CN101488936A - Wireless transmission system, receiver thereof and inter-carrier interference elimination method thereof - Google Patents

Abstract

An inter-carrier interference elimination method is used for eliminating inter-carrier interference of a received cell. First, a transmitted cell is received through a wireless channel within a cell time to obtain a received cell. The transmission cell includes P identical original portions of data. The received cell includes P received partial data, which respectively correspond to the original partial data. Then, at least two of the P received partial data are copied in the time domain to obtain at least two copied partial data. Each replicated partial data includes P copies of its corresponding received partial data. P is a positive integer greater than 1. And determining the estimated intercarrier interference in the time domain according to the product of the difference of the subtraction of the at least two copied parts of data and the constant sequence. Then, the estimated intercarrier interference is subtracted from the received cell to obtain an output cell.

Description

Wireless transmission system, method for eliminating interference between its receiver and its carrier

technical field

The present invention relates to a method for estimating and eliminating interference between cell carriers, and in particular to a method for estimating and eliminating interference between cell carriers with low complexity in time domain.

Background technique

In recent years, Orthogonal frequency division multiplexing (OFDM) communication technology has been widely used in communication systems. In order to be suitable for transmitting data in the wireless channel environment, the system lengthens its cell time and increases the cyclic prefix (CP) to combat the multipath delay spread of the wireless channel. However, because of the long cell time, the system is very sensitive to carrier frequency offset. In a mobile environment, the radio channel environment changes over time. When the speed is very fast, the wireless channel will become unstable within a cell time, and this time-varying channel will destroy the orthogonality of the cell, and generate Doppler spread in the frequency domain, causing the reception Inter-Carrier Interference (ICI) at the end.

In order to overcome the problem of inter-carrier interference, many methods of inter-carrier interference cancellation have been proposed. Such methods can be roughly divided into two categories. In the first type of method, it is mainly divided into two stages to eliminate inter-carrier interference of cells. The first stage is mainly for time-varying channel estimation, and the second stage is for interference elimination. The time-varying channel can be estimated by the specially designed time-domain pilot signal or frequency-domain pilot signal (pilot), and then use the linear Or a non-linear cell detection method for carrier value detection and interference elimination.

Another type of method is called inter-carrier interference self-cancellation scheme (Inter-carrier interference self-cancellation scheme). In this method, the transmitting end modulates the original carrier to be transmitted to several adjacent and staggered forward and reverse polarity (anti-polar) carriers. Each original carrier is mapped to a group of positive and reverse polarity carriers. When receiving, directly multiply each positive polarity and reverse polarity carrier by a positive and negative sign and then combine them to achieve the purpose of self-elimination of inter-carrier interference. In this method, since each original carrier corresponds to a group of forward and reverse polarity carriers, the efficiency of spectrum usage will be reduced several times.

Contents of the invention

The object of the present invention is to provide a wireless transmission system, its receiver and a method for eliminating interference between carriers.

The invention relates to a method for estimating and eliminating inter-carrier interference with low complexity in the time domain. Utilize the data with repetitive characteristics in the cells, and apply the inter-carrier interference elimination method of the embodiment of the present invention, as long as simple addition and multiplication operations are performed, the inter-carrier interference received by the received cells can be effectively estimated and eliminated . In other examples of the present invention, the transmitting end may apply a cyclic prefix data length configuration method, and the receiving end may apply the ICI elimination method of the embodiment of the present invention, which can effectively remove most of the ICI.

According to a first aspect of the exemplary embodiments of the present invention, a method for eliminating ICI is provided, which is used for eliminating Inter-carrier interference (ICI) of a received symbol. The method includes the following steps. Firstly, the transmission cell is received through the wireless channel within the cell time to obtain the received cell. A transport cell includes P identical original partial data. The received cell includes P pieces of received partial data, respectively corresponding to the above-mentioned original partial data. Next, copy at least two of the P received partial data in the time domain to obtain at least two copied partial data. Each replicated partial data includes P copies of its corresponding received partial data. P is a positive integer greater than 1. After that, it is determined to estimate the inter-carrier interference according to the product of the subtraction difference of the at least two replicated partial data and the constant sequence. Then subtract the estimated inter-carrier interference from the received cells to obtain the output cells.

According to a second aspect of an example of the present invention, a receiver is provided for receiving a transmission cell generated by a transmitter through a wireless channel within a cell time, obtaining a received cell, and canceling Intercarrier interference of received cells. A transport cell includes P original partial data. Each original partial data includes several original time-domain sample data. Each raw part data is the same. The received cell includes several received partial data, corresponding to the original partial data respectively. The receiver includes a data synchronization module, an ICI estimation module, an ICI removal module, a FFT, and a demodulator. The data synchronization module synchronizes the received cells. The ICI estimating module replicates at least two of the P received partial data in the time domain to obtain at least two replicated partial data. Each replicated partial data includes P copies of its corresponding received partial data. P is a positive integer greater than 1. The inter-carrier interference estimating module determines an estimated inter-carrier interference according to a product of a subtraction difference of at least two replicated partial data and a constant sequence. The ICI removing module subtracts the estimated ICI from the received symbol to obtain an output symbol. The FFT transforms the output cells into a frequency domain. The demodulator demodulates the output in the frequency domain.

According to a third aspect of the examples of the present invention, a wireless transmission system is provided, including a transmitter and a receiver. The transmitter generates and transmits a transport symbol in the time domain. A transport cell includes P original partial data. Each original partial data includes several original time-domain sample data. The data is the same per original received part. The receiver receives transmission cells through a wireless channel within a cell time to obtain a received cell. The received cell includes P pieces of received partial data, which respectively correspond to P pieces of original partial data. The receiver includes a data synchronization module, an ICI estimation module, an ICI removal module, a FFT, and a demodulator. The data synchronization module is used to synchronize the received cells. The ICI estimating module replicates at least two of the P received partial data in the time domain to obtain at least two replicated partial data. Each replicated partial data includes P copies of its corresponding received partial data. P is a positive integer greater than 1. The inter-carrier interference estimating module determines an estimated inter-carrier interference according to a product of a subtraction difference of at least two replicated partial data and a constant sequence. The ICI removing module subtracts the estimated ICI from the received symbol to obtain an output symbol. The FFT transforms the output cells into a frequency domain. The demodulator demodulates the output in the frequency domain.

According to a fourth aspect of the exemplary embodiments of the present invention, an ICI cancellation method is provided for canceling the ICI of a received symbol. The method includes the following steps. Firstly, a transmission symbol generated by a transmitter is received through a wireless channel within a cell time to obtain a received symbol. The transport cell includes an original data cell and a cyclic prefix. The cyclic preamble data is the same as the post data of the original data cell. The received cells correspondingly include a received data cell and a received cyclic prefix data, respectively corresponding to the original data cell and the cyclic prefix data. A received back-end data of the received data cells corresponds to back-end data. Next, an estimated ICI is determined according to a product of a difference between at least a part of the received cyclic prefix data and at least a part of the received post data and a constant sequence. Afterwards, the estimated ICI is subtracted from the received symbols to obtain an output symbol.

According to a fifth aspect of the examples of the present invention, a wireless transmission system is provided, including a transmitter and a receiver. The transmitter generates and transmits a transport symbol in the time domain. The transmission cell is a cell, including an original data cell and a cyclic prefix. The cyclic prefix data is the same as an original post data of the original data cell. The receiver receives transmission cells through a wireless channel within a cell time to obtain a received cell. The received cells correspondingly include a received data cell and a received cyclic prefix data, respectively corresponding to the original data cell and the cyclic prefix data. A received back-end data of the received data cells corresponds to back-end data. The receiver includes a data synchronization module, an ICI estimation module, an ICI removal module, a FFT, and a demodulator. The data synchronization module synchronizes the received cells. The inter-carrier interference estimation module determines an estimated inter-carrier interference according to a product of a difference between at least part of the received cyclic preamble data and at least part of the received back-end data and a constant sequence. The ICI removing module subtracts the estimated ICI from the received symbol to obtain an output symbol. The FFT transforms the output cells into a frequency domain. The demodulator demodulates the output in the frequency domain.

According to a sixth aspect of the examples of the present invention, a method for eliminating inter-carrier interference is provided, including the following steps. Firstly, a transmission symbol generated by a transmitter is received through a wireless channel within a cell time to obtain a received symbol. The transport cell includes at least two identical original portions of data. The received cell includes at least two corresponding received partial data, respectively corresponding to the above two original partial data. Afterwards, an estimated inter-carrier interference is determined according to a product of a subtraction difference of at least two received partial data and a constant sequence. Next, the estimated ICI is subtracted from the received symbol to obtain an output symbol.

According to the seventh aspect of the example of the present invention, a method for configuring the length of cyclic prefix data is provided, which is applicable to a communication system, wherein the communication system includes at least one transmission cell, and the transmission cell includes a cyclic prefix data and a data signal element, the method includes: configuring the length of the cyclic prefix data to be greater than or equal to half of the length of the data cell.

According to an eighth aspect of the examples of the present invention, a transmitter is provided, suitable for a communication system, for generating and transmitting a transmission cell in the time domain, the transmission cell includes an original data cell and a cyclic prefix data , the cyclic prefix data is the same as an original post data of the original data cell, wherein the length of the cyclic prefix data is greater than or equal to half of the length of the original data cell.

According to a ninth aspect of the examples of the present invention, a wireless transmission system is provided, including a transmitter and a receiver. The transmitter is used to generate and transmit a transmission symbol in the time domain, including an original data symbol and a cyclic prefix data. The cyclic prefix data is the same as an original rear data of the original data symbol, wherein the cyclic prefix Set the length of the data to be greater than or equal to half of the length of the original data cell. The receiver receives the above-mentioned transmission cells through a wireless channel within one cell time to obtain a received cell, which correspondingly includes a received data cell and a received cyclic prefix data, respectively Corresponding to the original data cell and the cyclic prefix data, a received back-end data of the received data cell corresponds to the above-mentioned original back-end data.

In order to make the above content of the present invention more comprehensible, preferred embodiments are specifically cited below and described in detail in conjunction with the accompanying drawings.

Description of drawings

FIG. 1 shows a flow chart of the method for eliminating inter-carrier interference in this embodiment.

FIG. 2 shows a block diagram of the wireless transmission system of this embodiment.

FIG. 3 shows a flow chart of the method for eliminating ICI in the first embodiment.

FIG. 4 shows a detailed schematic diagram of steps 330 and 340 in FIG. 3 .

FIG. 5A shows an example of the change diagram of the channel response within one cell time when the transmission cell is transmitted in the first embodiment.

Figure 5B shows a schematic diagram of a linear approximation of the channel response of Figure 5A.

FIG. 5C shows a schematic diagram of the channel response to the replicated portion of data corresponding to FIG. 5B .

FIG. 5D shows a schematic diagram of the channel response to another replicated partial data corresponding to FIG. 5B .

FIG. 6A shows another example of the change diagram of the channel response within one cell time in the first embodiment.

Figure 6B shows a schematic diagram of the channel response to replicated partial data.

Figure 6C shows a schematic diagram of the channel response to replicated partial data.

Fig. 7 shows a block diagram of the transmitter of the first embodiment.

FIG. 8 shows an example of adjusted frequency data after adjustment.

FIG. 9 shows a flow chart of the method for eliminating ICI in the second embodiment.

FIG. 10 shows an example of the change diagram of the channel response within one cell time when the transmission cell is transmitted in the second embodiment.

Fig. 11 shows a block diagram of the transmitter of the second embodiment.

Figure 12 shows that when the transmission symbol has repeated data, the Doppler spread and the inter-carrier interference obtained by applying the inter-carrier interference elimination method of this embodiment, the traditional inter-carrier interference self-elimination method and not using any inter-carrier interference elimination method An example of a relationship diagram between disturbance energies.

Fig. 13 shows that when the transmission symbol has repeated data, the real part (Real part) of the intercarrier interference actually received by the received symbol and the estimated carrier estimated by the method for eliminating intercarrier interference according to the present embodiment Relationships between real parts.

Fig. 14 shows that when the transmission symbol has repeated data, the imaginary part (Image part) of the intercarrier interference actually received by the received symbol and the estimated carrier estimated by the method for eliminating intercarrier interference according to this embodiment Relationships between imaginary parts.

FIG. 15 shows an example of channel estimation mean square error (MSE) of the transmitted 802.16e preamble data under different Doppler spreads and different Gaussian noise intensities.

FIG. 16 shows an example of the relationship between the ICI and the Doppler spread suffered by the received symbol when the transmitted symbol is a cell with different lengths of cyclic prefix data.

Explanation of main component symbols in the attached drawings:

100: Teleporter

110, 110': modulator

120, 120’: subcarrier adjustment module

130, 130': Inverse Fast Fourier Transformer (IFFT)

200: Receiver

210: data synchronization module

220: Inter-carrier interference estimation module

230: Inter-carrier interference removal module

240: Fast Fourier Transformer (FFT)

250: Demodulator

300: wireless channel

Detailed ways

The inter-carrier interference elimination method of the embodiment of the present invention is to estimate the inter-carrier interference generated by the symbol by using the data with repetitive characteristics in the time domain of the transmitted symbol and the different responses generated by passing through the time-varying channel. FIG. 1 shows a flow chart of the method for eliminating inter-carrier interference proposed in this embodiment. First, in step 10, the transmission cell generated by the transmitter is received through the wireless channel within a cell time to obtain a received cell. The cells generated by the transmitter include at least two repetitions of the original partial data in the time domain. When receiving, take out the result of the time-varying channel response to obtain the received cell. Wherein, the received cell includes at least two corresponding received partial data, respectively corresponding to the above two repeated original partial data. Next, in step 20, an estimated inter-carrier interference is determined according to the product of the subtraction difference of the at least two received partial data and a constant sequence. Afterwards, in step 30, subtract the estimated ICI from the received time-domain signal of the symbol to obtain an output symbol with ICI eliminated.

FIG. 2 shows a block diagram of the wireless transmission system of this embodiment. As shown in FIG. 2 , the wireless transmission system of this embodiment includes a transmitter 100 and a receiver 200 . The transmitter 100 of this embodiment generates and transmits a transport symbol Dt. Wherein, the transmission symbol Dt generated by the transmitter 100 includes at least two repeated original partial data Dprt in the time domain.

The receiver 200 of this embodiment includes a data synchronization module 210 , an ICI estimation module 220 , an ICI removal module 230 , a Fast Fourier Transformer (FFT) 240 and a demodulator 250 . The receiver 200 implements the ICI cancellation method shown in FIG. 1 . According to different data repetition patterns in transmission cells, two embodiments are used to illustrate the operation of the transmitter and receiver in FIG. 2 . In the two embodiments, the transmitter and the receiver in FIG. 2 are applied to Orthogonal frequency division multiplexing (OFDM) communication technology as an example for illustration.

first embodiment

个原始时域取样资料。亦即，传输信元具有P个重复数据。接收器200通过无线通道300接收传输信元Dt，得到一已接收信元。已接收信元先经过数据同步模块210处理后得到同步的已接收信元Dr。已接收信元Dr包括N个已接收时域取样数据，分为P个已接收部分数据Dprt’，分别对应传输信元Dt中的P个原始部分数据Dprt。In the first embodiment, the transmission symbol Dt generated by the transmitter 100 includes N time domain sample data. The N original time-domain sampling data are divided into P repeated original partial data Dprt, where P is a positive integer greater than 1. Each raw part data Dprt includes

original time-domain sampling data. That is, the transport cell has P repeated data. The receiver 200 receives the transmission cell Dt through the wireless channel 300 to obtain a received cell. The received cells are firstly processed by the data synchronization module 210 to obtain synchronized received cells Dr. The received cell Dr includes N received time-domain sampled data, divided into P received partial data Dprt', corresponding to P original partial data Dprt in the transmitted cell Dt.

Fig. 3 shows a flow chart of the method for eliminating ICI in the first embodiment. The ICI cancellation method of the first embodiment is applied to the receiver 200 . Please refer to Figure 2 and Figure 3 at the same time. In step 310, the data synchronization module 210 receives the transmission cell Dt through the wireless channel 300 within one cell time to obtain the received cell Dr. The data synchronization module 210 performs time and frequency synchronization on the received cell Dr, and outputs the synchronized received cell Dr.

Next, in step 320, the intercarrier interference estimation module 220 takes out P received partial data Dprt' in the time domain, takes out at least two partial data Dprt', and copies different Dprt' in the time domain to obtain at least Two copy part data Dcpy. Each duplicate received partial data Dcpy comprises P copies of its corresponding received partial data Dprt'.

Afterwards, in step 330 , the ICI estimating module 220 determines an estimated ICI Dici according to the product of the subtraction difference of the at least two copied partial data Dcpy and a constant sequence.

Next, in step 340 , the ICI removal module 230 subtracts the estimated ICI Dici from the received symbol Dr to obtain an output symbol Dout without ICI.

After removing the estimated inter-carrier interference Dici, the FFT 240 transforms the output cell Dout to the frequency domain. The demodulator 250 demodulates the signal in the frequency domain.

行，其它元素系为0。有关上述复制的操作将于之后详述。Wherein, in step 320, in order to copy the received partial data Dprt', the ICI estimating module 220 multiplies the received symbol Dr by at least two of the P window matrices (Window matrix). If the received cell Dr is multiplied by the i-th window matrix W _i , the copied partial data Dcpy(i) can be generated. Wherein, the copied partial data Dcpy(i) includes P copies of the i-th received partial data Dprt'(i). Wherein, i is a positive integer less than or equal to P. The size of each window matrix is N×N, including P unit matrices, and the size of each unit matrix is In the i-th window matrix W _i , the first row of each identity matrix is located in the i-th window matrix

row, other elements are 0. The operation of the above-mentioned copying will be described in detail later.

FIG. 4 shows a detailed schematic diagram of step 330 and step 340 . Please refer to Figure 3 and Figure 4. Step 330 includes two sub-steps 410 and 420 . In step 410, the ICI estimating module 220 first generates the subtraction difference of the at least two copied partial data Dcpy. Next, in sub-step 420 of step 330 , the ICI estimating module 220 multiplies the subtracted difference by a constant sequence to obtain the estimated ICI Dici. This constant sequence is the diagonal sequence of the diagonal matrix C. In one example, C is an N×N matrix, and the elements in column i and row j are

$C(i,j)=\left\{\begin{array}{cc}\frac{P}{(P-a)\&times;N}(i-\frac{N-1}{2})& i=\mathrm{<figure-callout\; id="0"\; label="j"\; filenames="A200810093195E00471.png,A200810093195E00481.png"\; state="\{\{state\}\}">j</figure-callout>}\\ 0& \mathrm{<figure-callout\; id="1"\; label="else\; Form"\; filenames="A200810093195E00441.png,A200810093195E00442.png"\; state="\{\{state\}\}">else</figure-callout>}& \\ \end{array},\right.$ Form 1

Wherein, i and j are positive integers less than or equal to N, and a is a positive integer less than P.

The principle of steps 320 to 350 will be described in detail. Firstly, the system model applied by the method for eliminating inter-carrier interference in this embodiment will be described. As stated in Equation 2, the transmission cell Dt generated by the transmitter 100 has a relationship with the received cell Dr after passing through the wireless channel 300 and the synchronization module 210 .

$\begin{array}{cc}{\mathrm{the\; y}}_i=\underset{k=0}{\overset{L-1}{\mathrm{\&Sigma;}}}{h}_k^{\left(i\right)}{x}_{{\left((i-k)\right)}_N}+{\mathrm{no}}_i,& 0\&le;i\&le;N-1\end{array}$ Form 2

为无线通道300中，第k个路径在第i个时间点的时域通道响应。n_i表示在第i个时间点的高斯噪声(Additive white Gaussian noise，AWGN)。Where N is the number of carriers, L is the number of effective paths of the wireless channel 300, and y _i is the i-th received time-domain sampled data of the N received time-domain sampled data in the received cell Dr. x _ik is the ik-th original time-domain sampling data in the transmission symbol Dt generated by the transmitter 100 .

is the time-domain channel response of the k-th path at the i-th time point in the wireless channel 300 . n _i represents the Gaussian noise (Additive white Gaussian noise, AWGN) at the i-th time point.

Write the second formula in matrix form (matrix form), you can get the third formula:

$\stackrel{\&Right\; Arrow;}{\mathrm{the\; y}}=h\stackrel{\&Right\; Arrow;}{x}+\stackrel{\&Right\; Arrow;}{\mathrm{no}}$ Form 3

系已接收信元Dr。

为N×1矩阵，其第i列元素(Entry)等于第2式的y_i。

为传送器100的传输信元Dt的数列，

为N×1矩阵，其第i列元素等于第2式的x_i。为高斯噪声数列，为N×1矩阵，其第i列元素等于第二式的n_i。H为无线通道300的时间响应矩阵，其第i列的第j行元素H(i，j)等于第二式的

in,

The line has received the cell Dr.

It is an N×1 matrix, and its i-th column element (Entry) is equal to y _i in the second formula.

is the sequence of transmission cells Dt of the transmitter 100,

It is an N×1 matrix, and its i-th column element is equal to x _i in the second formula. is a Gaussian noise sequence, an N×1 matrix, and its i-th column element is equal to n _i in the second formula. H is the time response matrix of the wireless channel 300, and the element H (i, j) of the jth row of its i column is equal to that of the second formula

FIG. 5A shows the channel response of a certain path over time for the wireless channel 300 in a mobile environment. When the moving speed of the receiver 200 is not very high, as shown in FIG. 5B , the change of the channel response within one cell time T _s can be approximately linear (Linear approximation).

Therefore, the channel response of the k-th path and the i-th time can be approximated as formula 4:

$h_k^{\left(i\right)}\&ap;h_k^{\left(\frac{N-1}{2}\right)}+((i-\frac{N-1}{2})/(N-1))\&Center\; Dot;{\mathrm{\&alpha;}}_k$ Form 4

Among them, α _k represents the amount of change between the first and the last of the kth path in the cell time T _s , so

${\mathrm{\&alpha;}}_k=h_k^{(N-1)}-h_k^{\left(0\right)}$ Form 5

Substituting Equation 4 and Equation 5 into Equation 3, we can get

$\stackrel{\&Right\; Arrow;}{\mathrm{the\; y}}\&ap;h_{\mathrm{middle}}\stackrel{\&Right\; Arrow;}{x}+m\&times;A\&times;\stackrel{\&Right\; Arrow;}{x}+\stackrel{\&Right\; Arrow;}{\mathrm{no}}$ Formula 6, where,

$h_{\mathrm{middle}}(i,j)=h_{{\left((i-j)\right)}_N}^{\left(\frac{N-1}{2}\right)}$ 0≤i, j≤N-1 Formula 7

$A(i,j)={\mathrm{\&alpha;}}_{{\left((i-j)\right)}_{\mathrm{<figure-callout\; id="0"\; label="N"\; filenames="A200810093195E00471.png,A200810093195E00481.png"\; state="\{\{state\}\}">N</figure-callout>}}}$ 0≤i, j≤N-1 Formula 8

$m(i,j)=\left\{\begin{array}{cc}(i-\frac{N-1}{2})/(N-1)& ,i=\mathrm{<figure-callout\; id="0"\; label="j"\; filenames="A200810093195E00471.png,A200810093195E00481.png"\; state="\{\{state\}\}">j</figure-callout>}\\ 0& ,\mathrm{else}\end{array}\right.$ Formula 9

The second item on the right side of the equation in Equation 6 is the time-domain inter-carrier interference Dici to be estimated and eliminated, namely:

${\stackrel{\&Right\; Arrow;}{e}}_{\mathrm{ici}}\&ap;m\&times;A\&times;\stackrel{\&Right\; Arrow;}{x}$ Form 10

越大。From formula 8, it can be seen that when the speed is faster, the change of channel response α _k is greater, therefore, the value of A matrix is larger, resulting in the inter-carrier interference in formula 10

bigger.

即为在信元时间T_s内未受到载波间干扰影响的部分。The H _mid of the first item on the right side of Equation 6 can be regarded as the average approximate value of the channel response corresponding to the cell time T _s , that is, the channel response at the midpoint of the cell time T _s in FIG. 5B .

That is, the part that is not affected by inter-carrier interference within the cell time T _s .

After explaining the system model, the steps 320 to 340 are explained by taking the transmission cell Dt generated by the transmitter 100 including two repeated original partial data Dprt, ie P equals 2, as an example.

在信元时间T_s内为线性近似，α_k亦可以表示为：when

It is a linear approximation within the cell time T _s , and α _k can also be expressed as:

${\mathrm{<span\; class="notranslate">\; \&alpha;</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; )</span>}$

$=(h_k^{\left(\frac{N-1}{4}\right)}-h_k^{\left(\frac{3N-3}{4}\right)})\&times;\frac{2(N-1)}{N}$ Form 11

为时间点

时，第k个路径的通道响应，即前半段信元时间T_s1内的平均通道响应。而

为时间点时，第k个路径的通道响应，即后半段信元时间T_s2内的平均通道响应。In formula 11,

for time point

When , the channel response of the kth path is the average channel response in the first half of the cell time T _s1 . and

for time point When , the channel response of the kth path is the average channel response in the second half of the cell time T _s2 .

Substituting Equation 11 into Equation 10, we get:

${\stackrel{\&Right\; Arrow;}{e}}_{\mathrm{ici}}\&ap;\frac{2(N-1)}{N}\&times;m\&times;(h_2-h_1)\&times;\stackrel{\&Right\; Arrow;}{x}$ Form 12

in,

$h_2(i,j)=h_{{\left((i-j)\right)}_N}^{\left(\frac{3N-3}{4}\right)},0\&le;i,j\&le;N-1$ Form 13

$h_1(i,j)=h_{{\left((i-j)\right)}_N}^{\left(\frac{N-1}{4}\right)},0\&le;i,j\&le;N-1$ Form 14

即可估测出估测载波间干扰

As shown in FIG. 5B , the twelfth formula uses the average channel response H ₁ of the wireless channel 300 in the first half of the cell time T _s1 and the average channel response H ₂ of the second half of the cell time T _s2 to estimate the ICI. Observing formula 12, we can see that since N and matrix M are known, if we get

Intercarrier Interference

可以分别以

与为作为基准点来进行线性近似。因此，已接收信元

可以分别改写为：Based on this idea, similar to formula 4, the wireless channel response

can be separately

and As a reference point for linear approximation. Therefore, the received cell

can be rewritten as:

$\stackrel{\&Right\; Arrow;}{\mathrm{the\; y}}\&ap;h_2\stackrel{\&Right\; Arrow;}{x}+{\mathrm{<figure-callout\; id="2"\; label="m"\; filenames="A200810093195E00452.png,A200810093195E00481.png"\; state="\{\{state\}\}">m</figure-callout>}}_2\&times;A\&times;\stackrel{\&Right\; Arrow;}{x}+\stackrel{\&Right\; Arrow;}{\mathrm{no}}$ Form 15

$\stackrel{\&Right\; Arrow;}{\mathrm{the\; y}}\&ap;h_1\stackrel{\&Right\; Arrow;}{x}+{\mathrm{<figure-callout\; id="1"\; label="m"\; filenames="A200810093195E00441.png,A200810093195E00442.png"\; state="\{\{state\}\}">m</figure-callout>}}_1\&times;A\&times;\stackrel{\&Right\; Arrow;}{x}+\stackrel{\&Right\; Arrow;}{\mathrm{no}}$ Form 16

in,

$m_2(i,j)=\left\{\begin{array}{cc}i-\left(\frac{3N-2}{4}\right)/(N-1)& i=j,0\&le;i,j\&le;N-1\\ 0& \mathrm{else}\end{array}\right.$ Form 17

$m_1(i,j)=\left\{\begin{array}{cc}i-\left(\frac{N-2}{4}\right)/(N-1)& i=j,0\&le;i,j\&le;N-1\\ 0& \mathrm{else}\end{array}\right.$ Form 18

The matrices M ₁ and M ₂ of formula 17 and formula 18 have the following relationship:

$m_1(i,i)=m_2(i+\frac{\mathrm{<figure-callout\; id="2"\; label="N"\; filenames="A200810093195E00452.png,A200810093195E00481.png"\; state="\{\{state\}\}">N</figure-callout>}}{2},i+\frac{N}{2})$ Form 19

In this example, the transmission cell Dt has two identical original partial data Dprt(1) and Dprt(2), namely:

$\stackrel{\&Right\; Arrow;}{x}=\left[\begin{array}{c}{\stackrel{\&Right\; Arrow;}{x}}_1\\ {\stackrel{\&Right\; Arrow;}{x}}_2\end{array}\right]$ Form 20

至

分别为第1个与第2个原始部分资料Dprt(1)与Dprt(2)。在本例中， ${\stackrel{\&RightArrow;}{x}}_1={\stackrel{\&RightArrow;}{x}}_2.$ In formula 20,

to

They are the first and second original partial data Dprt(1) and Dprt(2) respectively. In this example, ${\stackrel{\&Right\; Arrow;}{x}}_1={\stackrel{\&Right\; Arrow;}{x}}_2.$

乘以第1个窗矩阵W₁，得到第1个复制部分数据Dcpy(1)。如第21式所示：Therefore, in step 320, the intercarrier interference estimation module 220 uses the received symbol Dr, namely

Multiply by the first window matrix W ₁ to get the first copied part data Dcpy(1). As shown in formula 21:

${\stackrel{\&Right\; Arrow;}{\mathrm{the\; y}}}_1={\mathrm{<figure-callout\; id="1"\; label="W"\; filenames="A200810093195E00441.png,A200810093195E00442.png"\; state="\{\{state\}\}">W</figure-callout>}}_1\&times;\stackrel{\&Right\; Arrow;}{\mathrm{the\; y}}={\mathrm{<figure-callout\; id="1"\; label="W"\; filenames="A200810093195E00441.png,A200810093195E00442.png"\; state="\{\{state\}\}">W</figure-callout>}}_1\&times;{\mathrm{<figure-callout\; id="1"\; label="h"\; filenames="A200810093195E00441.png,A200810093195E00442.png"\; state="\{\{state\}\}">h</figure-callout>}}_1\&times;\stackrel{\&Right\; Arrow;}{x}+{\mathrm{<figure-callout\; id="1"\; label="W"\; filenames="A200810093195E00441.png,A200810093195E00442.png"\; state="\{\{state\}\}">W</figure-callout>}}_1\&times;{\mathrm{<figure-callout\; id="1"\; label="m"\; filenames="A200810093195E00441.png,A200810093195E00442.png"\; state="\{\{state\}\}">m</figure-callout>}}_1\&times;A\&times;\stackrel{\&Right\; Arrow;}{x}+{\mathrm{<figure-callout\; id="1"\; label="W"\; filenames="A200810093195E00441.png,A200810093195E00442.png"\; state="\{\{state\}\}">W</figure-callout>}}_1\&times;\stackrel{\&Right\; Arrow;}{\mathrm{no}}$ Form 21

乘以W₁。

包括对应第1个已接收部分数据Dprt’(1)的2个拷贝。其中，In the 21st formula, the 16th formula

Multiply by W ₁ .

Contains 2 copies corresponding to the first received partial data Dprt'(1). in,

${\mathrm{<figure-callout\; id="1"\; label="W"\; filenames="A200810093195E00441.png,A200810093195E00442.png"\; state="\{\{state\}\}">W</figure-callout>}}_1=\left[\begin{array}{cc}{\mathrm{<figure-callout\; id="2"\; label="I\; N"\; filenames="A200810093195E00452.png,A200810093195E00481.png"\; state="\{\{state\}\}">I</figure-callout>}}_{\frac{N}{}}& 0_{\frac{\mathrm{<figure-callout\; id="2"\; label="N"\; filenames="A200810093195E00452.png,A200810093195E00481.png"\; state="\{\{state\}\}">N</figure-callout>}}{2}\&times;\frac{N}{2}}\\ {\mathrm{<figure-callout\; id="2"\; label="I\; N"\; filenames="A200810093195E00452.png,A200810093195E00481.png"\; state="\{\{state\}\}">I</figure-callout>}}_{\frac{N}{}}& 0_{\frac{\mathrm{<figure-callout\; id="2"\; label="N"\; filenames="A200810093195E00452.png,A200810093195E00481.png"\; state="\{\{state\}\}">N</figure-callout>}}{2}\&times;\frac{\mathrm{<figure-callout\; id="2"\; label="N"\; filenames="A200810093195E00452.png,A200810093195E00481.png"\; state="\{\{state\}\}">N</figure-callout>}}{2}}\end{array}\right]$ Form 22

的单位矩阵

其它元素为0。在第1个窗矩阵W₁，即i＝1，中，每个单位矩阵I的第1行位于窗矩阵W₁的第1行，即行，其它元素为0。In this example, P equals 2. Therefore, the size of W ₁ is N×N, including 2 sizes of

the identity matrix of

The other elements are 0. In the first window matrix W ₁ , that is, i=1, the first row of each identity matrix I is located in the first row of the window matrix W ₁ , that is line, other elements are 0.

所受的通道响应的示意图。图5C中，复制部分数据

中的两个拷贝所受的平均通道响应均等于H₁。Figure 5C shows the replicated partial data

Schematic representation of the subjected channel response. Figure 5C, copy part of the data

The average channel response experienced by both copies in is equal to H ₁ .

乘以第2个窗矩阵W₂，得到第2个复制部分数据Dcpy(2)。如第23式所示：Similarly, the intercarrier interference estimation module 220 will

Multiply by the second window matrix W ₂ to get the second copied part data Dcpy(2). As shown in formula 23:

${\stackrel{\&Right\; Arrow;}{\mathrm{the\; y}}}_2={\mathrm{<figure-callout\; id="2"\; label="W"\; filenames="A200810093195E00452.png,A200810093195E00481.png"\; state="\{\{state\}\}">W</figure-callout>}}_2\&times;\stackrel{\&Right\; Arrow;}{\mathrm{the\; y}}={\mathrm{<figure-callout\; id="2"\; label="W"\; filenames="A200810093195E00452.png,A200810093195E00481.png"\; state="\{\{state\}\}">W</figure-callout>}}_2\&times;{\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="A200810093195E00452.png,A200810093195E00481.png"\; state="\{\{state\}\}">h</figure-callout>}}_2\&times;\stackrel{\&Right\; Arrow;}{x}+{\mathrm{<figure-callout\; id="2"\; label="W"\; filenames="A200810093195E00452.png,A200810093195E00481.png"\; state="\{\{state\}\}">W</figure-callout>}}_2\&times;{\mathrm{<figure-callout\; id="2"\; label="m"\; filenames="A200810093195E00452.png,A200810093195E00481.png"\; state="\{\{state\}\}">m</figure-callout>}}_2\&times;A\&times;\stackrel{\&Right\; Arrow;}{x}+{\mathrm{<figure-callout\; id="2"\; label="W"\; filenames="A200810093195E00452.png,A200810093195E00481.png"\; state="\{\{state\}\}">W</figure-callout>}}_2\&times;\stackrel{\&Right\; Arrow;}{\mathrm{no}}$ Form 23

乘以W₂。

包括对应第2个已接收部分数据Dprt’(2)的2个拷贝。其中，In the 23rd formula, the 15th formula

Multiply by W ₂ .

Contains 2 copies corresponding to the 2nd received partial data Dprt'(2). in,

${\mathrm{<figure-callout\; id="2"\; label="W"\; filenames="A200810093195E00452.png,A200810093195E00481.png"\; state="\{\{state\}\}">W</figure-callout>}}_2=\left[\begin{array}{cc}{0}_{\frac{\mathrm{<figure-callout\; id="2"\; label="N"\; filenames="A200810093195E00452.png,A200810093195E00481.png"\; state="\{\{state\}\}">N</figure-callout>}}{2}\&times;\frac{N}{2}}& {\mathrm{<figure-callout\; id="2"\; label="I\; N"\; filenames="A200810093195E00452.png,A200810093195E00481.png"\; state="\{\{state\}\}">I</figure-callout>}}_{\frac{N}{}}\\ 0_{\frac{\mathrm{<figure-callout\; id="2"\; label="N"\; filenames="A200810093195E00452.png,A200810093195E00481.png"\; state="\{\{state\}\}">N</figure-callout>}}{2}\&times;\frac{N}{2}}& {\mathrm{<figure-callout\; id="2"\; label="I\; N"\; filenames="A200810093195E00452.png,A200810093195E00481.png"\; state="\{\{state\}\}">I</figure-callout>}}_{\frac{N}{}}\end{array}\right]$ Form 24

在第2个窗矩阵W₂，即i＝2，中，每个单位矩阵

的第1行系位于窗矩阵W₂的第

行，即 $((2-1)\&times;\frac{N}{2}+1)$ 行，其它元素为0。The size of W ₂ is N×N and also includes 2 identity matrices

In the second window matrix W ₂ , ie i=2, each identity matrix

The first row is located in the first row of the window matrix W ₂

OK, that is $((2-1)\&times;\frac{\mathrm{<figure-callout\; id="2"\; label="N"\; filenames="A200810093195E00452.png,A200810093195E00481.png"\; state="\{\{state\}\}">N</figure-callout>}}{2}+1)$ line, other elements are 0.

所受的通道响应的示意图。图5D中，复制部分数据

中的两个拷贝所受的平均通道响应均等于H₂。Similarly, Figure 5D shows the replicated partial data

Schematic representation of the subjected channel response. Figure 5D, copy part of the data

Both copies in were subjected to an average channel response equal to H ₂ .

From formulas 19, 20, 22 and 24, it can be deduced that in formulas 21 and 23,

${\mathrm{<figure-callout\; id="1"\; label="W"\; filenames="A200810093195E00441.png,A200810093195E00442.png"\; state="\{\{state\}\}">W</figure-callout>}}_1\&times;{\mathrm{<figure-callout\; id="1"\; label="m"\; filenames="A200810093195E00441.png,A200810093195E00442.png"\; state="\{\{state\}\}">m</figure-callout>}}_1\&times;A\&times;\stackrel{\&Right\; Arrow;}{x}={\mathrm{<figure-callout\; id="2"\; label="W"\; filenames="A200810093195E00452.png,A200810093195E00481.png"\; state="\{\{state\}\}">W</figure-callout>}}_2\&times;{\mathrm{<figure-callout\; id="2"\; label="m"\; filenames="A200810093195E00452.png,A200810093195E00481.png"\; state="\{\{state\}\}">m</figure-callout>}}_2\&times;A\&times;\stackrel{\&Right\; Arrow;}{x}$ Form 25

Therefore, if we subtract Equation 21 from Equation 23, we get

${\stackrel{\&Right\; Arrow;}{\mathrm{the\; y}}}_2-{\stackrel{\&Right\; Arrow;}{\mathrm{the\; y}}}_1=(h_2-h_1)\&times;\stackrel{\&Right\; Arrow;}{x}+{\mathrm{<figure-callout\; id="2"\; label="W"\; filenames="A200810093195E00452.png,A200810093195E00481.png"\; state="\{\{state\}\}">W</figure-callout>}}_2\&times;\stackrel{\&Right\; Arrow;}{\mathrm{no}}-{\mathrm{<figure-callout\; id="1"\; label="W"\; filenames="A200810093195E00441.png,A200810093195E00442.png"\; state="\{\{state\}\}">W</figure-callout>}}_1\&times;\stackrel{\&Right\; Arrow;}{\mathrm{no}}$ Form 26

与复制部分数据Dcpy(2)，即

相减所得的差即等于第12式的

If the Gaussian noise is ignored, it can be seen from the 26th formula that in step 330, the intercarrier interference estimation module 220 will copy part of the data DCPy(1), namely

with copying partial data Dcpy(2), i.e.

The difference obtained by subtraction is equal to the formula 12

其中，对角矩阵C即为将P等于2、a等于1，代入第1式，得到：Therefore, in step 330, the ICI estimating module 220 then calculates the obtained difference Multiplied by the diagonal matrix C, the estimated inter-carrier interference of the 12th formula is obtained

Among them, the diagonal matrix C is that P is equal to 2 and a is equal to 1, which is substituted into the first formula to obtain:

$C(i,j)=\left\{\begin{array}{cc}\frac{P}{(P-a)\&times;N}(i-\frac{N-1}{2})& i=\mathrm{<figure-callout\; id="0"\; label="j"\; filenames="A200810093195E00471.png,A200810093195E00481.png"\; state="\{\{state\}\}">j</figure-callout>}\\ 0& \mathrm{else}\end{array}\right.$ Form 27

减去估测载波间干扰即得到未受估测载波间干扰的输出信元Dout。In step 340, the intercarrier interference removal module 230 is about to receive the symbol Dr, namely

Subtract estimated intercarrier interference That is, an output cell Dout free from the estimated ICI is obtained.

In this example, P is equal to 2 as an example to illustrate steps 320 to 340 . However, the receiver-to-carrier interference cancellation method of this embodiment can be applied to transmission symbols Dt with the same original partial data, ie, transmission symbols with repeated data. For a transmission cell Dt with P pieces of the same original partial data, the copied partial data is obtained by copying the received partial data in the received cell; and then according to the product of the subtraction difference of the copied partial data and the constant sequence, it can be estimated Inter-carrier interference is measured.

Since the preamble in the symbol usually has the characteristic of data repetition, the receiver 200 and the ICI elimination method of this embodiment can be applied to the preamble. In this way, by effectively eliminating the inter-carrier interference of the pre-data, the accuracy of pre-data channel estimation can be increased.

Another example is given to illustrate the method for eliminating interference between the receiver and the carrier in this embodiment. FIG. 6A shows another example of channel response change graph within one cell time. Please refer to FIG. 6A, when the transmission cell Dt has 3 identical original partial data, that is, when P is equal to 3, the receiver 200 of the present embodiment divides the channel response in one cell time T _s into 3 Parts, respectively corresponding to the above three same original partial data. The average channel responses H ₁ ′, H ₂ ′, and H ₃ ′ are the average channel responses of the wireless channel 300 in three partial times of the cell time T _s respectively. In addition, the received symbol obtained by the receiver 200 includes three pieces of received partial data respectively corresponding to the above-mentioned three pieces of original partial data.

分别乘以3个窗矩阵中的至少其二，得到至少两个复制部分数据。Similarly, in step 320, the intercarrier interference estimation module 220 is to receive the symbol

At least two of the three window matrices are multiplied respectively to obtain at least two replicated partial data.

与

其中，复制部分数据

包括为上述3个已接收信元的第1个已接收部分数据的3个拷贝。图6B显示复制部分数据

所受的通道响应的示意图，其平均通道响应等于H₁′。For example, the inter-carrier interference estimation module 220 obtains two duplicated partial data in step 320

and

Among them, copy some data

Contains 3 copies of the first received partial data of the above 3 received cells. Figure 6B shows copying partial data

Schematic representation of the channel response for which the mean channel response is equal to H ₁ '.

所受的通道响应的示意图。图6C中，其平均通道响应等于H₃′。Also, copy some data Contains 3 copies of the 3rd received partial data which are the above 3 received cells. Figure 6C shows copying partial data

Schematic representation of the subjected channel response. In Figure 6C, its average channel response is equal to _H3 '.

与对角矩阵C′，得到估测载波间干扰

对角矩阵C′即将P等于3、a等于1，代入第1式所得。其中，Next, in step 330, the inter-carrier interference estimation module 220 according to the copied part of the data and subtraction difference

With the diagonal matrix C′, the estimated inter-carrier interference is obtained

Diagonal matrix C', that is, P equals 3 and a equals 1, is substituted into the first formula. in,

$C\&prime;(i,j)=\left\{\begin{array}{cc}\frac{3}{2\&times;N}(i-\frac{N-1}{2})& i=\mathrm{<figure-callout\; id="0"\; label="j"\; filenames="A200810093195E00471.png,A200810093195E00481.png"\; state="\{\{state\}\}">j</figure-callout>}\\ 0& \mathrm{else}\end{array}\right.$ Form 28

In this embodiment, when the transmission symbol includes three identical original partial data, the intercarrier interference estimation module 220 obtains the estimated intercarrier interference Approximate to:

${\stackrel{\&Right\; Arrow;}{e}}_{\mathrm{ici}}\&prime;\&ap;C\&prime;\&times;({\stackrel{\&Right\; Arrow;}{\mathrm{the\; y}}}_3\&prime;-{\stackrel{\&Right\; Arrow;}{\mathrm{the\; y}}}_1\&prime;)$ Form 29

Next, in step 340, the ICI removing module 230 subtracts the estimated ICI from the received symbol to obtain the output symbol Dout'.

来得到估测载波间干扰。载波间干扰估测模块220亦可以依据其它成对的复制部分资料，例如利用复制部分数据

与对应第2个已接收部分数据的复制部分数据

相减的差与常数数列，得到另一个估测载波间干扰

此时，对应的常数数列系为对角矩阵C＂的对角数列。其中，对角矩阵为将P等于1、a等于2代入第1式而得。载波间干扰估测模块220即可依据此两个估测载波间干扰

估测出另一个较佳的估测载波间干扰。接着，载波间干扰去除模块230再将已接收信元减去此最后得到的估测载波间干扰，得到输出信元。In this embodiment, the inter-carrier interference estimation module 220 is not limited to refer to the above two replicated partial data and

to get the estimated inter-carrier interference. The ICI estimating module 220 can also be based on other pairs of replicated partial data, such as using replicated partial data

Copy partial data corresponding to the second received partial data

Subtract the difference with the constant array to get another estimated ICI

At this time, the corresponding constant sequence is the diagonal sequence of the diagonal matrix C". Wherein, the diagonal matrix is obtained by substituting P equal to 1 and a equal to 2 into the first formula. The inter-carrier interference estimation module 220 can be based on The two estimated intercarrier interference

Another better estimated ICI is estimated. Next, the ICI removal module 230 subtracts the finally obtained estimated ICI from the received symbol to obtain an output symbol.

In this embodiment, when N is not a multiple of P, the method for eliminating ICI in this embodiment further includes step 320a (not shown) before step 320 . In step 320a, the ICI estimating module 230 performs an interpolation operation on the N received time-domain sampled data in the received symbol to obtain R interpolated time-domain sampled data. Among them, N+R is a multiple of P. The ICI estimating module 220 equally divides the N+R time domain sampled data into P received partial data Dprt.

In this embodiment, when the transmitter 100 modulates a frequency data Df to N subcarriers, to obtain transmission data Dt. The transmission data Dt includes N original time domain samples modulated to N subcarriers. Wherein, when there is a frequency offset between the frequencies of the N subcarriers and a reference frequency, such as frequency 0, the phases of the N original time-domain sampling data will have a corresponding phase offset.

In this case, before step 320, the method for eliminating inter-carrier interference in this embodiment further includes step 320b (not shown). In step 320b, the ICI estimating module 220 performs a frequency shift on the N received time-domain sampled data to compensate for the phase offset. Afterwards, in step 320, the ICI estimating module copies at least two received partial data of the above-mentioned compensated received symbol.

个频率取样数据Dm。The following describes the operation of the transmitter 100 when the same original partial data is to be generated. FIG. 7 shows a block diagram of the transmitter 100 of the first embodiment. Please refer to FIG. 7 , the transmitter 100 includes a modulator 110 , a subcarrier adjustment module 120 and an inverse fast Fouriertransformer (IFFT) 130 . A modulator 110 modulates a frequency data Df into a preset frequency band to obtain

frequency sampling data Dm.

个频率取样数据Dm间隔P点摆放至上述预设频段内的N个子载波，并摆放空数据至未摆放任何频率取样数据的子载波，得到一组经调整频率数据Da。Next, the subcarrier adjustment module 120 will

The frequency sampling data Dm are placed on the N subcarriers in the preset frequency band at intervals of P points, and empty data is placed on the subcarriers without any frequency sampling data to obtain a set of adjusted frequency data Da.

Next, the IFFT 130 performs an inverse fast Fourier transform on the adjusted frequency data Da to obtain a transmission symbol Dt. In this way, the transmission cell Dt includes P pieces of the same original partial data Dprt.

的一例。如图8所示，频率取样数据x₁至

被间隔摆放，且两两频率数据间插入一空数据(Null)。如此，IFFT 130进行反快速傅立叶转换后，即得到具有2个相同的原始部分数据的传输信元Dt。Figure 8 shows that when P is equal to 2, the adjusted frequency data x ₁ to

An example of As shown in Figure 8, frequency sampling data x ₁ to

They are arranged at intervals, and a null data (Null) is inserted between two pairs of frequency data. In this way, after the inverse fast Fourier transform is performed by the IFFT 130, two transmission cells Dt with the same original partial data are obtained.

Figure 8 Chang takes P equal to 2 as an example. However, P may actually be a positive integer greater than 1. In this way, the transmitter 100 can generate P transmission symbols with the same original partial data by adjusting the frequency interval between the original subcarriers to P times. Afterwards, when the receiver 200 receives the corresponding received symbol Dr through the wireless channel 300, the received symbol Dr is processed by the ICI elimination method of this embodiment.

In the inter-carrier interference elimination method in the first embodiment, as long as the transmission symbol has repeated data, the inter-carrier interference elimination method in the embodiment of the present invention is applied, and only simple subtraction and multiplication of the sequence can be performed to eliminate Intercarrier interference experienced by received cells.

second embodiment

In the second embodiment, the transmission symbol Dt includes a cyclic prefix (CP) and a data symbol (Data symbol). The operation of the receiver 200 and the transmitter 100 using the cyclic prefix data repetition characteristic of the transmission cell Dt is described here. FIG. 9 shows a flow chart of a method for eliminating ICI in the second embodiment.

Please refer to FIG. 9 , firstly, in step 910, the data synchronization module 210 receives the transmission symbol Dt generated by the transmitter 100 through the wireless channel 300 within a cell time to obtain the received symbol Dr. Wherein, the transmission cell Dt includes an original data cell Dn and a cyclic prefix CP. This cyclic prefix data CP is the same as the rear data Db of the original data cell Dn. That is to say, the post-segment data and the cyclic front-end data can be regarded as two identical original partial data Dprt in FIG. 2 .

The received cell Dr includes a corresponding received data cell and a received cyclic prefix data CP', corresponding to the data cell Dn and the cyclic prefix data CP respectively. A received post data Dn' of the received data cell corresponds to the above post data Dn.

Next, in step 920, the inter-carrier interference estimation module 220 subtracts the received cyclic prefix data CP' from the repeated part of the received back-end data Dn', and multiplies it by a predetermined constant sequence C' to determine Estimate inter-carrier interference Dici.

After that, in step 930, the ICI removal module 230 subtracts the estimated ICI from the received symbol to obtain an output symbol.

Because the front part of the received cyclic prefix data CP' in the transmission cell may be affected by the multipath transmission delay of the previous cell. Therefore, in the second embodiment, the ICI estimating module 220 estimates the ICI using the part of the received cyclic prefix data not affected by the last symbol and the received post data corresponding to it.

In this embodiment, the received data symbol Dn' includes N time-domain sampling data, and the received cyclic prefix data CP' includes G time-domain sampling data. It is assumed that the length of the wireless channel is L sampling units, and N ≥G>L. Therefore, in the received cyclic prefix data CP', the first L time-domain samples will be interfered by the last symbol, and the last G-L time-domain samples will not be interfered by the last symbol.

Before step 910, the method for estimating inter-carrier interference in this embodiment further includes step 915 (not shown). In step 915, the intercarrier interference estimation module 220 takes out the last GL time domain samples of the received cyclic prefix data CP' to obtain a part of the received cyclic prefix data CP". The intercarrier interference estimation module 220 and Take out the last GL time-domain sampling data of the received data cell Dn' to obtain a part of the received back-end data Db". Mathematically, CP” and Db” can be obtained by multiplying the received cyclic pre-data CP’ and the received post-data Db’ by a window matrix W _p respectively, where,

W _p ＝[O _(GL)×L I _(GL)×(GL) ] Formula 30

其中，Afterwards, in step 920, the inter-carrier interference estimation module 220 obtains the estimated inter-carrier interference according to the product of the difference between the subtraction of part of the received cyclic prefix data CP" and part of the received back-end data Db" and the constant sequence

in,

${\stackrel{\&Right\; Arrow;}{e}}_{\mathrm{ici}}^{\mathrm{cp}}\&ap;\frac{(N-1)}{N}\&times;m\&times;\left[\begin{array}{c}{0}_{(N-G+L)\&times;1}\\ \stackrel{\&Right\; Arrow;}{\mathrm{the\; y}}(N-1-G+L:N-1)-{\stackrel{\&Right\; Arrow;}{\mathrm{the\; y}}}_p(L:G-1)\end{array}\right]$ Form 31

为部分已接收循环前置数据CP”，即CP’的第L个至第G-1个时域取样资料所形成的向量。

为已接收数据信元。 $\stackrel{\&RightArrow;}{y}(N-1-G+L:N-1)$ 为部分已接收后段数据Db”时域取样所形成的向量。In formula 29,

It is a vector formed by part of the received cyclic prefix data CP", that is, the Lth to G-1th time-domain sampling data of CP'.

is the received data cell. $\stackrel{\&Right\; Arrow;}{\mathrm{the\; y}}(N-1-G+L:N-1)$ A vector formed by time-domain sampling of part of the received back-end data Db".

FIG. 10 shows an example of the change diagram of the wireless channel response within one cell time in the second embodiment. Referring to FIG. 10 , the estimated ICI in Equation 29 is derived. In Fig. 10, H _p1 is the average inter-carrier interference received by part of the cyclic preamble data CP"; H _p2 is the average inter-carrier interference received by the received part of the back-end data Db".

From formula 10, we can see that

${\stackrel{\&Right\; Arrow;}{e}}_{\mathrm{ici}}\&ap;m\&times;A\&times;\stackrel{\&Right\; Arrow;}{x}={\mathrm{<figure-callout\; id="1"\; label="m\; p"\; filenames="A200810093195E00441.png,A200810093195E00442.png"\; state="\{\{state\}\}">m</figure-callout>}}_p\&times;A\&times;\stackrel{\&Right\; Arrow;}{x}+{\mathrm{<figure-callout\; id="2"\; label="m\; p"\; filenames="A200810093195E00452.png,A200810093195E00481.png"\; state="\{\{state\}\}">m</figure-callout>}}_p\&times;A\&times;\stackrel{\&Right\; Arrow;}{x}$ Form 32

${\mathrm{<figure-callout\; id="1"\; label="m\; p"\; filenames="A200810093195E00441.png,A200810093195E00442.png"\; state="\{\{state\}\}">m</figure-callout>}}_p=\left\{\begin{array}{cc}m(i,j)& i=j,0\&le;i,j\&le;N-G+L-1\\ 0& \mathrm{else}\end{array}\right.$ Form 33

${\mathrm{<figure-callout\; id="2"\; label="m\; p"\; filenames="A200810093195E00452.png,A200810093195E00481.png"\; state="\{\{state\}\}">m</figure-callout>}}_p=\left\{\begin{array}{cc}m(i,j)& i=j,N-G+L-1\&le;i,j\&le;N-1\\ 0& \mathrm{else}\end{array}\right.$ Form 34

${\stackrel{\&Right\; Arrow;}{e}}_{\mathrm{ici}}^{\mathrm{cp}}=m_{\mathrm{<figure-callout\; id="2"\; label="p"\; filenames="A200810093195E00452.png,A200810093195E00481.png"\; state="\{\{state\}\}">p</figure-callout>}2}\&times;A\&times;\stackrel{\&Right\; Arrow;}{x}$ Form 35

可以分为两个部分。其中，是对应部分已接收循环前置数据CP”与部分已接收后段数据Db”的载波间干扰，即本实施例的载波间干扰消除方法所欲消除的部分。

则是对应已接收信元Dr中的其残余的载波间干扰。In Equation 30, inter-carrier interference

Can be divided into two parts. in, is the inter-carrier interference corresponding to part of the received cyclic prefix data CP" and part of the received back-end data Db", which is the part to be eliminated by the method for eliminating inter-carrier interference in this embodiment.

is the residual ICI in the received symbol Dr.

与部分已接收数据信元 $\stackrel{\&RightArrow;}{y}(N-1-G+L:N-1)$ 可以近似为Similar to formula 15 and formula 16, part of the received cyclic preamble data

with part of the received data cell $\stackrel{\&Right\; Arrow;}{\mathrm{the\; y}}(N-1-G+L:N-1)$ can be approximated as

${\stackrel{<span\; class="notranslate">\; \&Right\; Arrow;</span>}{\mathrm{<span\; class="notranslate">\; the\; y</span>}}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; L</span>}<span\; class="notranslate">\; :</span>\mathrm{<span\; class="notranslate">\; G</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&ap;</span>{\mathrm{<span\; class="notranslate">\; W</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}{\stackrel{<span\; class="notranslate">\; \&Right\; Arrow;</span>}{\mathrm{<span\; class="notranslate">\; x</span>}}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; W</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; A</span>}<span\; class="notranslate">\; \&times;</span>{\stackrel{<span\; class="notranslate">\; \&Right\; Arrow;</span>}{\mathrm{<span\; class="notranslate">\; x</span>}}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; W</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; \&times;</span>{\stackrel{<span\; class="notranslate">\; \&Right\; Arrow;</span>}{\mathrm{<span\; class="notranslate">\; no</span>}}}_{\mathrm{<span\; class="notranslate">\; p</span>}}$

Formula 36

${\stackrel{<span\; class="notranslate">\; \&Right\; Arrow;</span>}{\mathrm{<span\; class="notranslate">\; the\; y</span>}}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; G</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; L</span>}<span\; class="notranslate">\; :</span>\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&ap;</span>{\mathrm{<span\; class="notranslate">\; W</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}{\stackrel{<span\; class="notranslate">\; \&Right\; Arrow;</span>}{\mathrm{<span\; class="notranslate">\; x</span>}}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; W</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; A</span>}<span\; class="notranslate">\; \&times;</span>{\stackrel{<span\; class="notranslate">\; \&Right\; Arrow;</span>}{\mathrm{<span\; class="notranslate">\; x</span>}}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; W</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; \&times;</span>\stackrel{<span\; class="notranslate">\; \&Right\; Arrow;</span>}{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; G</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; L</span>}<span\; class="notranslate">\; :</span>\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

Formula 37

为传输信元中的后段数据，亦等于循环前置资料。M_p为类似第17、18式所表示的以 $\stackrel{\&RightArrow;}{y}(N-1-G+L:N-1)$ 的中点当原点作线性近似，展开所得对角矩阵的最后G-L个列。

为已接收循环前置数据所受的高斯噪声，

为数据信元所受的高斯噪声。in,

In order to transmit the latter data in the cell, it is also equal to the cyclic preamble data. M _p is similar to the formulas 17 and 18 expressed by $\stackrel{\&Right\; Arrow;}{\mathrm{the\; y}}(N-1-G+L:N-1)$ The midpoint of is used as the origin for a linear approximation, and the last GL columns of the resulting diagonal matrix are expanded.

is the Gaussian noise suffered by the received cyclic preamble data,

is the Gaussian noise experienced by the data cell.

In this way, in step 122, the inter-carrier interference estimation module 220 subtracts part of the received back-end data from part of the received cyclic prefix data to obtain:

$\stackrel{<span\; class="notranslate">\; \&Right\; Arrow;</span>}{\mathrm{<span\; class="notranslate">\; the\; y</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; G</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; L</span>}<span\; class="notranslate">\; :</span>\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span>{\stackrel{<span\; class="notranslate">\; \&Right\; Arrow;</span>}{\mathrm{<span\; class="notranslate">\; the\; y</span>}}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; L</span>}<span\; class="notranslate">\; :</span>\mathrm{<span\; class="notranslate">\; G</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

$=W_p\&times;(h_{p2}-h_{p1}){\stackrel{\&Right\; Arrow;}{x}}_p+W_p\&times;{\stackrel{\&Right\; Arrow;}{\mathrm{no}}}_p+W_p\&times;\stackrel{\&Right\; Arrow;}{\mathrm{no}}(N-1-G+L:N-1)$ Form 38

In this way, similar to Equation 12, in step 920, the inter-carrier interference estimation module 220 subtracts the difference between part of the received post data and part of the received cyclic prefix data

$\stackrel{\&Right\; Arrow;}{\mathrm{the\; y}}(N-1-G+L:N-1)-{\stackrel{\&Right\; Arrow;}{\mathrm{the\; y}}}_p(L:G-1)$ Multiply by a preset constant sequence to obtain the estimated inter-carrier interference

Therefore, by using the method for eliminating ICI in this embodiment, the ICI with the repeated part of the cyclic prefix data can be estimated. Therefore, changing the length of the cyclic prefix in the symbol can determine how much ICI should be removed.

In addition, since the center point of the cell time T _s is closer to the average value of the channel, the inter-carrier interference in the time domain is smaller, and the inter-carrier interference in the time domain is larger as it goes to both ends of the cell. Therefore, when the cyclic prefix data CP is used for inter-carrier interference cancellation, the cell time at the receiving end can be advanced point, let the repeated part of the cyclic prefix data CP and the general data cell be located at both ends of the cell, and a better effect of eliminating inter-carrier interference can be obtained.

Since inter-carrier interference is related to the traveling speed of the receiver 200 and the channel state of the wireless channel 300 . When the traveling speed of the receiver 200 increases, the inter-carrier interference will also increase. Therefore, the transmitter 100 of this embodiment can design the length of the cyclic prefix data according to the traveling speed, the channel state and the Gaussian noise intensity of the receiver, so as to properly remove the ICI.

The transmitter in the wireless transmission system of the embodiment of the present invention can apply a method for configuring the length of the cyclic prefix data, and configure the length of the cyclic prefix data to be greater than or equal to half the length of the original data cell. By configuring the cyclic prefix data whose length is greater than or equal to one-half of the length of the original data cell at the transmitting end, the receiving end can effectively remove most of the inter-carrier interference. The length of the cyclic prefix data is, for example, one half, three quarters or one time of the original data cell length. For example, when the FFT length is 8192 points, the length of the cyclic prefix data can be 4096 points, 6144 points or 8192 points; when the FFT length is 4096 points, the length of the cyclic prefix data can be 2048 points, 3072 points or 4096 points points; when the FFT length is 2048 points, the length of the cyclic leading data can be 1024 points, 1536 points or 2048 points; when the FFT length is 1024 points, the length of the cyclic leading data can be 512 points, 768 points or 1024 points points; when the FFT length is 512 points, the length of the cyclic leading data can be 256 points, 384 points or 512 points; when the FFT length is 256 points, the length of the cyclic leading data can be 128 points, 192 points or 256 points points; when the FFT length is 128 points, the length of the cyclic leading data can be 64 points, 96 points or 128 points; when the FFT length is 64 points, the length of the cyclic leading data can be 32 points, 48 points or 64 points point.

The operation of the transmitter 100 for generating transmission cells in this embodiment will be described. FIG. 11 shows a block diagram of the transmitter 100 of the second embodiment. In this embodiment, the transmitter 100 includes a modulator 110', an IFFT 120' and a cyclic prefix generator 130'. Please refer to FIG. 11 , the modulator 110' modulates the frequency data Df' to obtain a modulated frequency cell Dm'. IFFT 120' performs inverse fast Fourier transform on the modulated frequency cell Dm' to obtain the data cell Dn.

The cyclic prefix generator 130' receives the data cell Dn, and generates appropriate cyclic prefix data according to the traveling speed of the receiver 200, the state of the wireless channel 300, and the Gaussian noise intensity of the receiver. The transmission cell Dt includes the cyclic prefix data CP and the data cell Dn.

Wherein, the cyclic prefix generator 130' determines the length of the cyclic prefix data CP according to at least one of the traveling speed of the receiver 200, the noise intensity of the wireless channel 300, and the channel state information. In FIG. 11 , the cyclic prefix generator 130' determines the length of the cyclic prefix data CP according to the traveling speed Sp of the receiver 200. In this embodiment, when the traveling speed Sp of the receiver 200 is higher than a threshold, the cyclic prefix generator 130' generates cyclic prefix data with a first length. When the traveling speed Sp of the receiver 200 is not higher than the threshold, the cyclic prefix generator 130' generates cyclic prefix data with a second length. Wherein, the first length is longer than the second length.

From the above, it can be seen that when the receiver travels at a faster speed and the ICI suffered by the transmitted symbols is severe, the transmitter will generate a longer cyclic prefix data CP. In this way, the receiver can remove more ICI. The transmitter generates shorter cyclic prefix data when the receiver is traveling at a slower speed so that the transmitted cells experience less ICI. In this way, the transmission efficiency of transmitting cells can be increased. Therefore, by applying the method for eliminating inter-carrier interference in this embodiment, a trade-off can be made between inter-carrier interference and transmission efficiency.

In the first and second embodiments, the wireless receiving system 10 can also be designed as a multi-input multi-output (MIMO) system. In this system, the transmitter 100 has multiple transmit antennas, and the receiver 200 also has multiple receive antennas. In this environment, the ICI cancellation methods introduced in the first and second embodiments can also be used to perform ICI cancellation on each receiving antenna.

The effects of the ICI elimination methods of the first and second embodiments are described here. FIG. 12 shows the residual ICI energy received by applying the ICI cancellation method of the first embodiment, applying the traditional ICI self-cancellation method and completely not using the ICI cancellation method under different mobile environments.

The vertical axis of FIG. 12 represents the magnitude of the residual inter-carrier interference energy P _ICI suffered by the transmitted symbol. The horizontal axis of FIG. 12 represents the size of the received Doppler spread fdTs of the receiver. The magnitude of the Doppler spread fdTs corresponds to the traveling speed of the receiver. For example, under the conditions of the carrier frequency of 2.5GHz, the bandwidth of 11.2MHz, and the FFT size of 1024, the traveling speed of the receiver corresponding to fdTs equal to 0.05 is about 235 km/h; the receiver corresponding to fdTs equal to 0.1 The traveling speed of the vehicle is about 470 km/h.

In FIG. 12 , the curve 121 represents the relationship between the ICI received by the received symbol and the Doppler spread when no ICI removal method is used. Curve 122 represents the relationship between the residual ICI and the Doppler spread when using the ICI self-removal method. Curve 123 represents a relationship curve between residual ICI and Doppler spread when the method for removing ICI of this embodiment is used.

It can be known from the curves 121 to 123 that the greater the Doppler spread, the greater the energy of the inter-carrier interference. In FIG. 12 , when fdTs is equal to 0.05, the intercarrier interference self-cancellation method can reduce the intercarrier interference from -24dB in curve 121 to -41dB in curve 122 . Therefore, using the inter-carrier interference self-cancellation method can reduce the inter-carrier interference by about 17dB.

When fdTs is equal to 0.05, using the inter-carrier interference elimination method of this embodiment can reduce the inter-carrier interference from -24dB in curve 121 to -57dB in curve 123 . Therefore, using the method for eliminating inter-carrier interference of this embodiment can reduce about 33 dB of inter-carrier interference. Therefore, it can be seen from FIG. 12 that when the transmission symbol has repeated data, using the ICI elimination method of this embodiment can significantly reduce the ICI, and has a better effect than the traditional ICI self-cancellation method.

FIG. 13 and FIG. 14 respectively show the magnitudes of the real part and the imaginary part of the ICI actually experienced by the received symbol when the transmitted symbol has repeated data, and the result of estimating the ICI.

The horizontal axes in FIG. 13 and FIG. 14 represent the sampling time points, and the vertical axes represent the magnitudes of the real part and the imaginary part of the inter-carrier interference, respectively. Wherein, the curve 131 of Fig. 13 and the curve 141 of Fig. 14 represent respectively the real part and the imaginary part of the intercarrier interference actually suffered by the received cells, and the curve 132 of Fig. 13 and the curve 142 of Fig. 14 respectively represent the intercarrier interference elimination The real and imaginary parts of the estimated intercarrier interference estimated by the method.

It can be observed from the figure that the curves 131 and 132 almost overlap, and the curves 141 and 142 almost overlap. Therefore, it can be seen from FIG. 13 and FIG. 14 that when the transmission symbol has repeated data, the method for eliminating ICI in this embodiment can accurately estimate the ICI.

Figure 15 shows the channel estimation mean square error (MSE) of the transmitted 802.16e preamble data under different Doppler spreads and different Gaussian noise intensities. The vertical axis of FIG. 15 is the average squared error, and the horizontal axis is the signal-to-noise ratio (SNR). Curves 151 to 154 are relationship curves of SNR and channel estimation mean squared error corresponding to the Doppler spread fdTs of 0, 0.05, 0.1 and 0.2 without using the ICI cancellation method. Curves 155 to 158 are relationship curves of SNR and channel estimation mean squared error corresponding to the Doppler spread fdTs of 0, 0.05, 0.1 and 0.2 when using the ICI cancellation method of this embodiment.

The mean squared error of channel estimation is affected by intercarrier interference and Gaussian noise strength, respectively. Looking at the curve 153, when fdTs is equal to 0.1, the average squared error of channel estimation is about -30dB without using any ICI cancellation method. At this time, increasing the signal-to-noise ratio can't make the average squared error drop even lower. Compared with observing the curve 157 at the same traveling speed, in the case of using the ICI cancellation method of this embodiment, the average squared error of the channel estimation can be less than -50dB. Therefore, the accuracy of channel estimation can be greatly improved by using the ICI elimination method of this embodiment.

FIG. 16 shows an example of the relationship between the received ICI and the Doppler spread in the case of different lengths of the cyclic prefix data by using the repetition characteristic of the cyclic prefix data. Curve 161 is a relationship curve between Doppler spread and ICI when no ICI removal method is used. Curves 162 to 165 are the Doppler spread and carrier wave obtained by using the inter-carrier interference removal method when the length of the cyclic prefix data is 1/8, 1/4, 1/2 and 3/4 of the original data symbol. Interference curves.

For example, it can be seen from the curve 161 that when the Doppler spread fdTs is equal to 0.05, the ICI received by the received symbol is about -24dB. It can be seen from the curve 162 that when the length of the cyclic prefix data is 1/8, the obtained inter-carrier interference is about -26dB. At this time, the method for eliminating inter-carrier interference in this embodiment can eliminate 2 dB of inter-carrier interference.

It can be seen from the curve 165 that when the length of the cyclic prefix data is 3/4, the obtained ICI is about -40dB by using the ICI elimination method of this embodiment. At this time, the method for eliminating inter-carrier interference in this embodiment can eliminate 16 dB of inter-carrier interference. It can be seen from FIG. 16 that when the length of the cyclic prefix data is longer, more inter-carrier interference can be eliminated.

In the above two embodiments, the application of the OFDM communication technology is taken as an example. In practical applications, the method for eliminating inter-carrier interference in the embodiment of the present invention can be applied to transmission symbols with repetitive data characteristics, so as to eliminate the inter-carrier interference of received symbols.

In the ICI elimination method of the embodiment of the present invention, only the multiplication and subtraction operations of the sequence are performed to obtain the estimated ICI. Therefore, as long as the transmission symbol has repeated data, the method for eliminating ICI in the embodiment of the present invention can be applied to eliminate the ICI suffered by the received symbol.

Compared with the traditional "multi-level ICI reduction method" which requires very complex calculations for channel state estimation and ICI elimination, the ICI elimination method in the embodiment of the present invention has the effect of being easier to implement. In addition, the ICI elimination method in the embodiment of the present invention has a better effect than the traditional ICI self-elimination method. Therefore, using the method for eliminating inter-carrier interference in the embodiment of the present invention can achieve a very excellent effect of eliminating inter-carrier interference under the premise of low computational complexity.

In summary, although the present invention has been disclosed as above with a preferred embodiment, it is not intended to limit the present invention. Those skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be subject to the content defined by the patent scope of the application.

Claims (80)

1. An intercarrier interference cancellation method for canceling intercarrier interference of a received cell, the method comprising:

receiving a transmission cell generated by a transmitter through a wireless channel within a cell time to obtain the received cell, wherein the transmission cell comprises P original part data, each original part data comprises a plurality of original time domain sampling data, each original part data is the same, and the received cell comprises P received part data which respectively correspond to the original part data;

copying at least two of the P received partial data in a time domain to obtain at least two copied partial data, wherein each copied partial data comprises P copies of the corresponding received partial data, and P is a positive integer greater than 1;

determining an estimated intercarrier interference according to a product of a difference of the subtraction of the at least two duplicated data and a constant sequence; and

subtracting the estimated intercarrier interference from the received cell to obtain an output cell.

2. The method of claim 1 wherein the received cell includes N received time-domain samples, N being a positive integer, and the step of replicating multiplies the received cell by at least two of P window matrices to generate the at least two replica portions, wherein an ith window matrix has a size of N x N and includes P identity matrices, and the size of each identity matrix is N x N

Every 1 st row of the unit matrix is located at the ith window matrixAnd the other elements of the ith window matrix are 0, wherein i is a positive integer less than or equal to P.

3. The method of claim 2, wherein the constant number is a diagonal number of rows of a diagonal matrix C, and the element in the ith row and the jth column of the diagonal matrix C is

<math> <mrow> <mi>C</mi> <mrow> <mo>(</mo> <mi>i</mi> <mo>,</mo> <mi>j</mi> <mo>)</mo> </mrow> <mo>=</mo> <mrow> <mfenced open='{' close=''> <mtable> <mtr> <mtd> <mfrac> <mi>P</mi> <mrow> <mrow> <mo>(</mo> <mi>P</mi> <mo>-</mo> <mi>a</mi> <mo>)</mo> </mrow> <mo>&times;</mo> <mi>N</mi> </mrow> </mfrac> <mrow> <mo>(</mo> <mi>i</mi> <mo>-</mo> <mfrac> <mrow> <mi>N</mi> <mo>-</mo> <mn>1</mn> </mrow> <mn>2</mn> </mfrac> <mo>)</mo> </mrow> </mtd> <mtd> <mi>i</mi> <mo>=</mo> <mi>j</mi> </mtd> </mtr> <mtr> <mtd> <mn>0</mn> </mtd> <mtd> <mi>else</mi> </mtd> </mtr> </mtable> </mfenced> <mo>,</mo> </mrow> </mrow></math> Wherein i and j are positive integers less than or equal to P, and a is a positive integer less than P.

4. The method of claim 1, wherein the received cell is preamble data.

5. The method of claim 1, wherein the transmitted cell includes N original time domain samples, the received cell correspondingly includes N received time domain samples, N is a non-P multiple, and before the copying step, the method comprises:

and performing interpolation operation on the N received time domain sampling data to obtain R interpolated time domain sampling data, wherein N + R is a multiple of P, and the N + R time domain sampling data are divided into the P received partial data.

6. The method of claim 1, wherein the transmitted cell includes N original time domain samples modulated to N subcarriers, the received cell correspondingly includes N received time domain samples, the N subcarriers have a frequency offset from a reference frequency such that the N original time domain samples have a corresponding phase offset relative to a phase of the N original time domain samples, and the step of replicating comprises:

the N received time domain sample data are frequency shifted to compensate for the phase offset.

7. The method of claim 1, wherein the transmitted cell is output by one of a plurality of antennas of a transmitter of an MIMO system, and the received cell is received by one of a plurality of antennas of a receiver of the MIMO system.

8. The method of claim 1, wherein the method is applied to OFDM technology, and the transmission cell is a cell.

9. A receiver for receiving a transmission cell generated by a transmitter over a wireless channel during a cell time to obtain a received cell and eliminating inter-carrier interference of the received cell, the transmission cell including P original portions of data, each original portion of data including a plurality of original time domain samples, each original portion of data being identical, the received cell including a plurality of received portions of data corresponding to the original portions of data, the receiver comprising:

a data synchronization module for synchronizing the received cells;

an intercarrier interference estimation module, for duplicating at least two of the P received partial data in time domain to obtain at least two duplicated partial data, each duplicated partial data includes P copies of the received partial data corresponding to each duplicated partial data, P is a positive integer greater than 1; and determining an estimated intercarrier interference according to a product of a difference of the subtraction of the at least two duplicated data and a constant sequence;

an inter-carrier interference removing module for subtracting the estimated inter-carrier interference from the received cell to obtain an output cell;

a fast Fourier transformer for transforming the output cell into a frequency domain; and

a demodulator for demodulating the output cells in the frequency domain.

10. The receiver of claim 9 wherein the received cell includes N received time domain samples divided into the P received portions, N being a positive integer, the ici estimation module multiplying the received cell by at least two of P window matrices to generate the at least two copies of the partial data, wherein an ith window matrix is N x N in size and includes P identity matrices, each identity matrix being of size

And the other elements are 0, wherein i is a positive integer less than or equal to P.

11. The receiver of claim 10 wherein the constant sequence is a diagonal bit sequence of a diagonal matrix C in which the ith row and jth column elements are <math> <mrow> <mi>C</mi> <mrow> <mo>(</mo> <mi>i</mi> <mo>,</mo> <mi>j</mi> <mo>)</mo> </mrow> <mo>=</mo> <mrow> <mfenced open='{' close=''> <mtable> <mtr> <mtd> <mfrac> <mrow> <mi>P</mi> <mo>&times;</mo> <mrow> <mo>(</mo> <mi>N</mi> <mo>-</mo> <mn>1</mn> <mo>)</mo> </mrow> </mrow> <mrow> <mrow> <mo>(</mo> <mi>P</mi> <mo>-</mo> <mi>a</mi> <mo>)</mo> </mrow> <mo>&times;</mo> <mi>N</mi> </mrow> </mfrac> <mrow> <mo>(</mo> <mi>i</mi> <mo>-</mo> <mfrac> <mrow> <mi>N</mi> <mo>-</mo> <mn>1</mn> </mrow> <mn>2</mn> </mfrac> <mo>)</mo> </mrow> <mo>/</mo> <mrow> <mo>(</mo> <mi>N</mi> <mo>-</mo> <mn>1</mn> <mo>)</mo> </mrow> </mtd> <mtd> <mi>i</mi> <mo>=</mo> <mi>j</mi> </mtd> </mtr> <mtr> <mtd> <mn>0</mn> </mtd> <mtd> <mi>else</mi> </mtd> </mtr> </mtable> </mfenced> <mo>,</mo> </mrow> </mrow></math> Wherein i and j are positive integers less than or equal to P, and a is a positive integer less than P.

12. The receiver of claim 9 wherein the received cell is preamble data.

13. The receiver of claim 9, wherein the transmission cell includes N original time-domain samples, the received cell correspondingly includes N received time-domain samples, N is a multiple other than P, and the intercarrier interference estimation module interpolates the N received time-domain samples to obtain R interpolated time-domain samples, where N + R is a multiple of P; the intercarrier interference estimation module equally divides the N + R time domain sample data into the P received partial data.

14. The receiver of claim 9 wherein the transmission cell includes N original time domain samples modulated onto N subcarriers having a frequency offset from a reference frequency such that the N original time domain samples have a corresponding phase offset in phase, the received cell correspondingly includes N received time domain samples, the intercarrier interference estimation module frequency shifts the N received time domain samples to compensate for the phase offset, the intercarrier interference estimation module then copies the at least two received portions of the compensated received cell.

15. The receiver of claim 9 wherein the transmitter and the receiver are a transmitter and a receiver of a MIMO system, one of the plurality of antennas of the transmitter outputting the transmitted cell and one of the plurality of antennas of the receiver receiving the received cell.

16. The receiver of claim 9 wherein the receiver is adapted for communication technology and the transmission cells are OFDM cells.

17. A wireless transmission system, comprising:

a transmitter for generating and transmitting a transmission cell in time domain, the transmission cell including P original partial data, each original partial data including a plurality of original time domain sample data, each original received partial data being the same; and

a receiver for receiving the transmitted cell over a wireless channel in a cell time to obtain a received cell, the received cell including P received portions of data corresponding to the P original portions of data, respectively, comprising:

a data synchronization module for synchronizing the received cells;

an intercarrier interference estimation module, for duplicating at least two of the P received partial data in time domain to obtain at least two duplicated partial data, each duplicated partial data includes P copies of the corresponding received partial data, P is a positive integer greater than 1; and determining an estimated intercarrier interference according to a product of a difference of the subtraction of the at least two duplicated data and a constant sequence;

an inter-carrier interference removing module for subtracting the estimated inter-carrier interference from the received cell to obtain an output cell;

a fast Fourier transformer for transforming the output cell into a frequency domain; and

a demodulator for demodulating the output cells in the frequency domain.

18. The wireless transmission system of claim 17 wherein the transmission cell includes N original time-domain sample data, the received cell correspondingly includes N received time-domain sample data, and N is a non-P multiple, the intercarrier interference estimation module interpolates the N received time-domain sample data to obtain R interpolated time-domain sample data, wherein N + R is a P multiple; the intercarrier interference estimation module then equally divides the N + R time-domain sample data into the P received partial data.

19. The wireless transmission system of claim 17 wherein the transmitter modulates a frequency data to N subcarriers to obtain the transmission cell, the transmission cell comprising N original time domain samples, the N subcarriers having a frequency offset from a reference frequency such that phases of the N original time domain samples have a corresponding phase offset; the received cell correspondingly includes N received time domain sample data; the intercarrier interference estimation module performs frequency shift on the N received time domain sample data to compensate for the phase offset, and then copies the at least two received portions of the compensated received cell.

20. The wireless transmission system of claim 17, wherein the transmitter comprises:

a modulator for modulating a frequency data into a predetermined frequency band to obtain

Sampling data at each frequency;

a sub-carrier adjustment module for adjusting the sub-carrierPlacing frequency sampling data intervals P to N subcarriers in the preset frequency band, and placing null data to the subcarriers without any frequency sampling data to obtain a group of adjusted frequency data; and

an inverse fast Fourier transformer for inverse fast Fourier transforming the adjusted frequency data to obtain the transmission cell.

21. The wireless receiving system of claim 17 wherein the wireless receiving system is a MIMO system, the transmitter has a plurality of transmit antennas, one of the transmit antennas transmits the transmitted cell, the receiver has a plurality of receive antennas, one of the receive antennas receives the received cell.

22. The system of claim 17 wherein the wireless receiving system is adapted for communication technology and the transmission cells are OFDM cells.

23. An intercarrier interference cancellation method for canceling intercarrier interference of a received cell, the method comprising:

receiving a transmission cell generated by a transmitter through a wireless channel within a cell time to obtain a received cell, wherein the received cell comprises an original data cell and a cyclic prefix, the cyclic prefix is the same as the back data of the original data cell, the received cell correspondingly comprises a received data cell and a received cyclic prefix, the received data cell corresponds to the original data cell and the cyclic prefix, and the received back data of the received data cell corresponds to the back data;

determining an estimated intercarrier interference based on a product of a difference between at least a portion of the received cyclic prefix data and at least a portion of the received postamble data subtracted by a constant sequence; and

subtracting the estimated intercarrier interference from the received cell to obtain an output cell.

24. The method of claim 23 wherein the channel length of the radio channel is L samples, the received cyclic prefix includes G time-domain samples, and wherein the method of intercarrier interference cancellation comprises, prior to the step of estimating:

taking out G-L time domain sampling data after the received cyclic prefix data to obtain a part of the received cyclic prefix data, and taking out G-L time domain sampling data after the received data cell to obtain a part of the received back section data;

wherein the estimating step determines the estimated intercarrier interference according to a product of a difference between the subtraction of the portion of the received cyclic prefix data and the portion of the received postamble data and a constant sequence.

25. The method for canceling intercarrier interference according to claim 24, wherein in the step of extracting the partial cyclic prefix data and the partial postamble data, the received cyclic prefix data and the received postamble data are multiplied by a window matrix W_pRespectively obtaining the partial cyclic prefix data and the partial posterior data, wherein,

W_p＝[O_(G-L)×L I_(G-L)×(G-L)]。

26. the method of claim 25 wherein the received data cells include N time-domain samples, the constant sequence is a diagonal sequence of a diagonal matrix C, and the element in the ith column and jth row of the C matrix is

$C(i,j)=\left\{\begin{array}{cc}(i-\frac{N-1}{2})/(N-1),& i=j\\ 0,& \mathrm{else}\end{array}\right..$

27. The method of claim 23, wherein the intercarrier interference cancellation is applied to communication technology, and the transmission cell is an OFDM cell.

28. The method of claim 23, wherein the length of the cyclic prefix is greater than or equal to one-half of the length of the original data cell.

29. A wireless transmission system, comprising:

a transmitter for generating and transmitting a transmission cell of the time domain, including an original data cell and a cyclic prefix, the cyclic prefix being identical to an original postamble of the original data cell; and

a receiver for receiving the transmitted cell via a wireless channel within a cell time to obtain a received cell, the received cell correspondingly including a received data cell and a received cyclic prefix corresponding to the original data cell and the cyclic prefix, respectively, and a received back data of the received data cell corresponding to the back data, the receiver comprising:

a data synchronization module for synchronizing the received cells;

an intercarrier interference estimation module for determining an estimated intercarrier interference according to a product of a difference between the subtraction of the part of the received cyclic prefix data and the part of the received postamble data and a constant sequence;

an inter-carrier interference removing module for subtracting the estimated inter-carrier interference from the received cell to obtain an output cell;

a fast Fourier transformer for transforming the output cell into a frequency domain; and

a demodulator for demodulating the output cells in the frequency domain.

30. The wireless transmission system of claim 29, wherein the transmitter comprises:

a modulator for modulating a frequency data;

an inverse fast fourier transformer for transforming the modulated frequency data into the original data cells in the time domain; and

a cyclic prefix generator for generating the cyclic prefix identical to the original postamble data and determining the length of the cyclic prefix according to at least one of the traveling speed of the receiver, the noise intensity of the wireless channel and the channel state information.

31. The wireless transmission system of claim 30 wherein the cyclic prefix generator generates cyclic prefix data having a first length if the speed of travel of the receiver is above a threshold, and a second length if the speed of travel of the receiver is not above the threshold, wherein the first length is longer than the second length.

32. The wireless transmission system of claim 29 wherein the length of the cyclic prefix is greater than or equal to one-half the length of the original data cell.

33. The system of claim 29 wherein the wireless transmission system is applied to communication technology and the transmission cells are OFDM cells.

34. An inter-carrier interference cancellation method, comprising:

receiving a transmission cell generated by a transmitter through a wireless channel within a cell time to obtain the received cell, wherein the transmission cell comprises at least two identical original part data, and the received cell comprises at least two corresponding received part data which respectively correspond to the at least two original part data;

determining an estimated intercarrier interference according to a product of a difference of the subtraction of the at least two received partial data and a constant sequence; and

subtracting the estimated intercarrier interference from the received cell to obtain an output cell.

35. The method according to claim 34, wherein the transmission cell includes P original portions of data, each of the original portions of data being the same, the received cell includes P received portions of data, each corresponding to a respective one of the original portions of data, and the method comprises, before the estimating step:

copying at least two of the P received partial data in a time domain to obtain the at least two copied partial data, wherein each copied partial data comprises P copies of the corresponding received partial data, and P is a positive integer greater than 1;

wherein, in the estimating step, the estimated intercarrier interference is determined according to the product of the difference of the subtraction of the at least two copies and the constant sequence.

36. The method of claim 35 wherein the received cell includes N received time-domain samples, N being a positive integer, and the step of replicating multiplies the received cell by at least two of P window matrices to generate the at least two replica portions, wherein an ith window matrix has a size of N x N and includes P identity matrices, and each identity matrix has a size of P identity matrices

The other element (Entry) is 0, where i is a positive integer less than or equal to P.

37. The method of claim 35, wherein the constant sequence has a size of nxn, wherein the constant sequence is a diagonal sequence of a diagonal matrix C, and the element of the ith column and the jth row in the diagonal matrix C is

<math> <mrow> <mi>C</mi> <mrow> <mo>(</mo> <mi>i</mi> <mo>,</mo> <mi>j</mi> <mo>)</mo> </mrow> <mo>=</mo> <mrow> <mfenced open='{' close=''> <mtable> <mtr> <mtd> <mfrac> <mrow> <mi>P</mi> <mo>&times;</mo> <mrow> <mo>(</mo> <mi>N</mi> <mo>-</mo> <mn>1</mn> <mo>)</mo> </mrow> </mrow> <mrow> <mrow> <mo>(</mo> <mi>P</mi> <mo>-</mo> <mi>a</mi> <mo>)</mo> </mrow> <mo>&times;</mo> <mi>N</mi> </mrow> </mfrac> <mrow> <mo>(</mo> <mi>i</mi> <mo>-</mo> <mfrac> <mrow> <mi>N</mi> <mo>-</mo> <mn>1</mn> </mrow> <mn>2</mn> </mfrac> <mo>)</mo> </mrow> <mo>/</mo> <mrow> <mo>(</mo> <mi>N</mi> <mo>-</mo> <mn>1</mn> <mo>)</mo> </mrow> </mtd> <mtd> <mi>i</mi> <mo>=</mo> <mi>j</mi> </mtd> </mtr> <mtr> <mtd> <mn>0</mn> </mtd> <mtd> <mi>else</mi> </mtd> </mtr> </mtable> </mfenced> <mo>,</mo> </mrow> </mrow></math> Wherein i and j are positive integers less than or equal to P, and a is a positive integer less than P.

38. The method of claim 35, wherein the received cell is preamble data.

39. The method of claim 34, wherein the transmission cell includes a primary data cell and a cyclic prefix, the cyclic prefix is identical to a primary postamble of the primary data cell, the two primary portions are the cyclic prefix and the primary postamble, the received cell correspondingly includes a received data cell and a received cyclic prefix, corresponding to the primary data cell and the cyclic prefix, respectively, a received postamble of the received data cell corresponds to the postamble, the received cyclic prefix and the received postamble are the two received portions;

wherein the estimating step determines the estimated intercarrier interference according to a product of a difference of at least partial subtraction of the received cyclic prefix data and the received postamble data and the constant sequence.

40. The method according to claim 39, wherein the channel length of the radio channel is L samples, the received cyclic prefix data includes G time-domain samples, and wherein the method comprises, prior to the estimating step:

taking out the last G-L time domain sampling data of the received cyclic prefix data to obtain a part of the received cyclic prefix data, and taking out the last G-L time domain sampling data of the received data cell to obtain a part of the received back section data;

wherein the estimating step determines the estimated intercarrier interference according to a product of a difference between the portion of the received cyclic prefix data and the portion of the received postamble data and a constant sequence.

41. The method of claim 40, wherein in the step of extracting the portion of cyclic prefix data and the portion of postamble data, the received cyclic prefix data and the received multiplied by a window matrix W_pRespectively obtaining the partial cyclic prefix data and the partial posterior data, wherein,

W_p＝[O_(G-L)×L I_(G-L)×(G-L)]。

42. the method of claim 41, wherein the received data cell includes N time-domain samples, the constant sequence is a diagonal sequence of a diagonal matrix C, and the element in the ith column and jth row of the diagonal matrix C is

$C(i,j)=\left\{\begin{array}{cc}(i-\frac{N-1}{2})/(N-1),& i=j\\ 0,& \mathrm{else}\end{array}\right..$

43. The method of claim 39, wherein the length of the cyclic prefix is greater than or equal to one-half of the length of the original data cell.

44. The method of claim 34, wherein the method is applied to communication technology, and the transmission cell is an OFDM cell.

45. A method for configuring cyclic prefix length is applicable to a communication system, wherein the communication system comprises at least one transmission cell, the transmission cell comprises cyclic prefix data and a data cell, and the method comprises the following steps:

the length of the cyclic prefix is configured to be greater than or equal to one-half of the length of the data cell.

46. The method of claim 45, wherein the method is applied to an inter-carrier interference cancellation method.

47. The method of claim 45, wherein the communication system is an OFDM communication system.

48. The method of claim 45, wherein the length of the cyclic prefix is one of one half, three quarters and one time the length of the data cell.

49. The method of claim 48, wherein the data cell is 8192 dots, and the length of the cyclic prefix data is configured to be one of 4096 dots, 6144 dots and 8192 dots.

50. The method of claim 48, wherein the data cell is 4096 dots, and the length of the cyclic prefix data is configured to be one of 2048 dots, 3072 dots and 4096 dots.

51. The method of claim 48, wherein the data cell is 2048 points, and the cyclic prefix length is one of 1024 points, 1536 points, and 2048 points.

52. The method of claim 48, wherein the data cell is 1024 points, and the length of the cyclic prefix is configured to be one of 512 points, 768 points and 1024 points.

53. The method of claim 48, wherein the data cell is 512 points, and the length of the cyclic prefix is configured to be one of 256 points, 384 points and 512 points.

54. The method of claim 48, wherein the data cell is 256 points, and the length of the cyclic prefix is configured to be one of 128 points, 192 points and 256 points.

55. The method of claim 48, wherein the data cell is 128-point, and the length of the cyclic prefix is configured to be one of 64-point, 96-point and 128-point.

56. The method of claim 48, wherein the data cell is 64-point, and the length of the cyclic prefix is configured to be one of 32-point, 48-point and 64-point.

57. A transmitter is suitable for a communication system and is used for generating and transmitting a transmission cell of a time domain, wherein the transmission cell comprises an original data cell and a cyclic prefix, the cyclic prefix is the same as an original back segment data of the original data cell, and the length of the cyclic prefix is more than or equal to one half of the length of the original data cell.

58. The transmitter of claim 57 wherein the transmitter is adapted for an inter-carrier interference cancellation method.

59. The transmitter of claim 57, wherein the communication system is an OFDM communication system.

60. The transmitter of claim 57 wherein the length of the cyclic prefix is one of one-half, three-quarters and one-time the length of the original data cell.

61. The transmitter of claim 60 wherein the original data cell is 8192 points, and the cyclic prefix is configured to have a length of one of 4096 points, 6144 points and 8192 points.

62. The transmitter of claim 60 wherein the original data cell is 4096 dots, and the cyclic prefix is configured to have a length of one of 2048 dots, 3072 dots and 4096 dots.

63. The transmitter of claim 60 wherein the original data cell is 2048 points, and the cyclic prefix is configured to be one of 1024 points, 1536 points, and 2048 points in length.

64. The transmitter of claim 60 wherein the original data cell is 1024 points, configuring the length of the cyclic prefix to be one of 512 points, 768 points and 1024 points.

65. The transmitter of claim 60 wherein the original data cell is 512 points, configuring the length of the cyclic prefix to be one of 256 points, 384 points and 512 points.

66. The transmitter of claim 60 wherein the original data cell is 256-point, and the cyclic prefix is configured to be one of 128-point, 192-point, and 256-point in length.

67. The transmitter of claim 60 wherein the original data cell is 128-point, and the cyclic prefix length is configured to be one of 64-point, 96-point and 128-point.

68. The transmitter of claim 60 wherein the original data cell is 64-point, and the cyclic prefix is configured to be one of 32-point, 48-point and 64-point in length.

69. A wireless transmission system, comprising:

a transmitter for generating and transmitting a transmission cell of time domain, including an original data cell and a cyclic prefix, the cyclic prefix being the same as an original postamble of the original data cell, wherein the length of the cyclic prefix is greater than or equal to one-half of the length of the original data cell; and

a receiver for receiving the transmitted cell through a wireless channel within a cell time to obtain a received cell, wherein the received cell correspondingly comprises a received data cell and a received cyclic prefix corresponding to the original data cell and the cyclic prefix, and a received back-end data of the received data cell corresponds to the original back-end data.

70. The wireless transmission system of claim 69 wherein the system is adapted for an intercarrier interference cancellation method.

71. The wireless transmission system of claim 69 wherein the system is an OFDM communication system.

72. The wireless transmission system of claim 69 wherein the length of the cyclic prefix is one of one-half, three-quarters, and one-time the length of the original data cell.

73. The wireless transmission system of claim 72, wherein the original data cell is 8192 points, and the cyclic prefix data is configured to have a length of one of 4096 points, 6144 points and 8192 points.

74. The wireless transmission system of claim 72 wherein the original data cell is 4096 dots, and the cyclic prefix is configured to have a length of one of 2048 dots, 3072 dots and 4096 dots.

75. The wireless transmission system of claim 72 wherein the original data cell is 2048 points, and the cyclic prefix is configured to have a length of one of 1024 points, 1536 points, and 2048 points.

76. The wireless transmission system of claim 72 wherein the original data cell is 1024 points, and the length of the cyclic prefix is configured to be one of 512 points, 768 points and 1024 points.

77. The wireless transmission system of claim 72 wherein the original data cell is 512 points, and the length of the cyclic prefix is configured to be one of 256 points, 384 points and 512 points.

78. The wireless transmission system of claim 72 wherein the original data cell is 256-point, and the cyclic prefix is configured to have a length of one of 128-point, 192-point and 256-point.

79. The wireless transmission system of claim 72 wherein the original data cell is 128-point, and the cyclic prefix is configured to be one of 64-point, 96-point and 128-point in length.

80. The wireless transmission system of claim 72 wherein the original data cell is 64-point, and the cyclic prefix is configured to be one of 32-point, 48-point and 64-point in length.

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