CN1571311A - Apparatus and method for symbol border detecting - Google Patents

Apparatus and method for symbol border detecting Download PDF

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Publication number
CN1571311A
CN1571311A CNA03150129XA CN03150129A CN1571311A CN 1571311 A CN1571311 A CN 1571311A CN A03150129X A CNA03150129X A CN A03150129XA CN 03150129 A CN03150129 A CN 03150129A CN 1571311 A CN1571311 A CN 1571311A
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signal
sampled
sampled signal
peak
estimating
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柳德政
刘泰诚
汤松年
颜光裕
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Realtek Semiconductor Corp
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Realtek Semiconductor Corp
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Abstract

The invention discloses a symbol boundary detecting device and method, used in the receiver of communication system, using a critical value to aid judgment so as to select proper symbol boundary reference point in the initial range. The critical value can be flexibly set according to different system properties. In addition, it further uses a pilot frequency symbol protecting interval matching filter to judge if it receives a protecting interval of the pilot frequency symbol.

Description

The symbol boundary detection device and method
Technical field
The present invention relates to a kind of symbol boundary detection device and method of communication system, particularly a kind of auxiliary by critical value chosen the symbol boundary detection device and method of suitable border reference point.
Background technology
In recent years, multicarrier (multi-carrier or multi-tone) system has been widely used in transfer of data, as be applied to IEEE 802.11a/g WLAN (wireless local area network, WLAN) Orthodoxy Frequency Division Multiplex (orthogonal frequency division multiplexing, OFDM) technology.Fig. 1 is the block diagram of a typical ofdm system.This ofdm system 100 is N subchannels that the data that will transmit placed frequency domain by signal map (signal mapping) device 101 respectively in transmitter.Then; utilize invert fast fourier transformation (inverse fast Fourier transform; IFFT) device 102 converts time-domain signal to; add protection (guard interval at interval; GI) after, through serialiser (parallel-to-serial converter, P/S) 104 and digital to analog converter (digital-to-analog converter; DAC) 105, transmit via channel 106 again.Receiver is then earlier through analog to digital converter (analog-to-digital converter, ADC) after 107 samplings, GI is removed, and through serial parallel converters (serial-to-parallel converter, S/P) 110, send into fast fourier transform (fast Fourier transform again, FFT) device 11 1 is changed back frequency-region signal, in each subchannel, carry out channel compensation (channel compensation) respectively, separate mapping (signal demapping) device 113 by signal at last and demodulate former transmission data.
We are called symbol (symbol) with the output valve of one group of N point IFFT.And because channel impulse response (channel impulse response, CIR) all imperfect usually, can cause a symbol through behind the channel 106, have influence on the reception of successive character in receiver, cause intersymbol interference (inter-symbolinterference, ISI).For avoiding this problem, generally can be at the extra segment protect (GI) at interval that adds of intersymbol.Generally speaking, GI be with Cyclic Prefix (Cyclic Prefix, mode CP) adds; That is the signal that duplicates the output symbol back segment is used as GI in leading portion.Thus, be no more than in channel impulse response length under the situation of GI, can avoid the generation of ISI, N subchannel do not disturbed independently of one another mutually.The signal processing of this part is by the circuit 103 that increases the protection interval among Fig. 1 and remove protection circuit 109 at interval finishes.
But, receiver must be before removing GI, the correct original position of the time domain sampled signal of decision input FFT device 111, and promptly ISI could be effectively avoided on the border of symbol.Therefore, how to carry out suitable symbol boundary detection (symbol boundary detection), just become a very important problem.
In ofdm system 100, package or frame (frame) are middle can to transmit the periodically short targeting signal (short preamble) of one section known tool time domain earlier, supplies the usefulness of the Synchronous Processing of time domain; Then can transmit the frequency pilot sign (pilot symbol) of one section known frequency-region signal, or be called long preamble (longpreamble), supply the usefulness of the channel estimating of frequency domain, so that in follow-up data symbol (data symbol), carry out the frequency domain channel compensation.Before the long preambles time-domain signal, add segment protect interval (representing), and before each data symbol, also add protection interval (representing), to avoid ISI with GI with GI2.Fig. 2 has promptly shown the frame framework of general ofdm signal.As shown in Figure 2, short targeting signal normally is made up of the time domain cycle symbol of certain auto-correlation of tool (auto-correlation) characteristic, and adds long preambles symbol and follow-up data symbol respectively thereafter.
Detect in the way in known boundary symbol, receiver generally is cycle and the autocorrelation performance that utilizes short targeting signal, decides the suitable starting point of long preambles symbol and subsequent data symbols, in order to removing GI, and as the initial foundation of follow-up FFT input.This way generally can be divided into two parts:
The first, the sampled signal of institute's received frame is delivered to the delay correlator (sliding delaycorrelator) that slides, observed its output result.This compute mode that postpones correlator of sliding is as follows:
c k = Σ n = 0 N - 1 r k - n · r k - n - N * Formula (1-1)
This computing is that the sampling range that the sampling range N preceding with it that a N is ordered ordered is carried out related calculation, and the sampling range that this N is ordered can be done the renewal of slip when novel sampling location produces.In the formula (1-1), r kBe k sampling value of institute's received frame, N is the number of samples in the short targeting signal one-period, c kThen postpone k output valve of correlator for sliding.Postpone the computation performance of correlator according to sliding, when the signal that is received was periodic signal, its output absolute value can reach maximum.In view of the above, the output absolute value that postpones correlator that slides can produce maximum when short targeting signal is received, and is presenting relative smaller value At All Other Times.Therefore, can detect whether receive short targeting signal by this comparison of exporting an absolute value and a critical value (threshold).When the output absolute value was incremented to greater than this critical value by relative smaller value, expression detected frame (promptly beginning the reception of short targeting signal); Thereafter when the output absolute value was decremented to less than this critical value, the protection that expression detects the long preambles symbol (promptly finished the reception of short targeting signal) at interval.Fig. 3 i.e. the schematic diagram of a mechanism for this reason.
The second, the sampled signal of institute's received frame is delivered to short targeting signal matched filter (matchedfilter).This matched filter be symbol with known short targeting signal for being several, do plural linear regression computing with sampled signal.Its compute mode is as follows:
z k = Σ n = 0 N - 1 r k - n · p n * Formula (1-2)
Wherein, r kBe k sampling value of institute's received frame, p nBe known short targeting signal symbol, N is the number of samples in the short targeting signal one-period, z kThen be k output result of matched filter.Because short targeting signal has certain autocorrelation performance usually, so the output of matched filter can present the estimation result of time domain channel impulse response.In addition, because the periodicity of short targeting signal itself, as if being the output result that length window is observed matched filter with the N point, the estimated value of channel impulse response equally also can present in periodic mode in window.Fig. 4 promptly is the schematic diagram of this mechanism.
In known way, two shortcomings are arranged at present.First, when decision character boundary reference point, be the peak-peak (peak value) that detects earlier in the watch window, make one section initial stage scope (Early Range) forward according to this peak-peak again, to contain preceding cursor (Pre-Cursor) response of channel impulse response.The initial stage scope can be relevant with the border of watch window herein.Suppose peak-peak forward x sampling point be initial stage scope starting point, and the initial borderline phase of peak-peak and place window is apart from y sampling point.If x＜=y, then initial stage scope starting point promptly is y-x place backward, the initial border of place window, to peak-peak, is the initial stage scope from described starting point, shown in Fig. 5 (a); If x＞y, then initial stage scope starting point promptly is place window end boundary x-y place forward, and at this moment, the initial stage scope comprises from the end boundary of starting point up to window, again from the initial border of window to peak-peak, shown in Fig. 5 (b).In this initial stage scope, receiver is chosen the position of fixing several sampling points from peak-peak again, as the character boundary reference point.The fixing way of this kind lacks flexibility, and long or when having a plurality of relative high peaks in the response of preceding cursor, can cause the erroneous judgement of reference point, influences the usefulness of receiver.
The second, postponing under the bigger channel circumstance of diffusion (Delay Spread), often because of delay misestimates long preambles symbol protection appearance at interval, and then erroneous judgement long preambles symbol and subsequent data symbols enter the opportunity of FFT device 111.
Summary of the invention
Main purpose of the present invention provides a kind of symbol boundary detection devices and methods therefor.This checkout gear utilizes a critical value to come auxiliary judgment, so that choose suitable character boundary reference point in the scope in the early stage.This critical value can be set in response to different system elasticity.This checkout gear comprises a matched filter, a border detector, a detecting unit, and time schedule controller, in order to the symbol initial point of decision package.
In addition; if package comprises frequency pilot sign and protects at interval, then this checkout gear utilizes frequency pilot sign protection matched filter at interval, when receiving the protection interval of targeting signal and frequency pilot sign; produce different output respectively, use the protection interval that judges whether to receive frequency pilot sign.
For the ease of further understanding the present invention, the present invention is described in detail with instantiation below in conjunction with accompanying drawing.
Description of drawings
Fig. 1 is the block diagram of typical Orthodoxy Frequency Division Multiplex (OFDM) system;
Fig. 2 is the schematic diagram of the frame framework of general ofdm signal;
Fig. 3 utilizes in the located by prior art to slide to postpone correlator detection frame and frequency pilot sign protection schematic diagram at interval;
Fig. 4 utilizes short targeting signal matched filter to observe the schematic diagram of channel impulse response estimated value in the located by prior art;
Fig. 5 is the schematic diagram of decision initial stage scope starting point in watch window;
Fig. 6 is the block diagram of symbol boundary detection device of the present invention;
Fig. 7 is the schematic diagram of the present invention's picks symbols border reference point in the initial stage scope;
Fig. 8 is the block diagram of a specific embodiment of Fig. 6 detecting unit;
Fig. 9 is the block diagram of another specific embodiment of Fig. 6 detecting unit;
Figure 10 is the block diagram of the another specific embodiment of Fig. 6 detecting unit;
Figure 11 is the action flow chart of symbol boundary detection method of the present invention.
Description of reference numerals: 100-OFDM system; 101-signal map device; The 102-IFFT device; 103-increases protection circuit at interval; The 104-serialiser; The 105-digital to analog converter; The 106-channel; The 107-analog to digital converter; 109-removes protection circuit at interval; 110-serial parallel converters; The 111-FFT device; The 112-channel compensation device; The 113-signal is separated mapping device; 60-symbol boundary detection device; The short targeting signal matched filter of 61-; The 62-edge detector; The 63-detecting unit; The 64-time schedule controller; 81-slides and postpones correlator; The 82-comparator; The 83-power detector; The 91-GI2 matched filter; 92-second comparator; The motion flow of 1101 ~ 1106-symbol boundary detection method of the present invention.
Embodiment
Ofdm system 100 with Fig. 1 is an example below, and embodiments of the present invention are described in detail in detail.Shown in Figure 2 as described above, ofdm system 100 passes the frame of receiving and has periodic short targeting signal, long preamble (comprising frequency pilot sign and its protection GI2 at interval) and data symbol and its protection interval GI in regular turn.Also the interior number of samples of one-period of the short targeting signal of supposition is N herein.Fig. 6 is the block diagram that cooperates the symbol boundary detection device 60 that this kind frame framework carried for the present invention.As shown in Figure 6, checkout gear 60 comprises a short targeting signal matched filter 61, the sampled signal r of its received frame k, carry out computing suc as formula (1-2).When receiving the part of short targeting signal, the estimated value of the channel impulse response of matched filter 61 meeting output OFDM systems 100.
Checkout gear 60 also comprises a border detector 62, be coupled to short targeting signal matched filter 61, to choose the peak-peak of matched filter 61 outputs, then determine one first critical value according to this peak-peak, and according to the determining positions initial stage scope of peak-peak, the position of peak-peak is as initial stage scope terminal point herein.At last, choose in this initial stage scope, its value is greater than the position of the sampled signal of the starting point of first critical value and the most close this initial stage scope, as the character boundary reference point.Wherein, choosing the part of peak-peak, edge detector 62 is to be that the window that N is ordered is observed the output valve of matched filter 61 with length, and calculates the mean value of the corresponding points in a plurality of different windows.For example: with a length is that 16 window is an example, and this window can be observed the value of per 16 continuous sampled signals in the short targeting signal in regular turn.Obtain peak-peak according to those sampled signal values again.For example: this window is observed earlier in short targeting signal, first observation group of taking a sample, i.e. and the value of the 1st ~ 16 sampled signal, selecting wherein again, the maximum is a peak-peak.Afterwards, observe the second sampling observation group again, the i.e. value of the 17th ~ 32 sampled signal, then, calculate again in the adjacent two sampling observation groups, corresponding two sampled signals, for example: the 1st sampled signal and the 17th sampled signal, the 2nd sampled signal and the 18th sampled signal ..., to the sample mean of the 16th sampled signal and the 32nd sampled signal.Try to achieve after all sample means, selecting wherein, the maximum is peak-peak.Wherein, this mean value can be arithmetic mean, geometric average or exponential average ... or the like various forms of mathematical means.
According to this peak-peak pairing position in this window, and the length of this initial stage scope of presetting in advance, then can be used to determine initial stage scope starting point.For example: the mean value of supposing the 10th and the 26th sampled signal is peak-peak, represents that then the signal of the 10th sampling point of this window has peak-peak.The length of supposing this initial stage scope is 8, and then the 2nd of this window the sampling point then is initial stage scope starting point, and the initial stage scope is 10 sampling points of the 2nd sampling point to the of this window, and this is the situation that the initial stage scope shown in Fig. 7 (a) surpasses window edge.Another situation is that the mean value of supposing the 2nd and the 18th sampled signal is peak-peak, represents that then the signal of the 2nd sampling point of this window has peak-peak.The length of supposing this initial stage scope is 8, the individual sampling point of inverse the 6th (8-2) of this window then, promptly the 11st sampling point position is the starting point of initial stage scope, and the initial stage scope is 16 sampling points of this window the 11st sampling point to the, and 2 sampling points of the 1st sampling point to the, this is the situation that the initial stage scope shown in Fig. 7 (b) surpasses window edge.
In addition, try to achieve after the peak-peak, edge detector 62 can give suitable weight with peak-peak earlier in response to the characteristic of peer machine, is used as first critical value.Weight is excessive, and first critical value is just higher, make it easily the selected character boundary point in back after, and cause the symbol of actual treatment to be subjected to the interference of next symbol, cause ISI; Weight is too small, and first critical value is then on the low side, easily make selected character boundary point before, in postponing the bigger channel of diffusion, cause the actual symbol boundary point to be subjected to the interference of previous symbol, may form serious ISI.The deciding means of the weight of peak-peak is that the characteristic of channel by this communication system of actual emulation decides.After the decision of first critical value, 62 of edge detectors are chosen in this initial stage scope, and its value is greater than the position of the sampled signal of the starting point of first critical value and the most close this initial stage scope, as the character boundary reference point.The selection mechanism of the character boundary reference point that edge detector 62 is implemented can be represented by Fig. 7 (a) and schematic diagram (b).
Checkout gear 60 also comprises a detecting unit 63, is used to detect the protection at interval reception of (be GI2) of receiver to frequency pilot sign.Fig. 8 is the block diagram of a specific embodiment of Fig. 6 detecting unit 63.In the embodiment of Fig. 8, detecting unit 63 comprises a slip and postpones correlator 81, with the sampled signal r of institute's received frame kIn the N sampling range of ordering, carry out related operation with another sampling range behind its delay N point suc as formula (1-1).Detecting unit 63 also comprises a comparator 82, being coupled to slide to postpone correlator 81 and time schedule controller 64, postpones the output valve and one second critical value of correlator 81 in order to relatively to slide, when output valve less than second critical value, judge that promptly receiver has received GI2.Detecting unit 63 also comprises a power detector 83, according to the sampled signal r of institute's received frame kCalculate a reference power,, so dynamically adjust second critical value, avoid because of sampled signal r with as second critical value kInstability (as noise jamming) itself, and cause the erroneous judgement of comparator 82.
Fig. 9 is the block diagram of another specific embodiment of Fig. 6 detecting unit 63.In the embodiment of Fig. 9, detecting unit 63 comprises a GI2 matched filter 91, the sampled signal r of its received frame kBecause GI2 there is no special their cross correlation (cross-correlation) with short targeting signal, and GI2 itself also has autocorrelation performance to a certain degree, so GI2 matched filter 91 is understood the output that produces noise level at short targeting signal reception period, and when receiving, GI2 produces the estimated value of the channel impulse response of ofdm system 100.Detecting unit 63 also comprises one second comparator 92, be coupled to edge detector 62, GI2 matched filter 91 and time schedule controller 64, the peak-peak that is provided according to edge detector 62 determines one the 3rd critical value, and the output valve and the 3rd critical value of comparison GI2 matched filter 91, when output valve greater than the 3rd critical value, judge that promptly receiver has received GI2.In another specific embodiment, can be with the embodiment of the detecting unit 63 of Fig. 8 and Fig. 9, utilize one or door (OR gate) merge and use, as shown in figure 10.
Checkout gear 60 also comprises time schedule controller 64, be coupled to edge detector 62 and detecting unit 63, according to the selected character boundary reference point of edge detector 62 and the testing result of detecting unit 63, decide the starting point of long preambles symbol and subsequent data symbols.In the embodiment of Fig. 8 to Figure 10, when detecting unit 63 judges that receiver has received GI2 in certain watch window, time schedule controller 64 can be according to the length (being generally the integral multiple of N) of GI2, with the character boundary reference point in follow-up certain window, starting point as the long preambles symbol, and the starting point of data symbol also can be calculated out by this.After the starting point of decision symbol, promptly may command removes protection circuit 109 at interval, to remove the protection interval of long preambles symbol and subsequent data symbols, imports FFT device 111 again.
Then, will narrate and how utilize aforesaid symbol boundary detection device 60, implement symbol boundary detection method of the present invention.Figure 11 is the action flow chart of symbol boundary detection method of the present invention.As shown in figure 11, this detection method comprises the following step:
1101 utilize short targeting signal matched filter 61 to receive short targeting signal, with the channel impulse response of estimation ofdm system 100;
1102 edge detectors 62 are the output valve that window that N is ordered is observed matched filter 61 with length;
1103 edge detectors 62 calculate the mean value of the corresponding points in a plurality of different windows, and choose peak-peak wherein;
1104 edge detectors 62 determine a critical value according to this peak-peak, and determine an initial range according to the relative position of this peak-peak, choose in this window sampling point, as the character boundary reference point greater than this critical value and the most close initial stage scope starting point;
1105 detecting units 63 detect receiver and whether receive GI2; And
1106 time schedule controllers 64 determine the starting point of long preambles symbol according to the testing result of character boundary reference point and step 1105.
In one embodiment, step 1105 comprises: (a1) sampling range of ordering according to a N in the sampled signal that utilizes institute's received frame, and another sampling range of ordering with preceding N carries out the related operation suc as formula (1-1); (a2) sampled signal according to institute's received frame calculates reference power, as second critical value; And the result and second critical value that (a3) compare this related operation, whether receive GI2 to judge receiver.
In another specific embodiment, step 1105 item comprises: (a1) utilize a GI2 matched filter to receive the sampled signal of GI2, and the estimated value of the channel impulse response of output OFDM system 100; (a2) peak-peak of choosing according to step 1103 determines one the 3rd critical value; And the output valve and the 3rd critical value that (a3) compare the GI2 matched filter, whether receive GI2 to judge receiver.
More than utilize preferred embodiment to describe the present invention in detail, but not limit the scope of the invention.Those skilled in the art will be seen that, suitably do slightly change and adjustment, will not lose main idea of the present invention place, also do not break away from the spirit and scope of the present invention.

Claims (11)

1. symbol boundary detection device is used for a receiver of a communication system, and described receiver receives a package, and described package comprises plurality of fields, and these fields comprise one first targeting signal and a symbol at least, and described checkout gear comprises:
One matched filter receives first targeting signal, and to export an estimating signal, wherein, described estimating signal is corresponding to a channel impulse response of communication system;
One border detector is coupled to matched filter, according to estimating signal, obtains a critical value and an initial stage scope, and determines a character boundary reference point according to critical value and initial stage scope;
One detecting unit is used to detect corresponding field, exports a detection signal; And
Time schedule controller is coupled to edge detector and detecting unit, according to character boundary reference point and detection signal, and a starting point of decision symbol.
2. checkout gear as claimed in claim 1, wherein these etc. field also comprise one second targeting signal, between first targeting signal and symbol, detecting unit is used to detect second targeting signal, output detection signal.
3. checkout gear as claimed in claim 1, wherein edge detector at first determines a peak-peak of estimating signal, again according to peak-peak decision critical value and initial stage scope, again according to critical value and initial stage scope decision character boundary reference point.
4. checkout gear as claimed in claim 3, wherein these sampled signals are divided into a plurality of sampled signal groups, each sampled signal group all comprises a N continuous sampled signal, wherein, these sampled signal groups comprise one first adjacent sampled signal group and one second sampled signal group, the first sampled signal group also comprises one first sampled signal, the second sampled signal group also comprises one second sampled signal, first sampled signal in the position of the first sampled signal group corresponding to the position of secondary signal in the second sampled signal group, a plurality of sample means are corresponding with first sampled signal and second sampled signal respectively, and peak-peak is the maximum of these sample averaging numbers.
5. checkout gear as claimed in claim 4, wherein, the character boundary reference point be corresponding to sampled signal greater than critical value and near the sampling point of initial stage scope starting point.
6. checkout gear as claimed in claim 2, wherein detecting unit comprises:
One slides postpones correlator, carries out a related operation according to second targeting signal, exports a coherent signal; And
One comparator, being coupled to slides postpones correlator and time schedule controller, compares coherent signal and one second critical value, and output detection signal.
7. checkout gear as claimed in claim 2, wherein detecting unit comprises:
One second matched filter is exported one second estimating signal according to second targeting signal, and second estimating signal is corresponding to the channel impulse response of communication system; And
One second comparator is coupled to edge detector, second matched filter and time schedule controller, and according to first estimating signal and second estimating signal, the decision detection signal.
8. symbol boundary detection method is used for a receiver of a communication system, the package that receiver receives, and described package comprises plurality of fields, and described field comprises one first targeting signal and a symbol at least, and described detection method comprises:
According to first targeting signal, export one first estimating signal, wherein, first estimating signal is corresponding to a channel impulse response of communication system;
According to first estimating signal, determine a critical value and an initial stage scope;
According to critical value and initial stage scope, determine a character boundary reference point;
According to corresponding field, export a detection signal; And
According to character boundary reference point and detection signal, a starting point of decision symbol.
9. as 8 described detection methods of claim the, wherein, first estimating signal comprises a plurality of sampling points, and these sampling points are corresponding a plurality of sampled signals respectively, and wherein, according to first estimating signal, the step of decision critical value and initial stage scope comprises:
These sampled signals are divided into a plurality of sampled signal groups, wherein, each sampled signal group all comprises a N continuous sampled signal, these sampled signal groups comprise one first adjacent sampled signal group and one second sampled signal group, the first sampled signal group also comprises one first sampled signal, the second sampled signal group also comprises one second sampled signal, and first sampled signal is corresponding in the position of the second sampled signal group with secondary signal in the position of the first sampled signal group;
Determine a plurality of sample means according to these sampled signal groups, wherein, these capture mean values are corresponding with first sampled signal and second sampled signal respectively;
The maximum of selecting these sample averaging numbers is as peak-peak; And
According to peak-peak, decision critical value and initial stage scope.
10. detection method as claimed in claim 8, wherein the output detection signal step comprises:
Carry out a related operation; And
The result and one second critical value that compare related operation are with output detection signal.
11. detection method as claimed in claim 8, wherein these fields also comprise one between first targeting signal and symbol second targeting signal, the output detection signal step comprises:
Export one second estimating signal according to second targeting signal, second estimating signal is corresponding to the channel impulse response of communication system; And
According to first estimating signal and second estimating signal, the decision detection signal.
CNA03150129XA 2003-07-18 2003-07-18 Apparatus and method for symbol border detecting Pending CN1571311A (en)

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101136919B (en) * 2007-05-24 2010-09-08 中兴通讯股份有限公司 Pulse matching method used for baseband signal demodulation
CN103210621A (en) * 2010-08-27 2013-07-17 兰蒂克德国有限责任公司 Robust preamble for communication over noisy media
CN103460629A (en) * 2010-12-10 2013-12-18 阿尔卡特朗讯 Coherent optical receiver for pilot-assisted data transmission
CN113630351A (en) * 2020-05-08 2021-11-09 瑞昱半导体股份有限公司 Symbol boundary detection method and processor
CN113630351B (en) * 2020-05-08 2024-05-31 瑞昱半导体股份有限公司 Symbol boundary detection method and processor

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101136919B (en) * 2007-05-24 2010-09-08 中兴通讯股份有限公司 Pulse matching method used for baseband signal demodulation
CN103210621A (en) * 2010-08-27 2013-07-17 兰蒂克德国有限责任公司 Robust preamble for communication over noisy media
CN103210621B (en) * 2010-08-27 2016-06-22 兰蒂克德国有限责任公司 The robust preamble communicated in noise media
CN103460629A (en) * 2010-12-10 2013-12-18 阿尔卡特朗讯 Coherent optical receiver for pilot-assisted data transmission
CN103460629B (en) * 2010-12-10 2016-06-15 阿尔卡特朗讯 For the coherent optical heterodyne communicatio of the auxiliary transfer of data of pilot tone
CN113630351A (en) * 2020-05-08 2021-11-09 瑞昱半导体股份有限公司 Symbol boundary detection method and processor
CN113630351B (en) * 2020-05-08 2024-05-31 瑞昱半导体股份有限公司 Symbol boundary detection method and processor

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Open date: 20050126