CN100502249C - Receiver and automatic frequency control method - Google Patents
Receiver and automatic frequency control method Download PDFInfo
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- CN100502249C CN100502249C CNB028119835A CN02811983A CN100502249C CN 100502249 C CN100502249 C CN 100502249C CN B028119835 A CNB028119835 A CN B028119835A CN 02811983 A CN02811983 A CN 02811983A CN 100502249 C CN100502249 C CN 100502249C
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/69—Spread spectrum techniques
- H04B1/707—Spread spectrum techniques using direct sequence modulation
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/69—Spread spectrum techniques
- H04B1/707—Spread spectrum techniques using direct sequence modulation
- H04B1/709—Correlator structure
Abstract
A searcher 105 creates a delay profile of a known symbol portion of a received base band signal by using a basic code, and a number-of-codes/kind-of-code determining unit 106 determines the number and kind of shift codes being used, on the basis of the delay profile. Correlators 108-1 to 108-n compute the correlation values between the known symbol first half of the received base band signal and the shift code. Correlators 109-1 to 109-n compute the correlation values between the known symbol second half of the received base band signal and the shift codes. A phase estimation unit 119 estimates the phase rotation per unit time by using the sum of the output signals of the correlators 108-1 to 108-n and the sum of the output signals of the correlators 109-1 to 109-n. As a result, the influence of the cross-correlation of spreading codes and the influence of noises are suppressed, so that the phase rotation between the known symbols can be estimated highly precisely to realize highly precise AFC.
Description
Technical field
The present invention relates to a kind of receiving system and auto frequency control method of the CDMA of being used for mode wireless communication system.
Background technology
In recent years, wireless communication system such as mobile phone and motor vehicle phone is popularized rapidly.In the communication terminal of wireless communication system, recipient's device carries out automatic frequency control (Automatic Frequency Control for the compensation and the deviation of the carrier frequency of sending method, device; Hereinafter referred to as " AFC ").
Below, with reference to Fig. 1, Fig. 2 explanation receiving system in the past.Fig. 1 is the figure of expression by the structure of time slot of the data that dispensing device sent.Fig. 2 is the block diagram of expression receiving system structure in the past.
As shown in Figure 1, the signal of dispensing device (not having diagram) transmission comprises known symbol 11 and the known symbol of crossing via CodeA and CodeB spread spectrum respectively 12.Wherein, the code length of CodeA and CodeB is respectively tCA and tCB, and the interval of known symbol 11 and known symbol 12 then is tgap.
The signal that sends via antenna 21 transmission and reception apparatus at as shown in Figure 2 receiving system.At Fig. 2, the signal (received signal) that receives via antenna 21 is receiving RF portion 22, and its frequency will be a base band by carrier frequency shift.At this moment, receiving the local signal that RF portion 22 uses oscillator 38 described later to be exported.In-phase component (I-ch) by the baseband signal (receiving baseband signal) that receives 22 outputs of RF portion is transformed to digital signal by A/D converter 23 and A/D converter 24 respectively with quadrature component (Q-ch), and output to searcher 25, correlator 26, correlator 27 and correlator 28.
Draw the relevant of the receiving baseband signal that is transformed to digital signal and known code CodeA at searcher 25, and detect the moment (time of reception of the CodeA) tA of correlation power when surpassing threshold value.In addition, calculate the tB time of reception of CodeB according to tA+tgap, and calculate the tData time of reception of data portion front at searcher 25 according to tA+tCA/2 at searcher 25.
The time of reception of 25 pairs of correlators 26 of searcher and synchronous detection portion 29 dateout portion fronts, to the time of reception of correlator 27 output CodeA, and to time of reception of correlator 28 output CodeB.
Correlator 26 is according to drawing the relevant of the data portion of receiving baseband signal and specified spreading code (being assigned to the spreading code of this receiving system) time of reception from the data portion front of searcher 25 inputs.The data portion of the receiving baseband signal after the relevant treatment then is output to synchronous detection portion 29.
Relevant according to from the known symbol that draws receiving baseband signal the time of reception 11 of the CodeA of searcher 25 inputs and CodeA of correlator 27.Similarly, relevant according to from the known symbol that draws receiving baseband signal the time of reception 12 of the CodeB of searcher 25 input and CodeB in correlator 28.
Synchronous detection portion 29 according to from time of reception of the data portion front of searcher 25 inputs the receiving baseband signal after to relevant treatment data portion carry out synchronous detection and handle.The data portion of the receiving baseband signal behind the synchronous detection is carried out demodulation at demodulation section 30, takes out to receive data.
The in-phase component of the known symbol 11 of the receiving baseband signal after the relevant treatment only postpones tAB (=tCA/2+tgap+tCB/2 in delay portion 31; With reference to Fig. 1) afterwards, export plural related operation portion 33 to.Similarly, the quadrature component of the known symbol 11 of the receiving baseband signal after the relevant treatment delay portion 32 only postpone tAB (=tCA/2+tgap+tCB/2) afterwards, export plural related operation portion 33 to.The in-phase component of the known symbol 12 of the receiving baseband signal after the relevant treatment and quadrature component then export plural related operation portion 33 respectively to.
Plural number related operation portion 33 uses the known symbol 11 of the receiving baseband signal after the relevant treatment and the in-phase component of known symbol 12 to carry out plural relevant treatment.In addition, the known symbol 11 of the receiving baseband signal after plural related operation portion 33 uses relevant treatment and the quadrature component of known symbol 12 are carried out plural relevant treatment.The in-phase component and the quadrature component of the receiving baseband signal after the plural number relevant treatment export phase estimation portion 34 to.
Phase estimation portion 34 uses the in-phase component of the receiving baseband signal after the plural relevant treatment of being exported from plural related operation portion 33 and the amount of phase rotation that quadrature component is estimated time per unit.The amount of phase rotation calculated rate side-play amount that estimates by phase estimation portion 34 in 35 bases of smoothing portion.Export the frequency offset that calculates to control voltage transformating part 36.
Control voltage transformating part 36 is transformed to the frequency offset that calculates the signal with the specified control voltage that puts on oscillator 38.Should after being transformed to analog signal, D/A converter 37 export oscillator 38 to from the signal of control voltage transformating part 36 outputs.Thus, the frequency of the local signal in the control generator 38 is with the compensating frequency side-play amount.
So, in the above-mentioned receiving system estimating received signal in the past known symbol to each other the amount of phase rotation and calculate frequency offset after, carry out AFC and come the compensating frequency side-play amount.
Yet, being subjected to by the influence of the phase cross-correlation of spreading code with by the influence of disturbing etc. because of obtaining known symbol after relevant, above-mentioned receiving system in the past is difficult to high accuracy and estimates the amount of phase rotation between known symbol, and exists the problem that the AFC precision worsens.
Summary of the invention
The object of the present invention is to provide a kind of receiving system and auto frequency control method, can suppress to realize high-precision AFC by the influence of the phase cross-correlation of spreading code with by the influence of disturbing and with the amount of phase rotation that high accuracy estimates between known symbol.
Transmit leg will be inserted by the known symbol that spreading code constituted that obtains by the sign indicating number displacement and send data and carry out multiplexing transmission, and recipient's use is estimated the amount of phase rotation with the numerical value of the correlation addition gained of a plurality of known symbols, can reach purpose of the present invention like this.
Receiving system of the present invention comprises: searching part, calculate first correlation, that is and, insert by the received signal of the known symbol that a part constituted of specifying basic code and the correlation of described basic code; Decision means, the quantity and the time under the time of reception thereof that surpass assign thresholds according to described first correlation are with, and judge the quantity and the kind of the known symbol that the elapsed time is multiplexing; The correlation value calculation parts, calculate second correlation, promptly, insert the received signal part and the correlation that is judged as multiplexing known symbol of elapsed time in described decision means of described known symbol first half, and calculating third phase pass value, that is the correlation of the latter half of and described known symbol of described known symbol, through judging; The amount of phase rotation estimation section is estimated the amount of phase rotation according to the phase difference of the addition result of the addition result of described second correlation and described third phase pass value; And frequency control part, according to the frequency of described the amount of phase rotation control generator with the compensating frequency side-play amount.
The invention provides a kind of communication terminal that is provided with receiving system, described receiving system comprises: searching part, calculate first correlation, that is and, insert by the received signal of the known symbol that a part constituted of specifying basic code and the correlation of described basic code; Decision means, the quantity and the time under the time of reception thereof that surpass assign thresholds according to described first correlation are with, and judge the quantity and the kind of the known symbol that the elapsed time is multiplexing; The correlation value calculation parts, calculate second correlation, promptly, insert the received signal part and the correlation that is judged as multiplexing known symbol of elapsed time in described decision means of described known symbol first half, and calculating third phase pass value, that is the correlation of the latter half of and described known symbol of described known symbol, through judging; The amount of phase rotation estimation section is estimated the amount of phase rotation according to the phase difference of the addition result of the addition result of described second correlation and described third phase pass value; And frequency control part, according to the frequency of described the amount of phase rotation control generator with the compensating frequency side-play amount.
The invention provides a kind of base station apparatus that is provided with receiving system, described receiving system comprises: searching part, calculate first correlation, that is and, insert by the received signal of the known symbol that a part constituted of specifying basic code and the correlation of described basic code; Decision means, the quantity and the time under the time of reception thereof that surpass assign thresholds according to described first correlation are with, and judge the quantity and the kind of the known symbol that the elapsed time is multiplexing; The correlation value calculation parts, calculate second correlation, promptly, insert the received signal part and the correlation that is judged as multiplexing known symbol of elapsed time in described decision means of described known symbol first half, and calculating third phase pass value, that is the correlation of the latter half of and described known symbol of described known symbol, through judging; The amount of phase rotation estimation section is estimated the amount of phase rotation according to the phase difference of the addition result of the addition result of described second correlation and described third phase pass value; And frequency control part, according to the frequency of described the amount of phase rotation control generator with the compensating frequency side-play amount.
Auto frequency control method of the present invention comprises the steps: to calculate first correlation, that is, insert by the received signal of the known symbol that a part constituted of specifying basic code and the correlation of described basic code; The quantity and the time under the time of reception thereof that surpass assign thresholds according to described first correlation are with, and judge quantity and kind through time-multiplexed known symbol; Calculate second correlation, that is, insert the received signal part and the correlation that is judged as through time-multiplexed known symbol of known symbol first half, and, calculate third phase pass value, that is, and the correlation of the latter half of and described known symbol of described known symbol through judging; Phase difference according to the addition result of the addition result of described second correlation and described third phase pass value is estimated the amount of phase rotation; And according to the frequency of described the amount of phase rotation control generator with the compensating frequency side-play amount.
Auto frequency control method of the present invention comprises the steps: to calculate first correlation, that is, insert by the received signal of the known symbol that a part constituted of specifying basic code and the correlation of described basic code; The quantity and the time under the time of reception thereof that surpass assign thresholds according to described first correlation are with, and judge the moment of quantity, kind and the relevant treatment of the known symbol that the elapsed time is multiplexing; Calculate correlation according to the moment of quantity, kind and the relevant treatment of the known symbol of described judgement through time-multiplexed one or more received signals; Use the additive value of described correlation to estimate the amount of phase rotation; And according to the frequency of described the amount of phase rotation control generator with the compensating frequency side-play amount.
Description of drawings
Fig. 1 is the figure of expression by the structure of time slot of the data of dispensing device transmission;
Fig. 2 is the block diagram of expression receiving system structure in the past;
Fig. 3 is used for the figure of generation method of the spreading code of known symbol of the present invention portion for explanation;
Fig. 4 carries out the structure of time slot figure of the data that base station apparatus sent of radio communication for the communication terminal of the relevant embodiment of the invention 1;
Fig. 5 is the block diagram of the communication terminal structure of the relevant the foregoing description of expression;
Fig. 6 is the figure that is illustrated in the delay distribution of being made in the communication terminal of relevant the foregoing description;
Fig. 7 A is the figure that is illustrated in the amount of phase rotation estimated in the communication terminal of relevant the foregoing description;
Fig. 7 B is the figure that is illustrated in the amount of phase rotation estimated in the communication terminal of relevant the foregoing description;
Fig. 7 C is the figure that is illustrated in the amount of phase rotation estimated in the communication terminal of relevant the foregoing description; And,
Fig. 8 is the block diagram of the communication terminal structure of the relevant embodiment of the invention 2 of expression.
Embodiment
Before beginning that each embodiment is described, at first be example with Fig. 3, the generation method of transmit leg among the present invention being inserted the spreading code of the known symbol that sends data describes.
In Fig. 3, be P (chip) with the length of basic code, it is W (chip) that the maximum of radiolink is delayed distribution length.And with two identical basic code series connection, the place ahead is basic code BC1, and the rear is basic code BC2.
Made by on basic code BC1, adding W part institute corresponding to user 1 spread spectrum codes C ode1 from the front of basic code BC2.And begin to add that by the front of basic code BC1 being removed the front of W part back the part of 2 * W is made from basic code BC2 corresponding to user 2 spread spectrum codes C ode2.That is spread spectrum codes C ode2 is that only rearward mobile (Shift) W of part that will be equivalent to basic code Code1 in basic code BC1, BC2 draws afterwards.
If similarly number of users is K, corresponding to user i (i=1,2 ..., K) spread spectrum codes C odei be by after the part of removing (i-1) * W from the front of basic code BC1 again the front from basic code BC2 add that the part of i * W is made.The length of each spread spectrum codes C odei is Lm=P+W (chip).
Describe embodiments of the invention in detail hereinafter with reference to accompanying drawing.In addition, in the following description, transmit leg is a base station apparatus, and the recipient is a communication terminal.And, do not consider to postpone ripple in following explanation, and will be called [shift code] with the spreading code that method shown in Figure 3 generates.
Fig. 4 carries out the structure of time slot figure of the data that base station apparatus sent of radio communication for the relevant embodiment of the invention 1 with communication terminal.As shown in Figure 4, known symbol is inserted the slightly part of central authorities of time slot.This known symbol spreading code that method as shown in Figure 3 generates of promptly serving as reasons.Also have, multiply by the distinctive spreading code of each user in data portion.
The signal that base station apparatus will have as the structure of time slot of Fig. 4 carries out multiplexing to each communication terminal (user) in the communication and transmission.And, by the transmission reception of control signal basic code and shift amount are prenoticed to each communication terminal.
Fig. 5 is the block diagram of the communication terminal structure of the relevant present embodiment of expression.And Fig. 5 represents the structure of recipient in the communication terminal, and the structure of transmit leg is omitted.
103 pairs of in-phase components (I-ch) from the baseband signal (hereinafter referred to as " receiving baseband signal ") of reception RF portion 102 outputs of A/D converter are carried out the A/D conversion.Similarly, the quadrature component (Q-ch) of 104 pairs of receiving baseband signals of A/D converter is carried out the A/D conversion.
The delay that searcher 105 uses above-mentioned basic code shown in Figure 3 to make known symbol in the receiving baseband signal that is transformed to digital signal distributes, the moment when detecting its correlation power above threshold value (, and export yardage-kind judging part 106 to the time of reception of known symbol).In addition, searcher 105 according to known symbol the time of reception calculated data portion front the time of reception, and export correlator 107 and synchronous detection portion 110 to.
The time of reception of the known symbol that yardage-kind judging part 106 is sent according to searcher 105, quantity and kind thereof to the shift code in the present use are made judgement, and correlator 108-1 to n and correlator 109-1 to n (n is the natural number more than 2) are assigned relevant treatment instruction constantly.As for the details of the judgement of yardage-106 pairs of yardages of kind judging part and kind thereof with aftermentioned.
Correlator 107 is according to drawing time of reception of the data portion front of searcher 105 output relevant between the data portion of receiving baseband signal and the spreading code of appointment (being dispensed to the spreading code that self installs), exports the data portion of the receiving baseband signal after the relevant treatment to synchronous detection portion 110.
Correlator 108-1 to n goes out the known symbol first half of receiving baseband signal and the correlation of shift code (hereinafter referred to as " symbol first half correlation ") according to the command calculations of yardage-kind judging part 106 respectively.Similarly, correlator 109-1 to n goes out the correlation (hereinafter referred to as " the latter half of correlation of symbol ") of the latter half of and shift code of the known symbol of receiving baseband signal respectively according to the command calculations of yardage-kind judging part 106.
The in-phase component addition of the symbol first half correlation that adder 112 will be respectively calculated at correlator 108-1 to n.Similarly, the quadrature component addition of the adder 113 symbol first half correlation of will be respectively calculating at correlator 108-1 to n.
The in-phase component addition of the latter half of correlation of symbol that adder 114 will be respectively calculated at correlator 109-1 to n.Similarly, the quadrature component addition of the adder 115 latter half of correlation of symbol of will be respectively calculating at correlator 109-1 to n.
After delay portion 116 will postpone according to specified amount in the in-phase component of the symbol first half correlation of adder 112 additions, export plural related operation portion 118 to.Similarly, after delay portion 117 will postpone according to specified amount in the quadrature component of the symbol first half correlation of adder 113 additions, export plural related operation portion 118 to.
Plural number related operation portion 118 uses the in-phase component of the symbol first half correlation after the addition and the in-phase component of the latter half of correlation of symbol after the addition to carry out plural relevant treatment.Also have, plural related operation portion 118 uses the quadrature component of the symbol first half correlation after the additions and the quadrature component of the latter half of correlation of symbol after the addition to carry out plural relevant treatment.
The in-phase component of the correlation after the plural relevant treatment of the plural related operation of 119 uses portion of phase estimation portion 118 outputs and the amount of phase rotation that quadrature component is estimated time per unit.As for the details of the estimation of 119 pairs of the amount of phase rotation of phase estimation portion with aftermentioned.
The amount of phase rotation smoothing that smoothing portion 120 is estimated with phase estimation portion 119 is also calculated frequency offset.Control voltage transformating part 121 is transformed to the frequency offset that calculates to have the signal that puts on oscillator 123 specified control voltages and exports it to D/A converter 122.The signal transformation that D/A converter 122 will be controlled voltage transformating part 121 outputs is analog signal.The corresponding local signal of voltage of signals of oscillator 123 its frequencies of output and 122 outputs of D/A converter.
Next the implementation process of AFC in communication terminal shown in Figure 3 is described.
The wireless signal that sends from the base station is received antenna 101 and receives, and is transformed to base band frequency behind the local signal that reception RF portion 102 multiply by by oscillator 123 outputs.
The in-phase component of receiving baseband signal is transformed to digital signal at A/D converter 103, and the quadrature component of receiving baseband signal is transformed to digital signal at A/D converter 104.The receiving baseband signal that is transformed to digital signal is outputed to searcher 105, correlator 107, correlator 108-1 to n and correlator 109-1 to n.
Correlator 107 is according to drawing time of reception of data portion front relevant between the data portion of receiving baseband signal and the spreading code of the appointment spreading code of device (be dispensed to self), and synchronous detection portion 110 according to time of reception of data portion front the receiving baseband signal after to relevant treatment data portion carry out the processing of synchronous detection, the data portion of the receiving baseband signal behind 111 pairs of synchronous detections of demodulation section is carried out demodulation process, takes out to receive data.
Also have, correlator 108-1 to n is respectively according to the known symbol first half and the shift code compute sign first half correlation of receiving baseband signal.Similarly, correlator 109-1 to n is respectively according to the latter half of and latter half of correlation of shift code compute sign of the known symbol of receiving baseband signal.
The in-phase component and the quadrature component addition of the symbol first half correlation that adder 112,113 will be calculated respectively at correlator 108-1 to n.116,117 in delay portion postpones it according to specified amount.The in-phase component and the quadrature component addition of the latter half of correlation of symbol that adder 114,115 will be calculated respectively at correlator 109-1 to n.
Plural number related operation portion 118 is according to the in-phase component of the symbol first half correlation after the addition and the in-phase component of the latter half of correlation of symbol after the addition, and the quadrature component of the symbol first half correlation after the addition and the quadrature component of the latter half of correlation of symbol after the addition are carried out plural relevant treatment.
The in-phase component of the correlation of phase estimation portion 119 after according to plural relevant treatment and quadrature component are estimated the amount of phase rotation of time per unit.Smoothing portion 120 is with the amount of phase rotation smoothing and calculate frequency offset, and the frequency offset that calculates then exports control voltage transformating part 121 to.
Control voltage transformating part 121 is transformed to the signal with specified control voltage with the frequency offset that calculates, and this signal exports oscillator 123 to after D/A converter 122 is transformed to analog signal.The corresponding local signal of voltage of signals of oscillator 123 its frequencies of output and 122 outputs of D/A converter.
Next with representing that the Fig. 6 that postpones to distribute describes the judgment mode of yardage-106 pairs of yardages of kind judging part and kind thereof in detail.Fig. 6 is illustrated in the figure that relevant delay of being made distributes in the communication terminal of present embodiment.At Fig. 6, transverse axis is represented the time, and the longitudinal axis is represented power.
When base station apparatus carries out multiplexing transmission to a plurality of communication terminals with above-mentioned data shown in Figure 4, in case the delay that the recipient of communication terminal uses basic code to make known symbol in the receiving baseband signal distributes, can detect the peak value above threshold value, the quantity of this peak value is equal to the communication terminal that communicates at present.
When if base station apparatus uses shift code Codei and communication terminal to carry out radio communication, the moment that sends data with base station apparatus is 0, will displays from the moment (i-1) * W to the peak value of crossing threshold value less than the time band Ti wide-ultra of moment i * W.
For example, Fig. 6 demonstrates peak value P1 and the P3 that T1 and T3 wide-ultra are crossed threshold value, hence one can see that, and base station apparatus is to use shift code Code1 and shift code Code3 and communication terminal to carry out radio communication.
Yardage-kind judging part 106 judges that according to the number of peaks that surpasses threshold value present and base station apparatus carries out the quantity of the communication terminal of radio communication, and judges that according to the band of the time under this peak value base station apparatus is used for sending the shift code of signal known symbol.
At Fig. 6, yardage-106 couples of correlator 108-1 of kind judging part assign with moment P1 as relevant treatment instruction constantly, and correlator 108-2 is assigned with moment P3 as relevant treatment instruction constantly.In addition, yardage-kind judging part 106 is tk with the length of known symbol portion, correlator 109-1 is assigned with constantly (P1+tk/2) as relevant treatment instruction constantly, and correlator 109-2 is assigned with (P3+tk/2) constantly as relevant treatment instruction constantly.
Next, with Fig. 7 A that represents the amount of phase rotation, Fig. 7 B, Fig. 7 C describe the estimation mode of 119 pairs of the amount of phase rotation of phase estimation portion in detail.Fig. 7 A, Fig. 7 B, Fig. 7 C are the figure that is illustrated in the amount of phase rotation estimated in the communication terminal of relevant present embodiment.At Fig. 7 A, Fig. 7 B among Fig. 7 C, illustrates correlation with vector table on the IQ plane.
At Fig. 7 A, vector 201 is the known symbol first half of receiving baseband signal and the symbol first half correlation of shift code Code1, vector 202 is the known symbol first half of receiving baseband signal and the symbol first half correlation of shift code Code3, and vector 203 is the resultant vectors by vector 201 and vector 202 additions.
At Fig. 7 B, vector 211 is the latter half of and latter half of correlations of symbol shift code Code1 of the known symbol of receiving baseband signal, vector 212 is the latter half of and latter half of correlations of symbol shift code Code3 of the known symbol of receiving baseband signal, and vector 213 is the resultant vectors by vector 211 and vector 212 additions.
At Fig. 7 C, the differential seat angle θ of resultant vector 203 and resultant vector 213 represents the amount of phase rotation.Phase estimation portion 119 uses the numerical value after the addition of a plurality of known symbol correlation is estimated the amount of phase rotation.
Like this, transmit leg will be inserted by the known symbol that spreading code constituted that obtains by the sign indicating number displacement and send data and carry out multiplexing transmission, and thus, the recipient can calculate the correlation of a plurality of known signals.
At this, cause is stochastic regime to the phase cross-correlation and the interference of the spreading code that the known signal of obtaining after being correlated with influences to some extent, by correlation addition, can when estimating the amount of phase rotation, suppress by the influence of the phase cross-correlation of spreading code with by the influence of disturbing with a plurality of known symbols.
Therefore, to insert the transmission data and carry out multiplexing transmission by the known symbol that spreading code constituted that obtains by the sign indicating number displacement by transmit leg, and the recipient estimates the amount of phase rotation with the numerical value of the correlation addition gained of a plurality of known signals, can high accuracy estimate the amount of phase rotation between known symbol, and realize high-precision AFC.
Though comparatively desirable when being equal to the yardage that can communicate simultaneously as for the quantity n of correlator 108-1 to n and correlator 109-1 to n, the present invention is less than in the quantity of each correlator under the situation of yardage and also sets up.At this moment, select in regular turn from peak value the higher person in the shift code of yardage-kind judging part 106 in using at present, to the moment of correlator 108-1 to n and correlator 109-1 to n indication relevant treatment.
In the foregoing description 1, at present and the communication terminal that communicates of base station apparatus have only under one the situation, not only can't bring into play technical characterictic with the addition of known signal correlation, and, with time close known symbol first half and latter half of estimation the amount of phase rotation, the estimated accuracy of the amount of phase rotation is worsened more than prior art.
For addressing the above problem, in embodiment 2, the situation that the correlation that is used to estimate the amount of phase rotation switches is described according to the quantity of the shift code in using at present.
Fig. 8 is the block diagram of the communication terminal structure of the relevant embodiment of the invention 2 of expression.And, in the represented communication terminal that goes out of Fig. 8, for communication terminal shown in Figure 5 under the identical part of structure will give same mark and omit its explanation.
In communication terminal shown in Figure 8, the function of yardage-kind judging part 301 and the function of the yardage in the communication terminal shown in Figure 5-kind judging part 106 are different.In addition, compare with communication terminal shown in Figure 5, appended correlator 302,303 and switching part 304 on the structure at communication terminal shown in Figure 8.
Yardage-kind judging part 301 is judged the quantity and the kind thereof of the shift code in using at present according to the time of reception of the known symbol of searcher 105 outputs.Then, when the quantity of the shift code in using at present is a plurality of, the moment of yardage-301 couples of correlator 108-1 to n of kind judging part and correlator 109-1 to n (n is the natural number more than 2) indication relevant treatment.If one, then correlator 302 is indicated the moment of relevant treatment, and correlator 303 is assigned the instruction of implementation relevant treatment.
Have, yardage-kind judging part 301 carries out the switching controls of switch to switching part 304 according to the quantity of the shift code in the present use again.Be exactly specifically, when the quantity of the shift code in the present use when being a plurality of, carry out switching controls and make adder 112 and delayer 116, adder 113 and plural related operation portion 118, adder 114 and delayer 117 and adder 115 be connected respectively with plural related operation portion 118.On the contrary, when the quantity of the shift code in the present use is one, carries out switching controls and make correlator 302 and delayer 116, correlator 302 and plural related operation portion 118, correlator 303 and delayer 117 and correlator 303 be connected respectively with plural related operation portion 118.
The switching that switching part 304 connects according to the control of above-mentioned yardage-kind judging part 301.
Its result, when the quantity of the shift code in the present use was one, phase estimation portion 119 was according to all correlations of symbol and estimate the amount of phase rotation with the differential seat angle of control channel correlation synchronously.
So, by switching the correlation that is used to estimate the amount of phase rotation according to the quantity of shift code in using now, in the quantity of shift code when being a plurality of, can obtain the effect same, if the quantity of shift code also can be carried out stable AFC when being one with the foregoing description 1.
At this, use common synchronous situation in whole unit with control channel, might misapply the control channel of other unit and estimate the amount of phase rotation, at this moment, the introducing precision of frequency offset can worsen significantly.At this moment, each unit is distinctive estimates the amount of phase rotation with control channel synchronously by using, and can improve the stability of system.
Have again since to the synchronous side-play amount with control channel of time slot front because of the difference of unit difference to some extent, make synchronously with the position of the position of control channel and known symbol portion close in time sometimes.At this moment, can be as described in the embodiment 1, can high accuracy carry out AFC with first half and latter half of estimation the amount of phase rotation of known symbol portion.So, before setting up, learns in circuit synchronous position by communication terminal with control channel, and suitably switch the signal that is used to estimate the amount of phase rotation according to control channel and known symbol portion position relation each other, can realize often keeping stable AFC to a certain degree.
In addition, can be with above-mentioned each embodiment and space diversity reception, path diversity receives combination mutually to realize more stable and high-precision AFC.
Having, in the various embodiments described above, is base station apparatus to transmit leg again, and the recipient is illustrated for the situation of communication terminal, but the present invention also is applicable to that working as the recipient is base station apparatus, and transmit leg is under the situation of communication terminal.
And, in the various embodiments described above, do not consider to postpone ripple, but the present invention also can obtain above-mentioned effect if equipment is implemented channel estimating and the synthetic structure division that waits of RAKE in receiving system in the communication environments that postpones the ripple existence for simplified illustration.
Moreover, in above-mentioned each embodiment, by with the known symbol correlation addition of other time slots and carry out estimating the amount of phase rotation behind the plural related operation, can suppress further by the influence of the phase cross-correlation of spreading code with by the influence of disturbing, and realize more high-precision AFC.
In sum, by the present invention, because can be, can suppress by the influence of the phase cross-correlation of spreading code with by the influence of disturbing and estimate the amount of phase rotation between the known symbol accurately, and then realize high-precision AFC the addition of a plurality of known symbol correlation.
This specification is based on the 2000-278193 Japan Patent of application on September 13rd, 2000, and its full content is contained in this.
Utilizability on the industry
The present invention is applicable to communication terminal or the base station in the wireless communication system of CDMA mode.
Claims (8)
1, a kind of receiving system comprises: searching part, calculate first correlation, that is and, insert by the received signal of the known symbol that a part constituted of specifying basic code and the correlation of described basic code;
Decision means, the quantity and the time under the time of reception thereof that surpass assign thresholds according to described first correlation are with, and judge the quantity and the kind of the known symbol that the elapsed time is multiplexing;
The correlation value calculation parts, calculate second correlation, promptly, insert the received signal part and the correlation that is judged as multiplexing known symbol of elapsed time in described decision means of described known symbol first half, and calculating third phase pass value, that is the correlation of the latter half of and described known symbol of described known symbol, through judging;
The amount of phase rotation estimation section is estimated the amount of phase rotation according to the phase difference of the addition result of the addition result of described second correlation and described third phase pass value; And
Frequency control part, according to the frequency of described the amount of phase rotation control generator with the compensating frequency side-play amount.
2, receiving system as claimed in claim 1, wherein: the correlation value calculation parts, calculate the 4th correlation, promptly, insert the received signal part and the correlation that is judged as in decision means through time-multiplexed known symbol of known symbol, and, the 5th correlation calculated, that is the correlation of the spreading code of received signal and control channel; The amount of phase rotation estimation section then when when the quantity of time-multiplexed known symbol is one, is estimated the amount of phase rotation according to the phase difference of described the 4th correlation and described the 5th correlation.
3, receiving system as claimed in claim 2, wherein, the correlation value calculation parts use the distinctive control channel in unit to calculate the 5th correlation.
4, receiving system as claimed in claim 2, wherein, even the amount of phase rotation estimation section is when the quantity through time-multiplexed known symbol is one, when control channel is close in time with known symbol, then estimate the amount of phase rotation according to the phase difference of described second correlation and described third phase pass value.
5, a kind of communication terminal that is provided with receiving system, described receiving system comprises: searching part, calculate first correlation, that is, insert by the received signal of the known symbol that a part constituted of specifying basic code and the correlation of described basic code;
Decision means, the quantity and the time under the time of reception thereof that surpass assign thresholds according to described first correlation are with, and judge the quantity and the kind of the known symbol that the elapsed time is multiplexing;
The correlation value calculation parts, calculate second correlation, promptly, insert the received signal part and the correlation that is judged as multiplexing known symbol of elapsed time in described decision means of described known symbol first half, and calculating third phase pass value, that is the correlation of the latter half of and described known symbol of described known symbol, through judging;
The amount of phase rotation estimation section is estimated the amount of phase rotation according to the phase difference of the addition result of the addition result of described second correlation and described third phase pass value; And
Frequency control part, according to the frequency of described the amount of phase rotation control generator with the compensating frequency side-play amount.
6, a kind of base station apparatus that is provided with receiving system, described receiving system comprises: searching part, calculate first correlation, that is, insert by the received signal of the known symbol that a part constituted of specifying basic code and the correlation of described basic code;
Decision means, the quantity and the time under the time of reception thereof that surpass assign thresholds according to described first correlation are with, and judge the quantity and the kind of the known symbol that the elapsed time is multiplexing;
The correlation value calculation parts, calculate second correlation, promptly, insert the received signal part and the correlation that is judged as multiplexing known symbol of elapsed time in described decision means of described known symbol first half, and calculating third phase pass value, that is the correlation of the latter half of and described known symbol of described known symbol, through judging;
The amount of phase rotation estimation section is estimated the amount of phase rotation according to the phase difference of the addition result of the addition result of described second correlation and described third phase pass value; And
Frequency control part, according to the frequency of described the amount of phase rotation control generator with the compensating frequency side-play amount.
7, a kind of auto frequency control method comprises the steps: to calculate first correlation, that is, insert by the received signal of the known symbol that a part constituted of specifying basic code and the correlation of described basic code; The quantity and the time under the time of reception thereof that surpass assign thresholds according to described first correlation are with, and judge quantity and kind through time-multiplexed known symbol; Calculate second correlation, that is, insert the received signal part and the correlation that is judged as through time-multiplexed known symbol of known symbol first half, and, calculate third phase pass value, that is, and the correlation of the latter half of and described known symbol of described known symbol through judging; Phase difference according to the addition result of the addition result of described second correlation and described third phase pass value is estimated the amount of phase rotation; And according to the frequency of described the amount of phase rotation control generator with the compensating frequency side-play amount.
8. an auto frequency control method comprises the steps:
Calculate first correlation, that is, insert by the received signal of the known symbol that a part constituted of specifying basic code and the correlation of described basic code;
The quantity and the time under the time of reception thereof that surpass assign thresholds according to described first correlation are with, and judge the moment of quantity, kind and the relevant treatment of the known symbol that the elapsed time is multiplexing;
Calculate correlation according to the moment of quantity, kind and the relevant treatment of the known symbol of described judgement through time-multiplexed one or more received signals;
Use the additive value of described correlation to estimate the amount of phase rotation; And
According to the frequency of described the amount of phase rotation control generator with the compensating frequency side-play amount.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| PCT/JP2002/002227 WO2003077438A1 (en) | 2002-03-11 | 2002-03-11 | Receiver and automatic frequency control method |
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| CN1516929A CN1516929A (en) | 2004-07-28 |
| CN100502249C true CN100502249C (en) | 2009-06-17 |
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| CNB028119835A Expired - Fee Related CN100502249C (en) | 2002-03-11 | 2002-03-11 | Receiver and automatic frequency control method |
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| CN (1) | CN100502249C (en) |
| AU (1) | AU2002236278A1 (en) |
| WO (1) | WO2003077438A1 (en) |
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| JP4809097B2 (en) * | 2006-03-29 | 2011-11-02 | ルネサスエレクトロニクス株式会社 | Reception circuit and reception method |
| CN101335599B (en) * | 2007-06-25 | 2013-03-13 | 上海贝尔阿尔卡特股份有限公司 | Space relativity resisting method and apparatus for spatial multiplexing system of wireless network |
| US9584355B2 (en) * | 2013-03-25 | 2017-02-28 | Intel Deutschland Gmbh | Device and method for frequency offset estimation |
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| JP2672769B2 (en) * | 1992-06-29 | 1997-11-05 | 三菱電機株式会社 | Spread spectrum receiver |
| JP3419361B2 (en) * | 1999-09-29 | 2003-06-23 | 株式会社デンソー | Spread spectrum receiver |
| JP3588043B2 (en) * | 2000-09-13 | 2004-11-10 | 松下電器産業株式会社 | Receiver and automatic frequency control method |
-
2002
- 2002-03-11 CN CNB028119835A patent/CN100502249C/en not_active Expired - Fee Related
- 2002-03-11 WO PCT/JP2002/002227 patent/WO2003077438A1/en active Application Filing
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| WO2003077438A1 (en) | 2003-09-18 |
| AU2002236278A1 (en) | 2003-09-22 |
| CN1516929A (en) | 2004-07-28 |
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