CN101741771B - Channel estimation method and device - Google Patents

Abstract

The invention discloses channel estimation method and device. The device comprises a control module, a scattered pilot extracting module, a time domain interpolation module and an FIR (Finite Impulse Response) filter module, wherein the control module is used for storing input OFDM (Orthogonal Frequency Division Multiplexing) symbol data into an OFDM data buffer area of a channel estimating device; the scattered pilot extracting module is used for storing the scattered pilot of each OFDM symbol data, which is obtained from the OFDM symbol data stored in the OFDM data buffer area; the time domain interpolation module is used for reading the scattered pilot of the adjacent OFDM symbol from a scattered pilot buffer area and storing the scattered pilot after carrying out time domain linear interpolation processing into the scattered pilot buffer area; and the FIR filter module is used for obtaining a filter coefficient from a filter coefficient buffer area, obtaining the scattered pilot after time domain linear interpolation processing from the scattered pilot buffer area, carrying out FIR filter calculation according to the obtained filter coefficient and the scattered pilot and outputting a channel estimating result. The invention can favorably meet the requirement of the CMMB (China Mobile Multimedia Broadcasting) standard channel estimation processing function.

Description

Channel estimation methods and device

Technical field

The present invention relates to the communications field, in particular to a kind of channel estimation methods and device.

Background technology

China Mobile's DMB (China Mobile MultimediaBroadcasting, referred to as CMMB) system be utilize high-power S-band satellite-signal cover nationwide, utilize ground supplement translator with frequently simultaneously with content repeater satellite signal, mend point and cover the satellite-signal blind area, utilize mobile radio networks to build return path, form the mobile media broadcasting network that One-to-All Broadcast and two-way interactive combine.

The broadcast channel physical layer bandwidth of CMMB standard definition comprises 8MHz and two kinds of options of 2MHz.Physical layer signal was 1 frame in every 1 second, was divided into 40 time slots.The length of each time slot is 25ms, comprises 1 beacon and 53 OFDMs (OrthogonalFrequency Division Multiplexing is referred to as OFDM) symbol.

The formation of frequency-domain OFDM symbol be by with data subcarrier and scattered pilot with continuous pilot multiple connection be in the same place, form the OFDM frequency domain symbol, wherein, each OFDM symbol comprises Nv effectively subcarrier, under the 8MHz pattern, the value of Nv is 3076.

Record in each time slot on n OFDM symbol i effectively subcarrier be Xn (i), i=0,1 ..., Nv-1; 0≤n≤52.Fig. 1 is the schematic diagram of data subcarrier, scattered pilot and the continuous pilot method of salary distribution according to correlation technique, and the effective subcarrier that shows the OFDM symbol as Fig. 1 is assigned as the method for salary distribution of data subcarrier, scattered pilot and continuous pilot.

Continuous pilot is to transmit the subcarrier of identical information on each OFDM symbol of same time slot.When Bf=8MHz, each OFDM symbol comprises 82 continuous pilot.The position of continuous pilot in the OFDM symbol is as shown in table 1.

Under table 1 8MHz pattern, the position of continuous pilot in the OFDM symbol

	Bf＝8MHz
		Continuous pilot	0，22，78，92，168，174，244，274，278， 344，382，424，426，496，500，564，608，650， 688，712，740，772，846，848，932，942，950， 980，1012，1066，1126，1158，1214，1244，1276，1280，1326，1378，1408，1508，1537，1538， 1566，1666，1736，1748，1794，1798，1830， 1860，1916，1948，2008，2062，2094，2124， 2132，2142，2226，2228，2302，2334，2362， 2386，2424，2466，2510，2574，2578，2648， 2650，2692，2730，2796，2800，2830，2900， 2906，2982，2996，3052，3075

Each continuous pilot adopts binary phase shift keying (Binary Phase Shift Key, referred to as BPSK) modulation system transmission 1 bit information, the BPSK modulation system as shown in Figure 2, wherein, partial continuous pilot tone (position sees Table 2) is used for transmitting 16 bit transfer indication informations, and all the other continuous pilot transmit fixed bit " 0 ".

Be used for the position of the continuous pilot of system information under table 2 8MHz pattern

Bit	Bf＝8MHz
		0	22、650、1860、2466
1	78、688、1916、2510
		2	92、712、1948、2574
3	168、740、2008、2578
		4	174、772、2062、2648
5	244、846、2094、2650
		6	274、848、2124、2692
7	278、932、2132、2730
		8	344、942、2142、2796
9	382、950、2226、2800
		10	424、980、2228、2830

11	426、1012、2302、2900
		12	496、1066、2334、2906
13	500、1126、2362、2982
		14	564、1158、2386、2996
15	608、1214、2424、3052

Scattered pilot sends known symbol 1+0j, and effective subcarrier number m value rule that in each time slot, in the 1st OFDM symbol, scattered pilot is corresponding is as follows:

Bf＝8MHz：

if(mod(1，2)＝＝0)

$m=\left\{\begin{array}{cc}8p+1,& p=\mathrm{0,1,2},...,191\\ 8p+3,& p=\mathrm{192,193,194},...,383\end{array}\right.$

if(mod(1，2)＝＝1)

$m=\left\{\begin{array}{cc}8p+5,& p=\mathrm{0,1,2},...,191\\ 8p+7,& p=\mathrm{192,193,194},...,383\end{array}\right.$

Have the series of complex phenomenons such as multipath, Doppler effect, Noise and Interference due to channel, therefore, when receiving the CMMB signal, in order to guarantee the quality of reception, channel estimating just becomes an indispensable processing procedure.

In correlation technique, for channel estimating, following several method is arranged generally:

(1) ratio method, this method realizes simple, but noise inhibiting ability is poor.

(2) linear minimum mean square error (Linear Minimum Mean Square Error is referred to as LMMSE) method, this method has noise suppressed preferably, but needs the statistical property of channel and noise, realizes complicated.

(3) time domain correlation, this method has noise suppressed preferably, but operand is larger.

Therefore, because there is defects in present channel estimation methods, can not satisfy the CMMB system to needs simple in structure, low in resources consumption, that realize the performance such as easy.

Summary of the invention

The defective that exists for present channel estimation methods can not satisfy the CMMB system problem of needs simple in structure, low in resources consumption, as to realize the performance such as easy is proposed the present invention, for this reason, the present invention aims to provide a kind of channel estimation methods and device, to address the above problem.

According to an aspect of the present invention, provide a kind of channel estimating apparatus.

Channel estimating apparatus according to the present invention comprises: control module, and the orthogonal frequency division multiplex OFDM symbol data that is used for inputting stores the OFDM data buffer zone of channel estimating apparatus into; The scattered pilot extraction module is used for obtaining the scattered pilot of each OFDM symbol data from the OFDM symbol data of OFDM data buffer area storage, and the scattered pilot that obtains is stored into the scattered pilot buffering area of channel estimating apparatus; The time domain interpolation module for read the scattered pilot of adjacent OFDM symbol from the scattered pilot buffering area, carry out the time domain linear interpolation processing, and the scattered pilot that will carry out after the time domain linear interpolation processing stores the scattered pilot buffering area into; Limit for length's impulse response FIR filtration module is arranged, be used for obtaining filter factor from the filter coefficient buffering area of channel estimating apparatus, obtain scattered pilot after the time domain linear interpolation processing from the scattered pilot buffering area, carry out FIR filtering according to the filter factor that obtains and scattered pilot and calculate and the delivery channel estimated result.

Preferably, control module also is used for scheduling scattered pilot extraction module, time domain interpolation module, FIR filtration module, OFDM data buffer area, scattered pilot buffering area, filter coefficient buffering area.

Preferably, the OFDM data buffer zone comprises two random access memory rams.

Preferably, the OFDM data buffer zone is used for carrying out when the OFDM symbol data is stored ping-pong operation.

Preferably, the scattered pilot extraction module is used for directly extracting scattered pilot or converting the continuous pilot the OFDM symbol data of OFDM data buffer area storage to scattered pilot from the OFDM symbol data of OFDM data buffer area storage.

Preferably, the scattered pilot buffering area comprises three block RAMs.

Preferably, the filter coefficient buffering area comprises for according to time slot, the filter factor of input being carried out up/down two and half district of ping-pong operation.

According to an aspect of the present invention, provide a kind of channel estimation methods.

According to channel estimation methods of the present invention, be applied to China Mobile's digital multimedia broadcasting system, comprise the steps: to obtain the scattered pilot of the adjacent OFDM symbol of current OFDM symbol from OFDM input data, and scattered pilot is carried out the time domain linear interpolation processing; Carry out filtering according to the scattered pilot after the time domain linear interpolation processing and the filter factor that obtains and calculate, obtain channel estimation results.

Preferably, inputting from OFDM the scattered pilot that obtains the adjacent OFDM symbol of current OFDM symbol data comprises: directly extract the scattered pilot of the adjacent OFDM symbol of current OFDM symbol from OFDM input data; The continuous pilot of OFDM being inputted the adjacent OFDM symbol of current OFDM symbol in data converts scattered pilot to.

Preferably, scattered pilot being carried out the time domain linear interpolation processing comprises: the scattered pilot of the adjacent OFDM symbol of current OFDM symbol is carried out arithmetic average.

Preferably, before carrying out filtering calculating, said method also comprises: the subcarrier between two adjacent discrete pilot tones of same OFDM symbol is carried out zero insertion process.

by the present invention, control module in channel estimating apparatus is saved to the OFDM data buffer zone with it after receiving OFDM input data, then extract the scattered pilot of this symbol, and the startup interpolating module carries out time domain interpolation, dispatching at last the FIR filtration module calculates and the delivery channel estimated result, solve defective that present channel estimation methods exists and can not satisfy the CMMB system to simple in structure, low in resources consumption, realize the problem of the needs of the performance such as easy, apparatus structure provided by the invention is simple, the hardware resource service efficiency is high and be easy to realize, can satisfy well the CMMB standard channel and estimate the needs of processing capacity.

Description of drawings

Accompanying drawing described herein is used to provide a further understanding of the present invention, consists of the application's a part, and illustrative examples of the present invention and explanation thereof are used for explaining the present invention, do not consist of improper restriction of the present invention.In the accompanying drawings:

Fig. 1 is the schematic diagram of data subcarrier, scattered pilot and the continuous pilot method of salary distribution according to correlation technique;

Fig. 2 is the schematic diagram according to the BPSK constellation mapping of correlation technique;

Fig. 3 is the structured flowchart according to the channel estimating apparatus of the embodiment of the present invention;

Fig. 4 is the schematic diagram according to the channel estimation works flow process of the embodiment of the present invention;

Fig. 5 is the OFDM0 buffering area use schematic diagram according to the embodiment of the present invention;

Fig. 6 is the OFDM1 buffering area use schematic diagram according to the embodiment of the present invention;

Fig. 7 is the OFDM51 buffering area use schematic diagram according to the embodiment of the present invention;

Fig. 8 is the OFDM52 buffering area use schematic diagram according to the embodiment of the present invention;

Fig. 9 is the schematic diagram according to the FIR filter construction of the embodiment of the present invention;

Figure 10 is the flow chart according to the channel estimation methods of the embodiment of the present invention.

Embodiment

Functional overview

consider that defective that present channel estimation methods exists can not satisfy the CMMB system to simple in structure, low in resources consumption, realize the problem of the needs of the performance such as easy, the embodiment of the present invention provides a kind of channel estimation methods and device, can be applied to the pattern of CMMB standard 8MHz bandwidth, determine channel estimating according to scattered pilot information known in signal transmission, in above-mentioned channel estimating apparatus, control module is saved to the OFDM data buffer zone with it after receiving OFDM input data, then extract the scattered pilot of this symbol, and the startup interpolating module carries out time domain interpolation, dispatching at last the FIR filtration module calculates and the delivery channel estimated result.

Need to prove, in the situation that do not conflict, embodiment and the feature in embodiment in the application can make up mutually.Describe below with reference to the accompanying drawings and in conjunction with the embodiments the present invention in detail.

Device embodiment

According to embodiments of the invention, a kind of channel estimating apparatus is provided, this device is used for realizing the channel estimating of CMMB standard.Fig. 3 is the structured flowchart according to the channel estimating apparatus of the embodiment of the present invention, as shown in Figure 3, this device comprises: control module 2, scattered pilot extraction module 4, time domain interpolation module 6, limit for length's impulse response (Finite ImpulseResponse is referred to as FIR) filtration module 8 is arranged, and the below is described said structure.Control module 2, the OFDM symbol data that is used for inputting stores the OFDM data buffer zone of channel estimating apparatus into; Control module 2 also is used for each module of this channel estimating apparatus of scheduling, includes but not limited to lower module: scattered pilot extraction module, time domain interpolation module, FIR filtration module, OFDM data buffer area, scattered pilot buffering area, filter coefficient buffering area.

Scattered pilot extraction module 4 is used for obtaining the scattered pilot of each OFDM symbol data from the OFDM symbol data of OFDM data buffer area storage, and the scattered pilot that obtains is stored into the scattered pilot buffering area of channel estimating apparatus;

Particularly, scattered pilot extraction module 4 scattered pilot that obtains each OFDM symbol data comprises following dual mode:

(1) directly extract scattered pilot from the OFDM symbol data of OFDM data buffer area storage.

(2) convert the continuous pilot in the OFDM symbol data of OFDM data buffer area storage to scattered pilot.

Time domain interpolation module 6 for read the scattered pilot of adjacent OFDM symbol from the scattered pilot buffering area, carry out the time domain linear interpolation processing, and the scattered pilot that will carry out after the time domain linear interpolation processing stores the scattered pilot buffering area into.

FIR filtration module 8, be used for obtaining filter factor from the filter coefficient buffering area of channel estimating apparatus, obtain scattered pilot after (reading) time domain linear interpolation processing from the scattered pilot buffering area, carry out FIR filtering according to the filter factor that obtains and scattered pilot and calculate and the delivery channel estimated result.

This channel estimating apparatus also comprises following buffering area: OFDM data buffer zone 1, scattered pilot buffering area 3, filter coefficient buffering area 5, the below is described each buffering area.

OFDM data buffer zone 1 comprises two random asccess memory (Random AccessMemory is referred to as RAM), carries out ping-pong operation when according to the scheduling of control module, the OFDM symbol data being stored.

Scattered pilot buffering area 3 comprises 3 block RAMs, and this 3 block RAM structure is consistent, recycles, and every block RAM is preserved this symbol scattered pilot, and the average of adjacent-symbol scattered pilot.

Filter coefficient buffering area 5, that is, a block RAM is divided into up/down two and half district, according to time slot, the filter factor of input is carried out ping-pong operation, and preserves the filter factor of this time slot.

In addition, this channel estimating apparatus can also comprise: top-level module 0, be responsible for integrated input/output interface, inner each module and the RAM of this device.

The below is described in conjunction with the implementation procedure of above-mentioned channel estimating apparatus to the embodiment of the present invention for the pattern of CMMB standard 8MHz bandwidth.

Fig. 4 is the schematic diagram according to the channel estimation works flow process of the embodiment of the present invention, and as shown in Figure 4, system enters IDLE (free time) 0 state after receiving the reset reset signal; If receive the start enabling signal, enter SAVE (that is, the storage of OFDM symbol data) 1 state, otherwise continue to keep idle condition.

After entering the SAVE state, an OFDM symbol data of inputting is saved in the OFDM data buffer zone, the SAVE state finishes to enter PEXT (scattered pilot extraction) 2 states after (save_over).

After entering the PEXT state, extract the scattered pilot of current sign and deposit the scattered pilot buffering area in, then convert continuous pilot subcarrier 1537,3075 to scattered pilot, deposit in the lump the scattered pilot buffering area in.If current is the scattered pilot that extracts OFDM0, owing to there is no the OFDM1 data, can not carry out the time domain linear interpolation according to the scattered pilot of adjacent-symbol, so the PEXT state turns back to the IDLE state after finishing; Otherwise the PEXT state finishes to transfer to PINS (time domain interpolation) 3 states after (pext_over).

After entering the PINS state, according to the average of adjacent-symbol scattered pilot, carry out the time domain linear interpolation, obtain the input of 4 times of interpolation FIR filters of this symbol, the PINS state enters FILT (filtering) 4 states after completing (pins_over).

After entering the FILT state, read scattered pilot and filter coefficient after linear interpolation, carry out FIR filtering and calculate, the channel estimation results after output is calculated.If current after filtering finishes is that OFDM51 is carried out filtering, because OFDM52 time domain linear interpolation need to be OFDM51 as adjacent-symbol, so need to transfer to the PEXT state, again extract the scattered pilot of OFDM51 and cover the deposit position of scattered pilot buffering area OFDM50; Otherwise return to the IDLE idle condition.

The OFDM data buffer zone is comprised of two block RAMs, carries out ping-pong operation, preserves indicator register ofdm_save_num by data and indicates that current is the input data of preserving which OFDM symbol.The scattered pilot buffering area is comprised of 3 block RAMs, recycles, and extracts indicator register ofdm_pext_num by scattered pilot and determines that current is the scattered pilot that extracts which OFDM symbol.Describe the occupation mode of buffering area in detail below with reference to Fig. 5, Fig. 6, Fig. 7 and Fig. 8.

Fig. 5 is the OFDM0 buffering area use schematic diagram according to the embodiment of the present invention, as shown in Figure 5, after first symbol OFDM 0 data of time slot are preserved, starting scattered pilot extracts, after having extracted the scattered pilot of OFDM0, so also do not have the scattered pilot of adjacent-symbol at this moment can't carry out filtering due to current, control module turns back to idle condition and waits for next symbol initial signal.

Fig. 6 is the OFDM1 buffering area use schematic diagram according to the embodiment of the present invention, as shown in Figure 6, when extracting the scattered pilot of OFDM1, it need to be write simultaneously scattered pilot buffer RAM piece buffer b and buffer c, like this follow-up when carrying out the time domain linear interpolation, can directly use interpolating module to complete time domain linear interpolation to OFDM0.

Fig. 7 uses schematic diagram according to the OFDM51 buffering area of the embodiment of the present invention, as shown in Figure 7, after the scattered pilot that extracts OFDM52, asks for the scattered pilot average of OFDM50 and OFDM52 and is inserted into the scattered pilot buffer RAM of OFDM51.

Fig. 8 is the OFDM52 buffering area use schematic diagram according to the embodiment of the present invention, as shown in Figure 8, after end is calculated in OFDM51 filtering, control module turns back to scattered pilot and extracts state, again extract the scattered pilot of OFDM51 and store buffer c into, then carry out the filtering input that the time domain linear interpolation obtains OFDM52.

Fig. 9 is the schematic diagram according to the FIR filter construction of the embodiment of the present invention, as shown in Figure 9, in order to save hardware resource, the FIR filter adopts flowing structure, I, the multiplexing complex multiplier of Q two paths of data, accumulator is responsible for each complex multiplication result is added up, the channel estimation results after last output saturation is processed.

Can find out according to the scattered pilot location formula, if export the channel estimation results of all subcarriers, need to carry out the judgement of four kinds of situations for the scattered pilot subcarrier when follow-up solution is shone upon.According to table 2 as can be known, numbering 0,1537,1538,3075 these four continuous pilot do not comprise system information, if remove this four continuous pilot during channel estimating output, effective subcarrier number m value rule that in each time slot, the scattered pilot of n OFDM symbol is corresponding is reduced to:

ifmod(n，2)＝＝0

m＝8p

ifmod(n，2)＝＝1

m＝8p+4

Based on above-mentioned consideration, for each OFDM symbol, only export 1～1536 and 1539～3074 channel estimation results of totally 3072 subcarriers, can simplify like this difficulty and the saving resource of subsequent treatment.

Embodiment of the method

According to embodiments of the invention, a kind of channel estimation methods is provided, be applied to the CMMB system, the method can realize in conjunction with above-mentioned channel estimating apparatus.Figure 10 is the flow chart according to the channel estimation methods of the embodiment of the present invention, and as shown in figure 10, the method comprises following step S102 and step S104, and concrete operations are as follows:

Step S102 obtains the scattered pilot of the adjacent OFDM symbol of current OFDM symbol, and scattered pilot is carried out the time domain linear interpolation processing from OFDM input data; The time domain linear interpolation processing here refers to the scattered pilot of the adjacent OFDM symbol of current OFDM symbol is carried out arithmetic average.

Wherein, input from OFDM the scattered pilot that obtains the adjacent OFDM symbol of current OFDM symbol data and comprise following dual mode:

(1) directly extract the scattered pilot of the adjacent OFDM symbol of current OFDM symbol from OFDM input data.

(2) continuous pilot of OFDM being inputted the adjacent OFDM symbol of current OFDM symbol in data converts scattered pilot to.

Step S104 carries out filtering according to the scattered pilot after the time domain linear interpolation processing and the filter factor that obtains and calculates, and obtains channel estimation results; Before carrying out filtering calculating, need to carry out to the subcarrier between two adjacent discrete pilot tones of same OFDM symbol zero insertion and process.

By this embodiment, according to the scattered pilot of current OFDM symbol, use its adjacent OFDM symbol scattered pilot to carry out linear interpolation in time domain, adopt 4 times of interpolations, the variable FIR filters of coefficient to realize the channel estimating of CMMB system at frequency domain.

Below in conjunction with example to realizing that the implementation procedure of channel estimating is described under CMMB standard 8MHz bandwidth mode.

At first, convert continuous pilot subcarrier 1537 and 3075 to scattered pilot;

${\mathrm{HP}}_l\left(k\right)=C_l\left(k\right)\·\frac{\sqrt{2}}{2}(1-j)$ k＝1037，3075

Then scattered pilot is carried out time domain interpolation, particularly, utilize the scattered pilot of former and later two OFDM symbols carry out arithmetic average obtain current sign the time domain interpolation result (that is, above-mentioned step S102) at corresponding subcarrier place;

HP _l(k)＝(HP _l-1(k)+HP _l+1(k))/2

K value rule is as follows:

if(mod(1，2)＝＝0)

$k=\left\{\begin{array}{ccc}8p+5,& p=\mathrm{0,1,2},...,191& 0\≤k\≤1537\\ 8p+1543,& p=\mathrm{0,1,2},...,191& 1538\≤k\≤3075\end{array}\right.$

if(mod(1，2)＝＝1)

$k=\left\{\begin{array}{ccc}8p+1,& p=\mathrm{0,1,2},...,191& 0\≤k\≤1537\\ 8p+1540,& p=\mathrm{0,1,2},...,191& 1538\≤k\≤3075\end{array}\right.$

Through after time domain interpolation, the interval in OFDM symbol between former and later two adjacent pilot frequencies is 4 subcarriers, it is carried out 4 times of zero insertions process and obtain HP _l(m);

if(0≤m≤1537)

${\mathrm{HP}}_l\left(m\right)=\left\{\begin{array}{cc}{\mathrm{HP}}_l\left(k\right),& m=4k+1\\ 0,& m\≠4k+1\end{array}\right.$

if(1538≤m≤3075)

${\mathrm{HP}}_l\left(m\right)=\left\{\begin{array}{cc}{\mathrm{HP}}_l\left(k\right),& m=4k+1539\\ 0,& m\≠4k+1539\end{array}\right.$

Then to HP _l(m) carrying out filter factor is that the FIR filtering of Coef (n) is processed, and can obtain the channel estimation results after interpolation

(that is, above-mentioned step S104).

$\widehat{{\mathrm{HP}}_l\left(m\right)}=\underset{n=1}{\overset{q}{\mathrm{\Σ}}}\mathrm{Coef}\left(n\right)\·{\mathrm{HP}}_l(m-n)$

By the above embodiment of the present invention, the channel estimation methods of time domain linear interpolation, frequency domain interpolation filtering has been proposed, it is realized simple and can satisfy the needs of CMMB system on performance.Recycling of the ping-pong operation of OFDM data buffer zone and scattered pilot buffering area saved the expense of hardware RAM resource effectively.Filter coefficient take time slot as unit is kept at special-purpose RAM in, can according to the actual state of channel, adjust neatly performance of filter like this.The FIR filter adopts pipeline mode, and multiplexing multiplier has been saved hardware resource.Remove four useless continuous pilot during the delivery channel estimated result, simplified follow-up solution mapping and processed.In sum, channel estimation methods provided by the invention and apparatus structure are simple, and the hardware resource service efficiency is high and be easy to realization, can satisfy well the needs that the CMMB standard channel is estimated processing capacity.

obviously, those skilled in the art should be understood that, above-mentioned each module of the present invention or each step can realize with general calculation element, they can concentrate on single calculation element, perhaps be distributed on the network that a plurality of calculation elements form, alternatively, they can be realized with the executable program code of calculation element, thereby, they can be stored in storage device and be carried out by calculation element, perhaps they are made into respectively each integrated circuit modules, perhaps a plurality of modules in them or step being made into the single integrated circuit module realizes.Like this, the present invention is not restricted to any specific hardware and software combination.

The above is only the preferred embodiments of the present invention, is not limited to the present invention, and for a person skilled in the art, the present invention can have various modifications and variations.Within the spirit and principles in the present invention all, any modification of doing, be equal to replacement, improvement etc., within all should being included in protection scope of the present invention.

Claims (7)

1. a channel estimating apparatus, is characterized in that, comprising:

Control module, the orthogonal frequency division multiplex OFDM symbol data that is used for inputting stores the OFDM data buffer zone of described channel estimating apparatus into;

The scattered pilot extraction module be used for obtaining the scattered pilot of each OFDM symbol data from the described OFDM symbol data of described OFDM data buffer area storage, and the described scattered pilot that will obtain stores the scattered pilot buffering area of described channel estimating apparatus into;

The time domain interpolation module for read the scattered pilot of adjacent OFDM symbol from described scattered pilot buffering area, carry out the time domain linear interpolation processing, and the scattered pilot that will carry out after the time domain linear interpolation processing stores described scattered pilot buffering area into;

Limit for length's impulse response FIR filtration module is arranged, be used for obtaining filter factor from the filter coefficient buffering area of described channel estimating apparatus, obtain scattered pilot after described time domain linear interpolation processing from described scattered pilot buffering area, carry out FIR filtering according to the described filter factor that obtains and described scattered pilot and calculate and the delivery channel estimated result.

2. device according to claim 1, it is characterized in that, described control module also is used for dispatching described scattered pilot extraction module, described time domain interpolation module, described FIR filtration module, described OFDM data buffer area, described scattered pilot buffering area, described filter coefficient buffering area.

3. device according to claim 1, is characterized in that, described OFDM data buffer zone comprises two random access memory rams.

4. device according to claim 1, is characterized in that, carries out ping-pong operation when described OFDM data buffer zone is used for described OFDM symbol data storage.

5. device according to claim 1, it is characterized in that, described scattered pilot extraction module is used for directly extracting scattered pilot or converting the continuous pilot the described OFDM symbol data of described OFDM data buffer area storage to scattered pilot from the described OFDM symbol data of described OFDM data buffer area storage.

6. device according to claim 1, is characterized in that, described scattered pilot buffering area comprises three block RAMs.

7. device according to claim 1, is characterized in that, described filter coefficient buffering area comprises for according to time slot, the filter factor of input being carried out up/down two and half district of ping-pong operation.

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