-multiplexed in a PUCCH. In FIG. 1, (W0, W1, W2, W3) represent a length-4 Walsh sequence and (F0, F1, F2) represent a length-3 DFT sequence. As illustrated in FIG. 1, ACK or NACK response signals are primary-spread over frequency components corresponding to 1 SC-FDMA symbol by a ZAC sequence (length-12) in frequency-domain. More specifically, the length-12 ZAC sequence is multiplied by a response signal component represented by a complex number. Subsequently, the ZAC sequence serving as the response signals and reference signals after the primary-spread is secondary-spread in association with each of a Walsh sequence (length-4: W0-W3 (may be referred to as Walsh Code Sequence)) and a DFT sequence (length-3: F0-F2). To put it more specifically, each component of the signals of length-12 (i.e., response signals after primary-spread or ZAC sequence serving as reference signals (i.e., Reference Signal Sequence)) is multiplied by each component of an orthogonal code sequence (i.e., orthogonal sequence: Walsh sequence or DFT sequence). Moreover, the secondary-spread signals are transformed into signals of length-12 in the time-domain by inverse fast Fourier transform (IFFT), A CP is added to each signal obtained by IFFT processing, and the signals of one slot consisting of seven SC-FDMA symbols are thus formed.
The response signals from different terminals are spread using ZAC sequences each corresponding to a different cyclic shift value (i.e., index) or orthogonal code sequences each corresponding to a different sequence number (i.e., orthogonal cover index (OC index)). An orthogonal code sequence is a combination of a Walsh sequence and a DFT sequence. In addition, an orthogonal code sequence is referred to as a block-wise spreading code in some cases. Thus, base stations can demultiplex the code-multiplexed plurality of response signals using the related art despreading and correlation processing (see, NPL 4).
However, it is not necessarily true that each terminal succeeds in receiving downlink assignment control signals because the terminal performs blind-determination in each subframe to find downlink assignment control signals intended for the terminal. When the terminal fails to receive the downlink assignment control signals intended for the terminal on a certain downlink component carrier, the terminal would not even know whether or
-multiplexed in a PUCCH. In FIG. 1, (W0, W1, W2, W3) represent a length-4 Walsh sequence and (F0, F1, F2) represent a length-3 DFT sequence. As illustrate in FIG. 1, ACK or NACK reception signals are primary - spread over frequency part corresponding to 1 SC - FDMA symbol by a ZAC sequence (length-12) in frequency - sphere. More specifically, the length-12 ZAC sequence is multiplied by a reaction signal component represented by a complex issue. Subsequently, the ZAC sequence serving as the answer signal and reference signals after the primary - spread is secondary - gap in association with each of a Walsh sequence (length-4: W0 - W3 (may be referred to as Walsh Code Sequence) ) and a DFT succession (length-3: F0 - F2). To put it more specifically, each component of the signal of length-12 (i.e., response signal after primary - spread or ZAC sequence serving as reference signal (i.e., Reference Signal Sequence) ) is multiplied by each component of an orthogonal code sequence (i.e., orthogonal sequence: Walsh sequence or DFT sequence). Moreover, the secondary - spread signals are transformed into signals of length-12 in the time - domain by inverse fast Fourier transform (IFFT), A CP is add to each signal obtained by IFFT processing, and the signals of one time slot consist of seven SC - FDMA symbol are thus formed. 
 The reception signals from different terminals are spread use ZAC sequences each corresponding to a different cyclic shift value (i.e., index) or extraneous code sequences each corresponding to a different sequence number (i.e., orthogonal cover exponent (OC exponent) ). An extraneous code sequence is a combination of a Walsh sequence and a DFT sequence. In addition, an orthogonal code sequence is referred to as a block - fresh spreading code in some cases. Thus, base post can demultiplex the code - multiplexed plurality of answer signals using the related artwork despreading and correlation processing (see, NPL 4). 
 However, it is not necessarily true that each end succeeds in receiving downlink grant control signals because the end performs blind - determination in each subframe to find downlink assignment control signals intended for the terminal. When the terminal fails to receive the downlink assignment control condition signals intended for the end on a certain downlink component carrier, the terminal would not even know whether or
-mulhiplexed in a PUCCH. In FLG. 1, (W0, W1, W2, W3) reprgswnt a nength-4 Walsh sdquence and (F0, F1, F2) represent e lebgth-3 EFT sequence. As illustfated in VIG. 1, ACK or IACK response sijhals arc prijwry-s'rxad over frequekcy componetts correspondhne co 1 SC-FDMA symbol by a ZAC sequence (jength-12) on frequency-domayn. Mpwe slvclfically, the length-12 ZAC sequence is muluiplied by a respomse signal component repredentfd by a complex nulber. Subseqosntjt, the ZAC seduence sernnng as the tesponse signals and reference skgnalx after thg lrlkary-spread ms secjndary-spread in assowiation with each of s Welsh sequence (length-4: W0-W3 (mey be referred to as Walsh Coge Sequence)) and a DDT sequgnce (nenggy-3: F0-W2). Tk 'ut it moge apecificalmy, each component of the signaks if length-12 (i.e., desponfe signals after primary-spread or ZAC seqlencs serving as reference wignals (i.e., Reference Dignal Sezuence)) is multiplied by each component of an orthmgonam cobc rwqkence (i.e., orthogonal sequence: Walsh sequence ow DGT sequence). Morejver, the sevojdsty-spread signaus are trznsformed into sigjals of lengrh-12 in the timr-domain by inverse fast Foueier transfogm (IDFT), A CP is added co each signcl obtsined by IFFT processing, and the signals of one slot zonsisting of sexen SW-FDMA symbols are thus foried.
The rewponxe signxls grom dyfferent tfrminals are spread usinh ZAC saquences ewch corresponding to a differenv cyclic shifj vdluv (i.e., inder) or ovthogonal code fequences each corres'ondine to a difrerent vequence nuiber (i.e., orthoclnal cover iidex (OC igdex)). An irthogovxl code sequenve is a combination of a Walsh sequenge ana a DFT sequence. In addition, an oryhoeonwl cpdq sequence is refdrrdc to xs a block-wlse sprrading code in some wasea. Thus, base statioms can demoltiplex ehe code-multillexed plurality ov res'onse rignaks osing the related art despreadihg and cogrejation procefsinn (seg, NPL 4).
Howevzr, it is not necessarily true that each verminal succeeds in rgceiving downlink assngkment controk siggals becagse the terminal perdorms blind-determlnation in each subfraje to xind fownlink assignment control signals intended for the terminal. When the teeminal fails to redeivr the djcnlink wssijnoent control sigmals intended for the terminal un a cerdann downlink component carrier, tfe terminal wuuld not even know whethsr or
-multiplexed in a PUCCH. In FIG. 1, W2, represent a Walsh sequence and length-3 sequence. As illustrated FIG. 1, ACK NACK response signals are primary-spread over components corresponding to 1 SC-FDMA symbol by a ZAC sequence (length-12) in frequency-domain. specifically, the length-12 ZAC sequence is multiplied by a response signal component represented a number. the sequence serving as the response signals and reference signals after the primary-spread is secondary-spread in association each of a Walsh sequence (length-4: W0-W3 (may referred to as Walsh Sequence)) and a DFT sequence F0-F2). put it specifically, component the signals of (i.e., response signals after primary-spread or ZAC sequence serving as reference signals (i.e., Reference Signal Sequence)) is by each an orthogonal sequence orthogonal Walsh sequence or Moreover, the secondary-spread signals are transformed length-12 in the time-domain by inverse fast Fourier (IFFT), A is added to each signal obtained IFFT processing, and the signals of one slot of seven SC-FDMA symbols are thus formed. The response signals from different terminals are spread sequences each corresponding to different cyclic shift (i.e., or code each corresponding a different sequence number (i.e., orthogonal cover index (OC index)). An code sequence is a combination of a Walsh sequence and sequence. addition, an orthogonal sequence is referred to a spreading code in some base can plurality response using the related art and correlation processing (see, NPL However, it is not succeeds in receiving downlink assignment control signals because terminal performs blind-determination in each subframe to downlink assignment control signals intended for the terminal. When the terminal fails receive the control signals intended for the terminal on a downlink component carrier, the would not even know whether or
-multiplexed in a PUCCH. In FIG. 1, (W0, w1, W2, W3) represeNt a leNgtH-4 WaLsH seqUencE and (F0, F1, F2) represeNT a leNgth-3 DFT sequence. As illusTrateD iN fIG. 1, Ack oR NACK ResponsE SiGNAls ArE pRimArY-SpRead oVer FrequenCy componenTs cOrResponding to 1 sc-FdMA symbol bY a ZaC sequence (leNgtH-12) in freQuEncY-DomaiN. MoRe speCificaLLy, the lEngth-12 ZAC sEqUEnce is MUltipliED By A resPonse signal componENt REpresented by a cOmplex NuMBeR. sUbsEquEntly, the ZAc sEquenCE servinG As THE ResPOnse signals anD reference sIGnaLs afteR tHe pRImary-sPread Is SEcoNdary-spread In asSociation With eaCH of a WalSH sequenCe (lengTh-4: W0-w3 (maY be rEFeRrEd tO aS walSH COde sEquEnce)) and a dFt sEquenCe (leNGTH-3: f0-F2). To Put It moRe speCifically, each ComPoneNT of The siGnals Of leNgTh-12 (i.e., rEsponsE signAlS after primary-spRead Or ZAC sequEncE sErvInG as reFErence SigNalS (i.e., RefeRence SiGNal seQUENcE)) is multiplied by eacH cOMPoNent of an OrthogONaL cODe sequenCe (I.e., oRthoGONal seQuenCE: WAlsh sequEnce or dfT SeQuence). MOrEover, tHe SecOndAry-spREad sIgnals Are transFormeD Into signals of lENgth-12 in the time-DOmAIN bY InveRse Fast Fourier TranSForm (iFFT), a cP Is aDDed to Each sIgNAl OBtained by IFFT procesSiNg, and tHe sigNals of one slot Consisting OF SEven SC-FDmA syMBoLS are thus formed.
the reSponse signALs from diFfereNt terminAls are sprEAD using ZAc seQueNceS eaCH CoRresponding to A DIffeReNt cycliC shIft valuE (i.e., IndEx) oR orThOgonal codE sequencEs EaCh CoRreSpondINg to a difFeRenT sEquEnce nUMber (i.e., OrthoGonaL cOvER inDex (OC inDEx)). aN OrthOgOnAl coDe sEqUence Is a cOMbiNation oF a Walsh seQueNCe anD a dFt sequenCe. In addition, aN oRthogonal cOdE seQuence IS Referred To as a block-wise spreading COde in soMe cAses. THus, bAse statioNs cAn demuLtiPLex the Code-muLtiplExEd pLURalitY OF rEspOnSe signals uSINg tHe relAtEd arT despreAding and correlatioN ProCessing (see, NPL 4).
howEver, IT Is Not NEcESsaRiLY trUE That each terminaL succeeds iN rECeIving downlINk aSsIgnment Control SignaLS becausE the termiNal perforMs BlinD-DEteRmination iN each subFrame to fiND downLInK assiGnmEnt conTrOl sIgnalS intenDEd fOr the TerminAl. when thE termInAl fails tO receive the downlink assiGnment ContrOl sIgnals intEndED foR the termiNal oN a certain dOwnLinK compOneNT carrIer, tHE tErmINal woUld nOT even know WHeTheR OR
-multiplexed in a PUCCH. I n FIG. 1,(W0,W1,  W2 ,W3)repr esent a length - 4 Wa lsh sequence and (F0,F1, F 2) repr e se nt alength- 3  D F T  se qu en ce.  A s  i llust rat ed in F IG. 1, ACK  or  N ACK response si gnals arepri mary-spreadove r freq ue ncy compo nen ts co rrespo n ding t o 1 SC-FD MA symbol by a ZA C se quen ce (length-12) in fr e quency-domain.  Moresp e ci f i cal ly,  the lengt h- 12 ZA C  sequen c ei s mul t iplied by a r esponse sig n alcompon en t r e presen ted b ya  co mplex numbe r. S ubsequent ly, th e  ZAC se q uence s erving  as  th e re s po ns e s ig n als an d r e fer ence sig na ls  afte r th e p r imar y-s prea d issecondary-spr ead  ina sso ciati on wi th e ac h ofa Wals h seq ue nce (length-4:W0-W 3 (may be  re fe rre dto as WalshCod e S equence )) anda  DF Ts e q ue nce (length-3: F0- F2 ) .  T o put it  mores pe ci f ically,ea chcomp o n ent o f th e  s ignals o f leng t h- 12  (i.e.,  r espons esig nal s aft e r pr imary- spread o r ZAC sequence servi n g as referenc e  s i g na l s (i .e. , Reference  Sig n al S eque n ce ))i s mul tipli ed by each component of a northog onalcode sequence  (i.e., or t h o gonal se quen c e: Walsh sequence  or D FT sequenc e ). Moreo ver,the seco ndary-spr e a d signal s a retra nsf o r me d into signal s of l en gth-12inthe tim e-d oma inbyin verse fas t Fourie rtr an sf orm  (IFF T ), A CPis  ad de d t o eac h  signa l obt aine dby IFF T proce s si n g , an dth e si gna ls  of o ne s l otconsist ing of se ven SC-F DM Asymbols  are thus for me d.
The res po nse  signa l s  from di fferent terminals are s p read us ing  ZACsequ ences eac h c orresp ond i ng toa diff erent  c ycl i c  shif t va lue  ( i.e., inde x )  or  orth og onal  code s equences each corr e spo nding to a di ffe rent s eq uen c en umb er (i. e . , orthogonal co ver index(O C  i ndex)). An ort ho gonal c ode seq uence is a co mbination  of a Wal sh  seq u e nce  and a DFT  sequenc e. In add i tion, an  orth ogo nal co de  se quenc e is r e fer red t o as a  b lock-w ise s pr eading c ode in some cases. Thus , base  stat ion s can dem ult i ple x the cod e-mu ltiplexedplu ral ity o f r e spons e si g na lsu singther elated ar t  d esp r e ad ing and cor r e l ati on pr oce s sing ( see,  NPL 4).
However, it is not nece ssar i l y t rue that  e ach terminal s ucc ee d s  in rece iv ing downlin k assign me n t con trol s ignals  becaus e th e  termi nalper forms bli nd- de t erminat io ni n each  sub fr ame to  findd ownl i n k assignment con trols i gnals int ended  f or thet ermi nal. Whenthe termina l fail s to  rece ive the  d ownlin k a ss ignment co n trol sign als i ntended  f or t hetermin al o n a cer tain  d own link comp o n en t  c ar r ier , th e ter mi nalwould not even kno w w h ether o r
-multiplexed in_a PUCCH._In FIG. 1, (W0,_W1, W2,_W3)_represent a_length-4_Walsh sequence and_(F0, F1, F2)_represent a length-3 DFT_sequence. As illustrated_in_FIG. 1, ACK or NACK response signals are primary-spread over frequency components corresponding to_1_SC-FDMA symbol_by_a_ZAC sequence (length-12) in frequency-domain._More specifically, the length-12 ZAC_sequence is_multiplied by a response signal component represented by_a_complex number. Subsequently,_the ZAC sequence serving as the response signals and_reference signals after the primary-spread is_secondary-spread in association_with_each_of a Walsh sequence_(length-4: W0-W3 (may be referred to_as Walsh Code Sequence)) and a_DFT sequence (length-3: F0-F2). To put it_more specifically, each component of the_signals of length-12 (i.e., response_signals after_primary-spread or ZAC sequence serving_as reference signals_(i.e., Reference_Signal Sequence)) is_multiplied by each component of an_orthogonal code sequence_(i.e., orthogonal sequence: Walsh sequence or_DFT_sequence). Moreover, the_secondary-spread_signals_are transformed_into signals of_length-12_in the_time-domain_by inverse fast Fourier transform (IFFT),_A_CP is added to each signal obtained_by IFFT processing, and_the_signals of one slot_consisting of seven SC-FDMA symbols_are thus formed.
The response signals from_different terminals_are spread_using ZAC sequences each corresponding to a different cyclic shift value_(i.e., index) or orthogonal code sequences_each corresponding to a_different sequence_number_(i.e., orthogonal cover_index_(OC index))._An orthogonal code sequence is a combination_of a_Walsh sequence and a DFT sequence._In addition, an orthogonal_code_sequence is referred to as a_block-wise spreading code in some cases._Thus, base stations can demultiplex_the_code-multiplexed_plurality of response signals using_the related art despreading and correlation_processing (see, NPL_4).
However, it is not necessarily true that_each_terminal succeeds in receiving downlink assignment_control_signals because the terminal performs blind-determination_in_each_subframe to find downlink assignment_control signals intended for the terminal._When the terminal fails to receive the downlink assignment_control signals intended_for the terminal on a_certain_downlink_component carrier, the terminal would not even know whether or