CN103312372B - Frequency correcting method - Google Patents

Frequency correcting method Download PDF

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Publication number
CN103312372B
CN103312372B CN201210068638.XA CN201210068638A CN103312372B CN 103312372 B CN103312372 B CN 103312372B CN 201210068638 A CN201210068638 A CN 201210068638A CN 103312372 B CN103312372 B CN 103312372B
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frequency
group
scanning
selecting
oscillation
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CN103312372A (en
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陈威铮
彭起元
江炳宏
张豫台
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MStar Software R&D Shenzhen Ltd
MStar Semiconductor Inc Taiwan
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MStar Software R&D Shenzhen Ltd
MStar Semiconductor Inc Taiwan
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Abstract

The invention relates to a frequency correcting method, which can be used for correcting the frequency of reference oscillation signals from the initial oscillation frequency to the correction oscillation frequency. The frequency correcting method comprises the following steps that a frequency scanning section region is divided into M scanning frequencies; receiving signals are subjected to frequency reduction according to the M scanning frequencies, and in addition, M receiving signals subjected to frequency reduction are obtained; the M receiving signals subjected to frequency reduction are respectively subjected to correlation operation, and M correlation operation results are obtained; N frequency groups are distinguished from the M scanning frequencies, wherein each frequency group comprises P selecting frequencies, and the P selecting frequencies correspond to P adjacent scanning frequencies; the N frequency groups are respectively subjected to group operation, and N group operation results are obtained; selected frequency groups are selected from the N frequency groups according to N group operation results, and in addition, the correction oscillation frequency is obtained from the selected frequency groups.

Description

Frequency calibrating method
Technical field
The present invention has about a kind of frequency calibrating method, and relates to a kind of frequency calibrating method of oscillating reference signal especially.
Background technology
WCDMA (Wideband Code Division Multiple Access, referred to as WCDMA) is a kind of digitized G mobile communication.In a wcdma system, before data are sent by transmission end (base station), exhibition need be used frequently to encode (Spreading Code) by narrow frequency signal generate broadband signal, the unit giving receiving terminal wherein data after confusing through disturbing code (Scrambling Code) is again called bit (bit), and after exhibition frequently, the unit of sequence is then called chip (chip).
In order to make receiving terminal reply the fundamental frequency signal transmitted by transmission end, mobile phone must first complete synchronously with base station, otherwise receiving terminal and transmitting terminal are by because of time irreversibility, and obtains the output of noise shape waveform.WCDMA system reaches mobile phone and base station in code domain and synchronously temporal through initial cell searching procedure (initial cell search procedure).
Initial cell search refers in WCDMA system, when when mobile phone is just started shooting, all are all unknown, mobile phone need complete the action of base station search, find out the base station that signal is the strongest, mobile phone is first made to reach synchronous with base station clock pulse, find out the disturbing code that base station uses again, just correct the and base station communication of energy, and solve original fundamental frequency signal.For the ease of identifying, with f brepresent the frequency of fundamental frequency signal, and with f crepresent the frequency of carrier signal (Carrier).
Usually the oscillator (oscillator) used at mobile phone or base station end all can have some errors, cause there is carrier frequency shift (carrier frequency offset between both frequency, referred to as CFO), be also called frequency error f error.In order to make mobile phone energy normal received signal, the frequency f of the oscillating reference signal needing the local side oscillator adjusting mobile phone to produce ref, make the frequency f of oscillating reference signal refcan closer to the frequency f of carrier signal c.
When WCDMA system carries out initialization cell searching program, once Absolute Radio Frequency Channel number (absolute radio-frequency channel number, referred to as ARFCN) be selected after, next step revises the frequency of oscillating reference signal that local side oscillator produces.The permissible frequency error range of WCDMA system is approximately 3-13ppm, namely when the frequency of carrier signal is 2GHz, and the frequency f of oscillating reference signal refwith the frequency f of carrier signal cbetween have the frequency error range of 6-26kHz.
In initial cell searching procedure, the oscillating reference signal of mobile phone terminal and the carrier signal of base station is how allowed to reach Frequency Synchronization, Received signal strength being done suitable correction to produce correct receive frequency, is allow an important step of WCDMA system energy normal operation again.
Common technology, while execution initial cell is searched, first can carry out initial frequencies acquisition through a rough automatic frequency regulator (Coarse AFC).The frequency f of the oscillating reference signal that local side oscillator produces is revised according to the result of initial frequencies acquisition ref, make the frequency f of oscillating reference signal refwith the frequency f of carrier signal cbetween frequency error f error=f c-f ref, within the scope that can be adjusted to positive and negative 3ppm.
According to the planning of WCDMA system, the length of a code frame is 10ms, contains 15 time slots in each yard of frame, comprises 2560 subcodes in each time slot.In order to the object of assisting mobile phone to reach cell searching, WCDMA system provides Pnmary Synchronization passage (Primary Synchronization Channel, referred to as PSCH) and assists mobile phone to complete slot synchronization.The length of PSCH passage only has 1/10 of original slot length, and the time slot of other positions does not then comprise any information or data.Therefore, only one group of Pnmary Synchronization sequence (primary synchronizationsequence) through design is comprised in incipient 256 subcodes of each time slot.
Because all base stations all use identical PSCH sequence, and mobile phone terminal also prestores PSCH sequence, and therefore, whether mobile phone receives PSCH sequence accurately just becomes receiving terminal and use the method orienting boundary of time slot (slotboundary).Further, receiving terminal utilizes Pnmary Synchronization sequence to carry out correlation calculations (correlation calculation), and carrys out determination frequency error f according to the result of correlation calculations error.
Frequency error f between oscillating reference signal and carrier signal errorlarger, the numerical value being exported (output) by PSCH correlator (correlator) is also less.Therefore, the practice of the size exported according to PSCH correlator and determination frequency error, is often used in the initial frequencies acquisition in WCDMA system.
Refer to Figure 1A, it is that signal in WCDMA system transmits the signal transacting schematic diagram with receiving terminal.The carrier signal that the fundamental frequency signal of base station and basestation oscillator 106 produce is represented on the left of accompanying drawing.
Fundamental frequency signal will produce transmission signal utilize carrier signal to carry out increasing frequently through frequency mixer 102 after.Frequency mixer 102 can be considered as being multiplied to two signals herein, therefore, the frequency f of fundamental frequency signal bafter frequency mixer 102, just producing frequency at the output of frequency mixer 102 is f b± f csmear signal.Smear signal selects f via filter (not illustrating) b+ f cor f b-f ctransmit.Transmission signal through after transmitting through mobile communication network 10, then to be received by the antenna of mobile phone terminal by the antenna of base station.
After Received signal strength is received by mobile phone, the oscillating reference signal that the frequency mixer 101 of mobile phone terminal can utilize local side oscillator 105 to produce and frequency reducing operation is carried out to it.
In theory, the frequency f of oscillating reference signal refwith the frequency f of carrier signal ccan be equal to each other, thus can completely is replied and is obtained fundamental frequency signal in Received signal strength.But the difference in fact not so, between receiving terminal and transmission end is attributable to various variations when transport process and signal transacting.
For example, in transport process, fundamental frequency signal x (n) sent by base station may be subject to the interference (N) of noise or signal.Suppose that fundamental frequency signal is x (n), and frequency mixer 101 solutions signal out of mobile phone terminal is y (n), the signal theory that now frequency mixer 101 exports can be equivalent to the combination of fundamental frequency signal x (n) and noise N.
Except the noise in transport process, the frequency f of oscillating reference signal ref, and frequency (the carrier frequency f of the carrier signal of basestation oscillator generation c) can't be completely the same, make both frequencies there is error.Suppose the frequency f of the oscillating reference signal that local side oscillator produces reffor initial oscillation f orig(f ref=f orig), and the frequency of carrier signal is f c, then this frequency error f error(f error=f ref-f c=f orig-f c) will the y (n) separating modulation gained and go out be affected.
In order to judge the frequency error f between oscillating reference signal and carrier signal error, the practice of oscillating reference signal being carried out to frequency correction can be divided into coarse adjustment and fine setting two classes.
Wherein, be first to the frequency f of oscillating reference signal with frequency being carried out to the order of coarse adjustment refdo preliminary correction, make frequency error f errorcan first be contracted in the scope of frequency error class interval Δ f.After coarse adjustment has corrected, then again to the frequency f of oscillating reference signal refcarry out fine setting to correct.This sentences frequency rough tune as the object discussed.
Because the oscillating reference signal of local side is after frequency coarse adjustment, needs to carry out fine setting again and correct.Therefore, if during the poor effect of frequency coarse adjustment, still may occurrence frequency error excessive, the phenomenon that cannot correctly calibrate.Therefore detected ratios (detection rate) is represented follow-up when finely tuning, can be successfully for further adjustments and correct and to send as an envoy to frequency error f errorit is the ratio of 0.
The practice that common technology carries out frequency coarse adjustment is, in frequency scanning section, with different scanning frequency (sweep frequency) f itest.Wherein scanning frequency f ii-th scanning frequency of representative in frequency scanning section.
Each scanning frequency f in frequency scanning section ithere is a frequency error class interval Δ f preset to each other, according to each scanning frequency f in frequency scanning section icorrelativity calculation result y can be drawn i.Afterwards, correlativity calculation result y is recycled icomparison, and draw the maximum y of correlativity calculation result max.
Further, as correlativity calculation result y iduring for maximum, scanning frequency f corresponding thereto ifrequency error f will be made errorthe minimum value that the frequency rough timing that levels off to can reduce.
Further, with each correlativity calculation result y inumerical value compare after, first draw maximum y wherein max, just can draw correction frequency of oscillation (f accordingly ref=f i).
Below utilize its practice of equation direvation, first, represent Received signal strength r (t) with the 1st formula.
R (t)=α (t) s (t-t b) exp (j2 π f ct)+n (t), (the 1st formula)
1st formula utilizes s (t) to represent Pnmary Synchronization sequence (primary synchronization sequence), its be in a time slot (slot) before 256 chips.α (t) represents Rayleigh fading (Rayleigh fading), supposes its numerical value and frequency change irrelevant (frequency-flat) for simplicity herein.T bthe timing off-set (timingoffset) of representative between system sequence (system timing) and aerial boundary of time slot (air slot boundary); f cfor the frequency of carrier signal; And n (t) represents the summation of noise and other influences (interferences).
Then, the frequency f of oscillating reference signal is utilized through frequency mixer 101 refr (t) carries out frequency reducing to received signal.It is noted that, the frequency f of oscillating reference signal refcan according to scanning frequency f idifference and change (f ref=f i).
Further, the frequency f of oscillating reference signal refbe initial oscillation f at the beginning orig, and initial oscillation f origand be not equal to the frequency f of carrier signal c.For such problem, the use of PSCH correlator of just arranging in pairs or groups, utilizes different scanning frequency f iand test draws different correlativity calculation result.Along with scanning frequency f idifference, the frequency that collocation frequency mixer uses and carries out the oscillating reference signal of frequency reducing conversion (down conversion) to received signal also changes thereupon, and this also makes frequency mixer 101 frequency reducing Output rusults to received signal change along with the difference of scanning frequency.
Then, due to scanning frequency f ifor known, different scanning frequency f icorresponding to the correlativity calculation result that draws can learn too.2nd formula is with correlativity calculation result y irepresentative is at different sequential border option (slotboundary candidates) t min, make the situation that the output of PSCH correlator is maximum.
y i = max t m | ∫ t i t i + T r ( r ) × s * ( t - t m ) exp ( - j 2 πf i t ) dt | (the 2nd formula)
Wherein t ibe and scanning frequency f ithe initial time (starting time) of correlation.By t ican find out, as scanning frequency f iduring change, the signal being used for calculating correlation is not identical yet.T represents (integrationperiod) between integration period, is namely equivalent to a WCDMA time slot.
Can learn, under the prerequisite of Rayleigh fading α (t) for constant, as scanning frequency f according to the 2nd formula iclosest to the frequency f of carrier signal ctime, the correlativity calculation result y exported by PSCH correlator imaximum will be had.Therefore, first to each scanning frequency f iall first carry out PSCH correlation operation, judge which scanning frequency can comparatively close to the frequency (f of carrier signal according to correlativity calculation result more afterwards i≒ f c).Therefore, the frequency f of oscillating reference signal ref=f ican draw according to the 3rd formula.
f ^ i = max f i { y i } (the 3rd formula)
Once draw comparatively close to the frequency f of carrier signal cscanning frequency f iafter, common technology just can utilize the frequency f of this scanning frequency correction oscillating reference signal ref.That is the oscillating reference signal that the oscillator 107 of local side produces will by initial oscillation f ref=f origbe corrected to the aforementioned scanning frequency f corresponding to maximum correlation result ref=f i.
That is, common technology is utilizing the result of calculation estimation initial oscillation f of PSCH correlator origwith carrier frequency f cbetween frequency error f errortime, its practice is as follows:
First frequency scanning section is divided into multiple scanning frequency f i; Attempt with different scanning frequency f ias the frequency f with reference to oscillator signal ref, and observe to adopt which scanning frequency f iby the correlativity calculation result y making PSCH correlator produce ithere is maximum.
Therefore, the practice of common technology is, if a certain scanning frequency f imake the correlativity calculation result y that PSCH correlator exports iduring for maximum, just judge this scanning frequency f iin frequency scanning section, comparatively close to carrier frequency f cfrequency.Afterwards, the frequency of the oscillating reference signal just produced by local side oscillator changes this scanning frequency f into by initial oscillation i(correction frequency of oscillation).
For example, the minimum frequency in frequency scanning section and peak frequency may be defined as the frequency f with initial oscillator signal origthe scope of difference-15.4ppm to+15.4ppm.Wherein the size (step size) of each frequency scanning class interval Δ f is 1.4ppm.Therefore, with the frequency f of initial oscillator signal origcentered by-15.4ppm to+15.4ppm frequency scanning section within the scope of, if using 1.4ppm as the scope of a frequency scanning class interval Δ f time, frequency scanning section comprises (15.4*2)/1.4+1=23 scanning frequency altogether.
Refer to Figure 1B, it is the schematic diagram that common technology carries out frequency scanning side in proper order.For convenience of explanation, not complete 23 scanning frequencys of painting in formula frequency scanning section herein.This sentences different numberings and represents different scanning frequencys, and the result that each scanning frequency calculates via PSCH correlator is numbered according to same way.Such as: the first correlativity calculation result y1 drawn according to the first scanning frequency f1, the second correlativity calculation result y2 drawn according to the second scanning frequency f2, the rest may be inferred by analogy for it.
In simple terms, the practice of common technology is in frequency scanning section, with different scanning frequency f iscan.This kind is according to scanning frequency f ichange and one by one tested with checking mode, be used as oscillating reference signal frequency coarse adjustment use.
But, be detected ratios but may be made undesirable to the mode of the coarse adjustment that the correlation calculations of scanning frequency compares with the side confirmed one by one.That is, when the mode of this kind of coarse adjustment is for follow-up fine setting, frequency error might not be made to be reduced to 0.
During the correction frequency of oscillation adopting this kind of mode to estimate closest to the frequency of carrier signal, possibly the reason correctly finding out frequency error during fine setting cannot be made to be have multiple different scanning frequency f iequal correspondence produces has larger correlativity calculation result y i, or maximum extreme value all has maximum correlativity calculation result corresponding to two scanning frequencys differed greatly each other (such as: f1 and f23) simultaneously.Now just not easily judge which scanning frequency f ijust this is used to the frequency f of calibration reference oscillator signal ref.In addition, when Rayleigh fading α (t) along with the time time of change, utilize the 3rd formula estimated frequency error f erroreffect unsatisfactory.
Even can find according to analog result, when carrying out coarse adjustment in common technology mode to oscillating reference signal, frequency correction result may be made to disperse.Under this kind of situation, just be difficult to the value finding out suitable correction frequency of oscillation, therefore, common technology is in frequency scanning section, after scanning for each scanning frequency, directly to judge with correlativity calculation result and the practice adjusting the frequency of oscillating reference signal still has disappearance.
Summary of the invention
The present invention has about a kind of frequency calibrating method, be applied to an oscillating reference signal, make the frequency of this oscillating reference signal be corrected to a correction frequency of oscillation by an initial oscillation, this frequency calibrating method comprises following steps: a frequency scanning section is divided into M scanning frequency; According to this M scanning frequency, frequency reducing is carried out to a Received signal strength, and draw M the Received signal strength after frequency reducing; After respectively a correlation operation is carried out to the individual Received signal strength after frequency reducing of this M, draw M correlativity calculation result accordingly; In this M scanning frequency, distinguish N number of frequency group, wherein respectively this frequency group all comprises P selecting frequency, and this P selecting frequency corresponds to P scanning frequency adjacent in this frequency scanning section; Respectively group computing carried out to this N number of frequency group and draw N number of group operation result; And in this N number of frequency group, select a selected frequency group according to this N number of group operation result, and draw this correction frequency of oscillation from this selected frequency group.
In order to have better understanding to above-mentioned and other aspect of the present invention, preferred embodiment cited below particularly, and coordinating accompanying drawing, being described in detail below:
Accompanying drawing explanation
Figure 1A is that the signal in WCDMA system transmits the signal transacting schematic diagram with receiving terminal.
Figure 1B is the schematic diagram that common technology carries out frequency scanning side in proper order.
Fig. 2 is the preferred embodiment according to the present invention's conception, using five frequency groups as the schematic diagram on the calculating basis of frequency coarse adjustment.
Fig. 3 is the preferred embodiment according to the present invention's conception, using 23 frequency groups as the schematic diagram on the calculating basis of frequency coarse adjustment.
Fig. 4 A is according to conception of the present invention, realizes based on frequency group, draw the schematic diagram of the correction frequency of oscillation of frequency coarse adjustment by the first implementation.
Fig. 4 B is according to conception of the present invention, realizes based on frequency group, draw the schematic diagram of the correction frequency of oscillation of frequency coarse adjustment by the second implementation.
Fig. 5 is the flow chart of the frequency calibrating method of concluding according to the present invention's conception.
Fig. 6 is in frequency group, changes the ratio function schematic diagram that weight allocation uses.
Fig. 7 A is respectively by common technology and conception practice of the present invention efficiency ratio comparatively schematic diagram when the first situation that 3GPP TS 34.12 form is D.2.2.1 defined.
Fig. 7 B is respectively by common technology and conception practice of the present invention efficiency ratio comparatively schematic diagram when the second case that 3GPP TS 34.12 form is D.2.2.1 defined.
Fig. 7 C is respectively by common technology and conception practice of the present invention efficiency ratio comparatively schematic diagram when the third situation that 3GPP TS 34.12 form is D.2.2.1 defined.
Main element symbol description
Mixer 102,101,201,301,303
Basestation oscillator 106 mobile communications network 10
Local side oscillator 105 PSCH correlator 103,203,303
Mobile communications network 10 weighted sum calculates 205,305
Determining device 207,307
Embodiment
According to conception of the present invention, propose the practice on the calculating basis using frequency group as frequency coarse adjustment.Following elder generation illustrates how to apply the practice of the present invention with embodiment, and is aided with flow chart step of the present invention is described.
Refer to Fig. 2, it is the preferred embodiment according to the present invention's conception, using five frequency groups as the schematic diagram on the calculating basis of frequency coarse adjustment.
In this preferred embodiment, frequency scanning section is divided into seven scanning frequencys (f1 ~ f7).PSCH correlator is utilized to carry out correlation operation to each scanning frequency in frequency scanning section, thus the first correlativity calculation result y1 is drawn according to the first scanning frequency f1, the second correlativity calculation result y2 is drawn according to the second scanning frequency f2, closing property of third phase result of calculation y3 is drawn according to the 3rd scanning frequency f3, the 4th correlativity calculation result y4 is drawn according to the 4th scanning frequency f4, the 5th correlativity calculation result y5 is drawn according to the 5th scanning frequency f5, the 6th correlativity calculation result y6 is drawn according to the 6th scanning frequency f6, and draw the 7th correlativity calculation result y7 according to the 7th scanning frequency f7.
In this preferred embodiment, every three adjacent scanning frequencys are classified as a frequency group, and are taken as the frequency options in frequency group.Therefore, as seen from Figure 2, seven scanning frequency (f in frequency scanning section i, i=1 ~ 7) and five frequency group (G can be divided into altogether j, j=1 ~ 5).With common technology unlike, these correlativity calculation result (y1, y2, y3, y4, y5, y6, y7) drawn according to scanning frequency (f1, f2, f3, f4, f5, f6, f7) can't directly be used to compare, and can through after ranking operation, more further with frequency group G jbased on unit, compare according to each frequency group G jthe weighted sum operation result drawn.
For example, the scanning frequency in Fig. 2 is divided into five frequency groups (G1, G2, G3, G4, G5), wherein each frequency group G jall represent comprised scanning frequency f with braces i.In this preferred embodiment, suppose each frequency group G jall each self-contained three selecting frequencies (F1, F2, F3).Certainly, frequency group G jnumber (N) and the selecting frequency number (P) that comprises of each frequency group, the design of equal adaptive system and changing.
Frequency group G jin selecting frequency can according to by low and high serial number.In order to separate at each frequency group G jinterior selecting frequency numbering, this sentences F j(j=1,2,3) distinguish each selecting frequency in same frequency scanning group, and with f i(i=1,2,3,4,5,6,7) represent the scanning frequency in whole frequency scanning section.
The first selecting frequency F1 that first frequency group G1 comprises, the second selecting frequency F2, the 3rd selecting frequency F3, correspond respectively to the first scanning frequency f1 in frequency scanning section, the second scanning frequency f2 and the 3rd scanning frequency f3.
The first selecting frequency F1 that second frequency group G2 comprises, the second selecting frequency F2, the 3rd selecting frequency F3, correspond respectively to the second scanning frequency f2 in frequency scanning section, the 3rd scanning frequency f3 and the 4th scanning frequency f4.
The first selecting frequency F1 that 3rd frequency group G3 comprises, the second selecting frequency F2, the 3rd selecting frequency F3, correspond respectively to the 3rd scanning frequency f3 in frequency scanning section, the 4th scanning frequency f4 and the 5th scanning frequency f5.
The first selecting frequency F1 that 4th frequency group G4 comprises, the second selecting frequency F2, the 3rd selecting frequency F3, correspond respectively to the 4th scanning frequency f4 in frequency scanning section, the 5th scanning frequency f5 and the 6th scanning frequency f6.
The first selecting frequency F1 that 5th frequency group G5 comprises, the second selecting frequency F2, the 3rd selecting frequency F3, correspond respectively to the 5th scanning frequency f5 in frequency scanning section, the 6th scanning frequency f6 and the 7th scanning frequency f7.
Conclude aforementioned explanation can find, the selecting frequency (F1, F2, F3) that each frequency group (G1, G2, G3, G4, G5, G6, G7) comprises will corresponding to scanning frequency (f1, f2, f3, f4, f5, f6, f7) by low and high sequentially.
Such as: the selecting frequency (F1, F2, F3) that first frequency group G1 comprises is continuous three scanning frequencys (f1, f2, f3) headed by the first scanning frequency f1; The selecting frequency (F1, F2, F3) that second frequency group G2 comprises is continuous three scanning frequencys (f2, f3, f4) headed by the second scanning frequency f2.The selecting frequency (F1, F2, F3) that all the other each frequency groups comprise also has identical characteristic.
Moreover, according to the scanning frequency corresponding to each frequency group (G1, G2, G3, G4, G5, G6, G7), each frequency group is carried out to the ranking operation of correlativity calculation result.With this preferred embodiment, the correlativity calculation result (Y1, Y2, Y3) that three selecting frequencies (F1, F2, F3) that the weight (w1, w2, w3) that just distribution three is different gives comprising according to frequency group draw.
Such as: correspond to the correlativity calculation result Y1 drawn according to the first selecting frequency F1 in frequency group with the first weight w1; The correlativity calculation result Y2 drawn according to the second selecting frequency F2 in frequency group is corresponded to the second scanning frequency weight w2; And, the correlativity calculation result Y3 drawn according to the 3rd selecting frequency F3 in frequency group is corresponded to the 3rd scanning frequency weight w3.
Therefore, in this preferred embodiment, the numbering of the selecting frequency in weight, frequency group, and the corresponding relation between the correlativity calculation result corresponding with selecting frequency can be represented as: (w1, F1, Y1), (w2, F2, Y2), (w3, F3, Y3).The numerical value of weighting weight here can elasticity define, such as: the second weight w2 is maximum, and the first weight and the 3rd weight equal (w1=w3) etc.
According to conception of the present invention, will for each frequency group G jinterior selecting frequency F kthe correlativity calculation result Y drawn k, with the weighting weight w of correspondence kcarry out corresponding weighted sum computing.Drawing each frequency group G jcorresponding weighted sum operation result SY jafter, find out the selected frequency group wherein with maximum.Wherein, j represents the numbering of each frequency group, and k represents numbering corresponding with each selecting frequency in frequency group.
For Fig. 2, corresponding to each frequency group, draw weighted sum operation result SY jcan be defined as: SY j=w1*Y1+w2*Y2+w3*Y3, wherein j=1,2,3,4,5.
Certainly, the number of the selection frequency that frequency group comprises also may be different, therefore, and weighted sum operation result SY jdefinition mode also can change thereupon.
Suppose that the number of the scanning frequency in frequency scanning section still maintains shown in Fig. 2 (f1 ~ f7), but when each frequency group changes into and comprises four selecting frequency (F1, F2, F3, F4), four frequency scanning groups (G1, G2, G3, G4) can be drawn, and each frequency scanning group G jweighted sum operation result (SY corresponding to (j=1 ~ 4) j, j=1,2,3,4) can be represented as according to the weighting of each scanning frequency and correlativity calculation result: SY j=w1*Y1+w2*Y2+w3*Y3+w4*Y4.
Wherein Y 1represent basis and frequency group G jthe first interior selecting frequency F 1corresponding scanning frequency and the first selecting frequency correlativity calculation result, the Y that draw 2represent basis and frequency group G jthe second interior selecting frequency F 2corresponding scanning frequency and the second selecting frequency correlativity calculation result, the Y that draw 3represent basis and frequency group G jthe 3rd interior selecting frequency F 3corresponding scanning frequency and the 3rd selecting frequency correlativity calculation result that draws, Y 4represent basis and frequency group G jthe 4th interior selecting frequency F 4corresponding scanning frequency and the 4th selecting frequency correlativity calculation result that draws.
Same, when frequency group comprises four selecting frequency (F1, F2, F3, F4), the actual scanning frequency comprised of each frequency group, also has different combinations by according to the selecting frequency of each frequency group from the different corresponded manner between scanning frequency.Such as: the scanning frequency corresponding to selecting frequency (F1, F2, F3, F4) in first frequency group G1 is (f1, f2, f3, f4), and the scanning frequency corresponding to selecting frequency (F1, F2, F3, F4) in second frequency group G5 is (f2, f3, f4, f5), repeat no more herein.
From the above, in the preferred embodiment shown in Fig. 2, for each selecting frequency that each frequency group comprises, utilize SY k=w j* Y 1+ w 2* Y2+w 3* Y 3be weighted summation computing, wherein j=1,2,3,4,5.
Therefore, the correlativity calculation result (y1, y2, y3) that the scanning frequency (f1, f2, f3) corresponding to the selecting frequency of first frequency group G1 draws draws the first ranking operation summation SY1 further; The correlativity calculation result (y2, y3, y4) that scanning frequency (f2, f3, f4) corresponding to the selecting frequency of second frequency group G2 draws draws the second ranking operation summation SY2 further; The correlativity calculation result (y3, y4, y5) that scanning frequency (f3, f4, f5) corresponding to the selecting frequency of the 3rd frequency group G3 draws draws the 3rd ranking operation summation SY3 further; The correlativity calculation result (y4, y5, y6) that scanning frequency (f4, f5, f6) corresponding to the selecting frequency of the 4th frequency group G4 draws draws the 4th ranking operation summation SY4 further; And the correlativity calculation result (y5, y6, y7) that the scanning frequency (f5, f6, f7) corresponding to the selecting frequency of the 5th frequency group G5 draws draws the 5th ranking operation summation SY5 further.
The account form of these ranking operation summations corresponding to frequency group can be expressed as:
According to the first ranking operation summation SY1 drawn first frequency group G1, wherein SY1=w1*y1+w2*y2+w3*y3;
According to the second ranking operation summation SY2 drawn second frequency group G2, wherein SY2=w1*y2+w2*y3+w3*y4;
According to the 3rd ranking operation summation SY3 drawn the 3rd frequency group G3, wherein SY3=w1*y3+w2*y4+w3*y5;
According to the 4th ranking operation summation SY4 drawn the 4th frequency group G4, wherein SY4=w1*y4+w2*y5+w3*y6; And,
According to the 5th ranking operation summation SY5 drawn the 5th frequency group G5, wherein SY5=w1*y5+w2*y6+w3*y7.
Then, compare the numerical value of these ranking operation summations, select the person that wherein has greatest measure, and using the frequency group corresponding to this maximum weighted computing sum value as selected frequency group.
Suppose that the comparative result after according to ranking operation summation is: when the first ranking operation summation SY1 has maximum, just using first frequency group G1 as selected frequency group, and using the scanning frequency corresponding to the center selecting frequency in first frequency group G1 as correction frequency of oscillation.In like manner, if according to the comparative result after ranking operation summation be: when the numerical value of the second ranking operation summation SY2 is the maximum in all ranking operation summation, just using the scanning frequency corresponding to the center selecting frequency in second frequency group G2 as correction frequency of oscillation.
Subsidiary one carry be, in this preferred embodiment, the selecting frequency number comprised due to each frequency group is three (F1, F2, F3), therefore center selecting frequency is positioned at the second middle selecting frequency F2, but, the number of the selecting frequency comprised along with scanning group is different, and the numbering of the selecting frequency corresponding to the selecting frequency of center also may be different.
For example, when scanning frequency group Gj comprises five selecting frequencies, just with the 3rd selecting frequency F placed in the middle 3corresponding scanning frequency is as center selecting frequency.Moreover, when scanning frequency group Gj comprises four scanning frequencys, then with the second selecting frequency F placed in the middle 2with the 3rd selecting frequency F 3the mean value of corresponding scanning frequency is as correction frequency of oscillation.The practice of remaining scanning frequency number also can be analogized according to this.
Hold, the present invention proposes a kind of frequency calibrating method, and the frequency be applied to reference to oscillator signal is corrected to correction frequency of oscillation by initial oscillation.For Fig. 2, the frequency calibrating method that this preferred embodiment adopts can be summarized as following steps:
Frequency scanning section is divided into 7 scanning frequencys (f1, f2, f3, f4, f5, f6, f7); Carry out frequency reducing to received signal according to 7 scanning frequencys, and draw 7 Received signal strength after frequency reducing; After respectively correlation operation is carried out to 7 Received signal strength after frequency reducing, draw 7 correlativity calculation result (y1, y2, y3, y4, y5, y6, y7) accordingly; In 7 scanning frequencys, distinguish 5 frequency groups (G1, G2, G3, G4, G5), wherein respectively this frequency group all comprises 3 adjacent scanning frequencys; Respectively group's computing carried out to 5 frequency groups (G1, G2, G3, G4, G5) and draw 5 group's operation results (SY1, SY2, SY3, SY4, SY5); And select a selected frequency group in 5 frequency groups (G1, G2, G3, G4, G5) according to 5 group's operation results, and draw correction frequency of oscillation in the scanning frequency comprised from selected frequency pool group.
In order to illustrate further conception of the present invention, below utilizing Fig. 3 that a preferred embodiment is described in addition, illustrating that the present invention is if how frequency pool group G is as drawing the basis revising frequency of oscillation, draws the detected ratios preferably frequency coarse adjustment practice.
For the ease of comparing with common technology, in figure 3, same with Figure 1B to utilize 1.4ppm as frequency scanning class interval Δ f.Difference is then that frequency scanning section is divided into 31 scanning frequencys, and therefore, the scope of frequency scanning section herein can be larger compared with the frequency scanning section of common technology.
Further relatively can find, the frequency scanning section of Figure 1B is (1.4*11=15.4) in positive and negative 11 the frequency scanning class interval Δ f of initial oscillation.That is, scanning frequency can between (initial oscillation-15.4ppm) to (initial oscillation+15.4ppm).On the other hand, the frequency scanning section of Fig. 3 A is (1.4*15=21) in positive and negative 15 the frequency scanning class interval Δ f of initial oscillation.That is, scanning frequency can between (initial oscillation-21ppm) to (initial oscillation+21ppm).
Can learn referring to aforesaid explanation, the present invention is based on frequency group, and select the center selecting frequency of frequency group as correction frequency of oscillation, therefore, the scanning frequency (such as: f1, f7 etc., the selecting frequency number that comprises of video frequency group and different) being positioned at edge in frequency scanning section just can not become selected for revising frequency of oscillation.Also therefore, if the gap of wishing to revise between frequency of oscillation and initial oscillation is when the scope of-15.4ppm to 15.4ppm, then to be in fact used as the scope of frequency scanning section then larger compared with the tolerance frequency range of-15.4ppm to 15.4ppm in the present invention.
Refer to Fig. 3, it is according to the preferred embodiment of the present invention's conception, using 23 frequency groups as the schematic diagram on the calculating basis of frequency coarse adjustment.In this preferred embodiment, frequency scanning section is divided into M (M=31) individual scanning frequency.Time compared with previous preferred embodiment, if when the scope of frequency scanning section maintains identical, if when the scanning frequency number comprised is more, relatively represent frequency level less apart from Δ f.
In this preferred embodiment, suppose that each frequency group contains P (P=9) individual selecting frequency, these selecting frequencies correspond to the adjacent scanning frequency (adjacent frequencies) of in frequency scanning section nine.This sentences F1 ~ F9 to represent nine selecting frequencies in arbitrary frequency group.The 5th selecting frequency F5 wherein in frequency group is the center selecting frequency in frequency group, and remaining selecting frequency (F1, F2, F3, F4, F6, F7, F8, F9) is treated as subordinate selecting frequency.Certainly, during practical application, the number of the selecting frequency that frequency group comprises is not as limit.
Moreover aforementioned correlativity calculation result respectively corresponding to this scanning frequency is respectively: the first selecting frequency correlativity calculation result Y1, the second selecting frequency correlativity calculation result Y2, the 3rd selecting frequency correlativity calculation result Y3, the 4th selecting frequency correlativity calculation result Y4, the 5th selecting frequency correlativity calculation result Y5, the 6th selecting frequency correlativity calculation result Y6, the 7th selecting frequency correlativity calculation result Y7, the 8th selecting frequency correlativity calculation result Y8, the 9th selecting frequency correlativity calculation result Y9.
After drawing whole correlativity calculation result, according to the order of each scanning frequency in each frequency scanning group, provide each selecting frequency correlativity calculation result in each frequency group a ranking operation weight (weighting) (w1, w2, w3, w4, w5, w6, w7, w8, w9).
Namely with the first ranking operation weight w 1corresponding to the first selecting frequency correlativity calculation result Y1 in each frequency group, with the second ranking operation weight w 2corresponding to the second selecting frequency correlativity calculation result Y2 in each frequency group, the rest may be inferred by analogy for it.Thus, the weighted sum operation result SY as the 4th formula can just be obtained i.
SY i = Σ j = 1 o y j × w j (the 4th formula)
Wherein w jrepresent correlativity calculation result y jcorresponding weight.
Due to the output y of correlator ithe parameter of a normal distribution (normally distributedrandom variable) can be utilized to be similar to, particularly when its signal noise ratio (signal to noise power ratio, referred to as SNR) is larger time.In other words, due to the output y of correlator jroughly with exp (-((y 1-E [y 1]) 2+ ...+(y j-E [y j]) 2+ ...+(y o-E [y o]) 2)) proportional.Therefore, can according to different scanning frequency f icalculating, and find out and make weighted sum operation result for the scanning frequency f of maximum i.
The mode of correction frequency of oscillation that the present invention is used for estimating is according to maximum weighted computing summation and the scanning frequency of correspondence.That is, as frequency group G jcorresponding ranking operation summation SY jnumerical value larger time, represent selecting frequency that this group comprises more close to the actual frequency of carrier signal.Therefore, estimate that the correction frequency of oscillation drawn belongs to the scanning frequency had in the frequency group of maximum weighted sum.Just maximum likelihood estimator (maximum likelihood estimator) is represented with the 5th formula herein.
f ^ o = max f i { SY i } (the 5th formula)
According to aforementioned explanation, the present invention utilize the conception of frequency group can by Fig. 2,3 explanation learn, then utilize Fig. 4 A, 4B to illustrate below further and realize the practice of above-mentioned conception.
Refer to Fig. 4 A, it is according to conception of the present invention, realizes based on frequency group, draw the schematic diagram of the correction frequency of oscillation of frequency coarse adjustment by the first implementation.
Received signal strength carries out frequency reducing via frequency mixer 201 with oscillating reference signal, and the frequency f of oscillating reference signal refwill by initial oscillation f ref=f origbe adjusted to and revise frequency of oscillation f ref=f i'.
Afterwards, frequency mixer 201 is utilized to export the result of frequency reducing to PSCH correlator 203.Because frequency scanning section is divided into M scanning frequency, therefore changing oscillating reference signal is this M scanning frequency, and is used for respectively carrying out frequency reducing to received signal, can draw M the Received signal strength after frequency reducing altogether.
Then, for each Received signal strength after frequency reducing, after carrying out related operation by PSCH correlator, M correlativity calculation result is drawn.Then distinguish N number of frequency group according to this M correlativity calculation result, wherein respectively this frequency group all comprises P selecting frequency, and this P selecting frequency is by selecting the individual adjacent scanning frequency of P in frequency scanning section.And, according to the division of frequency group, and respectively group computing (such as: weighted sum computing 205) carried out to this N number of frequency group and draw N number of group operation result.
Finally in N number of frequency group, select a selected frequency group according to this N number of group operation result again, and draw correction frequency of oscillation from selected frequency pool group.Namely compare with the result of weighted sum computing, after judging to draw the frequency group with maximum weighted total value by determining device 207, using this frequency group as selected frequency group, and with reference to the frequency f of oscillator signal refbe modified to the center selecting frequency in selected frequency group.
Refer to Fig. 4 B, it is according to conception of the present invention, realizes based on frequency group, draw the schematic diagram of the correction frequency of oscillation of frequency coarse adjustment by the second implementation.In this implementation, further provide data storage element, and the time of wait-receiving mode signal can be reduced, and be also minimized for the power consumption switching radio frequency (radio frequency, referred to as RF) module.
In simple terms, the step of frequency reducing is divided into two stages by the second preferred embodiment, carries out respectively through frequency mixer 301 and frequency mixer 302.
First utilize frequency mixer 301 to carry out frequency reducing to received signal, the mode of its frequency reducing utilizes initial oscillation to carry out frequency reducing to received signal, draws an initial down-scaled signals through frequency mixer 301.
After drawing initial down-scaled signals, data storage element 309 is stored.Because initial down-scaled signals is stored, the follow-up test signal that can utilize further again does the frequency reducing action of second degree to initial down-scaled signals.Because initial down-scaled signals is stored in data storage element 309 with the form of numerical digit, allow follow-up calculating time, by the mode of numerical digit, directly can carry out correlation operation to the Received signal strength through down conversion process.
That is, be used for carrying out the frequency mixer 302 of second time frequency reducing in Fig. 4 B, PSCH correlator 303, weighted sum calculate 305, determining device 307 is all carry out in digital status (digital domain).
Then, then utilize the frequency-splitting of the M between each scanning frequency and initial oscillation (that is, each frequency scanning class interval) respectively and frequency reducing is carried out to initial down-scaled signals, and then drawing M the Received signal strength after frequency reducing.
When utilizing test signal to carry out frequency reducing to initial down-scaled signals, the frequency of test signal also changes along with the change of frequency scanning class interval at every turn, now just control data storage element 309, makes it again provide the content of previously stored initial down-scaled signals.
That is, according to scanning frequency f ichange, frequency reducing process is divided into two stages by this kind of implementation, and the first stage directly carries out frequency reducing to received signal with initial oscillator signal; Second stage is then with the difference between different scanning frequencys and initial oscillator signal, initial down-scaled signals is done to the frequency reducing of second degree.The result of calculation of second degree of frequency reducing will be output to PSCH correlator 203.
Because the flow process of carrying out correlation operation for the result after each frequency reducing is all similar with the first implementation, no longer describe in detail herein.
In brief, in the second implementation, Received signal strength is first with initial oscillation f reffrequency reducing (down-convert) is carried out to this Received signal strength and draws initial down-scaled signals.When Received signal strength is after frequency reducing (downconversion), just initial down-scaled signals is stored.Namely the signal of several WCDMA time slot is recorded in buffering area that data storage element provides.That is the second implementation carries out frequency reducing to each sweep signal in the mode of numerical digit, PSCH correlation calculations, weighted sum calculate, and determination frequency error, and then significantly improve overall processing speed.
Subsidiary one carries, and the record adopted according to the second implementation also plays (record-and-replay) mode, if obtain a reliable correlativity calculation result y ineed to use the many time slots in Received signal strength, these time slots can be divided into multiple section (segments), and are recorded respectively and replay.In addition, along with the change of Received signal strength, the content stored by buffering area also can by the signal update of other sections.
To use the Received signal strength of 30 time slots, 30 time slots can be divided into multiple section by the second implementation, be stored in memory, just can reuse the signal of each section.That is, Received signal strength is recorded in buffering area (buffer) inner, can for different scanning frequencys by repeat playing.Because Received signal strength is stored and after carrying out frequency reducing, carry out computing in the mode of numerical digit during follow-up use, its processing speed significantly improves.
It is noted that no matter whether adopt data storage element, aforementioned two kinds of realization sides are when carrying out correlation calculations selecting scanning frequency, and it selects the mode of scanning frequency can choose from M scanning frequency according to a predefined procedure.Wherein predefined procedure arranges the mode of scanning frequency may be increase progressively to choose order, successively decrease and choose order, random selecting order (interleaved) etc.
The advantage adopting this kind of random selecting order can reduce the impact of channel change (channel variation) for correlation calculations, make the result of correlation calculations more accurate.For example, 9 selecting frequencies in same frequency scanning group just can utilize F 1, F 5, F 9, F 2, F 6..., F 8order choose.
Conclude aforesaid explanation, bearing calibration proposed by the invention can be summarized as following step and flow process.
Refer to Fig. 5, the flow chart of its frequency calibrating method of concluding according to the present invention's conception.In order to conclude conception of the present invention, below the scanning frequency number represented with M in frequency scanning section, the number of N representative scanning group, P are represented the selecting frequency number altogether that each scanning group comprises.Wherein M=N+ (P-1), and P is more than or equal to 2.
In addition, in any two the adjacent frequency groups in N number of frequency group, identical (P-1) individual selecting frequency is comprised.With Fig. 2 example, each frequency group all comprises three selecting frequencies, and wherein first frequency group G1 and second frequency group G2 all comprises the second scanning frequency f2 in frequency scanning section and the 3rd scanning frequency f3.
First, frequency scanning section is divided into M scanning frequency (step S501), that is, according to frequency scanning class interval Δ f (as: 1.4ppm), frequency scanning section is divided into this M scanning frequency.And frequency scanning class interval Δ f defines according to the adjusting range of local side oscillator.
Because frequency scanning section is centered by initial oscillation, be chosen at the scanning frequency at initial oscillation two ends with the frequency scanning class interval Δ f of integral multiple, therefore, initial oscillation is the mean value of this frequency scanning section.Moreover M is odd number, and initial oscillation is (M+1)/2 scanning frequency.
According to M scanning frequency, frequency reducing is carried out to a Received signal strength, and draw M the Received signal strength (step S502) after frequency reducing.That is, according to predefined procedure one by one after M scanning frequency chooses one, using selected scanning frequency as the frequency with reference to oscillator signal; And after utilizing oscillating reference signal to carry out frequency reducing to received signal, draw M the Received signal strength after frequency reducing.Predefined procedure described herein can be increase progressively choose order, successively decrease choose order, random selecting order
Afterwards, then after respectively a correlation operation is carried out to the Received signal strength of this M after frequency reducing, draw M correlativity calculation result (step S503) accordingly.
Further analyzing step S503 can learn that its practice is: choose order according to one and select one first compensated scanning frequency from this M scanning frequency; The frequency reducing to received signal through this first compensated scanning frequency and oscillating reference signal; And one first correlation calculations is carried out to this Received signal strength after frequency reducing.It is noted that, the selection of predefined procedure can change, such as: increase progressively choose order, successively decrease choose order, random selecting order etc.
The representative of random selecting order is when carrying out correlation operation to scanning frequency, and (interleave) selects scanning frequency in an interleaved manner, and when adopting this kind of practice, the interference cases between signal can comparatively alleviate.
Subsidiary one carries, and can learn, can record Received signal strength, and accelerate the efficiency of frequency correction through storage element according to aforesaid the second execution mode.When adopting the second execution mode, step S503 can be further subdivided into following steps:
Initial oscillation is utilized to carry out frequency reducing to received signal and draw initial down-scaled signals; Store initial down-scaled signals; And utilize the frequency-splitting of the M between each scanning frequency and initial oscillation respectively and frequency reducing is carried out to initial down-scaled signals, and then draw M the Received signal strength after frequency reducing.
Then, distinguish N number of frequency group in M scanning frequency, wherein each frequency group all comprises an adjacent P selecting frequency (step S504).
Concerning M scanning frequency, other scanning frequency individual all may correspond to and draws correlativity calculation result, therefore total M correlativity calculation result.
Concerning N number of frequency group, multiple selecting frequencies (such as: nine) that each frequency group Gj comprises are all corresponding to scanning frequencys different in frequency scanning section.And these selecting frequencies can divide into center selecting frequency and subordinate selecting frequency.
Step S504 refers to first in units of frequency group, calculates the correlativity calculation result corresponding to each selecting frequency in each frequency pool.
Then, respectively group's computing carried out to N number of frequency group and draw N number of group operation result (step S505).
The thin portion flow process of probing into step S505 further comprises: in N number of frequency group, choose the frequency group carrying out computing; In M correlativity calculation result, P correlativity calculation result is selected according to selected frequency group; By P weight one by one corresponding to after P the correlativity calculation result selected, be weighted summation computing; And, repeat These steps and draw the N number of weighted sum operation result corresponding with N number of frequency group.
For example, for the selecting frequency belonging to same frequency group, the correlativity calculation result y of each selecting frequency in frequency group is distributed in jcorresponding weight, and carry out weighted sum computing.Certainly, before assigning weight, the selecting frequency F that frequency group comprises must be determined in advance jnumber.In addition, the correlativity calculation result y of each selecting frequency in frequency group jcorresponding weight w j, can determine according to a ratio function.
Afterwards, then in this N number of frequency group, select selected frequency group according to this N number of group operation result, and draw this correction frequency of oscillation (step S506) from this selected frequency group.
Step S506 refers to comparison according to this N number of group operation result and draws an extreme value (such as: the maximum in this N number of group operation result); Select there is the frequency group of this extreme value as this selected frequency group; And, in the scanning frequency corresponding to P the selecting frequency that this selected frequency group comprises, draw this correction frequency of oscillation.
Wherein, draw from selected frequency pool group P the selecting frequency that correction frequency of oscillation refers to comprise according to selected frequency group and draw center selecting frequency, and using the scanning frequency corresponding to the selecting frequency of center as correction frequency of oscillation.
When P is odd number, center selecting frequency refers to the scanning frequency corresponding to the selecting frequency of (P+1)/2 in selected frequency group; And when P is even number, center selecting frequency refers to the mean value of (P/2) individual selecting frequency in selected frequency group and [(P/2)+1] scanning frequency corresponding to individual selecting frequency.
According to conception of the present invention, in the process of carrying out frequency coarse adjustment, 256 chips in PSCH sequence can be used fully.Therefore, even if when channel condition is undesirable, the practice that the present invention conceives to adopt still can guarantee its stability.
In sum, the present invention proposes the conception of object when judging using frequency group as extreme value.This kind of practice avoids the phenomenon that single scanning frequency is easily subject to noise interference effect.In addition, analog result also demonstrates this kind of conception and can provide preferably detected ratios.
Moreover, also can find out according to aforesaid preferred embodiment, if when providing data storage element further, can first utilize the oscillating reference signal with initial oscillation to carry out frequency reducing to received signal.Then initial down-scaled signals is stored, making follow-up when utilizing test signal to carry out frequency reducing calculating, significantly can promote processing speed.
Subsidiary one carries, and corresponds to the weight of the P corresponding to correlativity calculation result of each scanning frequency, can also decide through a ratio function in frequency group.For example, ratio beta is represented with the ratio function of the 6th formula:
β=| ∫ ts (t-t b) × s *(t-t b) exp (j2 π (f i-f i+n) t) dt|/| ∫ ts (t-t b) × s *(t-t b) dt| (the 6th formula)
Refer to Fig. 6, it is in frequency group, changes the ratio function schematic diagram that weight allocation uses.It is noted that, conception of the present invention is, can determine ranking operation weight when weighted sum calculates according to ratio beta, but the ratio function of definition ratio beta is not limited with the 6th formula, and the 7th formula as below is also another citing.
β=| ∫ ts (t-t b) × s *(t-t b) exp (j2 π (f i-f i+n) t) dt| 2/ | ∫ ts (t-t b) × s *(t-t b) dt| 2(the 7th formula)
In addition, if when α (t) can draw according to modes such as assessment, calculating, predictions, then also can be arranged in pairs or groups in ratio function, the 8th such as following formula and the 9th formula.
β=| ∫ tα (t) s (t-t b) × s *(t-t b) exp (j2 π (f i-f i+n) t) dt|/| ∫ tα (t) s (t-t b) × s *(t-t b) dt| (the 8th formula)
β=| ∫ tα (t) s (t-t d) × s *(t-t d) exp (j2 π (f i-f i+n) t) dt| 2/ | ∫ tα (t) s (t-t d) × s *(t-t d) dt| 2(the 9th formula)
Except determining the ranking operation weight corresponding to each correlativity calculation result according to ratio function, ranking operation weight corresponding to each selecting frequency can also adjust according to the needs of system design, such as all using 1 as weight, or give a larger ranking operation weight etc. to the selecting frequency of particular order.
Definition according to 3GPP TS 34.12 specification can be learnt, when carrying out efficiency measuring in multipath fading environments (multi-pathfading environment), can test according to propagation conditions (propagation condition).Referring to this part of specification file the 493rd page form D.2.2.1, there is defined six kinds of representative situations.
Below utilize Fig. 7 A ~ 7C to represent first three kind situation in these six kinds of situations respectively, and with common technology and this case practice, efficiency measuring is carried out to it respectively.Because the test comparison result of other situations is all similar, the situation that row are all no longer in detail herein.In the drawings, delivering power Io is equivalent to the summation (Io=Ior+Ioc) of actual delivering power Ior and noise power Ioc.For different passage (channel), the ratio of the shared power of Ior representative, therefore the value of Ior can change along with the difference of passage.
In the drawings, all with the power (Ec/Io) that transverse axis representative transmits, and with longitudinal axis representative when carrying out fine tuning, error frequency f errorthe detected ratios of frequency level apart from Δ f (1.4ppm) can be less than.
Refer to Fig. 7 A, it is respectively by common technology and conception practice of the present invention efficiency ratio comparatively schematic diagram when the first situation that 3GPP TS 34.12 form is D.2.2.1 defined.
The first multichannel situation refers to the first frequency band (Band I), the second frequency band (Band II) is three kilometers (3km/h) per hour with the speed of the 3rd frequency band (Band III), and the 5th frequency band (Band V) is seven kilometers (7km/h) per hour with the speed of the 6th frequency band (VI).Wherein comprise the signal of two paths (Path), and the signal in these two paths has different average powers.The relative average power (Relative meanPower) in one of them path is 0 decibel (dB), and relative delay (Relative Delay) was 0 how second (nanosecond, referred to as ns); The relative average power in another path is-10dB, and relative delay is 976ns.
Fig. 7 A utilizes the result of calculation of maximum weighted summation according to the present invention's conception with solid line representative, and utilize the result utilizing maximum correlation to export with represented by dotted arrows common technology.When transverse axis position is identical, the longitudinal axis positions corresponding to each point on the solid line of the practice of the present invention is all comparatively high corresponding to the longitudinal axis positions of each point on the dotted line of the common technology practice.It can thus be appreciated that, when delivering power is identical, when adopting frequency pool prescription formula to carry out the estimation revising frequency of oscillation, there is preferably detected ratios.
Refer to Fig. 7 B, it is respectively by located by prior art and conception practice of the present invention efficiency ratio comparatively schematic diagram when the second multichannel situation that 3GPP TS 34.12 form is D.2.2.1 defined.
In the second multichannel situation, each frequency band (Band I ~ VI) is all identical with the first multichannel situation, and comprises the signal in three paths.These three paths have identical average power (being 0dB), and wherein the relative delay in the first path is 0ns, and the relative delay in the second path is 976ns: the relative delay in the third path is 20000ns.
Fig. 7 B utilizes the result of calculation of maximum weighted summation equally according to the present invention's conception with solid line representative, and utilize the result utilizing maximum correlation to export with represented by dotted arrows common technology.When delivering power is identical (when transverse axis position is identical), on solid line, the longitudinal axis positions of each point is all high compared with the longitudinal axis positions of each point on dotted line, and the detected ratios representing solid line is good compared with the detected ratios of dotted line.
Refer to Fig. 7 C, it is respectively by located by prior art and conception practice of the present invention efficiency ratio comparatively schematic diagram when the third situation that 3GPP TS 34.12 form is D.2.2.1 defined.
The third multichannel situation is equivalent to situation when user is in fast moving, therefore, first frequency band (Band I), the second frequency band (Band II) are 120km/h with the speed of the 3rd frequency band (Band III), and the 5th frequency band (Band V) is 282km/h with the speed of the 6th frequency band (VI).Wherein comprise the signal of four paths (Path).
The relative average power in first path is 0dB, and relative delay is 0ns; The relative average power in second path is-3dB, and relative delay is 260ns; The relative average power in the 3rd path is-6dB, and relative delay is 521ns; And the relative average power in the 4th path is-9dB, and relative delay is 781ns.
Fig. 7 C utilizes the result of calculation of maximum weighted summation according to the present invention's conception with solid line representative, and utilize the result utilizing maximum correlation to export with represented by dotted arrows common technology.When transverse axis position is identical, on solid line, the longitudinal axis positions of each point is all high compared with the longitudinal axis positions of each point on dotted line.It can thus be appreciated that when delivering power is identical, the detected ratios of solid line is all good compared with the detected ratios of dotted line.
In summary, when the appended drawings illustrating three kinds of multipath fading environments according to 3GPP TS 34.12 form is D.2.2.1 defined, detected ratios when transmitting with different delivering powers, and correspondence compares the difference of common technology and this case technology.
In the drawings and in which, point representative the closer to right side transmitted with higher delivering power, as can be seen from accompanying drawing also, all compared with the point (corresponding to lower delivering power) of opposing left, there is higher detected ratios the closer to the point (correspond to higher delivering power) on right side in accompanying drawing.That is the detected ratios when delivering power is-19dB is for the poorest; Detected ratios when delivering power is-17.5dB is taken second place; And the detected ratios when delivering power is-14.5dB is for best.
Also can be found out, adopt the comparison of maximum weighted summation operation result proposed by the invention can have better detected ratios than adopting the output of the maximum correlation of common technology to compare the practice by Fig. 7 A ~ 7C.That is, if premised on the condition transmission signal of equal-wattage time, the invention provides to estimate comparatively accurately and revise the practice of frequency of oscillation.
Finally, it is noted that, although aforesaid explanation is the example using the Pnmary Synchronization sequence of WCDMA system (primary synchronization sequence) as frequency correction, conception of the present invention is not limited with the application of WCDMA system.
When practical application, as long as Received signal strength s (t) is a sequence through design with automatic correlation (auto-correlation property).Therefore, even the communication system of other types also can adopt conception of the present invention.
For example, DVB-T system uses phase quadruple reversion modulation (Quadrature Phase ShiftKeying, quadriphase PSK, referred to as QPSK) carry out the transmission of signal, and after this kind of modulation mode need to carry out frequency correction equally, transmission DVB-T signal that could be correct.Or, for the mobile communication of other types, above-mentioned conception can be followed equally and carry out frequency correction.
In sum, although the present invention with preferred embodiment disclose as above, so itself and be not used to limit the present invention.Persond having ordinary knowledge in the technical field of the present invention, without departing from the spirit and scope of the present invention, when being used for a variety of modifications and variations.Therefore, protection scope of the present invention is as the criterion when defining with claims.

Claims (16)

1. a frequency calibrating method, is applied to an oscillating reference signal, and make the frequency of this oscillating reference signal be corrected to a correction frequency of oscillation by an initial oscillation, this frequency calibrating method comprises following steps:
One frequency scanning section is divided into M scanning frequency;
According to this M scanning frequency, frequency reducing is carried out to a Received signal strength, and draw M the Received signal strength after frequency reducing;
After respectively a correlation operation is carried out to the individual Received signal strength after frequency reducing of this M, draw M correlativity calculation result accordingly;
In this M scanning frequency, distinguish N number of frequency group, wherein respectively this frequency group all comprises P selecting frequency, and this P selecting frequency corresponds to P scanning frequency adjacent in this frequency scanning section;
Respectively group computing carried out to this N number of frequency group and draw N number of group operation result; And
In this N number of frequency group, select a selected frequency group according to this N number of group operation result, and draw this correction frequency of oscillation from this selected frequency group.
2. frequency calibrating method as claimed in claim 1, is characterized in that, in any two the adjacent frequency groups in this N number of frequency group, comprise identical (P-1) individual selecting frequency.
3. frequency calibrating method as claimed in claim 1, it is characterized in that, M is odd number, and this initial oscillation is (M+1)/2 scanning frequency.
4. frequency calibrating method as claimed in claim 1, it is characterized in that, this initial oscillation is the mean value of this frequency scanning section.
5. frequency calibrating method as claimed in claim 1, it is characterized in that, M=N+ (P-1), and P is more than or equal to 2.
6. frequency calibrating method as claimed in claim 1, is characterized in that, the step that this frequency scanning section divides into this M scanning frequency referred to: according to a frequency scanning class interval, this frequency scanning section is divided into this M scanning frequency.
7. frequency calibrating method as claimed in claim 1, is characterized in that, carry out frequency reducing according to this M scanning frequency and this initial oscillation to this Received signal strength, and show that the step of M the Received signal strength after frequency reducing refers to:
According to a predefined procedure one by one after this M scanning frequency chooses one, using selected scanning frequency as the frequency of this oscillating reference signal; And
After utilizing this oscillating reference signal to carry out frequency reducing to this Received signal strength, draw this M the Received signal strength after frequency reducing.
8. frequency calibrating method as claimed in claim 7, is characterized in that, this predefined procedure is one increase progressively and choose order, and successively decrease and choose order, a random selecting order.
9. frequency calibrating method as claimed in claim 1, is characterized in that, carry out this group's computing respectively and show that the step of N number of group operation result comprises following steps to this N number of frequency group:
The frequency group carrying out computing is chosen in this N number of frequency group;
In this M correlativity calculation result, P correlativity calculation result is selected according to selected frequency group;
By P weight one by one corresponding to after this P correlativity calculation result selected, carry out a weighted sum computing; And,
Repeat These steps and draw N number of weighted sum operation result that frequency group N number of with this is corresponding.
10. frequency calibrating method as claimed in claim 9, is characterized in that, P the selecting frequency that this P correlativity calculation result comprises according to selected frequency group and drawing.
11. frequency calibrating methods as claimed in claim 9, it is characterized in that, this P weight determines according to a ratio function.
12. frequency calibrating methods as claimed in claim 1, is characterized in that, select this selected frequency group, and show that the step of this correction frequency of oscillation comprises following steps from this selected frequency group according to this N number of group operation result in this N number of frequency group:
An extreme value is drawn according to the comparison of this N number of group operation result;
Select there is the frequency group of this extreme value as this selected frequency group; And,
In P the selecting frequency that this selected frequency group comprises, draw this correction frequency of oscillation.
13. frequency calibrating methods as claimed in claim 12, is characterized in that, this extreme value is the maximum comparing this N number of group operation result and draw.
14. frequency calibrating methods as claimed in claim 12, it is characterized in that, in P selecting frequency corresponding to this selected frequency group, show that the step of this correction frequency of oscillation refers to: draw a center selecting frequency according to this P selecting frequency, Bing Yigai center selecting frequency is as this correction frequency of oscillation.
15. frequency calibrating methods as claimed in claim 14, is characterized in that:
When P is odd number, this center selecting frequency refers to (P+1)/2 selecting frequency in this selected frequency group; And
When P is even number, this center selecting frequency refers to the average of (P/2) individual selecting frequency in this selected frequency group and [(P/2)+1] individual selecting frequency.
16. frequency calibrating methods as claimed in claim 1, is characterized in that, carry out frequency reducing according to this M scanning frequency and this initial oscillation to this Received signal strength, and show that the step of this M the Received signal strength after frequency reducing comprises following steps:
This initial oscillation is utilized to carry out frequency reducing to this Received signal strength and draw an initial down-scaled signals;
Store this initial down-scaled signals; And
Utilize the frequency-splitting of the M respectively between this scanning frequency and this initial oscillation respectively and frequency reducing is carried out to this initial down-scaled signals, and then drawing this M the Received signal strength after frequency reducing.
CN201210068638.XA 2012-03-15 2012-03-15 Frequency correcting method Expired - Fee Related CN103312372B (en)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1249580A (en) * 1998-09-30 2000-04-05 富士通株式会社 Method and apparatus for demodulating in radio communication system by M sequence orthogonal modulating
CN101989863A (en) * 2010-11-04 2011-03-23 华为终端有限公司 Rapid frequency deviation tracking device and method

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1249580A (en) * 1998-09-30 2000-04-05 富士通株式会社 Method and apparatus for demodulating in radio communication system by M sequence orthogonal modulating
CN101989863A (en) * 2010-11-04 2011-03-23 华为终端有限公司 Rapid frequency deviation tracking device and method

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