CN102185803B - Channel estimation method under high-speed mobile environment - Google Patents

Abstract

The invention discloses a channel estimation method under a high-speed mobile environment, and is characterized in that a channel estimation method based on a base extension model is utilized to obtain channel estimation values at pilot frequency character positions; then optimal time-domain interpolation coefficients at the pilot frequency character positions corresponding to the channel estimation method based on the base extension model are calculated; and finally the obtained channel estimation values at the pilot frequency character positions multiplies the obtained optimal time-domain interpolation coefficients to obtain channel estimation values at data character positions. In the method, the exact channel estimation values at the pilot frequency character positions are combined with the optimal time-domain interpolation coefficients by the calculation so as to exactly estimate the channel estimation values at the data character position under the high-speed mobile environment, thus the channel estimation accuracy is obviously improved by using the channel estimation method provided by the invention under the high-speed mobile environment compared with an existing channel estimation method. The channel estimation method provided by the invention is applied to carrying out the channel estimation on wireless mobile communication systems using starlike pilot frequency patterns or block pilot frequency patterns frame signals under the high-speed mobile environment.

Description

Channel estimation methods under a kind of high-speed mobile environment

Technical field

The present invention relates to the wireless mobile communications field, particularly channel estimation methods wherein.

Background technology

Along with the construction energetically of high-speed railway all over the world, wireless mobile telecommunication technology under high-speed mobile environment (120 kilometers/hour, 350 kilometers/hour or higher) proper communication be urgent problem, be applicable to that wherein the high accuracy channel estimation methods under this high-speed mobile environment is the difficult point that needs to be resolved hurrily.For transmission rate and the availability of frequency spectrum that improves mobile radio system, the user can be assigned with the subcarrier of some in interior all subcarriers of mobile radio system frame signal in order to communication.The research of present different translational speed environment lower channel methods of estimation mainly concentrates on the channel estimation methods based on pilot sub-carrier, this method at first utilizes the pilot sub-carrier of distributing to the user in the frequency pilot sign to obtain distributing in the frequency pilot sign channel estimation value of user's pilot sub-carrier position, carry out the interpolation channel estimating of frequency domain and time-domain direction then respectively, thus obtain in the frequency pilot sign and data symbol in distribute to the channel estimation value at all sub-carrier positions places of user.

The typical frame signal of mobile radio system as depicted in figs. 1 and 2, Fig. 1 is called the frame signal of starlike pilot frequency design, Fig. 2 is called the frame signal of block pilot frequency design, a symbol is shown in a tabulation among Fig. 1 and Fig. 2, as an OFDM (OFDM, Orthogonal Frequency Division Multiplexing) symbol, a symbol is made up of several subcarriers, the black blockage is represented pilot sub-carrier, the white blockage is represented data subcarrier, the symbol that contains pilot sub-carrier among Fig. 1 and Fig. 2 is called frequency pilot sign, and all subcarriers all are that the symbol of data subcarrier is called data symbol.Note time-domain d treats k data sub-carrier positions of data estimator symbol place channel estimation value in the place

K=N _{U, s}, N _{U, s}+ 1 ..., N _{U, e}The channel estimation value at M corresponding pilot frequency symbol position place is p in the position of time-domain _i, i=1,2..., M makes the column vector of the channel estimation value composition at this M k sub-carrier positions place of frequency pilot sign be

K=N _{U, s}, N _{U, s}+ 1 ..., N _{U, e}, N wherein _{U, s}Represent to distribute in a frequency pilot sign or the data symbol user's subcarrier original position, N _{U, e}Represent to distribute in a frequency pilot sign or the data symbol user's subcarrier end position,

The estimated value of expression " * ", " [] ^T" the transposition computing of expression " [] ".Then time-domain d treats at the place k data sub-carrier positions of data estimator symbol place channel estimation value

K=N _{U, s}, N _{U, s}+ 1 ..., N _{U, e}Can by

Interpolation draws, and makes this time-domain interpolation coefficient be Be that a size is the row vector of 1 * M, then time-domain d treats at the place k data sub-carrier positions of data estimator symbol place channel estimation value

K=N _{U, s}, N _{U, s}+ 1 ..., N _{U, e}

Existing high-speed mobile environment lower channel method of estimation is mainly used based on least square (LS, least squares) method estimates the channel estimation value (or this channel estimation value is carried out further various transform domain filtering handle) of the pilot sub-carrier position of distributing to the user in the frequency pilot sign, carry out the interpolation channel estimating of frequency domain direction then, obtain distributing in the frequency pilot sign channel estimation value at all sub-carrier positions places of user, carry out the interpolation channel estimating of time-domain direction at last, thereby estimate the channel estimation value at all sub-carrier positions places that distribute to the user in the data symbol.The shortcoming of this method is: (1) this method assumed wireless channel is static constant in a symbol period, but wireless channel changes fast under high-speed mobile environment, wireless channel is that static constant hypothesis is no longer set up in a symbol period, thereby the precision of channel estimation that causes distributing to user's pilot sub-carrier position based on the method for LS in frequency pilot sign descends; (2) owing in frequency pilot sign, distribute to the precision of channel estimation decline of user's pilot sub-carrier position based on the method for LS, thereby the precision of channel estimation that causes distributing to user's data sub-carrier positions place in the resulting frequency pilot sign of interpolation channel estimating of frequency domain direction descends, and then the precision of channel estimation that causes distributing in the frequency pilot sign under the high-speed mobile environment all sub-carrier positions places of user descends; (3) owing to distribute to the precision of channel estimation at all sub-carrier positions places of user in the frequency pilot sign and descend, the precision of channel estimation that causes at last distributing to all sub-carrier positions places of user in the resulting data symbol of interpolation channel estimating of time-domain direction under the high-speed mobile environment descends.

Summary of the invention

The objective of the invention is in order to solve the low problem of existing channel method of estimation estimated accuracy under the high-speed mobile environment, proposed the channel estimation methods under a kind of high-speed mobile environment with high estimated accuracy.

To achieve these goals, concrete scheme of the present invention is: the channel estimation methods under a kind of high-speed mobile environment comprises the steps:

Step 1, the mobile radio system transmitting terminal sends the frame signal of starlike pilot frequency design or block pilot frequency design;

Step 2, the mobile radio system receiving terminal receives and extracts in the frame signal data of pilot sub-carrier position in the frequency pilot sign after the frame signal and carry out channel estimating based on basic extended model, obtains treating the column vector that the channel estimation value at pilot frequency symbol position place of the channel estimation value correspondence at data estimator character position place is formed;

Step 3 calculates the pilot frequency symbol position place of the channel estimation value correspondence for the treatment of data estimator character position place based on the corresponding optimal time of the channel estimation methods of basic extended model territory interpolation coefficient;

Step 4, the optimal time territory interpolation coefficient that the column vector that step 2 is obtained and step 3 obtain multiplies each other and obtains treating the channel estimation value at data estimator character position place.

Here, the described following formula of channel estimating utilization based on basic extended model of step 2 obtains the channel estimation value that time-domain d place treats k data sub-carrier positions of data estimator symbol place

The channel estimation value at k sub-carrier positions place of M frequency pilot sign, time corresponding territory

${\hat{H}}_{p_i}\left(k\right)=\frac{1}{N}\underset{l=0}{\overset{L-1}{\mathrm{\&Sigma;}}}\underset{n=0}{\overset{N-1}{\mathrm{\&Sigma;}}}\underset{q=0}{\overset{Q}{\mathrm{\&Sigma;}}}{\widehat{\mathrm{\&eta;}}}_{q,l}\left(p_i\right){\mathrm{<figure-callout\; id="2"\; label="e\; j"\; filenames="HDA0000055380330000021.png,HDA0000055380330000041.png"\; state="\{\{state\}\}">e</figure-callout>}}^{\frac{j}{}}{e}^{\frac{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HDA0000055380330000021.png,HDA0000055380330000041.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;kl}}{N}},$ k＝N _u，s，N _u，s+1，...，N _u，e，p _i，i＝1，2...，M，

Wherein, Expression time-domain d treats at the place channel estimation value at k data sub-carrier positions of data estimator symbol place

Time corresponding territory position p _iThe channel estimation value at k sub-carrier positions place of frequency pilot sign, place, η _{Q, l}(p _i) expression time-domain position p _iLocate frequency pilot sign corresponding to q the basic extended model coefficient in wireless channel l bar footpath,

Utilize time-domain position p _iThe data estimation of pilot sub-carrier position obtains in place's frequency pilot sign,

The estimated value of expression " * ", L represents the normalization multidiameter delay number of wireless channel, and N represents all subcarrier numbers, and Q represents the number of employed basic extended model coefficient, Q=2r, r=1,2 ..., G represents the over-sampling coefficient that basic extended model adopts, G 〉=1 and be real number, N _{U, s}Represent to distribute in a frequency pilot sign or the data symbol user's subcarrier original position, N _{U, e}Represent to distribute in a frequency pilot sign or the data symbol user's subcarrier end position, (N _{U, e}-N _{U, s}+ 1)≤and N, M represents to treat the channel estimation value number at the pilot frequency symbol position place, channel estimation value time corresponding territory at data estimator character position place, π represents circumference ratio,

" ∑ " expression summation operation.And then obtain the channel estimation value that time-domain d place treats k data sub-carrier positions of data estimator symbol place

The channel estimation value at k sub-carrier positions place of M frequency pilot sign, time corresponding territory

The column vector of forming

K=N _{U, s}, N _{U, s}+ 1 ..., N _{U, e}, " [] ^T" the transposition computing of expression " [] ".

Step 3 is described treats that the pilot frequency symbol position place of channel estimation value correspondence at data estimator character position place is based on the corresponding optimal time of the channel estimation methods of basic extended model territory interpolation coefficient

Calculate according to following formula:

${\hat{C}}_{d,\mathrm{optimal}}=\left[\begin{array}{cccc}{J}_0\left(2\mathrm{\&pi;}(d-p_1)f_{D}T\right)& J_0\left(2\mathrm{\&pi;}(d-p_2)f_{D}T\right)& ...& J_0\left(2\mathrm{\&pi;}(d-p_M)f_{D}T\right)\end{array}\right]$

$\&times;{\left[\begin{array}{cccc}1+\frac{(N_{u,e}-N_{u,s}+1)}{\mathrm{<figure-callout\; id="1"\; label="N"\; filenames="HDA0000055380330000011.png,HDA0000055380330000012.png"\; state="\{\{state\}\}">N</figure-callout>}10^{\frac{\mathrm{SNR}}{10}}}& J_0\left(2\mathrm{\&pi;}(p_1-p_2)f_{D}T\right)& ...& J_0\left(2\mathrm{\&pi;}(p_1-p_M)f_{D}T\right)\\ J_0\left(2\mathrm{\&pi;}(p_2-p_1)f_{D}T\right)& 1+\frac{(N_{u,e}-N_{u,s}+1)}{{\mathrm{<figure-callout\; id="10"\; label="N"\; filenames="HDA0000055380330000041.png,HDA0000055380330000042.png"\; state="\{\{state\}\}">N</figure-callout>}10}^{\frac{\mathrm{<figure-callout\; id="10"\; label="SNR"\; filenames="HDA0000055380330000041.png,HDA0000055380330000042.png"\; state="\{\{state\}\}">SNR</figure-callout>}}{10}}}& ...& J_0\left(2\mathrm{\&pi;}(p_2-p_M)f_{D}T\right)\\ ...& ...& ...& ...\\ J_0\left(2\mathrm{\&pi;}(p_M-p_1)f_{D}T\right)& J_0\left(2\mathrm{\&pi;}(p_M-p_2)f_{D}T\right)& ...& 1+\frac{(N_{u,e}-N_{u,s}+1)}{{\mathrm{<figure-callout\; id="10"\; label="N"\; filenames="HDA0000055380330000041.png,HDA0000055380330000042.png"\; state="\{\{state\}\}">N</figure-callout>}10}^{\frac{\mathrm{SNR}}{10}}}\end{array}\right]}^{-1},$

For the pilot frequency symbol position place that minimizes the channel estimation value correspondence for the treatment of data estimator character position place that the present invention provides under equal square evaluated error meanings based on the corresponding optimal time of the channel estimation methods of basic extended model territory interpolation coefficient, wherein, J ₀(*) expression the 0th rank Bessel function, f _DT is the normalization Doppler frequency of channel, and π represents circumference ratio, and SNR represents the power ratio of signal and noise in the channel, and d represents to treat that the data estimator symbol is at the position of time-domain, p _i, i=1,2..., M are illustrated in the channel estimation value at M pilot frequency symbol position place of the channel estimation value correspondence for the treatment of the data estimator symbol at d place, time-domain position in the position of time-domain, the multiplying of " * " representing matrix, the computing of "+" expression scalar addition, " [] ^-1" the representing matrix inversion operation.

Here the pilot sub-carrier in the frame signal uniformly-spaced evenly distributes in frequency pilot sign in the step 1, the insertion period T of pilot sub-carrier in frequency pilot sign _fSatisfy

τ _LΔ f is the maximum normalization multidiameter delay of channel, the insertion interval T of frequency pilot sign in frame signal _tSatisfy

f _DT is the normalization Doppler frequency of channel,

Expression is to the following rounding operation of " * ".

Beneficial effect of the present invention: the channel estimation methods based on basic extended model can estimate the variation of wireless channel in a symbol period under the high-speed mobile environment accurately, utilization of the present invention estimates the channel estimation value at pilot frequency symbol position place under the high-speed mobile environment accurately based on the channel estimation methods of basic extended model, and has provided calculating pilot frequency symbol position place based on the corresponding optimal time of the channel estimation methods of basic extended model territory interpolation coefficient formula.Thereby the present invention utilizes pilot frequency symbol position place channel estimation value and combine according to the optimal time territory interpolation coefficient that calculates and can estimate the channel estimation value at data symbol positions place under the high-speed mobile environment accurately accurately.Compare existing channel estimation methods, the present invention can significantly improve the precision of channel estimation of mobile radio system under the high-speed mobile environment.The present invention is applicable to that the mobile radio system to using starlike pilot frequency design or block pilot frequency design carries out channel estimating under high-speed mobile environment.

Description of drawings

Fig. 1 is the frame signal schematic diagram of the starlike pilot frequency design of mobile radio system.

Fig. 2 is the frame signal schematic diagram of the block pilot frequency design of mobile radio system.

Fig. 3 is the realization flow figure of the channel estimation methods under the high-speed mobile environment of the embodiment of the invention.

Fig. 4 is the mobile radio system frame signal structural representation of the embodiment of the invention.

Fig. 5 is the mobile radio system transmitting terminal of the embodiment of the invention and the information processing schematic diagram of receiving terminal.

When Fig. 6 was 16QAM and 64QAM for modulation system in the embodiment of the invention, translational speed was existing method 120 kilometers/hour under and the Block Error Rate performance simulation comparison schematic diagram of institute of the present invention extracting method.

When Fig. 7 was 16QAM and 64QAM for modulation system in the embodiment of the invention, translational speed was existing method 350 kilometers/hour under and the Block Error Rate performance simulation comparison schematic diagram of institute of the present invention extracting method.

Embodiment

Below in conjunction with accompanying drawing and specific embodiment method of the present invention is further elaborated.

In the present embodiment, provide channel estimation methods under a kind of high-speed mobile environment.Here the mobile radio system under the high-speed mobile speed environment is in the macrocellular environment, and the propagation medium in the radio signal propagation channel is isotropic to the scattering of wireless signal.

Here with following mobile radio system Long Term Evolution (LTE, Long Term Evolution) up-link is as the mobile radio system in the embodiment of the invention, the concrete parameter of LTE up-link is as shown in table 1 among the embodiment, wherein QAM (Quadrature Amplitude Modulation) expression quadrature amplitude modulation.

Table 1

All subcarrier number N	2048
		Distribute to user's subcarrier number	600
Modulation system	16QAM，64QAM
		Translational speed	120 kilometers/hour, 350 kilometers/hour

Below in conjunction with Fig. 3, Fig. 4 and Fig. 5 describe the processing procedure that realizes the channel estimation methods under the high-speed mobile environment in the present embodiment in detail.

Fig. 3 is the realization flow figure of the channel estimation methods under the high-speed mobile environment of the embodiment of the invention, specifically is unfolded as follows:

Step 1, the mobile radio system transmitting terminal sends the frame signal of starlike pilot frequency design or block pilot frequency design;

Step 2, the mobile radio system receiving terminal receives and extracts in the frame signal data of pilot sub-carrier position in the frequency pilot sign after the frame signal and carry out channel estimating based on basic extended model, obtains treating the column vector that the channel estimation value at pilot frequency symbol position place of the channel estimation value correspondence at data estimator character position place is formed;

Step 3 calculates the pilot frequency symbol position place of the channel estimation value correspondence for the treatment of data estimator character position place based on the corresponding optimal time of the channel estimation methods of basic extended model territory interpolation coefficient;

Step 4, the optimal time territory interpolation coefficient that obtains in the column vector that obtains in the above-mentioned steps 2 and the step 3 multiplied each other obtains treating the channel estimation value at data estimator character position place.

Fig. 4 is the mobile radio system frame signal structural representation of the embodiment of the invention.Frame signal is made up of 14 symbols on the time-domain in the LTE up-link, and these 14 symbols comprise the Sounding symbol of data symbol, frequency pilot sign, current frame signal.When the mobile radio system receiving terminal of present embodiment is implemented the present invention, also to use the Sounding symbol of previous frame signal, shown in the symbol that 0 place, time-domain position of Fig. 4 is represented.Because enforcement of the present invention may relate to the frequency pilot sign of a plurality of time-domains, so embodiments of the invention had both been considered frequency pilot sign in the LTE up-link, again with third generation affiliate (3GPP, 3rd Generation Partnership Project) the auxiliary time-domain interpolation channel estimating of carrying out of Sounding symbol in Gui Ding the LTE up-link, 3GPP regulation Sounding symbol be the base station in order to assess the symbol of channel quality, the Sounding symbol can be used as the extra pilots symbol as known symbol.So, when the mobile radio system receiving terminal of embodiment was implemented the present invention, the Sounding symbol of frame signal as shown in Figure 4 and previous frame signal comprised 4 frequency pilot signs altogether.Not only comprised starlike pilot frequency design but also comprised block pilot frequency design in the mobile radio system frame signal of the embodiment of the invention as can be seen, very representative.

Fig. 5 is the mobile radio system transmitting terminal of the embodiment of the invention and the information processing schematic diagram of receiving terminal.Marked out the position of the channel estimation methods treatment step under the high-speed mobile environment of the embodiment of the invention among the figure.CRC represents cyclic redundancy effect sign indicating number among the figure, and IDFT represents the discrete fourier inverse transformation, and CP represents Cyclic Prefix, and DFT represents discrete Fourier transform.

The concrete treatment step of present embodiment is as follows:

Step 1, LTE up-link transmitting terminal sends frame signal as shown in Figure 4.

Step 2, LTE up-link receiving terminal receives and extracts in the frame signal data of pilot sub-carrier position in the frequency pilot sign after the frame signal and carry out channel estimating based on basic extended model, obtains the channel estimation value that time-domain d place treats k data sub-carrier positions of data estimator symbol place

D=1-3,5-10,12-13, k=13,14 ..., the column vector that the channel estimation value at the pilot frequency symbol position place of 612 correspondences is formed: in the present embodiment, for

D=1-3,5-7, k=13,14 ..., the column vector that the channel estimation value at the pilot frequency symbol position place of 612 correspondences is formed is chosen as

K=13,14 ..., 612; For

D=8-10,12-13, k=13,14 ..., the column vector that the channel estimation value at the pilot frequency symbol position place of 612 correspondences is formed is chosen as

K=13,14 ..., 612.Especially, the number Q=2 of employed basic extended model coefficient, the over-sampling coefficient G that basic extended model adopts selects suitable value according to different translational speeds.

Step 3, computing time, d place in territory treated the channel estimation value at k data sub-carrier positions of data estimator symbol place D=1-3,5-10,12-13, k=13,14 ..., the pilot frequency symbol position place of 612 correspondences is based on the corresponding optimal time of the channel estimation methods of basic extended model territory interpolation coefficient

According to step 2 as can be seen: in the embodiment of the invention, for

D=1-3,5-7, k=13,14 ..., the channel estimation value number M=3 at pilot frequency symbol position place, 612 time corresponding territory, the channel estimation value at corresponding pilot frequency symbol position place is at the position of time-domain p ₁=0, p ₂=4, p ₃=11; For

D=8-10,12-13, k=13,14 ..., the channel estimation value number M=3 at pilot frequency symbol position place, 612 time corresponding territory, the channel estimation value at corresponding pilot frequency symbol position place is at the position of time-domain p ₁=4, p ₂=11, p ₃=14.The above-mentioned parameter substitution is treated the pilot frequency symbol position place of channel estimation value correspondence at data estimator character position place is based on the corresponding optimal time of the channel estimation methods of basic extended model territory interpolation coefficient:

${\hat{C}}_{d,\mathrm{optimal}}=\left[\begin{array}{cccc}{J}_0\left(2\mathrm{\&pi;}(d-p_1)f_{D}T\right)& J_0\left(2\mathrm{\&pi;}(d-p_2)f_{D}T\right)& ...& J_0\left(2\mathrm{\&pi;}(d-p_M)f_{D}T\right)\end{array}\right]$

$\&times;{\left[\begin{array}{cccc}1+\frac{(N_{u,e}-N_{u,s}+1)}{\mathrm{<figure-callout\; id="1"\; label="N"\; filenames="HDA0000055380330000011.png,HDA0000055380330000012.png"\; state="\{\{state\}\}">N</figure-callout>}10^{\frac{\mathrm{SNR}}{10}}}& J_0\left(2\mathrm{\&pi;}(p_1-p_2)f_{D}T\right)& ...& J_0\left(2\mathrm{\&pi;}(p_1-p_M)f_{D}T\right)\\ J_0\left(2\mathrm{\&pi;}(p_2-p_1)f_{D}T\right)& 1+\frac{(N_{u,e}-N_{u,s}+1)}{{\mathrm{<figure-callout\; id="10"\; label="N"\; filenames="HDA0000055380330000041.png,HDA0000055380330000042.png"\; state="\{\{state\}\}">N</figure-callout>}10}^{\frac{\mathrm{<figure-callout\; id="10"\; label="SNR"\; filenames="HDA0000055380330000041.png,HDA0000055380330000042.png"\; state="\{\{state\}\}">SNR</figure-callout>}}{10}}}& ...& J_0\left(2\mathrm{\&pi;}(p_2-p_M)f_{D}T\right)\\ ...& ...& ...& ...\\ J_0\left(2\mathrm{\&pi;}(p_M-p_1)f_{D}T\right)& J_0\left(2\mathrm{\&pi;}(p_M-p_2)f_{D}T\right)& ...& 1+\frac{(N_{u,e}-N_{u,s}+1)}{{\mathrm{<figure-callout\; id="10"\; label="N"\; filenames="HDA0000055380330000041.png,HDA0000055380330000042.png"\; state="\{\{state\}\}">N</figure-callout>}10}^{\frac{\mathrm{SNR}}{10}}}\end{array}\right]}^{-1}$

The normalization Doppler frequency f of channel wherein _DThe transmission carrier frequency that T can adopt according to mobile radio system, transmission bandwidth and translational speed calculate.The optimal time territory interpolation coefficient that calculates according to above formula is:

${\hat{C}}_{d,\mathrm{optimal}}=\left[\begin{array}{ccc}{\hat{w}}_{d,1}& {\hat{w}}_{d,2}& {\hat{w}}_{d,3}\end{array}\right]$ d＝1-3，5-10，12-13。

Step 4, the column vector that the channel estimation value at k the sub-carrier positions place of time-domain M frequency pilot sign that obtain in the above-mentioned steps 2 is formed

K=13,14 ..., 612 with step 3 in the pilot frequency symbol position place that obtains based on the corresponding optimal time of the channel estimation methods of basic extended model territory interpolation coefficient

D=1-3,5-10,12-13 multiply each other and obtain time-domain d place and treat k data sub-carrier positions of data estimator symbol place channel estimation value

D=1-3,5-10,12-13, k=13,14 ..., 612:

${\hat{H}}_d\left(k\right)={\hat{w}}_{d,1}{\hat{H}}_0\left(k\right)+{\hat{w}}_{d,2}{\hat{H}}_4\left(k\right)+{\hat{w}}_{d,3}{\hat{H}}_{11}\left(k\right),$ d＝1-3，5-7，k＝13，14，...，612

${\hat{H}}_d\left(k\right)={\hat{w}}_{d,1}{\hat{H}}_4\left(k\right)+{\hat{w}}_{d,2}{\hat{H}}_{11}\left(k\right)+{\hat{w}}_{d,3}{\hat{H}}_{14}\left(k\right),$ d＝8-10，12-13，k＝13，14，...，612

Abscissa is represented the power ratio (SNR of signal and noise in the channel among Fig. 6, Fig. 7, Signal to Noise Ratio), ordinate is represented Block Error Rate (BLER, Block Error Rate), be respectively when modulation system is 16QAM and 64QAM in the embodiment of the invention, translational speed is under 120 kilometers/hour, under 350 kilometers/hour, according to the system Block Error Rate performance simulation result of parameter in the table 1 under Extended Vehicular A (EVA) channel of LTE regulation.Emulation comparison schematic diagram by Fig. 6 can find that 120 kilometers/hour of translational speeds, under modulation system 16QAM and the 64QAM, institute of the present invention extracting method has the performance boost of about 1dB with respect to existing LS method.Emulation comparison schematic diagram by Fig. 7 can find that 350 kilometers/hour of translational speeds, under the modulation system 16QAM, method of the present invention has the performance boost of about 2.5dB with respect to existing LS method; 350 kilometers/hour of translational speeds, under the modulation system 64QAM, institute of the present invention extracting method has the performance boost of about 3.5dB with respect to existing LS method.Therefore, the emulation comparison schematic diagram of complex chart 6 and Fig. 7 can be found, under high-speed mobile environment, method of the present invention has tangible performance boost with respect to existing method, has namely significantly improved the precision of channel estimation of mobile radio system under the high-speed mobile environment.

Those of ordinary skill in the art will appreciate that embodiment described here is in order to help reader understanding's principle of the present invention, should to be understood that the protection range of inventing is not limited to such special statement and embodiment.Everyly make various possible being equal to according to foregoing description and replace or change, all be considered to belong to the protection range of claim of the present invention.

Claims (3)

1. the channel estimation methods under the high-speed mobile environment is characterized in that, comprises the steps:

Step 1, the mobile radio system transmitting terminal sends the frame signal of starlike pilot frequency design or block pilot frequency design;

Step 2, the mobile radio system receiving terminal receives and extracts in the frame signal data of pilot sub-carrier position in the frequency pilot sign after the frame signal and carry out channel estimating based on basic extended model, obtains treating the column vector that the channel estimation value at pilot frequency symbol position place of the channel estimation value correspondence at data estimator character position place is formed;

Step 3 calculates the pilot frequency symbol position place of the channel estimation value correspondence for the treatment of data estimator character position place based on the corresponding optimal time of the channel estimation methods of basic extended model territory interpolation coefficient;

Step 4, the optimal time territory interpolation coefficient that the column vector that step 2 is obtained and step 3 obtain multiplies each other and obtains treating the channel estimation value at data estimator character position place;

The following formula of channel estimating utilization based on basic extended model described in the step 2 obtains the channel estimation value that time-domain d place treats k data sub-carrier positions of data estimator symbol place

The channel estimation value at k sub-carrier positions place of M frequency pilot sign, time corresponding territory

k＝N _u,s,N _u,s+1,...,N _u,e，p _i,i＝1,2...,M，

Wherein,

Expression time-domain d treats at the place channel estimation value at k data sub-carrier positions of data estimator symbol place

Time corresponding territory position p _iThe channel estimation value at k sub-carrier positions place of frequency pilot sign, place, η _{Q, l}(p _i) expression time-domain position p _iLocate frequency pilot sign corresponding to q the basic extended model coefficient in wireless channel l bar footpath, Utilize time-domain position p _iThe data estimation of pilot sub-carrier position obtains in place's frequency pilot sign,

The estimated value of expression " * ", L represents the normalization multidiameter delay number of wireless channel, and N represents all subcarrier numbers, and Q represents the number of employed basic extended model coefficient, Q=2r, r=1,2 ..., G represents the over-sampling coefficient that basic extended model adopts, G 〉=1 and be real number, N _{U, s}Represent to distribute in a frequency pilot sign or the data symbol user's subcarrier original position, N _{U, e}Represent to distribute in a frequency pilot sign or the data symbol user's subcarrier end position, (N _{U, e}-N _{U, s}+ 1)≤and N, M represents to treat the channel estimation value number at the pilot frequency symbol position place, channel estimation value time corresponding territory at data estimator character position place, π represents circumference ratio, " Σ " represents summation operation, and then obtains the channel estimation value that time-domain d place treats k data sub-carrier positions of data estimator symbol place

The channel estimation value at k sub-carrier positions place of M frequency pilot sign, time corresponding territory

The column vector of forming

K=N _{U, s}, N _{U, s}+ 1 ..., N _{U, e}, " [] ^T" the transposition computing of expression " [] ".

2. the channel estimation methods under the high-speed mobile environment according to claim 1, it is characterized in that the pilot frequency symbol position place of the channel estimation value correspondence for the treatment of data estimator character position place described in the step 3 is based on the corresponding optimal time of the channel estimation methods of basic extended model territory interpolation coefficient Calculate according to following formula:

For the pilot frequency symbol position place that minimizes the channel estimation value correspondence for the treatment of data estimator character position place under equal square evaluated error meanings based on the corresponding optimal time of the channel estimation methods of basic extended model territory interpolation coefficient, wherein, J ₀(*) expression the 0th rank Bessel function, f _DT is the normalization Doppler frequency of channel, and π represents circumference ratio, and SNR represents the power ratio of signal and noise in the channel, and d represents to treat that the data estimator symbol is at the position of time-domain, p _i, i=1,2..., M are illustrated in the channel estimation value at M pilot frequency symbol position place of the channel estimation value correspondence for the treatment of the data estimator symbol at d place, time-domain position in the position of time-domain, the multiplying of " * " representing matrix, the computing of "+" expression scalar addition, " [] ^-1" the representing matrix inversion operation.

3. the channel estimation methods under the high-speed mobile environment according to claim 1 and 2 is characterized in that, the pilot sub-carrier in the frame signal described in the step 1 uniformly-spaced evenly distributes in frequency pilot sign, the insertion period T of pilot sub-carrier in frequency pilot sign _fSatisfy

τ _LΔ f is the maximum normalization multidiameter delay of channel, the insertion interval T of frequency pilot sign in frame signal _tSatisfy

f _DT is the normalization Doppler frequency of channel,

Expression is to the following rounding operation of " * ".

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