Space domain filtering method and device for multiple-input multiple-output system in rayleigh channel

Abstract

This invention discloses a spatial filtering method and apparatus for a multiple-input multiple-output (MIMO) system in a Rayleigh channel. The method includes: obtaining a first weighting coefficient matrix based on a minimum mean square error (MSE) criterion and training sequences from the received signals of each antenna; and weighting and combining the received signals based on the first weighting coefficient matrix to perform spatial filtering on each received signal. This invention provides a spatial filtering anti-interference scheme for MIMO systems in a Rayleigh channel. By using a spatial filtering scheme based on space-time block codes to obtain a weighting matrix using training sequences and a minimum mean square error criterion, and by weighted summation of signals between receiving antennas to cancel interference, it achieves superior anti-interference performance for the Rayleigh channel MIMO system. Furthermore, through data filtering and synchronization strategies, it improves and ensures the anti-interference capability of the entire link.

Description

Technical Field

[0001] This invention relates to the field of wireless communication technology, and in particular to a spatial filtering method and apparatus for a multiple-input multiple-output system in a Rayleigh channel. Background Technology

[0002] In wireless communication within complex electromagnetic environments, numerous unintentional or intentional interference signals exist, severely impacting normal communication quality. Therefore, interference mitigation remains a significant technical challenge in wireless communication in complex electromagnetic environments. When faced with constant, full-band suppressive interference, traditional anti-interference strategies such as direct-sequence spread spectrum, frequency hopping, time hopping, and frequency selection are insufficient. In such cases, spatial resources can be utilized for interference mitigation.

[0003] Current practical anti-interference methods based on spatial filtering, which do not rely on receiver feedback of Channel State Information (CSI) under interference conditions, are essentially receiver beamforming techniques based on Single-Input Multiple-Output (SIMO) systems. Depending on whether the receiver requires a training sequence, they can be divided into coherent and incoherent implementations. Coherent methods require a training sequence during design; a representative algorithm is spatial Wiener filtering. Coherent methods offer good interference suppression but require mastery of the underlying technology. Incoherent methods do not require a training sequence during design; a representative algorithm is the power inversion algorithm. Incoherent methods offer good suppression of high-power interference but are prone to miscancellation of useful signals when facing low-power interference.

[0004] Current research on spatial anti-jamming technology mainly focuses on SIMO systems in Gaussian channels, while practical applications increasingly utilize Multiple-Input Multiple-Output (MIMO) systems in Rayleigh channels. Especially when the jammer simultaneously transmits multiple jamming signals, existing spatial anti-jamming technologies struggle to effectively achieve their anti-jamming objectives.

[0005] The information disclosed in this background section is intended only to enhance the understanding of the overall background of the invention and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0006] The purpose of this invention is to provide a spatial filtering method and apparatus for a multiple-input multiple-output system in a Rayleigh channel, which can effectively achieve anti-interference.

[0007] To achieve the above objectives, this invention provides a spatial filtering method for a multiple-input multiple-output system in a Rayleigh channel, comprising:

[0008] Based on the minimum mean square error criterion, the first weighting coefficient matrix is ​​obtained according to the training sequence in the received signals of each antenna;

[0009] Based on the first weighting coefficient matrix, the received signals are weighted and combined to perform spatial filtering on each received signal.

[0010] In one embodiment of the present invention, before performing weighted merging of the received signals based on the first weight coefficient matrix to perform spatial filtering on the received signals, the method further includes:

[0011] The second weighting coefficient matrix is ​​obtained based on the synchronization sequence in each of the received signals;

[0012] Based on the second weighting coefficient matrix, the received signals are weighted and combined to perform spatial filtering on each received signal and obtain an estimated signal.

[0013] Synchronization of each received signal is performed based on the estimated signal.

[0014] In one embodiment of the present invention, obtaining the first weight coefficient matrix based on the training sequence in the received signals of each antenna according to the minimum mean square error criterion includes:

[0015] Based on the minimum mean square error criterion, the cross-correlation matrix between each received signal and each transmitted signal is obtained according to the training sequence.

[0016] Based on the cross-correlation matrix, the first weight coefficient matrix is ​​obtained.

[0017] In one embodiment of the present invention, obtaining the second weighting coefficient matrix based on the synchronization sequence in each of the received signals includes:

[0018] Based on the synchronization sequence, the first arithmetic mean of the autocorrelation matrix sequence of each of the received signals and the second arithmetic mean of the cross-correlation matrix sequence of each of the received signals and each of the transmitted signals are obtained.

[0019] The second weight coefficient matrix is ​​obtained based on the first arithmetic mean and the second arithmetic mean.

[0020] In one embodiment of the present invention, before synchronizing the received signals based on the estimated signal, the method further includes:

[0021] Perform space-time block code mapping on the symbol vector to obtain a three-dimensional matrix sequence;

[0022] Based on the three-dimensional matrix sequence and the number of transmitting antennas, a metric value is obtained; the metric value is used to determine whether synchronization is successful.

[0023] In one embodiment of the present invention, the transmitted signal is encapsulated based on the Link-16 data link standard, uses Turbo coding and has a code rate lower than the standard code rate of Turbo coding, and the training sequence uses coherence.

[0024] In one embodiment of the present invention, a spatial filtering device for a multiple-input multiple-output system in a Rayleigh channel is also provided, comprising:

[0025] The acquisition module is used to obtain the first weight coefficient matrix based on the training sequence in the received signals of each antenna according to the minimum mean square error criterion.

[0026] The filtering module is used to perform weighted merging of each of the received signals based on the first weight coefficient matrix, so as to perform spatial filtering on each of the received signals.

[0027] In one embodiment of the present invention, an electronic device includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, it implements the steps of the spatial filtering method for a multiple-input multiple-output system in a Rayleigh channel as described above.

[0028] In one embodiment of the present invention, a non-transitory computer-readable storage medium is provided, on which a computer program is stored, which, when executed by a processor, implements the steps of the spatial filtering method for a multiple-input multiple-output system in a Rayleigh channel as described above.

[0029] In one embodiment of the present invention, a computer program product includes a computer program that, when executed by a processor, implements the steps of the spatial filtering method for a multiple-input multiple-output system in a Rayleigh channel as described above.

[0030] Compared with existing technologies, the spatial filtering method, apparatus, electronic device, and storage medium for a Rayleigh channel multiple-input multiple-output (MIMO) system according to the present invention offer the following advantages: By employing a spatial filtering anti-interference scheme for MIMO systems based on space-time block codes, and utilizing a weighting matrix obtained from training sequences based on the minimum mean square error criterion, interference can be canceled through weighted summation of signals between receiving antennas. This achieves superior anti-interference performance for the Rayleigh channel MIMO system. Furthermore, through data filtering and synchronization strategies, the anti-interference capability of the entire link can be improved and guaranteed. Attached Figure Description

[0031] Figure 1 This is a schematic flowchart of a spatial filtering method for a multiple-input multiple-output system in a Rayleigh channel according to an embodiment of the present invention.

[0032] Figure 2This is a schematic diagram of the wireless transmission structure of a MIMO system with interference according to an embodiment of the present invention.

[0033] Figure 3 This is a schematic diagram illustrating the principle of STBC-based spatial filtering synchronization in a spatial filtering method for a multiple-input multiple-output system in a Rayleigh channel according to an embodiment of the present invention.

[0034] Figure 4 This is one of the schematic diagrams of an improved time slot structure used in a spatial filtering method for a multiple-input multiple-output system in a Rayleigh channel according to an embodiment of the present invention;

[0035] Figure 5 This is a second schematic diagram of an improved time slot structure used in a spatial filtering method for a multiple-input multiple-output system in a Rayleigh channel according to an embodiment of the present invention.

[0036] Figure 6 This is one of the schematic diagrams of an improved hop structure in an improved time slot structure used in a spatial filtering method for a multiple-input multiple-output system in a Rayleigh channel according to an embodiment of the present invention;

[0037] Figure 7 This is a second schematic diagram of the improved hop structure in the improved time slot structure used in the spatial filtering method of a multiple-input multiple-output system in a Rayleigh channel according to an embodiment of the present invention.

[0038] Figure 8 This is a schematic diagram illustrating the synchronization performance of the conventional maximum ratio combining technique in related technologies under interference-free conditions.

[0039] Figure 9 This is a schematic diagram illustrating the synchronization performance of a spatial filtering method for a multiple-input multiple-output system in a Rayleigh channel according to an embodiment of the present invention, using a synchronization segment under interference-free conditions.

[0040] Figure 10 This is a schematic diagram illustrating the synchronization performance of the conventional Maximum Ratio Combining (MBR) technique in related technologies under interference conditions.

[0041] Figure 11 This is a schematic diagram illustrating the synchronization performance of a spatial filtering method for a multiple-input multiple-output system in a Rayleigh channel according to an embodiment of the present invention, using a synchronization segment under interference conditions.

[0042] Figure 12 This is a schematic diagram of the bit error rate of a spatial filtering method for a multiple-input multiple-output system in a Rayleigh channel according to an embodiment of the present invention under interference-free conditions.

[0043] Figure 13 This is a schematic diagram of the block error rate of a spatial filtering method for a multiple-input multiple-output system in a Rayleigh channel according to an embodiment of the present invention under interference-free conditions.

[0044] Figure 14 This is a schematic diagram of the bit error rate of a spatial filtering method for a multiple-input multiple-output system in a Rayleigh channel according to an embodiment of the present invention under interference conditions.

[0045] Figure 15 This is a schematic diagram of the block error rate of a spatial filtering method for a multiple-input multiple-output system in a Rayleigh channel according to an embodiment of the present invention under interference conditions.

[0046] Figure 16 This is a schematic diagram of the spatial filtering device of a multiple-input multiple-output system in a Rayleigh channel according to an embodiment of the present invention.

[0047] Figure 17 This is a schematic diagram of the structure of an electronic device according to an embodiment of the present invention. Detailed Implementation

[0048] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0049] Unless otherwise expressly stated, throughout the specification and claims, the term "comprising" or its variations such as "including" or "comprises" shall be understood to include the stated elements or components without excluding other elements or other components.

[0050] like Figures 1 to 17 As shown, the spatial filtering method, apparatus, electronic device, and storage medium for a multiple-input multiple-output system in a Rayleigh channel according to a preferred embodiment of the present invention can be implemented in the following ways.

[0051] Figure 1 This is a schematic flowchart of a spatial filtering method for a multiple-input multiple-output system in a Rayleigh channel according to an embodiment of the present invention. Figure 1 As shown, the method may include the following steps:

[0052] Step 101: Based on the minimum mean square error criterion, obtain the first weight coefficient matrix according to the training sequence in the received signal of each antenna;

[0053] Step 102: Based on the first weighting coefficient matrix, weighted merge of each received signal is performed to perform spatial filtering on each received signal.

[0054] It should be noted that the embodiments of the present invention are applicable to MIMO systems subject to interference, and can perform more effective anti-interference.

[0055] Figure 2 This is a schematic diagram of the wireless transmission structure of a MIMO system with interference. Let the number of antennas for the transmitter, receiver, and jammer be respectively... , and The receiver's average signal-to-noise ratio is The average noise-to-interference ratio is Let the average interference-to-signal ratio be... Then there is Let the symbol period of space-time coding be... ,but Transmit signal , Interference signal , Additive noise and Received signal The relationship between them is

[0056] .

[0057] in, matrix This represents the channel fading coefficient between the transmitter and receiver. matrix This represents the channel fading coefficient between the jammer and the receiver. , and The components all follow a complex normal distribution. .

[0058] Because the fading coefficient of a MIMO channel is highly random, and the directions of the transmitter and jammer are independent of the fading coefficient, the fading coefficient... and The probability of the same direction is extremely low, so the anti-interference strategy is unrelated to the actual direction.

[0059] This invention proposes an anti-interference scheme for spatial filtering in MIMO systems based on Space-Time Block Code (STBC). It utilizes training sequences to calculate a weight matrix based on the minimum mean square error criterion, and then cancels out interference by weighted summation of signals between receiving antennas. This invention also proposes data filtering and synchronization strategies to ensure anti-interference capability across the entire link.

[0060] Space-Time Block Code (STBC) is a coding technique used in multi-antenna communication systems. In flat-fading channels, by designing the transmission method of signals in the spatial and temporal dimensions, the original data is mapped to a space-time matrix to obtain spatial diversity gain and improve the reliability of wireless communication.

[0061] Based on the orthogonality of signals between transmitting antennas, commonly used STBCs can be divided into orthogonal and quasi-orthogonal types. Among them, OSTBC (orthogonal STBC) has the advantages of high diversity gain and low detection complexity, but there are fewer types, and complex signals are difficult to achieve full rate. QSTBC (quasi-orthogonal STBC) has more types and higher rates, but its detection complexity is higher. Nevertheless, OSTBC is still the main type used in practical applications.

[0062] For simplicity, only full-rate real signals are considered here. The OSTBC coding matrices are as follows: [List of matrices would be inserted here] when the number of transmit antennas is 2, 4, and 8.

[0063] , and .

[0064] Let the data rate be Bits / symbols, the total number of available signal matrices is In space-time coding, an indirect method of baseband modulation followed by space-time coding can be used, or a direct method of mapping baseband symbols directly to a space-time code matrix can be used. In the direct method, each baseband symbol corresponds one-to-one with the first column of each coding matrix, and thus one-to-one with each coding matrix. Corresponding to the direct method, the typical maximum likelihood detection criterion at the receiver is...

[0065] .

[0066] For OSTBC, a simplified detection method can be readily obtained.

[0067] It should be noted that this invention proposes an anti-interference scheme for spatial filtering in MIMO systems based on Space-Time Block Code (STBC). The scheme utilizes training sequences to calculate a weight matrix based on the minimum mean square error criterion, and cancels out interference by weighted summation of signals between receiving antennas. This invention also proposes data filtering and synchronization strategies to ensure anti-interference capability across the entire link.

[0068] In some feasible implementations, based on the minimum mean square error criterion, a first weighting coefficient matrix is ​​obtained according to the training sequence in the received signals of each antenna, including:

[0069] Based on the minimum mean square error criterion, the cross-correlation matrix between each received signal and each transmitted signal is obtained according to the training sequence.

[0070] The first weight coefficient matrix is ​​obtained based on the cross-correlation matrix.

[0071] Specifically, the spatial filtering described above refers to spatial filtering of the data segment. (Reference) Figure 3 The data segment includes the training sequence and data symbols.

[0072] Based on the minimum mean square error criterion, let the order be... The first weight coefficient matrix is

[0073] .

[0074] Define the following variables

[0075] .

[0076] in, Let F be the norm of the matrix. Variable The mathematical expectation is

[0077] .

[0078] The autocorrelation matrix of each received signal is as follows: The cross-correlation matrix between each transmitted signal and each received signal is as follows: .

[0079] For the first weight coefficient matrix Find the partial derivative and set it to be... A matrix consisting entirely of zeros has

[0080] .

[0081] Therefore, there are

[0082] .

[0083] Therefore, there is an optimal weight matrix.

[0084] .

[0085] In applications, time averaging can replace statistical averaging, i.e., the weight matrix can be estimated from known training sequences.

[0086] In some feasible implementations, before weighting and combining the received signals based on the first weighting coefficient matrix to perform spatial filtering on the received signals, the method further includes:

[0087] The second weighting coefficient matrix is ​​obtained based on the synchronization sequence in each received signal;

[0088] Based on the second weighting coefficient matrix, the received signals are weighted and combined to perform spatial filtering on each received signal and obtain the estimated signal.

[0089] Synchronization of each received signal is performed based on the estimated signal.

[0090] Specifically, spatial filtering can also be performed during the synchronization segment. The synchronization segment includes the synchronization sequence, and performing spatial filtering during the synchronization segment can improve the signal synchronization performance.

[0091] In some feasible implementations, the second weighting coefficient matrix is ​​obtained based on the synchronization sequence in each received signal, including:

[0092] Based on the synchronization sequence, the first arithmetic mean of the autocorrelation matrix sequence of each received signal and the second arithmetic mean of the cross-correlation matrix sequence of each received signal and each transmitted signal are obtained.

[0093] The second weight coefficient matrix is ​​obtained based on the first and second arithmetic means.

[0094] Specifically, the above method can achieve anti-interference of synchronization segments based on STBC matrix sequences.

[0095] Set a window with a length equal to the length of the synchronization sequence symbol, capture the received signal within the window, and convert it into a three-dimensional matrix. Each of its submatrices is OK Calculate the arithmetic mean of the autocorrelation matrix sequence of the received signal (which can be denoted as the first arithmetic mean).

[0096] .

[0097] Calculate the arithmetic mean (which can be denoted as the second arithmetic mean) of the cross-correlation matrix sequences of the received and transmitted signals.

[0098] .

[0099] Then calculate the second weight coefficient matrix.

[0100] .

[0101] The received signal is weighted and combined using the obtained second weighting coefficient matrix to obtain the estimated signal after filtering out interference.

[0102] .

[0103] Will Synchronization matrix sequence with local Perform related calculations When its value exceeds the predetermined threshold, synchronization is considered successful.

[0104] In some feasible implementations, the method further includes, prior to synchronizing the received signals based on the estimated signals:

[0105] Perform space-time block code mapping on the symbol vector to obtain a three-dimensional matrix sequence;

[0106] Based on the three-dimensional matrix sequence and the number of transmitting antennas, a metric is obtained; the metric is used to determine whether synchronization is successful.

[0107] Specifically, the metric can be the aforementioned predetermined threshold.

[0108] The design of synchronization signals based on STBC can employ a synchronization sequence search algorithm based on STBC signals. When searching for a synchronization sequence based on STBC signals, the symbol rate parameter is first initialized according to requirements. Symbol period of space-time coding Number of transmitting antennas Find .make For containing A constellation set of STBC signal matrices, the length of which is... Then the baseband symbol length is . for A matrix consisting entirely of zeros. Let... And order .

[0109] Let the symbol vector be All of its components are integers, and in The values ​​between them follow a random distribution. Performing an STBC mapping on the symbol vector yields a quantity of... A three-dimensional matrix sequence of UST signals (Unitary Space-Time Modulation signals). , of which each All Matrix. Three-dimensional matrix sequence By concatenating adjacent matrices, we obtain Two-dimensional matrix . Matrix One in series at the front and one at the back All-zero matrix , to obtain the matrix For each , matrix The Arrive at the row marker as Calculate the metric value , and mark .make That is, remove the main peak value and then take the maximum value of the remaining metrics. .if If so, continue the loop search; if Then Value update The value is used as the new initial metric. The above process is repeated until it is difficult to find a new metric, at which point the loop ends.

[0110] In some feasible implementations, the transmitted signal is encapsulated based on the Link-16 data link standard, uses Turbo coding with a code rate lower than the standard code rate of Turbo coding, and the training sequence uses coherence.

[0111] Specifically, the embodiments of the present invention employ an improved time slot based on the STBC-based Link-16 data link.

[0112] In the Link-16 data link standard, the total number of available frequency points is 51, the symbol rate is 5 Msps, and the duration of each hop is [duration missing]. It consists of 65 symbol periods, with the first 32 symbol periods carrying synchronization or data information, and the last 33 symbol periods being idle. The frequency hopping rate is approximately 76923 hops / s. Each time slot lasts for 7.8125 ms and includes coarse synchronization. Jump, fine synchronization Jump, Header Jump. Each time slot transmits a header and several message words, where the header contains 35 bits of information and each message word contains 75 bits of information. The above symbol " " indicates that the signal is transmitted twice in a whole hop. The modulation method is Minimum Shift Keying (MSK) Cascaded Cyclic Code Shift Keying (CCSK) soft spread spectrum, and the signal is encoded as (31,15) Reed-Solomon (RS) code.

[0113] The Link-16 data link can use four message encapsulation structures per timeslot: Standard Double Pulse (STDP), Packed-2 Single Pulse (P2SP), Packed-2 Double Pulse (P2DP), and Packed-4 Single Pulse (P4SP). The number of message words transmitted are 3, 6, 6, and 12 respectively, with each message word containing 70 bits of information. STDP and P2SP contain time-variable jitter, while P2DP and P4SP do not. Each message encapsulation structure includes a 35-bit header using (16,7) RS code, which is truncated from (31,15) RS code.

[0114] STDP is a standard dual-pulse encapsulation structure, including time-variable jitter. The jitter and transmission protection together occupy 4.4585ms. This mode transmits 3 message words, occupying a total of... Jump.

[0115] P2SP uses a two-single-pulse encapsulation structure, including time-variable jitter. The jitter and transmission protection together occupy 4.4585ms. This mode transmits 6 message words, with each 3 message words occupying 93 hops, for a total of 186 hops.

[0116] P2DP uses a two-pulse encapsulation structure, is jitter-free, and has a transmission protection period of 2.0405ms. This mode transmits 6 message words, with each 3 message words occupying a specific time. Jumps, totaling 372 jumps.

[0117] P4SP uses a 4-single-pulse encapsulation structure, is jitter-free, and has a transmission protection period of 2.0405ms. This mode transmits 12 message words, with each 3 message words occupying 93 hops, for a total of 372 hops.

[0118] Figure 4 An improved time-slot structure for the STDP and P2SP packaging structures is shown. Figure 5 The improved time slot structures of the P2DP and P4SP encapsulation structures are shown. In these improved time slot structures, the basic framework remains consistent with the Link-16 standard; that is, the synchronization, header and data lengths, and the number of hops remain unchanged. The changes are the replacement of RS codes and CCSKs with enhanced Turbo codes, and the replacement of incoherent systems with coherent systems. Enhanced Turbo codes are Turbo codes with a code rate less than the standard Turbo code rate (specifically 1 / 3), for example, a code rate of 1 / 5.

[0119] Figure 6 An improved skip structure is shown in the improved time-slot structure of the package structure STDP and P2SP. Figure 7 The improved hop structure in the improved time-slot structure of the package structures P2DP and P4SP is shown. In the improved hop structure, the duty cycle is the same as the Link-16 standard, i.e., 32:33. The change is that a training sequence is inserted in the first 32 symbol periods, where the training sequence length is 12 symbols for STDP and P2DP, and 8 symbols for P2SP and P4SP.

[0120] When using the direct mapping method for OSTBC, after searching, the following four sets of synchronization symbol sequences are obtained for each number of transmit antennas:

[0121] When the number of transmitting antennas is At that time, the synchronization symbol sequence is

[0122] .

[0123] When the number of transmitting antennas is At that time, the synchronization symbol sequence is

[0124] .

[0125] When the number of transmitting antennas is At that time, the synchronization symbol sequence is

[0126] .

[0127] In some feasible implementations, the embodiments of the present invention may employ the following time slot parameters.

[0128] With STDP encapsulation, the message word length is... Bits, total code length is Bits. The rate matching method is as follows: 1 bit is added to the 255 source bits to obtain 226 encoded bits. Turbo encoding is performed on them at a base code rate of 1 / 5 to obtain a base code of length 1130. The entire code is repeated 3 times and the first 330 bits are repeated to obtain a total code of length 3720.

[0129] With a P2SP encapsulation structure, the message word length is... Bits, total code length is Bits. The rate matching method is as follows: 450 source bits are padded with 0 bits to obtain 450 encoded bits. Turbo encoding is performed on them at a base code rate of 1 / 5 to obtain a base code of length 2250. The first 2214 bits are repeated to obtain a total code of length 4464.

[0130] With a P2DP encapsulation structure, the message word length is... Bits, total code length is Bits. The rate matching method is as follows: 450 source bits are padded with 0 bits to obtain 450 encoded bits, which are then Turbo encoded at a base code rate of 1 / 5 to obtain a base code of length 2250. The entire code is repeated 3 times and the first 690 bits are repeated to obtain a total code of length 7440.

[0131] With a P4SP encapsulation structure, the message word length is... Bits, total code length is Bits. The rate matching method is as follows: 900 source bits are padded with 0 bits to obtain 900 encoded bits, which are then Turbo encoded at a base code rate of 1 / 5 to obtain a base code of length 4500. The first 4428 bits are repeated to obtain a total code of length 8928.

[0132] The following simulation experiments demonstrate the anti-interference performance of the spatial filtering in each embodiment of the present invention. Due to space limitations, only the STDP package structure is selected as an example to verify the performance. The performance verification results of other package structures are similar and will not be elaborated here.

[0133] In the simulation, the MIMO channel is assumed to exhibit Rayleigh fading characteristics, and the number of transmitter and jammer antennas are respectively... and The number of receiver antennas is or The transmitted signal is Alamouti. OSTBC, the interference signal is full-band Gaussian white noise.

[0134] In the performance simulation of the synchronization segment, the number of synchronization jumps is set to 40 according to the current standard, with a blank space of length 100 before and after each jump signal. When the synchronization is accurate, there will be a significant correlation peak at the position of x-axis 100, while other positions are basically flat.

[0135] Figure 8 This is a schematic diagram illustrating the synchronization performance of the conventional maximum ratio combining technique in related technologies under interference-free conditions (signal-to-noise ratio of 0dB). Figure 9 This is a schematic diagram illustrating the synchronization performance of a spatial filtering method for a multiple-input multiple-output system in a Rayleigh channel according to an embodiment of the present invention, using a synchronization segment under interference-free conditions. In this case, both conventional MRC combining and spatial filtering can be synchronized normally.

[0136] Figure 10 This is a schematic diagram illustrating the synchronization performance of the conventional maximum ratio combining technology in related technologies under interference conditions (taking a signal-to-noise ratio of 0dB and an interference-to-signal ratio of 30dB as an example). Figure 11This is a schematic diagram illustrating the synchronization performance of a spatial filtering method for a multiple-input multiple-output (MIMO) system in a Rayleigh channel under interference conditions, according to an embodiment of the present invention. In this case, conventional MRC combining completely fails, while the spatial filtering scheme proposed in this invention can still synchronize normally. Moreover, as long as the synchronization threshold is set between 100 and 120, synchronization can be successfully achieved regardless of the presence or absence of interference.

[0137] Due to space limitations, the data segment simulation only demonstrates the error performance of the STDP package structure, while the transmit diversity uses OSTBC.

[0138] Figure 12 This is a schematic diagram of the bit error rate (BER) of a spatial filtering method for a multiple-input multiple-output system in a Rayleigh channel according to an embodiment of the present invention under interference-free conditions. Figure 13 This is a schematic diagram illustrating the block error rate (BRR) of a spatial filtering method for a multiple-input multiple-output (MIMO) system in a Rayleigh channel according to an embodiment of the present invention under interference-free conditions. Under interference-free conditions, it includes "CSI" (Content Indicator Sequence Information) where the receiver possesses ideal channel information, "MRC" (Maximum Ratio Combining) reception using training sequence estimation, and "SWF" (Spatial Filtering). The number of receiving antennas is as follows: or Compared to the availability of ideal channel information, the performance loss of "MRC" estimated using training sequences exceeds 4 dB, while SWF incurs an additional loss of approximately 0.5 dB. However, in the Rayleigh channel, the 0.5 dB difference is negligible.

[0139] Figure 14 This is a schematic diagram of the bit error rate of a spatial filtering method for a multiple-input multiple-output system in a Rayleigh channel according to an embodiment of the present invention under interference conditions. Figure 15 This is a schematic diagram illustrating the block error rate (BRR) of a spatial filtering method for a multiple-input multiple-output (MIMO) system in a Rayleigh channel according to an embodiment of the present invention under interference conditions. Under interference conditions, the method includes "CSI" (Content Indicator Sequence Information) where the receiver possesses ideal channel information, "MRC" (Maximum Ratio Combining) reception using training sequence estimation, and "SWF" (Spatial Filtering). The number of receiving antennas is as follows: or The signal-to-interference ratio is 30 dB. This is due to the use of... Space-time code, when the number of receiving antennas is At this time, regardless of the receiving method used, the entire transmission structure has no anti-interference capability. At this time, regardless of whether the receiver has an ideal channel estimate, conventional MRC cannot be used for normal reception. Only spatial filtering can achieve normal reception. Compared with interference-free conditions under the same configuration, when there is interference with an interference ratio of 30dB, the performance of spatial filtering only degrades by 3.5dB.

[0140] It should be noted that this invention employs a spatial filtering weight matrix design adapted to MIMO systems. For Rayleigh channels, a weight coefficient matrix suitable for MIMO signals is proposed. Weights are determined based on the MMSE (Man Machine System Engineering, minimum mean square error) criterion, and interference is canceled by weighted summation of the received signals from each path. This overcomes the limitations of traditional SIMO systems and adds a dimension to signal transmission.

[0141] It should be noted that this invention adopts a synchronization method under strong interference across the entire frequency band, designs a synchronization sequence using STBC signals, proposes a measurement criterion, and combines hypothesis testing methods to achieve anti-interference of the synchronization segment, thus solving the problem of neglecting anti-interference of the synchronization segment in traditional research.

[0142] It should be noted that this invention adopts targeted improvements to the Link-16 data link, replacing the original encoding with enhanced Turbo codes, replacing the incoherent system with a coherent system, and adding training sequences to each hop to adapt to the transmission requirements of STBC.

[0143] It should be noted that the present invention adopts full-link anti-interference coverage, and the scheme covers both the data segment and the synchronization segment at the same time. It can still stably synchronize and receive data under a high interference-to-signal ratio of 30dB, and ensure the diversity gain of the MIMO system.

[0144] It should be noted that the transmitted signal adapted by this invention is upgraded from 1-dimensional to 2-dimensional. Traditional spatial interference mitigation methods, despite adding receiving antennas at the receiver, are only applicable to signals with a single transmitting antenna. The adapted signal of traditional methods is essentially a 1-dimensional signal that only relates to the time domain. Currently, space-time codes, as 2D space-time signals, are widely used and can effectively combat the widespread multipath fading on the ground. Traditional methods cannot solve the interference mitigation problem of space-time code transmission, while this invention can increase interference mitigation capability in Rayleigh channels while maintaining diversity gain.

[0145] It should be noted that this invention proposes a spatial filtering weight matrix adapted to MIMO systems. Currently, regardless of existing array signal processing or diversity signal processing, the weighting coefficients appear in the form of vectors, i.e., the so-called "weight vectors". This invention introduces the concept of a "weight matrix" for the first time and provides the derivation process of the optimal weight matrix under the MMSE criterion.

[0146] It should be noted that this invention proposes a synchronization signal design and synchronization strategy suitable for STBC signals. Traditional STBC coding methods in MIMO systems mainly focus on the data segment, while the synchronization segment still uses traditional synchronization sequences, resulting in limited diversity gain. This invention designs a synchronization sequence using STBC signals, provides measurement criteria, proposes a synchronization strategy, and combines hypothesis testing methods to achieve interference immunity in the synchronization segment, thus addressing the problem of neglecting interference immunity in traditional research.

[0147] The beneficial effects of this invention are that, through a spatial filtering anti-interference scheme for a multiple-input multiple-output (MIMO) system based on space-time block codes, the weight matrix is ​​obtained using the training sequence based on the minimum mean square error criterion, and interference is canceled by weighted summation of signals between receiving antennas. This achieves superior anti-interference performance for Rayleigh channel MIMO systems. Furthermore, through data filtering and synchronization strategies, the anti-interference capability of the entire link can be improved and guaranteed.

[0148] The spatial filtering device for a multiple-input multiple-output (MIMO) system in a Rayleigh channel provided by this invention is described below. The spatial filtering device for a MIMO system in a Rayleigh channel described below can be referred to in correspondence with the spatial filtering method for a MIMO system in a Rayleigh channel described above.

[0149] Figure 16 This is a schematic diagram of the spatial filtering device for a multiple-input multiple-output system in a Rayleigh channel provided by the present invention. Based on any of the above embodiments, as... Figure 16 As shown, the device includes an acquisition module 1601 and a filtering module 1602, wherein:

[0150] The acquisition module 1601 is used to acquire the first weight coefficient matrix based on the training sequence in the received signal of each antenna according to the minimum mean square error criterion.

[0151] The filtering module 1602 is used to perform weighted merging of each received signal based on the first weighting coefficient matrix in order to perform spatial filtering on each received signal.

[0152] The spatial filtering device for a multiple-input multiple-output (MIMO) system in a Rayleigh channel provided in this embodiment of the invention is used to execute the spatial filtering method for a multiple-input multiple-output (MIMO) system in a Rayleigh channel described above. Its implementation method is consistent with that of the spatial filtering method for a multiple-input multiple-output (MIMO) system in a Rayleigh channel provided by this invention, and can achieve the same beneficial effects. Therefore, it will not be described again here.

[0153] The spatial filtering device for a Rayleigh channel multiple-input multiple-output system is used in the spatial filtering methods for Rayleigh channel multiple-input multiple-output systems described in the foregoing embodiments. Therefore, the descriptions and definitions in the spatial filtering methods for Rayleigh channel multiple-input multiple-output systems described in the foregoing embodiments can be used to understand the execution modules in the embodiments of the present invention.

[0154] Figure 17 An example is a schematic diagram of the physical structure of an electronic device, such as... Figure 17 As shown, the electronic device may include a processor 1710, a communications interface 1720, a memory 1730, and a communication bus 1740. The processor 1710, communications interface 1720, and memory 1730 communicate with each other via the communication bus 1740. The processor 1710 can call logic instructions in the memory 1730 to execute a spatial filtering method for a multiple-input multiple-output system in a Rayleigh channel. This method includes: obtaining a first weighting coefficient matrix based on a minimum mean square error criterion and a training sequence from the received signals of each antenna; and weighting and combining the received signals based on the first weighting coefficient matrix to perform spatial filtering on each received signal.

[0155] Furthermore, the logical instructions in the aforementioned memory 1730 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0156] The processor 1710 in the electronic device provided in this embodiment of the invention can call the logic instructions in the memory 1730. Its implementation method is consistent with the implementation method of the spatial filtering method of the multiple input multiple output system in the Rayleigh channel provided by this invention, and can achieve the same beneficial effect. It will not be described again here.

[0157] On the other hand, the present invention also provides a computer program product, the computer program product comprising a computer program stored on a non-transitory computer-readable storage medium, the computer program comprising program instructions, wherein when the program instructions are executed by a computer, the computer is able to execute the spatial filtering method for a multiple-input multiple-output system in a Rayleigh channel provided by the methods described above, the method comprising: obtaining a first weighting coefficient matrix based on a minimum mean square error criterion and a training sequence in the received signals of each antenna; and performing weighted merging of each received signal based on the first weighting coefficient matrix to perform spatial filtering on each received signal.

[0158] When the computer program product provided in this embodiment of the invention is executed, it implements the spatial filtering method for a multiple-input multiple-output system in a Rayleigh channel as described above. Its specific implementation method is consistent with the implementation method described in the aforementioned method embodiments, and can achieve the same beneficial effects, which will not be repeated here.

[0159] In another aspect, the present invention also provides a non-transitory computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the spatial filtering method for the multiple-input multiple-output system in the Rayleigh channel provided above. The method includes: obtaining a first weighting coefficient matrix based on a minimum mean square error criterion and a training sequence in the received signals of each antenna; and performing weighted merging of the received signals based on the first weighting coefficient matrix to perform spatial filtering on the received signals.

[0160] When the computer program stored on the non-transitory computer-readable storage medium provided in this embodiment of the invention is executed, it implements the spatial filtering method for the multiple-input multiple-output system in the Rayleigh channel described above. Its specific implementation method is consistent with the implementation method described in the aforementioned method embodiment and can achieve the same beneficial effect, so it will not be repeated here.

[0161] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0162] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0163] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0164] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0165] The foregoing description of specific exemplary embodiments of the invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. The scope of the invention is intended to be defined by the claims and their equivalents.

[0166] The foregoing description of specific exemplary embodiments of the invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. A spatial filtering method for a multiple-input multiple-output system in a Rayleigh channel, characterized in that, include: Based on the minimum mean square error criterion, the first weighting coefficient matrix is ​​obtained according to the training sequence in the received signals of each antenna; Based on the first weighting coefficient matrix, the received signals are weighted and combined to perform spatial filtering on each received signal.

2. The spatial filtering method for a multiple-input multiple-output system in a Rayleigh channel according to claim 1, characterized in that, Before performing weighted merging of the received signals based on the first weighting coefficient matrix to perform spatial filtering on the received signals, the method further includes: The second weighting coefficient matrix is ​​obtained based on the synchronization sequence in each of the received signals; Based on the second weighting coefficient matrix, the received signals are weighted and combined to perform spatial filtering on each received signal and obtain an estimated signal. Synchronization of each received signal is performed based on the estimated signal.

3. The spatial filtering method for a multiple-input multiple-output system in a Rayleigh channel according to claim 1, characterized in that, The first weighting coefficient matrix, obtained based on the minimum mean square error criterion and the training sequence in the received signals of each antenna, includes: Based on the minimum mean square error criterion, the cross-correlation matrix between each received signal and each transmitted signal is obtained according to the training sequence. Based on the cross-correlation matrix, the first weight coefficient matrix is ​​obtained.

4. The spatial filtering method for a multiple-input multiple-output system in a Rayleigh channel according to claim 2, characterized in that, The step of obtaining the second weighting coefficient matrix based on the synchronization sequence in each of the received signals includes: Based on the synchronization sequence, the first arithmetic mean of the autocorrelation matrix sequence of each of the received signals and the second arithmetic mean of the cross-correlation matrix sequence of each of the received signals and each of the transmitted signals are obtained. The second weight coefficient matrix is ​​obtained based on the first arithmetic mean and the second arithmetic mean.

5. The spatial filtering method for a multiple-input multiple-output system in a Rayleigh channel according to claim 2, characterized in that, Before synchronizing the received signals based on the estimated signal, the method further includes: Perform space-time block code mapping on the symbol vector to obtain a three-dimensional matrix sequence; Based on the three-dimensional matrix sequence and the number of transmitting antennas, a metric value is obtained; the metric value is used to determine whether synchronization is successful.

6. The spatial filtering method for a multiple-input multiple-output system in a Rayleigh channel according to claim 3 or 4, characterized in that, The transmitted signal is encapsulated based on the Link-16 data link standard, uses Turbo coding with a code rate lower than the standard code rate of Turbo coding, and the training sequence uses coherent coding.

7. A spatial filtering device for a multiple-input multiple-output system in a Rayleigh channel, characterized in that, include: The acquisition module is used to obtain the first weight coefficient matrix based on the training sequence in the received signals of each antenna according to the minimum mean square error criterion. The filtering module is used to perform weighted merging of each of the received signals based on the first weight coefficient matrix, so as to perform spatial filtering on each of the received signals.

8. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the steps of the spatial filtering method for a multiple-input multiple-output system in a Rayleigh channel as described in any one of claims 1 to 6.

9. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of the spatial filtering method for a multiple-input multiple-output system in a Rayleigh channel as described in any one of claims 1 to 6.

10. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by the processor, it implements the steps of the spatial filtering method for a multiple-input multiple-output system in a Rayleigh channel as described in any one of claims 1 to 6.

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