CN102185803A - 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

A Channel Estimation Method in High-speed Mobile Environment

technical field

The invention relates to the field of wireless mobile communication, in particular to a channel estimation method therein.

Background technique

With the vigorous construction of high-speed railways around the world, the normal communication of wireless mobile communication technology in a high-speed mobile environment (120 km/h, 350 km/h or higher) is an urgent problem to be solved, and it is suitable for this high-speed mobile environment. The high-precision channel estimation method is a difficult problem to be solved urgently. In order to improve the transmission rate and spectrum utilization rate of the wireless mobile communication system, users will be allocated a certain number of subcarriers among all the subcarriers in the frame signal of the wireless mobile communication system for communication. At present, the research on channel estimation methods under different mobile speed environments mainly focuses on the channel estimation method based on pilot subcarriers. This method first uses the pilot subcarriers allocated to users in pilot symbols to obtain the pilot subcarriers allocated to users in pilot symbols. The channel estimates at the frequency subcarrier positions are then interpolated in the frequency domain and time domain respectively to obtain channel estimates at all subcarrier positions allocated to users in the pilot symbols and data symbols.

k＝N_u，s，N_u，s+1，...，N_u，e对应的M个导频符号位置处的信道估计值在时间域的位置为p_i，i＝1，2...，M，令这M个导频符号第k个子载波位置处的信道估计值组成的列向量为

k＝N_u，s，N_u，s+1，...，N_u，e，其中N_u，s表示一个导频符号或一个数据符号中分配给用户的子载波起始位置，N_u，e表示一个导频符号或一个数据符号中分配给用户的子载波结束位置，表示“*”的估计值，“[]^T”表示“[]”的转置运算。则时间域d处待估计数据符号第k个数据子载波位置处信道估计值

k＝N_u，s，N_u，s+1，...，N_u，e可由

内插得出，令该时间域内插系数为为一大小为1×M的行向量，则时间域d处待估计数据符号第k个数据子载波位置处信道估计值

k＝N_u，s，N_u，s+1，...，N_u，e。Typical frame signals of wireless mobile communication systems are shown in Figures 1 and 2. Figure 1 is called the frame signal of the star pilot pattern, and Figure 2 is called the frame signal of the block pilot pattern. In Figure 1 and Figure 2, a column Represents a symbol, such as an Orthogonal Frequency Division Multiplexing (OFDM, Orthogonal Frequency Division Multiplexing) symbol, a symbol is composed of several subcarriers, the small black square represents the pilot subcarrier, and the small white square represents the data subcarrier, as shown in Figure 1 and In Fig. 2, symbols containing pilot subcarriers are called pilot symbols, and symbols in which all subcarriers are data subcarriers are called data symbols. The estimated value of the channel at the position of the kth data subcarrier of the data symbol to be estimated at the time domain d

k=N _{u, s} , Nu _{, s} + 1,..., Nu _{, e} corresponding to the channel estimation values at the M pilot symbol positions in the time domain are p _i , i=1, 2. .., M, let the column vector composed of the channel estimation value at the kth subcarrier position of these M pilot symbols be

k=N _{u, s} , Nu _{, s} +1,..., Nu _{, e} , where Nu _{, s} represents the starting position of the subcarrier allocated to the user in a pilot symbol or a data symbol, _{and Nu , e} represents the end position of the subcarrier allocated to the user in a pilot symbol or a data symbol, Indicates the estimated value of "*", and "[] ^T "indicates the transpose operation of "[]". Then the estimated value of the channel at the position of the kth data subcarrier of the data symbol to be estimated in the time domain d is

k=N _{u, s} , Nu _{, s} +1,..., _{Nu, e} can be determined by

Interpolated, let the time domain interpolation coefficient be is a row vector with a size of 1×M, then the channel estimation value at the position of the kth data subcarrier of the data symbol to be estimated in the time domain d

k=N _u,s , N _u,s +1, . . . , N _u,e .

The existing channel estimation method under the high-speed mobile environment mainly uses the method based on least squares (LS, least squares) to estimate the channel estimation value at the pilot subcarrier position allocated to the user in the pilot symbol (or the channel estimation value Values for further various transformation domain filtering processing), and then perform interpolation channel estimation in the frequency domain direction to obtain channel estimation values at all subcarrier positions allocated to users in the pilot symbols, and finally perform interpolation in the time domain direction Channel estimation, thereby estimating channel estimation values at all subcarrier positions allocated to the user in the data symbol. The disadvantages of this method are: (1) This method assumes that the wireless channel is static within a symbol period, but in a high-speed mobile environment, the wireless channel changes rapidly, and the wireless channel is static within a symbol period. is no longer true, resulting in a decrease in the channel estimation accuracy of the LS-based method at the pilot subcarrier position allocated to the user in the pilot symbol; (2) due to the LS-based method in the pilot symbol allocated to the user The channel estimation accuracy at the subcarrier position decreases, which leads to the decrease of the channel estimation accuracy at the subcarrier position of the data allocated to the user in the pilot symbols obtained by interpolating the channel estimation in the frequency domain direction, which in turn leads to the decrease of the channel estimation accuracy at the subcarrier position of the pilot symbol in the high-speed mobile environment. The channel estimation accuracy at all subcarrier positions allocated to the user in the symbol decreases; (3) due to the decrease in the channel estimation accuracy at all subcarrier positions allocated to the user in the pilot symbol, it finally leads to the time domain direction in the high-speed mobile environment. The accuracy of channel estimation at all subcarrier positions allocated to users in the data symbols obtained by interpolating channel estimation decreases.

Contents of the invention

The object of the present invention is to solve the problem of low estimation accuracy of the existing channel estimation method in the high-speed mobile environment, and propose a channel estimation method in the high-speed mobile environment with high estimation accuracy.

In order to achieve the above object, a specific solution of the present invention is: a channel estimation method under a high-speed mobile environment, comprising the steps of:

Step 1, the transmitting end of the wireless mobile communication system sends a frame signal of a star pilot pattern or a block pilot pattern;

Step 2: After receiving the frame signal, the receiving end of the wireless mobile communication system extracts the data at the pilot subcarrier position in the pilot symbol in the frame signal to perform channel estimation based on the base extension model, and obtains the channel estimation value at the position of the data symbol to be estimated A column vector composed of channel estimation values at corresponding pilot symbol positions;

Step 3, calculating the optimal time-domain interpolation coefficient corresponding to the channel estimation method based on the base extension model at the pilot symbol position corresponding to the channel estimation value at the position of the data symbol to be estimated;

Step 4: Multiply the column vector obtained in step 2 with the optimal time-domain interpolation coefficient obtained in step 3 to obtain an estimated channel value at the position of the data symbol to be estimated.

Here, the channel estimation based on the base extension model described in step 2 uses the following formula to obtain the channel estimation value at the position of the kth data subcarrier of the data symbol to be estimated in the time domain d The channel estimation value at the kth subcarrier position of the corresponding M pilot symbols in the time domain

${\hat{h}}_{p_i}\left(k\right)=\frac{1}{N}\underset{l=0}{\overset{L-1}{\mathrm{\&Sigma;}}}\underset{\mathrm{no}=0}{\overset{N-1}{\mathrm{\&Sigma;}}}\underset{q=0}{\overset{Q}{\mathrm{\&Sigma;}}}{\widehat{\mathrm{\&eta;}}}_{q,l}\left(p_i\right){\mathrm{<figure-callout\; id="2"\; label="e\; j"\; filenames="HDA0000055380330000021.png,HDA0000055380330000031.png"\; state="\{\{state\}\}">e</figure-callout>}}^{\frac{j}{}}{e}^{\frac{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HDA0000055380330000021.png,HDA0000055380330000031.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;kl}}{N}},$ k=N _u,s , Nu _,s +1,...,N _u,e ,p _i , i=1,2...,M,

表示时间域d处待估计数据符号第k个数据子载波位置处的信道估计值对应的时间域位置p_i处导频符号第k个子载波位置处的信道估计值，η_q，l(p_i)表示时间域位置p_i处导频符号对应于无线信道第l条径的第q个基扩展模型系数，利用时间域位置p_i处导频符号中导频子载波位置处的数据估计获得，

表示“*”的估计值，L表示无线信道的归一化多径时延数，N表示所有的子载波个数，Q表示所使用的基扩展模型系数的个数，Q＝2r，r＝1，2，...，G表示基扩展模型所采用的过采样系数，G≥1且为实数，N_u，s表示一个导频符号或一个数据符号中分配给用户的子载波起始位置，N_u，e表示一个导频符号或一个数据符号中分配给用户的子载波结束位置，(N_u，e-N_u，s+1)≤N，M表示待估计数据符号位置处的信道估计值对应的时间域导频符号位置处的信道估计值个数，π表示圆周率，“∑”表示求和运算。进而得到时间域d处待估计数据符号第k个数据子载波位置处的信道估计值

对应的时间域M个导频符号第k个子载波位置处的信道估计值

组成的列向量k＝N_u，s，N_u，s+1，...，N_u，e，“[]^T”表示“[]”的转置运算。in,

Indicates the channel estimate at the position of the kth data subcarrier of the data symbol to be estimated in the time domain d Corresponding to the channel estimation value at the kth subcarrier position of the pilot symbol at the position p _i in the time domain, η _{q, l} (p _i ) indicates that the pilot symbol at the position p _i in the time domain corresponds to the first path of the lth path of the wireless channel q base extension model coefficients, Obtained using the data estimation at the pilot subcarrier position in the pilot symbol at position p _i in the time domain,

Represents the estimated value of "*", L represents the normalized multipath time delay number of the wireless channel, N represents the number of all subcarriers, Q represents the number of coefficients of the basic extension model used, Q=2r, r= 1, 2, ..., G represents the oversampling coefficient adopted by the base extension model, G≥1 and is a real number, _{Nu, s} represents the starting position of the subcarrier allocated to the user in a pilot symbol or a data symbol , Nu _{, e} represent the end position of the subcarrier allocated to the user in a pilot symbol or a data symbol, (N _{u, e} -N _{u, s} +1) ≤ N, M represents the channel at the position of the data symbol to be estimated The number of channel estimation values at the position of the time-domain pilot symbol corresponding to the estimated value, π represents the circumference ratio, "∑" indicates a sum operation. Then, the channel estimation value at the position of the kth data subcarrier of the data symbol to be estimated in the time domain d is obtained

The channel estimation value at the kth subcarrier position of the corresponding M pilot symbols in the time domain

A column vector consisting of k ⁼ N _{u, s} , Nu _{, s} +1, .

按照以下公式计算出：The optimal time-domain interpolation coefficient corresponding to the channel estimation method based on the base extension model at the pilot symbol position corresponding to the channel estimation value at the position of the data symbol to be estimated in step 3

Calculated according to the following formula:

${\stackrel{<span\; class="notranslate">\; ^</span>}{\mathrm{<span\; class="notranslate">\; C</span>}}}_{\mathrm{<span\; class="notranslate">\; d</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; optimal</span>}}<span\; class="notranslate">\; =</span>\left[\begin{array}{cccc}{\mathrm{<span\; class="notranslate">\; J</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&pi;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; d</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}}\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; )</span>& {\mathrm{<span\; class="notranslate">\; J</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&pi;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; d</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}}\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; )</span>& <span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span>& {\mathrm{<span\; class="notranslate">\; J</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&pi;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; d</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}}\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; )</span>\end{array}\right]$

$<span\; class="notranslate">\; \&times;</span>{\left[\begin{array}{cccc}\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\frac{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; u</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; e</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; u</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="N"\; filenames="HDA0000055380330000011.png,HDA0000055380330000012.png"\; state="\{\{state\}\}">N</figure-callout></span>}\mathrm{<span\; class="notranslate">\; 1</span>}{\mathrm{<span\; class="notranslate">\; 0</span>}}^{\frac{\mathrm{<span\; class="notranslate">\; SNR</span>}}{\mathrm{<span\; class="notranslate">\; 10</span>}}}}& {\mathrm{<span\; class="notranslate">\; J</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&pi;</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}}\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; )</span>& <span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span>& {\mathrm{<span\; class="notranslate">\; J</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&pi;</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}}\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; )</span>\\ {\mathrm{<span\; class="notranslate">\; J</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&pi;</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}}\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; )</span>& \mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\frac{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; u</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; e</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; u</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>}{{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="10"\; label="N"\; filenames="HDA0000055380330000031.png,HDA0000055380330000041.png"\; state="\{\{state\}\}">N</figure-callout></span>}\mathrm{<span\; class="notranslate">\; 10</span>}}^{\frac{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="10"\; label="SNR"\; filenames="HDA0000055380330000031.png,HDA0000055380330000041.png"\; state="\{\{state\}\}">SNR</figure-callout></span>}}{\mathrm{<span\; class="notranslate">\; 10</span>}}}}& <span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span>& {\mathrm{<span\; class="notranslate">\; J</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&pi;</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}}\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; )</span>\\ <span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span>& <span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span>& <span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span>& <span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span>\\ {\mathrm{<span\; class="notranslate">\; J</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&pi;</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}}\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; )</span>& {\mathrm{<span\; class="notranslate">\; J</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&pi;</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}}\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; )</span>& <span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span>& \mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\frac{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; u</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; e</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; u</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>}{{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="10"\; label="N"\; filenames="HDA0000055380330000031.png,HDA0000055380330000041.png"\; state="\{\{state\}\}">N</figure-callout></span>}\mathrm{<span\; class="notranslate">\; 10</span>}}^{\frac{\mathrm{<span\; class="notranslate">\; SNR</span>}}{\mathrm{<span\; class="notranslate">\; 10</span>}}}}\end{array}\right]}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; ,</span>$

In order to minimize the mean square estimation error, the optimal time-domain interpolation coefficient corresponding to the channel estimation method based on the base extension model at the pilot symbol position corresponding to the channel estimation value at the position of the data symbol to be estimated given by the present invention, where , J ₀ (*) represents the 0th order Bessel function, f _D T is the normalized Doppler frequency of the channel, π represents the circular ratio, SNR represents the power ratio of signal to noise in the channel, and d represents the data symbol to be estimated Positions in the time domain, p _i , i=1, 2..., M represents the channel estimation values at the M pilot symbol positions corresponding to the channel estimation values of the data symbols to be estimated at position d in the time domain at time The position of the field, "×" indicates matrix multiplication operation, "+" indicates scalar addition operation, and "[] ^-1 "indicates matrix inversion operation.

f_DT为信道的归一化多普勒频率，

表示对“*”的下取整运算。Here in step 1, the pilot subcarriers in the frame signal are evenly distributed in the pilot symbols, and the insertion period T _f of the pilot subcarriers in the pilot symbols satisfies τ _L Δf is the maximum normalized multipath delay of the channel, and the insertion interval T _t of pilot symbols in the frame signal satisfies

f _D T is the normalized Doppler frequency of the channel,

Indicates the floor operation of "*".

Beneficial effects of the present invention: the channel estimation method based on the base spread model can accurately estimate the change of the wireless channel within one symbol period in a high-speed mobile environment, and the present invention can accurately estimate the high-speed mobile channel by using the channel estimation method based on the base spread model. The channel estimation value at the position of the pilot symbol in the environment, and the optimal time-domain interpolation coefficient formula corresponding to the channel estimation method based on the base spread model at the position of the pilot symbol is given. The present invention can accurately estimate the channel estimation value at the data symbol position under the high-speed mobile environment by combining the accurate channel estimation value at the pilot symbol position and the optimal time domain interpolation coefficient obtained according to calculation. Compared with the existing channel estimation method, the invention can significantly improve the channel estimation accuracy of the wireless mobile communication system under the high-speed mobile environment. The invention is suitable for channel estimation in a high-speed mobile environment of a wireless mobile communication system using a star pilot pattern or a block pilot pattern.

Description of drawings

FIG. 1 is a schematic diagram of a frame signal of a star pilot pattern in a wireless mobile communication system.

FIG. 2 is a schematic diagram of a frame signal of a block pilot pattern in a wireless mobile communication system.

Fig. 3 is a flow chart of implementing a channel estimation method in a high-speed mobile environment according to an embodiment of the present invention.

FIG. 4 is a schematic diagram of a frame signal structure of a wireless mobile communication system according to an embodiment of the present invention.

FIG. 5 is a schematic diagram of information processing at the sending end and the receiving end of the wireless mobile communication system according to an embodiment of the present invention.

Fig. 6 is a schematic diagram of the block error rate performance simulation comparison between the existing method and the method proposed in the present invention at a moving speed of 120 km/h when the modulation modes are 16QAM and 64QAM in the embodiment of the present invention.

FIG. 7 is a schematic diagram of the block error rate performance simulation comparison between the existing method and the method proposed in the present invention at a moving speed of 350 km/h when the modulation modes are 16QAM and 64QAM in the embodiment of the present invention.

Detailed ways

The method of the present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

In this embodiment, a channel estimation method in a high-speed mobile environment is provided. Here, the wireless mobile communication system under the high-speed mobile speed environment is in the macro-cellular environment, and the propagation medium in the wireless signal propagation channel is isotropic in scattering of the wireless signal.

Here, the uplink system of the future wireless mobile communication system Long Term Evolution (LTE, Long Term Evolution) is used as the wireless mobile communication system in the embodiment of the present invention, and the specific parameters of the LTE uplink system in the embodiment are as shown in Table 1, wherein QAM (Quadrature Amplitude Modulation) means quadrature amplitude modulation.

Table 1

The number of all subcarriers N 2048 The number of subcarriers allocated to users 600 Modulation 16QAM, 64QAM Moving speed 120 km/h, 350 km/h

The processing procedure for implementing the channel estimation method in the high-speed mobile environment in this embodiment will be described in detail below with reference to FIG. 3 , FIG. 4 and FIG. 5 .

Fig. 3 is the implementation flowchart of the channel estimation method under the high-speed mobile environment of the embodiment of the present invention, specifically expanded as follows:

Step 1, the transmitting end of the wireless mobile communication system sends a frame signal of a star pilot pattern or a block pilot pattern;

Step 2: After receiving the frame signal, the receiving end of the wireless mobile communication system extracts the data at the pilot subcarrier position in the pilot symbol in the frame signal to perform channel estimation based on the base extension model, and obtains the channel estimation value at the position of the data symbol to be estimated A column vector composed of channel estimation values at corresponding pilot symbol positions;

Step 3, calculating the optimal time-domain interpolation coefficient corresponding to the channel estimation method based on the base extension model at the pilot symbol position corresponding to the channel estimation value at the position of the data symbol to be estimated;

Step 4: Multiply the column vector obtained in the above step 2 by the optimal time-domain interpolation coefficient obtained in step 3 to obtain the estimated channel value at the symbol position of the data to be estimated.

FIG. 4 is a schematic diagram of a frame signal structure of a wireless mobile communication system according to an embodiment of the present invention. The frame signal in the LTE uplink system consists of 14 symbols in the time domain, and the 14 symbols include data symbols, pilot symbols, and Sounding symbols of the current frame signal. When the receiving end of the wireless mobile communication system of this embodiment implements the present invention, the Sounding symbol of the previous frame signal is also used, as shown by the symbol at position 0 in the time domain of FIG. 4 . Since the implementation of the present invention may involve pilot symbols in multiple time domains, the embodiments of the present invention have not only considered the pilot symbols in the LTE uplink system, but also stipulated in the 3rd Generation Partnership Project (3GPP, 3rd Generation Partnership Project) In the LTE uplink system, the Sounding symbol assists in time-domain interpolation channel estimation. 3GPP stipulates that the Sounding symbol is a symbol used by the base station to evaluate the channel quality. As a known symbol, the Sounding symbol can be used as an additional pilot symbol. Then, when the present invention is implemented at the receiving end of the wireless mobile communication system of the embodiment, the frame signal shown in FIG. 4 and the Sounding symbol of the previous frame signal contain 4 pilot symbols in total. It can be seen that the frame signal of the wireless mobile communication system according to the embodiment of the present invention includes both a star pilot pattern and a block pilot pattern, which is very typical.

FIG. 5 is a schematic diagram of information processing at the sending end and the receiving end of the wireless mobile communication system according to an embodiment of the present invention. In the figure, the positions of the processing steps of the channel estimation method in the high-speed mobile environment of the embodiment of the present invention are marked. In the figure, CRC means cyclic redundancy check code, IDFT means inverse discrete Fourier transform, CP means cyclic prefix, and DFT means discrete Fourier transform.

The specific processing steps of this embodiment are as follows:

In step 1, the transmitting end of the LTE uplink system transmits the frame signal as shown in FIG. 4 .

d＝1-3，5-10，12-13，k＝13，14，...，612对应的导频符号位置处的信道估计值组成的列向量：本实施例中，对于

d＝1-3，5-7，k＝13，14，...，612对应的导频符号位置处的信道估计值组成的列向量选择为

k＝13，14，...，612；对于

d＝8-10，12-13，k＝13，14，...，612对应的导频符号位置处的信道估计值组成的列向量选择为k＝13，14，...，612。特别的，所使用的基扩展模型系数的个数Q＝2，基扩展模型所采用的过采样系数G根据不同的移动速度选择合适的值。Step 2. After receiving the frame signal, the receiving end of the LTE uplink system extracts the data at the position of the pilot subcarrier in the pilot symbol in the frame signal to perform channel estimation based on the base extension model, and obtain the kth data symbol to be estimated at the time domain d Channel estimates at data subcarrier locations

d=1-3, 5-10, 12-13, k=13, 14, ..., 612 column vectors composed of channel estimation values corresponding to pilot symbol positions:

d=1-3, 5-7, k=13, 14, ..., the column vector composed of the channel estimation value at the pilot symbol position corresponding to 612 is selected as

k=13,14,...,612; for

d=8-10, 12-13, k=13, 14, ..., the column vector composed of the channel estimation value at the pilot symbol position corresponding to 612 is selected as k=13, 14, . . . , 612. In particular, the number of coefficients of the basic extended model used is Q=2, and the oversampling coefficient G adopted by the basic extended model is selected according to different moving speeds.

d＝1-3，5-10，12-13，k＝13，14，...，612对应的导频符号位置处基于基扩展模型的信道估计方法所对应的最优时间域内插系数

根据步骤2可以看出：本发明实施例中，对于

d＝1-3，5-7，k＝13，14，...，612对应的时间域导频符号位置处的信道估计值个数M＝3，对应的导频符号位置处的信道估计值在时间域的位置p₁＝0，p₂＝4，p₃＝11；对于

d＝8-10，12-13，k＝13，14，...，612对应的时间域导频符号位置处的信道估计值个数M＝3，对应的导频符号位置处的信道估计值在时间域的位置p₁＝4，p₂＝11，p₃＝14。将上述参数代入待估计数据符号位置处的信道估计值对应的导频符号位置处基于基扩展模型的信道估计方法所对应的最优时间域内插系数：Step 3, calculate the channel estimation value at the kth data subcarrier position of the data symbol to be estimated in the time domain d

d=1-3, 5-10, 12-13, k=13, 14, ..., the optimal time-domain interpolation coefficient corresponding to the channel estimation method based on the base extension model at the pilot symbol position corresponding to 612

According to step 2, it can be seen that in the embodiment of the present invention, for

d=1-3, 5-7, k=13, 14, ..., 612 The number of channel estimation values at the corresponding time domain pilot symbol positions M=3, the channel estimation at the corresponding pilot symbol positions The position of the value in the time domain is p ₁ =0, p ₂ =4, p ₃ =11; for

d=8-10, 12-13, k=13, 14, ..., the number of channel estimation values at the corresponding time-domain pilot symbol positions of 612 M=3, the channel estimation at the corresponding pilot symbol positions The positions of the values in the time domain are p ₁ =4, p ₂ =11, p ₃ =14. Substituting the above parameters into the optimal time-domain interpolation coefficient corresponding to the channel estimation method based on the base extension model at the pilot symbol position corresponding to the channel estimation value at the position of the data symbol to be estimated:

${\stackrel{<span\; class="notranslate">\; ^</span>}{\mathrm{<span\; class="notranslate">\; C</span>}}}_{\mathrm{<span\; class="notranslate">\; d</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; optimal</span>}}<span\; class="notranslate">\; =</span>\left[\begin{array}{cccc}{\mathrm{<span\; class="notranslate">\; J</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&pi;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; d</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}}\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; )</span>& {\mathrm{<span\; class="notranslate">\; J</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&pi;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; d</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}}\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; )</span>& <span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span>& {\mathrm{<span\; class="notranslate">\; J</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&pi;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; d</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}}\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; )</span>\end{array}\right]$

$<span\; class="notranslate">\; \&times;</span>{\left[\begin{array}{cccc}\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\frac{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; u</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; e</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; u</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="N"\; filenames="HDA0000055380330000011.png,HDA0000055380330000012.png"\; state="\{\{state\}\}">N</figure-callout></span>}\mathrm{<span\; class="notranslate">\; 1</span>}{\mathrm{<span\; class="notranslate">\; 0</span>}}^{\frac{\mathrm{<span\; class="notranslate">\; SNR</span>}}{\mathrm{<span\; class="notranslate">\; 10</span>}}}}& {\mathrm{<span\; class="notranslate">\; J</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&pi;</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}}\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; )</span>& <span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span>& {\mathrm{<span\; class="notranslate">\; J</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&pi;</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}}\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; )</span>\\ {\mathrm{<span\; class="notranslate">\; J</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&pi;</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}}\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; )</span>& \mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\frac{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; u</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; e</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; u</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>}{{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="10"\; label="N"\; filenames="HDA0000055380330000031.png,HDA0000055380330000041.png"\; state="\{\{state\}\}">N</figure-callout></span>}\mathrm{<span\; class="notranslate">\; 10</span>}}^{\frac{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="10"\; label="SNR"\; filenames="HDA0000055380330000031.png,HDA0000055380330000041.png"\; state="\{\{state\}\}">SNR</figure-callout></span>}}{\mathrm{<span\; class="notranslate">\; 10</span>}}}}& <span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span>& {\mathrm{<span\; class="notranslate">\; J</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&pi;</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}}\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; )</span>\\ <span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span>& <span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span>& <span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span>& <span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span>\\ {\mathrm{<span\; class="notranslate">\; J</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&pi;</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}}\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; )</span>& {\mathrm{<span\; class="notranslate">\; J</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&pi;</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}}\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; )</span>& <span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span>& \mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\frac{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; u</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; e</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; u</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>}{{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="10"\; label="N"\; filenames="HDA0000055380330000031.png,HDA0000055380330000041.png"\; state="\{\{state\}\}">N</figure-callout></span>}\mathrm{<span\; class="notranslate">\; 10</span>}}^{\frac{\mathrm{<span\; class="notranslate">\; SNR</span>}}{\mathrm{<span\; class="notranslate">\; 10</span>}}}}\end{array}\right]}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}$

The normalized Doppler frequency f _D T of the channel can be calculated according to the transmission carrier frequency, transmission bandwidth and moving speed adopted by the wireless mobile communication system. The optimal time-domain interpolation coefficient calculated according to the 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.

k＝13，14，...，612与步骤3中得到的导频符号位置处基于基扩展模型的信道估计方法所对应的最优时间域内插系数d＝1-3，5-10，12-13相乘得到时间域d处待估计数据符号第k个数据子载波位置处信道估计值

d＝1-3，5-10，12-13，k＝13，14，...，612：Step 4, a column vector composed of channel estimation values at the kth subcarrier position of the M pilot symbols obtained in the above step 2 in the time domain

k=13, 14,..., 612 and the optimal time-domain interpolation coefficient corresponding to the channel estimation method based on the base spread model at the pilot symbol position obtained in step 3 d=1-3, 5-10, 12-13 are multiplied to obtain the estimated value of the channel at the kth data subcarrier position of the data symbol to be estimated at the time domain d

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

In Fig. 6 and Fig. 7, the abscissa represents the power ratio (SNR, Signal to Noise Ratio) of the signal and the noise in the channel, and the ordinate represents the block error rate (BLER, Block Error Rate), respectively, the modulation mode in the embodiment of the present invention is At 16QAM and 64QAM, the moving speed is 120 km/h and 350 km/h, according to the parameters in Table 1, the system block error rate performance simulation results under the Extended Vehicular A (EVA) channel specified by LTE. It can be found from the simulation comparison schematic diagram in Fig. 6 that, at a moving speed of 120 km/h and modulation modes of 16QAM and 64QAM, the method proposed in the present invention has a performance improvement of about 1dB compared to the existing LS method. It can be found from the simulation comparison schematic diagram of Fig. 7 that at a moving speed of 350 km/h and a modulation mode of 16QAM, the method of the present invention has a performance improvement of about 2.5 dB compared to the existing LS method; at a moving speed of 350 km/h, Under the modulation mode 64QAM, the method proposed in the present invention has about 3.5dB performance improvement compared with the existing LS method. Therefore, it can be found from the simulation comparison schematic diagrams of Fig. 6 and Fig. 7 that, in the high-speed mobile environment, the method of the present invention has obvious performance improvement compared with the existing method, that is, the channel of the wireless mobile communication system in the high-speed mobile environment is significantly improved. Estimated accuracy.

Those skilled in the art will appreciate that the embodiments described herein are to help readers understand the principles of the present invention, and it should be understood that the protection scope of the invention is not limited to such specific statements and embodiments. All possible equivalent replacements or changes made according to the above description are considered to belong to the protection scope of the claims of the present invention.

Claims (4)

1. a channel estimation method under the high-speed mobile environment, is characterized in that, comprises the steps: Step 1, the transmitting end of the wireless mobile communication system sends a frame signal of a star pilot pattern or a block pilot pattern; Step 2: After receiving the frame signal, the receiving end of the wireless mobile communication system extracts the data at the pilot subcarrier position in the pilot symbol in the frame signal to perform channel estimation based on the base extension model, and obtains the channel estimation value at the position of the data symbol to be estimated A column vector composed of channel estimation values at corresponding pilot symbol positions; Step 3, calculating the optimal time-domain interpolation coefficient corresponding to the channel estimation method based on the base extension model at the pilot symbol position corresponding to the channel estimation value at the position of the data symbol to be estimated; Step 4: Multiply the column vector obtained in step 2 with the optimal time-domain interpolation coefficient obtained in step 3 to obtain an estimated channel value at the position of the data symbol to be estimated. 2. The channel estimation method under the high-speed mobile environment according to claim 1, wherein the channel estimation based on the base extension model described in step 2 utilizes the following formula to obtain the kth data symbol to be estimated at the time domain d place Channel estimates at data subcarrier locations

The channel estimation value at the kth subcarrier position of the corresponding M pilot symbols in the time domain

${\hat{h}}_{p_i}\left(k\right)=\frac{1}{N}\underset{l=0}{\overset{L-1}{\mathrm{\&Sigma;}}}\underset{\mathrm{no}=0}{\overset{N-1}{\mathrm{\&Sigma;}}}\underset{q=0}{\overset{Q}{\mathrm{\&Sigma;}}}{\widehat{\mathrm{\&eta;}}}_{q,l}\left(p_i\right)e^{\frac{j2\mathrm{\&pi;}(q-\frac{Q}{2})\mathrm{no}}{\mathrm{GN}}}{e}^{\frac{-j2\mathrm{\&pi;kl}}{N}},$ k=N _u,s , Nu _,s +1,...,N _u,e ,p _i , i=1,2...,M, where,

Indicates the channel estimate at the position of the kth data subcarrier of the data symbol to be estimated in the time domain d

Corresponding to the channel estimation value at the kth subcarrier position of the pilot symbol at the position p _i in the time domain, η _{q, l} (p _i ) indicates that the pilot symbol at the position p _i in the time domain corresponds to the first path of the lth path of the wireless channel q base extension model coefficients,

Obtained using the data estimation at the pilot subcarrier position in the pilot symbol at position p _i in the time domain, Represents the estimated value of "*", L represents the normalized multipath time delay number of the wireless channel, N represents the number of all subcarriers, Q represents the number of coefficients of the basic extension model used, Q=2r, r= 1, 2, ..., G represents the oversampling coefficient adopted by the base extension model, G≥1 and is a real number, _{Nu, s} represents the starting position of the subcarrier allocated to the user in a pilot symbol or a data symbol , Nu _{, e} represent the end position of the subcarrier allocated to the user in a pilot symbol or a data symbol, (N _{u, e} -N _{u, s} +1) ≤ N, M represents the channel at the position of the data symbol to be estimated The number of channel estimation values at the position of the time-domain pilot symbol corresponding to the estimated value, π represents the circumference ratio,

"∑" indicates a sum operation. Then, the channel estimation value at the kth data subcarrier position of the data symbol to be estimated in the time domain d is obtained

The channel estimation value at the kth subcarrier position of the corresponding M pilot symbols in the time domain A column vector consisting of

k=N _u,s , Nu _,s +1,...,N _u,e , "[] ^T "represents the transposition operation of "[]". 3. the channel estimation method under the high-speed mobile environment according to claim 1, is characterized in that, at the pilot symbol position corresponding to the channel estimation value at the data symbol position to be estimated described in step 3, based on the base extension model The optimal time-domain interpolation coefficient corresponding to the channel estimation method

Calculated according to the following formula: ${\stackrel{<span\; class="notranslate">\; ^</span>}{\mathrm{<span\; class="notranslate">\; C</span>}}}_{\mathrm{<span\; class="notranslate">\; d</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; optimal</span>}}<span\; class="notranslate">\; =</span>\left[\begin{array}{cccc}{\mathrm{<span\; class="notranslate">\; J</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&pi;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; d</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}}\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; )</span>& {\mathrm{<span\; class="notranslate">\; J</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&pi;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; d</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}}\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; )</span>& <span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span>& {\mathrm{<span\; class="notranslate">\; J</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&pi;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; d</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}}\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; )</span>\end{array}\right]$ $<span\; class="notranslate">\; \&times;</span>{\left[\begin{array}{cccc}\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\frac{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; u</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; e</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; u</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; N</span>}\mathrm{<span\; class="notranslate">\; 1</span>}{\mathrm{<span\; class="notranslate">\; 0</span>}}^{\frac{\mathrm{<span\; class="notranslate">\; SNR</span>}}{\mathrm{<span\; class="notranslate">\; 10</span>}}}}& {\mathrm{<span\; class="notranslate">\; J</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&pi;</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}}\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; )</span>& <span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span>& {\mathrm{<span\; class="notranslate">\; J</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&pi;</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}}\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; )</span>\\ {\mathrm{<span\; class="notranslate">\; J</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&pi;</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}}\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; )</span>& \mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\frac{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; u</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; e</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; u</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>}{{\mathrm{<span\; class="notranslate">\; N</span>}\mathrm{<span\; class="notranslate">\; 10</span>}}^{\frac{\mathrm{<span\; class="notranslate">\; SNR</span>}}{\mathrm{<span\; class="notranslate">\; 10</span>}}}}& <span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span>& {\mathrm{<span\; class="notranslate">\; J</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&pi;</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}}\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; )</span>\\ <span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span>& <span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span>& <span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span>& <span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span>\\ {\mathrm{<span\; class="notranslate">\; J</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&pi;</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}}\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; )</span>& {\mathrm{<span\; class="notranslate">\; J</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&pi;</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}}\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; )</span>& <span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span>& \mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\frac{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; u</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; e</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; u</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>}{{\mathrm{<span\; class="notranslate">\; N</span>}\mathrm{<span\; class="notranslate">\; 10</span>}}^{\frac{\mathrm{<span\; class="notranslate">\; SNR</span>}}{\mathrm{<span\; class="notranslate">\; 10</span>}}}}\end{array}\right]}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; ,</span>$

In order to minimize the mean square estimation error, the optimal time-domain interpolation coefficient corresponding to the channel estimation method based on the base extension model at the pilot symbol position corresponding to the channel estimation value at the position of the data symbol to be estimated given by the present invention, where , J ₀ (*) represents the 0th order Bessel function, f _D T is the normalized Doppler frequency of the channel, π represents the circular ratio, SNR represents the power ratio of signal to noise in the channel, and d represents the data symbol to be estimated Positions in the time domain, p _i , i=1, 2..., M represents the channel estimation values at the M pilot symbol positions corresponding to the channel estimation values of the data symbols to be estimated at position d in the time domain at time The position of the field, "×" indicates matrix multiplication operation, "+" indicates scalar addition operation, and "[] ^-1 "indicates matrix inversion operation. 4. according to the channel estimation method under any high-speed mobile environment described in claim 1 to 3, it is characterized in that, the pilot frequency sub-carrier in the frame signal described in the step 1 is evenly distributed in the pilot symbol at equal intervals, the pilot frequency The insertion period T _f of subcarriers in pilot symbols satisfies

τ _L Δf is the maximum normalized multipath delay of the channel, and the insertion interval T _t of pilot symbols in the frame signal satisfies

f _D T is the normalized Doppler frequency of the channel,

Indicates the floor operation of "*".

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