CN107079374A

CN107079374A - A kind of interference cancellation method and equipment

Info

Publication number: CN107079374A
Application number: CN201580001376.7A
Authority: CN
Inventors: 吕捷
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2015-05-08
Filing date: 2015-05-08
Publication date: 2017-08-18
Anticipated expiration: 2035-05-08
Also published as: WO2016179759A1; CN107079374B

Abstract

The embodiment of the invention discloses a kind of interference cancellation method and equipment, it is related to communication technical field, to offset the interference in the data that receiving device is received, improves the reliability of data transfer.Method provided in an embodiment of the present invention includes：Receive the first signal；Obtain Interference Cancellation matrix；The Interference Cancellation matrix includes M Interference Cancellation vector, each Interference Cancellation vector includes Nr Interference Cancellation coefficient, and the vectorial vectorial degree of correlation of interference characteristic of the interference source on Nr reception antenna any of with N number of interference source of each Interference Cancellation is less than the first predetermined threshold value；The M is the number of the Interference Cancellation vector pre-set；The N is the number of the interference pre-set；Data flow is obtained by the Interference Cancellation matrix and first signal multiplication, and by the signal demodulation after multiplication.

Description

Interference cancellation method and equipment

Technical Field

The present invention relates to the field of communications technologies, and in particular, to an interference cancellation method and apparatus.

Background

With the development of communication technology, Wireless Local Area Networks (WLANs) have become more and more widely used. A WLAN is a network formed by replacing part or all of transmission media in a wired local area network with wireless channels of various radio waves (such as laser, infrared, radio frequency, etc.). The WLAN includes WIreless transmission technologies such as WIreless-FIdelity (Wi-Fi), Bluetooth (Bluetooth), Zigbee, Licensed-Assisted Access (LAA), and all use high frequency radio frequency as a transmission medium.

Because various radio applications including Wi-Fi, radar, bluetooth, Zigbee, LAA, and the like are carried in each frequency band of the high-frequency radio frequency band, and different protocols affect and interfere with each other, in the WLAN system, even if the same Wi-Fi protocol is used, data between different Wireless Access Points (APs) may affect each other, and in addition, some household appliances, such as a microwave oven, a toy remote controller, and a mother and infant monitoring device, may also generate high-frequency interference. In order to avoid adverse effects caused by interference, in a WLAN system, a Carrier Sense Multiple Access (Carrier Sense Multiple Access) with Collision Avoidance (CSMA/CA) mechanism is usually adopted to avoid interference caused by Collision of data transmitted by Multiple users.

In CSMA/CA, each station first monitors whether the channel is idle before starting to transmit data, if the channel is idle, the station starts to wait for a random backoff period during which the station continues to perform channel monitoring, and if the channel is still idle until the end of the wait period, the station starts to transmit; if the channel is monitored to be busy, the station must delay to the end of the current transmission, choose a random backoff period, continue monitoring in the period, and if the channel is still idle until the waiting period is over, the station starts to transmit. In this way, the CAMA/CA mechanism can avoid transmitting data when interference occurs, so as to avoid that the transmission content is "polluted" by the interference.

Although the CSMA/CA mechanism has a certain alleviating effect on the effect of interference, the following drawbacks exist: if the interference occurs after the data transmission starts and before the data transmission ends, the back-off mechanism fails, and the data received by the receiving device is still damaged by the interference, which reduces the reliability of data transmission.

Disclosure of Invention

The invention provides an interference cancellation method and equipment, which are used for canceling interference in data received by receiving equipment and improving the reliability of data transmission.

In order to achieve the above purpose, the embodiment of the invention adopts the following technical scheme:

in a first aspect, an embodiment of the present invention provides an interference cancellation method, which is applied to a receiving device, where the receiving device is configured with Nr receiving antennas, and is configured to receive signals output by Nt transmitting antennas or spatial streams or spatial-temporal streams, where Nr is an integer greater than or equal to 2, and Nt is an integer greater than or equal to 1; the method comprises the following steps:

receiving a first signal; the first signal comprises signals and noise signals which are obtained after signals output by Nt sending antennas or space streams or space time streams received by Nr receiving antennas pass through a channel;

acquiring an interference cancellation matrix; the interference cancellation matrix comprises M interference cancellation vectors, each interference cancellation vector comprises Nr interference cancellation coefficients, and the correlation degree between each interference cancellation vector and an interference characteristic vector of any interference source in N interference sources on Nr receiving antennas is smaller than a first preset threshold value; m is the number of preset interference cancellation vectors; n is the number of preset interferences;

and multiplying the interference cancellation matrix and the first signal, and demodulating the multiplied signal to obtain a data stream.

In a first implementable manner of the first aspect, with reference to the first aspect, the obtaining an interference cancellation matrix includes:

receiving a second signal in a first receiving period, wherein the second signal is a signal received by Nr receiving antennas;

estimating channel characteristics of a channel transmitting the second signal from the second signal; wherein the channel characteristics are a matrix of Nr times Nt;

obtaining interference characteristics, wherein the interference characteristics consist of N vectors, and the ith vector is an interference characteristic vector of the ith interference source on the Nr receiving antennas;

and acquiring the interference cancellation matrix according to the channel characteristics and the interference characteristics.

In a second implementation manner of the first aspect, with reference to the first implementation manner of the first aspect, for any interference cancellation vector in the interference cancellation matrix, the obtaining an interference cancellation vector according to the channel characteristic and the interference characteristic includes:

and acquiring one characteristic vector which is perpendicular to an interference characteristic vector in the interference characteristics and has the minimum included angle with the channel characteristics or the characteristic vector which has the included angle with the channel characteristics smaller than a preset angle as the interference offset vector.

In a third implementation manner of the first aspect, with reference to the first implementation manner of the first aspect, the obtaining an interference cancellation matrix according to the channel characteristics and the interference characteristics includes:

combining the channel characteristics and the interference characteristics into a first joint matrix;

performing matrix inversion operation on the first combined matrix to obtain an inverse matrix;

and combining M vectors corresponding to the channel characteristics in the inverse matrix or M vectors subjected to linear combination corresponding to the channel characteristics into the interference cancellation matrix.

In a fourth implementation manner of the first aspect, with reference to the third implementation manner of the first aspect, performing matrix inversion operation on the first joint matrix, and obtaining an inverse matrix includes:

carrying out approximate inversion at least once on the first combined matrix to obtain at least one approximate inverse matrix;

the combining M vectors corresponding to the channel characteristics in the inverse matrix or M linearly combined vectors corresponding to the channel characteristics into the interference cancellation matrix comprises:

respectively calculating the signal-to-noise ratio of the first signal by using M vectors corresponding to the channel characteristics in the at least one approximate inverse matrix to obtain at least one signal-to-noise ratio;

and combining M vectors corresponding to the maximum signal-to-noise ratio or M linear combination backward vectors corresponding to the maximum signal-to-noise ratio into the interference cancellation matrix.

In a fifth implementation manner of the first aspect, with reference to the first implementation manner of the first aspect, before obtaining an interference cancellation matrix according to the channel characteristics and the interference characteristics, the method further includes:

combining the channel characteristics and the interference characteristics into a second joint matrix H';

performing unitary matrix decomposition on the second combined matrix to obtain H' ═ UxSxV; wherein, the U and the V are unitary matrixes, and the S is a diagonal matrix;

and transmitting the V matrix to a transmitting device so that the transmitting device sets a precoding coefficient according to the V matrix.

In a sixth implementation manner of the first aspect, with reference to the fifth implementation manner of the first aspect, the obtaining an interference cancellation matrix according to the channel characteristics and the interference characteristics includes:

and performing conjugate rotation on a matrix formed by the M vectors corresponding to the channel characteristics in the U matrix to serve as the interference cancellation matrix.

In a seventh implementation manner of the first aspect, with reference to any implementation manner of the first aspect to the sixth implementation manner of the first aspect, for any interference feature vector in the interference features, before the acquiring the interference feature vector, the method further includes:

receiving a third signal in a second receiving period;

if the third signal is determined to be an interference signal, recording interference eigenvectors of the third signal on Nr receiving antennas;

the obtaining the interference feature vector comprises:

taking an interference eigenvector of the third signal on Nr receiving antennas as the interference eigenvector; or

The obtaining the interference feature vector comprises:

carrying out weighted summation on the interference eigenvectors of the third signal on the Nr receiving antennas and the interference eigenvectors of the interference signals received in the at least one other receiving period on the Nr receiving antennas;

and recording the result after weighted summation as an interference eigenvector of the third signal on Nr receiving antennas.

In an eighth implementation manner of the first aspect, with reference to the seventh implementation manner of the first aspect, the determining that the third signal is an interference signal includes:

and demodulating the third signal, and if at least one domain of the demodulated data frame is the same as a domain of a preset interference source, determining that the third signal is an interference signal.

In a ninth implementation manner of the first aspect, with reference to the seventh implementation manner of the first aspect, the determining that the third signal is an interference signal includes:

demodulating a domain message SIG corresponding to the third signal; wherein the SIG comprises: data flow information and a check field;

calculating a first check field according to a preset algorithm, and if the first check field is different from the check field contained in the SIG, determining that the third signal is an interference signal;

or, if the data format of the data stream information is different from a preset data format, determining that the third signal is an interference signal.

In a tenth implementable manner of the first aspect, with reference to any one of the first implementable manner of the first aspect to the ninth implementable manner of the first aspect, before multiplying the interference cancellation matrix with the first signal, the method further comprises:

calculating the correlation degree of each interference characteristic vector in the interference matrix and each row vector or column vector of the channel characteristics of the channel for transmitting the first signal;

determining whether a correlation degree of each interference feature vector of the interference matrix with each row vector or column vector of channel features of a channel transmitting the first signal is less than a second preset threshold value;

the multiplying the interference cancellation matrix by the first signal specifically includes:

and if the interference cancellation matrix is smaller than a second preset threshold value, multiplying the interference cancellation matrix by the first signal.

In an eleventh implementation manner of the first aspect, with reference to the tenth implementation manner of the first aspect, before estimating, from the second signal, a channel characteristic of the second signal, the method further includes:

receiving the second signal with a pre-stored first interference cancellation vector to cancel interference in the second signal;

determining whether the signal energy of the received second signal is greater than or equal to a third preset threshold value;

the estimating and sending the channel characteristic of the second signal according to the second signal specifically includes:

and if the second signal is greater than or equal to the third preset threshold, estimating and sending the channel characteristics of the second signal according to the second signal.

In a second aspect, an embodiment of the present invention provides a receiving device, where the receiving device is configured with Nr receiving antennas, and is configured to receive signals output by Nt transmitting antennas or spatial streams or spatial-temporal streams, where Nr is an integer greater than or equal to 2; nt is an integer greater than or equal to 1; the method comprises the following steps:

a receiving unit for receiving a first signal; the first signal comprises signals and noise signals which are obtained after signals output by Nt sending antennas or space streams or space time streams received by Nr receiving antennas pass through a channel;

an obtaining unit, configured to obtain an interference cancellation matrix; the interference cancellation matrix comprises M interference cancellation vectors, each interference cancellation vector comprises Nr interference cancellation coefficients, and the correlation degree between each interference cancellation vector and an interference characteristic vector of any interference source in N interference sources on Nr receiving antennas is smaller than a first preset threshold value; m is the number of preset interference cancellation vectors; n is the number of preset interferences;

and the interference cancellation unit is used for multiplying the interference cancellation matrix and the first signal and demodulating the multiplied signal to obtain a data stream.

In a first implementable manner of the second aspect, with reference to the second aspect, the receiving unit is further configured to receive a second signal in a first receiving period, where the second signal is received by Nr receiving antennas;

the receiving apparatus further includes:

a channel estimation unit configured to estimate a channel characteristic of a channel transmitting the second signal according to the second signal received by the reception unit; wherein the channel characteristics are a matrix of Nr times Nt;

the obtaining unit is specifically configured to:

and acquiring an interference cancellation matrix according to the channel characteristics estimated by the channel estimation unit and the acquired interference characteristics.

In a second implementable manner of the second aspect, with reference to the first implementable manner of the second aspect, for any interference cancellation vector in the interference cancellation matrix, the obtaining unit is specifically configured to:

In a third implementable manner of the second aspect, with reference to the first implementable manner of the second aspect, the obtaining unit is specifically configured to:

In a fourth implementation manner of the second aspect, with reference to the third implementation manner of the second aspect, the obtaining unit is specifically configured to:

In a fifth implementable manner of the second aspect, with reference to the first implementable manner of the second aspect, the receiving device further includes:

the decomposition unit is used for combining the channel characteristics estimated by the channel estimation unit and the interference characteristics acquired by the acquisition unit into a second combined matrix H' before the acquisition unit acquires an interference cancellation matrix according to the channel characteristics and the interference characteristics;

and the sending unit is used for sending the V matrix decomposed by the decomposition unit to sending equipment so that the sending equipment sets a precoding coefficient according to the V matrix.

In a sixth implementation manner of the second aspect, with reference to the fifth implementation manner of the second aspect, the obtaining unit is specifically configured to:

In a seventh implementable manner of the second aspect, with reference to any one of the first implementable manner to the sixth implementable manner of the second aspect, for any one of the interference feature vectors, before the obtaining unit obtains the interference feature vector,

the receiving unit is further configured to receive a third signal in a second receiving period;

the obtaining unit is further configured to record an interference eigenvector of the third signal on Nr receiving antennas if it is determined that the third signal received by the receiving unit is an interference signal;

taking an interference feature vector of the third signal on Nr receiving antennas as the interference feature; or

In an eighth implementation manner of the second aspect, with reference to the seventh implementation manner of the second aspect, the obtaining unit is specifically configured to:

In a ninth implementation manner of the second aspect, with reference to the seventh implementation manner of the second aspect, the obtaining unit is specifically configured to:

In a tenth implementable manner of the second aspect, with reference to any one of the first implementable manner to the ninth implementable manner of the second aspect, the receiving device further includes:

a calculating unit, configured to calculate a correlation degree between each interference eigenvector in the interference matrix and each row vector or column vector of channel characteristics of a channel transmitting the first signal before the interference cancellation unit multiplies the interference cancellation matrix by the first signal;

the interference cancellation unit is specifically configured to:

In an eleventh implementation manner of the second aspect, with reference to the tenth implementation manner of the second aspect, the interference cancellation unit is further configured to:

before the channel estimation unit estimates and transmits the channel characteristics of the second signal according to the second signal, receiving the second signal by using a first interference cancellation vector stored in advance so as to cancel interference in the second signal;

the channel estimation unit is specifically configured to:

In a third aspect, an embodiment of the present invention provides a receiving device, where the receiving device is configured with Nr receiving antennas, and is configured to receive signals output by Nt transmitting antennas or spatial streams or spatial-temporal streams, where Nt is an integer greater than or equal to 2, and Nt is an integer greater than or equal to 1; the method comprises the following steps:

a transceiver for receiving a first signal; the first signal comprises signals and noise signals which are obtained after signals output by Nt sending antennas or space streams or space time streams received by Nr receiving antennas pass through a channel;

a processor configured to obtain an interference cancellation matrix; the interference cancellation matrix comprises M interference cancellation vectors, each interference cancellation vector comprises Nr interference cancellation coefficients, and the correlation degree between each interference cancellation vector and an interference characteristic vector of any interference source in N interference sources on Nr receiving antennas is smaller than a first preset threshold value; m is the number of preset interference cancellation vectors; n is the number of preset interferences;

In a first implementable manner of the third aspect, with reference to the third aspect, the transceiver is further configured to receive a second signal in a first reception period, where the second signal is a signal received by Nr reception antennas;

the processor is specifically configured to:

estimating channel characteristics of a channel transmitting a second signal from the second signal received by the transceiver; wherein the channel characteristics are a matrix of Nr times Nt;

and acquiring an interference cancellation matrix according to the channel characteristics estimated by the processor and the acquired interference characteristics.

In a second implementable manner of the third aspect, with reference to the first implementable manner of the third aspect, for any interference cancellation vector in the interference cancellation matrix, the processor is specifically configured to:

In a third implementable manner of the third aspect, with reference to the first implementable manner of the third aspect, the processor is specifically configured to:

In a fourth implementable manner of the third aspect, with reference to the third implementable manner of the third aspect, the processor is specifically configured to:

In a fifth implementable manner of the third aspect, with reference to the first implementable manner of the third aspect, the processor is further configured to:

before the processor acquires an interference cancellation matrix according to the channel characteristics and the interference characteristics, combining the channel characteristics estimated by the processor and the interference characteristics acquired by the processor into a second combined matrix H';

the transceiver is further configured to send the V matrix decomposed by the processor to a sending device, so that the sending device sets a precoding coefficient according to the V matrix.

In a sixth implementable manner of the third aspect, with reference to the fifth implementable manner of the third aspect, the processor is specifically configured to:

In a seventh implementable manner of the third aspect, with reference to any one of the first implementable manner to the sixth implementable manner of the third aspect, for any one of the interference features, before the processor acquires the interference feature vector,

the transceiver is further used for receiving a third signal in a second receiving period;

the processor is further configured to record an interference eigenvector of the third signal on Nr receiving antennas if it is determined that the third signal received by the transceiver is an interference signal;

In an eighth implementable manner of the third aspect, with reference to the seventh implementable manner of the third aspect, the processor is specifically configured to:

In a ninth implementable manner of the third aspect, with reference to the seventh implementable manner of the third aspect, the processor is specifically configured to:

In a tenth implementable manner of the third aspect, with reference to any one of the first implementable manner to the ninth implementable manner of the third aspect,

the processor is further configured to calculate a correlation degree between each interference eigenvector in the interference matrix and each row vector or column vector of channel characteristics of a channel transmitting the first signal before the processor multiplies the interference cancellation matrix with the first signal;

In an eleventh implementation manner of the third aspect, with reference to the tenth implementation manner of the third aspect, the processor is further configured to:

before the processor estimates the channel characteristics of the second signal according to the second signal, receiving the second signal by using a first interference cancellation vector stored in advance so as to cancel the interference in the second signal;

As can be seen from the above, the embodiments of the present invention provide an interference cancellation method and apparatus, where after a first signal is received, an obtained interference cancellation matrix is multiplied by the first signal, and the multiplied signal is demodulated to obtain M data streams, so as to cancel interference in the M data streams, so that the data obtained after demodulation is data after interference cancellation, and reliability of data transmission is greatly improved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a schematic view of a WLAN system channel model;

fig. 2 is a schematic block diagram of interference cancellation provided by an embodiment of the present invention;

fig. 2A is a schematic block diagram of another interference cancellation provided in an embodiment of the present invention;

fig. 3 is a flowchart of an interference cancellation method according to an embodiment of the present invention;

FIG. 4 is a diagram illustrating a signal format in a receiving period according to an embodiment of the present invention;

fig. 5 is a block diagram of a receiving device 50 according to an embodiment of the present invention;

fig. 5A is a block diagram of a receiving device 50 according to an embodiment of the present invention;

fig. 5B is a block diagram of a receiving device 50 according to an embodiment of the present invention;

fig. 5C is a block diagram of a receiving device 50 according to an embodiment of the present invention;

fig. 6 is a block diagram of a receiving device 60 according to an embodiment of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that the interference cancellation method provided in the embodiment of the present invention is not only applicable to the WLAN system, but also applicable to other communication systems that employ multiple antenna receiving technologies.

In a WLAN system, in a general case, a WLAN channel and a channel model are shown in fig. 1, when there are multiple transceiving antennas, a signal between a receiving device and a transmitting device may be transmitted through multiple paths, and in a case where the receiving device is not interfered by an interference source, a signal received by the receiving device may be represented as: then, demodulating the received signal to recover the required data or information; wherein x is a signal transmitted by a transmitting device, and may be an Nt-dimensional vector (x1, x2, …, xNt), where Nt may be the number of transmitting antennas, the number of transmitted spatial streams (space-time streams), or the number of transmitted space-time streams (space-time streams), that is, x is a signal output by Nt antennas, or spatial streams or space-time streams, and xj is a signal output by a jth transmitting antenna, or spatial streams or space-time streams; it should be noted that in the 802.11n series of standards, a spatial stream may be a bit (bit) stream or a modulation symbol stream transmitted in multiple spatial dimensions; the space-time stream may be a stream of modulation symbols resulting from spatial combining and temporary processing of one or more spatial streams; in general, user data may be divided into Nt spatial streams and transmitted on a transmission antenna greater than or equal to Nt, for example, a weak signal is divided into 2 spatial streams, then the 2 spatial streams are subjected to space-time block coding (STBC) processing to become 4 spatial-time stream signals, and then further processed into transmission signals of 4 transmission antennas, and then the transmission signal x may be a signal of 2 spatial streams, a signal of 4 spatial-time streams, or a signal transmitted by 4 transmission antennas.

Where y is the signal received by the receiving device, and may be an Nr-dimensional vector (y1, y2, …, yNr), and yi is the signal received by the ith receiving antenna; n is a noise signal; h is a channel matrix (may also be referred to as a MIMO channel), which is a matrix of Nr times Nt, and may be represented as a matrix of Nr rows and Nt columns, or may be a matrix of Nr columns and Nt rows, which is not limited by the comparison in the embodiment of the present invention, and the embodiment of the present invention is described by taking only a matrix of Nr rows and Nt columns as an example, where H is shown as follows, where Hij is a channel characteristic from a jth transmit antenna or a spatial stream or a spatial-temporal stream to an ith receive antenna:

in the channel model as shown in fig. 1, the interference signal suffered by the receiving device can be represented as: iy is IC.I; wherein, I is an interference signal emitted by an interference source, and may be an N-dimensional vector (I1, I2, …, IN), N is the number of interference sources, and Ij is an interference signal of a jth interference source; iy is the sum of the interference signals experienced by the receiving device, which may be an Nr-dimensional vector (Iy1, Iy2, …, IyNr), Iyi is the sum of the interference signals experienced by the ith receiving antenna; the IC is an interference feature (may also be referred to as an interference channel), and may be represented as a matrix composed of N Nr-dimensional row vectors or column vectors, which is not limited in this embodiment of the present invention, and the embodiment of the present invention is described only by taking as an example a matrix composed of N Nr-dimensional column vectors, where the IC is as follows, where the jth column vector is an interference feature of the jth interference source:

as can be seen from the above, when the signal received by the receiving device is interfered, the received signal can be expressed as: y is H · x + IC · I + n; at this time, if a vector can be obtained, and the modulus of the result after multiplication with each column of vectors of the IC matrix tends to zero or equal to zero as much as possible (in an ideal state), the interference can be reduced to the maximum extent.

Taking an example that a receiving device of IEEE 802.11n series standard shown In fig. 2 acquires a data stream, the receiving device receives a frequency domain signal through amplitude adjustment, In-phase/Quadrature (I/Q) signal detection, Fast Fourier Transform (FFT) processing, and then performs interference cancellation on the signal by using an interference cancellation vector (as shown In a dashed line box In fig. 2), and then performs demodulation processing to obtain a useful data stream; similarly, when the receiving device needs to obtain multiple data streams (as shown in fig. 2A) at the same time, it may use one interference cancellation vector corresponding to each data stream to multiply the signal vector y to perform interference cancellation, obtain cancellation signals of the multiple data streams, and perform demodulation processing to obtain the multiple data streams.

It should be noted that, the present invention may perform interference cancellation on the frequency domain signal, may also perform interference cancellation on the time domain signal, and is not limited to this. Furthermore, the present invention is applicable not only to the receiving device of IEEE 802.11 series standard, but also to the receiving device of other standard (such as bluetooth, LAA), and the interference cancellation principle is the same regardless of the receiving device of any standard. The interference cancellation method provided by the present invention is described below by way of an embodiment.

Example one

Fig. 3 is a flowchart of an interference cancellation method provided in an embodiment of the present invention, which is applied to a receiving device, where the receiving device is configured with Nr receiving antennas, and is configured to receive signals output by Nt transmitting antennas or spatial streams (space streams) or space-time streams (space-time streams), where Nr is an integer greater than or equal to 2, and Nt is an integer greater than or equal to 1; the receiving device may be a workstation device, such as: mobile phones, computers, smart televisions, movie boxes and other equipment; it may also be an access device, such as: wireless router, some Digital Subscriber Line Customer Premise devices (DSL CPE for short), terminal Device (Cable Modem for short), Optical Network Unit (ONU for short), and the like; as shown in fig. 3, the method may include:

301. receiving a first signal; the first signal includes signals and noise signals after signals output by Nt transmitting antennas or spatial streams or space time streams received by Nr receiving antennas pass through channels.

Generally, in a WLAN system, a receiving device may receive at least 2 parts of signals successively in one receiving period: a first partial signal and a second partial signal; the first part of the signal is demodulated to obtain corresponding preamble code words (also called protocol headers) containing multiple purposes, such as indicating the arrival of data, indicating the format of data stream, estimating the channel characteristics, estimating the energy intensity of the received signal, estimating the frequency error and the time error, etc.; the second part of the signal can be demodulated by different demodulation modes to obtain a plurality of data streams.

For example, fig. 4 shows a signal receiving format in one receiving period in the 802.11n series of standards, and as shown in fig. 4, the signal may include: a first partial signal and a second partial signal; wherein, the first part signal can be obtained correspondingly after demodulation: short Training Field (STF), Signal Field (SIG) and Long Training Field (LTF) information, the STF may be used to perform Clear Channel Assessment (CCA) to detect the arrival of a received Signal, the SIG may be used to determine whether a Signal is an interfering Signal, and the LTF may be used to estimate Channel characteristics; the second part of the signal can be demodulated to obtain Data (Data).

Optionally, the first signal may be a second part of signals in any receiving period, multiple data streams may be demodulated, and the multiple data streams may not be interfered by the interference source or may be interfered by the interference source; when the first signal is not interfered by the interference source, the first signal only includes signals and noise signals after signals output by Nt transmitting antennas or spatial streams or space-time streams received by Nr receiving antennas pass through channels, and may be represented as: y is H · x + n; when the first signal is interfered by an interference source, the first signal may further include a composite signal of the interference signal, and may be represented by a signal representation interfered by the interference source under the channel model shown in fig. 1: and y is H · x + IC · I + n, which is not described herein.

302. Acquiring an interference cancellation matrix; the interference cancellation matrix comprises M interference cancellation vectors, each interference cancellation vector comprises Nr interference cancellation coefficients, and the correlation degree between each interference cancellation vector and an interference characteristic vector of any interference source in N interference sources on Nr receiving antennas is smaller than a first preset threshold value; m is the number of preset interference cancellation vectors; and N is the preset number of interferences.

When M is equal to 1, the interference cancellation matrix in step 302 only includes 1 interference cancellation vector, that is, the interference cancellation matrix may be regarded as one interference cancellation vector; the number N of interference sources may be obtained according to statistical measurement of interference conditions of the environment where the receiving device is located, and may be one interference source or multiple interference sources, which is not limited in this embodiment of the present invention.

In this embodiment of the present invention, the correlation between vectors may refer to: the size of the included angle between the vectors can be represented by a cosine value of the included angle of the vectors or an absolute value of the cosine value of the included angle of the vectors; if the correlation degree is close to 0 degree or 180 degrees, the vectors are close to parallel, and the vectors are correlated; if the correlation degree is close to 90 degrees, the vectors are close to vertical, and the vectors are not correlated; in general, the correlation between vectors can be obtained by a common calculation method such as cosine correlation, Pearson product moment (Pearson) correlation coefficient, and the like.

The first preset threshold value can be set as required to tend to zero or equal to zero as much as possible (in an ideal state), and the correlation degree of the interference cancellation vector and each column of the interference feature vectors is smaller than the first preset threshold value: the interference cancellation vector is irrelevant to the interference characteristics corresponding to each interference source, and the interference of the interference source can be cancelled to the maximum extent by using the interference cancellation vector; the correlation degree between the interference cancellation vector and each column of interference feature vectors in the interference features is greater than or equal to a first preset threshold value: there is a certain correlation between the interference cancellation vector and the interference characteristic corresponding to each interference source, and the interference cancellation vector cannot be used to cancel the interference of the interference source.

Optionally, in this embodiment of the present invention, the receiving device may obtain the interference cancellation matrix by the following method:

The second signal is a first part of signals in a first receiving period, and preamble code words used for indicating data arrival, indicating a format of a data stream, estimating channel characteristics, estimating received signal energy intensity, estimating frequency error, time error and the like can be obtained after demodulation, and can be in the first receiving period simultaneously with the first signal or in the first receiving period before the receiving period of the first signal; when the signal is in a first receiving period before the receiving period in which the first signal is located, an interference cancellation vector used for canceling the data stream after the demodulation of the first signal in the interference cancellation matrix is a historically stored interference cancellation vector, instead of an interference cancellation vector obtained according to a channel matrix estimated from the first part of signals received in the receiving period of this time.

Optionally, after receiving the second signal, it is further required to determine whether the second signal is a useful signal according to the demodulated second signal, and if the second signal is a useful signal, obtain the interference cancellation matrix according to the channel characteristic and the obtained interference characteristic according to a channel characteristic of a channel through which the second signal is transmitted; if the second signal is an interference signal, recording the interference characteristic of the second signal, ending the subsequent receiving process in the first receiving period, and monitoring the signal in the next receiving period; the useful signal described in this embodiment is a signal interfered by an interference source, and may include a signal and an interference signal transmitted by a transmitting end, for example, the useful signal y is H · x + IC · I + n; the interference signal is a signal that does not include a signal transmitted by the transmitting end and is only interfered by an interference source, such as an interference signal: y is IC · I.

303. And multiplying the interference cancellation matrix and the first signal, and demodulating the multiplied signal to obtain a data stream.

For example, the estimation of the channel characteristics in step 302 may be performed by using the prior art, and will not be described herein.

For example, for any one of the interference feature vectors, the receiving device may take the interference feature vector of the interference signal recorded in advance as the interference feature vector in the interference feature, and then combine the recorded N interference feature vectors into the interference feature, for example:

the receiving equipment receives a third signal in a second receiving period and judges whether the third signal is an interference signal;

The second receiving period may be any receiving period before the first receiving period.

Specifically, in the embodiment of the present invention, whether the third signal is an interference signal may be determined by any one of the following manners (1), (2), and (3):

(1) and demodulating the third signal, and if at least one domain of the demodulated data frame is the same as a domain of a preset interference source, determining that the third signal is an interference signal.

The data frame may be a physical (MAC) layer frame or a frame of higher-layer service (such as an IP packet); the field may be an address field of a data frame, such as: the domain of the 802.11MAC frame can be a destination address and a source address, and the domain of the IP packet can be any address contained in the IP packet; or an identifier for identifying the WLAN, such as: service Set Identification (SSID), Basic Service Set Identification (BSSID), and so on.

For example, if the domain of the predetermined interferer is a1, the third signal is demodulated to be a MAC frame, and the destination address is a1, then the third signal is determined to be an interferer.

(2) Demodulating a domain message SIG corresponding to the third signal; wherein the first SIG comprises: data flow information and a check field;

The data stream information is necessary for demodulating the signal to obtain the data stream, and includes: modulation and Coding Scheme (MCS), channel bandwidth, use of Space-time block (STBC) technique, Forward Error Correction (FEC) coding method, and the like.

(3) And acquiring the spectral characteristics of the third signal, and determining the third signal as an interference signal if the spectrum of the third signal is matched with the spectral characteristics of a preset interference source.

Optionally, the receiving device may further select, as the interference feature, interference feature vectors corresponding to N different interference sources from a pre-stored interference feature set, where interference feature vectors corresponding to multiple types of interference sources are recorded in the interference feature set, and the interference feature vector corresponding to each type of interference source may be obtained according to interference feature vectors of interference signals recorded multiple times, for example:

and respectively calculating the correlation between the interference characteristic vectors recorded at least once and the interference characteristic vectors of the first type of interference sources, and recording the interference characteristic vectors recorded at least once as the interference characteristic vectors corresponding to the first type of interference sources if the correlation between the interference characteristic vectors recorded each time and the interference characteristic vectors of the first type of interference sources is greater than a preset threshold value.

The preset threshold value can be set according to needs, and the comparison in the embodiment of the invention is not limited; the calculation of the correlation degree may adopt the prior art, and is not described herein again.

In addition, the interference feature set may further include: occupying channel time or signal energy corresponding to each type of interference source; optionally, the selecting, by the receiving device, interference feature vectors corresponding to N different interference sources from a pre-stored interference feature set as the interference features may include:

and the receiving equipment selects the interference characteristic vectors corresponding to the N different interference sources with the longest channel occupying time or the highest signal energy from the pre-stored interference characteristic set as the interference characteristics.

For example, in the embodiment of the present invention, the receiving device may obtain the interference cancellation matrix according to the channel characteristics and the interference characteristics based on any one of (a) an orthogonal method, (b) matrix inversion, and (c) unitary matrix decomposition:

(a) orthogonal method

When the orthogonal method is used to obtain the interference cancellation matrix, one or more interference cancellation vectors may be calculated by using the orthogonal method, and the interference cancellation vectors are combined into the interference cancellation matrix, where the process of obtaining the interference cancellation vectors by using the orthogonal method specifically includes:

Wherein the phase verticality may be approximately close to 90 degrees verticality or completely 90 degrees verticality (in an ideal state); the preset angle can be set as required, and is not described herein again.

(b) Matrix inversion

Wherein the M vectors corresponding to the channel characteristics may be: a vector with the number sequence number of the column (row) equal to the number sequence number of the row (column) where the channel feature corresponding to the data stream needing interference cancellation is located in the channel feature; for example, the number of data streams that need to cancel interference is M, and the data streams that need to cancel interference in the channel matrix correspond to the 2 nd column and the 3 rd column of the first joint matrix, then the vectors in the 2 nd row and the 3 rd row in the inverse matrix are combined to form the interference cancellation matrix.

The linear combination may be to multiply a coefficient with a vector included in the channel matrix, where the coefficient is a scaling factor, and the magnitude of the vector may be adjusted to a certain range, so as to avoid introducing an excessive localization error.

It should be noted that when the number of rows and the number of columns of the first joint matrix are not equal, or the first joint matrix is not of a full rank, performing matrix inversion operation on the first joint matrix may be performing pseudo-inversion on the first joint matrix.

In addition, in order to avoid that the amplitude of the obtained interference cancellation matrix is too large, in the embodiment of the present invention, multiple approximate inversions may be performed on the first joint matrix, and a first M row vector meeting requirements is selected as the interference cancellation matrix, which is specifically as follows:

For example: adding the interference characteristics to the column behind the channel matrix to form a joint matrix H':

it should be noted that, in the embodiment of the present invention, the interference characteristic may be added to a column behind the joint channel matrix, or may be added to a column in front of the joint channel matrix; (H1i, H2i, …, HNri) is the channel signature for the ith data stream and (IC1i, IC2i, …, ICNri) is the interference signature for the ith interfering source.

Then, inverting H' yields:

if the interference in the previous M data streams needs to be counteracted, taking an inverse matrix H'^-1The middle-front M row vectors are used as an interference cancellation matrix C to cancel interference in M data streams or an inverse matrix H'^-1Multiplying the M middle and front row vectors by a coefficient D to obtain an interference cancellation matrix C:

wherein D is a diagonal matrix and is a scaling factor, and the amplitude of C can be adjusted to a certain range, so that an overlarge fixed-point error is avoided.

In addition, when the number of rows and columns of the H 'matrix is not equal, or the H' matrix is not full rank, the H 'matrix can be processed'_LAnd (5) calculating the pseudo inverse.

Furthermore, to avoid too large amplitude of the interference cancellation matrix, H 'may be paired'^-1Performing multiple approximate inversions, and selecting an interference cancellation matrix meeting the requirement from the multiple inversions, specifically as follows:

to H'^-1Carrying out at least one approximate inversion on the matrix to obtain at least one approximate inverse matrix H'^-1；

Respectively utilizing the at least one containing approximate inverse matrix H'^-1Calculating the signal-to-noise ratio of the received signal by using the interference cancellation matrix of the M middle and front row vectors;

and taking the interference cancellation matrix corresponding to the maximum signal-to-noise ratio as an interference cancellation matrix C.

Preferably, when a plurality of data streams are received, the signal-to-noise ratio SNR of the signal can be calculated according to the following formula:

wherein diag represents the diagonal of the matrix, x is the sending signal, diag (C.H). x is the useful signal after the interference is cancelled, and non-diag (C.H). x is the interference between the useful signals; sumByRow represents the sum by row, sumByRow (C · IC + C · BNG) is the interference source and the noise, and BNG is the background noise amplitude received by each antenna in the system.

(c) Unitary matrix decomposition

and transmitting the V matrix to the transmitting equipment so that the transmitting equipment sets a precoding coefficient according to the V matrix.

Optionally, the U matrix and a matrix of M vector combinations corresponding to the channel characteristics are subjected to conjugate rotation and then used as the interference cancellation matrix.

Wherein the M vectors corresponding to the channel characteristics may be: a vector with the number sequence number of the column (row) equal to the number sequence number of the row (column) where the channel feature corresponding to the data stream needing interference cancellation is located in the channel feature; the unitary matrix decomposition may be any of Singular Value Decomposition (SVD), Geometric Mean Decomposition (GMD), and other decomposition methods.

Then, performing unitary matrix decomposition on the H 'to obtain H' ═ UxSxV; wherein, the U and the V are unitary matrixes, and the S is a diagonal matrix;

transmitting the V matrix to a transmitting device so that the transmitting device sets a precoding coefficient according to the V matrix;

and if the interference in the first M data streams needs to be counteracted, performing conjugate rotation on a matrix formed by the first M column vectors of the U matrix and then taking the matrix as the interference counteraction matrix.

Further, in order to avoid attenuating useful data in a signal while cancelling interference in the signal, in an embodiment of the present invention, before multiplying the interference cancellation matrix by the first signal, the method further includes:

The second preset threshold value can be set according to needs, the comparison is not limited in the embodiment of the invention, and if the correlation degree is smaller than the second preset threshold value, the interference characteristic of the interference source is not correlated with the channel matrix, so that the strength of the useful signal is not obviously weakened while the interference in the signal is counteracted by the interference counteraction vector; and if the correlation degree is greater than or equal to a second preset threshold, the correlation degree indicates that the interference characteristics of the interference source are correlated with the channel matrix, the strength of a useful signal in the signal can be weakened while the interference in the signal is counteracted by using an interference cancellation vector, and the interference cancellation matrix cannot be used for multiplying the first signal.

Further, in a general case, when receiving the first part of signals in each receiving period, Clear Channel Assessment (CCA) needs to be performed on a Channel for transmitting the signals, and if the Channel is a busy Channel, the received first part of signals is demodulated to obtain SIG for estimating Channel characteristics and determining whether the signals are useful signals; if the channel is an idle channel, no processing is performed;

however, in a certain situation, when the sending device does not send a signal, the receiving device receives interference and the received energy is greater than the threshold (which is equivalent to the channel being completely occupied by the interference), the receiving device may misunderstand that the channel is busy, and in order to avoid that the receiving device misunderstands the channel occupied by the interference as a busy channel in which the sending device is transmitting a signal, in the embodiment of the present invention, interference cancellation may be performed on the received first part of signals, for example, taking the second signal as an example, performing interference cancellation on the received second signal:

if the channel is larger than or equal to the third preset threshold, determining that the channel is busy, and estimating and sending the channel characteristics of the second signal according to the second signal; and if the signal energy of the first signal after the interference cancellation is determined to be less than the third preset threshold, determining that the channel is idle, and sending data to the sending device by using the channel.

As can be seen from the above, the embodiment of the present invention provides an interference cancellation method, where after a first signal is received, an obtained interference cancellation matrix is multiplied by the first signal, and the multiplied signal is demodulated to obtain M data streams, so as to cancel interference in the M data streams, so that the data obtained after demodulation is data after interference cancellation, and reliability of data transmission is greatly improved.

Example two

Fig. 5 is a block diagram of a receiving device 50 according to an embodiment of the present invention, which is applied to perform the interference cancellation method according to the first embodiment, where the receiving device is configured with Nr receiving antennas, and is configured to receive Nt transmitting antennas or signals output by space streams (space-time streams) or space-time streams (space-time streams), where Nr is an integer greater than or equal to 2; the Nr is an integer greater than or equal to 2, and the Nt is an integer greater than or equal to 1; the apparatus may include:

a receiving unit 501, configured to receive a first signal; the first signal includes signals and noise signals after signals output by Nt transmitting antennas or spatial streams or space time streams received by Nr receiving antennas pass through channels.

An obtaining unit 502, configured to obtain an interference cancellation matrix; the interference cancellation matrix comprises M interference cancellation vectors, each interference cancellation vector comprises Nr interference cancellation coefficients, and the correlation degree between each interference cancellation vector and an interference characteristic vector of any interference source in N interference sources on Nr receiving antennas is smaller than a first preset threshold value; m is the number of preset interference cancellation vectors; and N is the preset number of interferences.

An interference cancellation unit 503, configured to multiply the interference cancellation matrix obtained by the obtaining unit by the first signal received by the receiving unit, and demodulate the multiplied signal to obtain a data stream.

Further, in order to obtain the interference cancellation matrix, on the basis of fig. 5, referring to fig. 5A, the receiving apparatus 50 may further include: a channel estimation unit 504;

the receiving unit 501 is further configured to receive a second signal in a first receiving period, where the second signal is a signal received by Nr receiving antennas;

the channel estimation unit 504 is configured to estimate, according to the second signal received by the receiving unit, a channel characteristic of a channel through which the second signal is transmitted; wherein the channel characteristics are a matrix of Nr times Nt;

the obtaining unit 502 is specifically configured to:

Optionally, after the receiving unit 501 receives the second signal, the obtaining unit 502 further needs to determine whether the second signal is a useful signal according to the demodulated second signal, and if the second signal is a useful signal, obtain the interference cancellation matrix according to the channel characteristic and the obtained interference characteristic according to a channel characteristic of a channel for transmitting the second signal; if the second signal is an interference signal, recording the interference characteristic of the second signal, ending the subsequent receiving process in the first receiving period, and monitoring the signal in the next receiving period; the useful signal described in this embodiment is a signal interfered by an interference source, and may include a signal and an interference signal transmitted by a transmitting end, for example, the useful signal y is H · x + IC · I + n; the interference signal is a signal that does not include a signal transmitted by the transmitting end and is only interfered by an interference source, such as an interference signal: y is IC · I.

The channel estimation unit 504 may estimate the channel characteristics by using the prior art, which is not described herein again.

Further, the obtaining unit 502 may use an interference feature vector of an interference signal recorded in advance as an interference feature vector in the interference feature, specifically as follows:

the receiving unit 501 is further configured to receive a third signal in a second receiving period;

the obtaining unit 502 is specifically configured to determine whether the third signal is an interference signal;

Specifically, the acquiring unit 502 may determine whether the third signal is an interference signal by any one of the following manners (1), (2), and (3):

The data stream information is necessary for demodulating the signal to obtain the data stream, and includes: modulation and Coding Scheme (MCS), channel bandwidth, use of Space-time block Coding (STBC) technique, Forward Error Correction (FEC) Coding method, and the like.

Further, the obtaining unit 502 may obtain the interference cancellation matrix according to the channel characteristic and the interference characteristic based on any one of (a) an orthogonal method, (b) matrix inversion, and (c) unitary matrix decomposition:

(a) orthogonal method

When the orthogonal method is used to obtain the interference cancellation matrix, the obtaining unit 502 may calculate one or more interference cancellation vectors by using the orthogonal method, and combine the interference cancellation vectors into the interference cancellation matrix, which is specifically as follows:

(b) Matrix inversion

The obtaining unit 502 is specifically configured to:

In addition, in order to avoid that the amplitude of the obtained interference cancellation matrix is too large, in the embodiment of the present invention, the obtaining unit 502 may further perform multiple approximate inversions on the first joint matrix, and select one first M row vector that meets the requirement as the interference cancellation matrix, which is specifically as follows:

Then, inverting H' yields:

Furthermore, to avoid too large amplitude of the interference cancellation matrix, pair H'^-1Performing multiple approximate inversions, and selecting an interference cancellation matrix meeting the requirement from the multiple inversions, specifically as follows:

(c) Unitary matrix decomposition

Further, in order to obtain the interference cancellation matrix by using unitary matrix decomposition, on the basis of fig. 5A, referring to fig. 5B, the receiving apparatus may further include: decomposition unit 505, transmission unit 506;

the decomposition unit 505 is configured to combine the channel characteristics estimated by the channel estimation unit 504 and the interference characteristics acquired by the acquisition unit 502 into a second association matrix H';

the sending unit 506 is configured to send the V matrix decomposed by the decomposing unit 505 to a sending device, so that the sending device sets a precoding coefficient according to the V matrix.

The obtaining unit 502 is specifically configured to:

and performing conjugate rotation on the U matrix and a matrix of M vector combinations corresponding to the channel characteristics to serve as the interference cancellation matrix.

In this way, the receiving device can cancel the interference in the multiple data streams by using the obtained interference cancellation matrix, thereby providing reliability of data transmission.

Further, in this embodiment of the present invention, in order to avoid attenuating useful data in the signal while canceling interference in the signal, on the basis of fig. 5A, referring to fig. 5C, the receiving apparatus may further include: a calculation unit 507;

the channel estimation unit 504 is further configured to estimate a channel characteristic of a channel in which the first signal is transmitted;

the calculating unit 507 is configured to calculate a correlation degree between each interference eigenvector in the interference matrix and each row vector or column vector of channel characteristics of a channel transmitting the first signal before the interference cancellation unit 503 multiplies the interference cancellation matrix by the first signal;

the interference cancellation unit 503 is specifically configured to:

In general, when receiving the first part of signals in each receiving period, Clear Channel Assessment (CCA) needs to be performed on a Channel for transmitting signals, and if the Channel is a busy Channel, the received first part of signals is demodulated to obtain SIG for estimating Channel characteristics and determining whether the signals are useful signals; if the channel is an idle channel, no processing is performed;

however, in a certain situation, when the sending device does not send a signal, and the receiving device receives interference and the receiving energy is greater than the threshold (which is equivalent to the channel being completely occupied by the interference), the receiving device may misunderstand that the channel is busy, and in order to avoid that the receiving device misunderstands the channel occupied by the interference as a busy channel in which the sending device is transmitting a signal, in this embodiment of the present invention, the interference cancellation unit 503 is further configured to:

before the channel estimation unit 504 estimates the channel characteristics of the second signal according to the second signal, receiving the second signal by using a pre-stored first interference cancellation vector to cancel interference in the second signal;

the channel estimation unit 504 is specifically configured to:

As can be seen from the above, the embodiment of the present invention provides a receiving device, which multiplies a first signal by an obtained interference cancellation matrix after receiving the first signal, and demodulates the multiplied signal to obtain M data streams to cancel interference in the M data streams, so that the data obtained after demodulation is the data after canceling the interference, thereby greatly improving reliability of data transmission.

EXAMPLE III

Fig. 6 shows a structural diagram of a receiving device 60 according to an embodiment of the present invention, which is applied to execute the interference cancellation method according to the first embodiment, as shown in fig. 6, the device may include: a transceiver 601, a processor 602, a memory 603, at least one communication bus 604 for enabling connection and intercommunication among these devices;

a transceiver 601, which may be configured with Nr receiving antennas, configured to receive Nt transmitting antennas or signals output by a space stream (space-time stream) or a space-time stream (space-time stream), where Nr is an integer greater than or equal to 2; nt is an integer greater than or equal to 1; for data transmission with external network elements.

The processor 602 may be a Central Processing Unit (CPU).

The memory 603 may be a volatile memory (RAM), such as a random-access memory (RAM); or a non-volatile memory (english: non-volatile memory), such as a read-only memory (ROM), a flash memory (flash memory), a hard disk (HDD) or a solid-state drive (SSD); or a combination of the above types of memories and provides instructions and data to the processor 602.

A transceiver 601 for receiving a first signal; the first signal includes signals and noise signals after signals output by Nt transmitting antennas or spatial streams or space time streams received by Nr receiving antennas pass through channels.

A processor 602 configured to obtain an interference cancellation matrix; the interference cancellation matrix comprises M interference cancellation vectors, each interference cancellation vector comprises Nr interference cancellation coefficients, and the correlation degree between each interference cancellation vector and an interference characteristic vector of any interference source in N interference sources on Nr receiving antennas is smaller than a first preset threshold value; m is the number of preset interference cancellation vectors; and N is the preset number of interferences.

And multiplying the interference cancellation matrix acquired by the acquisition unit by the first signal received by the receiving unit to acquire M signals, and demodulating the M signals to acquire M data streams.

Further, the transceiver 601 is further configured to receive a second signal in a first receiving period, where the second signal is received by Nr receiving antennas;

the processor 602 is specifically configured to:

estimating channel characteristics of a channel transmitting the second signal according to the second signal received by the receiving unit; wherein the channel characteristics are a matrix of Nr times Nt;

obtaining interference characteristics, wherein the interference characteristics consist of N vectors, the N is the number of interference sources, and the ith vector is an interference characteristic vector of the ith interference source on the Nr receiving antennas;

acquiring an interference cancellation matrix according to the channel characteristics estimated by the channel estimation unit and the acquired interference characteristics; and the correlation degree of each interference cancellation vector in the interference cancellation matrix and each interference characteristic vector in the interference characteristics is smaller than a first preset threshold value.

The processor 602 may estimate the channel characteristics by using the prior art, which is not described herein again.

Further, the processor 602 may use a pre-recorded interference feature vector of the interference signal as an interference feature vector in the interference feature, specifically as follows:

the transceiver 601 is further configured to receive a third signal in a second receiving period;

the processor 602 is specifically configured to determine whether the third signal is an interference signal;

Specifically, the processor 602 may determine whether the third signal is an interference signal by any one of the following manners (1), (2), and (3):

In addition, the interference feature set may further include: occupying channel time or signal energy corresponding to each type of interference source; optionally, the receiving device may further select, as the interference feature, an interference feature vector corresponding to N different interference sources from a pre-stored interference feature set, where the interference feature vector is specifically as follows:

Further, the processor 602 may obtain the interference cancellation matrix according to the channel characteristics and the interference characteristics based on any one of (a) an orthogonal method, (b) matrix inversion, and (c) unitary matrix decomposition:

(a) orthogonal method

When the interference cancellation matrix is obtained by using an orthogonal method, the processor 602 may calculate one or more interference cancellation vectors by using the orthogonal method, and combine the interference cancellation vectors into the interference cancellation matrix, which is as follows:

(b) Matrix inversion

The processor 602 is specifically configured to:

In addition, in order to avoid that the amplitude of the obtained interference cancellation matrix is too large, in the embodiment of the present invention, the processor 602 may further perform multiple approximate inversions on the first joint matrix, and select one first M row vector that meets the requirement as the interference cancellation matrix, which is specifically as follows:

Then, inverting H' yields:

(c) Unitary matrix decomposition

A processor 602, configured to combine the channel characteristics estimated by the processor 602 and the interference characteristics obtained by the processor 602 into a second joint matrix H';

a transceiver 601, configured to send the V matrix decomposed by the processor 602 to a sending device, so that the sending device sets a precoding coefficient according to the V matrix.

The processor 602 is specifically configured to:

Further, in order to avoid attenuating useful data in the signal while canceling interference in the signal, in an embodiment of the present invention, the processor 602 is further configured to:

calculating a correlation of each interference eigenvector in the interference matrix with each row vector or column vector of channel characteristics of a channel transmitting the first signal before the processor 602 multiplies the interference cancellation matrix with the first signal;

the processor 602 is specifically configured to:

The second preset threshold value can be set according to needs, the comparison is not limited in the embodiment of the invention, and if the correlation degree is smaller than the second preset threshold value, the interference characteristic of the interference source is not correlated with the channel matrix, so that the strength of the useful signal is not obviously weakened while the interference in the signal is counteracted by the interference counteraction vector;

and if the correlation degree is greater than or equal to a second preset threshold, the correlation degree indicates that the interference characteristics of the interference source are correlated with the channel matrix, the strength of a useful signal in the signal can be weakened while the interference in the signal is counteracted by using an interference cancellation vector, and the interference cancellation matrix cannot be used for multiplying the first signal.

however, in a certain situation, under the condition that the sending device does not send a signal, the receiving device receives interference and the receiving energy is greater than the threshold (which is equivalent to the channel being completely occupied by the interference), the receiving device may misunderstand that the channel is busy, and in order to avoid that the receiving device misunderstands the channel occupied by the interference as a busy channel on which the sending device is transmitting a signal, in the embodiment of the present invention, the processor 602 is further configured to:

before the processor 602 estimates channel characteristics of the second signal to be transmitted according to the second signal, receiving the second signal by using a pre-stored first interference cancellation vector to cancel interference in the second signal;

the processor 602 is specifically configured to:

if the channel is larger than or equal to the third preset threshold, determining that the channel is busy, and estimating and sending the channel characteristics of the second signal according to the second signal;

and if the signal energy of the first signal after the interference cancellation is determined to be less than the third preset threshold, determining that the channel is idle, and sending data to the sending device by using the channel.

It is clear to those skilled in the art that, for convenience and brevity of description, the specific working processes of the above-described systems, apparatuses and units may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.

In the several embodiments provided in the present application, it should be understood that the disclosed system, apparatus and method may be implemented in other manners. For example, the above-described apparatus embodiments are merely illustrative, and for example, the division of the units is only one logical division, and other divisions may be realized in practice, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection of some interfaces, devices or units, and may be an electric or other form.

The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.

In addition, functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may be physically included alone, or two or more units may be integrated into one unit. The integrated unit can be realized in a form of hardware, or in a form of hardware plus a software functional unit.

The integrated unit implemented in the form of a software functional unit may be stored in a computer readable storage medium. The software functional unit is stored in a storage medium and includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute some steps of the methods according to the embodiments of the present invention. And the aforementioned storage medium includes: various media capable of storing program codes, such as a usb disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk, or an optical disk.

Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims

An interference cancellation method is applied to a receiving device, where the receiving device is configured with Nr receiving antennas, and is configured to receive signals output by Nt transmitting antennas or spatial streams or space-time streams, where Nr is an integer greater than or equal to 2, and Nt is an integer greater than or equal to 1; the method comprises the following steps:

receiving a first signal; the first signal comprises signals and noise signals which are obtained after signals output by Nt sending antennas or space streams or space time streams received by Nr receiving antennas pass through a channel;

acquiring an interference cancellation matrix; the interference cancellation matrix comprises M interference cancellation vectors, each interference cancellation vector comprises Nr interference cancellation coefficients, and the correlation degree between each interference cancellation vector and an interference characteristic vector of any interference source in N interference sources on Nr receiving antennas is smaller than a first preset threshold value; m is the number of preset interference cancellation vectors; n is the number of preset interferences;

and multiplying the interference cancellation matrix and the first signal, and demodulating the multiplied signal to obtain a data stream.
The interference cancellation method according to claim 1, wherein said obtaining an interference cancellation matrix comprises:

receiving a second signal in a first receiving period, wherein the second signal is a signal received by Nr receiving antennas;

estimating channel characteristics of a channel transmitting the second signal from the second signal; wherein the channel characteristics are a matrix of Nr times Nt;

obtaining interference characteristics, wherein the interference characteristics consist of N vectors, and the ith vector is an interference characteristic vector of the ith interference source on the Nr receiving antennas;

and acquiring the interference cancellation matrix according to the channel characteristics and the interference characteristics.
The interference cancellation method of claim 2, wherein for any interference cancellation vector in the interference cancellation matrix, said obtaining an interference cancellation vector according to the channel characteristic and the interference characteristic comprises:

and acquiring one characteristic vector which is perpendicular to an interference characteristic vector in the interference characteristics and has the minimum included angle with the channel characteristics or the characteristic vector which has the included angle with the channel characteristics smaller than a preset angle as the interference offset vector.
The interference cancellation method of claim 2, wherein the obtaining an interference cancellation matrix according to the channel characteristics and the interference characteristics comprises:

combining the channel characteristics and the interference characteristics into a first joint matrix;

performing matrix inversion operation on the first combined matrix to obtain an inverse matrix;

and combining M vectors corresponding to the channel characteristics in the inverse matrix or M vectors subjected to linear combination corresponding to the channel characteristics into the interference cancellation matrix.
The interference cancellation method of claim 4, wherein performing a matrix inversion operation on the first joint matrix to obtain an inverse matrix comprises:

carrying out approximate inversion at least once on the first combined matrix to obtain at least one approximate inverse matrix;

the combining M vectors corresponding to the channel characteristics in the inverse matrix or M linearly combined vectors corresponding to the channel characteristics into the interference cancellation matrix comprises:

respectively calculating the signal-to-noise ratio of the first signal by using M vectors corresponding to the channel characteristics in the at least one approximate inverse matrix to obtain at least one signal-to-noise ratio;

and combining M vectors corresponding to the maximum signal-to-noise ratio or M linear combination backward vectors corresponding to the maximum signal-to-noise ratio into the interference cancellation matrix.
The interference cancellation method according to claim 2, wherein before obtaining an interference cancellation matrix according to the channel characteristics and the interference characteristics, the method further comprises:

combining the channel characteristics and the interference characteristics into a second joint matrix H';

performing unitary matrix decomposition on the second combined matrix to obtain H' ═ UxSxV; wherein, the U and the V are unitary matrixes, and the S is a diagonal matrix;

and transmitting the V matrix to a transmitting device so that the transmitting device sets a precoding coefficient according to the V matrix.
The interference cancellation method of claim 6, wherein said obtaining an interference cancellation matrix according to the channel characteristics and the interference characteristics comprises:

and performing conjugate rotation on a matrix formed by the M vectors corresponding to the channel characteristics in the U matrix to serve as the interference cancellation matrix.
The interference cancellation method according to any one of claims 2 to 7, wherein for any one of said interference eigenvectors, before said obtaining said interference eigenvector, said method further comprises:

receiving a third signal in a second receiving period;

if the third signal is determined to be an interference signal, recording interference eigenvectors of the third signal on Nr receiving antennas;

the obtaining the interference feature vector comprises:

taking an interference eigenvector of the third signal on Nr receiving antennas as the interference eigenvector; or

The obtaining the interference feature vector comprises:

carrying out weighted summation on the interference eigenvectors of the third signal on the Nr receiving antennas and the interference eigenvectors of the interference signals received in the at least one other receiving period on the Nr receiving antennas;

and recording the result after weighted summation as an interference eigenvector of the third signal on Nr receiving antennas.
The method of claim 8, wherein the determining the third signal as an interfering signal comprises:

and demodulating the third signal, and if at least one domain of the demodulated data frame is the same as a domain of a preset interference source, determining that the third signal is an interference signal.
The method of claim 8, wherein the determining the third signal as an interfering signal comprises:

demodulating a domain message SIG corresponding to the third signal; wherein the SIG comprises: data flow information and a check field;

calculating a first check field according to a preset algorithm, and if the first check field is different from the check field contained in the SIG, determining that the third signal is an interference signal;

or, if the data format of the data stream information is different from a preset data format, determining that the third signal is an interference signal.
The interference cancellation method according to any one of claims 2 to 10, wherein before multiplying said interference cancellation matrix with said first signal, said method further comprises:

calculating the correlation degree of each interference characteristic vector in the interference matrix and each row vector or column vector of the channel characteristics of the channel for transmitting the first signal;

determining whether a correlation degree of each interference feature vector of the interference matrix with each row vector or column vector of channel features of a channel transmitting the first signal is less than a second preset threshold value;

the multiplying the interference cancellation matrix by the first signal specifically includes:

and if the interference cancellation matrix is smaller than a second preset threshold value, multiplying the interference cancellation matrix by the first signal.
The interference cancellation method of claim 11, wherein before estimating channel characteristics of said second signal from said second signal, said method further comprises:

receiving the second signal with a pre-stored first interference cancellation vector to cancel interference in the second signal;

determining whether the signal energy of the received second signal is greater than or equal to a third preset threshold value;

the estimating and sending the channel characteristic of the second signal according to the second signal specifically includes:

and if the second signal is greater than or equal to the third preset threshold, estimating and sending the channel characteristics of the second signal according to the second signal.
A receiving device, where the receiving device is configured with Nr receiving antennas, and is configured to receive signals output by Nt transmitting antennas or spatial streams or spatial-temporal streams, where Nt is an integer greater than or equal to 2, and Nt is an integer greater than or equal to 1; it is characterized by comprising:

a receiving unit for receiving a first signal; the first signal comprises signals and noise signals which are obtained after signals output by Nt sending antennas or space streams or space time streams received by Nr receiving antennas pass through a channel;

an obtaining unit, configured to obtain an interference cancellation matrix; the interference cancellation matrix comprises M interference cancellation vectors, each interference cancellation vector comprises Nr interference cancellation coefficients, and the correlation degree between each interference cancellation vector and an interference characteristic vector of any interference source in N interference sources on Nr receiving antennas is smaller than a first preset threshold value; m is the number of preset interference cancellation vectors; n is the number of preset interferences;

and the interference cancellation unit is used for multiplying the interference cancellation matrix and the first signal and demodulating the multiplied signal to obtain a data stream.
The receiving device of claim 13,

the receiving unit is further configured to receive a second signal in a first receiving period, where the second signal is a signal received by Nr receiving antennas;

the receiving apparatus further includes:

a channel estimation unit configured to estimate a channel characteristic of a channel transmitting the second signal according to the second signal received by the reception unit; wherein the channel characteristics are a matrix of Nr times Nt;

the obtaining unit is specifically configured to:

obtaining interference characteristics, wherein the interference characteristics consist of N vectors, and the ith vector is an interference characteristic vector of the ith interference source on the Nr receiving antennas;

and acquiring an interference cancellation matrix according to the channel characteristics estimated by the channel estimation unit and the acquired interference characteristics.
The receiving device according to claim 14, wherein the obtaining unit is specifically configured to, for any interference cancellation vector in the interference cancellation matrix:

and acquiring one characteristic vector which is perpendicular to an interference characteristic vector in the interference characteristics and has the minimum included angle with the channel characteristics or the characteristic vector which has the included angle with the channel characteristics smaller than a preset angle as the interference offset vector.
The receiving device according to claim 14, wherein the obtaining unit is specifically configured to:

combining the channel characteristics and the interference characteristics into a first joint matrix;

performing matrix inversion operation on the first combined matrix to obtain an inverse matrix;

and combining M vectors corresponding to the channel characteristics in the inverse matrix or M vectors subjected to linear combination corresponding to the channel characteristics into the interference cancellation matrix.
The receiving device according to claim 16, wherein the obtaining unit is specifically configured to:

carrying out approximate inversion at least once on the first combined matrix to obtain at least one approximate inverse matrix;

respectively calculating the signal-to-noise ratio of the first signal by using M vectors corresponding to the channel characteristics in the at least one approximate inverse matrix to obtain at least one signal-to-noise ratio;

and combining M vectors corresponding to the maximum signal-to-noise ratio or M linear combination backward vectors corresponding to the maximum signal-to-noise ratio into the interference cancellation matrix.
The receiving device according to claim 14, wherein the receiving device further comprises:

the decomposition unit is used for combining the channel characteristics estimated by the channel estimation unit and the interference characteristics acquired by the acquisition unit into a second combined matrix H' before the acquisition unit acquires an interference cancellation matrix according to the channel characteristics and the interference characteristics;

performing unitary matrix decomposition on the second combined matrix to obtain H' ═ UxSxV; wherein, the U and the V are unitary matrixes, and the S is a diagonal matrix;

and the sending unit is used for sending the V matrix decomposed by the decomposition unit to sending equipment so that the sending equipment sets a precoding coefficient according to the V matrix.
The receiving device according to claim 18, wherein the obtaining unit is specifically configured to:

and performing conjugate rotation on a matrix formed by the M vectors corresponding to the channel characteristics in the U matrix to serve as the interference cancellation matrix.
The receiving device according to any of claims 14-19, wherein for any of the interference eigenvectors, before the obtaining unit obtains the interference eigenvector,

the receiving unit is further configured to receive a third signal in a second receiving period;

the obtaining unit is further configured to record an interference eigenvector of the third signal on Nr receiving antennas if it is determined that the third signal received by the receiving unit is an interference signal;

taking an interference feature vector of the third signal on Nr receiving antennas as the interference feature; or

Carrying out weighted summation on the interference eigenvectors of the third signal on the Nr receiving antennas and the interference eigenvectors of the interference signals received in the at least one other receiving period on the Nr receiving antennas;

and recording the result after weighted summation as an interference eigenvector of the third signal on Nr receiving antennas.
The receiving device according to claim 20, wherein the obtaining unit is specifically configured to:

and demodulating the third signal, and if at least one domain of the demodulated data frame is the same as a domain of a preset interference source, determining that the third signal is an interference signal.
The receiving device according to claim 20, wherein the obtaining unit is specifically configured to:

demodulating a domain message SIG corresponding to the third signal; wherein the SIG comprises: data flow information and a check field;

calculating a first check field according to a preset algorithm, and if the first check field is different from the check field contained in the SIG, determining that the third signal is an interference signal;

or, if the data format of the data stream information is different from a preset data format, determining that the third signal is an interference signal.
The receiving device according to any one of claims 14 to 22, wherein the receiving device further comprises:

a calculating unit, configured to calculate a correlation degree between each interference eigenvector in the interference matrix and each row vector or column vector of channel characteristics of a channel transmitting the first signal before the interference cancellation unit multiplies the interference cancellation matrix by the first signal;

determining whether a correlation degree of each interference feature vector of the interference matrix with each row vector or column vector of channel features of a channel transmitting the first signal is less than a second preset threshold value;

the interference cancellation unit is specifically configured to:

and if the interference cancellation matrix is smaller than a second preset threshold value, multiplying the interference cancellation matrix by the first signal.
The receiving device of claim 23, wherein the interference cancellation unit is further configured to:

before the channel estimation unit estimates and transmits the channel characteristics of the second signal according to the second signal, receiving the second signal by using a first interference cancellation vector stored in advance so as to cancel interference in the second signal;

determining whether the signal energy of the received second signal is greater than or equal to a third preset threshold value;

the channel estimation unit is specifically configured to:

and if the second signal is greater than or equal to the third preset threshold, estimating and sending the channel characteristics of the second signal according to the second signal.