(12) INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT)
`
`(19) World Intellectual Property Organization
`International Bureau
`
`(43) International Publication Date
`23 August 2001 (23.08.2001)
`
`
`
`PCT
`
`CACO AMTA
`
`(10) International Publication Number
`WO 01/61880 Al
`
`(51) International Patent Classification’: HO4B 1/707, 7/26
`
`[GB/US]; 530 2nd Avenue, #217, Kirkland, Washington
`98033 (US).
`
`(21) International Application Number:=PCT/JPO1/01157
`2K, 6-4,
`(74) Agent: AMANO, Hiroshi; Minemura Bldg.
`Shiba 4-chome, Minato-ku, Tokyo 108-0014 (JP).
`
`(22) International Filing Date: 19 February 2001 (19.02.2001)
`
`(25) Filing Language:
`
`English
`
`(81) Designated States (national): AU, CA, CN, JP, US.
`
`(26) Publication Language:
`
`English
`
`(84) Designated States (regional): European patent (DE, FR,
`IT).
`
`(30) Priority Data:
`0003859.6
`
`19 February 2000 (19.02.2000)
`
`GB
`
`(71) Applicant (for all designated States except US): NEC
`CORPORATION [JP/JP]; 7-1, Shiba 5-chome, Mi-
`nato-ku, Tokyo 108-8001 (JP).
`
`Published:
`
`with international search report
`before the expiration of the time limit for amending the
`claims and to be republished in the event of receipt of
`amendments
`
`(72)
`(75)
`
`Inventor; and
`Inventor/Applicant (for US only): BOLOORIAN,Majid
`
`For two-letter codes and other abbreviations, refer to the "Guid-
`ance Notes on Codes and Abbreviations" appearing at the begin-
`ning ofeach regular issue of the PCTGazette.
`
`(54) Title! METHOD FOR FREQUENCY OFFSET ESTIMATION IN A DIRECT SEQUENCE SPREAD SPECTRUM COM-
`MUNICATIONS RECEIVER
`
`<—a—>
`
`+——a-—>
`
`—————$
`PC1
`ee
`PC2
`
`(57) Abstract: A methodof estimating the difference in frequency betweenbase station transmissions received over a radio channel
`and a locally generated carrier frequency in a mobile receiver. The differential phase shifts imparted to different parts of a received
`synchronization code because of a frequency offset ofthe local reference oscillator are detected in the receiver. A series ofpartial
`correlations ofthe received synchronization code overa single transmission slot allows detection ofthe differential phase shifts. Sig-
`nal to noise ratios may be improved by meansof a series of overlapping partial correlations. The period over which the correlations
`are performed is muchless than the coherence time of the radio channel.
`
`DELL 1018
`
`INAT
`
`1/61880Al
`
`5
`
`DELL 1018
`
`1
`
`

`

`WO 01/61880
`
`PCT/JP01/01157
`
`Description
`
`Method for frequency offset estimation in a direct sequence
`
`spread spectrum communications receiver
`
`Technical Field
`
`This inventionrelates to direct sequence spread spectrum communications
`andin particular it relates to a‘method for estimating the frequency offset of
`a local signalin a mobile receiver.
`
`Background Art
`In cellular systems the timing and frequency accuracy oftransmissions from
`network basestations rely on very stable and highly accurate reference
`oscillators. In the competitive market for supply of mobile stations for
`communication with the network basestations a low cost is demandedbythe
`prospective purchasers ofmobile equipment. Therefore low cost reference
`oscillators e.g voltage controlled crystal oscillators (VCX0) wouldbe the.
`usual choice for the reference oscillator ofa mobile station such as is used in
`a wideband code division multiple access (WCDMA) network..
`
`The frequency accuracyof these low cost reference oscillators e.g. 5 parts
`per million (ppm), is very muchless than the frequency accuracy ofthe
`reference oscillators available to the basestations(e.g. 0.05ppm). The
`resulting difference in frequency between the basestation transmissions and
`the locally generated carrier frequency used for down-conversion in the
`mobile station, the so-called frequency offset, causes problems with
`synchronization. Further frequency errors can arise at the mobile station
`becauseof the Dopplershifts produced by the movements of the mobile
`
`station.
`
`2
`
`

`

`WO 01/61880
`
`PCT/JP01/01157
`
`Whenpoweris applied to a mobile station the task of synchronization with a
`basestation is initiated (initial cell search). The characteristics ofthe
`Universal Mobile Telecommunications System (UMTS) and the procedure
`for initial cell search to which the following description relates is described
`in the European Telecommunications Standards Institute (ETSI) publication
`
`TR 101 146 version 3.0.0 Universal Mobile Telecommunications System,
`
`Concept evaluation. Aswill be clear to those skilled in the art the instant
`invention is not restricted to use with the UMTS and mayalso beapplied to
`other WCDMA systems. Reference is made to US 5 982 809 to Liu which
`formspart ofthe priorart.
`|
`
`The initial cell search by the mobilestationis performed in three steps and
`the first step is the acquisition of slot synchronization to the transmissions of
`the basestation providing,through a fading path, the strongest signal at the
`receiver of the mobile station. With reference to figure 1 which is a
`schematicillustration of base station broadcast transmissions, base station
`transmissions are represented at 1, the transmission channel at 2 and the
`
`mobile station receiver at 3. Infigure 1 by way of example the transmissions
`from only two basestations (BTS1 and BTS2)are shown.
`
`These base station transmissions are not synchronized with each other and
`
`are maintained to transmit over commonfixed duration time intervals
`
`referred to as slots and commonfixed duration framing intervals referred to
`as frames. One frame comprises 15 slots. Infigure 1 the start ofa slot for
`the transmissions from BTS 2 is shown delayed from thestart of a slot for
`
`the transmissions from BTS1 byan arbitrary amount t seconds.
`
`3
`
`

`

`WO 01/61880
`
`PCT/JP01/01157
`
`The base station transmissions include a synchronization channel (SCH)
`aligned with the slot boundary and a primary common control physical
`channel (PCCPCH). The synchronization channel comprisesa primary
`synchronization code (PSC) and a secondary synchronization eas (SSC) as
`illustrated in figure 2. The code transmitted as the primary synchronization
`code (Cp)is repeatedat the beginning of each slot by all basestations.
`
`The BTS transmissionsto the receiver 3 will be affected by channel 2 and
`
`the transmissions of BTS2areillustrated as received through a 3-path
`(multipath) channel while the transmissions ofBTS1 are illustrated as
`received through a 2-path channel. Thesignals from BTS 1 and BTS2 are
`effectively summedin channel 2 before arriving at receiver 3. Correlation of
`the received signal with the expected primary synchronization cade whichis
`stored in the receiverprovides a numberofcorrelation peaks. The highest
`peak detected correspondsto that base station ofthe network (the found base
`station) to which the receiver will synchronize.
`
`The secondstep ofinitial cell search establishes frame synchronization and
`identifies the code group ofthe basestation found in step 1 (the found base
`station). The third step ofinitial cell search determines the scrambling code
`assigned to the found BS. To avoid prolixity further details regarding the
`second and thirdsteps ofthe initial cell search are not presented here and
`reference is made to ETSI publication TR 101 146 supra.
`
`It is an object ofthis invention to provide an improved method ofestimating
`the frequencyoffset in a direct sequence spread spectrum communications
`
`receiver.
`
`4
`
`

`

`WO 01/61880
`
`PCT/JP01/01157
`
`In accordancewith the invention there is provided a methodof estimating
`
`the frequency offset in a direct sequence spread spectrum communications
`receiver comprising computationofdifferences in phase imparted by down-
`conversionin the receiver to parts of a synchronization code received over a
`radio channel, said differences in phase being computed fromaseries of
`
`correlations ofparts ofthe received synchronization code with a
`synchronization code stored in the receiver, in which the period over which
`the series of correlations is performedis not greater than the length of said
`
`stored synchronization code.
`
`An example ofthe present invention will now be described with referenceto
`
`the figures in which:
`
`figure 1 is a schematicillustration ofbase station transmissions,
`
`figure 2 illustrates the composition ofbase aie transmissions,
`
`figure 3 is a flow chart illustrating the methodof carrier offset estimation,
`
`figure 3 illustrates a series ofpartial correlation periods within a single slot,
`
`figure 5 illustrates a series of overlapping partial correlation periods within a
`
`single slot.
`
`5
`
`

`

`WO 01/61880
`
`PCT/JP01/01157
`
`The implementation ofthe invention described herein is applicable to the
`initial cell search performedat a mobile station operating in the frequency
`division duplex (FDD) mode in a UMTSnetwork.
`.
`The performance of the UMTScell search can be degradedbyoffsets in the
`carrier and samplingclock frequencies. In practice, both the carrier and
`sampling clock frequenciesare derivedfrom the frequency of a reference
`oscillator (usually a VCXO). Thecarrier (f, ) and the sampling clock .
`
`frequencies am ) may be expressedas in equations (1) and (2) respectively.
`The terms k, and k, in these equations represent constants and f,is the
`reference frequency supplied by the reference oscillator ofthe mobile
`
`station.
`
`FHI XE.—savnadeanerearanx:(1)
`
`fmp = Kg Xf
`
`caseevsseteeesereveees(2)
`
`The equations(1) and (2) indicate the ways in which inaccuracies in the
`reference frequency generated by the crystal oscillator translate into the
`inaccuracies in the carrier and sampling clock frequencies. Whenexpressed
`in parts per million, the same inaccuracy will apply to each ofthe three
`frequencies, f, f,and fi,,,. For example, for a desired carrier peniieney of
`2 GHz, and a sampling clock frequency of 15.36 MHz, an foavoateey of
`1 ppm (in f,) represents offsets of 2 kHz in the carrier frequency and
`
`15.36 Hz in the sampling frequency.
`
`With regard to WCDMA cell search, the carrier frequencyoffset results in a
`continuousphasevariation ofthe received complex signal. The sampling
`clock frequency offset may cause incorrect detection ofvital system timing
`
`6
`
`

`

`WO 01/61880
`
`PCT/JP01/01157
`
`instances. Any effects of an offset in the sampling clock frequencyare
`observed only after processing of the signals in a large numberof slots. The
`phase rotation caused bythe offsets in the carrier frequency results ina
`decreasein the received ratio of the signal powerversus the noise plus
`
`interference power and as a consequence, an increase in the probability of
`instancesoffalse detection oftiming. Therefore ofets in both the carrier
`frequency and the sampling clock frequencywill result in a degradation of
`
`the performanceinall three steps ofthe UMTScell search process.
`
`Theloss ofperformance in the cell search caused by the frequency
`inaccuracies is evident during the first step of the cell search process.
`Sampling clock offsets may cause errors in detection ofthe slot boundaries
`i.e. the slot boundaries will be positioned in the wrong places.
`Ifthe error in
`locating the slot boundariesis larger than onechip period,the results
`obtained by the remainingcell search steps will also be in error. For practical
`frequency inaccuracies, however,a slippage of 1 chip caused by the
`sampling clock inaccuracies is observed over long time intervals.
`
`Consequently, the inaccuracies of the sampling clock are of secondary
`importance when comparedto the offsets in the carrier frequency. As the
`effects of an offset in the carrier frequency are observable immediately, these
`
`effects can be measured and usedto correctthe reference frequency. A
`reduction in the inaccuracy of the reference frequency will reduce the offsets
`
`in both the carrier and sampling clock frequencies also. The method
`described herein is based onthe differential phase offsets imparted to the
`received primary synchronization code atdown-conversion by errorsin the
`local oscillator frequency used for down-conversion. The resulting
`
`7
`
`

`

`WO 01/61880
`
`PCT/JP01/01157
`
`measurements of phase offset are used to correct the reference oscillator
`
`frequency.
`
`A complex basebandsignal transmitted by a base station may be represented
`
`wi
`
`ony
`JO(t)
`S,= A(t)err
`
`where A(t) and &) represent the magnitude and phaserespectively of the
`
`signal. The transmitted signal when received via a fading path can be
`
`representedas:
`
`—
`i(Aat+¢(t)+o (t))
`S, = B(t).S,.e7 See(3)
`where AQ is the carrier frequencyoffset in radians per second, ¢(f) is the
`
`random phase(in radians) due to the Dopplershift and o(@) is the random
`
`phase due to noise and interference. Variations ofthe signal envelope are
`
`represented as f(r).
`
`In the first step of the UMTScell search, the in phase (I) and quadrature (Q)
`components of the received signal are correlated with the primary
`synchronization code. Whenthe local primary synchronization codeis
`aligned with the first symbol of a received PCCPCH +SCH time-slot (i.e. at
`the slot boundary), the transmit signal may be expressedas:
`
`S|ai
`Sy MM CF cnetensannes(4):
`
`.
`
`where is aconstant. The correlation ofthe corresponding received signal
`with the local primary synchronization codestored in the receiver is shown
`
`in equation (5), where T is the correlation period.
`
`8
`
`

`

`WO 01/61880
`
`PCT/JP01/01157
`
`T
`
`C=
`
`oi
`j=;
`
`[BOM €'4 elOm#Oro)
`
`fanaa elowvendy
`
`—_
`
`Equation (5) represents the correlation between the local primary |
`synchronization code and the received signalat the slot boundaries. Asthe
`primary synchronization code is a known signal, the carrier frequency offset
`may be estimated by measuring the change in the phase ofthe received
`primary synchronization code. The effect ofthe signal component’ due to
`Doppler and noise plus interference are discussed below and for clarity are
`removed from equation 5 which may then be reduced to
`
`C= [M’-e
`
`T
`
`0
`
`vide
`ie
`4
`
`,J(Aat)
`
`e
`
`- dt
`
`evecuseevecens veseee(6)
`
`To evaluate the phase dueto thecarrier offset, the above integral may be
`evaluated over a numberofintervals (i.e. by using partial correlations). The
`differential phase ofthe results will then contain a eet whichis
`directly proportionalto the carrier frequency offset. This process is shown in
`the following equations where 2 intervals are used. An illustration ofthe use
`oftwo non-overlapping partial correlations is given also at figure 4.
`
`iE
`2,
`
`0
`
`ad
`
`ees4 elm) dt
`
`[M0? -e
`T
`ge
`[2-64 eh. a
`
`C,
`
`C, ll
`
`T 2
`
`The differential phase between the resultsis given by:
`
`9
`
`

`

`WO 01/61880
`
`PCT/JP01/01157
`
`A® =£¢,- 20, = BF speriseneevessweamcendo
`
`Thecarrier frequency offset may then be computed from:
`
`Ao =
`
`2A®
`ttt nteeseserseeeseeens(8)
`To
`By making use of N partial correlations, N —1 differential phase values may
`be obtained eachindicating a carrier frequency offsetof:
`
`_ (AD )N
`Ao = a seeaansaaaueasrnenee(9)
`where A is
`
`A® = ths ~ AC sae pede eedseeeacweceee(10)
`
`with CG, representing the i™ partial correlation.
`Multiple values ofdifferential phase can be used to estimate the carrier
`frequency offset under additive white Gaussian noisé (AWGN), multi-path
`and multi-user conditions by applying averagingto the individual results
`obtained from equation 10:
`|
`
`N-1
`
`Aa,
`=1Me beveveceeeueesessoe(11)
`The effect ofDoppler is minimized by ensuring that the differential phase
`valuesare obtained usingpartial correlation over periods which are much
`less than the coherence time ofthe channel. The coherence time is a period
`within which thereis a high degree ofcorrelation between faded signal
`samples andis approximately equalto the inverse ofthe Doppler frequency.
`
`10
`
`10
`
`

`

`WO 01/61880
`
`PCT/JP01/01157
`
`10
`
`For a mobile speed of 500 km/h and a nominalcarrier frequency of,2 GHz,
`the Doppler frequency approximates to 925 Hz. The corresponding value of
`coherence time is around 1x 10° seconds. Evaluation of differential phase
`values as described above is accomplished within the duration of a single
`PCCPCH +SCH symbolperiod(i.e. ~ 67x10° seconds), whichis muchless
`
`than the coherencetime.
`
`Phase variations due to Doppler usually may be assumedto be small and
`therefore would notsignificantly affect the computations described above.
`Improvedestimatesofthe carrier frequency offset may be obtained,
`however, by computation ofa set ofvalues for the frequency offset over a
`numberofslots. An averaging process can then be applied.
`An averaging process is shown by the equation
`
`M N-I1
`
`> 2, AV
`
`| >
`
`
`k=)_i=1
`oO=
`
`M (N ~1)
`where Aw, represents the frequency offset estimate ofthe i* correlation of
`the k" slot. / is the numberofslots used in the averaging process. The
`frequency offset is then derived from the average value taken fromthe series
`of partial correlations within each slot and over a numberofslots.
`
`Various factors affect the choice ofthe numberofpartial correlations per
`primary synchronization code to be’used in the above process. Aniincrease
`in the numberofpartial correlations in the series of correlationsresults in a
`shorter correlation period (relative to the coherence time). With shorter
`
`11
`
`11
`
`

`

`WO 01/61880
`
`PCT/JP01/01157
`
`correlation periods smaller variations ofphase due to Doppler may be
`
`expected. Use of shorter correlation periods, however, causes a drop in the
`
`detected signal powerandleads to a reduced signal to noise plus interference
`
`ratio. For reducedsignal to noise ratios the effect of AWGN and
`
`interference on the detected differential phase values becomes more severe.
`
`It has been foundthat two partial correlations per primary synchronization
`
`code are sufficient for estimates of the carrier frequency offset to be
`
`obtained.
`
`The minimum detectable frequency.offset is dependent uponthe ratio of the
`
`powersofthe signalto the noise plus interference and also on the variations
`in the signal phase due to Doppler overthepartial correlation intervals.
`Experimentalresults indicate that for a mobile station moving at 80
`kilometres per hour (km/h) the method described herein can be expected to
`detect more than 95% ofthe carrier frequency offsets and the detection rate
`
`remains above 75% for 500Km/h.
`
`For increased correlation powers overlapping betweenthepartial |
`
`correlations may be employed. By this means each of the correlations in a
`
`series of correlations include a part of the synchronization code commonto
`anotherofthe correlationsin the series of correlations. With reference to
`figure 5 two overlapping partial correlationsare illustrated as perioumied |
`within a single slot.
`In UMTSthe primary synchronization code X is of
`length 256 chips. A first partial correlation PC1 is performedwith thefirst
`(256 - a) chips and a secondpartial correlation PC2 is performed with the
`last (256-a) chips. In this series of correlations 256-2a chips are common to
`
`12
`
`12
`
`

`

`WO 01/61880
`
`PCT/JP01/01157
`
`both PCI and PC2. More generally first and second overlappingpartial
`
`correlations may be represented as
`aeT
`
`- J MP-€'4 ehdt
`,= [aede5eS.dt
`
`=
`Owing to the increase in the length of each partial correlation period the
`arrangement shown in figure 5 provides a correlation power greater than that
`obtained from the non-overlapping arrangements. The corresponding
`differential phase is given by (A@ . a. T)/X,, whereXis thetotalnumberof
`chips in the primary synchronization code, T is the duration of the primary
`synchronization codein secondsanda is the numberofchips ofthe primary
`synchronization codenotusedin the partial correlation process.
`
`Fora carrier frequency offset of1 ppm,a carrier frequency of2 GHz, and
`with a = 64 chips as shown in this example,the nominal correlation peak of
`the partial correlations will be approximately 2.5 dB less than thatprovided
`by a correlation with the ebunplets 256 chip code. The nominal differential
`phaseresulting from use of an overlap with a=64 chips is 12 dewrdes and this
`difference is sufficiently large to be detected by the algorithm of figure 3.
`
`The advantage sonkined by the useofoverlapping partial scsryetittons may
`be demonstrated by comparison ofthe above example (a=64 chips) with an
`arrangement wherethere is no overlappingofthe partial correlations. Where |
`
`13
`
`13
`
`

`

`WO 01/61880
`
`PCT/JP01/01157
`
`a = 128 chips and twopartial correlations are performed in a single slot the
`partial correlation peak will be 6 dBless than for the case ofafull
`correlation (a=0). Whenarelatively high level ofnoise plusinterferenceis
`encountered, overlappingpartial correlations can be used to increase the
`powerin a partial correlation peak thereby to avoid an unacceptable
`degradation in performance.
`
`In general, a suitable value for a will be such that the overlapping correlation
`poweris maximised while the resulting differential phase remains :within the
`range of detection ofthe system. The invention may be carried into effect by
`meansofstandard digital techniques well known in the art.
`
`14
`
`14
`
`

`

`WO 01/61880
`
`PCT/JP01/01157
`
`Claims
`
`1. A method of estimating the frequency offset inadirect sequence spread
`spectrum communicationsreceiver comprising computation of differencesin
`phase imparted by down-conversionin the receiver to parts of a
`synchronization code received over a radio channel, said differences in phase
`being computed fromaseries of correlations of parts of the received
`
`synchronization code with a synchronization code stored in the receiver, in
`which the period over which the series of correlations is performedis not
`greater than the length ofsaid stored synchronization code.
`
`2. Amethodof frequency offset estimation as in claim 1 in which each of
`
`the correlations in the series of correlations include a part of the received
`
`synchronization code commonto anotherofthecorrelationsin the series of
`
`correlations.
`
`3. A method offrequencyoffset estimation as in claims 1 and 2 iin| which
`the value ofthe output phase computed from a first series ofcorrelations iis
`summed with the values of the output phases computed from a numberof
`
`succeedingseries of correlations and the average value of the summation is
`
`used as the estimate of frequency offset.
`
`4, A.method as in any preceding claim in whichthe series of partial
`correlations is performed on a codeof length X chips and comprisesa first
`correlation periodofthe first X-a chips ofthe code and a secondcorrelation
`period ofthe last X-a chips of the code where a is a numberofchipsof said
`
`code not greater than X/2.
`
`15
`
`15
`
`

`

`WO 01/61880
`
`PCT/JP01/01157
`
`jeuuBLoWyed-Z
`
`
`
`jouueyoyyed-¢
`
`yusuely
`
`BAIBOOY
`
`,ambi-j
`
`V/4
`
`16
`
`16
`
`

`

`WO 01/61880
`
`PCT/JP01/01157
`
`a
`w
`pat
`
`3o
`
`O
`LL
`
`7
`
`SLOT
`
`ae
`2
`O
`O
`a
`
`O
`YD
`A,
`
`O
`Y
`”
`
`2/4,
`
`SUBSTITUTE SHEET (RULE26)
`17
`
`17
`
`

`

`WO 01/61880
`
`PCT/JP01/01157
`
`
`
`correlation sum
`
`par_corrcnt=0
`
`Evaluate partial
`
`
`Evaluate phase of
`partial correlation
`
`
`
`
`
`par_cor_cnt =
`
`par_corrm_cnt+1
`
`NO
`
`
`
`Evaluate N-1
`
`differential phase
`
`values
`
`
`Evaluate and save
`N-14 canier
`
`frequency error
`
`values
`
`
`
`
`slot_cnt =
`
`slot_cnt +1
`
`
`
`
`Figure 3
`
`Evaluate average
`carrier frequency
`offset using
`[M x (N-1)] values
`
`3/4
`
`18
`
`18
`
`

`

`WO 01/61880
`
`PCT/JP01/01157
`
`~—a—>
`
`~a-—>
`
`PC2
`
`PC1
`
`Figure4
`
`4/k
`
`19
`
`PC2
`
`PC1
`
`Figure5
`
`19
`
`

`

`Nilsson, M
`
`Further documents are listed in the continuation of box C.
`
`Patent family members arelisted in annex.
`
`of cited documents :
`
`® Special categories
`p
`Sones
`ia
`s
`A’ documentdefining the general state of the art which is not
`considered to be of particular relevance
`"E" earlier document but published on or after the international
`filing date
`iBa cocina which may throw doubts onpriority apron or
`which
`is cited to establish the publicationdate of another
`citation or other special reason (as specified)
`*O" documentreferring to an oral disclosure, use, exhibition or
`other means
`*P" documentpublished prior to the internationalfiling date but
`later than the priority date claimed
`Date of the actual completion of the international search
`
`26 July 2001
`Name and mailing address of the ISA
`European PatentOffice, P.B. 5818 Patentiaan 2
`NL - 2280 HV Rijswijk :
`Tel. (4+31-70) 340-2040,
`Tx. 31 651 epo ni,
`Fax: (+31-70) 340-3016
`Form POT/SA/210 (second sheet) (July 1992)
`
`*T*
`
`later document published after the internationalfiling date
`orpriorily date and not in conflict with the application but
`cited to understandthe principle or theory underlying the
`invention
`*x* document of particular relevance;the claimed invention
`cannot be considered novel or cannot be considered to
`involve an inventive step when the documentis taken alone
`*y* documentof particular relevance; the claimed invention
`cannot be consideredto involve aninventive step when the
`document is combined with one or more other such docu—
`ments, such combination being obvious to a person skilled
`in the art.
`*&* document memberof the same patent family
`Date of mailing of the international search report
`
`06/08/2001
`Authorized officer
`
`+
`
`20
`
`page 1 of 2
`
`INTERNATIONAL SEARCH REPORT
`
`ational Application No
`PCT/JP 01/01157
`
`A. CLASSIFICATION OF SUBJECT MATTER
`IPC 7
`H04B1/707
`HO4B7/26
`
`According to International Patent Classification (IPC) or to both national classification and IPC
`B. FIELDS SEARCHED
`
`Minimum documentation searched (classification system followed by classification symbols)
`IPC 7
`H04B
`
`Documentation searched other than minimum documentation to the extent that such documents are included in the fields searched
`
`Electronic data base consulted during the international search (name of data base and, where practical, search terms used)
`
`EPO-Internal, PAd, WPI Data
`
`C. DOCUMENTS CONSIDERED TO BE RELEVANT
`
`Citation of document, with indication, where appropriate, of the relevant passages
`
`WO 99 66649 A (QUALCOMM INC)
`23 December 1999 (1999-12-23)
`page 5,
`line 5 -page 6,
`line 20
`page 12,
`line 28 -page 16,
`line 8; figures
`3,4
`line 11 -page 25,
`page 23,
`1-8; figure 9
`
`line 2; claims
`
`GB 2 287 613 A (ROKE MANOR RESEARCH)
`20 September 1995 (1995-09-20)
`page 3,
`line 19 - line 42
`page 5,
`line 10 -page 6,
`12-21,28; figure 3
`
`line 48; claims
`
`-/--
`
`A X
`
`A
`
`20
`
`

`

`INTERNATIONAL SEARCH REPORT
`
` Wi
`itional Application No
`PCT/JP 01/01157
`
`C.(Continuation) DOCUMENTS CONSIDERED TO BE RELEVANT
`Citation of document, with indication,where appropriate, of the relevant passages
`
`
`
`
`
`2-4
`
`
`
`
`
`
`
`
`
`
`
`
`EP 0 892 528 A (NOKIA MOBILE PHONES LTD)
`20 January 1999 (1999-01-20)
`page 2,
`line 5 - line 20
`page 5,
`line 9 -page 6,
`1-3; figures 2,3
`
`line 14; claims
`
`Form PCT/ASA/210 (continuation of second sheet)(July 1992)
`
`214
`
`age 2 of 2
`pag
`
`21
`
`

`

`
`INTERNATIONAL SEARCH REPORT
`
` lr
`itional Application No
`
`
`Information on patent family members
`PCT/JP 01/01157
`
`Patent document
`Publication
`
`
`Patent family
`Publication
`date
`cited in search report
`
`member(s)
`date
`WO 9966649
`A
`23-12-1999
`
`
`
`GB 2287613
`
`EP 0892528
`
`A
`
`A
`
`20-09-1995
`
`20-01-1999
`
`
`
`19-06-2001
`6249539 B
`US
`
`
`05-01-2000
`5204399 A
`AU
`04-04-2001
`1088400 A
`EP
`
`
`eeeeee
`
`
`
`30-03-1999
`
`
`US
`BR
`JP
`
`6005889 A
`9802478 A
`11088229 A
`
`21-12-1999
`03-11-1999
`
`
`
`
`
`Form PCTASA/210 (patent family annex) (July 1992)
`
`22
`
`22
`
`