CN101702702B - Symbol synchronizing method and device and symbol receiving processing system - Google Patents

Abstract

The embodiment of the present invention discloses a symbol synchronization method and device, and a receiving and processing system. The method includes: receiving the signal sent by the transmitting end, obtaining the position information and power information of each path in the current OFDM symbol, and obtaining the feedback for all OFDM symbols The estimated variance of ; according to the preset start position set or the start position ms of all FFT integration intervals in the quantized start position set, the obtained position information and power information of each path and the estimated variance for all OFDM symbol feedback , to obtain the total residual interference energy of all paths in the current OFDM symbol; obtain the starting position corresponding to the minimum interference energy in the total residual interference energy; use the starting position corresponding to the minimum interference energy as the symbol timing value, and perform Symbol synchronization. The embodiment of the present invention can reduce the residual interference energy after IBI cancellation and ICI reconstruction compensation in the case that the channel delay extension exceeds the CP length.

Description

Symbol synchronization method and device, receiving and processing system

technical field

The invention relates to communication technology, in particular to a symbol synchronization method and device, and a receiving and processing system. the

Background technique

Orthogonal Frequency Division Multiplexing (OFDM) converts the frequency-selective multipath fading channel into a flat channel in the frequency domain, thereby reducing the impact of multipath fading and improving spectrum utilization. However, the OFDM system is extremely sensitive to synchronization errors and has high requirements for time synchronization. In terms of frequency synchronization, frequency offset will introduce Internal Channel Interference (ICI) and deteriorate the signal-to-noise ratio of each subcarrier, thus deteriorating the transmission performance of the entire communication system. Errors in frame synchronization will introduce InterSymbol Interference (InterSymbol Interference, hereinafter referred to as: ISI), that is, intersymbol interference, and will also have a serious impact on channel estimation. In the existing OFDM system, the following three types of synchronization methods are mainly adopted: symbol timing synchronization, carrier synchronization and sampling clock synchronization. the

To realize OFDM signal synchronization, it is necessary to find the starting position and carrier offset of OFDM symbols. OFDM modulation technology is a multi-carrier technology, and multi-carrier systems are more sensitive to timing deviations than single-carrier systems. In the single carrier frequency domain equalization (single carrier frequency domain equalization, hereinafter referred to as: SC-FDE) system of the OFDM system and frequency domain equalization, the ISI caused by multipath is eliminated by inserting a cyclic prefix (Cyclic Prefix, hereinafter referred to as: CP). Since OFDM system and SC-FDE system adopt CP, when the length of CP is greater than the multipath delay extension of the channel, there will be a non-interference area in CP, that is, no ISI area, and frequency domain can be used in the non-interference area. The estimated method corrects for the phase rotation of the desired signal. Therefore, within the scope of the non-interference zone, the OFDM symbol will not be affected by the ISI from the previous OFDM symbol caused by the multipath channel. Outside the non-interference zone, timing errors will cause inter-block interference (Inter Block Interference, hereinafter referred to as: IBI) and ICI to the OFDM system and the SC-FDE system. At the same time, it will cause attenuation and phase rotation of useful signals. More seriously, it will seriously affect the performance of the channel estimator, thus increasing the channel estimation variance. the

In the prior art, the Residual Inter Symbol Interference Clutter (Residual Inter Symbol Interference Clutter, hereinafter referred to as: RISIC) algorithm is usually used to reconstruct the IBI caused by the preceding and following OFDM symbols, and from the received signal of the current OFDM symbol in the corresponding integration interval Subtract, and reconstruct the missing part of the current OFDM symbol, and fill in the signal of the corresponding integration interval, thereby suppressing IBI and ICI. the

However, when the existing technology uses the RISIC algorithm to suppress IBI and ICI, when the channel delay extension exceeds the CP length, the synchronization of OFDM symbols cannot be effectively realized, thereby reducing the receiving performance of the receiver, such as: bit errors in data transmission rate, symbol error rate, or block error rate performance. the

Contents of the invention

Embodiments of the present invention provide a symbol synchronization method and device, and a receiving and processing system. When the channel delay extension exceeds the CP length, the residual interference energy after IBI cancellation and ICI reconstruction compensation is reduced, thereby effectively realizing OFDM symbols. synchronization to improve receiver performance. the

A symbol synchronization method provided by an embodiment of the present invention mainly includes:

Receive the signal sent by the sending end, obtain the position information and power information of each path in the current OFDM symbol in the signal, and obtain the estimated variance for all OFDM symbol feedback;

According to the preset start position set or the start position of all fast Fourier transform integration intervals in the quantized start position set, the obtained position information and power information of each path and the estimated variance for all OFDM symbol feedback, Obtain the total residual interference energy of all paths in the current OFDM symbol;

Obtain the starting position corresponding to the minimum interference energy in the total residual interference energy;

The starting position corresponding to the minimum interference energy is used as the symbol timing value to perform symbol synchronization on the signal sent by the transmitting end. the

A symbol synchronization device provided in an embodiment of the present invention mainly includes:

The first obtaining module is used to receive the signal sent by the transmitting end, obtain the position information and power information of each path in the current OFDM symbol in the signal, and the estimated variance for all OFDM symbol feedback;

The second acquisition module is configured to use the preset start position set or the start position of all integration intervals in the quantized start position set, the position information and power information of each path acquired by the first acquisition module, and For the estimated variance of all OFDM symbol feedback, obtain the total residual interference energy of all paths in the current OFDM symbol;

The third acquisition module is used to acquire the starting position corresponding to the minimum interference energy in the total residual interference energy;

A symbol synchronization module, configured to use the starting position corresponding to the minimum interference energy as a symbol timing value to perform symbol synchronization on the signal sent by the transmitting end. the

A reception processing system provided by an embodiment of the present invention includes a channel estimation device, an inter-block interference elimination device, a cyclic prefix reconstruction device, a receiver, and the symbol synchronization device provided by the above-mentioned embodiments of the present invention, wherein,

The channel estimation device is used to perform channel estimation using signals received by the receiving end to obtain time-domain channel information of each path, the time-domain channel information including position information and channel factors of each path;

The inter-block interference elimination device is configured to, according to the time-domain channel information of each path and the decision value of the receiver for the previous OFDM symbol and the subsequent OFDM symbol of the current Orthogonal Frequency Division Multiplexing OFDM symbol, to the The symbol synchronization device performs inter-block interference IBI elimination on the signal after symbol synchronization;

The cyclic prefix reconstruction device is configured to perform CP reconstruction and compensation on the signal after IBI cancellation according to the time-domain channel information of each path and the decision value sent by the receiver for the current OFDM symbol;

The receiver is used to transform the time-domain signal after CP reconstruction and compensation into the frequency domain and perform receiving processing, generate the estimated variance for all OFDM symbol feedback and send it to the symbol synchronization device, and generate the current OFDM The judgment values of the previous and subsequent OFDM symbols of the symbol are sent to the inter-block interference elimination device, and the judgment value of the current OFDM symbol is generated and sent to the cyclic prefix reconstruction device. the

Based on the symbol synchronization method and device and receiving processing system provided by the above embodiments of the present invention, by obtaining the starting position corresponding to the minimum interference energy in the total residual interference energy, and using the starting position corresponding to the minimum interference energy as the symbol timing value, Symbol synchronization is performed on the signal sent by the transmitting end. Compared with the existing technology, the residual interference energy after IBI cancellation and ICI reconstruction compensation can be reduced when the channel delay extension exceeds the CP length, so as to effectively realize OFDM symbols Synchronization, improve the receiving performance of the receiver. the

The technical solutions of the present invention will be described in further detail below with reference to the accompanying drawings and embodiments. the

Description of drawings

Fig. 1 is a timing schematic diagram of multipath channel receiving signal;

Fig. 2 is a flowchart of an embodiment of the symbol synchronization method of the present invention;

Fig. 3 is the flow chart of another embodiment of symbol synchronization method of the present invention;

Fig. 4 is a schematic structural diagram of an embodiment of the symbol synchronization device of the present invention;

Fig. 5 is a schematic structural diagram of another embodiment of the symbol synchronization device of the present invention;

Fig. 6 is a schematic structural diagram of an embodiment of the receiving and processing system of the present invention;

Fig. 7 is the structural representation of another embodiment of the receiving processing system of the present invention;

Fig. 8 is a schematic diagram of a symbol error rate performance improvement after adopting the embodiment of the symbol synchronization method of the present invention;

FIG. 9 is a schematic diagram of a block error rate performance improvement after adopting an embodiment of the symbol synchronization method of the present invention. the

Detailed ways

As shown in FIG. 1 , it is a schematic diagram of a timing sequence of a signal received by a multipath channel. Taking three-path signals as an example, Figure 1 shows the composition of useful signals in multi-path channel received signals under multi-path delay extension, and shows the effect of the previous OFDM symbol and the next OFDM symbol on the current OFDM symbol IBI. In FIG. 1 , the ordinate h[m] represents a multipath channel, the minimum path position of the multipath delay spread is m _min , and the maximum path position is m _max . In FIG. 1 , signal 101 , signal 102 and signal 103 respectively represent signals corresponding to path 101 , path 102 and path 103 , which are obtained by delaying the transmission signal corresponding to the time delay of each path. Suppose m _s is the starting position of the fast Fourier transform (fastFourier transform, hereinafter referred to as: FFT) integration interval of the nth OFDM symbol, that is, the symbol timing position, where the nth OFDM symbol is also called the current OFDM symbol . In Fig. 1, horizontal dashed lines 104 and 105 represent the previous OFDM symbol of the current OFDM symbol, horizontal dashed lines 106 and 107 represent the next OFDM symbol of the current OFDM symbol, horizontal dashed lines 104 and 105 are in [m _s , m _s +K-1 ] is the IBI brought by the previous OFDM symbol to the current OFDM symbol, and the integral interval formed by the horizontal dotted lines 106 and 107 within the range of [m _s , m _s +K-1] is the subsequent For the IBI brought by an OFDM symbol to the current OFDM symbol, for the current OFDM symbol, the above two parts of the integration interval are missing, so that the signal corresponding to the path (also called the path signal) cannot obtain the current value of the complete integration interval length. OFDM symbols, or in other words, for the path signal, the CP is incomplete, which cannot guarantee the circular convolution characteristics between the transmitted signal and the channel, which will cause ICI in the frequency domain. For the signal corresponding to path 102, since there are no front and back OFDM symbols in the integration interval [m _s , m _s +K-1], there is no IBI and ICI. The signals corresponding to path 101 and path 103 are subjected to the IBI of the previous OFDM symbol and the next OFDM symbol respectively, and ICI exists in the frequency domain at the same time.

In the embodiment of the present invention, the starting position corresponding to the minimum interference energy in the total residual interference energy is used as the symbol timing value to perform symbol synchronization on the signal sent by the transmitting end, so that when the channel delay extension exceeds the CP length, the The residual interference energy after small IBI elimination and ICI reconstruction compensation can effectively realize the synchronization of OFDM symbols and improve the receiving performance of the receiver, such as improving the bit error rate, symbol error rate or block error rate performance of data transmission. The method, device and system provided by the embodiments of the present invention can be applied to any communication system, for example: in an OFDM system or a SC-FDE system, due to the fact that the multipath delay extension length is greater than the CP length, the CP is insufficient and the RISIC algorithm is used in the receiver Symbol synchronization at time. the

Fig. 2 is a flow chart of an embodiment of a symbol synchronization method according to the present invention, and the flow of this embodiment may be specifically implemented by a symbol synchronization device. As shown in Figure 2, the symbol synchronization method of this embodiment may include:

201. Receive a signal sent by a transmitting end, and acquire position information and power information of each path in a current OFDM symbol in the signal, and estimated variances fed back for all OFDM symbols. the

Specifically, the estimated variance for feedback of all OFDM symbols is also the estimated variance of decision feedback time-domain symbols for all OFDM symbols, where the decision feedback time-domain symbols are also referred to as decision feedback values. the

Specifically, the position information and power information of each path may be acquired through a multipath search method or a tracking method. the

202. According to the preset start position set or the start position m _s of all FFT integration intervals in the quantized start position set, the obtained position information and power information of each path, and the estimated variance for all OFDM symbol feedback , to obtain the total residual interference energy of all paths in the current OFDM symbol.

203. Obtain a starting position corresponding to the minimum interference energy in the total residual interference energy. the

204. Using the starting position corresponding to the minimum interference energy as the symbol timing value, perform symbol synchronization on the signal sent by the sending end. the

Specifically, the symbol timing value corresponding to the start position corresponding to the minimum interference energy can be used to extract the corresponding OFDM symbol from the signal sent by the sender, so as to realize the symbol synchronization of the signal sent by the sender. the

In the symbol synchronization method of the embodiment of the present invention, the starting position corresponding to the minimum interference energy in the total residual interference energy is used as the symbol timing value to perform symbol synchronization on the signal sent by the transmitting end, so that when the channel delay extension exceeds the CP length Under this condition, the residual interference energy after IBI elimination and ICI reconstruction compensation is reduced, so as to effectively realize the synchronization of OFDM symbols and improve the receiving performance of the receiver, such as: improving the bit error rate, symbol error rate or block error rate performance of data transmission wait. the

Fig. 3 is a flow chart of another embodiment of the symbol synchronization method according to the present invention, and the flow of this embodiment may also be specifically implemented by a symbol synchronization device. As shown in Figure 3, the symbol synchronization method of this embodiment may include:

301. Receive a signal sent by a sending end. the

Wherein, the received signal may be referred to as a received signal. For OFDM systems, the received signal includes useful signal and noise. Specifically, the received signal can be expressed as:

r _n [m] = z _n [m] + n [m] (1)

In formula (1), r _n [m] represents the n-th OFDM symbol at the m-th sampling time in the received signal, and z _n [m] represents the n-th OFDM symbol at the m-th sampling time sent by the sender useful signal, n[m] represents the noise in the nth OFDM symbol at the mth sampling moment. where z _n [m] can be represented by:

${\mathrm{<span\; class="notranslate">\; z</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; h</span>}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; *</span>\underset{\mathrm{<span\; class="notranslate">\; l</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0</span>}}{\overset{<span\; class="notranslate">\; +</span><span\; class="notranslate">\; \&infin;</span>}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; l</span>}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; ln</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; h</span>}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; *</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; h</span>}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; *</span>\underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{<span\; class="notranslate">\; +</span><span\; class="notranslate">\; \&infin;</span>}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; l</span>}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; ln</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

表示后续符号块带来的IBI，N表示OFDM符号的符号块长度，h[m]为等效离散信道因子，可以表示为：  In formula (2), x _n [m] represents the mth time-domain sample point signal corresponding to the nth OFDM symbol,

Represents the IBI brought by subsequent symbol blocks, N represents the symbol block length of OFDM symbols, h[m] is the equivalent discrete channel factor, which can be expressed as:

$\mathrm{<span\; class="notranslate">\; h</span>}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; =</span>\underset{\mathrm{<span\; class="notranslate">\; i</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}{\mathrm{<span\; class="notranslate">\; \&gamma;</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}\mathrm{<span\; class="notranslate">\; \&delta;</span>}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$

In formula (3), m _i is the time delay of the i-th path, γ _i is the channel factor of the i-th path, and δ represents the impact function.

302. Acquire position information m _i and channel factor γ _i of each path in the current OFDM symbol through channel estimation, and acquire power information |γ _i | ² of each corresponding path according to channel factor γ _i . Among them, i represents the i-th path, which is an integer greater than zero.

303. Receive estimated variances fed back by the receiver for all OFDM symbols. the

Take σ _n ² as the estimated variance fed back by the receiver for the nth OFDM symbol. In this embodiment of the present invention, the nth OFDM symbol is used as the current OFDM symbol.

The estimated variance for OFDM symbol feedback is also referred to as the estimated variance of decision feedback symbols. Among them, the receiver can obtain the estimated variance for all OFDM symbol feedback through a variety of detection methods, for example: through the decision feedback method, the estimated variance of the OFDM symbol feedback can be obtained at the same time, and the estimated variance can be used to characterize the reliability of the receiver decision feedback sex. Specifically, the receiver in this embodiment may be an OFDM receiver. the

OFDM receivers are generally composed of detectors and decoders. Therefore, receivers generally have two corresponding feedback methods: one is "iterative receiver" feedback, that is, decoding feedback, which can be called outer iteration; One is block decision feedback, that is, iteration within the detector. the

The decoding feedback is taken as an example below to describe how to obtain the estimated variance of the decision feedback symbols. Wherein, the estimated variance of the decision feedback symbol is also referred to as the decision feedback value of the OFDM symbol. In the first iteration, except that the current OFDM symbol is the first OFDM symbol, for the current nth OFDM symbol, the decision feedback value of the previous OFDM symbol can be obtained. The estimated variance σ _n-1 ² of the previous OFDM symbol can be estimated by the detector in the OFDM receiver while judging the previous OFDM symbol. At this time, the decision feedback value of the current OFDM symbol and the next OFDM symbol is not available yet, it can be assumed that ${\mathrm{\&sigma;}}_{\mathrm{no}}^2={\mathrm{\&sigma;}}_{\mathrm{no}+1}^2={\mathrm{\&sigma;}}_{\mathrm{the\; <figure-callout\; id="2"\; label="s"\; filenames="H2009102218700E00051.png"\; state="\{\{state\}\}">s</figure-callout>}}^2,$ That is: the estimated variance of the current OFDM symbol and the subsequent OFDM symbol is equal to the power σ _s ² of the transmitted time-domain symbol. In subsequent iterations, the decision feedback value of the current OFDM symbol can be the decision feedback value of the previous iteration, or the updated detector decision value in this iteration, as long as the corresponding decision feedback symbol is estimated by the OFDM receiver Estimated variance σ _n-1 ² , and for the current OFDM symbol and subsequent OFDM symbols, the decision feedback value can be obtained from the previous iteration, and the corresponding symbol estimation variance is estimated at the same time when the decision feedback value is obtained in the previous iteration σ _n ² and σ _n+1 ² are fed back to the symbol synchronization device of this iteration.

In addition, it should be noted that for the first OFDM symbol, IBI elimination may not be performed. the

304. According to the preset start position set or the start position m _s of all FFT integration intervals in the quantized start position set, the position information and power information of each path, and the estimated variance for all OFDM symbol feedback, respectively obtain The total residual interference energy of all paths in the current OFDM symbol.

For each starting position m _s of all FFT integration intervals in the preset starting position set or the quantized starting position set, the total residual interference energy of all paths in a current OFDM symbol can be obtained respectively.

In the embodiment of the present invention, there are many ways to obtain the total residual interference energy of all paths in the current OFDM symbol, which can be $\mathrm{\&epsiv;}\left(m_{\mathrm{the\; s}}\right)=\underset{i}{\mathrm{\&Sigma;}}{l}_i\left(m_{\mathrm{the\; s}}\right){\left|{\mathrm{\&gamma;}}_i\right|}^2,$ It is also possible to further modify the above formula, for example, it may be as follows:

$\mathrm{<span\; class="notranslate">\; \&epsiv;</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\underset{\mathrm{<span\; class="notranslate">\; i</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}{\mathrm{<span\; class="notranslate">\; l</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; )</span>{<span\; class="notranslate">\; |</span>{\mathrm{<span\; class="notranslate">\; \&gamma;</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; |</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>\underset{{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; <</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; G</span>}}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; G</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; )</span>{<span\; class="notranslate">\; |</span>{\mathrm{<span\; class="notranslate">\; \&gamma;</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; |</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>\underset{{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; ></span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; )</span>{<span\; class="notranslate">\; |</span>{\mathrm{<span\; class="notranslate">\; \&gamma;</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; |</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; )</span>$

In formula (4), ε(m _s ) is the total residual interference energy of all paths in the current OFDM symbol, m _s is the symbol timing position of the nth OFDM symbol, l _i (m _s ) means that the symbol timing position is m _s When is the interference energy of the i-th path, N _G is the length of the cyclic prefix CP.

305. Obtain the minimum interference energy minε(m _i ) in the total residual interference energy, and obtain the starting position m _o corresponding to the minimum interference energy minε(m _i ) according to i _o =argminε(m _i ).

in, $m_o=m_{i_o},$ argminε(m _i ) represents a parameter that minimizes ε(m _i ).

306. Using the starting position m _o corresponding to the minimum interference energy in the total residual interference energy as the symbol timing value, perform symbol synchronization on the received signal.

Through the symbol synchronization method shown in the above-mentioned embodiments of the present invention, a series of operations such as subsequent IBI elimination, reconstruction and compensation of the missing CP part in the received signal, and receiving processing are performed on the received signal. the

If only considering the IBI caused by the previous OFDM symbol and the next OFDM symbol of the current OFDM symbol, the received signal can be expressed as:

$\mathrm{<span\; class="notranslate">\; r</span>}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; n</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; =</span>\underset{\mathrm{<span\; class="notranslate">\; l</span>}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1,0,1</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}\mathrm{<span\; class="notranslate">\; h</span>}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; ]</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; l</span>}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; n</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; l</span>}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; n</span>}<span\; class="notranslate">\; ]</span>$

$<span\; class="notranslate">\; =</span>\underset{\mathrm{<span\; class="notranslate">\; i</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}{\mathrm{<span\; class="notranslate">\; \&gamma;</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; +</span>\underset{{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; ></span>\mathrm{<span\; class="notranslate">\; m</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}{\mathrm{<span\; class="notranslate">\; \&gamma;</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; ]</span>$

$<span\; class="notranslate">\; +</span>\underset{{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; \&le;</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; N</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}{\mathrm{<span\; class="notranslate">\; \&gamma;</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; n</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; ,</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 5</span>}<span\; class="notranslate">\; )</span>$

In formula (5), n[g] represents Gaussian white noise. the

为基于第n个OFDM符号的频域判决反馈值 经过快速反傅立叶变换(inverse fast Fourier transform，以下简称：IFFT)变换得到的时域信号，即：  set up

is the frequency domain decision feedback value based on the nth OFDM symbol The time-domain signal obtained by inverse fast Fourier transform (hereinafter referred to as: IFFT) transformation, namely:

${\stackrel{<span\; class="notranslate">\; ^</span>}{\mathrm{<span\; class="notranslate">\; x</span>}}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; =</span>\underset{\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0</span>}}{\overset{\mathrm{<span\; class="notranslate">\; K</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\stackrel{<span\; class="notranslate">\; ^</span>}{\mathrm{<span\; class="notranslate">\; the\; s</span>}}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; ]</span>{\mathrm{<span\; class="notranslate">\; e</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="j"\; filenames="H2009102218700E00051.png"\; state="\{\{state\}\}">j</figure-callout></span>}\frac{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&pi;km</span>}}{\mathrm{<span\; class="notranslate">\; K</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 6</span>}<span\; class="notranslate">\; )</span>$

In formula (6), 0≦m<N, where N=K+N _G where K is the length of the FFT integration interval, and N _G is the length of the CP. Symbol synchronization is to determine the starting position of the FFT integration interval in 0≤m<N.

重构出当前OFDM符号所受到的IBI，公式(1)中的 

并从第n个OFDM符号的接收信号中减去所受到的IBI，得到：  First, use the decision feedback values of other OFDM symbols except the current OFDM symbol

Reconstruct the IBI received by the current OFDM symbol, in the formula (1)

and subtract the experienced IBI from the received signal of the nth OFDM symbol to obtain:

${\stackrel{<span\; class="notranslate">\; ^</span>}{\mathrm{<span\; class="notranslate">\; r</span>}}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; r</span>}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; n</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; h</span>}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; *</span>\underset{\mathrm{<span\; class="notranslate">\; l</span>}<span\; class="notranslate">\; \&NotEqual;</span>\mathrm{<span\; class="notranslate">\; no</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}{\stackrel{<span\; class="notranslate">\; ^</span>}{\mathrm{<span\; class="notranslate">\; x</span>}}}_{\mathrm{<span\; class="notranslate">\; l</span>}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; n</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; n</span>}<span\; class="notranslate">\; ]</span>$

$<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; r</span>}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; n</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; -</span>\underset{\mathrm{<span\; class="notranslate">\; i</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}\underset{\mathrm{<span\; class="notranslate">\; l</span>}<span\; class="notranslate">\; \&NotEqual;</span>\mathrm{<span\; class="notranslate">\; no</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}{\mathrm{<span\; class="notranslate">\; \&gamma;</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}{\stackrel{<span\; class="notranslate">\; ^</span>}{\mathrm{<span\; class="notranslate">\; x</span>}}}_{\mathrm{<span\; class="notranslate">\; l</span>}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; n</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; n</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 7</span>}<span\; class="notranslate">\; )</span>$

一般由接收机通过块判决反馈或迭代接收技术获得，一般情况下，当前OFDM符号所受到的IBI主要是其前、后OFDM符号导致的IBI，同时，当m＜0或 m＞N时，x_l[m]和 

均为0，因此式(7)可以简化为：  In formula (7), the range of m is -N ₁ ≤ m<N+N ₂ , where -N ₁ and N ₂ are the head path position and the end path position of the equivalent discrete channel respectively. It should be noted that the decision feedback value

Generally, it is obtained by the receiver through block decision feedback or iterative receiving technology. Generally, the IBI received by the current OFDM symbol is mainly the IBI caused by its previous and subsequent OFDM symbols. At the same time, when m<0 or m>N, x _l [m] and

are all 0, so formula (7) can be simplified as:

${\stackrel{<span\; class="notranslate">\; ^</span>}{\mathrm{<span\; class="notranslate">\; r</span>}}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; r</span>}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; n</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; -</span>\underset{{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; ></span>\mathrm{<span\; class="notranslate">\; m</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}{\mathrm{<span\; class="notranslate">\; \&gamma;</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}{\stackrel{<span\; class="notranslate">\; ^</span>}{\mathrm{<span\; class="notranslate">\; x</span>}}}_{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; -</span>\underset{{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; \&le;</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; N</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}{\mathrm{<span\; class="notranslate">\; \&gamma;</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}{\stackrel{<span\; class="notranslate">\; ^</span>}{\mathrm{<span\; class="notranslate">\; x</span>}}}_{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 8</span>}<span\; class="notranslate">\; )</span>$

Substituting formula (5) into formula (8), the received signal after IBI cancellation can be obtained:

${\stackrel{<span\; class="notranslate">\; ^</span>}{\mathrm{<span\; class="notranslate">\; r</span>}}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; =</span>\underset{\mathrm{<span\; class="notranslate">\; i</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}{\mathrm{<span\; class="notranslate">\; \&gamma;</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; +</span>\underset{{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; ></span>\mathrm{<span\; class="notranslate">\; m</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}{\mathrm{<span\; class="notranslate">\; \&gamma;</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; -</span>{\stackrel{<span\; class="notranslate">\; ^</span>}{\mathrm{<span\; class="notranslate">\; x</span>}}}_{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; )</span>$

$<span\; class="notranslate">\; +</span>\underset{{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; \&le;</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; N</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}{\mathrm{<span\; class="notranslate">\; \&gamma;</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; -</span>{\stackrel{<span\; class="notranslate">\; ^</span>}{\mathrm{<span\; class="notranslate">\; x</span>}}}_{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; n</span>}<span\; class="notranslate">\; ]</span>$

$<span\; class="notranslate">\; =</span>\underset{\mathrm{<span\; class="notranslate">\; i</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}{\mathrm{<span\; class="notranslate">\; \&gamma;</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; +</span>\underset{{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; ></span>\mathrm{<span\; class="notranslate">\; m</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}{\mathrm{<span\; class="notranslate">\; \&gamma;</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}{\mathrm{<span\; class="notranslate">\; e</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; ]</span>$

$<span\; class="notranslate">\; +</span>\underset{{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; \&le;</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; N</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}{\mathrm{<span\; class="notranslate">\; \&gamma;</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}{\mathrm{<span\; class="notranslate">\; e</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; n</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 9</span>}<span\; class="notranslate">\; )</span>$

In formula (9), e _l [m] represents the estimated variance of the mth decision feedback symbol for the lth OFDM symbol in the n OFDM symbols, which can be obtained by $e_l\left[m\right]=x_l\left[m\right]-{\hat{x}}_l\left[m\right]$ get. Specifically, the IBI experienced by the current OFDM symbol can be reconstructed by the inter-block interference elimination device, and IBI elimination can be performed by formula (7) or formula (9).

该判决值 

具体可以由接收机通过块判决反馈或迭代接收技术获得，重构出信号中缺失的CP部分，并补入如式(9)所示IBI消除后的接收信号中，进一步得到CP补偿后的接收信号，该接收信号为时域信号：  Furthermore, since the OFDM system guarantees the cyclic matrix characteristic of the channel matrix in the time domain through the function of the CP, it further ensures that there is no ICI in the frequency domain. Taking FIG. 1 as an example, since the CPs in signals 101 and 103 corresponding to paths 101 and 103 are incomplete, this leads to ICI in the frequency domain. The RISIC algorithm uses the decision feedback value of the current OFDM symbol itself

the judgment value

Specifically, it can be obtained by the receiver through block decision feedback or iterative reception technology, reconstruct the missing CP part in the signal, and fill it into the received signal after IBI cancellation as shown in equation (9), and further obtain the received signal after CP compensation signal, the received signal is a time-domain signal:

${\stackrel{<span\; class="notranslate">\; ^</span>}{\mathrm{<span\; class="notranslate">\; r</span>}}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; =</span>{\stackrel{<span\; class="notranslate">\; ^</span>}{\mathrm{<span\; class="notranslate">\; r</span>}}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; +</span>\underset{{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; ></span>\mathrm{<span\; class="notranslate">\; m</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}{\mathrm{<span\; class="notranslate">\; \&gamma;</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}{\stackrel{<span\; class="notranslate">\; ^</span>}{\mathrm{<span\; class="notranslate">\; x</span>}}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; K</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; +</span>\underset{{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; \&le;</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; N</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}{\mathrm{<span\; class="notranslate">\; \&gamma;</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}{\stackrel{<span\; class="notranslate">\; ^</span>}{\mathrm{<span\; class="notranslate">\; x</span>}}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; K</span>}<span\; class="notranslate">\; ]</span>$

$<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; r</span>}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; n</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; +</span>\underset{{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; ></span>\mathrm{<span\; class="notranslate">\; m</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}{\mathrm{<span\; class="notranslate">\; \&gamma;</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; (</span>{\stackrel{<span\; class="notranslate">\; ^</span>}{\mathrm{<span\; class="notranslate">\; x</span>}}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; K</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; -</span>{\stackrel{<span\; class="notranslate">\; ^</span>}{\mathrm{<span\; class="notranslate">\; x</span>}}}_{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; )</span>$

$<span\; class="notranslate">\; +</span>\underset{{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; \&le;</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; N</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}{\mathrm{<span\; class="notranslate">\; \&gamma;</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; (</span>{\stackrel{<span\; class="notranslate">\; ^</span>}{\mathrm{<span\; class="notranslate">\; x</span>}}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; K</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; -</span>{\stackrel{<span\; class="notranslate">\; ^</span>}{\mathrm{<span\; class="notranslate">\; x</span>}}}_{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; )</span><span\; class="notranslate">\; ,</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 10</span>}<span\; class="notranslate">\; )</span>$

In formula (10), the second and third items on the right side of the first equal sign are respectively the reconstruction items of the missing CP part at the left end and right end of the current OFDM symbol. The second item on the right side of the second equal sign is the IBI cancellation of the previous OFDM symbol from the current OFDM symbol and the reconstruction compensation for the missing CP part at the left end, and the third item represents the next OFDM symbol from the current OFDM symbol The IBI elimination and reconstruction compensation for the missing CP part at the right end. Among them, m _s ≤ m<m _s +K corresponds to the sign in the FFT integration window. Specifically, the CP reconstruction and compensation can be performed by the CP reconstruction device through formula (10), and the time-domain signal after the CP reconstruction and compensation is sent to the receiver.

After CP reconstruction and compensation of the received signal, the receiver can perform FFT on the CP compensated signal, convert the time domain signal into a frequency domain signal, and perform reception processing on the frequency domain signal, such as demodulation, decoding, etc. , generate the estimated variance for all OFDM symbol feedback for symbol synchronization, generate the decision value of the front and rear OFDM symbols of the current OFDM symbol for the reconstruction and elimination of IBI, and generate the decision value of the current OFDM symbol for CP reconstruction and compensation. the

Firstly, the influence of the feedback estimation variance for all OFDM symbols on the performance of IBI elimination, CP reconstruction and compensation in formula (10) is analyzed. introduce $e_l\left[m\right]=x_l\left[m\right]-{\hat{x}}_l\left[m\right]$ Represent the estimated variance of the mth decision feedback time-domain symbol of the lth OFDM symbol, then formula (10) can be expressed as:

$<span\; class="notranslate">\; +</span>\underset{{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; ></span>\mathrm{<span\; class="notranslate">\; m</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}{\mathrm{<span\; class="notranslate">\; \&gamma;</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; e</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; e</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; K</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; )</span>$

$<span\; class="notranslate">\; +</span>\underset{{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; \&le;</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; N</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}{\mathrm{<span\; class="notranslate">\; \&gamma;</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; e</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; e</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; K</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; n</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; ,</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 11</span>}<span\; class="notranslate">\; )</span>$

In formula (11), the first line on the right side of the equal sign represents the target signal part, that is, the nth symbol. Since there is no IBI in the target signal part, and the missing CP part is also reconstructed and compensated, so Satisfies the circular convolution property. The other parts, that is, the parts shown in the second row and the third row, are residual IBI and non-ideal CP reconstruction parts caused by errors or errors in decision feedback values. On the premise of ideal channel estimation, if the feedback decision value is completely accurate, the parts shown in the second row and the third row can be completely eliminated, that is to say, IBI and ICI can be ideally eliminated. But in practical applications, the estimated variance of the feedback symbols is unavoidable. The embodiments of the present invention can minimize the residual IBI and ICI energy and maximize the elimination of the IBI and ICI under the condition of a certain estimated variance of the feedback symbols. the

According to formula (11), the residual interference energy in each path signal can be obtained. For a path signal with a time delay of m _i samples, the residual interference energy is:

${\mathrm{<span\; class="notranslate">\; l</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\left\{\begin{array}{cc}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; G</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>& {\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; <</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; G</span>}}<span\; class="notranslate">\; ,</span>\\ \mathrm{<span\; class="notranslate">\; 0</span>}& {\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; G</span>}}<span\; class="notranslate">\; \&le;</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; \&le;</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}\\ <span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>& {\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; ></span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; .</span>\end{array}\right.<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 12</span>}<span\; class="notranslate">\; )</span>$

It can be seen from formula (12) that the residual interference energy of each path is a function of the symbol timing position m _s . Among them, σ _n ² is the estimated variance of the nth OFDM symbol, also called error, and so on.

Thus, the total residual interference energy of all paths in the current OFDM symbol can be obtained, as shown in formula (4). Since the estimated variances σ _n-1 ² , σ _n ² and σ _n+1 ² are determined by the detection performance of the receiver, and the channel factor γ _i obtains the power information of each path |γ _i | ² is determined by the performance of the channel estimation device, so , the total residual IBI and ICI energy is uniquely determined by the timing position m _s of the current OFDM symbol. The timing position m _s when the total residual interference energy ε(m _s ) is minimum is taken as the determined symbol timing $m_o=m_{i_o},$ That is, the residual interference energy ε(m _s ) after interference suppression can be minimized, that is, the residual interference energy ε(m _s ) after interference suppression can be reduced to the minimum. According to formula (4), it can be seen that m _s when minimizing the residual interference energy ε(m _s ), that is: $m_o=m_{i_o},$ is included in the set of delay positions {m _i } for each path.

Since the iteration needs to ensure convergence, usually, in the RISIC iterative processing method, the estimated variance of the current OFDM symbol block and the subsequent OFDM symbol block in this iteration is the same, while the symbol estimation variance of the previous OFDM symbol block is different, namely: ${\mathrm{\&sigma;}}_{\mathrm{no}-1}^2\&le;{\mathrm{\&sigma;}}_{\mathrm{no}}^2={\mathrm{\&sigma;}}_{\mathrm{no}+1}^2,$ definition ${\mathrm{\&sigma;}}_b^2={\mathrm{\&sigma;}}_{\mathrm{no}-1}^2,{\mathrm{\&sigma;}}_a^2={\mathrm{\&sigma;}}_{\mathrm{no}}^2={\mathrm{\&sigma;}}_{\mathrm{no}+1}^2,$ Formula (4) can be simplified as:

$\mathrm{<span\; class="notranslate">\; \&epsiv;</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 2</span>}{\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}_{\mathrm{<span\; class="notranslate">\; a</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}\underset{{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; <</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; a</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; G</span>}}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; G</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; )</span>{<span\; class="notranslate">\; |</span>{\mathrm{<span\; class="notranslate">\; \&gamma;</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; |</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}_{\mathrm{<span\; class="notranslate">\; a</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}_{\mathrm{<span\; class="notranslate">\; b</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>\underset{{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; ></span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; a</span>}}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; )</span>{<span\; class="notranslate">\; |</span>{\mathrm{<span\; class="notranslate">\; \&gamma;</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; |</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 13</span>}<span\; class="notranslate">\; )</span>$

At this time, the total residual interference energy of all paths in the current OFDM symbol can be obtained by formula (13). Then obtain the minimum interference energy in the total residual interference energy by i _o =argminε(m _i ), and obtain the starting position m _o corresponding to the minimum interference energy as the symbol timing value, and perform symbol synchronization on the received signal.

FIG. 4 is a schematic structural diagram of an embodiment of a symbol synchronization device according to the present invention. The symbol synchronization device of this embodiment can be used to implement the symbol synchronization methods of the above-mentioned embodiments of the present invention. As shown in FIG. 4 , the symbol synchronization device of this embodiment includes a first acquisition module 401 , a second acquisition module 402 , a third acquisition module 403 and a symbol synchronization module 404 . Among them, the first acquisition module 401 is used to receive the signal sent by the transmitting end, the signal is also called the received signal, acquire the position information and power information of each path in the current OFDM symbol in the received signal, and estimate the feedback for all OFDM symbols variance. The second acquisition module 402 is used to obtain the position information and power of each path acquired by the first acquisition module 401 according to the start position m _s of all FFT integration intervals in the preset start position set or the quantized start position set information, and the estimated variance fed back for all OFDM symbols, to obtain the total residual interference energy of all paths in the current OFDM symbol. The third obtaining module 403 is configured to obtain the starting position m _s corresponding to the minimum interference energy among the total residual interference energy obtained by the second obtaining module 402 . The symbol synchronization module 404 is configured to use the starting position m _s corresponding to the minimum interference energy acquired by the third acquisition module 403 as the symbol timing value to perform symbol synchronization on the received signal.

Specifically, for the processing process of each module in the symbol synchronization device in the embodiment of the present invention, reference may be made to the relevant description in the method embodiment. the

The symbol synchronization device of the embodiment of the present invention can use the starting position corresponding to the minimum interference energy in the total residual interference energy as the symbol timing value to perform symbol synchronization on the signal sent by the transmitting end, so that when the channel delay extension exceeds the CP length Under this condition, the residual interference energy after IBI elimination and ICI reconstruction compensation is reduced, so as to effectively realize the synchronization of OFDM symbols and improve the receiving performance of the receiver, for example: improve the bit error rate, symbol error rate or block error rate performance of data transmission wait. the

FIG. 5 is a schematic structural diagram of another embodiment of the symbol synchronization device according to the present invention. In this embodiment, the first obtaining module 401 includes a receiving unit 501 and a computing unit 502 . Among them, the receiving unit 501 is used to receive the signal sent by the sending end, that is: the received signal, and the position information m _i and channel factor γ _i of each path in the current OFDM symbol in the received signal, and the receiver feedbacks for all OFDM symbols The estimated variance σ _n ² of . The calculating unit 502 is configured to acquire power information |γ _i | ² of each path according to the channel factor γ _i received by the receiving unit 501 . Wherein, i represents the i-th path, which is an integer greater than zero, and σ _n ² is the estimated variance fed back for the n-th OFDM symbol. According to a specific embodiment, the position information m _i and the channel factor γ _i of each path in the current OFDM symbol in the received signal can be specifically obtained by a channel estimation device through channel estimation.

As an embodiment of the present invention, in the symbol synchronization device of the above-mentioned embodiment shown in FIG. 4 or FIG. 5 , the second acquisition module 402 is specifically based on the position information m _i and power information |γ _i | ² of each path, and for The estimated variance σ _n ² of all OFDM symbol feedback, based on $\mathrm{\&epsiv;}\left(m_{\mathrm{the\; s}}\right)=\underset{i}{\mathrm{\&Sigma;}}{l}_i\left(m_{\mathrm{the\; s}}\right){\left|{\mathrm{\&gamma;}}_i\right|}^2$ Or the above formula (4) obtains the total residual interference energy of all paths in the current OFDM symbol.

As another embodiment of the present invention, in the symbol synchronization device of the above-mentioned embodiment shown in FIG. 4 or FIG. 5 , the third acquisition module 403 specifically acquires the minimum interference energy in the total residual interference energy, and calculates the minimum interference energy according to i _o =argminε( m _i ) Obtain the radial position m _o corresponding to the minimum interference energy, where, $m_o=m_{i_o},$ argminε(m _i ) represents a parameter that minimizes ε(m _i ).

As yet another embodiment of the present invention, in the symbol synchronization device of the embodiment shown in FIG. 4 or FIG. 5 above, ${\mathrm{\&sigma;}}_{\mathrm{no}-1}^2\&le;{\mathrm{\&sigma;}}_{\mathrm{no}}^2={\mathrm{\&sigma;}}_{\mathrm{no}+1}^2$ When , the second obtaining module 402 obtains the total residual interference energy of all paths in the current OFDM symbol based on the above formula (13).

Fig. 6 is a schematic structural diagram of an embodiment of the receiving processing system of the present invention. As shown in FIG. 6 , the receiving processing system of this embodiment includes a channel estimation device 601 , a symbol synchronization device 602 , an inter-block interference elimination device 603 , a cyclic prefix reconstruction device 604 and a receiver 605 . Wherein, the channel estimation device 601 is used to perform channel estimation using signals received by the receiving end to obtain time-domain channel information of each path, and the time-domain channel information includes position information and channel factors of each path. The symbol synchronization device 602 is used to receive the signal sent by the transmitting end, obtain the position information and power information of each path in the current OFDM symbol according to the time domain channel information of each path, and receive the estimation fed back by the receiver 605 for all OFDM symbols Variance, according to the position information and power information of each path, and the estimated variance for all OFDM symbol feedback, for the start position m _s of all FFT integration intervals in the preset start position set or the quantized start position set, Obtain the total residual interference energy of all paths in the current OFDM symbol, and obtain the starting position corresponding to the minimum interference energy in the total residual interference energy, and use the starting position corresponding to the minimum interference energy as the symbol timing value to send the The signal is symbol-synchronized. The inter-block interference elimination device 603 is used to perform symbol synchronization by the symbol synchronization device 602 according to the time-domain channel information of each path sent by the channel estimation device 601 and the decision value of the receiver 605 for the previous and subsequent OFDM symbols of the current OFDM symbol. The synchronized received signal is subjected to IBI cancellation. The cyclic prefix reconstruction unit 604 is used to perform IBI cancellation on the signal after the inter-block interference cancellation unit 603 according to the time-domain channel information of each path sent by the channel estimation unit 601 and the decision value for the current OFDM symbol sent by the receiver 605 Perform CP reconstruction and compensation. Among them, the received signals processed by the channel estimation device 601, the symbol synchronization device 602, the inter-block interference elimination device 603 and the cyclic prefix reconstruction device 604 are all time-domain signals, therefore, after the CP reconstruction and compensation by the cyclic prefix reconstruction device 604 The signal is also a time-domain signal. The receiver 605 is used to perform FFT on the time-domain signal sent by the cyclic prefix reconstruction device 604, transform the time-domain signal after CP reconstruction and compensation into a frequency-domain signal, and perform receiving processing on the frequency-domain signal, for example: modulation, decoding, etc., generate the estimated variance for all OFDM symbol feedback and send it to the symbol synchronization device 602 for symbol synchronization, generate the decision value of the front and rear OFDM symbols of the current OFDM symbol and send it to the inter-block interference elimination device 603 It is used for IBI reconstruction and elimination, and the decision value of the current OFDM symbol is generated and sent to the cyclic prefix reconstruction device 604 for CP reconstruction and compensation. Specifically, the symbol synchronization device 602 may be implemented by the symbol synchronization device in the embodiment shown in FIG. 4 or FIG. 5 .

In the receiving processing system of the embodiment of the present invention, the symbol synchronization device can use the starting position corresponding to the minimum interference energy in the total residual interference energy as the symbol timing value to perform symbol synchronization on the signal sent by the transmitting end, so that when the channel delay extends beyond In the case of CP length, the residual interference energy after IBI elimination and ICI reconstruction compensation is reduced, so as to effectively realize the synchronization of OFDM symbols and improve the receiving performance of the receiver, for example: improve the bit error rate of data transmission, symbol error rate or Block error rate performance, etc. the

As shown in FIG. 7 , it is a schematic structural diagram of another embodiment of the receiving processing system of the present invention. In this embodiment, the symbol synchronization device 602 is realized by the symbol synchronization device of the embodiment shown in FIG. 4 . Wherein, the first obtaining module 401 is used to receive the signal sent by the transmitting end, according to the time domain channel information of each path sent by the channel estimation device 601, obtain the position information and power information of each path in the current OFDM symbol, and receive 605 Feedback estimated variances for all OFDM symbols. The second acquisition module 402 is used to obtain the position information and power information of each path acquired by the first acquisition module 401 according to the start position m _s of all FFT integration intervals in the preset start position set or the quantized start position set , and the estimated variance fed back by the receiver 605 for all OFDM symbols, to obtain the total residual interference energy of all paths in the current OFDM symbol. The third obtaining module 403 is configured to obtain the starting position corresponding to the minimum interference energy among the total residual interference energy obtained by the second obtaining module 402 . The symbol synchronization module 404 is configured to use the path position corresponding to the minimum interference energy obtained by the third obtaining module 403 as a symbol timing value to perform symbol synchronization on the signal sent by the transmitting end.

As a further embodiment of the present invention, the channel estimation device 601 and the symbol synchronization device 602 may be set integrally. the

Those of ordinary skill in the art can understand that all or part of the steps for realizing the above-mentioned method embodiments can be completed by hardware related to program instructions, and the aforementioned program can be stored in a computer-readable storage medium. When the program is executed, the It includes the steps of the above method embodiments; and the aforementioned storage medium includes: ROM, RAM, magnetic disk or optical disk and other various media that can store program codes. the

In the embodiment of the present invention, the starting position corresponding to the minimum interference energy in the total residual interference energy is used as the symbol timing value to perform symbol synchronization on the signal sent by the transmitting end, which can reduce IBI elimination when the channel delay extension exceeds the CP length and ICI to reconstruct the compensated residual interference energy, thereby effectively realizing the synchronization of OFDM symbols and improving the receiving performance of the receiver. the

The embodiment of the present invention tested respectively the IBI and IBI in the OFDM system based on the Worldwide Interoperability for Microwave Access (Worldwide Interoperability for Microwave Access, hereinafter referred to as: WIMAX) standard when using the prior art and the embodiment of the present invention under the same conditions. The ICI suppression performance is used to more clearly illustrate the beneficial technical effects of the embodiments of the present invention. The subcarrier spacing of the OFDM system is 10.94kHz, the total bandwidth is 10MHz, the number of subcarriers in each OFDM symbol block is 914, and the CP length is 1/8 symbol period length. The power of the path channel is the same, the delay extension length is 17.8 microseconds, the modulation method of sending OFDM symbols is 4 quadrature amplitude modulation (Quadrature Amplitude Modulation, hereinafter referred to as: QAM), and the channel code is (50, 33) Solomon code (Reed- Solomon codes, hereinafter referred to as: RS). The test results are shown in Figure 8 and Figure 9. Fig. 8 is a schematic diagram of a symbol error rate performance improvement after adopting the embodiment of the symbol synchronization method of the present invention. FIG. 9 is a schematic diagram of a block error rate performance improvement after adopting an embodiment of the symbol synchronization method of the present invention. In Fig. 8 and Fig. 9, "optimization method for one iteration" means the RISIC iterative performance once tested by using the symbol synchronization method of the embodiment of the present invention; "optimization method for two iterations" means using the symbol synchronization method of the embodiment of the present invention The tested RISIC iterative secondary performance; "the original RISIC method of one iteration" means the RISIC iterative performance of the prior art symbol synchronization method; "the RISIC method of ideal decision feedback" means the RISIC performance when the decision feedback is assumed to be completely correct. the

Usually, 1% is selected as the working point of the symbol error rate. It can be seen from Figure 8 that under the same SNR condition, the symbol error rate of the "optimization method with one iteration" and the "optimization method with two iterations" are lower than the "original RISIC method with one iteration", therefore, they have relatively Good RISIC performance, and, as the signal-to-noise ratio increases, the RISIC performance advantages brought by the "iterative optimization method" and "iterative second optimization method" are more obvious than the "original RISIC method of iterative once". At the 1% working point, the RISIC performance of the "iterative optimization method" and "iterative quadratic optimization method" is close to the performance upper bound of the "ideal decision feedback RISIC method". the

Normally, 10% is selected as the working point of the block error rate. It can be seen from Fig. 9 that under the same SNR condition, the block error rate of the "optimization method with one iteration" and the "optimization method with two iterations" are lower than the "original RISIC method with one iteration", therefore, they have relatively Good RISIC performance, and, as the signal-to-noise ratio increases, the RISIC performance advantages brought by the "iterative optimization method" and "iterative second optimization method" are more obvious than the "original RISIC method of iterative once". At the 10% working point, the RISIC performance of the "optimization method with one iteration" and "the optimization method with two iterations" approaches the performance upper bound of "the RISIC method with ideal decision feedback". the

It can be seen from Fig. 8 and Fig. 9 that after adopting the symbol synchronization method of the embodiment of the present invention, in the scenario where the channel delay spread is greater than CP, the RISIC performance of the original typical IBI/ICI algorithm is greatly improved, thereby improving the corresponding reception machine performance and robustness. the

Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present invention, rather than limiting the understanding of the present invention. Although the present invention has been described in detail with reference to the above-mentioned preferred embodiments, those skilled in the art should understand that: it can still modify or replace the technical solution of the present invention, and such modification or replacement does not depart from the technology of the present invention. The spirit and scope of the programme. the

Claims (13)

1. A symbol synchronization method, characterized in that, comprising: receiving the signal sent by the transmitting end, obtaining the position information and power information of each path in the current OFDM symbol in the signal, and obtaining the estimated variance fed back for all OFDM symbols; According to the preset start position set or the start position of all fast Fourier transform integration intervals in the quantized start position set, the obtained position information and power information of each path and the estimated variance for all OFDM symbol feedback, Obtain the total residual interference energy of all paths in the current OFDM symbol; Obtain the starting position corresponding to the minimum interference energy in the total residual interference energy; The starting position corresponding to the minimum interference energy is used as a symbol timing value to perform symbol synchronization on the signal sent by the transmitting end. 2. The method according to claim 1, wherein obtaining position information and power information of each path in the current OFDM symbol in the signal comprises: Obtain the position information m _i and channel factor γ _i of each path in the current OFDM symbol through channel estimation, and obtain the power information |γ _i | ² of each path according to the channel factor γ _i , where i represents the i-th path, which is An integer greater than zero. 3. The method according to claim 1, wherein said acquisition comprises: Receive the estimated variance fed back by the receiver for all OFDM symbols. 4. The method according to claim 2, wherein, the total residual interference energy of all paths in the current OFDM symbol is obtained in the following manner:

Among them, ε(m _s ) is the total residual interference energy of all paths in the current OFDM symbol, m _s is the symbol timing position of the nth OFDM symbol, l _i (m _s ) indicates that when the symbol timing position is m _s The interference energy of path i, |γ _i | ² is the power information of each path. 5. The method according to claim 2, wherein, the total residual interference energy of all paths in the current OFDM symbol is obtained in the following manner:

Wherein, ε(m _s ) is the total residual interference energy of all paths in the current OFDM symbol, is the estimated variance fed back for the n-th OFDM symbol, N _G is the CP length of the cyclic prefix, m _s is the symbol timing position of the n-th OFDM symbol, |γ _i | ² is the power information of each path. 6. The method according to claim 4 or 5, wherein said obtaining the initial position corresponding to the minimum interference energy in the total residual interference energy comprises: Obtain the minimum interference energy in the total residual interference energy, and obtain the starting position m _o corresponding to the minimum interference energy according to i _o =argminε(m _i ), where,

argminε(m _i ) represents a parameter that minimizes ε(m _i ). 7. The method according to claim 5, wherein when

When , the total residual interference energy of all paths in the current OFDM symbol is obtained in the following manner:

in,

8. A symbol synchronization device, comprising: The first obtaining module is used to receive the signal sent by the transmitting end, obtain the position information and power information of each path in the current OFDM symbol in the signal, and the estimated variance for all OFDM symbol feedback; The second acquisition module is configured to use the preset start position set or the start position of all integration intervals in the quantized start position set, the position information and power information of each path acquired by the first acquisition module, and Obtaining the total residual interference energy of all paths in the current OFDM symbol for the estimated variance fed back by all OFDM symbols; The third acquisition module is used to acquire the starting position corresponding to the minimum interference energy in the total residual interference energy; A symbol synchronization module, configured to use the starting position corresponding to the minimum interference energy as a symbol timing value to perform symbol synchronization on the signal sent by the transmitting end. 9. The device according to claim 8, wherein the first acquiring module comprises: The receiving unit is used to receive the signal sent by the transmitting end, the position information m _i and the channel factor γ _i of each path in the current OFDM symbol in the signal obtained through channel estimation, and the estimated variance fed back for all OFDM symbols; A calculation unit, configured to acquire power information |γ _i | ² of each path according to the channel factor γ _i ; Wherein, i represents the i-th path, which is an integer greater than zero, and σ _n ² is the estimated variance fed back for the n-th OFDM symbol. 10. The device according to claim 9, wherein the second acquisition module is based on the position information m _i and power information |γ _i | ² of each path acquired by the first acquisition module, and for all OFDM The estimated variance σ _n ² of symbol feedback is obtained by the following method to obtain the total residual interference energy of all paths in the current OFDM symbol:

or Among them, ε(m _s ) is the total residual interference energy of all paths in the current OFDM symbol, m _s is the symbol timing position of the nth OFDM symbol, l _i (m _s ) indicates that when the symbol timing position is m _s The interference energy of the i path, N _G is the length of the cyclic prefix CP. 11. The device according to claim 10, wherein the third obtaining module obtains the minimum interference energy in the total residual interference energy, and obtains the starting point corresponding to the minimum interference energy according to i _o =argminε(m _i ). initial position m _o , where,

argminε(m _i ) represents a parameter that minimizes ε(m _i ). 12. The device according to claim 10 or 11, characterized in that when

, the second obtaining module obtains the total residual interference energy of all paths in the current OFDM symbol in the following manner:

in,

13. A reception processing system, characterized by comprising: a channel estimation device, an inter-block interference elimination device, a cyclic prefix reconstruction device, a receiver, and a symbol synchronization device according to any one of claims 8 to 12, wherein , The channel estimation device is used to perform channel estimation using signals received by the receiving end to obtain time-domain channel information of each path, and the time-domain channel information includes position information and channel factors of each path; The inter-block interference elimination device is configured to, according to the time-domain channel information of each path and the decision value of the receiver for the previous OFDM symbol and the subsequent OFDM symbol of the current Orthogonal Frequency Division Multiplexing OFDM symbol, to the The symbol synchronization device performs inter-block interference IBI elimination on the signal after symbol synchronization; The cyclic prefix reconstruction device is configured to perform CP reconstruction and compensation on the signal after IBI cancellation according to the time-domain channel information of each path and the decision value sent by the receiver for the current OFDM symbol; The receiver is used to transform the time-domain signal after CP reconstruction and compensation into the frequency domain and perform receiving processing, generate the estimated variance for all OFDM symbol feedback and send it to the symbol synchronization device, and generate the current OFDM The judgment values of the previous and subsequent OFDM symbols of the symbol are sent to the inter-block interference elimination device, and the judgment value of the current OFDM symbol is generated and sent to the cyclic prefix reconstruction device. the

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