CN1933471B - OFDM reception method and apparatus - Google Patents

OFDM reception method and apparatus Download PDF

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Publication number
CN1933471B
CN1933471B CN2006101515142A CN200610151514A CN1933471B CN 1933471 B CN1933471 B CN 1933471B CN 2006101515142 A CN2006101515142 A CN 2006101515142A CN 200610151514 A CN200610151514 A CN 200610151514A CN 1933471 B CN1933471 B CN 1933471B
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interpolation
time
extrapolation
transmission line
symbol
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CN1933471A (en
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仲田树广
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Hitachi Kokusai Electric Inc
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Hitachi Kokusai Electric Inc
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/26—Systems using multi-frequency codes
    • H04L27/2601—Multicarrier modulation systems
    • H04L27/2647—Arrangements specific to the receiver only
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L25/00—Baseband systems
    • H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
    • H04L25/20—Repeater circuits; Relay circuits
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/01—Equalisers

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Power Engineering (AREA)
  • Radio Relay Systems (AREA)

Abstract

To shorten delay times of several symbols of a time interpolation system for interpolating transmission path characteristics by interpolating from reception SPs before and after the symbol interpolated in interpolating the transmission path characteristics of the symbol having not arranged with SPs from a reception SP signal distributed and arranged in a time direction. In interpolating the transmission path from the reception SP, a plurality of reception SPs received in the past are multiplied by different predetermined coefficients, their results are complex-added, and transmission path characteristics of the symbol having no arranged carrier pilot are interpolated by time direction extrapolation processing such as the compositing of primary extrapolation or the reception SPs at a predetermined coefficient rate.

Description

OFDM method of reseptance and device thereof
Technical field
The present invention relates to receive the received terrestrial digital broadcasting that utilizes OFDM mode (Orthogonal FrequencyDivision Multiplexing abbreviates OFDM below as) modulation, carry out the technology of the relay of broadcast wave relaying.
Background technology
In recent years, in the wireless device field, as anti-multichannel fade performance and the strong modulation system of moving body conveying function, the OFDM mode is gazed at, and is carrying out multiple application study with the various countries headed by Europe and the Japan.
In Japan, begun to adopt the received terrestrial digital broadcasting of the UHF frequency band of OFDM mode in December, 2003, for this exploitation trend and mode, write up is at map information medium association magazine (reflection feelings Reported メ デ イア Hui Chi) 1998 Vol.52, No.11 (with reference to non-patent literature 1).
So, in order generally to broadcast this received terrestrial digital broadcasting, used to receive from the former broadcasting of the UHF frequency band of total platform and use the frequency different or identical frequency sends the broadcast wave relay of received terrestrial digital broadcasting once more with receiving channels in the Japanese whole nation.
The former repeater of broadcasting once more with different frequency mainly uses in MFN (multifrequency relaying, Multi Frequency Network) environment.The latter's the repeater of broadcasting once more with same frequency is mainly at SFN (single-frequency relaying: Single Frequency Network) use in the environment, improved the utilization ratio of frequency.
Below, the summary of MFN repeater and SFN repeater is described.
At first, represent the structure of the MFN of prior art, the feature of MFN repeater is described with Fig. 2 with repeater at Fig. 2.
After the signal that is received by reception antenna 21 is sampled by A/D22, be the frequency axis signal in FFT portion 23 from the time shaft conversion of signals, output frequency axis signal r (t, and k) (wherein, t is-symbol numbering, k is a carrier index).In transmission line property interpolation portion 25 according to the pilot signal that is included in the received signal, the transmission line property of interpolation from total platform to reception antenna.
For the interpolation algorithm of this transmission line property, utilize Fig. 3 and Fig. 4 to describe.Fig. 3 is the key diagram of the pilot signal that adopts in the received terrestrial digital broadcasting mode.The carrier wave of representing with black circle among the figure is the known pilot frequency carrier wave of amplitude, phase place, is disposing dispersedly in frequency (carrier wave) direction, time (symbol) direction.Below, this pilot frequency carrier wave is called SP (scattered pilot, Scattered Pilot).During the transmission line property of the symbol of representing with arrow in interpolation, for the carrier wave that has inserted the SP that represents with black circle, can receive SP to this and directly carry out interpolation as transmission line property, but, carrier wave (data carrier) for the grey circle of the usefulness that does not dispose SP is represented need carry out interpolation from the SP of front and back reception in time.
The present invention relates to the mode of this interpolation algorithm, and the interpolation mode of being used at present to adopt is elaborated.
Because SP decentralized configuration, so, narrated in front for the carrier wave that does not have SP and need carry out interpolation, but as the interpolation mode of this time orientation, used as shown in Figure 4 interpolation or zero degree hold mode (Japanese is " 0 ホ one Le De mode ") usually from the SP of front and back.
Interpolation is the mode of the front and back SP as the symbol of interpolation object being carried out the interpolation interpolation with straight line, and it is mode with substitute the SP that carries out interpolation in time with the SP of the immediate symbol of symbol that becomes the interpolation object that zero degree keeps.
According to the interpolation mode of above explanation, use SP interpolation transmission line property, from the 25 output interpolation transmission line property h of transmission line property interpolation portion (t, k).
In balanced portion 26, for in order to compensate the output signal of the delay correction portion 24 that is provided with the delay of transmission line property interpolation portion 25, with interpolation transmission line property h (t, k) carry out plural number and remove calculation, thereby the balance (being wave shape equalization) of carrying out amplitude, phase place (perhaps, replace the wave shape equalization of balanced portion, and it is synthetic to be based on interpolation transmission line property execution diversity (diversity)).
The signal of balance carries out IFFT by modulation portion 27 again and handles like this, is converted to the time shaft signal once more, generates OFDM at interval by supplementary protection and sends signal.OFDM sends signal and carries out analog-converted by D/A28, utilizes the channel different with receiving channels to send from transmitting antenna 28.
Below, represent the structure of SFN repeater at Fig. 5, and use this figure that the feature of SFN repeater is described.
The signal that receives by reception antenna 21 through A/D22, sef-adapting filter 51, and D/A28 send from transmitting antenna 29.At this, transmission frequency is identical with receive frequency, so from the part of the signal of transmitting antenna 29 output, as disturbing (Japanese be " a Hui り Write body ") arrival reception antenna 21.In sef-adapting filter 51,, eliminate this interference by controlling filter factor adaptively.As being suitable for the maximum reason that sef-adapting filter carries out wave shape equalization, can exemplify the shortening technology in the propagation delay time from the reception antenna to the transmitting antenna in the time shaft zone.This be because, if received signal and to send time of delay of signal elongated, the transfer function instability of repeater integral body then, the probability that produces wave distortion and vibration etc. increases.For head it off, need shorten the time of delay from the reception antenna to the transmitting antenna as far as possible.
As the filter factor update mode, by FFT portion 23 output signal of sef-adapting filter 51 is converted to the frequency axis signal, carry out the interpolation of aforesaid transmission line property in transmission line interpolation portion 25.Calculate the SP signal of interpolation and the residual error error between the known SP signal in Error Calculation portion 52, be converted to the time shaft signal once more from the frequency axis signal in IFFT portion 53.
In filter factor renewal portion 54 update coefficients successively, make the residual error error become minimum.By such processing, the inverse function of the transmission line function from the transmitting antenna to the reception antenna is formed by sef-adapting filter, can eliminate interference signal.
And, in the OFDM receiver, at first carry out interpolation in frequency direction, also carry out extrapolation one time at time orientation then, come the interpolation transmission line property.
Non-patent literature 1: map information medium association magazine Vol.52 in 1998, No.11
Patent documentation 1: TOHKEMY 2002-300094 communique
The repeater of above-mentioned explanation is used in fixedly loop, and the antenna in the time of can be because of reflected wave or storm rocks the fluctuation that waits the generation received signal.The fluctuation of this received signal becomes the fluctuation of transmission line property.And, the MFN repeater, and the SFN repeater in, from receiving SP interpolation transmission line transfer function, the contrary characteristic of the characteristic by being multiplied by interpolation compensates.But under the situation in the time orientation interpolation of the SP that has carried out aforesaid zero degree hold mode under the many environment of such fluctuation, it is big that the error of the transmission line property of interpolation becomes, and equalization characteristic can worsen.And, in the interpolation mode that has used an interpolation method, carry out interpolation, therefore the delay that produces three symbols at least at interval at the SP of four symbols that are used in the received terrestrial digital broadcasting mode from the SP of front and back.In the parameter of received terrestrial digital broadcasting mode, the about 1ms of 1 symbol, the therefore delay that has produced 3ms.
In the MFN repeater, be attached to this time of delay on the main line path of repeater, in the demanding system of low delayization, can not ignore.And, in the SFN repeater, when having produced the high speed fluctuation of transmission line property, become the main cause that reduces the stability of a system this time of delay because of the high speed fluctuation of in the coefficient update of sef-adapting filter, using the interpolation transmission line property.That is, if comprise the delay key element in the feedback loop that forms for coefficient update, then this system's loss of stability can exemplify out the shortcoming that can vibrate under the worst case.
Moreover, need the data of several symbols of storage front and back, so can also exemplify the shortcoming that memory span increases, hardware size also increases that needs.
And, during from the transmission line property of the symbol that do not dispose SP in the interpolation of the reception SP of time orientation decentralized configuration signal, reception SP from front and back on the time orientation of the symbol that becomes the interpolation object carries out the interpolation interpolation, carry out extrapolation one time by time orientation then, carried out the interpolation of transmission line property at symbol.But, formerly carry out in this temporally interpolated mode, produced the problem of the time of delay of several symbols can take place.
Summary of the invention
In the present invention, as first method for the above-mentioned problem of solution, be to receive the known pilot frequency carrier wave of amplitude and phase place in the OFDM of the ofdm modulation signal of time orientation decentralized configuration receiving system, to the individual reception pilot frequency carrier wave of q (q is an integer) that receives in during the individual symbol of p (p is an integer) in the past, after multiply by independently predetermined coefficients respectively, synthetic result separately in the time orientation extrapolation, carries out interpolation with the transmission line property of symbol that do not dispose pilot frequency carrier wave.
As second method, above-mentioned time extrapolation mode by to the symbol time that becomes the interpolation object on 2 pilot frequency carrier waves receiving constantly of nearest past carry out extrapolation one time, the transmission line property of the symbol of pilot frequency carrier wave is not disposed in interpolation.
As third party's method, above-mentioned time extrapolation mode, for with the symbol time that becomes the interpolation object on 3 pilot frequency carrier waves receiving constantly of nearest past, after respectively the vector between pilot tone being multiply by predetermined coefficients, synthetic result separately, the transmission line property of symbol that do not dispose pilot frequency carrier wave in the time orientation extrapolation, is carried out interpolation.
Moreover, utilize the OFDM receiver and the OFDM repeater that possess the transmission line interpolation mode that adopts the aforesaid first extrapolation mode to the, three extrapolation modes.
The present invention when the interpolation transmission line property, multiply by different predetermined coefficients respectively on a plurality of reception SP of Jie Shouing in the past after, synthetic result separately carries out extrapolation process at time orientation, can realize the shortening of time of delay thus.
Carry out also can realizing the shortening of relay delay time in the broadcast ripple relay of relaying at the reception broadcast wave, can also follow the trail of the fast received signal of velocity of wave motion.
A kind of OFDM method of reseptance, it is characterized in that, receiving the known pilot frequency carrier wave of amplitude and phase place in the OFDM receiving system of the ofdm modulation signal of frequency direction and time orientation decentralized configuration, data transmission link characteristic to q reception pilot frequency carrier wave receiving in during p symbol in the past, multiply by independently predetermined coefficients respectively, after separately result carried out complex addition, data transmission link characteristic to the data carrier that do not dispose pilot frequency carrier wave on time orientation is carried out the extrapolation interpolation, p wherein, q is an integer, above-mentioned time extrapolation interpolation is for 3 pilot frequency carrier waves that receive constantly with approaching past of the symbol that becomes the interpolation object in time, after on each pilot vector, multiply by predetermined coefficients, individual result is separately carried out complex addition, and extrapolation is carried out the extrapolation interpolation to the transmission line property of the symbol that do not dispose pilot frequency carrier wave on time orientation.
A kind of OFDM receiving system, be the OFDM receiving system of the known pilot frequency carrier wave of reception amplitude and phase place at the ofdm modulation signal of frequency direction and time orientation decentralized configuration, it is characterized in that, has following broadcast wave relay function: to the data transmission link characteristic of q reception pilot frequency carrier wave receiving in during p symbol in the past, multiply by independently predetermined coefficients respectively, result is separately carried out complex addition, carry out based on wave shape equalization the data transmission link characteristic transmission line property interpolation that the extrapolation interpolation is carried out on time orientation of the data carrier that do not dispose pilot frequency carrier wave, some in perhaps assembling based on the branch of the transmission line property interpolation that utilizes above-mentioned time extrapolation interpolation, signal or branch assemble the back signal and are converted to modulation signal once more after should equilibrium, send once more as broadcast wave, p wherein, q is an integer, in this OFDM receiving system, include time extrapolation transmission line property interpolation portion, this time extrapolation transmission line property interpolation portion is for 3 pilot frequency carrier waves that receive constantly with approaching past of the symbol that becomes the interpolation object in time, after on each pilot vector, multiply by predetermined coefficients, each result is carried out the complex addition computing, and the transmission line property to the symbol that do not dispose pilot frequency carrier wave on time orientation carries out the extrapolation interpolation.
A kind of OFDM receiving system, be the OFDM receiving system of the known pilot frequency carrier wave of reception amplitude and phase place at the ofdm modulation signal of frequency direction and time orientation decentralized configuration, it is characterized in that, has following broadcasting relay function: receive the broadcast wave signal with reception antenna, to having received q data transmission link characteristic that receives pilot frequency carrier wave of received signal in during p symbol in the past, multiply by independently predetermined coefficients respectively, result is separately carried out the complex addition computing, on time orientation, carry out the transmission line property interpolation of extrapolation interpolation based on the data transmission link characteristic of the data carrier that will not dispose pilot frequency carrier wave, carry out wave shape equalization, signal after the wave shape equalization is sent as broadcast wave once more, p wherein, q is an integer, in this OFDM receiving system, include time extrapolation transmission line property interpolation portion, this time extrapolation transmission line property interpolation portion is for 3 pilot frequency carrier waves that receive constantly with approaching past of the symbol that becomes the interpolation object in time, after on each pilot vector, multiply by predetermined coefficients, each result is carried out complex addition, and the transmission line property to the symbol that do not dispose pilot frequency carrier wave on time orientation carries out the extrapolation interpolation.
Description of drawings
Fig. 1 is the block diagram of the structure of the expression first embodiment of the present invention.
Fig. 2 is the block diagram of the structure of expression MFN repeater.
Fig. 3 is the ideograph of the configuration of expression SP.
Fig. 4 is the block diagram of the interpolation mode of expression transmission line property.
Fig. 5 is the block diagram of the structure of expression SFN repeater.
Fig. 6 is the block diagram of the structure of expression time extrapolation transmission line property interpolation of the present invention portion 11.
Fig. 7 is the ideograph of the action specification figure of expression SP extraction unit 65 of the present invention.
Fig. 8 is the ideograph of the interpolation mode that begins of the expression reception SP of ordering from the bright i of this law.
Fig. 9 is the ideograph that expression utilizes the interpolation mode of an extrapolation of the present invention.
Figure 10 is expression from 3 the of the present invention ideographs that receive the interpolation mode that SP begin.
Figure 11 is the block diagram of the structure of the expression second embodiment of the present invention.
Embodiment
Utilize Fig. 1 to describe the first embodiment of the present invention in detail.And structure shown in Figure 1 is, transmission line property interpolation portion 25 replaced with the structure of time extrapolation transmission line property interpolation portion 11 in the MFN of prior art shown in Figure 2 repeater, in addition has identical functions.
At first, sample by A/D22, obtain time shaft and receive sampled value series from the signal that reception antenna 21 receives.Be provided with on the time shaft signal time window that symbol is interfered does not take place, the signal in the time window is converted to frequency axis signal r (t, r) (wherein, the t is-symbol is numbered, and k is a carrier index) by FFT portion 23.Frequency axis signal r (t k) is imported into time extrapolation transmission line property interpolation portion 11, calculate interpolation transmission line property h (t, k).
The present invention relates to this time extrapolation transmission line property interpolation portion 11, explain the function of time extrapolation transmission line property interpolation portion 11 below.
The structure of Fig. 6 express time extrapolation transmission line property interpolation portion 11.(t k) is imported into delay portion 61 and SP extraction unit 65 from the frequency axis signal r of FFT portion 23.Output delay portion 61 with frequency axis signal r (t, k) postponed a symbol signal r (t-1, k).(t-1 k) is input to delay portion 62 to the output signal r of delay portion 61, and is input to SP extraction unit 65.The action of delay portion 62 is actions identical with delay portion 61, output delay the signal r of two symbols (t-2, k).Equally, from delay portion 63,64 output delaies of delay portion the signal r of three symbols (t-3, k) and postponed N symbol signal r (t-N, k).
Because at the time of back level extrapolation portion 66 SP carrier wave interpolation transmission line properties from reception, therefore, SP extraction unit 65 from as the output signal of delay portion 61～64, current time or the frequency axis signal that receives constantly in the past, extract the SP carrier wave out and export.Specifically, for example be four symbols at interval if establish the insertion of the time orientation of SP carrier wave, then always the signal r of self-dalay portion 61～64 (t, k), r (t-1, k), r (t-2, k), r (t-3, k) ... r (t-N, k) the SP signal of Chou Chuing becomes,
R (t ', k), r (t '-4, k), r (t '-8, k), r (t '-12, k) ... r (t '-4 * I, k) formula (1).
At this, when the interpolation object is k carrier wave constantly at the t symbol, t ' expression in the past in N symbol, have SP near symbol moment of t.And the SP of extraction is the signal that receives in the past, so become the condition of t '≤0.
Using Fig. 7 illustrative examples such as carrier index is 6 (k=6), the example when symbol number is 0 (t=0).Among the carrier wave r (0,6) that arrow is represented, be in t=-2 constantly at the nearest symbol that receives SP in the past in the drawings, therefore the t ' in formula (1) becomes t '=-2.Because example has disposed the example of SP with per four symbols, therefore, become r (2,6), r (6,6), r (10,6), r (14,6) by the SP of SP extraction unit 65 extractions ...
Equally, carrier index is 12 (k=12), the SP signal extracted out when symbol number is 0 (t=0) becomes r (0,12), r (4,12), r (8,12), r (12,12) ...
In SP extraction unit 65, the SP signal that input is extracted out by formula (1) is to time extrapolation portion 66.In time extrapolation portion 66, carry out the interpolation of t symbol transmission line property constantly based on the SP signal of extracting out.Therefore, to predetermined coefficients on each SP signal times of extracting out, with their complex addition result as interpolation SP signal.If interpolation SP signal be r ' (t, k), when the predetermined coefficients that multiplies each other is α, become,
R ' (t, k)=∑ α i* r (t '-4 * i, k) formula (2).
Utilize Fig. 8 to illustrate in greater detail them.
Fig. 8 is the figure that expression receives SP and interpolation SP on complex number plane.Black circle is represented the SP carrier wave in past of being extracted out by the SP extraction unit, and white circle represents to suppose the desirable SP acceptance point when the t symbol as the interpolation object has received SP constantly.The SP signal of formula (2) interpolation represented to utilize in asterisk.And solid line is represented transmission line property in the past, and chain-dotted line is represented following transmission line property.By on the SP signal of representing with black circle, being multiplied by predetermined coefficients α respectively i, carry out complex addition, will calculate as interpolation SP with the signal that asterisk is represented.At this moment, because noise contribution and the at a high speed influence of fluctuation for the desirable SP signal of representing with white circle the interpolation error percentage take place sometimes, but those influence under the little situation, can make this interpolation error percentage become minimum level.
Below, the specific design example of predetermined coefficients α is described.
At first, as first concrete example, utilize Fig. 9 that the extrapolation mode is described one time.
This is to be 2 to the maximum by the SP quantity that the SP extraction unit is extracted out, connects these SP signals and the mode of configuration interpolation SP signal on its extended line with straight line.Therefore, will be by the received terrestrial digital broadcasting mode of per four symbol decentralized configuration as an example the time, (t k) can realize by the calculating of execution formula (3) the interpolation SP signal r ' that represents with asterisk.
r’(t，k)＝r(t’，k)+c/4×[r(t’，k)-r(t’-4，k)]
Formula (3)
At this, c has the relation of c=t-t ', expression r (t, k) and r (t ', k) c symbol apart.Disperse among the SP at four symbols, c gets 0 to 3 coefficient.
Represent second concrete example at Figure 10.The quantity maximum that is the SP of extraction is made as 3, goes out the mode of interpolation SP from these SP calculated signals.In the mode of first concrete example, when the velocity of wave motion of transmission line property was slow, the interpolation error diminished, but along with velocity of wave motion is accelerated, the margin of error increases.Therefore, in second concrete example, purpose is by reception SP more first on service time, also carries out high-precision interpolation in the fast environment of velocity of wave motion.The general expression of this second mode multiply by factor alpha as the formula (4) on three SP signals 0～α 2Afterwards, synthesize.
r’(t，k)＝α 0×r(t’，k)+α 1×r(t’-4，k)+α 2×r(t’-8，k)
Formula (4)
Factor alpha 0～α 2Selected can consider various values, as being suitable for the value that per four symbols have disposed the received terrestrial digital broadcasting mode of SP carrier wave, can consider formula (5), formula (6) etc.
α 0=1, α 1=0, α 2=0 (during c=0)
α 0=11/8, α 1=-4/8, α 2=1/8 (during c=1)
α 0=14/8, α 1=-8/8, α 2=2/8 (during c=2)
α 0=17/8, α 1=-12/8, α 2=3/8 (during c=3)
Formula (5)
α 0=1, α 1=0, α 2=0 (during c=0)
α 0=12/8, α 1=-6/8, α 2=2/8 (during c=1)
α 0=16/8, α 1=-12/8, α 2=4/8 (during c=2)
α 0=20/8, α 1=-18/8, α 2=6/8 (during c=3)
Formula (6)
Like this, by the SP signal r that extracts out (t ', k), r (t '-4, k), (coefficient shown in formula (4)～(6) be multiply by on k) in t '-8 to r, and (t k) calculates as interpolation SP signal r ' with the value shown in the asterisk among the figure.
In time extrapolation portion 66, also can utilize the interpolation mode of above explanation that the carrier wave that does not dispose SP is carried out high accuracy and undelayed interpolation.In the parameter of received terrestrial digital broadcasting mode, the SP that utilizes this interpolation to per 12 carrier waves configuration can be become per 3 carrier waves of equal valuely.
In frequency interpolation portion 67, by (for example being provided with to the SP carrier wave by time extrapolation interpolation, the carrier wave 0,3,6 of Fig. 7 ...) between carrier wave (for example, the carrier wave 1,2,4,5,7,8 of Fig. 7 ...) fir filter interpolator that carries out interpolation, interpolation do not dispose the data carrier of SP transmission line property h (t, k).As this fir filter interpolator, use the FIR filter of high-order usually, even but a straightforward procedure such as interpolation also can realize.
And according to sampling thheorem, the SP carrier spacing of equal value is close more, just can balanced multipath to the long delay time.On the principle, the multipath up to time of delay shown in the formula (7) can carry out equilibrium.
Can the balanced delayed time of multichannel [sampling]
=significant character length [sampling]/SP carrier spacing formula of equal value (7)
Therefore, as described above, carry out the extrapolation of time orientation, and make the SP carrier spacing of equal value become close, carry out the interpolation interpolation of frequency direction again, thus, balanced multichannel warp to the long delay time.
By the time extrapolation transmission line property interpolation portion 11 of above explanation calculate interpolation transmission line property h (t, k).
Delay correction portion 24 shown in Figure 1, balanced portion 26, the function of modulation portion 27, D/A28, transmitting antenna 29 is identical with function shown in Figure 2 again, therefore in this description will be omitted.
Then, use Figure 11 that the second embodiment of the present invention is described.Second embodiment has been suitable for the interpolation mode that utilizes the transmission line property that time extrapolation of the present invention carries out in the SFN repeater, so, as interpolation mode with identical in the content of first embodiment explanation.
Structure shown in Figure 11 is, transmission line property interpolation portion 25 replaced with the structure of time extrapolation transmission line property interpolation portion 11 in the SFN of prior art shown in Figure 5 repeater, has identical functions in addition.As mentioned above, in the SFN repeater, from the output of sef-adapting filter 51,, formed the feedback loop that is input to sef-adapting filter 51 once more via FFT portion 23, transmission line property interpolation portion 11, Error Calculation portion 52, IFFT portion 53 and filter factor renewal portion 54.When the velocity of wave motion of the input signal of sef-adapting filter 51 is fast, lose the stability in loop the time of delay of feedback loop, the signal degradation of generation vibration etc.Therefore, the interpolation mode of the transmission line property that utilizes the time extrapolation of the application of the invention can shorten time of delay, also can follow the trail of the fast signal of velocity of wave motion.
And the scope of application of the present invention is except first, second embodiment, in directionality control repeater that can also be applicable to the diversity repeater that possesses a plurality of antennas, utilizes adaptive antenna array or the simple receiver.

Claims (4)

1. an OFDM method of reseptance is characterized in that, is receiving the known pilot frequency carrier wave of amplitude and phase place in the OFDM receiving system of the ofdm modulation signal of frequency direction and time orientation decentralized configuration,
Data transmission link characteristic to q reception pilot frequency carrier wave receiving in during p symbol in the past, multiply by independently predetermined coefficients respectively, after separately result carried out complex addition, data transmission link characteristic to the data carrier that do not dispose pilot frequency carrier wave on time orientation is carried out the extrapolation interpolation, wherein p, q are integers
Above-mentioned time extrapolation interpolation is for 3 pilot frequency carrier waves that receive constantly with approaching past of the symbol that becomes the interpolation object in time, after on each pilot vector, multiply by predetermined coefficients, each result is carried out complex addition, and the transmission line property to the symbol that do not dispose pilot frequency carrier wave on time orientation carries out the extrapolation interpolation.
2. OFDM method of reseptance as claimed in claim 1 is characterized in that,
After having carried out above-mentioned time extrapolation interpolation, carry out the interpolation interpolation in frequency direction.
3. an OFDM receiving system is the OFDM receiving system of the known pilot frequency carrier wave of reception amplitude and phase place at the ofdm modulation signal of frequency direction and time orientation decentralized configuration, it is characterized in that,
Has following broadcast wave relay function: to the data transmission link characteristic of q reception pilot frequency carrier wave receiving in during p symbol in the past, multiply by independently predetermined coefficients respectively, result is separately carried out the complex addition computing, carry out the wave shape equalization of the transmission line property interpolation carried out in the interpolation of time orientation extrapolation based on the data transmission link characteristic of the data carrier that will not dispose pilot frequency carrier wave, some in perhaps assembling based on the branch of the transmission line property interpolation that utilizes above-mentioned time extrapolation interpolation, signal or branch assemble the back signal and are converted to modulation signal once more after should equilibrium, send once more as broadcast wave, p wherein, q is an integer
In this OFDM receiving system, include time extrapolation transmission line property interpolation portion, this time extrapolation transmission line property interpolation portion is for 3 pilot frequency carrier waves that receive constantly with approaching past of the symbol that becomes the interpolation object in time, after on each pilot vector, multiply by predetermined coefficients, each result is carried out complex addition, and the transmission line property to the symbol that do not dispose pilot frequency carrier wave on time orientation carries out the extrapolation interpolation.
4. an OFDM receiving system is the OFDM receiving system of the known pilot frequency carrier wave of reception amplitude and phase place at the ofdm modulation signal of frequency direction and time orientation decentralized configuration, it is characterized in that,
Has following broadcast relay function: receive the broadcast wave signal with reception antenna; To having received q data transmission link characteristic that receives pilot frequency carrier wave of signal in during p symbol in the past; Multiply by respectively independently predetermined coefficients; Result is separately carried out the complex addition computing; Carry out the transmission line property interpolation of extrapolation interpolation at time orientation based on the data transmission link characteristic of the data carrier that will not dispose pilot frequency carrier wave; Carry out wave shape equalization; Signal after the wave shape equalization is sent as broadcast wave again; Wherein p, q are integers
In this OFDM receiving system, include time extrapolation transmission line property interpolation portion, this time extrapolation transmission line property interpolation portion is for 3 pilot frequency carrier waves that receive constantly with approaching past of the symbol that becomes the interpolation object in time, after on each pilot vector, multiply by predetermined coefficients, each result is carried out complex addition, and the transmission line property to the symbol that do not dispose pilot frequency carrier wave on time orientation carries out the extrapolation interpolation.
CN2006101515142A 2005-09-12 2006-09-12 OFDM reception method and apparatus Expired - Fee Related CN1933471B (en)

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JP2005263300A JP2007081504A (en) 2005-09-12 2005-09-12 Transmission path characteristic interpolation method in ofdm receiver and apparatus thereof
JP263300/2005 2005-09-12

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CN1933471A CN1933471A (en) 2007-03-21
CN1933471B true CN1933471B (en) 2010-10-13

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