CN101155155B - Channel estimating device with optimized search and method thereof - Google Patents
Channel estimating device with optimized search and method thereof Download PDFInfo
- Publication number
- CN101155155B CN101155155B CN2006101393681A CN200610139368A CN101155155B CN 101155155 B CN101155155 B CN 101155155B CN 2006101393681 A CN2006101393681 A CN 2006101393681A CN 200610139368 A CN200610139368 A CN 200610139368A CN 101155155 B CN101155155 B CN 101155155B
- Authority
- CN
- China
- Prior art keywords
- channel
- unit
- information
- translation
- frequency response
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Images
Landscapes
- Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)
- Digital Transmission Methods That Use Modulated Carrier Waves (AREA)
Abstract
The invention provides a channel evaluating device and method with optimization search. The channel evaluating device comprises a channel evaluating unit of time axis, a peak value sensing module, a first shifting unit, a channel evaluating unit of frequency domain axis, and a shift optimization searching module. The channel evaluating unit of time axis is used to implement the channel evaluationof time dimension and evaluates the initial channel frequency response. The peak value sensing module outputs the information of peak value. The shift optimization searching module decides the best shift information based on the information of peak value, feedback signal and integrated channel frequency response. The first shifting unit adjusts the position of initial channel frequency response on time field according to the best shift information. The channel evaluating unit of frequency domain axis performs the channel evaluation of time dimension and evaluates the integrated channel frequency response.
Description
Technical field
The present invention relates to a kind of channel estimating apparatus, and be particularly related to a kind of channel estimating apparatus that has optimized search in the coherent OFDM system that is applied in.
Background technology
In recent years, OFDM (orthogonal frequency division multiplexing, OFDM) system is because of having high-speed transfer, frequency range service efficiency height and to disturbing (inter symbol interference) that advantages such as good resistivity are arranged between channel latency and symbol unit, and is widely used in digital video broadcast-terrestrial (DVB-T) system, WLAN (WLAN) digital audio broadcasting (DAB) system.Ofdm system can be divided into relevant (coherent) ofdm system and incoherent (non-coherent) ofdm system according to applied modulation (demodulate) technology.In the coherent OFDM system, in order to reach reliable coherent detection and to compensate the destruction that received signal causes because of channel variation, receiving terminal must have the precise channels estimation, could correctly determine the symbol unit in the received signal.
The coherent OFDM system adopts pilot data (pilot) to carry out channel estimating usually, and for example U.S. Patent application discloses US20030138060 number disclosed a kind of Coded Orthogonal Frequency Division Multiplexing (COFDM) demodulator (COFDMmodulator with an optimal FFT analysis window positioning) with best fast fourier transform analysis window position in early days.Yet this demodulator is in the process of carrying out channel estimating, do not weigh the shared influence in the decision-making translation information of subcarrier channel frequency response, therefore according to maximum likelihood estimate (MaximumLikelihood Estimation), the translation information that this demodulator adopted not is to be optimization.Moreover in order to reduce the error of channel estimating, this demodulator must could produce preferable translation information via a large amount of operation times.In other words, this demodulator not only can't reach optimized channel estimating, and the effective operating rate of elevator system.
In addition, disclose in early days the delay expansion (delay spread) that utilizes for 1580951A2 number in the channel impulse response (channel impulse response) as european patent application and estimate and the required translation information of frequency interpolation filter (frequency interpolation filter), but its unspecified delay expansion that how to obtain in the channel impulse response.
Summary of the invention
The purpose of this invention is to provide a kind of channel estimating apparatus with optimized search, utilize peak information to promote the operating rate of channel estimating apparatus, and in the process of calculating translation information, include the subcarrier channel frequency response in consideration, cause channel estimating apparatus to have the optimization translation information, and then effectively promote the accuracy of channel estimating apparatus.
Another object of the present invention provides a kind of channel estimating and measuring method with optimized search, in order to the accuracy and the operating rate of effective lifting channel estimating apparatus.
In order to reach above-mentioned or other purpose, the present invention proposes a kind of channel estimating apparatus with optimized search, be applicable to demodulating equipment, wherein demodulating equipment is exported frequency domain received signal and feedback signal, and channel estimating apparatus is in order to estimate complete channel frequency response and best translation information from the frequency domain received signal according to feedback signal.Channel estimating apparatus comprises time shaft channel estimation unit, peak sensing module, first translation unit, frequency domain axle channel estimation unit and translation optimized search module.The time shaft channel estimation unit is in order to receiving the frequency domain received signal, and carries out the channel estimation of time dimension according to the scattered pilots data in the frequency domain received signal, to estimate the initial channel frequency response.The peak sensing module is in order to the peak of detecting initial channel frequency response on time domain, to export as peak information.First translation unit is in order to adjusting the relative position of initial channel frequency response on frequency domain according to best translation information, and produces the numerical value of adjusting back initial channel frequency response.Frequency domain axle channel estimation unit is carried out the channel estimation of frequency domain dimension, and is obtained complete channel frequency response in order to adjusting the numerical value of back initial channel frequency response.Translation optimized search module produces a plurality of translation information according to peak information, and from these translation information, utilize feedback signal and the complete channel frequency response best translation information of making a strategic decision out, wherein feedback signal is the output signal of the translation unit in the demodulating equipment or the output signal of correcting unit, and translation optimized search module comprises: the transmission parameter unit, a plurality of comparison transmission parameters are provided, and described a plurality of comparison transmission parameters remove corresponding these transmission parameters respectively one to one; Acquisition unit in order to the output signal that captures the translation unit in the demodulating equipment or the transmission parameter in the output signal of correcting unit, and captures a plurality of subcarrier channel frequency responses of these transmission parameters of carrying from complete channel frequency response; Computing unit, these are compared these transmission parameters that transmission parameter, acquisition unit capture and the numerical value of these subcarrier channel frequency responses carries out computing according to maximum likelihood estimate, producing many result of calculations, and computing unit obtains and exports decision information from these result of calculations; And decision package, produce these translation information according to peak information, and utilize decision information from these translation information, to select an output, with as best translation information.
The invention allows for a kind of channel estimating apparatus with optimized search, be applicable to demodulating equipment, demodulating equipment comprises fast Fourier transform unit, translation unit, correcting unit, and signal processing module, fast Fourier transform unit produces the frequency domain received signal, demodulating equipment is by the frequency domain received signal, select an output in the output signal of translation unit and the output signal of correcting unit with as feedback signal, channel estimating apparatus is in order to estimate complete channel frequency response and best translation information from the frequency domain received signal according to feedback signal, its frequency domain received signal comprises that a plurality of symbols are first, each symbol unit comprises scattered pilots data and transmission parameter, channel estimating apparatus comprises: the time shaft channel estimation unit, in order to receive the frequency domain received signal, and according to the formed channel information of these scattered pilots data, carry out the channel estimation of time dimension, to estimate the initial channel frequency response; The peak sensing module is in order to the peak of detecting initial channel frequency response on time domain, to export as peak information; First translation unit is adjusted the relative position of initial channel frequency response on frequency domain according to best translation information, and produces the numerical value of adjusting back initial channel frequency response; Frequency domain axle channel estimation unit in order to adjusting the numerical value of back initial channel frequency response, is carried out the channel estimation of frequency domain dimension, and is obtained complete channel frequency response; And translation optimized search module, produce a plurality of translation information according to peak information, from these translation information, to utilize feedback signal and the complete channel frequency response best translation information of making a strategic decision out, wherein feedback signal is the frequency domain received signal, and translation optimized search module comprises: the transmission parameter unit, a plurality of comparison transmission parameters are provided, and these comparison transmission parameters remove corresponding these transmission parameters respectively one to one; The acquisition translation unit, in order to the transmission parameter in acquisition and the adjustment frequency domain received signal, and the acquisition translation unit captures a plurality of subcarrier channel frequency responses of these transmission parameters of carrying from complete channel frequency response; Computing unit, according to maximum likelihood estimate these are compared transmission parameter, acquisition these transmission parameters that translation unit captured and adjusted and the numerical value of these subcarrier channel frequency responses and carry out computing, and then produce many result of calculations, and computing unit obtains and exports decision information from these result of calculations; And decision package, produce these translation information according to peak information, and utilize decision information from these translation information, to select an output, with as best translation information; Wherein capture translation unit according to these transmission parameters in these translation information adjustment frequency domain received signals.
From another viewpoint, the present invention has proposed a kind of channel estimating and measuring method with optimized search in addition, be applicable to demodulating equipment, wherein demodulating equipment is exported frequency domain received signal and feedback signal, and channel estimating and measuring method is in order to estimate complete channel frequency response and best translation information from the frequency domain received signal according to feedback signal.Channel estimating and measuring method comprises reception frequency domain received signal, and its frequency domain received signal comprises that a plurality of symbols are first, and each symbol unit comprises scattered pilots data and transmission parameter.Afterwards, according to the formed channel information of scattered pilots data, carry out the channel estimation of time dimension, to estimate the initial channel frequency response.For the initial channel frequency response being adjusted to the optimization position on the frequency domain axle, at first,, produce peak information from the peak of detecting initial channel frequency response on time domain.Thus, go out best translation information according to peak information and feedback signal decision-making.Wherein, the step that goes out best translation information according to peak information and feedback signal decision-making comprises: produce a plurality of translation information according to peak information; Adjust the relative position of initial channel frequency response on frequency domain one by one according to each translation information, and, carry out the channel estimation of frequency domain dimension, to estimate complete channel frequency response to the numerical value of adjusted these initial channel frequency responses; When feedback signal is the output signal of translation unit in the demodulating equipment or the output signal of correcting unit, from feedback signal, capture transmission parameter, and from complete channel frequency response, capture the carrying these transmission parameters a plurality of subcarrier channel frequency responses, and the numerical value of a plurality of comparison transmission parameters, those transmission parameters that captured and those subcarrier channel frequency responses is carried out computing according to maximum likelihood estimate, producing many first result of calculations, and from those first result of calculations, obtain decision information; And when feedback signal is the frequency domain received signal, transmission parameter in acquisition and the adjustment feedback signal, and from complete channel frequency response, capture the carrying these transmission parameters those subcarrier channel frequency responses, and according to maximum likelihood estimate those are compared transmission parameter, these transmission parameters that capture and adjust and the numerical value of these subcarrier channel frequency responses and carry out computing, producing many second result of calculations, and from these second result of calculations, obtain this decision information; And utilize decision information from these translation information, to select one as best translation information.Thus, just can adjust the relative position of initial channel frequency response on frequency domain according to best translation information.At last, to the numerical value of adjusted initial channel frequency response, carry out the channel estimation of frequency domain dimension, to estimate complete channel frequency response.
The present invention utilizes peak information to promote the operating rate of channel estimating apparatus, and because of weighing the influence of subcarrier channel frequency response for translation information, causes channel estimating apparatus to have the optimization translation information, and effectively promote the accuracy of channel estimating apparatus.
For above and other objects of the present invention, feature and advantage can be become apparent, preferred embodiment cited below particularly, and conjunction with figs. are described in detail below.
Description of drawings
Fig. 1 is according to the described Organization Chart with channel estimating apparatus of optimized search of a preferred embodiment of the present invention.
The signal schematic representation of Fig. 2 for being illustrated in order to key diagram 1.
Fig. 3 is the Organization Chart according to the described translation optimized search of preferred embodiment of the present invention module.
Fig. 4 is the Organization Chart according to described another translation optimized search module of preferred embodiment of the present invention.
Fig. 5 is the Organization Chart according to the described another translation optimized search module of preferred embodiment of the present invention.
Fig. 6 is the Organization Chart according to the described peak sensing module of preferred embodiment of the present invention.
Fig. 7 is according to the described flow chart with channel estimating and measuring method of optimized search of a preferred embodiment of the present invention.
The explanation of Reference numeral
100: channel estimating apparatus
101: the time shaft channel estimation unit
102: the peak sensing module
103: the first translation unit
104: frequency domain axle channel estimation unit
105: translation optimized search module
106: the channel status evaluation unit
200: demodulating equipment
201: fast Fourier transform unit
202: translation unit
203: correcting unit
204: signal processing module
301,401: acquisition unit
302,402,502: the transmission parameter unit
303,403,503: computing unit
304,404,504: decision package
501: the acquisition translation unit
601: contrary fast Fourier transform unit
602: the peak sensing unit
S701～S706: flow chart step
Embodiment
Major technology of the present invention is characterized as to be utilized peak information to reduce translation optimized search module to reach the calculation times that optimization institute must spend, and in the process of optimized search module decision-making translation information, include the subcarrier channel frequency response in consideration, cause channel estimating apparatus of the present invention to have good accuracy and operating rate.Below will illustrate channel estimating apparatus of the present invention, but it is not in order to limit the present invention, to have the knack of this operator and can modify slightly following embodiment according to spirit of the present invention, as long as it still belongs to scope of the present invention.
Fig. 1 is according to the described Organization Chart with channel estimating apparatus of optimized search of a preferred embodiment of the present invention.The channel estimating apparatus 100 of present embodiment comprises time shaft channel estimation unit 101, peak sensing module 102, first translation unit 103, frequency domain axle channel estimation unit 104 and translation optimized search module 105.For convenience of description, Fig. 1 shows the demodulating equipment 200 that channel estimating apparatus 100 is suitable for, and wherein demodulating equipment 200 comprises fast Fourier transform unit 201, translation unit 202, correcting unit 203 and signal processing module 204.
Illustrate further, above-mentioned fast Fourier transform unit 201 is in order to carry out the computing of fast fourier transform, and fast Fourier transform unit 201 utilizes positional information Sp to judge the computing starting point of the signal TS that desire receives, and produces frequency domain received signal FS after computing.Translation unit 202 is in order to adjust the relative position of frequency domain received signal FS on frequency domain according to best translation information SV.The operation of correcting unit 203 in order to the output signal RFS of translation unit 202 is proofreaied and correct according to complete channel frequency response EC.Signal processing module 204 is in order to carry out the associative operation of demodulation and decoding, with the data Data among the output signal TS.
Continuation is with reference to Fig. 1, the channel estimating apparatus 100 of present embodiment is in order to estimate complete channel frequency response EC and best translation information SV according to feedback signal FBS from frequency domain received signal FS, wherein feedback signal FBS be the output signal RFS of frequency domain received signal FS, translation unit 202 and correcting unit 203 output signal CS one of them.
With reference to the signal schematic representation that Fig. 2 illustrated.Above-mentioned frequency domain received signal FS comprises a plurality of symbols unit, and (Fig. 2 only shows Fu Yuan SB0～SB7), accord with first SB0～SB7 and comprise data, scattered pilots data (scatter pilot), transmission parameter signaling (transmission parameter signaling, TPS), wherein the white round dot of Fig. 2 is represented data, the black round dot is represented the scattered pilots data, the oblique line round dot represents to carry out the data of channel estimating, and transmission parameter is carried on several subcarriers arranged side by side (Fig. 2 does not indicate).In addition, the carrier wave that transmits the first SB0～SB7 of symbol comprises a plurality of subcarriers (Fig. 2 only shows wherein several subcarriers), for example K subcarrier is in different time points, and carrying accords with data or the scattered pilots data among first SB0～SB7 respectively, and wherein K is the integer greater than 0.
Channel estimating mainly is to estimate the affiliated subcarrier channel frequency response of each subcarrier, to compensate the destruction that frequency domain received signal FS causes because of channel variation.The channel estimating apparatus 100 of present embodiment adopts the two-dimensional interpolation method to carry out channel estimating, and wherein the two-dimensional interpolation method is equivalent to the realization of two rank one dimension interpolation methods.Therefore, channel estimating apparatus 100 can estimate the subcarrier channel frequency response of part subcarrier earlier via time shaft channel estimation unit 101.Afterwards, estimate the subcarrier channel frequency response of each subcarrier again via frequency domain axle channel estimation unit 104.Wherein the detailed operation principle of channel estimating apparatus 100 is described as follows.
At first, time shaft channel estimation unit 101 is carried out the channel estimation of time dimension to the frequency domain received signal FS that is received, to estimate initial channel frequency response CFR according to the formed channel information of scattered pilots data.For example, time shaft channel estimation unit 101 is utilized K scattered pilots data PS1 and the PS2 that subcarrier carried, and adopts the one dimension interpolation method that data D1～D3 is carried out channel estimating, and this moment, data D1～D3 represented with the oblique line round dot.Thus, the subcarrier (such as K, K+3, a K+6 subcarrier) of the scattered pilots data that carrying is relevant, the subcarrier channel frequency response under it just can be estimated.In other words, above-mentioned initial channel frequency response CFR includes only the subcarrier channel frequency response of part, because do not carry the subcarrier (such as K+1, K+2, K+4, a K+5 subcarrier) of other incoherent scattered pilots data, the subcarrier channel frequency response under it is not estimated as yet.
Before the channel estimating that enters frequency domain axle channel estimation unit 104, first translation unit 103 can be adjusted the relative position of initial channel frequency response CFR on frequency domain earlier according to best translation information SV, and produces the numerical value of adjusting back initial channel frequency response.Afterwards, frequency domain axle channel estimation unit 104 is carried out the channel estimation of frequency domain dimension, and is obtained complete channel frequency response EC in order to adjusting the numerical value of back initial channel frequency response.For example, K+1 and K+2 subcarrier are in different time points institute data carried by data, can be via K numerical value with the subcarrier channel frequency response of K+3 subcarrier, adopt the one dimension interpolation method to carry out channel estimating with K+2 subcarrier institute data carried by data, and then estimate the individual subcarrier channel frequency response with K+2 subcarrier of K+1 K+1.In other words, complete channel frequency response EC comprises the subcarrier channel frequency response of each subcarrier.Therefore, correcting unit 203 just can go to compensate the destruction that frequency domain received signal FS causes because of channel variation according to complete channel frequency response EC.
The mode that above-mentioned best translation information SV produces is as described below.At first, peak sensing module 102 detects the peak of initial channel frequency response CFR on time domain, and output peak information PI.Afterwards, translation optimized search module 105 can produce several translation information according to peak information PI earlier, utilizes feedback signal FBS and complete channel frequency response EC again, and best translation information SV makes a strategic decision out from translation information.
In addition, channel estimating apparatus 100 also comprises channel status evaluation unit 106, and it is in order to estimate channel condition information CSI according to complete channel frequency response EC.Thus, signal processing module 204 just can carry out the associative operation of demodulation and decoding according to channel condition information CSI to the output signal CS of correcting unit.
The described translation optimized search of Fig. 1 module 105 has different framework modes according to different feedback signal FBS, below will list one by one.
Fig. 3 is the Organization Chart according to the described translation optimized search of preferred embodiment of the present invention module 105.As shown in Figure 3, translation optimized search module 105 comprises acquisition unit 301, transmission parameter unit 302, computing unit 303 and decision package 304.Wherein feedback signal FBS is the output signal CS of correcting unit 203.Transmission parameter unit 302 is in order to provide a plurality of comparison transmission parameters, wherein compares transmission parameter and removes transmission parameter among the corresponding frequency domain received signal FS respectively one to one.Acquisition unit 301 is in order to the transmission parameter among the output signal CS that captures correcting unit 203, and captures the subcarrier channel frequency response of carrying transmission parameter from complete channel frequency response EC.Afterwards, computing unit 303 is according to the numerical value of maximum likelihood estimate (MaximumLikelihood Estimation) to comparison transmission parameter, acquisition unit 301 transmission parameter that is captured and the subcarrier channel frequency response that carries transmission parameter, carry out suc as formula the computing shown in (1) and the formula (2), in the hope of result of calculation ML3:
ML3＝Min(L3
-，L3
+)(2)
S wherein
MBe M comparison transmission parameter,
M the transmission parameter that is captured for acquisition unit 301,
Be the numerical value of the subcarrier channel frequency response of the subcarrier that carries M transmission parameter, i is the number of transmission parameter.For example, carrier wave is (each symbol unit is carried by 2048 subcarriers) under the 2K pattern, transmits 17 transmission parameters, then i=17 respectively by 17 fixing subcarriers.If carrier wave is (each symbol unit is carried by 8192 subcarriers) under the 8K pattern, transmit 68 transmission parameters, then i=68 respectively by 68 fixing subcarriers.
On the other hand, decision package 304 produces a plurality of translation information according to peak information PI.Each translation information also all is sent to the translation unit 202 and first translation unit 103, and in other words, every translation information all can produce output signal CS indirectly and complete channel frequency response EC feedbacks to acquisition unit 301.Relatively, computing unit 303 just can produce many result of calculation ML3, and decision information PD3 be obtained and be exported to computing unit 303 from many result of calculation ML3 according to the different output signal of acquisition unit 301.Afterwards, decision package 304 utilizes decision information PD3 to select an output from above-mentioned translation information, with as best translation information SV.
In addition, decision package 304 produces positional information SP in the best translation information SV that makes a strategic decision out.Thus, fast Fourier transform unit 201 is judged the computing starting point of the signal TS that desire receives according to positional information SP.
Fig. 4 is the Organization Chart according to described another translation optimized search module 105 of preferred embodiment of the present invention.As shown in Figure 4, translation optimized search module 105 comprises acquisition unit 401, transmission parameter unit 402, computing unit 403 and decision package 404.Wherein feedback signal FBS is the output signal RFS of translation unit 202.Transmission parameter unit 402 is in order to provide a plurality of comparison transmission parameters, wherein compares transmission parameter and removes transmission parameter among the corresponding frequency domain received signal FS respectively one to one.Acquisition unit 401 is in order to the transmission parameter among the output signal RFS that captures translation unit 202, and captures the subcarrier channel frequency response of carrying transmission parameter from complete channel frequency response EC.Afterwards, computing unit 403 is according to the numerical value of maximum likelihood estimate to comparison transmission parameter, acquisition unit 401 transmission parameter that is captured and the subcarrier channel frequency response that carries transmission parameter, carry out suc as formula the computing shown in (3) and the formula (4), in the hope of result of calculation ML4:
ML4＝Min(L4
-，L4
+)(4)
S wherein
MBe M comparison transmission parameter, R
MM the transmission parameter that is captured for acquisition unit 301,
Be the numerical value of the subcarrier channel frequency response of the subcarrier that carries M transmission parameter, i is the number of transmission parameter.For example, carrier wave is (each symbol unit is carried by 2048 subcarriers) under the 2K pattern, transmits 17 transmission parameters, then i=17 respectively by 17 fixing subcarriers.If carrier wave is (each symbol unit is carried by 8192 subcarriers) under the 8K pattern, transmit 68 transmission parameters, then i=68 respectively by 68 fixing subcarriers.
On the other hand, decision package 404 produces a plurality of translation information according to peak information PI.Each translation information also all is sent to the translation unit 202 and first translation unit 103, and in other words, every translation information all can produce output signal RFS indirectly and complete channel frequency response EC feedbacks to acquisition unit 401.Relatively, computing unit 403 just can produce many result of calculation ML4, and decision information PD4 be obtained and be exported to computing unit 403 from many result of calculation ML4 according to the different output signal of acquisition unit 401.Afterwards, decision package 404 utilizes decision information PD4 to select an output from above-mentioned translation information, with as best translation information SV.
In addition, decision package 404 produces positional information SP in the best translation information SV that makes a strategic decision out.Thus, fast Fourier transform unit 201 is judged the computing starting point of the signal TS that desire receives according to positional information SP.
Fig. 5 is the Organization Chart according to the described another translation optimized search module 105 of preferred embodiment of the present invention.As shown in Figure 5, translation optimized search module 105 comprises acquisition translation unit 501, transmission parameter unit 502, computing unit 503 and decision package 504.Wherein feedback signal FBS is frequency domain received signal FS.Transmission parameter unit 502 is in order to provide a plurality of comparison transmission parameters, wherein compares transmission parameter and removes transmission parameter among the corresponding frequency domain received signal FS respectively one to one.Capture translation unit 501 in order to the transmission parameter among acquisition and the adjustment frequency domain received signal FS, and from complete channel frequency response EC, capture the subcarrier channel frequency response of carrying transmission parameter.Afterwards, computing unit 503 is according to the numerical value of maximum likelihood estimate to the subcarrier channel frequency response of comparison transmission parameter, the acquisition transmission parameter that translation unit 501 captured and adjusted and carrying transmission parameter, carry out suc as formula the computing shown in (5) and the formula (6), in the hope of result of calculation ML5:
ML5＝Min(L5
-，L5
+)(6)
S wherein
MBe M comparison transmission parameter, RI
MBe the transmission parameter after M the translation being captured of acquisition translation unit 501,
Be the numerical value of the subcarrier channel frequency response of the subcarrier that carries M transmission parameter, i is the number of transmission parameter.About the example that the number of transmission parameter can be enumerated with reference to Fig. 3 and Fig. 4 embodiment, do not add narration at this.
On the other hand, decision package 504 produces a plurality of translation information according to peak information PI.Each translation information also all is sent to first translation unit 103, translation unit 202 and acquisition translation unit 501, and wherein capturing translation unit 501 can be according to the transmission parameter among the translation information adjustment frequency domain received signal FS.In other words, every translation information all can produce complete channel frequency response EC back coupling indirectly to capturing translation unit 501.Relatively, computing unit 503 just can produce many result of calculation ML5, and decision information PD5 be obtained and be exported to computing unit 503 from many result of calculation ML5 according to the different output signal of acquisition unit 501.Afterwards, decision package 504 utilizes decision information PD5 to select an output from above-mentioned translation information, with as best translation information SV.
In addition, decision package 504 also produces positional information SP except the best translation information SV that makes a strategic decision out.Thus, fast Fourier transform unit 201 is judged the computing starting point of the signal TS that desire receives according to positional information SP.
What deserves to be mentioned is, as can be known described from Fig. 3～Fig. 5 embodiment, channel estimating apparatus of the present invention (did not produce before the best translation information) before reaching optimization, be number (such as 5), decide feedback signal FBS to feedback to the number of times of translation optimized search module according to translation information.In other words, translation optimized search module reaches the required calculation times of optimization, determines according to the number of translation information.With respect to prior art, prior art is in order to reduce the error rate of channel estimating, must be according to the number (comprising that such as the 2K pattern 2048 subcarriers, 8K pattern comprise 8192 subcarriers) of subcarrier, decide to produce the calculation times that best translation information institute must spend.Therefore, with prior art in comparison, present embodiment will effectively promote the operating rate of channel estimating apparatus.
Fig. 6 is the Organization Chart according to the described peak sensing module 102 of preferred embodiment of the present invention.As shown in Figure 6, peak sensing module 102 comprises contrary fast Fourier transform unit 601 and peak sensing unit 602.Contrary fast Fourier transform unit 601 is in order to be converted to time domain with initial channel frequency response CFR.Peak sensing unit 602 is in order to detect against the peak of the output signal of fast Fourier transform unit, to export as peak information PI.
Except the channel estimating apparatus that is used for demodulating equipment, the present invention also proposes a kind of channel estimating and measuring method that is used for demodulating equipment.Fig. 7 is for according to the described flow chart with channel estimating and measuring method of optimized search of a preferred embodiment of the present invention, and the method flow of this embodiment is just as the work flow of previous embodiment channel estimating apparatus.
At first, receive the frequency domain received signal in step S701, its frequency domain received signal comprises that a plurality of symbols are first, and each symbol unit comprises scattered pilots data and transmission parameter.According to the above-mentioned formed channel information of scattered pilots data, carry out the channel estimation of time dimension, in step S702 to estimate the initial channel frequency response.Afterwards in the peak of step S703 detecting initial channel frequency response on time domain, to produce peak information.For the initial channel frequency response is adjusted to optimized position, go out best translation information prior to step S704 according to peak information and feedback signal decision-making, and adjust the relative position of initial channel frequency response on frequency domain according to best translation information at step S705.At last, in the numerical value of step S706, carry out the channel estimation of frequency domain dimension, to estimate complete channel frequency response to adjusted initial channel frequency response.About other details of the method, described each embodiment before being included in does not just add narration at this.
What deserves to be mentioned is that channel estimating apparatus and channel estimating and measuring method that above-mentioned each embodiment is listed are applicable to the coherent OFDM system.
In sum, the present invention utilizes peak information to reduce translation optimized search module to reach the calculation times that optimization institute must spend.And the present invention includes the subcarrier channel frequency response in consideration in the computational process that produces decision information.Thus, the present invention not only operating rate have good accuracy soon and also.
Though the present invention discloses as above with preferred embodiment; right its is not in order to limit the present invention; have in the technical field under any and know the knowledgeable usually; without departing from the spirit and scope of the present invention; when can doing a little change and retouching, so protection scope of the present invention is as the criterion when looking the accompanying Claim scope person of defining.
Claims (10)
1. channel estimating apparatus with optimized search, be applicable to demodulating equipment, this demodulating equipment comprises fast Fourier transform unit, translation unit, correcting unit, and signal processing module, this fast Fourier transform unit produces the frequency domain received signal, this demodulating equipment is by this frequency domain received signal, select an output in the output signal of this translation unit and the output signal of this correcting unit with as feedback signal, this channel estimating apparatus is in order to estimate complete channel frequency response and best translation information according to this feedback signal from this frequency domain received signal, wherein this frequency domain received signal comprises that a plurality of symbols are first, each symbol unit comprises scattered pilots data and transmission parameter, and this channel estimating apparatus comprises:
The time shaft channel estimation unit in order to receiving this frequency domain received signal, and according to the formed channel information of those scattered pilots data, is carried out the channel estimation of time dimension, to estimate the initial channel frequency response;
The peak sensing module is in order to detect the peak of this initial channel frequency response on time domain, to export as peak information;
First translation unit is adjusted the relative position of this initial channel frequency response on frequency domain according to this best translation information, and produces the numerical value of adjusting back initial channel frequency response;
Frequency domain axle channel estimation unit in order to this numerical value of adjusting back initial channel frequency response, is carried out the channel estimation of frequency domain dimension, and is obtained this complete channel frequency response; And
Translation optimized search module, produce a plurality of translation information according to this peak information, from those translation information, to utilize this feedback signal and this complete channel frequency response this best translation information of making a strategic decision out, wherein this feedback signal is the output signal of this translation unit in this demodulating equipment or the output signal of this correcting unit, and this translation optimized search module comprises:
The transmission parameter unit provides a plurality of comparison transmission parameters, and those comparison transmission parameters remove corresponding those transmission parameters respectively one to one;
Acquisition unit, in order to the output signal that captures this translation unit in this demodulating equipment or the transmission parameter in the output signal of this correcting unit, and from this complete channel frequency response, capture a plurality of subcarrier channel frequency responses of those transmission parameters of carrying;
Computing unit, those are compared those transmission parameters that transmission parameter, this acquisition unit capture and the numerical value of those subcarrier channel frequency responses carries out computing according to maximum likelihood estimate, producing many result of calculations, and this computing unit obtains and exports decision information from those result of calculations; And
Decision package produces those translation information according to this peak information, and utilizes this decision information to select an output from those translation information, with as this best translation information.
2. the channel estimating apparatus with optimized search as claimed in claim 1, wherein this peak sensing module comprises:
Contrary fast Fourier transform unit is in order to be converted to time domain with this initial channel frequency response; And
The peak sensing unit is in order to detect this peak against the output signal of fast Fourier transform unit, to export as this peak information.
3. the channel estimating apparatus with optimized search as claimed in claim 1, wherein this decision package produces positional information in this best translation information of making a strategic decision out, and this fast Fourier transform unit is judged the computing starting point of the signal that is received according to this positional information.
4. the channel estimating apparatus with optimized search as claimed in claim 1 also comprises:
The channel status evaluation unit estimates channel condition information according to this complete channel frequency response, and wherein this signal processing module carries out the operation of demodulation and decoding according to this channel condition information to the output signal of this correcting unit.
5. channel estimating apparatus with optimized search, be applicable to demodulating equipment, this demodulating equipment comprises fast Fourier transform unit, translation unit, correcting unit, and signal processing module, this fast Fourier transform unit produces the frequency domain received signal, this demodulating equipment is by this frequency domain received signal, select an output in the output signal of this translation unit and the output signal of this correcting unit with as feedback signal, this channel estimating apparatus is in order to estimate complete channel frequency response and best translation information according to this feedback signal from this frequency domain received signal, wherein this frequency domain received signal comprises that a plurality of symbols are first, each symbol unit comprises scattered pilots data and transmission parameter, and this channel estimating apparatus comprises:
The time shaft channel estimation unit in order to receiving this frequency domain received signal, and according to the formed channel information of those scattered pilots data, is carried out the channel estimation of time dimension, to estimate the initial channel frequency response;
The peak sensing module is in order to detect the peak of this initial channel frequency response on time domain, to export as peak information;
First translation unit is adjusted the relative position of this initial channel frequency response on frequency domain according to this best translation information, and produces the numerical value of adjusting back initial channel frequency response;
Frequency domain axle channel estimation unit in order to this numerical value of adjusting back initial channel frequency response, is carried out the channel estimation of frequency domain dimension, and is obtained this complete channel frequency response; And
Translation optimized search module, produce a plurality of translation information according to this peak information, from those translation information, to utilize this feedback signal and this complete channel frequency response this best translation information of making a strategic decision out, wherein this feedback signal is this frequency domain received signal, and this translation optimized search module comprises:
The transmission parameter unit provides a plurality of comparison transmission parameters, and those comparison transmission parameters remove corresponding those transmission parameters respectively one to one;
The acquisition translation unit, in order to acquisition and adjust transmission parameter in this frequency domain received signal, and this acquisition translation unit captures a plurality of subcarrier channel frequency responses that carry those transmission parameters from this complete channel frequency response;
Computing unit, those are compared those transmission parameters that transmission parameter, this acquisition translation unit capture and adjust and the numerical value of those subcarrier channel frequency responses carries out computing according to maximum likelihood estimate, and then produce many result of calculations, and this computing unit obtains and exports decision information from those result of calculations; And
Decision package produces those translation information according to this peak information, and utilizes this decision information to select an output from those translation information, with as this best translation information;
Wherein this acquisition translation unit is adjusted those transmission parameters in this frequency domain received signal according to those translation information.
6. the channel estimating apparatus with optimized search as claimed in claim 5, wherein this decision package produces positional information in this best translation information of making a strategic decision out, and this fast Fourier transform unit is judged the computing starting point of the signal that is received according to this positional information.
7. the channel estimating apparatus with optimized search as claimed in claim 5 also comprises:
The channel status evaluation unit estimates channel condition information according to this complete channel frequency response, and wherein this signal processing module carries out the operation of demodulation and decoding according to this channel condition information to the output signal of this correcting unit.
8. channel estimating and measuring method with optimized search, be applicable to demodulating equipment, this demodulating equipment comprises fast Fourier transform unit, translation unit, correcting unit, and signal processing module, this fast Fourier transform unit produces the frequency domain received signal, this demodulating equipment is from this frequency domain received signal, select an output in the output signal of this translation unit and the output signal of this correcting unit, with as feedback signal, this channel estimating and measuring method is in order to estimate complete channel frequency response and best translation information according to this feedback signal from this frequency domain received signal, this channel estimating and measuring method comprises the following steps:
Receive this frequency domain received signal, this frequency domain received signal comprises that a plurality of symbols are first, and wherein each symbol unit comprises scattered pilots data and transmission parameter;
According to the formed channel information of those scattered pilots data, carry out the channel estimation of time dimension, produce the initial channel frequency response;
Detect the peak of this initial channel frequency response on time domain, to produce peak information;
Go out this best translation information according to this peak information and this feedback signal decision-making, wherein the step that goes out this best translation information according to this peak information and this feedback signal decision-making comprises:
Produce a plurality of translation information according to this peak information;
Adjust the relative position of this initial channel frequency response on frequency domain one by one according to each those translation information, and, carry out the channel estimation of frequency domain dimension, to estimate this complete channel frequency response to the numerical value of adjusted those initial channel frequency responses;
When this feedback signal is the output signal of this translation unit in this demodulating equipment or the output signal of this correcting unit, from this feedback signal, capture transmission parameter, and from this complete channel frequency response, capture the carrying those transmission parameters a plurality of subcarrier channel frequency responses, and the numerical value of a plurality of comparison transmission parameters, those transmission parameters that captured and those subcarrier channel frequency responses is carried out computing according to maximum likelihood estimate, producing many first result of calculations, and from those first result of calculations, obtain decision information;
And when this feedback signal is this frequency domain received signal, capture and adjust the transmission parameter in this feedback signal, and from this complete channel frequency response, capture the carrying those transmission parameters those subcarrier channel frequency responses, and according to maximum likelihood estimate those are compared transmission parameter, those transmission parameters that capture and adjust and the numerical value of those subcarrier channel frequency responses and carry out computing, producing many second result of calculations, and from those second result of calculations, obtain this decision information; And
Utilize this decision information from those translation information, to select one as this best translation information;
Adjust the relative position of this initial channel frequency response on frequency domain according to this best translation information; And
To the numerical value of adjusted this initial channel frequency response, carry out the channel estimation of frequency domain dimension, to estimate this complete channel frequency response.
9. the channel estimating and measuring method with optimized search as claimed in claim 8 also comprises:
Produce positional information in this best translation information of making a strategic decision out, this fast Fourier transform unit is judged the computing starting point of the signal that is received according to this positional information.
10. the channel estimating and measuring method with optimized search as claimed in claim 8 also comprises:
Estimate channel condition information according to this complete channel frequency response, this signal processing module carries out the operation of demodulation and decoding according to this channel condition information to the output signal of this correcting unit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2006101393681A CN101155155B (en) | 2006-09-25 | 2006-09-25 | Channel estimating device with optimized search and method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2006101393681A CN101155155B (en) | 2006-09-25 | 2006-09-25 | Channel estimating device with optimized search and method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN101155155A CN101155155A (en) | 2008-04-02 |
| CN101155155B true CN101155155B (en) | 2010-11-10 |
Family
ID=39256595
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2006101393681A Expired - Fee Related CN101155155B (en) | 2006-09-25 | 2006-09-25 | Channel estimating device with optimized search and method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN101155155B (en) |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1463151A (en) * | 2002-05-28 | 2003-12-24 | 三星电子株式会社 | Orthogonal frequency-division multiplying equilizer for actuating adaptive balance according to channel state |
| CN1620052A (en) * | 2003-11-19 | 2005-05-25 | 松下电器产业株式会社 | OFDM reception apparatus |
-
2006
- 2006-09-25 CN CN2006101393681A patent/CN101155155B/en not_active Expired - Fee Related
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1463151A (en) * | 2002-05-28 | 2003-12-24 | 三星电子株式会社 | Orthogonal frequency-division multiplying equilizer for actuating adaptive balance according to channel state |
| CN1620052A (en) * | 2003-11-19 | 2005-05-25 | 松下电器产业株式会社 | OFDM reception apparatus |
Also Published As
| Publication number | Publication date |
|---|---|
| CN101155155A (en) | 2008-04-02 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN100574303C (en) | Method that signal sequence is synchronous and synchronous circuit | |
| US7027429B2 (en) | Method and apparatus for time and frequency synchronization of OFDM communication systems | |
| CN101981879B (en) | Broadband pilot channel estimation using a reduced order FFT and a hardware interpolator | |
| CN101116270B (en) | Digital broadcast receiving apparatus having transmission path estimating ability | |
| US7936844B2 (en) | Channel estimation apparatus with the optimal search and method thereof | |
| CN107257324B (en) | Time-frequency joint synchronization method and device in OFDM system | |
| CN101909024B (en) | Method and device for estimating maximum Doppler frequency offset | |
| JP5565165B2 (en) | OFDM communication receiver | |
| CN115086114B (en) | Channel estimation method based on distributed placement of orthogonal time-frequency space OTFS pilot frequency | |
| KR100896654B1 (en) | Apparatus and method for estimating delay spread of multi-path fading channel in ofdm system | |
| WO2022088564A1 (en) | Motion platform-based multi-carrier underwater acoustic communication doppler estimation and compensation method | |
| CN100355222C (en) | Apparatus and method for estimating a velocity of a mobile terminal in a mobile communication system | |
| CN100544338C (en) | Be used for detecting the equipment and the method for echo at frequency domain | |
| CN101741775B (en) | Taylor expansion-based single-frequency OFDM time-varying channel estimation method | |
| US8923456B2 (en) | Method and system for channel estimation | |
| US20100046359A1 (en) | Wireless Terminal, Base Station and Channel Characteristic Estimating Method | |
| CN101895309A (en) | Signal to noise ratio estimation-based frequency offset regulation method | |
| CN101155155B (en) | Channel estimating device with optimized search and method thereof | |
| CN116405357A (en) | Carrier frequency offset estimation compensation method for Fresnel domain zero pilot frequency OCDM underwater acoustic communication | |
| CN101360084A (en) | Inter-carrier interference eliminating method, apparatus, signal receiving method and receiver | |
| CN103338166A (en) | Improved channel estimation method | |
| JP4287686B2 (en) | Multi-carrier receiver and line compensation method | |
| CN109981516B (en) | Data receiving method, device and equipment of multi-carrier system and readable storage medium | |
| CN102045290A (en) | Gray modeling-based OFDM narrow-band slow-fading slowly time-varying channel estimation method | |
| CN114978839B (en) | Non-uniform Doppler estimation method and system in underwater acoustic communication |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20101110 Termination date: 20170925 |
|
| CF01 | Termination of patent right due to non-payment of annual fee |