CN102257752B - Receiver apparatus and symbol timing determining method - Google Patents

Abstract

A window function generating unit (21) extracts a left half section (T11) of a window function to generate a left section window function. The window function generating unit (21) then subtracts the left section window function from 1 to generate a right section window function. A processed signal generating unit (22) generates a first processed signal (S1) by multiplying a received signal by the left section window function (wk) in time series in such a manner that the starting point is set to a time point (TB) of the received signal that is past by the finite section of the left section window function from a time point (TO) that is past by a reference time interval from a given reference time point (TR). The processed signal generating unit (22) also generates a second processed signal (S2) by multiplying the received signal by the right section window function (1 - wk) in time series in such a manner that the starting point is set to a time point of the received signal that is past by the finite section of the right section window function from the reference time point (TR). An output unit (23) outputs a signal, which is obtained by adding the first processed signal (S1) to the second processed signal (S2) in time series, to a timing determining unit (3) as a received signal of a time interval (TI) from the reference time point (TR) to a time point just before the finite section of the right section window function (1 - wk).

Description

Receiving system and method for detecting symbol timing

Technical field

The present invention relates to receiving system and method for detecting symbol timing that the Symbol Timing of the multi-carrier signal (multi-carrier signal) to comprising the front pilot (preamble portion) that known symbol repeats detects.

Background technology

Take in OFDM (the OFDM:Orthogonal Frequency Division Multiplexing) communication mode that IEEE802.11a is representative, in detected symbol, adopting the relevant treatment of the time shaft oscillogram (time axis wave pattern) of having used known symbol regularly time.Figure 12 is the frame assumption diagram of ofdm signal of a grouping of IEEE802.11a.In addition in the following description, for convenience of explanation, ignore at the additional noise of transmission path.

As shown in figure 12, this ofdm signal comprises front pilot D1, letter head (header portion) D2 and data portion D3.Front pilot D1 comprises short front pilot D11 and the D12 of long preambles portion.Short front pilot D11 repeated storage is called the known symbol of Short Training symbol (STS:Short Training Symbol).The D12 of long preambles portion repeated storage is called the known symbol of long training symbol (LTS:Long Training Symbol).In addition, in IEEE802.11a, STS repeats 10 times, and LTS repeats 2 times.

And in receiving system in the past, the time shaft oscillogram of pre-stored STS, by obtaining this time shaft oscillogram and the correlation of reception signal of input chronologically, comes detected symbol regularly.

Figure 13 represents the block diagram of the sync detection circuit of the detected symbol timing in receiving system in the past.As shown in figure 13, sync detection circuit comprises correlator 101, known symbol storage part 102, peak value test section 103, threshold value storage part 104, timing detection unit 105, counter 106 and OFDM demodulator circuit 107.

The processing of correlator 101 is described below.If the time shaft oscillogram of STS is s _k, to receive signal be s ' k, correlation Rxx (l) represents with formula (1).

[formula 1]

$\mathrm{Rxx}\left(l\right)=\underset{k=0}{\overset{N-1}{\mathrm{\Σ}}}{s}_k^{\′}\·{s^{*}}_{k+l}---\left(1\right)$

Wherein, " * " represents complex conjugate (complex conjugate), k represents the sample number of the sampled value in time domain (time domain), N represents the hits of the FFT size (FFT size) of ofdm signal, and l represents the slip number (slide number) of the time shaft oscillogram of STS.The in the situation that of IEEE802.11a, it is prerequisite that the hits of FFT size be take 64 fast Fourier transform (Fourier transform), thereby the time shaft oscillogram s of STS _kas shown in formula (2).

[formula 2]

$s_k=\underset{n=0}{\overset{63}{\mathrm{\&Sigma;}}}{a}_{\mathrm{<figure-callout\; id="2"\; label="n\; e\; j"\; filenames="HPA00001390193200031.png,HPA00001390193200041.png"\; state="\{\{state\}\}">n</figure-callout>}}{e}^j{\frac{2\mathrm{\&pi;nk}}{64}}^{}---\left(2\right)$

Wherein, n represents the sample number of the sampled value in frequency domain (frequency domain), a _nrepresent Fourier coefficient.

And in IEEE802.11a, the cycle of STS is 1/4 of FFT size, so the time shaft oscillogram s of STS _kwith formula (3), represent.

[formula 3]

$s_k=\underset{n=0}{\overset{64/4-1}{\mathrm{\&Sigma;}}}{a}_{4\mathrm{<figure-callout\; id="2"\; label="n\; e\; j"\; filenames="HPA00001390193200031.png,HPA00001390193200041.png"\; state="\{\{state\}\}">n</figure-callout>}}{e}^j{\frac{2\mathrm{\&pi;}4\mathrm{<figure-callout\; id="64"\; label="nk"\; filenames="HPA00001390193200041.png"\; state="\{\{state\}\}">nk</figure-callout>}}{64}}^{}=\underset{n=0}{\overset{15}{\mathrm{\&Sigma;}}}{a}_{4\mathrm{<figure-callout\; id="2"\; label="n\; e\; j"\; filenames="HPA00001390193200031.png,HPA00001390193200041.png"\; state="\{\{state\}\}">n</figure-callout>}}{e}^j{\frac{2\mathrm{\&pi;nk}}{16}}^{}---\left(3\right)$

Receive signal s ' _kbe subject to the impact of the distortion (distortion) of transmission path, therefore when establish distortion frequency domain be expressed as H _4ne ^{j θ 4n}time, receive signal s ' _kwith formula (4), represent.

[formula 4]

$s_k^{\&prime;}=\underset{n=0}{\overset{15}{\mathrm{\&Sigma;}}}{H}_{4n}{e}^{j{\mathrm{\&theta;}}_{4n}}{a}_{4\mathrm{<figure-callout\; id="2"\; label="n\; e\; j"\; filenames="HPA00001390193200031.png,HPA00001390193200041.png"\; state="\{\{state\}\}">n</figure-callout>}}{e}^j{\frac{2\mathrm{\&pi;nk}}{16}}^{}---\left(4\right)$

By after formula (3) and formula (4) substitution formula (1), the orthogonality based on Fourier transform, obtains formula (5).

[formula 5]

$R_{\mathrm{xx}}\left(l\right)=\underset{k=0}{\overset{63}{\mathrm{\&Sigma;}}}\left(\underset{m=0}{\overset{15}{\mathrm{\&Sigma;}}}{H}_{4m}{e}^{j{\mathrm{\&theta;}}_{4m}}{a}_{4\mathrm{<figure-callout\; id="2"\; label="m\; e\; j"\; filenames="HPA00001390193200031.png,HPA00001390193200041.png"\; state="\{\{state\}\}">m</figure-callout>}}{e}^j{\frac{2\mathrm{\&pi;mk}}{16}}^{}\underset{n=0}{\overset{15}{\mathrm{\&Sigma;}}}{a_{4n}}^{*}{e}^{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HPA00001390193200031.png,HPA00001390193200041.png"\; state="\{\{state\}\}">j</figure-callout>}\frac{2\mathrm{\&pi;n}(k+l)}{16}}\right)$

$=\underset{k=0}{\overset{63}{\mathrm{\&Sigma;}}}\left(\underset{n=0}{\overset{15}{\mathrm{\&Sigma;}}}\underset{m=0}{\overset{15}{\mathrm{\&Sigma;}}}{H}_{4m}{e}^{j{\mathrm{\&theta;}}_{4m}}{a}_{4m}{a_{4n}}^{*}{\mathrm{<figure-callout\; id="2"\; label="e\; j"\; filenames="HPA00001390193200031.png,HPA00001390193200041.png"\; state="\{\{state\}\}">e</figure-callout>}}^j{e}^{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HPA00001390193200031.png,HPA00001390193200041.png"\; state="\{\{state\}\}">j</figure-callout>}\frac{2\mathrm{\&pi;nl}}{16}}\right)$

$=\left\{\begin{array}{c}\underset{n=0}{\overset{15}{\mathrm{\&Sigma;}}}{H}_{4n}{e}^{j{\mathrm{\&theta;}}_{4n}}{\left|a_{4n}\right|}^2\&CenterDot;\&CenterDot;\&CenterDot;[l=16l^{\&prime;}]\\ 0\&CenterDot;\&CenterDot;\&CenterDot;[l\&NotEqual;16l^{\&prime;}]\end{array}\right.---\left(5\right)$

Wherein, l ' is more than 0 positive integer.And, in formula (5), during m ≠ n, irrelevant with n, about the aggregate value of k, based on orthogonality, become 0.In addition, in formula (5), about the correlation of n, be similarly 0 when l ≠ 16l '.

Its result, Rxx (l) is sampled as the cycle with 16 and has correlation (correlation value).Peak value test section 103 shown in Figure 13, in order not detect noise, compares the threshold value of appointment and correlation, and the correlation that surpasses threshold value is judged to be to correlation peak.

Regularly detection unit 105 is counted the peak period of 106 pairs of peak value test section 103 detected correlation peaks of counter, according to count value, detects Symbol Timing.

OFDM demodulator circuit 107 is according to the detected Symbol Timing of timing detection unit 105, demodulated received signal.

In addition, as the known document being associated, known patent document 1,2.In patent documentation 1, the receiver of following object is disclosed, in the situation that utilizing OFDM transmit information signals, for demodulate transmitted signal correctly in receiver, and make the frequency translation of transmitter and receiver consistent accurately by the frequency of oscillation of oscillator and the cycle of the sampling timing of transmitter and receiver.

In addition, in patent documentation 2, disclose in the situation that use the frequency pilot sign (pilot symbol) that gap carrier wave (null sub-carrier) is not set, also can establish reliably at short notice the digital communication apparatus of Frequency Synchronization.

But, receiving signal s ' _kcomprise disturbing wave am _ksituation under, can not correctly synchronously detect.To disturbing wave am _kcarry out Fourier expansion, obtain formula (6).

[formula 6]

${\mathrm{am}}_k=\underset{n=0}{\overset{L-1}{\mathrm{\&Sigma;}}}{\mathrm{AM}}_n{e}^{j{\mathrm{\&Theta;}}_{\mathrm{<figure-callout\; id="2"\; label="n\; e\; j"\; filenames="HPA00001390193200031.png,HPA00001390193200041.png"\; state="\{\{state\}\}">n</figure-callout>}}}{e}^j{\frac{2\mathrm{\&pi;nk}}{L}}^{}---\left(6\right)$

Wherein, AM _nthe complex amplitude (complex amplitude) that represents disturbing wave, e ^{j Θ n}the complex phase (complex phase) that represents disturbing wave, L represents the block size (block size number) of Fourier expansion.Disturbing wave am _kdo not have and be equivalent to the frequency f of self _aMfrequency indices n ₀sampled value in frequency domain in addition, so formula (6) can be simplified as shown in formula (7).

[formula 7]

${\mathrm{am}}_k={\mathrm{AM}}_{n_0}{e}^{j{\mathrm{\&Theta;}}_{n_0}}{\mathrm{<figure-callout\; id="2"\; label="e\; j"\; filenames="HPA00001390193200031.png,HPA00001390193200041.png"\; state="\{\{state\}\}">e</figure-callout>}}^j---\left(7\right)$

Its result, at this disturbing wave am _kin situation about existing, receive signal s ' _kneed to change as shown in formula (8).

[formula 8]

$s_k^{\&prime;}+{\mathrm{am}}_k=\underset{n=0}{\overset{15}{\mathrm{\&Sigma;}}}{H}_{4n}{e}^{j{\mathrm{\&theta;}}_{4n}}{a}_{4\mathrm{<figure-callout\; id="2"\; label="n\; e\; j"\; filenames="HPA00001390193200031.png,HPA00001390193200041.png"\; state="\{\{state\}\}">n</figure-callout>}}{e}^j{\frac{2\mathrm{\&pi;nk}}{16}}^{}+{\mathrm{AM}}_{n_0}{e}^{j{\mathrm{\&Theta;}}_{n_0}}{\mathrm{<figure-callout\; id="2"\; label="e\; j"\; filenames="HPA00001390193200031.png,HPA00001390193200041.png"\; state="\{\{state\}\}">e</figure-callout>}}^j---\left(8\right)$

Study this reception signal s ' _k+ am _ktime shaft oscillogram s with STS _kbetween dependency relation.According to the orthogonality of Fourier transform, comprise disturbing wave am _kreception signal s ' _k+ am _kwith time shaft oscillogram s _kbetween correlation Rxx (l) with formula (9), represent.

[formula 9]

$\mathrm{Rxx}\left(l\right)=\underset{k=0}{\overset{63}{\mathrm{\&Sigma;}}}(s_k^{\&prime;}+{\mathrm{am}}_k){s^{*}}_{k+l}$

$=\underset{k=0}{\overset{63}{\mathrm{\&Sigma;}}}\{\underset{n=0}{\overset{15}{\mathrm{\&Sigma;}}}{H}_{4n}{e}^{j{\mathrm{\&theta;}}_{4n}}{a}_{4\mathrm{<figure-callout\; id="2"\; label="n\; e\; j"\; filenames="HPA00001390193200031.png,HPA00001390193200041.png"\; state="\{\{state\}\}">n</figure-callout>}}{e}^j{\frac{2\mathrm{\&pi;nk}}{16}}^{}\underset{m=0}{\overset{15}{\mathrm{\&Sigma;}}}{a^{*}}_{4m}{e}^{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HPA00001390193200031.png,HPA00001390193200041.png"\; state="\{\{state\}\}">j</figure-callout>}\frac{2\mathrm{\&pi;m}(k+l)}{16}}$

$+{\mathrm{AM}}_{n_0}{e}^{j{\mathrm{\&Theta;}}_{n_0}}{\mathrm{<figure-callout\; id="2"\; label="e\; j"\; filenames="HPA00001390193200031.png,HPA00001390193200041.png"\; state="\{\{state\}\}">e</figure-callout>}}^j\underset{m=0}{\overset{15}{\mathrm{\&Sigma;}}}{a^{*}}_{4-m}{e}^{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HPA00001390193200031.png,HPA00001390193200041.png"\; state="\{\{state\}\}">j</figure-callout>}\frac{2\mathrm{\&pi;m}(k+l)}{16}}\}$

$=\underset{n=0}{\overset{15}{\mathrm{\&Sigma;}}}{H}_{4n}{e}^{j{\mathrm{\&theta;}}_{4n}}{\left|a_{4n}\right|}^2{e}^{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HPA00001390193200031.png,HPA00001390193200041.png"\; state="\{\{state\}\}">j</figure-callout>}\frac{2\mathrm{\&pi;nl}}{16}}$

$+{\mathrm{AM}}_{n_0}{e}^{j{\mathrm{\&Theta;}}_{{\mathrm{<figure-callout\; id="0"\; label="n"\; filenames="HPA00001390193200041.png,HPA00001390193200071.png"\; state="\{\{state\}\}">n</figure-callout>}}_0}}\underset{k=0}{\overset{63}{\mathrm{\&Sigma;}}}\left\{{\mathrm{<figure-callout\; id="2"\; label="e\; j"\; filenames="HPA00001390193200031.png,HPA00001390193200041.png"\; state="\{\{state\}\}">e</figure-callout>}}^j\underset{m=0}{\overset{15}{\mathrm{\&Sigma;}}}{a^{*}}_{4m}{e}^{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HPA00001390193200031.png,HPA00001390193200041.png"\; state="\{\{state\}\}">j</figure-callout>}\frac{2\mathrm{\&pi;m}(k+l)}{16}}\right\}---\left(9\right)$

In formula (9), first shown in row second from the bottom with shown in formula (5), not there is not disturbing wave am _ksituation under correlation consistent, but second shown in row last becomes error, makes the detection performance degradation of Symbol Timing.Herein, in the error shown in second, disturbing wave am _kamplitude composition AMn ₀for main component, if disturbing wave am _kmodulated, according to its modulating frequency, change.And the error shown in second also changes according to the cycle of STS.

As mentioned above, at disturbing wave am _kin situation about existing, occur that the correlation of the error based on shown in second becomes large situation, make the Check processing difficulty of correlation peak, have the problem of the detection performance degradation of Symbol Timing.In addition, in the method for patent documentation 1,2, do not record the content that suppresses disturbing wave.

Patent documentation 1: No. 8-223132, Japanese Patent Publication communique Unexamined Patent

Patent documentation 2: No. 2000-22660, Japanese Patent Publication communique JP

Summary of the invention

Even if the object of the present invention is to provide a kind of receiving system and method for detecting symbol timing that also can detect accurately Symbol Timing in the situation that disturbing wave exists.

Receiving system involved in the present invention detects the Symbol Timing of the multi-carrier signal of the front pilot that comprises known symbol repetition, comprise: window function handling part, utilization has the window function of the finite interval shorter than the base period of the integral multiple in the cycle of described known symbol, carries out to received signal window function processing; And timing test section, obtain described window function handling part and carry out the correlation peak between the reception signal of window function processing and the time shaft oscillogram of described known symbol, based on this correlation peak, detect the Symbol Timing of described multi-carrier signal, wherein, described window function handling part comprises: window function generating unit, and the left-half interval or the right half part that take out described window function are interval, window function based on taking out, generates left interval window function and right interval window function; Processing signals generating unit, using moment of reception signal of finite interval of recalling the moment of described base period from the benchmark of appointment constantly and recalling described left interval window function again as starting point, described left interval window function is generated to the first processing signals with described reception signal multiplication chronologically, and using moment of described reception signal of the finite interval of recalling described right interval window function from described benchmark constantly as starting point, described right interval window function is generated to the second processing signals with described reception signal multiplication chronologically; And efferent, the reception signal of the signal that described the first processing signals and described the second processing signals are added chronologically till as date back the finite interval of described right interval window function constantly from described benchmark, exports described timing test section to.

In addition, method for detecting symbol timing involved in the present invention detects the Symbol Timing of the multi-carrier signal of the front pilot that comprises known symbol repetition, comprise the following steps: window function treatment step, utilizes the window function with the finite interval shorter than the base period of the integral multiple in the cycle of described known symbol to carry out to received signal window function processing; And timing detecting step, obtain the reception signal processed by described window function treatment step and the correlation peak between the time shaft oscillogram of described known symbol, and the Symbol Timing based on multi-carrier signal described in this correlation peak detection, wherein, described window function treatment step comprises the following steps: window function generates step, the left-half interval or the right half part that take out described window function are interval, and the window function based on taking out generates left interval window function and right interval window function; Processing signals generates step, using moment of reception signal of finite interval of recalling the moment of described base period from the benchmark of appointment constantly and recalling described left interval window function again as starting point, described left interval window function is generated to the first processing signals with described reception signal multiplication chronologically, and using from described benchmark, constantly recall described right interval window function moment of described reception signal of finite interval as starting point, described right interval window function is generated to the second processing signals with described reception signal multiplication chronologically; And output step, the signal that described the first processing signals and described the second processing signals are added chronologically, as the reception signal date back constantly the finite interval of described right interval window function from described benchmark till and export.

Accompanying drawing explanation

Fig. 1 represents the block diagram of the receiving system of embodiment of the present invention 1.

Fig. 2 means the oscillogram of an example of window function.

Fig. 3 means the block diagram of the detailed structure of the window function handling part shown in Fig. 1.

Fig. 4 is the key diagram that the window function of the window function handling part shown in Fig. 3 is processed.

Fig. 5 (a) is the concept map during by the number of reception signal plus FFT size that does not carry out window function processing, be (b) by carried out the reception signal plus FFT size that window function processes number time concept map.

Fig. 6 represents the block diagram of the receiving system of embodiment of the present invention 2.

Fig. 7 means the figure of result of calculation of the correlation of the correlator shown in Fig. 6.

Fig. 8 represents the block diagram of the receiving system of embodiment of the present invention 3.

Fig. 9 represents for the power spectrum of the subcarrier of the generation of STS (power spectra).

Figure 10 has represented to superpose and take the correlated results of reception signal of the disturbing wave that is carried out AM modulation that 3.4MHz is carrier wave.

Figure 11 has represented to superpose and take the correlated results of signal vector of the disturbing wave that is carried out AM modulation that 20.2MHz is carrier wave.

Figure 12 is the frame assumption diagram of multi-carrier signal of a grouping (packet) of IEEE802.11a.

Figure 13 represents the block diagram of the sync detection circuit of the detected symbol timing in receiving system in the past.

Embodiment

(execution mode 1)

Below, the receiving system of embodiment of the present invention 1 is described.Fig. 1 represents the block diagram of the receiving system of embodiment of the present invention 1.Receiving system shown in Fig. 1 is for example the receiving system of IEEE802.11a standard, is to receive the receiving system that carries out Digital Modulation and carry out the multi-carrier signal of multiplexing (multiplexing) have a plurality of subcarriers of the arrowband (narrow band) of orthogonality relation on frequency axis.

This multi-carrier signal is OFDM (Orthogonal Frequency Division Multiplexing, the OFDM) signal of IEEE802.11a standard, as shown in figure 12, comprises front pilot D1, letter head D2 and data portion D3.Front pilot D1 is for example that PLCP (Physical Layer Convergence Protocol, Physical layer convergence protocol) is leading, and storage receives synchronous symbol for establishing.Letter head D2 storage letter header.Data portion D3 storage sends the data symbol of object.

Front pilot D1 comprises short front pilot D11 and the D12 of long preambles portion.Short front pilot D11 storage is as the Short Training symbol (STS) of known symbol.The D12 of long preambles portion stores long training symbol (LTS).STS and LTS are respectively the symbols that receiver side is known.STS is mainly for detection of the sign synchronization of Symbol Timing and the coarse adjustment of AFC (Automatic Frequency Control, automatic frequency is controlled).LTS is mainly used in fine setting and the channel of AFC and infers.

In IEEE802.11a standard, 10 STS of short front pilot D11 storage, are 0.8 μ S during a STS.In addition, the D12 of long preambles portion stores 2 LTS, is 3.2 μ S during a LTS.And, in the present embodiment, use 10 STS detected symbol regularly.

Letter header for example comprises transmission speed and the data length of the data symbol of storing in data portion D3.

Data portion D3 for example comprises the OFDM symbol specifying number that holds data symbol D32 and the OFDM symbol specifying number that holds pilot signal (PS) D33.Each OFDM symbol comprises protection interval (GI:Guard Interval) D31 that is arranged on front end (leading end).GID31 is the redundant signals (redundant signal) arranging for fear of intersymbol interference.And, the signal of (in the situation that of PSD33 be PSD33 rear end certain during) during GID31 is copied (manifolding) data symbol D32 rear end certain.

For example, in IEEE802.11a standard, during data symbol D32, be 3.2 μ S, during GID31, be 0.8 μ S.

Turn back to Fig. 1, receiving system comprises acceptance division 1, window function handling part 2, timing test section 3, known symbol storage part 4 and OFDM demodulator circuit 5.

Acceptance division 1 receives signal via the transmission path of appointment, after carrying out the simulation process of appointment, and by carrying out analog digital conversion, the reception signal of generating digital (receiving vector).In the present embodiment, acceptance division 1 for example be take the mode that the hits of one-period of STS is 16 and is sampled to received signal.In addition, the reception signal storage during certain is in figure buffer slightly the past.

As transmission path, for example, can adopt any in wired or wireless.As wired, can adopt various order wires or for power line of power line transport communication etc.

Window function handling part 2 is used the window function of appointment to carry out to received signal window function processing.

Herein, window function w _khave the short finite interval T1 of base period doubly of positive integer in the cycle of the STS that is compared to known symbol, and have symmetrical time shaft waveform, along with more approaching the central authorities of finite interval, its value is larger.In addition window function w, _kmaximum be below 1.

In the present embodiment, reference period (should be base period) is cycle of STS 4 times, hits is 16 * 4=64.This reference period (should be base period) and FFT (Fast Fourier Transform, fast Fourier transform) size, the OFDM symbol period of removing GI equates.

In the present embodiment, as window function w _kfor example adopt Gaussian window (Gaussian window), but be not limited to this, also can adopt the various window functions such as rectangular window (rectangular window), Gaussian window, Hanning window (Hann window), Hamming window (Hamming window), Blackman window (Blackman window), kaiser window (Kaiser window), bartlett window (Bartlett window), window index (exponential window).

Fig. 2 (a), (b) mean the window function w adopting in present embodiment _kthe oscillogram of an example.Fig. 2 (a),

(b), in, the longitudinal axis represents window function w _kvalue, transverse axis represents the time.The window function w of Fig. 2 (a), (b) _kthe hits of finite interval T1 be 14 of even numbers.

As shown in Fig. 2 (a), (b), finite interval T1 represent from the sampled point PL of left end play till the sampled point PR of right-hand member during.In addition, the interval T11 of left-half is the interval of being stipulated by the sampled point of left-half in finite interval T1, and the interval T12 of right half part is the interval of being stipulated by the sampled point of right half part in finite interval T1.

In Fig. 2 (a), on the longitudinal axis, there is sampled point, the sampled point number in the left side the sampled point on the longitudinal axis is 7, the sampled point number on the right side the sampled point on the longitudinal axis is 6, the number left-right asymmetry of sampled point.Therefore, Fig. 2 (a) in the situation that, comprise from sampled point PL to the longitudinal axis sampled point that left side is nearest 7 sampled points during be the interval T11 of left-half, comprise that sampled point from the longitudinal axis is the interval T12 of right half part during 7 sampled points of sampled point PR.In addition, Fig. 2 (a) in the situation that, the value of the sampled point on the longitudinal axis is 1.

On the other hand, in Fig. 2 (b), do not have sampled point on the longitudinal axis, the sampled point number in longitudinal axis left side and the sampled point number on right side are 7, and the number left and right of sampled point equates.Therefore, Fig. 2 (b) in the situation that, comprise from sampled point PL to the longitudinal axis sampled point that left side is nearest 7 sampled points during be the interval T11 of left-half, comprise 7 sampled points from the nearest sampled point in longitudinal axis right side to sampled point PR during be the interval T12 of right half part.On the other hand, Fig. 2 (b) in the situation that, owing to there not being sampled point on the longitudinal axis, so the equal less than 1 of value of the nearest sampled point of the value of the nearest sampled point in longitudinal axis left side and longitudinal axis right side.

In Fig. 2 (a), (b), for convenience of explanation, only show 14 sampled points, in the following description, suppose to have p+1 sampled point in the interval T11 of left-half, in the interval T12 of right half part, have p+1 sampled point, have altogether 2p+2 sampled point.

Fig. 3 means the block diagram of the detailed structure of window function handling part 2.Fig. 4 (a), (b) are the key diagrams that the window function of window function handling part 2 is processed.As shown in Figure 3, window function handling part 2 comprises window function generating unit 21, processing signals generating unit 22 and efferent 23.

Window function generating unit 21 is taken out window function w _kthe interval T11 of left-half generate left interval window function w _k, and based on this left interval window function w _k, generate right interval window function 1-w _k.Herein, as shown in Fig. 2 (a), (b), window function generating unit 21 is taken out p+1 the sample point of the interval T11 of left-half, generates left interval window function w _k.And, establish left interval window function w _kthe value of each sample point be w _k, based on 1-w _k, generate right interval window function 1-w _k.

Therefore, in the case, left interval window function w _k, right interval window function 1-w _kfinite interval be the interval T11 of left-half.

In addition, as shown in Fig. 4 (a), processing signals generating unit 22 is usingd the moment TB of reception signal of finite interval that constantly recalls the moment TO of base period TR and recall left interval window function again from the benchmark of appointment as starting point, by left interval window function w _kwith reception signal multiplication, generate the first processing signals S1 chronologically.

In addition, as shown in Fig. 4 (a), processing signals generating unit 22 using from benchmark, constantly recall right interval window function TR moment of reception signal of finite interval as starting point, by right interval window function 1-w _kwith reception signal multiplication, generate the second processing signals S2 chronologically.

As shown in Fig. 4 (b), the signal of efferent 23 so that the first processing signals S1 and the second processing signals S2 are added chronologically, as from benchmark constantly TR to dating back to right interval window function 1-w _kfinite interval before till during the reception signal of T1, and be output in regularly test section 3.

In addition, window function handling part 2 is for example carried out above-mentioned processing by each sampling period.

Turn back to Fig. 1, regularly test section 3 is obtained by window function handling part 2 and is carried out the correlation peak between the time shaft oscillogram (time axis wave pattern) of reception signal and the STS of window function processing, based on this correlation peak, detect the Symbol Timing of multi-carrier signal.

Particularly, regularly test section 3 comprises correlator 31, peak value test section 32, threshold value storage part 33, timing detection unit 34 and counter 35.

Correlator 31 is obtained the correlation based on being carried out the dependency relation between the time shaft oscillogram of the STS of storage in the reception signal of window function processing and known symbol storage part 4, and is output in peak value test section 32.

Peak value test section 32 detects from the correlation peak of the correlation of correlator 31 outputs.Herein, (scope of b < between a), with interior, judges that this correlation is as correlation peak to peak value test section 32 in the situation that the assign thresholds a storing in threshold value storage part 33 from the correlation of correlator 31 output and assign thresholds b.Accordingly, can prevent using noise as correlation peak detection out.

Herein, threshold value a for example adopts the correlation obtaining at the reception signal that sends and be not applied disturbing wave from immediate transmitter to add the value after surplus to a certain degree.The correlation that the reception signal that accordingly, can make basis be coupled with the energy of disturbing wave obtains is invalid.In addition, threshold value b for example can adopt from transmitter farthest send and have can burbling noise signal the correlation that obtains of peaked reception signal.Accordingly, can get rid of the impact of noise, and synchronous sensitivity is maximized.

Regularly detection unit 34 is counted the hits of the peak intervals of 35 pairs of peak value test section 32 detected correlation peaks of counter.And regularly detection unit 34 is in the situation that repeatedly detect the peak intervals of 16 samplings of the one-period that is equivalent to STS of predetermined number of times, the detection that detects this initial correlation peak repeatedly detecting is used as Symbol Timing constantly.

The time shaft oscillogram of the pre-stored STS as known symbol of known symbol storage part 4.This time shaft oscillogram is the numerical data for example being represented by 16 sampled values.In addition the time shaft oscillogram of the pre-stored STS of known symbol, but be not limited to this, value of symbol that also can pre-stored frequency domain.In the case, can between known symbol storage part 4 and correlator 31, known symbol generating unit be set, this known symbol generating unit is carried out IFFT (Inverse Fast Fourier Transform to the value of symbol of the frequency domain of storage in known symbol storage part 4, invert fast fourier transformation) carry out axle oscillogram computing time, and be output in correlator 31.

OFDM demodulator circuit 5, according to the detected synchronization timing of timing detection unit 34, carries out from the OFDM demodulation process of the reception signal of acceptance division 1 output.Herein, OFDM demodulator circuit 5 carries out to received signal the removing of front pilot, FFT, phase place correction, with BPSK, QPSK etc., is carried out the processing such as the demodulation of complex symbol (complex symbol) of primary modulation and error correction.Accordingly, data symbol D32 is restored.

Then, the processing details of the receiving system shown in Fig. 1 is described.First, instructions window function handling part 2 is used the situation that the common window function of the window function in 64 sampling periods different from above-mentioned explanation is processed.

In window function is processed, generally speaking, calculate in advance and preserve the window function w of the hits measure-alike with the FFT of multi-carrier signal as object _k, go forward side by side and be about to this window function w _kprocess with inner product (inner product) that reception signal multiplies each other chronologically according to each sampling.When establishing the reception signal that is carried out this inner product processing, be s ' _k, and for convenience of explanation, when the transfer function of supposing transmission path is l, s ' _kwith formula (10), represent.

[formula 10]

$s_k^{\&prime;}=w_k\underset{n=0}{\overset{15}{\mathrm{\&Sigma;}}}{a}_{4\mathrm{<figure-callout\; id="2"\; label="n\; e\; j"\; filenames="HPA00001390193200031.png,HPA00001390193200041.png"\; state="\{\{state\}\}">n</figure-callout>}}{e}^j{\frac{2\mathrm{\&pi;nk}}{16}}^{}---\left(10\right)$

In the case, the time shaft oscillogram s of STS _kand the correlation Rxx (l) having carried out between reception signal that window function processes according to formula (10) represents with formula (11).

[formula 11]

$\mathrm{Rxx}\left(l\right)=\underset{k=0}{\overset{63}{\mathrm{\&Sigma;}}}{s}_k^{\&prime;}{s^{*}}_{k+l}=\underset{k=0}{\overset{63}{\mathrm{\&Sigma;}}}{w}_k\underset{n=0}{\overset{15}{\mathrm{\&Sigma;}}}{a}_{4\mathrm{<figure-callout\; id="2"\; label="n\; e\; j"\; filenames="HPA00001390193200031.png,HPA00001390193200041.png"\; state="\{\{state\}\}">n</figure-callout>}}{e}^j{\frac{2\mathrm{\&pi;nk}}{16}}^{}\underset{m=0}{\overset{15}{\mathrm{\&Sigma;}}}{a_{4m}}^{*}{e}^{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HPA00001390193200031.png,HPA00001390193200041.png"\; state="\{\{state\}\}">j</figure-callout>}\frac{2\mathrm{\&pi;m}(k+l)}{16}}$

$=\underset{k=0}{\overset{63}{\mathrm{\&Sigma;}}}{w}_k\underset{n=0}{\overset{15}{\mathrm{\&Sigma;}}}\underset{m=0}{\overset{15}{\mathrm{\&Sigma;}}}{a}_{4n}{a^{*}}_{4m}{\mathrm{<figure-callout\; id="2"\; label="e\; j"\; filenames="HPA00001390193200031.png,HPA00001390193200041.png"\; state="\{\{state\}\}">e</figure-callout>}}^j{e}^{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HPA00001390193200031.png,HPA00001390193200041.png"\; state="\{\{state\}\}">j</figure-callout>}\frac{2\mathrm{\&pi;ml}}{16}}---\left(11\right)$

Herein, the ofdm signal that the hits that is FFT size due to imagination reception signal is 64, so window function w _kthere are 64 sampled points.In addition, the number of sampled point is 64, is even number, thereby window function w _kto take between the 31st sampling and the 32nd sampling as boundary is with respect to axisymmetric function of time.Therefore, w _k=w _63-kset up.

Fig. 5 (a) is the concept map during by the number of reception signal plus FFT size that does not carry out window function processing.Fig. 5 (b) is the concept map during by the number that has carried out the reception signal plus FFT size that window function processes.In addition, in Fig. 5 (a), (b), the each point in drawing represents to receive the sampled value of signal, and the longitudinal axis represents the imaginary axis, and transverse axis represents real axis.

As shown in Fig. 5 (a), the orthogonality based on ofdm signal, the reception signal that does not carry out window function processing is added after the number of FFT size, and aggregate value (summation) is 0.In addition, according to formula (10), the denominator of the index of exponential function is 16.In addition, receive 64 that the hits of the FFT size of signal is k=0～63.Therefore,, by receiving after the number of signal plus FFT size, as shown in Fig. 5 (a), receive signal the upper rotation of complex plane (complex plane) 4 weeks.

On the other hand, as shown in the stain of Fig. 5 (b), the reception signal that has carried out window function processing samples the 31st middle sample amplitudes from the 0th and becomes gradually greatly, with helical form, changes.And, as shown in the white point of Fig. 5 (b), with the 32nd of centre, being sampled as boundary and transferring to and reducing, amplitude diminishes gradually, with helical form, changes.

That is, carry out after window function processing, the imaginary number composition that receives signal has symmetry as shown in Fig. 5 (b), after the number of addition FFT size, cancels out each other, and aggregate value is almost 0, maintains orthogonality.The opposing party, real number composition does not have symmetry as shown in Fig. 5 (b), is therefore added after the number of FFT size, and aggregate value is not also 0, and orthogonality is destroyed.

Thus, receive signal and carried out after window function processing, orthogonality is destroyed, and between subcarrier, produces and disturbs, and in the OFDM symbol after demodulation, contains more error, cannot correctly carry out demodulation.

To this, in the present embodiment, carry out the window function shown in above-mentioned Fig. 4 (a), (b) and process.Below, specifically describing the window function shown in Fig. 4 (a), (b) processes.In the following description, at Fig. 4 (a), (b), suppose that the hits of base period is 64, p=31.Thus, at the window function w of Fig. 2 (a), (b) _kin, the hits of finite interval T1 is 2p+2=64.In addition, benchmark the 64th sampling that TR is i base period constantly.In addition, window function w _khits be even number 64, if thereby take sampled point PL as the 0th sampling, take sampled point PR as the 63rd sampling, window function w _kbecome that to take between the 31st sampling and the 32nd sampling be roughly symmetrical function of boundary.

First, as shown in Fig. 2 (a), (b), window function generating unit 21 is taken out window function w _ksampled point in the sampled point of the interval T11 of left-half generate left interval window function w _k, and establish left interval window function w _keach sampled point be w _k, based on 1-w _k, generate right interval window function 1-w _k.

[formula 12]

$s_k^{\&prime;}=\underset{n=0}{\overset{15}{\mathrm{\&Sigma;}}}{a}_{4\mathrm{<figure-callout\; id="2"\; label="n\; e\; j"\; filenames="HPA00001390193200031.png,HPA00001390193200041.png"\; state="\{\{state\}\}">n</figure-callout>}}{e}^j{\frac{2\mathrm{\&pi;nk}}{16}}^{}(k=-p~\mathrm{0,64}-p~64)---\left(12\right)$

Then,, as shown in formula (12), processing signals generating unit 22 is taken out the individual sampled point of p+1 (=32) of 0 sampling of the individual sampling to the of the-p (=-31) that receives signal.

Then,, as shown in formula (13), processing signals generating unit 22 is by left interval window function w _kthe 0th sampling to the p sampling p+1 sampled point be set as left interval window function w _kk=-p～0, make the left interval window function w setting _kact on and receive the-p sampling of signal to p+1 sampled point of the 0th sampling.

[formula 13]

$\underset{k=-p\&RightArrow;0}{s_k^{\&prime;}}=w_k\underset{n=0}{\overset{15}{\mathrm{\&Sigma;}}}{a}_{4\mathrm{<figure-callout\; id="2"\; label="n\; e\; j"\; filenames="HPA00001390193200031.png,HPA00001390193200041.png"\; state="\{\{state\}\}">n</figure-callout>}}{e}^j{\frac{2\mathrm{\&pi;nk}}{16}}^{}---\left(13\right)$

Then,, shown in (12), processing signals generating unit 22 is taken out the individual sampled point of p+1 (=32) of 64 samplings of the individual sampling to the of 64-p (=33) that receive signal.

Then,, as shown in formula (14), processing signals generating unit 22 is by right interval window function 1-w _kthe 0th sampling to the p sampling p+1 sampled point be set as right interval window function 1-w _kk=64-p～64, make the right interval window function 1-w setting _kact on and receive 64-p sampling of signal to p+1 sampled point of the 64th sampling.

[formula 14]

$\underset{k=64-p\&RightArrow;64}{s_k^{\&prime;}}=(1-w_k)\underset{n=0}{\overset{15}{\mathrm{\&Sigma;}}}{a}_{4\mathrm{<figure-callout\; id="2"\; label="n\; e\; j"\; filenames="HPA00001390193200031.png,HPA00001390193200041.png"\; state="\{\{state\}\}">n</figure-callout>}}{e}^j{\frac{2\mathrm{\&pi;nk}}{16}}^{}---\left(14\right)$

Then,, as shown in formula (15), efferent 23 is by the s ' of formula (13) _kthe s ' of (k=-p～0) and formula (14) _k(k=64-p～64) are added, as receiving the sampled point output of 64-p sampling of k=of signal to the 64th sampling.

[formula 15]

$\underset{k=-p\&RightArrow;0}{s_k^{\&prime;}}+\underset{k=64-p\&RightArrow;64}{s_k^{\&prime;}}$

$=w_k\underset{n=0}{\overset{15}{\mathrm{\&Sigma;}}}{a}_{4\mathrm{<figure-callout\; id="2"\; label="n\; e\; j"\; filenames="HPA00001390193200031.png,HPA00001390193200041.png"\; state="\{\{state\}\}">n</figure-callout>}}{e}^j{\frac{2\mathrm{\&pi;nk}}{16}}^{}+(1-w_k)\underset{n=0}{\overset{15}{\mathrm{\&Sigma;}}}{a}_{4\mathrm{<figure-callout\; id="2"\; label="n\; e\; j"\; filenames="HPA00001390193200031.png,HPA00001390193200041.png"\; state="\{\{state\}\}">n</figure-callout>}}{e}^j{\frac{2\mathrm{\&pi;nk}}{16}}^{}---\left(15\right)$

$=\underset{n=0}{\overset{15}{\mathrm{\&Sigma;}}}{a}_{4\mathrm{<figure-callout\; id="2"\; label="n\; e\; j"\; filenames="HPA00001390193200031.png,HPA00001390193200041.png"\; state="\{\{state\}\}">n</figure-callout>}}{e}^j{\frac{2\mathrm{\&pi;nk}}{16}}^{}$

The reception signal s ' obtaining based on formula (15) _kin, w _kdo not exist, so reception signal s ' of the number of FFT size _kas shown in Fig. 5 (a) with respect to initial point point symmetry be configured.Its result, processes by this window function, receives signal s ' _kcan maintain orthogonality.

, as the scope of k, considered the situation of k=-p～64 herein, but k=-p～16q (q is more than 1 integer value, p+1≤16q/2) (wherein, w _ksize be 2p+2) set up too.

As mentioned above, adopt above-mentioned window function to process, can maintain and receive signal s ' _korthogonality, can correctly take out OFDM symbol.

Then, consider s ' to received signal _kdisturbing wave am _kthe situation that the window function of applicable present embodiment is processed.In the following description, for convenience of explanation, only consider complementary sampled point k=-1,63.First, the hits of establishing FFT size is 64, to disturbing wave am _kcarry out Fourier expansion, disturbing wave is as formula (16) expression.

[formula 16]

${\mathrm{am}}_k={\mathrm{AM}}_{n_0}{e}^{j{\mathrm{\&Theta;}}_{n_0}}{\mathrm{<figure-callout\; id="2"\; label="e\; j"\; filenames="HPA00001390193200031.png,HPA00001390193200041.png"\; state="\{\{state\}\}">e</figure-callout>}}^j=\underset{n=0}{\overset{63}{\mathrm{\&Sigma;}}}{\mathrm{AM}}_n{e}^{j{\mathrm{\&Theta;}}_n}{e}^{\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HPA00001390193200031.png,HPA00001390193200041.png"\; state="\{\{state\}\}">j</figure-callout>}\frac{2\mathrm{\&pi;nk}}{64}}+{\mathrm{\&epsiv;}}_k---\left(16\right)$

Wherein, ε _krepresent to have carried out the disturbing wave of Fourier expansion and actual disturbing wave am _kbetween error.Make window function w _kact on k=-1, the disturbing wave am of 63 sampled point _kafter, obtain formula (17).

[formula 17]

$w_{-1}{\mathrm{am}}_{-1}=w_{-1}\underset{n=0}{\overset{63}{\mathrm{\&Sigma;}}}{\mathrm{AM}}_n{e}^{j{\mathrm{\&Theta;}}_n}{e}^{\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HPA00001390193200031.png,HPA00001390193200041.png"\; state="\{\{state\}\}">j</figure-callout>}\frac{2\mathrm{\&pi;n}(-1)}{64}}+w_{-1}{\mathrm{\&epsiv;}}_{-1}$

$=(1-w_{-1})\underset{n=0}{\overset{63}{\mathrm{\&Sigma;}}}{\mathrm{AM}}_n{e}^{j{\mathrm{\&Theta;}}_n}{e}^{\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HPA00001390193200031.png,HPA00001390193200041.png"\; state="\{\{state\}\}">j</figure-callout>}\frac{2\mathrm{\&pi;n}\left(63\right)}{64}}+(1-w_{-1}){\mathrm{\&epsiv;}}_{63}---\left(17\right)$

Above-mentioned w _-1am _-1and w ₆₃am ₆₃as shown in formula (18), be added.

[formula 18]

$w_{-1}{\mathrm{am}}_{-1}+w_{63}{\mathrm{am}}_{63}$

$=w_{-1}(\underset{n=0}{\overset{63}{\mathrm{\&Sigma;}}}{\mathrm{AM}}_n{e}^{j{\mathrm{\&Theta;}}_n}{e}^{\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HPA00001390193200031.png,HPA00001390193200041.png"\; state="\{\{state\}\}">j</figure-callout>}\frac{2\mathrm{\&pi;n}(-1)}{64}}+{\mathrm{\&epsiv;}}_{-1})$

$+(1-w_{-1})(\underset{n=0}{\overset{63}{\mathrm{\&Sigma;}}}{\mathrm{AM}}_n{e}^{j{\mathrm{\&Theta;}}_n}{e}^{\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HPA00001390193200031.png,HPA00001390193200041.png"\; state="\{\{state\}\}">j</figure-callout>}\frac{2\mathrm{\&pi;n}\left(63\right)}{64}}+{\mathrm{\&epsiv;}}_{63})---\left(18\right)$

As shown in formula (18), ε _-1-ε _-63item have a coefficient w _-1.Herein, w _-1meet 0 < w _-1≤ 1.Thus, based on above-mentioned window function, process, can make ε _-1-ε _-63impact be reduced to w _-1doubly, can suppress disturbing wave am _k.

In addition, as the k=-2 of other complementary sampled point, 62, k=-3,61, k=-4,60 ... also similarly represent with formula (18), can utilize window function w _ksuppress disturbing wave am _k.

As mentioned above, according to the receiving system of execution mode 1, reception signal s ' can not destroyed _kthe situation of orthogonality under suppress disturbing wave, detected symbol is regularly accurately.

In addition, in the above description, window function generating unit 21 is taken out the interval T11 of left-half, generates left interval window function w _k, but the invention is not restricted to this.That is, window function generating unit 21 also can be taken out window function w _kthe interval T12 of right half part generate right interval window function w _k, and based on this right interval window function w _k, generate left interval window function 1-w _k.

And as shown in Fig. 2 (a), (b), window function generating unit 21 is taken out p+1 the sampled point of the interval T12 of right half part, generates right interval window function w _k.And the value of establishing each sampled point of right interval window function is w _k, based on 1-w _k, generate left interval window function 1-w _k.In the case, right interval window function w _k, left interval window function 1-w _kfinite interval be the interval T12 of right half part.

In addition, in the above description, first to generate, generate the second processing signals after the first processing signals S1 and be illustrated, but be not limited to this, generate the first processing signals after also can first generating the second processing signals S2.These modes are also applicable in following execution mode.

(execution mode 2)

The receiving system of embodiment of the present invention 2 take arrange base period respectively different a plurality of window function handling parts 2 be feature.In addition, in the present embodiment, the description thereof will be omitted for the part identical with execution mode 1.

Fig. 6 represents the block diagram of the receiving system of embodiment of the present invention 2.As shown in Figure 6, receiving system comprises three window function handling parts 201 to 203.

The hits of the base period of window function handling part 201 and window function w _kthe hits of finite interval T1 be STS 3 times 64.The hits of the base period of window function handling part 202 and window function w _kthe hits of finite interval T1 be STS 2 times 32.The hits of the base period of window function handling part 203 and window function w _kthe hits of finite interval T1 be STS 1 times 16.In addition, the processing details of window function handling part 201 to 203 is identical with the window function handling part 2 of execution mode 1, and therefore description thereof is omitted.

Regularly test section 3 was obtained from the cycle of the correlation peak that respectively receives signal of window function handling part 201 to 203 outputs, and the cycle based on correlation peak, close to the correlation peak of the reception signal in cycle of STS, is detected the Symbol Timing of multi-carrier signal.

Particularly, regularly test section 3 comprises three correlators 311 to 313, peak value test section 321 to 323 and the peak counter 351 to 353 corresponding with window function handling part 201 to 203.In addition, regularly test section 3 comprises threshold value storage part 33 and timing detection unit 34.

Correlator 311 to 313 calculates respectively from the reception signal of window function handling part 201 to 203 outputs and the correlation between the time shaft oscillogram of STS, and is output in peak value test section 321 to 323.

Peak value test section 321 to 323 detects respectively from the correlation peak of the correlation of correlator 311 to 313 outputs.In addition, the detection method of the correlation peak of peak value test section 321 to 323 is identical with the peak value test section 32 of execution mode 1, therefore omits detailed explanation.

Peak counter 351 to 353 is counted the hits of the peak intervals of peak value test section 321 to 323 detected correlation peaks respectively.

Regularly detection unit 34 is in the situation that any in peak counter 351 to 353 detects the peak intervals of 16 samplings of the one-period that is equivalent to STS, using this peak counter as gazing at peak counter, and will be set as valid interval from for example interval of 32 samplings with this detection constantly of initial correlation peak of gazing at the corresponding correlator of peak counter (should be peak value test section).

And, regularly detection unit 34 is in this valid interval, when gazing at peak counter can repeatedly count the peak intervals of 16 samplings time, using with this gaze at the corresponding correlator of peak counter initial correlation peak detection out as symbol timing detection constantly.In addition, although gaze at the count value of the peak intervals of peak counter, be not 16, regularly detection unit 34 also can be, for example, while being positioned in 16 ± 1 scope, peak intervals is judged to be effectively.

Fig. 7 (a) means the figure of result of calculation of the correlation of correlator to (d), (a) represent not carrying out the reception signal of window function processing, correlation while getting the phase cross-correlation with the time shaft oscillogram of STS, (b) to (d) correlation of correlator 311 to 313 calculating shown in presentation graphs 6 respectively.In addition, at Fig. 7 (a), in (d), the longitudinal axis represents correlation, and transverse axis represents the time with hits.In addition, at Fig. 7 (a), in (d), threshold value represents above-mentioned threshold value b.

In Fig. 7 (a), from detecting at first correlation peak, to play the peak intervals then detecting till correlation peak be not 16 samplings, therefore cannot detect Symbol Timing.

In Fig. 7 (b), from peak value test section 321 detects correlation peak at first to the hits detecting till next correlation peak be 16, therefore set the valid interval of 32 samplings from the detection constantly of initial correlation peak.And, in this valid interval, twice repeatedly of the peak intervals of 16 samplings.Therefore the moment that, regularly detection unit 34 detects correlation peak at first using correlator 311 (should be peak value test section 321) as symbol timing detection out.That is, the detection of Symbol Timing success.

In Fig. 7 (c), the same with Fig. 7 (a), cannot detect Symbol Timing.In Fig. 7 (d), the same with Fig. 7 (b), the detection success of Symbol Timing.

In above-mentioned formula (18), if ε _-63+ w _-1(ε _-1-ε _-63)=0, the effect that window function is processed reaches maximum, can suppress disturbing wave am _k.For this formula is set up, ε _-1and ε _-63need to meet formula (19).

[formula 19]

${\mathrm{\&epsiv;}}_{63}\&GreaterEqual;0,{\mathrm{\&epsiv;}}_{-1}-{\mathrm{\&epsiv;}}_{63}\&le;0\&DoubleLeftRightArrow;{\mathrm{\&epsiv;}}_{63}\&GreaterEqual;0,{\mathrm{\&epsiv;}}_{-1}\&le;0$

${\mathrm{\&epsiv;}}_{63}\&le;0,{\mathrm{\&epsiv;}}_{-1}-{\mathrm{\&epsiv;}}_{63}\&GreaterEqual;0\&DoubleLeftRightArrow;{\mathrm{\&epsiv;}}_{63}\&le;0,{\mathrm{\&epsiv;}}_{-1}\&GreaterEqual;0---\left(19\right)$

But, ε _kdepend on disturbing wave am _kphase place and frequency, so the relation of formula (19) is not necessarily set up.To this, in execution mode 2, different three the window function handling parts 201 to 203 of base period are set respectively.Accordingly, any the peak value test section in peak value test section 321 to 323 can detect correlation peak accurately, and detected symbol regularly, can improve the effect that window function is processed more reliably.

(execution mode 3)

Compare with the receiving system of execution mode 2, the receiving system of execution mode 3 take that two known symbol storage parts are set is feature.Fig. 8 represents the block diagram of the receiving system of execution mode 3.

Known symbol storage part 41,42 is stored respectively by combination and is used for a plurality of subcarriers of generation of STS and the different multiple time shaft oscillogram of frequency band that generates in advance.In IEEE802.11a, use the time shaft oscillogram of 12 subcarriers generation STS in 64 subcarriers.

Fig. 9 (a) to (c) represents the power spectrum for the subcarrier of the time shaft waveform map generalization of STS.Fig. 9 (a) represents the subcarrier of the time shaft waveform map generalization for STS in the past, Fig. 9 (b) represents the subcarrier of the time shaft waveform map generalization for STS of known symbol storage part 41 storages, and Fig. 9 (c) represents the subcarrier of the time shaft waveform map generalization for STS of known symbol storage part 42 storages.

As shown in Fig. 9 (a), the time shaft oscillogram of STS is in the past used 12 subcarriers to generate.Therefore,, in the situation that be loaded with disturbing wave in the frequency band of any subcarrier in 12 subcarriers, cannot detect accurately Symbol Timing.

To this, as shown in Fig. 9 (b), the time shaft oscillogram of 3 and the STS that 3 subcarriers that amount to 6 two ends frequency bands generate from the right from the left side of 12 subcarriers of pre-stored use Fig. 9 of known symbol storage part 41 (a).In addition, as shown in Fig. 9 (c), the time shaft oscillogram of the STS that the 4th to the 9th subcarrier that amounts to 6 intermediate frequency band from the left side of 12 subcarriers of pre-stored use Fig. 9 of known symbol storage part 42 (a) generates.

Turn back to Fig. 8, correlator 311 to 313 is obtained respectively from the reception signal of window function handling part 201 to 203 outputs and known symbol storage part 41 correlation between the time shaft oscillogram of STS of storage.

Correlator 314 to 316 is obtained respectively from the reception signal of window function handling part 201 to 203 outputs and known symbol storage part 42 correlation between the time shaft oscillogram of STS of storage.

Peak value test section 321 to 323 detects respectively from the correlation peak of the correlation of correlator 311 to 313 outputs.In addition, peak value test section 324 to 326 detects respectively from the correlation peak of the correlation of correlator 314 to 316 outputs.In addition, the detection method of the correlation peak of peak value test section 321 to 326 is identical with the peak value test section 32 of execution mode 1, therefore omits detailed explanation.

Peak counter 351 to 356 is counted the hits of the peak intervals of peak value test section 321 to 323 detected correlation peaks respectively.

Regularly detection unit 34, respectively according to the peak intervals of peak counter 351 to 356 countings, is used the method detected symbol identical with execution mode 2 regularly.That is, regularly detection unit 34 based on according to the peak period of the correlation peak of peak counter 351 to 356 countings close to the time shaft oscillogram and the correlation peak receiving between signal in cycle of STS, the Symbol Timing of detection multi-carrier signal.

Each output threshold value a and threshold value b in 33 pairs of peak value test sections 321 to 326 of threshold value storage part.

Then, use numerical expression to describe the processing of the correlator 311 to 316 of present embodiment.First, suppose by the window function of window function handling part 201 to 203 and process, disturbing wave am _kin error ε _kbe decreased to negligible degree, can as shown in formula (20), be similar to.

[formula 20]

${\mathrm{am}}_k={\mathrm{AM}}_{n_0}{e}^{j{\mathrm{\&Theta;}}_{n_0}}{\mathrm{<figure-callout\; id="2"\; label="e\; j"\; filenames="HPA00001390193200031.png,HPA00001390193200041.png"\; state="\{\{state\}\}">e</figure-callout>}}^j\&ap;\underset{n=0}{\overset{63}{\mathrm{\&Sigma;}}}{\mathrm{AM}}_n{e}^{j{\mathrm{\&Theta;}}_n}{e}^{\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HPA00001390193200031.png,HPA00001390193200041.png"\; state="\{\{state\}\}">j</figure-callout>}\frac{2\mathrm{\&pi;nk}}{64}}---\left(20\right)$

Suppose disturbing wave am herein, _kthe low territory side that is present in the above-mentioned two ends frequency band of n=0～15, the disturbing wave am of n=16～63 _kcan ignore.In the case, disturbing wave am _kcan be similar to by enough formula (21).

[formula 21]

${\mathrm{am}}_k\&ap;\underset{n=0}{\overset{63}{\mathrm{\&Sigma;}}}{\mathrm{AM}}_n{e}^{j{\mathrm{\&Theta;}}_n}{e}^{\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HPA00001390193200031.png,HPA00001390193200041.png"\; state="\{\{state\}\}">j</figure-callout>}\frac{2\mathrm{\&pi;n}\left(63\right)}{64}}\&ap;\underset{n=0}{\overset{15}{\mathrm{\&Sigma;}}}{\mathrm{AM}}_n{e}^{j{\mathrm{\&Theta;}}_n}{e}^{\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HPA00001390193200031.png,HPA00001390193200041.png"\; state="\{\{state\}\}">j</figure-callout>}\frac{2\mathrm{\&pi;nk}}{64}}---\left(21\right)$

In addition, the time shaft of the STS of known symbol storage part 41 storages formula (22) expression for oscillogram.Wherein, the sampling interval of m is 4 times of sampling interval of n.

[formula 22]

$\underset{m=4}{\overset{11}{\mathrm{\&Sigma;}}}{a^{*}}_{4m}{e}^{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HPA00001390193200031.png,HPA00001390193200041.png"\; state="\{\{state\}\}">j</figure-callout>}\frac{2\mathrm{\&pi;m}(k+l)}{16}}---\left(22\right)$

On the other hand, the time shaft of the STS of known symbol storage part 42 storages formula (23) expression for oscillogram.

[formula 23]

$\underset{m=0}{\overset{3}{\mathrm{\&Sigma;}}}{a^{*}}_{4m}{e}^{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HPA00001390193200031.png,HPA00001390193200041.png"\; state="\{\{state\}\}">j</figure-callout>}\frac{2\mathrm{\&pi;m}(k+l)}{16}}+\underset{m=12}{\overset{15}{\mathrm{\&Sigma;}}}{a^{*}}_{4m}{e}^{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HPA00001390193200031.png,HPA00001390193200041.png"\; state="\{\{state\}\}">j</figure-callout>}\frac{2\mathrm{\&pi;m}(k+l)}{16}}---\left(23\right)$

Be not loaded with disturbing wave am _kformula (22) STS time shaft oscillogram with comprise disturbing wave am _kreception signal s ' _k+ am _kbetween correlation Rxx (l) with formula (24), represent.In addition,, owing to supposing that disturbing wave is loaded in the low territory side of the two ends frequency band of n=0～15, in n=16～63, place is not loaded with disturbing wave, so the s ' shown in the first row of formula (24) _k+ am _kin n=16～63 o'clock, am _k=0.Therefore,, in formula (24), save the calculating of n=16～63.

[formula 24]

$\mathrm{Rxx}\left(l\right)=\underset{k=0}{\overset{63}{\mathrm{\&Sigma;}}}(s_k^{\&prime;}+{\mathrm{am}}_k){s^{*}}_{k+l}$

$=\underset{k=0}{\overset{63}{\mathrm{\&Sigma;}}}\{\underset{n=0}{\overset{15}{\mathrm{\&Sigma;}}}{H}_{4n}{e}^{j{\mathrm{\&theta;}}_{4n}}{a}_{4\mathrm{<figure-callout\; id="2"\; label="n\; e\; j"\; filenames="HPA00001390193200031.png,HPA00001390193200041.png"\; state="\{\{state\}\}">n</figure-callout>}}{e}^j{\frac{2\mathrm{\&pi;nk}}{16}}^{}\underset{m=0}{\overset{15}{\mathrm{\&Sigma;}}}{a^{*}}_{4m}{e}^{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HPA00001390193200031.png,HPA00001390193200041.png"\; state="\{\{state\}\}">j</figure-callout>}\frac{2\mathrm{\&pi;m}(k+l)}{16}}$

$+\underset{n=0}{\overset{15}{\mathrm{\&Sigma;}}}A{M}_n{e}^{j{\mathrm{\&Theta;}}_n}{e}^{\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HPA00001390193200031.png,HPA00001390193200041.png"\; state="\{\{state\}\}">j</figure-callout>}\frac{2\mathrm{\&pi;}\mathrm{<figure-callout\; id="64"\; label="n\; k"\; filenames="HPA00001390193200041.png"\; state="\{\{state\}\}">n</figure-callout>}k}{64}}\underset{m=4}{\overset{11}{\mathrm{\&Sigma;}}}{a^{*}}_{4m}{e}^{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HPA00001390193200031.png,HPA00001390193200041.png"\; state="\{\{state\}\}">j</figure-callout>}\frac{2\mathrm{\&pi;m}(k+l)}{16}}\}$

$=\underset{k=0}{\overset{63}{\mathrm{\&Sigma;}}}\{\underset{n=0}{\overset{15}{\mathrm{\&Sigma;}}}\underset{m=4}{\overset{11}{\mathrm{\&Sigma;}}}{H}_{4n}{e}^{j{\mathrm{\&theta;}}_{4n}}{a}_{4\mathrm{<figure-callout\; id="2"\; label="n\; e\; j"\; filenames="HPA00001390193200031.png,HPA00001390193200041.png"\; state="\{\{state\}\}">n</figure-callout>}}{e}^j{\frac{2\mathrm{\&pi;nk}}{16}}^{}{a^{*}}_{4m}{e}^{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HPA00001390193200031.png,HPA00001390193200041.png"\; state="\{\{state\}\}">j</figure-callout>}\frac{2\mathrm{\&pi;m}(k+l)}{16}}$

$+\underset{n=0}{\overset{15}{\mathrm{\&Sigma;}}}\underset{m=4}{\overset{11}{\mathrm{\&Sigma;}}}{\mathrm{AM}}_n{e}^{j{\mathrm{\&Theta;}}_n}{e}^{\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HPA00001390193200031.png,HPA00001390193200041.png"\; state="\{\{state\}\}">j</figure-callout>}\frac{2\mathrm{\&pi;nk}}{64}}{a^{*}}_{4m}{e}^{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HPA00001390193200031.png,HPA00001390193200041.png"\; state="\{\{state\}\}">j</figure-callout>}\frac{2\mathrm{\&pi;m}(k+l)}{16}}\}$

$=\underset{k=0}{\overset{63}{\mathrm{\&Sigma;}}}\{\underset{n=0}{\overset{15}{\mathrm{\&Sigma;}}}\underset{m=4}{\overset{11}{\mathrm{\&Sigma;}}}{H}_{4n}{e}^{j{\mathrm{\&theta;}}_{4n}}{a}_{4n}{a^{*}}_{4m}{\mathrm{<figure-callout\; id="2"\; label="e\; j"\; filenames="HPA00001390193200031.png,HPA00001390193200041.png"\; state="\{\{state\}\}">e</figure-callout>}}^j{e}^{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HPA00001390193200031.png,HPA00001390193200041.png"\; state="\{\{state\}\}">j</figure-callout>}\frac{2\mathrm{\&pi;ml}}{16}}$

$+\underset{n=0}{\overset{15}{\mathrm{\&Sigma;}}}\underset{m=4}{\overset{11}{\mathrm{\&Sigma;}}}{\mathrm{AM}}_n{e}^{j{\mathrm{\&Theta;}}_n}{e}^{\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HPA00001390193200031.png,HPA00001390193200041.png"\; state="\{\{state\}\}">j</figure-callout>}\frac{2\mathrm{\&pi;nk}}{64}}{a^{*}}_{4m}{e}^{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HPA00001390193200031.png,HPA00001390193200041.png"\; state="\{\{state\}\}">j</figure-callout>}\frac{2\mathrm{\&pi;m}(k+l)}{16}}\}$

$=\underset{n=4}{\overset{11}{\mathrm{\&Sigma;}}}{H}_{4n}{e}^{j{\mathrm{\&theta;}}_{4n}}{\left|a_{4n}\right|}^2{e}^{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HPA00001390193200031.png,HPA00001390193200041.png"\; state="\{\{state\}\}">j</figure-callout>}\frac{2\mathrm{\&pi;nl}}{16}}+\underset{n=0}{\overset{15}{\mathrm{\&Sigma;}}}\underset{m=4}{\overset{11}{\mathrm{\&Sigma;}}}{\mathrm{AM}}_n{e}^{j{\mathrm{\&Theta;}}_n}{a^{*}}_{2m}{\mathrm{<figure-callout\; id="2"\; label="e\; j"\; filenames="HPA00001390193200031.png,HPA00001390193200041.png"\; state="\{\{state\}\}">e</figure-callout>}}^j{e}^{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HPA00001390193200031.png,HPA00001390193200041.png"\; state="\{\{state\}\}">j</figure-callout>}\frac{2\mathrm{\&pi;}2\mathrm{<figure-callout\; id="64"\; label="ml"\; filenames="HPA00001390193200041.png"\; state="\{\{state\}\}">ml</figure-callout>}}{64}}$

$=\underset{n=4}{\overset{11}{\mathrm{\&Sigma;}}}{H}_{4n}{e}^{j{\mathrm{\&theta;}}_{2n}}{\left|a_{4n}\right|}^2{e}^{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HPA00001390193200031.png,HPA00001390193200041.png"\; state="\{\{state\}\}">j</figure-callout>}\frac{2\mathrm{\&pi;nl}}{16}}---\left(24\right)$

Herein, in second of the row second from the bottom of formula (24), n=0～15,, there is not the condition that meets n=4m in m=4～11, is therefore 0.

Therefore, at disturbing wave am _kbe loaded in the situation of low territory side of two ends frequency band of n=0～15, because the time shaft oscillogram of the STS of known symbol storage part 42 storage is the time shaft oscillogram of intermediate frequency band, if so use this time shaft oscillogram to carry out relevant treatment, can make disturbing wave am _kbe 0.Thus, the correlator 314 to 316 shown in Fig. 8 is compared with correlator 311 to 313, can obtain accurately correlation.

On the other hand, at disturbing wave am _kbe loaded in the situation of intermediate frequency band of n=15～48, because the time shaft oscillogram of the STS of known symbol storage part 41 storage is the time shaft oscillogram of two ends frequency band, so use this time shaft oscillogram to carry out the correlator 311 to 313 shown in Fig. 8 of relevant treatment, compare with correlator 314 to 316, can obtain accurately correlation.

Figure 10 has represented to superpose and take the correlated results of reception signal of the disturbing wave that is carried out AM modulation that 3.4MHz is carrier wave.In addition, Figure 11 has represented to superpose and take the correlated results of signal vector of the disturbing wave that is carried out AM modulation that 20.2MHz is carrier wave.

In Figure 10 and Figure 11, first row represents to use the correlated results in the situation of time shaft oscillogram of the STS that the subcarrier based on Fig. 9 (a) generates, secondary series represents to use the correlated results in the situation of time shaft oscillogram of the STS that the subcarrier (subcarrier of intermediate frequency band) based on Fig. 9 (c) generates, and the correlated results in the situation of time shaft oscillogram of the STS that the subcarrier (subcarrier of two ends frequency band) that uses based on Fig. 9 (b) generates is shown in the 3rd list.

In addition, in Figure 10 and Figure 11, the first row represents not carry out the correlated results in the situation of window function processing, and the 2nd to 4 row represent that respectively the hits of base period is the correlated results in 64,32,16 situation.

That is, in Figure 10 and Figure 11, the correlated results of the 2nd to 4 row of secondary series is the correlated results of the correlator 314 to 316 shown in presentation graphs 8 respectively, and the correlated results of tertial the 2nd to 4 row is the correlated results of the correlator 311 to 313 shown in presentation graphs 8 respectively.

In Figure 10, interference wave frequency is 3.4MHz, because the frequency band of disturbing wave belongs to the low territory side of the two ends frequency band of n=0～15, therefore known, in the 2nd to 4 row of the secondary series surrounding with quadrilateral frame, obtain good correlated results, the detection success of Symbol Timing.

In Figure 11, interference wave frequency is 20.2MHz, and the frequency band of disturbing wave belongs to the intermediate frequency band of n=16～48, therefore known, in tertial the 2nd to 4 row that surround with quadrangle, obtains good correlated results, the detection success of Symbol Timing.

As mentioned above, according to the receiving system of present embodiment, for the hits that utilizes base period respectively different three window functions carried out the reception signal that window function is processed, obtain the correlation of the time shaft oscillogram of STS of intermediate frequency band and the time shaft oscillogram of the STS of two ends frequency band, in these correlations, use can precision the correlation values detection Symbol Timing at detection peak interval best, therefore can precision detect higher Symbol Timing.

In addition,, in execution mode 3, the time shaft oscillogram of STS has adopted two kinds, but also can adopt more than three kinds.In the case, the different subcarrier rise time axle oscillogram of combination frequency just can respectively.

In addition, in execution mode 2,3, window function handling part has adopted three kinds, but is not limited to this, also can adopt more than four kinds.In the case, the different value of the integral multiple of the one-period of the base period of each window function handling part employing STS just can.

The technical characterictic of above-mentioned receiving system can be summarized as follows.

(1) receiving system involved in the present invention detects the Symbol Timing of the multi-carrier signal of the front pilot that comprises known symbol repetition, comprise: window function handling part, utilization has the window function of the finite interval shorter than the base period of the integral multiple in the cycle of described known symbol, carries out to received signal window function processing; And timing test section, obtain described window function handling part and carry out the correlation peak between the reception signal of window function processing and the time shaft oscillogram of described known symbol, based on this correlation peak, detect the Symbol Timing of described multi-carrier signal, wherein, described window function handling part comprises: window function generating unit, the left-half interval or the right half part that take out described window function are interval, window function based on taking out, generates as the left interval window function of the window function in described left-half interval with as the right interval window function of the window function in described right half part interval; Processing signals generating unit, using moment of reception signal of finite interval of recalling the moment of described base period from the benchmark of appointment constantly and recalling described left interval window function again as starting point, described left interval window function is generated to the first processing signals with described reception signal multiplication chronologically, and using moment of the described reception signal of recalling described right half part interval from described benchmark constantly as starting point, described right interval window function is generated to the second processing signals with described reception signal multiplication chronologically; And efferent, the reception signal of the signal that described the first processing signals and described the second processing signals are added chronologically till as date back the finite interval of described right interval window function constantly from described benchmark, exports described timing test section to.

In addition, method for detecting symbol timing involved in the present invention detects the Symbol Timing of the multi-carrier signal of the front pilot that comprises known symbol repetition, comprise the following steps: window function treatment step, utilizes the window function with the finite interval shorter than the base period of the integral multiple in the cycle of described known symbol to carry out to received signal window function processing; And timing detecting step, obtain the reception signal processed by described window function treatment step and the correlation peak between the time shaft oscillogram of described known symbol, and the Symbol Timing based on multi-carrier signal described in this correlation peak detection, wherein, described window function treatment step comprises the following steps: window function generates step, the left-half interval or the right half part that take out described window function are interval, and the window function based on taking out generates left interval window function and right interval window function; Processing signals generates step, using moment of reception signal of finite interval of recalling the moment of described base period from the benchmark of appointment constantly and recalling described left interval window function again as starting point, described left interval window function is generated to the first processing signals with described reception signal multiplication chronologically, and using from described benchmark, constantly recall described right interval window function moment of described reception signal of finite interval as starting point, described right interval window function is generated to the second processing signals with described reception signal multiplication chronologically; And output step, the signal that described the first processing signals and described the second processing signals are added chronologically, as the reception signal date back constantly the finite interval of described right interval window function from described benchmark till and export.

According to these structures, take out the left-half of window function or the interval of right half part, the window function based on taking out, generates left interval window function and right interval window function.And, the benchmark from appointment is recalled to the moment of base period constantly, and moment of reception signal of finite interval of recalling again left interval window function as starting point, by left interval window function chronologically with receive signal multiplication, generate the first processing signals.In addition, using moment of reception signal of finite interval of constantly recalling right interval window function from benchmark as starting point, by right interval window function chronologically with receive signal multiplication, generate the second processing signals.

And the signal that the first processing signals and described the second processing signals are added chronologically, exports as the reception signal date back constantly the finite interval of right interval window function from benchmark till.

Accordingly, can when maintaining the orthogonality that receives signal, suppress to receive the disturbing wave comprising in signal, therefore detected symbol timing accurately.

(2) comparatively it is desirable to, described window function generating unit is taken out the window function in described left-half interval, and generates the window function of taking-up as described left interval window function, by deducting described left interval window function from 1, generates described right interval window function.

According to this structure, take out the window function in left-half interval, using the window function of taking-up as left interval window function, generate, and based on the left interval window function of 1-, generate right interval window function.Therefore, can generate left interval window function and the right interval window function that finite interval equates by simple processing.

(3) comparatively it is desirable to, described window function generating unit is taken out the window function in described right half part interval, and generates the window function of taking-up as described right interval window function, by deducting described right interval window function from 1, generates described left interval window function.

According to this structure, take out the window function in right half part interval, using the window function of taking-up as right interval window function, generate, and based on the right interval window function of 1-, generate left interval window function.Therefore, can generate left interval window function and the right interval window function that finite interval equates by simple processing.

(4) comparatively it is desirable to, described window function handling part exists a plurality of, the described base period of each window function handling part is different, described timing test section is obtained from the peak period of the correlation peak that respectively receives signal of each window function handling part output, based on described peak period, close to the correlation peak of the reception signal in cycle of described known symbol, detect the Symbol Timing of described multi-carrier signal.

According to this structure, the different window function handling part of a plurality of base periods difference is set.Therefore, can utilize from suppressing to disturb the reception input Symbol Timing of the window function handling part output of intensity of wave, can precision detected symbol is regularly higher.

(5) comparatively it is desirable to, also comprise known symbol storage part, storage by combination, be used for a plurality of subcarriers of generation of described known symbol and generation in advance, multiple time shaft oscillogram that frequency band is different, wherein, described timing test section is obtained from the reception signal of described window function handling part output and the peak period of the correlation peak between each time shaft oscillogram, based on described peak period, close to the time shaft oscillogram in cycle of described known symbol and the correlation peak between described reception signal, detect the Symbol Timing of described multi-carrier signal.

According to this structure, service band respectively a plurality of time shaft oscillograms of different known symbols is obtained correlation peak.Therefore, can use the time shaft oscillogram of the frequency band that is not loaded with disturbing wave to obtain correlation peak, utilize with the correlation peak that this time shaft oscillogram is obtained and come detected symbol regularly, thus can precision detected symbol timing higher.

(6) comparatively it is desirable to, described timing test section is usingd interior correlation as correlation peak detection out by the scope of appointment, and utilizes this correlation peak to obtain described peak period.

According to this structure, will using interior correlation as correlation peak detection out in the scope of appointment, and use this correlation peak to obtain peak period, therefore detected symbol timing accurately.

Claims (7)

1. a receiving system, detects the Symbol Timing of the multi-carrier signal that comprises the front pilot that known symbol repeats, and it is characterized in that comprising:

Window function handling part, utilizes the window function with the finite interval shorter than the base period of the integral multiple in the cycle of described known symbol, carries out to received signal window function processing; And

Regularly test section, obtains described window function handling part and carries out the correlation peak between the reception signal of window function processing and the time shaft oscillogram of described known symbol, based on this correlation peak, detects the Symbol Timing of described multi-carrier signal, wherein,

Described window function handling part comprises:

Window function generating unit, the left-half interval or the right half part that take out described window function are interval, and the window function based on taking out, generates left interval window function and right interval window function;

Processing signals generating unit, using moment of reception signal of finite interval of recalling the moment of described base period from the benchmark of appointment constantly and recalling described left interval window function again as starting point, described left interval window function is generated to the first processing signals with described reception signal multiplication chronologically, and using moment of described reception signal of the finite interval of recalling described right interval window function from described benchmark constantly as starting point, described right interval window function is generated to the second processing signals with described reception signal multiplication chronologically; And

Efferent, the reception signal of the signal that described the first processing signals and described the second processing signals are added chronologically till as date back the finite interval of described right interval window function constantly from described benchmark, exports described timing test section to.

2. receiving system according to claim 1, is characterized in that:

Described window function generating unit is taken out the window function in described left-half interval, and generates the window function of taking-up as described left interval window function, by deducting described left interval window function from 1, generates described right interval window function.

3. receiving system according to claim 1, is characterized in that:

Described window function generating unit is taken out the window function in described right half part interval, and generates the window function of taking-up as described right interval window function, by deducting described right interval window function from 1, generates described left interval window function.

4. according to the receiving system described in any one in claims 1 to 3, it is characterized in that:

Described window function handling part exists a plurality of,

The described base period of each window function handling part is different,

Described timing test section is obtained from the peak period of the correlation peak that respectively receives signal of each window function handling part output, based on described peak period, close to the correlation peak of the reception signal in cycle of described known symbol, detect the Symbol Timing of described multi-carrier signal.

5. according to the receiving system described in any one in claims 1 to 3, characterized by further comprising:

Known symbol storage part, storage by combination, be used for a plurality of subcarriers of generation of described known symbol and generation in advance, multiple time shaft oscillogram that frequency band is different, wherein,

Described timing test section is obtained from the reception signal of described window function handling part output and the peak period of the correlation peak between each time shaft oscillogram, based on described peak period, close to the time shaft oscillogram in cycle of described known symbol and the correlation peak between described reception signal, detect the Symbol Timing of described multi-carrier signal.

6. according to the receiving system described in any one in claims 1 to 3, it is characterized in that:

Described timing test section is usingd interior correlation as correlation peak detection out by the scope of appointment, and utilizes this correlation peak to obtain described peak period.

7. a method for detecting symbol timing, detects the Symbol Timing of the multi-carrier signal that comprises the front pilot that known symbol repeats, and it is characterized in that comprising the following steps:

Window function treatment step, utilizes the window function with the finite interval shorter than the base period of the integral multiple in the cycle of described known symbol to carry out to received signal window function processing; And

Detecting step regularly, obtains the reception signal processed by described window function treatment step and the correlation peak between the time shaft oscillogram of described known symbol, and the Symbol Timing based on multi-carrier signal described in this correlation peak detection, wherein,

Described window function treatment step comprises the following steps:

Window function generates step, and the left-half interval or the right half part that take out described window function are interval, and the window function based on taking out generates left interval window function and right interval window function;

Processing signals generates step, using moment of reception signal of finite interval of recalling the moment of described base period from the benchmark of appointment constantly and recalling described left interval window function again as starting point, described left interval window function is generated to the first processing signals with described reception signal multiplication chronologically, and using from described benchmark, constantly recall described right interval window function moment of described reception signal of finite interval as starting point, described right interval window function is generated to the second processing signals with described reception signal multiplication chronologically; And

Output step, the signal that described the first processing signals and described the second processing signals are added chronologically, exports as the reception signal date back constantly the finite interval of described right interval window function from described benchmark till.

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