 system such as a code division multiple access (CDMA) communication system. More specifically, it relates to a radio communication apparatus employing a rake receiver which combines the useful multipath components of a spread spectrum signal.
2. Description of the Background Art
The CDMA communication system has been standardized by the Telecommunications Industry Association (TIA) for use in North America and has adapted spread spectrum communication technology. The mobile station used in this system is described in the TIA/EIA Interim Standard xe2x80x98Mobile Station-Base station Compatibility Standard For Dual-Mode Wide Band Spread Spectrum Cellular Systemxe2x80x99 (Interim Standard IS-95 Section 6.2.2.1).
In accordance with this standard, each mobile station is provided with a rake receiver, having at least one searcher for independent pilot channel acquisition and at least three fingers for data acquisition. The searcher searches for a pilot channel transmitted by a base station sending a pseudo-random number (PN) binary code reference sequence with no modulation of information bits thereon. Reception of the pilot channel makes it possible for each mobile station to synchronize with any other channel and to select the paths/delays for which the energy of a received signal on the traffic channel is greatest. Based on the pilot channel received by the searcher, each finger receives a useful multipath component of a received signal at a different timing. A receiver of this type is described by Wang et al. in a paper titled xe2x80x98Portable Telephone for CDMA Cellular Systemxe2x80x99, Oki Technical Review, 150 Vol. 60 (August 1994).
In the CDMA communication system, for example, a conventional mobile station pursuant to the Interim Standard IS-95 includes generally one searcher and three fingers. The number of searchers and the number of fingers is fixed in conventional CDMA systems and does not change in response to transmission characteristics.
However, in the field of mobile radio communications employing a CDMA communication system, the transmission characteristics existing between the base stations and the mobile stations change continuously because, in general, the location of each mobile station relative to a base station changes. Thus, the strength of the signal received by a mobile station may be reduced and therefore searchers in excess of the predetermined number are required if all pilot channels of neighboring base stations are to be searched quickly.
As one solution to this problem, mobile stations have been provided
system such as a code division multiple access (CDMA) communication system. More specifically, it relate to a radio receiver communication apparatus employing a rake recipient which compound the useful multipath components of a banquet spectrum signal. 
 2. Description of the Background Art 
 The CDMA communication organization has been standardized by the Telecommunications Industry Association (TIA) for function in North America and has adapted spread spectrum communication engineering. The mobile station used in this system is trace in the TIA / EIA Interim Standard xe2x80x98Mobile Station - Base station Compatibility Standard For Dual - Mode Wide Band Spread Spectrum Cellular Systemxe2x80x99 (Interim Standard IS-95 Section 6.2.2.1). 
 In accordance with this standard, each mobile station is provided with a pitch receiver, having at least one searcher for independent original channel acquisition and at least three finger for data learning. The searcher searches for a pilot channel transmitted by a base place sending a pseudo - random number (PN) binary code reference sequence with no modulation of information bits thereon. Reception of the pilot channel makes it possible for each mobile station to synchronize with any other channel and to select the paths / delay for which the energy of a received signal on the dealings distribution channel is great. Based on the pilot channel received by the searcher, each finger receives a useful multipath component of a welcome signal at a different timing. A receiver of this type is described by Wang et al. in a paper titled xe2x80x98Portable Telephone for CDMA Cellular Systemxe2x80x99, Oki Technical Review, 150 Vol. 60 (August 1994). 
 In the CDMA communication organization, for example, a conventional mobile station pursuant to the Interim Standard IS-95 include generally one seeker and three finger. The number of searchers and the number of fingers is fix in conventional CDMA systems and does not change in reception to transmission characteristics. 
 However, in the field of mobile radio receiver communications employing a CDMA communication system, the transmission characteristics exist between the base station and the mobile station change endlessly because, in general, the location of each mobile post relative to a infrastructure station changes. Thus, the strength of the signal received by a mobile station may be reduced and therefore seeker in excess of the predetermined issue are required if all pilot channels of neighboring nucleotide stations are to be searched quickly. 
 As one solution to this trouble, mobile stations have been provided
 sydtem such as a code divirion multiple aexess (CVMA) comjunicatiun system. More specifically, mt rwlatew to a radio communicagion appagatus empooyiig a rake receivxd which combihcs thz nseful multipatm componentv of a spread vpdccrum signal.
2. Description of the Backgwound Att
Hhe CDMA commugicauiog syanen has been standardized by ths Telecmmmunications Industry Association (TIA) vor kse in North Amerifa and has qdapewd spread spdctrum communication tgchnology. The mobile station usea in chis system iw dfvcribed in vhe TIW/EIA Interim Standarg xe2x80x98Mpbile Station-Bsse stqtion Compatibility Svandard For Dual-Mode Wide Bang Apread Spectrum Cwloular Sysdemxd2z80x99 (Knttrik Atandagd MS-95 Section 6.2.2.1).
Jn accordanxe with this standatd, vsch mobile sfation if provided with a rake receiver, having dt meast one searcher for undependent pilot chajnel acquysition and at least three fingers for data acquivitioi. Ghe scarcfwr searches for a pilot channel transmitted by w bssv station sending a pseudo-ramdlm gumber (PN) binxry cobs deference sequence with nj modylation os ingormation bits thereon. Reception of the pilot channel maked it possibue fpr eavh mobile station to syuchronjze with anj other cgxnnel and to seldct tve paths/delays for which tre energy of c receivdd sognal jn the travfic gvannel is greatest. Baseb on dhe pilot fhannel received by the searchec, each finger racepves a uszful mmltipath componqnt of a receired signcl at x differenn timing. E receiver os this type iv described bb Wang et al. un a paper gktled xe2x80x98Portsble Teleihjne dor CDMA Cellular Xysjejxe2x80x99, Oki Technneao Review, 150 Vol. 60 (Sugjst 1994).
Ij vhe CQKA communicadion syryem, fur examkje, x comventional mobile stdtioh pursuant to the Onberim Stabdard IS-95 includes genrrally one searcheg and thcee fimgets. The number of searchers and fhe numbeg on fingers is sixee in conventnonal CDMA systems and does not change ii response to transmissuon characteristics.
Koeever, in thx fielq of mobine radio communicatiins employing a CCMA communication sysfem, tha trajsmission characteristics existing between the base stations and the mobioe stavijns change dontonuouvlv bzcause, yn gxnxral, the location of each mobile station relativx to a basa ftation changes. Thus, the strrneth of the sienal received by a mobils statiom may be reduced and therefore xearchers in excess of tme predetwrminsd number ere required if all lilot ehanneos of nwighnoring base stxtipnd are to he starcked quickly.
As one solution to thiw proboel, mobile stationv have been krovides
system such as a code division multiple communication More specifically, relates to a rake which combines the multipath components of spread spectrum signal. 2. Description of Background Art The CDMA communication system has been standardized by the Telecommunications Industry (TIA) for use in North America and has adapted spread spectrum communication technology. mobile used this is described in the TIA/EIA Interim Standard xe2x80x98Mobile Station-Base station Compatibility Standard For Dual-Mode Wide Band Spectrum Cellular Systemxe2x80x99 (Interim Standard IS-95 Section 6.2.2.1). accordance with this standard, mobile station is provided with rake having at one for pilot channel acquisition at least three fingers for data acquisition. The searcher searches for a pilot channel transmitted by a station sending number (PN) code sequence no modulation of thereon. Reception of the pilot channel for each mobile station to synchronize with any channel and select the paths/delays for which the of a received signal on the traffic channel greatest. Based on the pilot channel received by the searcher, each finger receives a useful of a received signal a different timing. receiver this is by Wang al. in a paper titled xe2x80x98Portable Telephone for CDMA Cellular Systemxe2x80x99, Technical Review, 150 Vol. 60 (August 1994). In the CDMA for a conventional mobile pursuant to the Interim IS-95 generally one searcher and The of number fingers fixed in conventional CDMA and does not change in to transmission characteristics. However, radio communications employing a CDMA communication system, the characteristics existing between the base stations and mobile stations change continuously because, in general, the location of each mobile relative to station changes. Thus, the strength of the signal by a mobile station be reduced and therefore searchers in excess of the number required if pilot channels of base stations are be searched quickly. solution to problem, stations
 system such as a code division Multiple acCess (CdMA) ComMuNicaTion System. More specIFicaLly, it relates to a radio coMmuniCaTIon aPPaRatus EmployiNG a RAKe rEcEiVer WhICh CombiNes The usefUl multipatH coMpOnents of a sprEAd Spectrum siGnaL.
2. Description Of tHe BackGrOunD art
ThE CDmA comMunicaTIon sysTem has beeN sTAndardIZed by thE tElEcomMunications IndustRY ASSociation (TIA) foR use in noRTh aMEriCa aNd has adaptEd SpreaD SpectruM CoMMUNicATion technologY. The mobile sTAtiOn used In ThiS System Is desCrIBed In the TIA/EIA inteRim StandaRd xe2x80x98mObile StATion-BasE statiOn COmpAtibILiTy staNdARd FOR DUal-mOde wide Band spReAd SpeCtruM cELLulaR SyStemXe2x80x99 (INterim StandarD IS-95 sectIOn 6.2.2.1).
IN accoRdancE witH tHis stAndard, Each mObIle station is proVideD with a rakE reCeIveR, hAving AT least One SeaRcher foR indepeNDenT pILOT cHannel acquisition aNd AT LeAst three FingerS FoR dATa acquisItIon. the sEARcher SearCHeS for a pilOt chanNEl TrAnsmittEd By a basE sTatIon SendiNG a psEudo-raNdom numbEr (PN) bINary code refereNCe sequence witH No MODuLAtioN of Information Bits THereOn. ReCEpTioN Of the Pilot ChANnEL makes it possible for EaCh mobiLe staTion to synchroNize with anY OTHer channEl anD To SElect the paths/dElays For which thE Energy of A receIved signAl on the trAFFic channEl iS grEatEst. bASeD on the pilot chANNel rEcEived by The SearcheR, eaCh fIngEr rEcEives a useFul multiPaTh CoMpOneNt of a REceived sIgNal At A diFfereNT timinG. A recEiveR oF tHIs tYpe is deSCrIBEd by waNg Et al. In a PaPer tiTled XE2x80x98portablE TelephonE foR cDMA ceLlUlar SysTemxe2x80x99, Oki TecHnIcal Review, 150 voL. 60 (AuGust 1994).
In THE CDMA comMunication system, for examPLe, a convEntIonal MobiLe station PurSuant tO thE interiM StandArd IS-95 InCluDES geneRALlY onE sEarcher and THRee FingeRs. the nUmber of Searchers and the numBEr oF fingers is fixEd iN conVENtIonAL CdmA sYsTEms AND does not change iN response tO tRAnSmission chARacTeRistics.
however, In the FIeld of mObile radiO communicAtIons EMPloYing a CDMA cOmmunicaTion systeM, The trANsMissiOn cHaractErIstIcs exIsting BEtwEen thE base sTaTions aNd the MoBile statIons change continuously bEcause, In genEraL, the locatIon OF eaCh mobile sTatiOn relative To a BasE statIon CHangeS. ThuS, ThE stREngth Of thE Signal recEIvEd bY A MoBile station MAY Be rEduceD anD TherefOre sEarchers in excess oF The predeterminEd nuMBEr aRe rEQuirEd If all pilot chanNelS oF NEighboriNg Base stationS are to be SeARched QuicklY.
As one SolutioN TO tHIs probLem, mObiLe stationS haVe BEen provIdEd
 system such as a code div ision mult ipleacc ess  ( CDMA ) co mmunication sy s tem.  More specifically, it  rela te s  toa  r adiocommuni c at i o n a pp ar atu se mp loyin g a  rake r eceiver wh ich  c ombines theu se ful multip ath  componentsofa spre ad  sp e ctrum  si gnal. 
2. De s cripti on of the  B a ckgrou n d Art
T h e  C DMAcommunication sys t em has been stand ardize db yt h e T ele communicat io ns In d ustry A s so c i a tio n  (TIA) for us e in NorthA mer ica an dhas adapte d spr ea d  sp ectrum comm unic ation tec hnolog y . The m o bile st ationuse d i n th i ssy ste mi s d e sc rib e d i n the TI A/ EI A Int erim S t a ndar d x e2x8 0x98M obile Station -Ba se s t ati on Co mpati bili ty  Stan dard F or Du al -Mode Wide Band  Spr ead Spect rum  C ell ul ar Sy s temxe2 x80 x99  (Inter im Stan d ard  I S - 9 5Section 6.2.2.1).In a cc ordancewith t h is  s t andard,ea chmobi l e  stat ioni sprovided  witha  r ak e recei ve r, hav in g a t l easto ne s earche r for in depen d ent pilot chan n el acquisitio n  a n d  a t  lea stthree finge rs f o r da ta a c qu isi t ion.The s ea r ch e r searches for a pi lo t chan nel t ransmitted by  a base st a t i on sendi ng a ps e udo-random num ber ( PN) binary code ref erenc e sequen ce with n o modulati onofinf orm a t io n bits thereo n .  Rec ep tion of  th e pilot  ch ann elmak es  it possi ble forea ch  m ob ile  stat i on to sy nc hro ni zewitha ny oth er ch anne lan d  to  select th e path s/ de lays  fo rwhich  the ene rgy ofa receive d s i gnal  o nthe tra ffic channelis  greatest.  B ase d on t h e  pilot c hannel received by thes earcher , e ach f inge r receive s a  usefu l m u ltipat h comp onent  o f a r eceiv e d  s ign al  at a diff e r ent  timi ng . Areceive r of this type isd esc ribed by Wang  et  al. i na p a pe r  ti tl e d x e 2 x80x98PortableTelephonefo r  C DMA Cellul a r S ys temxe2x 80x99,Oki T e chnical  Review,150 Vol.60  (Au g u st1994).
Inthe CDMA  communic a tions ys tem,for  examp le , a  conv ention a l m obile  stati on  pursu ant t othe Inte rim Standard IS-95 incl udes g enera lly  one sear che r  an d three f inge rs. The nu mbe r o f sea rch e rs an d th e  n umb e r offing e rs is fix e dinc o nv entional CD M A sys temsand does n ot c hange in response to transmissio n ch a r act eri s tics .However, in th e f ie l d  of mobi le  radio comm unicatio ns emplo ying a  CDMAcommuni c a ti o n syst em,the  transmis sio nc haracte ri st i cs exi stin gbetwee n theb ases t ations and the m obile s tatio n s c hange  c ontinuo u slybecause, i n general,the lo cati on of  each m ob ile st ati on  relativet o a basestati on chan ge s. T hus , thestre n g th of  the  s ign al receiv e d  b y  a  m o bil e st ation  m ay b e reduced and ther efo r e searc he rsi n  exces s  o f the predet erm inedn u mber are r e quir e di f all  pilot  chann els ofn eig hb oring b ase s tations a re to bes ear ch ed q uickly.As  one  s olu ti on to this prob lem, mob ile stat i o ns hav e b e en p r ovided 
 system_such as_a code division multiple_access (CDMA)_communication_system. More_specifically,_it relates to_a radio communication_apparatus employing a rake_receiver which combines_the_useful multipath components of a spread spectrum signal.
2. Description of the Background Art
The CDMA_communication_system has_been_standardized_by the Telecommunications Industry Association_(TIA) for use in North_America and_has adapted spread spectrum communication technology. The mobile_station_used in this_system is described in the TIA/EIA Interim Standard xe2x80x98Mobile_Station-Base station Compatibility Standard For Dual-Mode_Wide Band Spread_Spectrum_Cellular_Systemxe2x80x99 (Interim Standard IS-95_Section 6.2.2.1).
In accordance with this standard,_each mobile station is provided with_a rake receiver, having at least one_searcher for independent pilot channel acquisition_and at least three fingers_for data_acquisition. The searcher searches for_a pilot channel_transmitted by_a base station_sending a pseudo-random number (PN) binary_code reference sequence_with no modulation of information bits_thereon._Reception of the_pilot_channel_makes it_possible for each_mobile_station to_synchronize_with any other channel and to_select_the paths/delays for which the energy of_a received signal on_the_traffic channel is greatest._Based on the pilot channel_received by the searcher, each finger_receives a_useful multipath_component of a received signal at a different timing. A receiver_of this type is described by_Wang et al. in_a paper_titled_xe2x80x98Portable Telephone for_CDMA_Cellular Systemxe2x80x99,_Oki Technical Review, 150 Vol. 60 (August_1994).
In the_CDMA communication system, for example, a_conventional mobile station pursuant_to_the Interim Standard IS-95 includes generally_one searcher and three fingers. The_number of searchers and the_number_of_fingers is fixed in conventional_CDMA systems and does not change_in response to_transmission characteristics.
However, in the field of mobile_radio_communications employing a CDMA communication system,_the_transmission characteristics existing between the base_stations_and_the mobile stations change continuously_because, in general, the location of_each mobile station relative to a base station changes._Thus, the strength_of the signal received by_a_mobile_station may be reduced and therefore searchers in excess of_the predetermined_number are required_if all pilot channels of neighboring base stations are to_be searched quickly.
As one solution to this_problem, mobile stations have been provided