WO2011044846A1

WO2011044846A1 - Channel estimation method, apparatus and communication system

Info

Publication number: WO2011044846A1
Application number: PCT/CN2010/077751
Authority: WO
Inventors: 李睿; 哈加瓦那•维波诺; 李永会; 卢赛蒂克•布兰卡; 杨学志; 蒋伟
Original assignee: 华为技术有限公司
Priority date: 2009-10-14
Filing date: 2010-10-14
Publication date: 2011-04-21
Also published as: CN102045285A; CN102045285B

Abstract

A channel estimation method, apparatus and communication system are provided in the embodiments of the present invention. The channel estimation method includes the following steps: obtaining received signals, and the received signals include the received pilot signal and the received data signal; obtaining an initial channel estimation value based on the received pilot signal and an initial channel estimation matrix, and the initial channel estimation matrix includes the interference information among sub-carriers; iterating the channel estimation in order to obtain the follow-up channel estimation value according to the initial channel estimation value and the obtained received signals. A corresponding channel estimation apparatus is also provided in the embodiments of the present invention. A communication system including the channel estimation apparatus is also provided in the present invention. The channel estimation method, apparatus and system provided in the embodiments of the present invention consider the impacts of the interference among sub-carriers, thus improving the accuracy of channel estimation.

Description

Channel estimation method, device and communication system

The embodiments of the present invention relate to the field of mobile communications technologies, and in particular, to a channel estimation method, apparatus, and communication system. Background technique

The transmitter and receiver of the wireless communication system use multiple antennas at the same time, and the signal capacity and reliability can be greatly improved without increasing the bandwidth and the transmission power. This technique is called Multiple Input and Multiple Output (hereinafter). Abbreviation: MIMO) technology. The multi-antenna system combines Space Time Coding (STC) to generate spatial diversity, which can reduce the bit error rate and improve system reliability. The MIM0 system can also adopt a layered space time structure (BLAST, Bell Labs Layered Space Time) to form multiple parallel subchannels, improve channel capacity in the form of spatial multiplexing, and realize high-rate wireless communication.

The signal bandwidth of the broadband wireless communication system is larger than the channel-related bandwidth, and the fading of different frequency components in the signal is uncorrelated, and has frequency selectivity, and the corresponding time domain signal is distorted, thereby causing Inter Symbol Interference (ISI). Traditional narrowband systems generally use single-carrier time-domain equalization to eliminate inter-symbol interference. Recently, the demand for data transmission rates of various new services has increased rapidly, but the spectrum efficiency has not been improved, so wireless transmission The trend of broadbandization has become more apparent. Single-carrier time-domain equalization is applied to broadband systems. The number of taps required by the filter is too large, and the system complexity is too high to be realized. Orthogonal Frequency Division Multiplexing (OFDM) can transform Frequency-Selective into a number of flat Fading Fadings, which can effectively suppress ISI. By introducing discrete Fourier transform (DFT) and cyclic prefix (CP, Cyclic Prefix), the signal detection of OFDM system requires only one-tap equalization, which greatly reduces the complexity of the system. The MIMO-OFDM system combines the advantages of multiple antennas and multiple carriers to increase system capacity and reliability in frequency selective channels. MIM0-0FDM technology has been applied to the next-generation wireless communication standards 3GPP LTE and WiMax, which require wireless systems to support high-speed mobile users at 300 km/h.

In the MIM0-0F drawing system model, the system is configured with 1 ^ transmitting antenna and 1 ^ receiving antenna. The transmitter first transforms the serial bit sequence into a parallel bit stream, performs channel coding, interleaving, MPSK (QAM) symbol mapping, then inserts pilot symbols in the frequency domain, performs OFDM modulation, and finally adds a cyclic prefix to form an OF picture symbol. The cyclic prefix can eliminate inter-symbol interference caused by multipath fading, and can change the equivalent baseband digital channel from "linear convolution" to "circular convolution". The length of the cyclic prefix should be greater than the maximum delay spread of the channel. The OF ray symbol is transmitted by the corresponding antenna. When the transmitter, receiver or reflector moves, the channel will change rapidly due to multipath fading and Doppler effect, and interference will occur between the OF 载子 carriers.

The receiver first removes the cyclic prefix from the received signal, performs OF demodulation, and then uses the pilot received signal to estimate the current channel state information (CSI, Channel State Information), and then performs frequency domain equalization.

The subscript indicates the sequence number of the receiving antenna, and the subscript indicates the sequence number of the OFDM symbol subcarrier. After removing the cyclic prefix, after the FFT transform, the received signal on the subcarrier can be expressed as: (1)

A frequency domain received signal representing a subcarrier on the receiving antenna, indicating a symbol carried by a subcarrier of the transmitting antenna p, which is a frequency domain white Gaussian noise (ATCN) on the receiving antenna subcarrier, and ^M represents a transmitting antenna p and a receiving antenna ^ The frequency channel response coefficient between the first path on the subcarrier, the number of separable paths of the channel is Z, and the length of the discrete Fourier transform is ^defined·=. The first term and the second term in equation (1) represent useful signal and inter-subcarrier interference, respectively. Channel state information is required for equalization, inter-subcarrier interference cancellation, and adaptive modulation coding. Therefore, channel estimation is very necessary in wireless systems, and the accuracy of estimation directly affects the performance of the receiver. An iterative channel estimation algorithm based on single-antenna OFDM system that can suppress inter-subcarrier interference. The following content is included: First, the current channel estimation value is predicted by using the estimated channel state information of the previous OF symbol. The predicted value of the first symbol is expressed as 3⁄4^+7, the channel state information of the kth symbol is represented as w, and the first derivative thereof is expressed as, is a weighting coefficient. The predicted value can be obtained by the following formula:

h _p (k + l) = h(k) + rh'(k) Using the pilot of the OF system, channel estimation is performed, and the current channel state information Ji _c (k +1) can be obtained. Based on the pilot's estimated value f3⁄4 +7, and the predicted value (3⁄4 + for linear interpolation, the initial (pre-iteration) channel state information + 7 h _t (k + l) = a _k+l h _p (k + l + (l - a _k+l )h _c (k + 1) The receiver performs equalization and inter-subcarrier interference cancellation based on the initial channel estimation value, and outputs a symbol vector after the decision.

Feedback S to the channel estimator, iterative channel estimation is performed as follows: h(k + l) = (^- F ^H S ^H SF + R ¹ ) - ¹ F ^H S ^H y

N.

In the above formula, ^t + ^ is the iterative channel estimate, F is the Fourier transform matrix, S = diag(s), the channel autocorrelation matrix is represented as R = E[ , and the received symbol vector is represented as y. The performance of the receiver, the MIM0-0FDM system is no exception.

In the process of implementing the present invention, the inventors have found that at least the following technical problems exist in the prior art: In the prior art, when performing channel estimation, especially when performing channel estimation on a high-speed mobile communication system, the channel estimation value thereof is obtained. Less accurate. Summary of the invention It is an object of embodiments of the present invention to provide a channel estimation method, apparatus, and communication system, and a channel estimation method for a multi-antenna communication system to improve channel estimation accuracy.

To achieve the above object, an embodiment of the present invention provides a channel estimation method, including: acquiring a received signal, where the received signal includes a received pilot signal and a received data signal; according to the received pilot signal and an initial channel. The estimation matrix obtains an initial channel estimation value, where the initial channel estimation matrix includes interference information between subcarriers;

Iterative channel estimation is performed based on the initial channel estimate and the acquired received signal to obtain subsequent channel estimates.

Embodiments of the present invention provide a channel estimation method for a multi-antenna communication system, which performs channel estimation on an independent channel between each pair of transmit antennas and receive antennas according to the above-described channel estimation method.

The embodiment of the invention further provides a channel estimation apparatus, including:

a signal acquisition module, configured to acquire a received signal, where the received signal includes a received pilot signal and a received data signal;

a first channel value acquiring module, configured to acquire an initial channel estimation value according to the received pilot signal and an initial channel estimation matrix, where the initial channel estimation matrix includes interference information between subcarriers, and a second channel value acquiring module, configured to The initial channel estimate and the acquired received signal are iteratively channel estimated to obtain subsequent channel estimates.

Embodiments of the present invention also provide a communication system including the above channel estimation apparatus. The channel estimation method, device and communication system provided by the above embodiments of the present invention consider the influence of inter-subcarrier interference in the channel estimation process, can improve the accuracy of channel estimation, and effectively suppress inter-subcarrier interference, especially for high-speed mobile communication. The channel estimation scheme provided by the embodiment of the present invention has a more significant effect. DRAWINGS

1 is a schematic flowchart of an embodiment of a channel estimation method according to the present invention;

2 is a schematic structural diagram of an embodiment of a channel estimation apparatus according to the present invention; FIG. 3 is a schematic diagram of simulation in a specific embodiment of the present invention. detailed description

The technical solution of the present invention will be further described in detail below through the accompanying drawings and embodiments. In wireless communication systems, especially for high-speed mobile communication systems, the communication signals are more affected by the inter-subcarrier interference caused by the Doppler effect. The above-mentioned inter-subcarrier interference affects the accuracy of channel estimation. The embodiment of the present invention provides a channel estimation method, which considers interference between sub-carriers when performing channel estimation. FIG. 1 is a schematic flowchart of a channel estimation method according to an embodiment of the present invention. As shown in FIG. 1, the method includes the following steps:

Step 101: Acquire a received signal, where the received signal includes a received pilot signal and a received data signal. This embodiment is a pilot-based channel estimation method, where a pilot signal is inserted into a subcarrier at a data transmitting end. , transmitted to the receiver through a transmission channel;

Step 102: Acquire an initial channel estimation value according to the received pilot signal and an initial channel estimation matrix, where the initial channel estimation matrix includes interference information between subcarriers. On the basis of acquiring the pilot frequency signal, according to the inclusion The initial channel estimation matrix of the carrier interference information acquires an initial channel estimation value, where the initial channel estimation matrix includes inter-subcarrier interference information generated by the multi-antenna OF picture system under the fast fading channel, and is used for initial channel estimation for eliminating inter-subcarrier interference. Step 103: Perform iterative channel estimation according to the initial channel estimation value and the acquired received signal to obtain a subsequent channel estimation value.

Based on the obtained initial channel estimation values, the iterative channel estimation processing method can be used to continue channel estimation and obtain subsequent channel estimation values. The inter-subcarrier interference information in the embodiment of the present invention refers to interference generated between different subcarriers in a multicarrier communication system, for example, inter-subcarrier interference caused by the Doppler effect in a high speed mobile communication system.

In the above channel estimation method, the first channel estimation is a pilot-based channel estimation method, that is, obtaining an initial channel estimation value; the subsequent channel estimation is a subsequent channel obtained by iterative channel estimation based on the result of the previous channel estimation. estimated value. The letter provided by the above embodiment of the present invention In the channel estimation process, the influence of the inter-subcarrier interference is considered in the channel estimation process, and the accuracy of the channel estimation can be improved, and the inter-subcarrier interference can be effectively suppressed. Especially for the high-speed mobile communication system, the channel estimation method provided by the embodiment of the present invention has More significant results.

The step 103 of the foregoing embodiment may include the following steps: performing decoding processing on the received signal according to the initial channel estimation value to obtain a first decoded output value; and acquiring a first channel estimate according to the first decoded output value a matrix; obtaining a channel estimation value according to the first channel estimation matrix and the received signal. After the initial channel estimation value is obtained, the received signal is detected and decoded according to the value, and the first decoded output value including the pilot and the data symbol is obtained, and the first decoded output value is fed back to the channel. The estimating device recalculates and acquires the first channel estimation matrix according to the first decoded output value, and acquires the channel estimation value according to the first channel estimation matrix and the acquired received signal including the pilot and the data.

The above steps are the first step of the iterative signal estimation process, that is, the first channel estimation value is iteratively obtained from the initial channel estimation value, and the subsequent channel can be obtained by using the same iterative processing method according to the channel estimation value obtained in the above step. The estimation value may specifically include the following steps: decoding the received signal according to the channel estimation value obtained by the first channel estimation matrix and the received signal to obtain a second decoded output value;

Obtaining a second channel estimation matrix according to the second decoded output value;

A subsequent channel estimation value is obtained according to the second channel estimation matrix and the received signal.

In the foregoing embodiment, obtaining the initial channel estimation value according to the received pilot signal and the initial channel estimation matrix may be specifically:

h = Q y _p , where is the initial channel estimate, ρ ⁺ is the initial channel estimation matrix, which is the pilot received signal of the receiver. The above initial channel estimation matrix includes inter-subcarrier interference information.

The obtaining the channel estimation value according to the first channel estimation matrix and the received signal may be specifically as follows:

h = Q ⁺ y , where is the channel estimate, the first channel obtained from the initial channel estimate The estimation matrix is a received signal including pilot and transmission data.

The foregoing obtaining the channel estimation value according to the second channel estimation matrix and the received signal may be specifically: where is a channel estimation value, and decoding is performed according to the channel estimation value obtained by the first channel estimation matrix and the received signal. The second channel estimation matrix obtained later is a received signal including pilot and data.

The channel estimation method provided by the above embodiments of the present invention considers the influence of inter-carrier interference when performing channel estimation, so that the channel estimation value is more accurate, especially for the communication effect between high-speed mobile users.

The embodiment of the present invention further provides a channel estimation method for a multi-antenna communication system, that is, channel estimation is performed for each independent channel between each pair of transmit antennas and receive antennas according to the channel estimation method provided in the above embodiment. For example, for a MIMO multi-input and multi-output communication system, channel estimation is performed on four channels in accordance with the above-described channel estimation method.

Corresponding to the above-mentioned channel estimation method, the embodiment of the present invention further provides a channel estimation apparatus, and FIG. 2 is a schematic structural diagram of an embodiment of the channel estimation apparatus according to the present invention. As shown in FIG. 2, the channel estimation apparatus includes a signal acquisition module 11, The first channel value acquisition module 12 and the second channel value acquisition module 13 are configured to acquire a received signal, where the received signal includes the received pilot signal and the received data signal; the first channel value acquisition module 12 is configured to obtain an initial channel estimation value according to the received pilot signal and the initial channel estimation matrix, where the initial channel estimation matrix includes interference information between subcarriers; and the second channel value obtaining module 13 is configured to use the initial channel estimation. The value and the acquired received signal are iteratively channel estimated to obtain subsequent channel estimates.

The channel estimation apparatus provided by the embodiment of the present invention considers the influence of inter-subcarrier interference in the channel estimation process, can improve the accuracy of channel estimation, and effectively suppress inter-subcarrier interference, especially for a communication system supporting high-speed mobile users. More significant results.

In addition, the second channel value acquiring module in the foregoing embodiment may specifically include a first acquiring unit, a second acquiring unit, and a third acquiring unit, where the first acquiring unit is configured to decode the received signal according to the initial channel estimation value. Obtaining a first decoded output value; the second obtaining unit is configured to perform according to the a first channel estimation matrix obtained by the first decoding output value; a third acquiring unit, configured to acquire a subsequent channel estimation value according to the first channel estimation matrix and the received signal. The first decoded output value obtained according to the initial channel estimation value in the technical solution, and the first decoded output value feedback is re-channel estimation, the channel estimation value is obtained, and the first obtained according to the first decoded output signal is obtained. The second channel value acquisition module further includes: a fourth acquisition unit, a fifth acquisition unit, and a sixth acquisition unit, where the channel estimation matrix includes inter-subcarrier interference information, and the obtained channel estimation value effectively suppresses interference between sub-carriers. The fourth obtaining unit is configured to decode the received signal according to the channel estimation value obtained by the first channel estimation matrix and the received signal to obtain a second decoded output value; and the fifth obtaining unit is configured to use the second Decoding the output value to obtain a second channel estimation matrix including inter-subcarrier interference information; the sixth obtaining unit is configured to obtain a channel estimation value according to the second channel estimation matrix and the received signal. The technical solution provides continuous channel estimation by an iterative processing method, and the subsequent channel estimation matrix obtained at each channel estimation includes inter-subcarrier interference information, and the above-mentioned signal estimation value can effectively suppress inter-subcarrier interference. .

The channel estimation apparatus provided by the above embodiments of the present invention may be provided in a multi-antenna communication system. Embodiments of the present invention also provide a communication system including the above-described channel estimation apparatus. The channel estimation apparatus considers the influence of inter-subcarrier interference in the channel estimation process, can improve the accuracy of channel estimation, and effectively suppress inter-subcarrier interference, and is particularly effective for a communication system supporting high-speed mobile users.

The communication system provided by the above embodiment of the present invention, wherein the channel estimation apparatus can be disposed at a receiver or a transmitter.

The following is a specific embodiment to illustrate the technical solution of the present invention. In this embodiment, a single antenna orthogonal frequency division multiplexing system is first taken as an example for analysis, and then extended to a multi-antenna system.

(A) indicates the symbol carried by the (k)th subcarrier on the (single) antenna, and the transmission vector can be expressed as:

x = [x(0), - , x(n), - , x(N - l)f ( 1 ) The length of the DFT transform is N. After the IFFT transform, the generated time-sampled value vector of the OF symbol is:

x' = F ^H x = [x '(0), X '(1), ',,χ\Ν- l)f

Where F is the TVxTV Fourier transform matrix:

In this embodiment, the data block is added with a guard interval, which can eliminate inter-symbol interference ISI caused by multipath fading. Meanwhile, in order to form a "circular convolution" effect of the channel, the tail data of the OFDM symbol can be copied to the guard interval to form a loop. The prefix, whose length should be greater than the maximum time extension V of the channel. The complete OFDM symbol time domain sample value is:

G + N) <n<G

x(n) =

x\nG) G<n<n + G-\ x(n) , 0≤"≤G-1 is the cyclic prefix. After the OF symbol is subjected to the frequency selective fast fading channel, at the sampling time?, the received signal can be Expressed as: r(n) = ^ h(n, l)x(n - /) + w(n) ( 2 )

//(«,/) indicates the sample value of the /path at time in the time-varying multipath channel, which is the number of paths, which is the sample value of the Gaussian white noise AWGN at time ?, and its frequency domain value is expressed as . After removing the cyclic prefix and performing FFT transformation, the expression of the received signal is:

1

^ h(n, l)x(n -/) + w(n)

1

Dx( )e~^~e~ + w(k) The channel can be approximated as linear in fast fading. This approximation has little effect on the accuracy of channel estimation. When the normalized Doppler shift is less than 0.2, the channel is The effects of autocorrelation properties are also negligible. Assuming that the fast fading channel changes linearly within an OF ray, the sampled value of the channel arbitrarily / / («, /) can be decomposed into the sum of the mean h _a (i) and the slope value h ), as shown in the following equation: h(n, 1) = h _a (/) + (n- ^-) h _s (/) ( 4 ) Bring the equation (4) into equation (3), the received signal can be expressed as:

1

N-l

)h _s (l)x(m)e + w(k)

JV _M= o /=o According to mathematical theory, J ~ ^ ~ = 0, so ( a ) and ( b ) in equation ( 5 ) can be further simplified to:

,

= ∑∑∑ (" -" {l)x{m)e~^~e~

TV-1

∑("-"-) ^e h _s (l)x(m)e

(a) and (b) brought in (5), derived

(k - m) i person Γ {Ι ~^ (k = m)

+ 1 + w(k) h _s (l)x(m)e (k≠ m)

0,

(k≠m) The above formula can be expressed more simply as:

7(k) = h _s (l)x(m)e ^N +w(k) (8)

The wireless wideband channel under high-speed movement is a fast fading, frequency selective channel, and the fast fading will produce a spread, so that the channel will change rapidly. For the OFL system, the channel fading experienced by the adjacent OF picture will have a large change. , not relevant. Therefore, a pilot scheme is employed for channel estimation, and pilot symbols are inserted in each OF symbol. Under high-speed movement, Doppler spread will cause inter-carrier interference between OF匪, and the pilot symbols will also be interfered by adjacent sub-carriers. So at high speed When moving the channel estimation of the OF picture, in order to improve the accuracy of the channel estimation, not only the noise but also the inter-subcarrier interference should be considered.

Let each OF picture symbol have M≥2v) pilots, which are respectively inserted into subcarriers p(l), p(2), ..., p(). Here, ρ(0, = 1, .., Μ is the serial number of the subcarrier. According to equation (8), after OF demodulation, the received signal of the pilot subcarrier is:

= 1,···, (9) Let the received signal vector be: =[ P(I)), P(2)), the pilot symbol vector is: x _p =[x(p(\)), x( p(2)X x(p(M))] ^T ; the vector of Gaussian white noise in the frequency domain is expressed as w _p =[w(p(\ w(p(2% w(p(M))) ^T ; The time domain mean vector and slope value vector of the channel are expressed as:

K =[h _a {Q), h _a {\), ... h _a (vl)] , h _s =[h _s (0), _s (l), ... h _s (vl)] ^T ; The Fourier transform coefficients can be expressed as a vector form:

Express equation (9) as a matrix:

m^ ^ot x(m)a(m)

2-,

x(p(l) p(l)) e

h + h.+e ( 10) (ρ(Μ)) _Ά {ρ(Μ)) x(m)a(m)

The two specific matrices in equation (10) can be represented as letters: A-- (11)

Equation (10) is reduced to the following matrix form:

y _p ^Ah _a +Bh _s +e^Qh+e ( 12)

Where 0 = μ Β] , the channel vector / i = [/i _a /i _s f, the error vector of the channel estimate is:

Using the ZF (Zero Forcing) criterion, the channel vector can be calculated by the following formula: h = Q _p ( 14)

Q is a Moor e-Penr 0 se generalized inverse matrix form, that is, the initial channel estimation matrix mentioned in the above embodiment can be expressed as: Q = (Q ^H Q) ^l Q ^H

Obtained in the above formula (14) is the initial channel estimation value of the single antenna OF system without iteration, using this value for signal detection and decoding, and the decoded soft output signal is fed back to the channel estimation device, and the channel estimation can be performed again. , can get more accurate channel state information. It can be seen from the above equation (13) that the channel estimation error is related to noise and inter-subcarrier interference. In the initial channel estimation, the data information is not considered, so the influence of the data subcarrier on the pilot is not considered. In the present invention, the decoder soft output signal is fed back to the channel estimation device, and after channel estimation is repeated, the channel can be improved. The accuracy of the channel estimation. The decoded soft output signal including pilot and data symbols is represented as x-[x(l)−x(Nf, according to equation (8), the frequency domain subcarrier (including pilot and transmission data) received signal vector can be expressed as :

Where = [ 1), (2), ..., M)f is the frequency domain vector form of the Gaussian white noise channel. The matrix in the above formula is replaced by the alphabetic symbol:

A =

Equation (15) can be reduced to the alphabetic matrix form: y = Ah _a + Bh _s +w = + w = Qh + w ( 16 )

The iterative channel estimation also adopts the zero-forcing criterion, and the channel vector calculation method is as follows:

h = Q ⁺ = (Q ^H Q) ^l Q ^H ( 17 )

The following equation (17) is the subsequent channel estimation matrix mentioned in the above embodiment, that is, the received signal including the pilot signal and the data signal mentioned in the above embodiment.

The single antenna iterative channel estimation method proposed by the present invention can be extended to a multi-antenna system. In a multi-antenna system, the pilot subcarriers are not only affected by noise and inter-subcarrier interference, but also interference from other transmit antennas. If the pilot positions on different antennas are different, inter-antenna interference can be avoided. After excluding inter-antenna interference, the initial channel estimation value of the MIM0-0FDM system is estimated according to the method of initial channel estimation of the single-antenna OFDM system, as shown in equation (14). MIM0-0FDM The antenna in the system (the serial number of the received signal can be expressed as:

\<p<M ₁

(18) y, =∑

\<q<M _R

Where ^^[^(1),^(1),,", (^)] represents the received signal vector after OFDM demodulation on the antenna,

The channel mean and slope value vectors between the transmit antenna p and the receive antenna ^ are expressed as: h' ^q - [h _a ^p ' ^q (0), h _a ^p ' ^q (1), · - , h _a ^p ' ^q ( - 1)] ^Γ , h _s ^p ' ^q h _s ^p ' ^q {\), " - h^' ^q (vl) , the frequency domain noise vector on the receiving antenna is expressed as: =[v _3⁄4 (l ), v _3⁄4 ( ² ), '-', w(iV)] ^T

The iterative method of the MIM0-0F drawing system is the same as in the single antenna, using the decoded soft output signal as the feedback reference signal. Equation (18) can be rewritten as an expression containing pilot and data symbols as follows:

Among them, ^

According to the foregoing method of single antenna, it can be known that the calculation formula of the channel estimation of the MIM0-0F system is:

The above is the estimated value of the signal on the antenna (1, ^ is the channel estimation moment of the acquired antenna q) The channel estimation matrix includes inter-subcarrier interference information, and ^ is a received signal including a pilot signal and a data signal on the antenna q.

The channel estimation method provided by the foregoing embodiment of the present invention is applicable to a case where there is strong inter-subcarrier interference between multiple carriers under high-speed mobile conditions. The following is a channel estimation simulation in the MIM0-0FDM system, where simulation parameters can be set. as follows:

In this embodiment, a pilot design scheme for suppressing subcarrier interference is adopted, and the scheme is A set of pilots is inserted at equal intervals on the OFDM subcarriers. In the simulation, two pilots are selected for each pilot group, and P represents the pilot number of each group, that is, P=2, and V represents the pilot symbol to data symbol power ratio. The number of iterations of the channel estimation is expressed as I ter , and the number of iterations in the simulation is 0, 1, 2, 3, respectively. When the parameter is 0, it means that no iteration is used. The BER (Bit Error Rate) - SNR (Signal to Noise Ratio) performance for different iterations is shown in Figure 3. The iterative channel estimate has a performance gain of about 1.5 dB when the pilot and data symbol transmit powers are equal. As the number of iterations increases, the gain produced by one iteration becomes smaller and smaller. As shown in Figure 3, the second iteration is closer to the performance of the first iteration. The complexity of the receiver is positively related to the number of iterations. To achieve optimal performance and complexity balance, 2 iterations can be used in this configuration.

The channel estimation method, device and system provided by the above embodiments of the present invention consider the influence of inter-subcarrier interference in the channel estimation process, can improve the accuracy of channel estimation, and effectively suppress inter-subcarrier interference, especially for high-speed mobile communication systems. The channel estimation scheme provided by the embodiment of the present invention has a more significant effect. The above technical solution can be applied not only to a single antenna communication system but also to MIM0-0F drawing. It should be noted that the above embodiments are only intended to illustrate the technical solutions of the present invention and are not to be construed as limiting the embodiments of the present invention. The technical solutions of the present invention may be modified or equivalently substituted, and the modified technical solutions may not deviate from the spirit and scope of the technical solutions of the present invention.

Claims

Claim

A channel estimation method, comprising:

Obtaining a received signal, where the received signal includes a received pilot signal and a received data signal; acquiring an initial channel estimation value according to the received pilot signal and an initial channel estimation matrix, where the initial channel estimation matrix includes between subcarriers Interference information;

The channel estimation method according to claim 1, wherein the performing the iterative channel estimation according to the initial channel estimation value and the acquired received signal to obtain the subsequent channel estimation value comprises: receiving the initial channel estimation value according to the Decoding a signal to obtain a first decoded output value; acquiring a first channel estimation matrix according to the first decoded output value;

A channel estimation value is obtained according to the first channel estimation matrix and the received signal.

3. The channel estimation method according to claim 2, further comprising: decoding the received signal according to the channel estimation value obtained by the first channel estimation matrix and the received signal to obtain a second decoding output. Value

A channel estimation value is obtained according to the second channel estimation matrix and the received signal.

The channel estimation method according to claim 1, wherein the obtaining the initial channel estimation value according to the received pilot signal and the initial channel estimation matrix is specifically:

h = Q y _p , where is the initial channel estimate, ρ ⁺ is the initial channel estimate matrix including inter-subcarrier interference information, and _Λ is the received pilot receive signal.

The channel estimation method according to claim 2, wherein the obtaining the channel estimation value according to the first channel estimation matrix and the received signal is specifically:

h = Q ⁺ y , where is the channel estimation value, and the first channel estimation matrix is obtained according to the initial channel estimation value, which is a received signal including pilot and data.

The channel estimation method according to claim 3, wherein the second letter is The channel estimation matrix and the received signal to obtain the channel estimate are:

h = Q ⁺ y , where is a channel estimation value, and the second channel estimation matrix obtained after decoding according to the channel estimation value obtained by the first channel estimation matrix and the received signal is a received signal including pilot and data .

7. A channel estimation method for a multi-antenna communication system, characterized in that, according to the claims

1-6 The channel estimation method of any of the methods performs channel estimation on each of a pair of independent channels between the transmitting antenna and the receiving antenna.

8. A channel estimation apparatus, comprising:

The channel estimation apparatus according to claim 8, wherein the second channel value acquisition module comprises:

a first acquiring unit, configured to decode the received signal according to the initial channel estimation value to obtain a first decoded output value;

a second acquiring unit, configured to acquire a first channel estimation matrix according to the first decoding output value, and a third acquiring unit, configured to acquire a subsequent channel estimation value according to the first channel estimation matrix and the received signal.

The channel estimation apparatus according to claim 9, wherein the second channel value acquisition module further comprises:

a fourth acquiring unit, configured to decode the received signal according to the channel estimation value obtained by the first channel estimation matrix and the received signal to obtain a second decoded output value;

a fifth acquiring unit, configured to acquire, according to the second decoded output value, an inter-subcarrier interference signal Second channel estimation matrix;

And a sixth acquiring unit, configured to acquire a channel estimation value according to the second channel estimation matrix and the received signal.

The channel estimating apparatus according to any one of claims 8 to 10, wherein said channel estimating means is provided in a multi-antenna communication system.

A communication system, comprising the channel estimation apparatus of claims 8-10.

A communication system according to claim 12, wherein said channel estimation means is provided at a receiver or a transmitter.