CN115733716A - Receiver control method, system, equipment and terminal under sudden interference scene - Google Patents
Receiver control method, system, equipment and terminal under sudden interference scene Download PDFInfo
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Abstract
The invention belongs to the technical field of information and communication, and discloses a receiver control method, a system, equipment and a terminal under a sudden interference scene.A small number of silent carriers are set for collecting information of sudden interference, and a covariance matrix of the sudden interference is estimated by using a received signal on the silent carriers and is used for demodulation; designing an MMSE-IRC estimation module A and a soft demodulation noise reduction module B based on the constellation information of the target symbol; in MMSE-IRC estimation module A, MMSE-IRC estimation target signals are made, and in module B, constellation information is used for denoising the input estimation value; the two modules are iterated alternately until convergence. When more symbols in the data frame are subjected to burst interference, the carrier silence scheme provided by the invention can effectively inhibit interference, the performance gain is obvious under high-order modulation, the difference between the performance gain and the interference-free condition can be controlled within 1.5dB, the burst interference is effectively eliminated, and the demodulation performance of a receiver is greatly improved.
Description
Technical Field
The invention belongs to the technical field of information and communication, and particularly relates to a receiver control method, a receiver control system, a receiver control device and a receiver control terminal under a sudden interference scene.
Background
At present, in a 5.5G uplink ultra-wideband scene, refarming F, A and E frequency bands are required to be used for uplink data transmission, but sudden interferences such as atmospheric waveguide interference and intersystem interference exist in the frequency bands, and the performance of a communication system is seriously influenced when the interferences occur. This type of bursty interference originates from outside the communication system and has relatively high energy intensity, and sometimes interference affects only part of the data symbols within one OFDM frame, while the pilot is not interfered, so that the interference cannot be measured through the pilot symbols.
For a general interference suppression algorithm framework, when interference occurs, a cross term of the interference and a target signal occurs, which increases with the increase of the energy of the target signal, and the accuracy of the existing interference covariance measurement method is limited by the cross term, and particularly, the detection performance under high-order modulation is sharply deteriorated compared with that without the cross term. On the other hand, the message passing algorithm under the Bayesian framework can utilize the prior information of target signals or interference to realize noise reduction, and partial interference can be gradually eliminated through iteration among modules. However, the iterative algorithm often lacks prior information of interference or the prior information is weak, so that the iterative algorithm needs to perform a plurality of iterations to achieve a good performance, and especially when the interference occurs on a plurality of data symbols, the demodulation complexity of the whole data frame is high, and the overall efficiency of the algorithm is low. In addition, for the algorithm for reducing noise by using the target signal constellation information, the constellation noise reduction capability is reduced along with the rise of the modulation order, so that the iteration number of the algorithm is increased, and the performance of the algorithm is severely limited.
Under a sudden interference scene, interference of a part of data symbols is not homologous to interference on pilot symbols, a traditional interference suppression framework is difficult to obtain a more accurate interference covariance matrix, and an algorithm designed based on a message transmission framework is limited by the strength of prior information and can be converged to a better result through a plurality of iterations. Therefore, it is desirable to design a new receiver control method in a bursty interference scenario.
Through the above analysis, the problems and defects of the prior art are as follows:
(1) For a general interference suppression algorithm framework, when interference occurs, a cross term of the interference and a target signal occurs, and the cross term is enhanced along with the rise of the energy of the target signal, the accuracy of the existing interference covariance measurement method is limited by the cross term, and particularly, the detection performance under high-order modulation is sharply deteriorated compared with the detection performance without the cross term.
(2) The existing message transfer algorithm under the Bayesian framework lacks prior information of interference or the prior information is weak, so that a plurality of iterations are required to achieve good performance, and particularly when the interference occurs on a plurality of data symbols, the demodulation complexity of the whole data frame is high, and the overall efficiency of the algorithm is low.
(3) For the algorithm for reducing noise by using the target signal constellation diagram information, the constellation diagram noise reduction capability is reduced along with the rise of the modulation order, so that the iteration times of the algorithm are increased, and the performance of the algorithm is severely limited.
Disclosure of Invention
The invention provides a receiver control method, a system, equipment and a terminal in a sudden interference scene aiming at the problem that the existing receiver is lack of sudden interference prior information, and particularly relates to a target signal estimation and demodulation method, a system, a medium, equipment and a terminal in the sudden interference scene based on carrier silence.
The invention is realized in such a way, and the receiver control method under the sudden interference scene comprises the following steps: setting a small number of silent carriers for collecting information of the bursty interference, and estimating a covariance matrix of the bursty interference by using a received signal on the silent carriers and demodulating the covariance matrix; designing an MMSE-IRC estimation module A and a soft demodulation noise reduction module B based on the constellation diagram information of the target symbol; in MMSE-IRC estimation module A, MMSE-IRC estimation target signal is made, and in module B, constellation information is used to reduce noise of input estimation value; the two modules are iterated alternately until convergence.
Further, the receiver control method under the sudden interference scene comprises the following steps:
step one, modeling a system: t is shared in one frame i The OFDM data symbols are affected by burst interference, when the interference does not occur on the pilot symbols and the position of the interference is known, the total bandwidth of the system frequency domain is K =12N RB Sub-carriers, N RB Is the number of resource blocks;
step two, partitioning a model: considering the correlation of channels on adjacent carriers, regarding adjacent R RBs as a sub-block, the system is divided into Q = N RB a/R number of sub-blocks; at the same time will T i The same sub-blocks of the OFDM symbols are spliced, so that the dimension of each sub-block is N r X M, where M = KT i (ii)/Q; the positive effect of the block model is that the channel coefficients on adjacent subcarriers are approximately flat, and the mean value of the interference covariance matrix (finite sample mean value) on each carrier can better approximate the mean value of the interference covariance matrix (mathematical expectation);
step three, carrier silencing: setting P silent carriers in each subblock, wherein the positions of the silent carriers are uniformly distributed in M rows in the subblock, one carrier does not send a target signal every M/P subcarriers in the system, and a received signal on the silent carrier and a received signal on a normal carrier are determined; the positive effect of carrier muting is that it can collect a small number of more accurate interference samples for the receiver in order to extract the interference characteristics;
step four, initializing receiver parameters:
wherein
A priori information representative of the target symbol S in module a,
is a priori value
A priori variance of one N s Vector of x 1, the estimated values of target symbols of different users in the same sub-block correspond to different variances; the reason that the variance of the target symbol adopts a vector form is that different user channel gains have certain differences, and the vector form variance can more accurately depict the phenomenon, so that the variance calculation of the estimated value is more accurate;
step five, constructing an MMSE-IRC estimation module A: estimating a covariance matrix of interference by using a received signal on a silent carrier, and performing MMSE-IRC estimation based on the estimated covariance matrix; in the module A, an interference covariance matrix is estimated based on interference signals collected on silent carriers, so that interference is suppressed and a target symbol is preliminarily estimated;
step six, calculating the external information of the module A: averaging posterior variances of different users in the sub-block, calculating external information of the module A, and inputting the external information of the target symbol into the module B; the positive effect of extrinsic information calculation is the decoupling of the input noise and the output noise of module A;
step seven, constructing a soft demodulation noise reduction module B: using the constellation information of the target symbol to estimate in block B
Noise reduction, n rows and m' columns of elements
Variance of
The nth element of (1); the module B reduces the error of the estimation value (namely the external information output by the module A) of the input module B through the constellation diagram information, so that the estimation value is more accurate relative to the input;
step eight, calculating the external information of the module B: averaging posterior variances of different users in one sub-block, and returning the mean and variance of the extrinsic information of the block B to the block A; the effect of the posterior variance averaging is to reduce the error of the calculation by a larger number of samples;
step nine, if the algorithm converges or reaches the preset maximum iteration times, the algorithm is ended, otherwise, the step five is entered, wherein the MMSE-IRC estimation is carried out on each column in the subblocks to determine the posterior mean value and the variance of the target symbol.
Further, in step one, when the number of the antennas received at the base station end is N r The number of target signal streams is N s The number of interference signal streams is N i The base station receiving signal on the kth subcarrier of the tth data symbol is expressed as:
wherein, the first and the second end of the pipe are connected with each other,
in the case of a target user channel,
in order to interfere with the user channel(s),
in order to be the target signal,
in order to interfere with the signal, it is,
is white noise.
In the second step, the mth column receiving signal in the qth sub-block is:
y q，m ＝H q，m s q，m +H I，q，m s I，q，m +n q，m
＝H q，m s q，m +l q，m +n q，m
the subscript Q, m corresponds to the qK/Q + mod (m-1, K/Q) +1 carrier on the ceil (mQ/K) OFDM data symbol of the system subjected to the burst interference, ceil (x) represents rounding up on x, mod (x, y) represents that x takes a modulo value on y, and l represents that q，m ＝H I，q，m s I，q，m Representing an interfering signal.
Further, in step three, the received signal on the mute carrier is:
l mute，q，p ＝l q，p +n q，p ，
wherein the subscript P corresponds to the (P-1) M/P +1 column of signals in the sub-block. Splicing received signals on silent carriers into matrix form
The received signal on the normal carrier is:
y q，m′ ＝H q，m′ s q，m′ +l q，m′ +n q，m′ ，
wherein m' ≠ p corresponds to the subscript of the non-silent carrier. Splicing received signals on normal carrier waves into a matrix form
The target symbol is expressed in matrix form
The sub-block subscript q is omitted in subsequent steps.
In the fourth step, the abbreviation "pri" of the superscript "is used for representing prior information in the subsequent step, the abbreviation" post "of the superscript" posterior "is used for representing posterior information, the abbreviation" ext "of the superscript" is used for representing external information, different superscripts with the same symbol are used for distinguishing the belonging information categories, and the subscripts A and B respectively represent the modules A and B where the corresponding symbols are located.
Further, the MMSE-IRC estimation module a in step five estimates a covariance matrix of interference using the received signal on the silent carrier, and performing MMSE-IRC estimation based on the estimated covariance matrix includes:
(1) By means of L mute The interference covariance matrix is estimated as:
where P is the number of silent carriers within a single sub-block. In order to solve the problem of rank lacking when the number of estimated samples is less than the dimension of a covariance matrix, the loading base noise is as follows:
wherein the content of the first and second substances,
for background white noise energy intensity, I is the identity matrix.
(2) MMSE-IRC estimation is carried out on each column in the subblock, and the posterior mean value and the variance of the target symbol are respectively as follows:
wherein the content of the first and second substances,
representing a diagonal matrix spanned with vector x as the diagonal element,
and diag (X) denotes taking the diagonal elements of matrix X as column vectors.
The calculation of the information outside the module A in the sixth step comprises the following steps:
taking the average of the posterior variances of different users in the sub-blocks:
the formula for calculating the extrinsic information is as follows:
wherein, u is the Hadamard product.
Further, in step seven, when the target user adopts 2 J Order QAM modulation, one constellation point represents J bits and symbols
Probability of corresponding to kth constellation point
Comprises the following steps:
wherein, c k Represents the kth constellation point and | x | represents the modulo of the complex number x. The posterior mean and variance are respectively:
the calculation of the information outside the module B in the step eight comprises the following steps:
averaging the posterior variances of different users within a sub-block:
the posterior variance is
Splicing the posterior means into a matrix form
The element of the n-th row m' is
The formula for calculating the external information of the module B is as follows:
wherein, an is a Hadamard product.
Another object of the present invention is to provide a receiver control system in a bursty interference scenario applying the receiver control method in the bursty interference scenario, where the receiver control system in the bursty interference scenario includes:
the MMSE-IRC estimation module A is used for estimating an interference covariance matrix by utilizing a received signal on a silent carrier wave and carrying out MMSE-IRC estimation based on the estimated covariance matrix;
and the soft demodulation noise reduction module B is used for reducing noise of the estimated value by using the constellation information of the target symbol.
Another object of the present invention is to provide a computer device, which includes a memory and a processor, wherein the memory stores a computer program, and the computer program, when executed by the processor, causes the processor to execute the steps of the receiver control method in the bursty interference scenario.
Another object of the present invention is to provide a computer-readable storage medium, which stores a computer program, and when the computer program is executed by a processor, the computer program causes the processor to execute the steps of the receiver control method in the bursty interference scenario.
Another objective of the present invention is to provide an information data processing terminal, which is used to implement the receiver control system in the bursty interference scenario.
By combining the technical scheme and the technical problem to be solved, the technical scheme to be protected by the invention has the advantages and positive effects that:
under a burst interference scene, interference of a part of data symbols is not homologous with interference on pilot symbols, a traditional interference suppression framework is difficult to obtain a more accurate interference covariance matrix, and an algorithm designed based on a message transmission framework is limited by the strength of prior information and can be converged to a better result through more iterations. The carrier silencing scheme designed in the invention does not send data symbols on part of subcarriers, can collect a small amount of more accurate interference and estimate an interference covariance matrix according to the small amount of more accurate interference, and then performs noise reduction by combining with constellation information of a target user, so that an algorithm can be converged within fewer iteration times and achieve excellent performance.
The invention provides a carrier silencing scheme aiming at the problem that a receiver is lack of burst interference prior information, in particular to a scheme for silencing a small part of subcarriers in an OFDM system, wherein a target user does not send signals on the silenced carriers and is used for acquiring more accurate interference signals. The signal observed on the silent carrier only comprises two parts of burst interference and background white noise, and the other normal carrier comprises three parts of target signal, interference and noise. The signals collected on the silent carrier waves contain more accurate interference information, and the efficiency of interference elimination can be effectively improved by reasonable utilization. The method estimates a covariance matrix by utilizing interference on a silent carrier and uses the covariance matrix for demodulation, and a demodulation part comprises two modules, namely an MMSE-IRC estimation module A and a soft demodulation noise reduction module B; in module A, MMSE-IRC estimation target signals are performed, and in module B, constellation map information is used for denoising the input estimation values; and the two modules are iterated alternately until the algorithm converges.
According to the invention, a small number of silent carriers are set for collecting information of the bursty interference, the covariance matrix of the bursty interference is estimated by using the received signals on the silent carriers, then two modules are designed for iteration based on the constellation diagram information of the target symbol, the bursty interference is effectively eliminated by an algorithm, and the demodulation performance of a receiver is greatly improved.
When more symbols in a data frame are subjected to burst interference, the carrier silencing scheme provided by the invention can effectively inhibit the interference, the performance gain is obvious under high-order modulation (64 QAM and above), the difference from the interference-free condition can be controlled within 1.5dB, and the influence of the rising of the modulation order on the algorithm performance is weak.
The technical scheme of the invention solves the technical problem that people are eagerly to solve but can not be successfully solved all the time: the problem of bursty interference has been long in wireless communication systems but a better solution is still lacking, especially a means for suppressing or eliminating interference directly at a receiving end, and the problem occurs more frequently with the reduction of cell radius and the increase of transmitter power in a 5G network, especially the performance of a receiver deteriorates seriously under high-order modulation, and the performance of a communication system is severely limited. The technical scheme of the invention can effectively collect interference information based on an iterative algorithm designed by carrier silence, and can effectively eliminate interference by combining with a constellation diagram information design noise reduction module of target data through iteration, and can still obtain quite excellent performance under high-order modulation under the condition of more interfered data symbols, thereby well solving the problem of system performance deterioration caused by burst interference under high-order modulation.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments of the present invention will be briefly described below, and it is obvious that the drawings described below are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.
Fig. 1 is a flowchart of a receiver control method in a bursty interference scenario according to an embodiment of the present invention;
fig. 2 is a block diagram of a receiver according to an embodiment of the present invention;
fig. 3 is a diagram of BLER performance in algorithm demodulation under 64QAM according to an embodiment of the present invention;
fig. 4 is a diagram of performance of algorithm demodulation BLER under 256QAM according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
In view of the problems in the prior art, the present invention provides a method, a system, a device and a terminal for controlling a receiver in a bursty interference scenario, and the following describes the present invention in detail with reference to the accompanying drawings.
This section is an explanatory embodiment expanding on the claims so as to fully understand how the present invention is embodied by those skilled in the art.
As shown in fig. 1, a method for controlling a receiver in a bursty interference scenario provided by the embodiment of the present invention includes the following steps:
s101, setting a small amount of silent carriers for collecting information of the bursty interference;
s102, estimating a covariance matrix of the burst interference by using the received signal on the silent carrier and demodulating the covariance matrix;
s103, designing an MMSE-IRC estimation module A and a soft demodulation noise reduction module B based on the constellation information of the target symbol; in module A, MMSE-IRC estimation target signals are performed, and in module B, constellation map information is used for denoising the input estimation values; the two modules are iterated alternately until convergence.
As a preferred embodiment, the method for controlling a receiver in a bursty interference scenario provided in the embodiment of the present invention specifically includes the following steps:
s1, system modeling: t is shared in one frame i The OFDM data symbols are affected by burst interference, the position of the interference is known (the interference is not assumed to occur on the pilot symbols), and the system frequency domain bandwidth is K =12N RB Sub-carriers, N RB Is the number of Resource Blocks (RBs). Let the number of antennas received at the base station end be N r The number of target signal streams is N s The number of interference signal streams is N i The base station received signal on the kth subcarrier of the tth data symbol can be represented as:
wherein, the first and the second end of the pipe are connected with each other,
in the case of a target user channel,
in order to interfere with the user channel(s),
is a signal that is a target of the signal,
in order to interfere with the signal(s),
is white noise.
S2, partitioning a block model: considering the correlation of channels on adjacent carriers, if the adjacent R RBs are regarded as one sub-block, the system is divided into Q = N EB a/R number of sub-blocks, and T can be simultaneously determined i The same sub-blocks of an OFDM symbol are spliced together, i.e. each sub-block has a dimension of N r X M, where M = KT i and/Q, the m column receiving signal in the Q sub-block is as follows:
y q，m ＝H q，m s q，m +H I，q，m s I，q，m +n q，m
＝H q，m s q，m +l q，m +n q，m
wherein, subscript Q, m corresponds to the qK/Q + mod (m-1, K/Q) +1 carrier on the system ceil (mQ/K) OFDM data symbol subjected to burst interference, ceil (x) represents rounding up to x, mod (x, y) represents the modulo of x to y, l q，m ＝H I，q，m s I，q，m Representing an interfering signal.
S3, carrier silencing: now, P silent carriers are set in each sub-block, and the positions of the silent carriers are uniformly distributed in M columns in the sub-block, that is, in the system, there is one carrier not sending a target signal every M/P subcarriers, and then the received signals on the silent carriers are:
l mute，q，p ＝l q，p +n q，p ，
wherein the subscript P corresponds to the (P-1) M/P +1 column of signals in the sub-block. Splicing received signals on silent carriers into matrix form
The received signal on the normal carrier is:
y q，m′ ＝H q，m′ s q，m′ +l q，m′ +n q，m′ ，
wherein m' ≠ p corresponds to the subscript of the non-silent carrier. Splicing received signals on normal carrier waves into a matrix form
The target symbol is represented in matrix form
Each sub-block is processed separately in subsequent steps and the processing steps are the same, and the sub-block subscript q is omitted in the following for the sake of brevity of notation.
S4, receiver parameter initialization:
wherein
Representing a priori information of the target symbol S in block a,
is a priori value
A priori variance of one N s The x 1 vector, i.e. the target symbol estimates of different users in the same sub-block, correspond to different variances. In the subsequent steps, the abbreviation "pri" of the superscript "is used for representing prior information, the abbreviation" post "of the superscript" posterior "is used for representing posterior information, the abbreviation" ext "of the superscript" is used for representing external information, different superscripts with the same symbol are used for distinguishing the information categories to which the superscripts belong, and the subscripts A and B respectively represent the modules A and B where the corresponding symbols are located.
S5, an MMSE-IRC estimation module A: in the module A, the covariance matrix of interference is estimated by using the received signal on the silent carrier, and then MMSE-IRC estimation is performed based on the estimated covariance matrix.
S51, utilization of L mute The interference covariance matrix is estimated as:
where P is the number of silent carriers within a single sub-block. In order to solve the problem of rank lacking when the number of estimated samples is less than the dimension of a covariance matrix, the loading base noise is as follows:
wherein the content of the first and second substances,
is the background white noise energy intensity, and I is the identity matrix.
S52, MMSE-IRC estimation is carried out on each column in the sub-block, and the posterior mean value and the variance of the target symbol are respectively as follows:
wherein the content of the first and second substances,
representing a diagonal matrix spanned with vector x as the diagonal element,
and diag (X) denotes taking the diagonal elements of matrix X as column vectors.
S6, calculating external information of the module A: the posterior variances of different users in the sub-block are averaged:
the formula for calculating the extrinsic information is as follows:
wherein, u is the Hadamard product. The extrinsic information of the target symbol is then input to module B.
S7, a soft demodulation noise reduction module B: using the constellation information of the target symbol to estimate in block B
Noise reduction, with n rows and m' columns of elements of
Having a variance of
Namely that
The nth element of (a). Targeted user adoption 2 J Order QAM modulation, one constellation point represents J bits, symbols
Probability of corresponding to kth constellation point
Comprises the following steps:
wherein, c k Representing the kth constellation point, | x | representing the modulo of the complex number x. The posterior mean and variance are respectively:
s8, calculating external information of the module B: the posterior variances of different users in a sub-block are averaged:
the posterior variance is
Splicing posterior mean values into matrix form
The element of the n-th row m' is
The formula for calculating the external information of the module B is as follows:
wherein, an is a Hadamard product. The extrinsic information mean and variance of block B are then returned to block a.
And S9, ending if the algorithm converges or reaches the preset maximum iteration number, otherwise, entering the step S52.
The receiver control system in the burst interference scene provided by the embodiment of the invention comprises:
the MMSE-IRC estimation module A is used for estimating an interference covariance matrix by utilizing a received signal on a silent carrier wave and carrying out MMSE-IRC estimation based on the estimated covariance matrix;
and the soft demodulation noise reduction module B is used for reducing noise of the estimated value by using the constellation information of the target symbol.
In order to prove the creativity and the technical value of the technical scheme of the invention, the part is the application example of the technical scheme of the claims on specific products or related technologies.
1. Under the special weather condition, the refractive index of the ionized layer is changed, radio signals are repeatedly refracted in the ionized layer and can be transmitted to a remote area, the energy attenuation is small, and the phenomenon can cause burst interference to a remote base station;
2. if different communication systems exist in one or several adjacent cells, such as cells where an FDD system and a TDD system coexist, bursty interference may be caused between the different systems.
The embodiment of the invention has some positive effects in the process of research and development or use, and indeed has great advantages compared with the prior art, and the following contents are described by combining data, graphs and the like in the experimental process.
The block diagram of the receiver structure provided by the embodiment of the present invention is shown in fig. 2, and includes an MMSE-IRC estimation module a and a soft demodulation noise reduction module B. The algorithm simulation channel is an Urban Macro (UMa) scene channel described in section 7.5 of the 3GPP 38.901 standard, and parameter setting refers to an UMa scene NLOS column in Table 7.5-6Part-1 in the standard. Base station receiving antenna number N in simulation r =64, number of target user streams N s Number of bursty interference streams N =8 i =8, bursty interference IoT of 10 dB/stream, total number of OFDM data symbols in one TTI T =12, number of bursty interference data symbols T i =7, system bandwidth N RB The modulation mode is 64QAM or 256QAM, the channel coding adopts LDPC coding, the coding rate is 3/4, and all OFDM data symbols in a single TTI are coded into a code word. In addition, because the position of the burst interference is known, the data symbols which are not subjected to the burst interference are directly demodulated by adopting an MMSE-IRC algorithm, the data symbols which are subjected to the burst interference are demodulated by adopting the algorithm designed in the invention, and the maximum iteration number is set to be 3. Under the current configuration, the specific implementation manner of the receiver control method in the bursty interference scenario provided by the embodiment of the present invention is as follows:
s1, system modeling: t is shared in one frame i The =7 OFDM data symbols are affected by the burst interference, and the position of the interference is known (assuming that the interference does not occur on the pilot symbols), the system frequency domain bandwidth has K =12N in total RB =288 subcarriers, N RB =4 is the number of Resource Blocks (RBs). Let the number of receiving antennas at the base station end be N r =64, target signal stream number N s =8, number of interfering signal streams N i =8, the base station received signal on the kth subcarrier of the tth data symbol can be represented as:
wherein the content of the first and second substances,
in the case of a target user channel,
in order to interfere with the user channel(s),
is a signal that is a target of the signal,
in order to interfere with the signal, it is,
is white noise.
S2, partitioning a block model: considering the correlation of channels on adjacent carriers, if adjacent R =4 RBs is regarded as one sub-block, the system is divided into Q =6 sub-blocks altogether, and T may be considered as a whole i The same sub-blocks of =7 OFDM symbols are spliced together, that is, each sub-block has a dimension of 64 × 336, and the m-th column of received signals in the q-th sub-block is:
y q，m ＝H q，m s q，m +H I，q，m s I，q，m +n q，m
＝H q，m s q，m +l q，m +n q，m
wherein, subscript q, m corresponds to 48q + mod (m-1, 48) +1 carrier on the ceil (m/48) th burst interfered OFDM data symbol of the system, ceil (x) represents rounding up x, mod (x, y) represents x modulo y, l modulo y represents q，m ＝H I，q，m s I，q，m Representing an interfering signal.
S3, carrier silencing: now, P =84 quiet carriers are set in each sub-block, and the positions of the quiet carriers are uniformly distributed in M =336 columns in the sub-block, i.e. one carrier does not transmit the target signal every M/P =4 sub-carriers in the system, then the received signal on the quiet carrier is:
l mute，q，p ＝l q，p +n q，p ，
where the subscript p corresponds to the 4 (p-1) +1 column signal in the sub-block. Splicing received signals on silent carriers into matrix form
The received signal on the normal carrier is:
y q，m′ ＝H q，m′ s q，m′ +l q，m′ +n q，m′ ，
where m' ≠ p corresponds to the subscript of the non-silent carrier. Splicing received signals on normal carrier waves into a matrix form
The target symbol is expressed in matrix form
In the subsequent steps, each subblock is processed separately and the processing steps are the same, and the subblock index q is omitted in the following for the sake of brevity of notation.
S4, receiver parameter initialization:
wherein
Representing a priori information of the target symbol S in block a,
is a priori value
The a priori variance of (a) is an 8 × 1 vector, i.e., different variances correspond to different user target symbol estimates within the same sub-block. Using superscript "prior" in subsequent stepsThe abbreviation "pri" represents prior information, the abbreviation "post" of the superscript "posterior" represents posterior information, the abbreviation "ext" of the superscript "externic" represents external information, the same symbol and different superscripts are used for distinguishing the information categories to which the information belongs, and the subscripts A and B respectively represent the modules A and B in which the corresponding symbols are located.
S5, an MMSE-IRC estimation module A: in the module A, the covariance matrix of interference is estimated by using the received signal on the silent carrier, and then MMSE-IRC estimation is carried out based on the estimated covariance matrix.
S51, utilization of L mute The interference covariance matrix is estimated as:
where P =84 is the number of silent carriers within a single sub-block. In order to solve the problem of rank lacking when the number of estimated samples is less than the dimension of a covariance matrix, the loading base noise is as follows:
wherein the content of the first and second substances,
for background white noise energy intensity, I is the identity matrix.
S52, MMSE-IRC estimation is carried out on each column in the sub-block, and the posterior mean value and the variance of the target symbol are respectively as follows:
wherein the content of the first and second substances,
representing a diagonal matrix spanned with vector x as the diagonal element,
and diag (X) denotes taking the diagonal elements of matrix X as column vectors.
S6, calculating external information of the module A: the posterior variances of different users in the sub-block are averaged:
the formula for calculating the extrinsic information is as follows:
wherein, an is a Hadamard product. The extrinsic information of the target symbol is then input to module B.
S7, a soft demodulation noise reduction module B: using the constellation information pair estimate of the target symbol in block B
Noise reduction, with n rows and m' columns of elements of
The variance is
Namely, it is
The nth element of (1). Targeted user adoption 2 J =64 QAM modulation, one constellation point represents J =6 bits, symbol
Probability of corresponding to kth constellation point
Comprises the following steps:
wherein, c k Representing the kth constellation point, | x | representing the modulo of the complex number x. The posterior mean and variance are respectively:
s8, calculating the external information of the module B: the posterior variances of different users in a sub-block are averaged:
the posterior variance is
Splicing the posterior means into a matrix form
The element of the n-th row m' is
The formula for calculating the external information of the module B is as follows:
wherein, u is the Hadamard product. The extrinsic information mean and variance of block B are then returned to block a.
And S9, ending if the algorithm converges or reaches the preset maximum iteration number, otherwise, entering the step S52.
Fig. 3 and 4 show BLER performance curves for 64QAM and 256QAM modulations when 7 OFDM data symbols in a data frame are subject to bursty interference, respectively. The horizontal axis is the strength of a target user signal relative to the background noise, the vertical axis is the data demodulation BLER, wherein a curve mute-scheme corresponds to a carrier silencing scheme provided by the invention, a curve Interference-free corresponds to the condition that no data symbol is subjected to sudden Interference, a curve C-TMP-Opt corresponds to the result of 10 times of algorithm iteration based on the design of a message transmission framework, the constellation diagram information of the target signal and the low rank of an Interference signal are mainly utilized, and a curve LMMSE corresponds to the condition that the sudden Interference is treated as white noise.
At BLER =0.1, when the modulation mode is 64QAM, the mute-scheme obtains 14dB performance gain compared with an LMMSE algorithm, obtains 5.5dB performance gain compared with a C-TMP-Opt algorithm, and controls the performance difference between the mute-scheme and the non-interference condition within 1.5 dB; when the modulation order is increased to 256QAM, the difference between the mute-scheme and the interference-free condition is still less than 1.5dB, the difference between the mute-scheme and the LMMSE algorithm is still maintained at about 14dB, but the difference is 7dB gain compared with the C-TMP-Opt algorithm, and is 1.5dB higher than that under the condition of 64QAM, the main reason is that the noise reduction capability of the C-TMP-Opt algorithm is reduced as the constellation point density is increased along with the increase of the modulation order, and the performance of the C-TMP-Opt algorithm is lost depending on the noise reduction capability of a constellation diagram. The carrier silencing scheme provided by the invention utilizes partial carriers to acquire the information of the burst interference, and the dependence of the algorithm on the constellation map information is greatly reduced without being limited by the modulation order and the constellation map density.
To sum up, when there are many symbols in the data frame that are subject to the burst interference, the carrier muting scheme provided by the present invention can effectively suppress the interference, the performance gain is obvious under the high-order modulation (64 QAM and above), the difference from the interference-free situation can be controlled within 1.5dB, and the influence of the rise of the modulation order on the algorithm performance is weak.
It should be noted that embodiments of the present invention can be realized in hardware, software, or a combination of software and hardware. The hardware portions may be implemented using dedicated logic; the software portions may be stored in a memory and executed by a suitable instruction execution system, such as a microprocessor or specially designed hardware. Those skilled in the art will appreciate that the apparatus and methods described above may be implemented using computer executable instructions and/or embodied in processor control code, such code being provided on a carrier medium such as a disk, CD-or DVD-ROM, programmable memory such as read only memory (firmware), or a data carrier such as an optical or electronic signal carrier, for example. The apparatus and its modules of the present invention may be implemented by hardware circuits such as very large scale integrated circuits or gate arrays, semiconductors such as logic chips, transistors, etc., or programmable hardware devices such as field programmable gate arrays, programmable logic devices, etc., or by software executed by various types of processors, or by a combination of hardware circuits and software, e.g., firmware.
The above description is only for the purpose of illustrating the embodiments of the present invention, and the scope of the present invention should not be limited thereto, and any modifications, equivalents and improvements made by those skilled in the art within the technical scope of the present invention as disclosed in the present invention should be covered by the scope of the present invention.
Claims (10)
1. A receiver control method in a burst interference scene is characterized by comprising the following steps: setting a small number of silent carriers for collecting information of the bursty interference, and estimating a covariance matrix of the bursty interference by using a received signal on the silent carriers and demodulating the covariance matrix; designing an MMSE-IRC estimation module A and a soft demodulation noise reduction module B based on the constellation information of the target symbol; in MMSE-IRC estimation module A, MMSE-IRC estimation target signal is made, and in soft demodulation noise reduction module B, constellation information is used for noise reduction of input estimation value; the two modules are iterated alternately until convergence.
2. The method for controlling a receiver in a bursty interference scenario of claim 1, wherein the method for controlling a receiver in a bursty interference scenario comprises the steps of:
step one, modeling a system: t is shared in one frame i The OFDM data symbols are affected by burst interference, when the interference does not occur on the pilot symbols and the position of the interference is known, the total bandwidth of the system frequency domain is K =12N RB Subcarrier, N RB Is the number of resource blocks;
step two, partitioning a model: considering the correlation of channels on adjacent carriers, regarding adjacent R RBs as a sub-block, the system is divided into Q = N RB a/R number of sub-blocks; at the same time will T i The same sub-blocks of the OFDM symbols are spliced, so that the dimension of each sub-block is N r X M, where M = KT i /Q；
Step three, carrier silencing: setting P silent carriers in each sub-block, wherein the positions of the silent carriers are uniformly distributed in M rows in the sub-block, and one carrier does not send a target signal every M/P sub-carriers in the system, so as to determine a received signal on the silent carrier and a received signal on a normal carrier;
step four, initializing receiver parameters:
wherein
Representing a priori information of the target symbol S in block a,
is a priori value
A priori variance of one N s Vector of x 1, the estimated values of target symbols of different users in the same sub-block correspond to different variances;
step five, constructing an MMSE-IRC estimation module A: estimating a covariance matrix of interference by using a received signal on a silent carrier, and performing MMSE-IRC estimation based on the estimated covariance matrix;
step six, calculating the external information of the module A: averaging posterior variances of different users in the sub-block, calculating external information of the module A, and inputting the external information of the target symbol into the module B;
step seven, constructing a soft demodulation noise reduction module B: in module B usingConstellation information pair estimation value of target symbol
Noise reduction, n rows and m' columns of elements
Variance of
The nth element of (1);
step eight, calculating the external information of the module B: averaging posterior variances of different users in one sub-block, and returning the mean and variance of the extrinsic information of the block B to the block A;
step nine, if the algorithm converges or reaches the preset maximum iteration times, ending, otherwise, entering the step five of performing MMSE-IRC estimation on each column in the subblock to determine the posterior mean value and the variance of the target symbol.
3. The method of claim 2, wherein in step one, when the number of antennas received at the base station is N, the receiver control method is characterized in that r The number of target signal streams is N s The number of interference signal streams is N i The base station receiving signal on the kth subcarrier of the tth data symbol is expressed as:
wherein the content of the first and second substances,
in the case of a target user channel,
in order to interfere with the user channel(s),
is a signal that is a target of the signal,
in order to interfere with the signal, it is,
is white noise;
in the second step, the mth column receiving signal in the qth sub-block is:
y q，m ＝H q，m s q，m +H I，q，m s I，q，m +n q，m
＝H q，m s q，m +l q，m +n q，m
the subscript Q, m corresponds to the qK/Q + mod (m 1, K/Q) +1 carrier on the ceil (mQ/K) th burst-interfered OFDM data symbol of the system, ceil (x) represents rounding up x, mod (x, y) represents that x takes a modulo value of y, and l represents that x takes a modulo value of y q，m ＝H I，q， m s I，q，m Representing an interfering signal.
4. The receiver control method under the bursty interference scenario of claim 2, wherein in step three, the received signals on the muted carriers are:
l mute，q，p ＝l q，p +n q，p ，
wherein, the subscript P corresponds to the (P-1) M/P +1 column signal in the sub-block; splicing received signals on silent carriers into matrix form
The received signal on the normal carrier is:
y q，m′ ＝H q，m′ s q，m′ +l q，m′ +n q，m′ ，
wherein m' ≠ p corresponds to a subscript of the non-silent carrier; splicing received signals on normal carrier waves into a matrix form
The target symbol is represented in matrix form
The sub-block subscript q is omitted in subsequent steps;
in the fourth step, the abbreviation "pri" of the superscript "is used for representing prior information in the subsequent step, the abbreviation" post "of the superscript" posterior "is used for representing posterior information, the abbreviation" ext "of the superscript" is used for representing external information, different superscripts with the same symbol are used for distinguishing the belonging information categories, and the subscripts A and B respectively represent the modules A and B where the corresponding symbols are located.
5. The method as claimed in claim 2, wherein the MMSE-IRC estimation module a in step five estimates the covariance matrix of interference by using the received signal on the silent carrier, and the MMSE-IRC estimation based on the estimated covariance matrix comprises:
(1) By means of L mute The interference covariance matrix is estimated as:
wherein, P is the number of the silent carriers in a single subblock; in order to solve the problem of rank lacking when the number of estimated samples is less than the dimension of a covariance matrix, the loading base noise is as follows:
wherein, the first and the second end of the pipe are connected with each other,
taking the background white noise energy intensity as I as a unit matrix;
(2) MMSE-IRC estimation is carried out on each column in the subblock, and the posterior mean value and the variance of the target symbol are respectively as follows:
wherein, the first and the second end of the pipe are connected with each other,
representing a diagonal matrix spanned with vector x as the diagonal element,
and diag (X) represents taking diagonal elements of the matrix X as column vectors;
the calculation of the information outside the module A in the sixth step comprises the following steps:
taking the mean of the posterior variances of different users in the sub-block:
the formula for calculating the extrinsic information is as follows:
wherein, an is a Hadamard product.
6. The method for controlling a receiver in a bursty interference scenario of claim 2, wherein in step seven, when the target user employs 2 J Order QAM modulation, one constellation point represents J bits, symbols
Probability of corresponding to kth constellation point
Comprises the following steps:
wherein, c k Representing the kth constellation point, | x | represents the modulus of the complex number x; the posterior mean and variance are respectively:
the calculation of the information outside the module B in the step eight comprises the following steps:
averaging the posterior variances of different users within a sub-block:
the posterior variance is
Splicing posterior mean values into matrix form
The element of the n-th row m' is
The formula for calculating the external information of the module B is as follows:
wherein, an is a Hadamard product.
7. A receiver control system in a bursty interference scenario applying the receiver control method in the bursty interference scenario according to any one of claims 1 to 6, wherein the receiver control system in the bursty interference scenario comprises:
an MMSE-IRC estimation module A, which is used for estimating the covariance matrix of interference by using the received signals on the silent carrier and carrying out MMSE-IRC estimation based on the estimated covariance matrix;
and the soft demodulation and noise reduction module B is used for reducing noise of the estimated value by using the constellation information of the target symbol.
8. A computer arrangement, characterized in that the computer arrangement comprises a memory and a processor, the memory storing a computer program which, when executed by the processor, causes the processor to carry out the steps of the receiver control method in a bursty interference scenario as claimed in any one of claims 1 to 6.
9. A computer readable storage medium, storing a computer program which, when executed by a processor, causes the processor to perform the steps of the receiver control method in a bursty interference scenario as claimed in any one of claims 1 to 6.
10. An information data processing terminal characterized in that the information data processing terminal is adapted to implement the receiver control system in a bursty interference scenario as claimed in claim 7.
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