/0317652 A1
`
`Dec. 29, 2011
`
`[0044] A BS sends a CQI request to UE on a PDCCH
`(S110). As disclosed in Section 5.3.3.1.1 of3GPP TS 36.212
`V8.5.0 (2008-12), the CQI request is a field of 1 bit which is
`included in a DCI format 0 that is an uplink grant for PUSCH
`scheduling. Table 1 below shows an example of fields
`included in the DCI format 0.
`
`TABLE 1
`
`FIELD NAME
`
`DESCRIPTION
`
`Uplink resource allocation
`CQI request
`
`Resource allocation for PUSCH
`Triggering of CQI report request
`
`If the bit value of the CQI request is set to ‘ 1 ’ in an
`[0045]
`nth subfrarne, the UE reports a CQI on a PUSCH in an (n+k)th
`subframe (S120). In FDD (Frequency Division Duplex), k:4.
`The PUSCH may be configured through an uplink grant
`included in the CQI request. That is, UE receives uplink
`resource allocation and a CQI request, multiplexes a CQI and
`uplink data using the uplink resource allocation, and sends
`them.
`
`FIG. 5 shows CQI transmission on a PUSCH. An
`[0046]
`‘RS’ allocated to an OFDM symbol placed at the center of a
`slot refers to a reference signal. A CQI is mapped to the upper
`part of a data region in a time-first manner. An ‘AN’ (i.e., an
`ACK/NACK signal for HARQ) and an RI (rank indicator)
`may also be transmitted on the PUSCH.
`[0047] As disclosed in Section 7.2.1 of 3GPP TS 36.213
`V8.5.0 (2008-12), in order to report the CQI, one of 6 modes
`in Table below is set as a reporting mode. The reporting mode
`is set in response to an RRC message.
`
`TABLE 2
`
`PMI Feedback Type
`
`No PMI
`
`Single PMI Multiple PMI
`
`CQI
`Feedback
`Type
`
`Wideband CQI
`Subband CQI Mode 2-0
`(UE selected)
`Subband CQI Mode 3-0 Mode 3-1
`(higher layer
`configured)
`
`Mode 1-2
`Mode 2-2
`
`[0048] The wideband CQI refers to a CQI over an entire
`band, and the subband CQI refers to a CQI over a subband of
`the entire band.
`
`[0049] A CQI report in 3GPP LTE is based on a single
`carrier system in which a downlink carrier through which a
`CQI request is transmitted and an uplink carrier through
`which a CQI is transmitted are mapped to each other in an
`one-to-one way.
`[0050] The CQI is hereinafter an index indicating a channel
`state. The CQI is also represented by an index of an MCS
`(modulation and coding) table, but may be represented using
`various formats, such as an interference level or a signal
`strength. Furthermore, the CQI may include a PMI (precod-
`ing matrix indicator) indicating an index of a precoding
`matrix and/or an RI (rank indicator) indicating a rank.
`[0051] A multi-carrier system is now described.
`[0052] A 3GPP LTE system supports a case where a down-
`link bandwidth and an uplink bandwidth are differently set.
`Here, one component carrier (CC) is a precondition for the
`case. This means that, in the state in which one CC is defined
`for each of downlink and uplink, 3GPP LTE supports a case
`
`where the downlink bandwidth is identical with or different
`
`from the uplink bandwidth. For example, the 3GPP LTE
`system may support a maximum of 20 MHZ and have differ-
`ent uplink bandwidth and downlink bandwidth, but supports
`only one CC in uplink and downlink.
`[0053] A spectrum aggregation (also called a bandwidth
`aggregation or a carrier aggregation) supports a plurality of
`CCs. The spectrum aggregation has been introduced in order
`to support an increased throughput, prevent an increase of
`costs due to the introduction of a wideband RF (radio fre-
`quency), and guarantee compatibility with the existing sys-
`tem. For example, if 5 CCs are allocated as the granularity of
`a carrier unit having a 20 MHZ bandwidth, a maximum band-
`width of 100 MHZ can be supported.
`[0054] The spectrum aggregation may be divided into a
`contiguous spectrum aggregation in which an aggregation is
`performed between consecutive carriers and a non-contigu-
`ous spectrum aggregation in which an aggregation is per-
`formed between inconsecutive carriers,
`in the frequency
`domain. The number of carriers aggregated between down-
`link and uplink may be differently set. A case where the
`number of downlink carriers is identical with the number of
`
`uplink carriers is called a symmetric aggregation, and a case
`where the number of downlink carriers is different from the
`
`number of uplink carriers is called a symmetric aggregation.
`[0055] CCs may have different siZes (i.e., bandwidths). For
`example, assuming that 5 CCs are used to configure a 70 MHZ
`bandwidth, it may be configured using a 5 MHZ carrier (car-
`rier #0)+a 20 MHZ carrier (carrier #1)+a 20 MHZ carrier
`(carrier #2)+a 20 MHZ carrier (carrier #3)+a 5 MHZ carrier
`(carrier #4).
`[0056] The term ‘multi-carrier system’ hereinafter refers to
`a system supporting multiple carriers based on the spectrum
`aggregation. In the multi-carrier system, a contiguous spec-
`trum aggregation or a non-contiguous spectrum aggregation
`or both may be used, and any one of a symmetric aggregation
`and an asymmetric aggregation may be used.
`[0057]
`FIG. 6 shows an example in which multiple carriers
`are operated. Four DL CCs (i.e., a DL CC #1, a DL CC #2, a
`DL CC #3, and a DL CC #4) and three UL CCs (i.e., an UL CC
`#1, an UL CC #2, and an UL CC #3) are illustrated, but the
`number of CCs is not limited.
`
`[0058] The DL CC #1 and the DL CC #2 ofthe four DL CCs
`are activated, which are called activated carriers. The DL CC
`#3 and the DL CC #4 are deactivated, which are called deac-
`tivated carriers. Furthermore, the UL CC #1 and the UL CC
`#2 of the three UL CCs are activated carriers, and the UL CC
`#3 thereof is an activated carrier.
`
`[0059] The activated carrier is a carrier enabling the trans-
`mission or reception of control information or a data packet.
`The activated carrier does not enable the transmission or
`
`reception of a data packet, but enables a minimum operation,
`such as signal measurement.
`[0060] The activated carrier and the activated carrier are not
`fixed, and each CC may be deactivated or activated through
`negotiations between a BS and UE. The activated carrier is
`also called a candidate carrier in that it can be activated.
`
`[0061] At least one of the activated carriers may be set as a
`reference carrier. The reference carrier is also called an
`
`anchor carrier or a primary carrier. An activated carrier which
`is not the reference carrier is called as a secondary carrier. The
`reference carrier is a carrier in which control information is
`
`TELEFONAKTIEBOLAGET LM ERIC SSON AND
`
`ERICSSON INC. EX. NO. 1009
`
`TELEFONAKTIEBOLAGET LM ERICSSON AND
`ERICSSON INC. EX. NO. 1009
`
`

`
`US 2011/0317652 A1
`
`Dec. 29, 2011
`
`transmitted on a downlink control channel (e. g., a PDCCH) or
`in which common control information for multiple carriers is
`transmitted.
`
`[0062] A mobility management message or a carrier acti-
`vation/deactivation message may be transmitted through the
`reference carrier.
`
`[0063] The reference carrier may be defined not only for
`downlink, but also for uplink. The uplink reference carrier
`may be used to send at least one ofuplink control information
`(UCI), an HARQ ACK/NACK signal, an aperiodic CQI, and
`a periodic CQI. Furthermore, the uplink reference carrier may
`be used to perform handover and perform initial access, such
`as the transmission of a random access preamble.
`[0064]
`FIG. 7 shows an example of an operation in multiple
`carriers.
`
`[0065] A BS sends a first uplink grant to UE on the first
`PDCCH 210 of a DL CC. The first uplink grant includes
`information about the resource allocation of a first PUSCH
`215 ofan UL CC #1.
`
`[0066] The BS sends a second uplink grant to the UE on the
`second PDCCH 220 of the DL CC. The second uplink grant
`includes information about the resource allocation of the first
`PUSCH 225 of an UL CC #2.
`
`[0067] The uplink grant may include a CIF (carrier indica-
`tor field) for indicating whether it is about an uplink grant for
`what UL CC. Alternatively, the UE may implicitly know an
`UL CC through the resources of a PDCCH on which the
`uplink grant is transmitted.
`illustrating a CQI report
`[0068]
`FIG. 8 is a flowchart
`method according to an embodiment of the present invention.
`[0069] A BS sends a CQI request to UE (S210). The CQI
`request may be transmitted through a PDCCH as a part of
`DCI, but may be transmitted through an RRC message.
`Uplink resource allocation, together with the CQI request,
`may also be transmitted.
`[0070] The UE sends a first CQI for a DL CC #1 on a
`PUSCH (S220). When the CQI request is received in an n-th
`subframe, the first CQI may be transmitted in an (n+k1)-th
`subframe, where k1>0. It is exemplarily shown as k1:4.
`[0071] Next, the UE sends a second CQI for a DL CC #2
`(S230). When the first CQI is transmitted in the (n+k1)-th
`subframe, the second CQI may be transmitted in an (n+k1+
`k2)-th subframe, where k2>0. It is exemplarily shown as
`k2:4.
`
`[0072] When the CQI request is triggered while the uplink
`grant for each ofthe CCs is transmitted, the uplink grant for a
`CC not requiring the uplink grant may be unnecessarily trans-
`mitted in order to request the CQI report. When one CQI
`request is triggered, a CQI for CCs is transmitted over a
`plurality of subframes without an additional uplink grant.
`[0073]
`Ifa DL CC is a deactivated carrier, a CQI may not be
`reported because an uplink grant carmot be transmitted.
`Accordingly, overhead due to the unnecessary transmission
`ofthe uplink grant can be prevented, and a CQI for a plurality
`of DL CCs can be transmitted through one uplink grant in
`order to schedule multiple carriers (the activation/deactiva-
`tion of the carriers).
`[0074] The offset (or period) k1 and/or k2 of a subframe
`through which the CQI is transmitted may be previously
`designated, but a BS may inform UE of the offset through an
`RRC message or DCI on a PDCCH.
`[0075] A CQI request for UE may be independently trig-
`gered by the CC. Alternatively, one CQI request for a plurality
`
`of CCs may be triggered. UE may receive an uplink grant,
`including a CQI request, through one or more DL CCs.
`[0076] A CQI is transmitted through two subframes (e.g.,
`an (n+k1)-th subframe and an (n+k2)-th subframe), but the
`number of subframes is not limited thereto. The CQI may be
`transmitted through P subframes or subframes which are a
`multiple of P. The number P or period of subframes through
`which the CQI is reported may be previously designated, but
`a BS may inform UE of the number P or period of subframes
`through an RRC message or DCI on a PDCCH. The sub-
`frames may be spaced apart from one another at a certain
`offset interval or at different offset intervals.
`
`[0077] Although a CQI for one DL CC is illustrated to be
`transmitted in one subframe, a CQI for a plurality of DL CCs
`may be transmitted. For example, the first CQI of the (n+k1)-
`th subframe may include a CQI for the DL CC #1 and the DL
`CC #3, and the second CQI of the (n+k1+k2)-th subframe
`may include a CQI for the DL CC #2 and the DL CC #4.
`[0078] The order ofthe DL CCs whose CQI is reported may
`be previously designated, or a BS may send the order of the
`DL CCs for reporting the CQI to UE. For example, UE may
`send a CQI for a plurality of DL CCs on the basis of a DL CC
`through which a CQI request is transmitted. Alternatively, UE
`may send CQIs according to a previously designated report
`order irrespective of a DL CC through which a CQI request is
`transmitted.
`
`[0079] The CQI reporting mode may be the same in CCs or
`may be different in CCs. For example, it is assumed that the
`DL CC #1 is an activated carrier for performing dynamic
`scheduling to UE on a subband basis and the DL CC #2 is a
`deactivated carrier. A subband CQI for the DL CC #1 is
`reported, and a wideband CQI for the DL CC #2 is reported.
`[0080] A BS may set the CQI reporting mode for each CC
`along with the CQI request or higher layer signaling.
`[0081] A UE may override the CQI reporting mode set by
`the BS. For example, the reporting mode is set so that the
`subband CQI for the DL CC #2 is reported, but if the current
`DL CC #2 has been deactivated, the UE reports the wideband
`CQI.
`[0082] As in the conventional 3GPP LTE, the CQI request
`may be a field that has 1 bit and triggers the CQI report. When
`the CQI request is received, UE reports a CQI for an activated
`carrier or a deactivated carrier or both. Here, whether a CQI
`for what DL CC will be reported may be ambiguous because
`one uplink grant exists.
`[0083] A DL CC whose CQI is reported may be determined
`using the following schemes.
`[0084] As a first embodiment, a CQI for a DL CC through
`which an uplink grant is transmitted is reported. This is
`assumed to be a reference DL CC. Here, there is a linked UL
`CC linked to the reference DL CC. The linked UL CC is an
`
`UL CC through which a PUSCH is transmitted using the
`uplink grant. There may be the linked UL CC and a plurality
`of linked DL CCs. UE reports a CQI for the plurality of DL
`CCs.
`
`For example, it is assumed that there are a DL CC
`[0085]
`#1, a DL CC #2, a DL CC #3, a DL CC #4, a DL CC #5, and
`an UL CC #1 and an UL CC #2. It is also assumed that the UL
`CC #1 is linked to the DL CC #1, the DL CC #2, and the DL
`CC #3, and the UL CC #2 is linked to the DL CC #4 and the
`DL CC #5. In the ‘link’, an uplink grant received through the
`DL CC #1, the DL CC #2, or the DL CC #3 is used by the
`linked UL CC #1. If an uplink grant including a CQI request
`
`TELEFONAKTIEBOLAGET LM ERIC SSON AND
`
`ERICSSON INC. EX. NO. 1009
`
`TELEFONAKTIEBOLAGET LM ERICSSON AND
`ERICSSON INC. EX. NO. 1009
`
`

`
`US 2011/0317652 A1
`
`Dec. 29, 2011
`
`is received through the DL CC #1, a UE sends a CQI for not
`only the DL CC #1, but also the DL CC #2 and the DL CC #3.
`[0086] The report of a CQI may be performed according to
`the sequence of physical/logical indices of DL CCs. For
`example, in the above example, a CQI for the DL CC #1
`becomes the first CQI of an (n+k1)-th subfrarne, a CQI for the
`DL CC #2 becomes the second CQI of an (n+k1+k2)-th
`subframe, and a CQI for the DL CC #3 becomes the third CQI
`of an (n+k1+k2+k3)-th subfrarne.
`[0087] As a second embodiment, a BS may inform UE of a
`report list regarding DL CCs whose CQI will be reported. The
`report list may be transmitted through part of system infor-
`mation or through higher layer signaling, such as an RRC
`message.
`the CQI request may
`[0088] As a third embodiment,
`include information about a DL CC whose CQI will be
`reported. For example, an uplink grant may be configured as
`in Table 3 below.
`
`FIELD NAME
`
`Uplink resource allocation
`CQI request index 1
`
`CQI request index 2
`
`TABLE 3
`
`DESCRIPTION
`
`Resource allocation for PUSCH
`Index offirst DL CC whose CQI will be
`reported
`Index ofsecond DL CC whose CQI will be
`reported
`
`[0089] The index of a DL CC whose CQI will be reported
`may be a physical index or a logical index. The CQI index 2
`may be a value relative to the CQI index 1.
`[0090] Alternatively, a CQI request may include the bitmap
`of DL CCs whose CQI will be reported. For example, an
`uplink grant may be configured as in Table 4 below.
`
`FIELD NAME
`
`Uplink resource allocation
`CQI request
`CQI report bitmap
`
`TABLE 4
`
`DESCRIPTION
`
`Resource allocation for PUSCH
`1 bit field to trigger CQI report
`Bitmap to indicate DL CC through which
`CQI will be reported
`
`[0091] An UL CC through which a PUSCH for an aperiodic
`CQI is transmitted may be an UL CC linked to a DL CC
`through which an uplink grant is transmitted. Alternatively,
`an UL CC through which a PUSCH for an aperiodic CQI is
`transmitted may be an UL CC for a single reference carrier or
`may be an UL CC that is additionally allocated to UE by a BS
`for CQI transmission.
`[0092]
`If an UL CC through which a PUSCH for an aperi-
`odic CQI i