CN115632915A

CN115632915A - Method and device for eliminating self-interference of full-duplex analog domain

Info

Publication number: CN115632915A
Application number: CN202211153899.1A
Authority: CN
Inventors: 张中山; 张鸿儒; 杜昌澔; 高一凡; 程可辛; 杨杰
Original assignee: Beijing Institute of Technology BIT
Current assignee: Beijing Institute of Technology BIT
Priority date: 2022-09-21
Filing date: 2022-09-21
Publication date: 2023-01-20

Abstract

The invention provides a method and a device for eliminating self-interference in a full-duplex analog domain, comprising the following steps: acquiring a first transmitting signal and a second transmitting signal after the original transmitting signal is separated, wherein the first transmitting signal enters a receiving link after being isolated by a space domain to form a self-interference signal, and the second transmitting signal is input to an interference signal reconstruction unit; based on the optimized input parameters of each vector modulator, respectively carrying out gain and phase adjustment on each reference signal after the second transmitting signal is separated to obtain a cancellation signal for eliminating the self-interference signal; and combining the cancellation signals and the self-interference signals to cancel the self-interference signals. According to the invention, an optimal offset signal is obtained according to the I/Q two-path input parameters of each vector modulator, self-interference elimination in an analog domain is realized through the offset signal, and variable step length iterative optimization is carried out on the I/Q two-path input parameters according to the current optimal parameter direction in the training optimization process, so that the iteration times are reduced and the convergence speed is improved.

Description

Method and device for eliminating self-interference of full-duplex analog domain

Technical Field

The invention relates to the technical field of mobile communication, in particular to a method and a device for eliminating self-interference in a full-duplex analog domain.

Background

With the continuous development of mobile communication technology, mobile data traffic and mobile terminals including internet of things devices all grow explosively, which brings unprecedented pressure to limited spectrum resources, and the existing wireless communication systems usually adopt a time division duplex or frequency division duplex mode, that is, data are transmitted in two ways at different time slots or different frequencies, resulting in that the system capacity is only half of the theoretical limit. The same-frequency simultaneous full-duplex technology supports equipment to bidirectionally transmit data in the same time slot and the same frequency band, and the multiplication of the frequency spectrum efficiency can be realized.

Since two communication parties transmit data in the same frequency and two directions at the same time, the sending device generates strong self-interference to the receiving device, so that the target signal is submerged in the self-interference signal and cannot be demodulated normally, and therefore self-interference elimination is a key challenge for realizing full-duplex communication.

Because the self-interference channel has a time-varying characteristic, when the analog domain self-interference elimination device generates a cancellation signal, a self-adaptive algorithm is needed to be used, and the I/Q two-path input gains of each vector modulator are continuously adjusted according to the change of the environment. The existing self-adaptive algorithm mainly comprises a local searching method and a gradient descent method, however, the local searching method has more searching times; the gradient descent method is difficult to descend due to too small gradient at a position far away from the optimal point, is easy to vibrate due to too large gradient at a position close to the optimal point, is difficult to converge, and is difficult to realize good offset effect and high convergence speed.

Disclosure of Invention

The invention provides a method and a device for eliminating self-interference in a full-duplex analog domain, aiming at improving the convergence rate of iterative optimization of I/Q two-path input parameters of a vector modulator so as to realize better offset effect.

The invention provides a method for eliminating self-interference in a full-duplex analog domain, which comprises the following steps:

acquiring a first transmitting signal and a second transmitting signal after the original transmitting signal is separated, wherein the first transmitting signal enters a receiving link after being subjected to spatial isolation to form a self-interference signal, and the second transmitting signal is input to an interference signal reconstruction unit of a full-duplex analog domain self-interference elimination device;

based on the optimized input parameters corresponding to the vector modulators in the interference signal reconstruction unit, respectively performing gain and phase adjustment on each reference signal after the second transmission signal is separated to obtain a cancellation signal for eliminating the self-interference signal;

the optimized input parameters of each vector modulator are obtained by sequentially carrying out variable step length optimization training on the I path input parameters and the Q path input parameters of each vector modulator according to the optimal parameter direction;

combining the cancellation signal and the self-interference signal to cancel the self-interference signal.

Optionally, before the performing gain and phase adjustment on each reference signal obtained after the second transmission signal is separated based on the optimized input parameter corresponding to each vector modulator in the interference signal reconstruction unit to obtain a cancellation signal for canceling the self-interference signal, the method for canceling the self-interference in the full-duplex analog domain according to the present invention further includes:

acquiring input parameters, search step length and minimum step length of a vector modulator to be optimized;

based on the input parameters, carrying out cancellation processing on the self-interference signal to obtain a residual self-interference signal;

collecting initial output power of the residual self-interference signal;

forming a plurality of mutually different auxiliary input parameters based on the search step length and the input parameters;

based on each auxiliary input parameter, performing cancellation processing on the self-interference signal to obtain an auxiliary residual self-interference signal corresponding to each auxiliary input parameter, so as to acquire auxiliary output power corresponding to each auxiliary residual self-interference signal;

based on the initial output power and each auxiliary output power, carrying out variable step size iterative optimization on the input parameters to obtain optimized input parameters corresponding to the vector modulator to be optimized;

selecting a new vector modulator to be optimized from all the vector modulators except the vector modulator after the optimization is finished; the optimized input parameters corresponding to the optimized vector modulator are kept unchanged;

and returning to execute the steps of obtaining the input parameters, the search step length and the minimum step length of the vector modulator to be optimized until all the vector modulators are optimized, and obtaining the optimized input parameters corresponding to all the vector modulators.

Optionally, according to the method for eliminating self-interference in a full-duplex analog domain provided by the present invention, the step-size-variable iterative optimization is performed on the input parameter based on the initial output power and each of the auxiliary output powers to obtain an optimized input parameter corresponding to the vector modulator to be optimized, where the step-size-variable iterative optimization includes:

comparing the initial output power with each auxiliary output power to judge whether the input parameter is a local optimal parameter based on a comparison result;

if the self-interference signal is not the local optimal parameter, adjusting the input parameters of the vector modulator based on the initial output power and the auxiliary output powers to obtain new input parameters, and returning to execute the step of performing cancellation processing on the self-interference signal based on the input parameters to obtain a residual self-interference signal;

if the vector modulator to be optimized is a local optimal parameter, and the search step length is larger than the minimum step length, the search step length is reduced based on the minimum step length, so that the step of forming a plurality of mutually different auxiliary input parameters based on the search step length and the input parameters is returned to be executed based on a new search step length until the search step length is not larger than the minimum step length, and the optimized input parameters corresponding to the vector modulator to be optimized are obtained.

Optionally, according to the full-duplex analog domain self-interference cancellation method provided by the present invention, the plurality of mutually different auxiliary input parameters include a first auxiliary input parameter, a second auxiliary input parameter, a third auxiliary input parameter, and a fourth step auxiliary parameter; the input parameters comprise I-path input parameters and Q-path input parameters;

forming a plurality of mutually different auxiliary input parameters based on the search step and the input parameters, including:

performing I-path addition on the I-path input parameters and the search step length, and forming first auxiliary input parameters based on a result obtained by the I-path addition and the Q-path input parameters;

performing I path subtraction on the I path input parameters and the search step length, and forming second auxiliary input parameters based on a result obtained by the I path subtraction and the Q path input parameters;

performing Q-path addition on the Q-path input parameters and the search step length, and forming third auxiliary input parameters based on a result obtained by the Q-path addition and the I-path input parameters;

and performing Q path phase subtraction on the Q path input parameters and the search step length, and forming the fourth auxiliary input parameters based on the result obtained by the Q path phase subtraction and the I path input parameters.

Optionally, according to the full-duplex analog domain self-interference cancellation method provided by the present invention, the auxiliary residual self-interference signal includes a first residual self-interference signal, a second residual self-interference signal, a third residual self-interference signal, and a fourth residual self-interference signal; the auxiliary output power comprises a first auxiliary output power, a second auxiliary output power, a third auxiliary output power, and a fourth auxiliary output power;

the canceling the self-interference signal based on each auxiliary input parameter to obtain an auxiliary residual self-interference signal corresponding to each auxiliary input parameter, so as to acquire an auxiliary output power corresponding to each auxiliary residual self-interference signal, includes:

performing cancellation processing on the self-interference signal respectively based on the first auxiliary input parameter, the second auxiliary input parameter, the third auxiliary input parameter and the fourth auxiliary input parameter to obtain a first residual self-interference signal corresponding to the first auxiliary input parameter, a second residual self-interference signal corresponding to the second auxiliary input parameter, a third residual self-interference signal corresponding to the third auxiliary input parameter and a fourth residual self-interference signal corresponding to the fourth auxiliary input parameter;

collecting a first auxiliary output power corresponding to the first residual self-interference signal, a second auxiliary output power corresponding to the second residual self-interference signal, a third auxiliary output power corresponding to the third residual self-interference signal, and a fourth auxiliary output power corresponding to the fourth residual self-interference signal.

Optionally, according to the method for self-interference cancellation in full-duplex analog domain provided by the present invention, the adjusting input parameters of the vector modulator based on the initial output power and each of the auxiliary output powers to obtain new input parameters includes:

if the initial output power is less than or equal to the first auxiliary output power and the initial output power is less than or equal to the second auxiliary output power, keeping the I-path input parameter unchanged;

under the condition that the initial output power is greater than the first auxiliary output power or the initial output power is greater than the second auxiliary output power, if the first auxiliary output power is less than or equal to the second auxiliary output power, adding the I-path input parameter and the search step length to obtain a new I-path input parameter; if the first auxiliary output power is larger than the second auxiliary output power, subtracting the I path input parameter from the search step length to obtain a new I path input parameter;

if the initial output power is less than or equal to the third auxiliary output power and the initial output power is less than or equal to the fourth auxiliary output power, keeping the Q-path input parameters unchanged;

when the initial output power is greater than the third auxiliary output power or the initial output power is greater than the fourth auxiliary output power, if the third auxiliary output power is less than or equal to the fourth auxiliary output power, adding the Q-path input parameters and the search step length to obtain new Q-path input parameters; and if the third auxiliary output power is greater than the fourth auxiliary output power, subtracting the search step length from the Q-path input parameter to obtain a new Q-path input parameter.

Optionally, according to the method for eliminating self-interference in full-duplex analog domain provided by the present invention, the optimized input parameters include an I-path optimized input parameter and a Q-path optimized input parameter;

the performing gain and phase adjustment on each reference signal after the second transmission signal is separated based on the optimized input parameters corresponding to each vector modulator in the interference signal reconstruction unit, to obtain a cancellation signal for canceling the self-interference signal, includes:

separating the second transmitting signals in the interference signal reconstruction unit to obtain a plurality of reference signals;

and respectively adjusting the power and the phase of the reference signal corresponding to each vector modulator based on the I-path optimized input parameter and the Q-path optimized input parameter corresponding to each vector modulator, and combining the adjusted signals at the output unit of the interference signal reconstruction unit to obtain a cancellation signal for eliminating the self-interference signal.

The invention also provides a device for eliminating self-interference in a full-duplex analog domain, which comprises:

the acquisition module is used for acquiring a first transmission signal and a second transmission signal after the separation of an original transmission signal, wherein the first transmission signal enters a receiving link after being subjected to spatial isolation to form a self-interference signal, and the second transmission signal is input to an interference signal reconstruction unit of the full-duplex analog domain self-interference elimination device;

an adjusting module, configured to perform gain and phase adjustment on each reference signal obtained after the second transmit signal is separated based on an optimized input parameter corresponding to each vector modulator in the interference signal reconstruction unit, respectively, to obtain a cancellation signal for eliminating the self-interference signal; the optimized input parameters of each vector modulator are obtained by sequentially carrying out variable step length optimization training on the I-path input parameters and the Q-path input parameters of each vector modulator according to the optimal parameter direction;

a cancellation module, configured to combine the cancellation signal and the self-interference signal to cancel the self-interference signal.

According to the method and the device for eliminating the self-interference in the full-duplex analog domain, the optimal counteracting signal is obtained according to the I/Q two-path input parameters of each vector modulator, the self-interference signal is counteracted through the optimal counteracting signal, the self-interference elimination in the full-duplex analog domain is achieved, the current optimal parameter direction is selected to conduct iterative optimization in the process of training and optimizing the I/Q input parameters of the vector modulators, compared with a traditional local search method, the global search traversal can be avoided, the iteration times are effectively reduced, in the iterative process, the step length is reduced in the process of continuously approaching the optimal point, therefore, compared with a fixed step length greedy search algorithm, the problems that the search precision is limited due to the fact that the step length is too large or the convergence speed is slow due to the fact that the gradient is too small can be solved effectively, compared with a traditional gradient descent method, the problem that the step length is difficult to descend due to the fact that the gradient is too small can be far away from the optimal point can be overcome effectively, and the problem that the oscillation is easily caused by the fact that the gradient is too large can be generated in the position close to the optimal point can be overcome effectively, and the convergence speed can be improved effectively.

Drawings

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

FIG. 1 is a schematic flow chart of a full-duplex analog domain self-interference cancellation method provided by the present invention;

fig. 2 is a schematic structural diagram of a full-duplex analog domain self-interference cancellation apparatus according to an embodiment of the present invention;

FIG. 3 is an internal block diagram of a vector modulator provided by the present invention;

fig. 4 is a flowchart of the working timing of the self-interference reconstruction unit provided in the present invention;

fig. 5 is a schematic diagram of a relationship between I-path input parameters and Q-path input parameters and residual self-interference signal power in the vector modulator according to the embodiment of the present invention;

fig. 6 is a schematic flowchart of variable step size search performed on I-path input parameters and Q-path input parameters of a vector modulator according to an embodiment of the present invention;

fig. 7 is a schematic structural diagram of a full-duplex analog domain self-interference cancellation apparatus provided in the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings, and it is obvious that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be obtained by a person skilled in the art without inventive step based on the embodiments of the present invention, are within the scope of protection of the present invention.

The terminology used in the one or more embodiments of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the one or more embodiments of the invention. As used in one or more embodiments of the present invention, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that the term "and/or" as used in one or more embodiments of the present invention refers to and encompasses any and all possible combinations of one or more of the associated listed items.

It should be understood that, although the terms first, second, etc. may be used herein to describe various information in one or more embodiments of the present invention, such information should not be limited by these terms. These terms are only used to distinguish one type of information from another. For example, a first aspect may be termed a second aspect, and, similarly, a second aspect may be termed a first aspect, without departing from the scope of one or more embodiments of the present invention. The word "if" as used herein may be interpreted as "at" \8230; "or" when 8230; \8230; "or" in response to a determination ", depending on the context.

Exemplary embodiments of the present invention will be described in detail below with reference to fig. 1 to 6.

Fig. 1 is a schematic flow chart of a full-duplex analog domain self-interference cancellation method provided by the present invention. As shown in fig. 1, includes:

step 11, obtaining a first transmitting signal and a second transmitting signal after the original transmitting signal is separated, wherein the first transmitting signal enters a receiving link after being isolated in a spatial domain to form a self-interference signal, and the second transmitting signal is input to an interference signal reconstruction unit of a full-duplex analog domain self-interference elimination device;

it should be noted that fig. 2 is a schematic structural diagram of a full-duplex analog domain self-interference cancellation apparatus provided in an embodiment of the present invention, as shown in fig. 2, the full-duplex analog domain self-interference cancellation apparatus includes a transmitter, a receiver, an interference signal reconstruction unit, a power splitter, a circulator, a combiner, and a power detection device, where the interference signal reconstruction unit includes a plurality of TAP structures connected in parallel, each TAP structure is composed of a radio frequency switch, a time delay, and a vector modulator, the power splitter is used to separate an original transmission signal transmitted by the transmitter, the circulator is used to perform spatial isolation on a transmission link and a reception link to form a self-interference signal, the interference signal reconstruction unit is used to reconstruct a cancellation signal with the same power and opposite phase as the self-interference signal, the combiner is used to cancel the self-interference signal from the cancellation signal, and the power detection device is used to detect the power of a residual interference signal after cancellation.

Specifically, an original transmission signal is obtained by transmitting through a transmitter, and then the original transmission signal is separated by a power divider to form two paths of signals, most of the transmission signal is transmitted through a transmitting antenna (i.e., the first transmission signal in this embodiment), optionally, a circulator is used to perform spatial isolation on a transmitting link and a receiving link, so that the first transmission signal enters the receiving link after spatial isolation to form a self-interference signal, and a small part of the transmission signal (i.e., the second transmission signal in this embodiment) is input to the interference signal reconstruction unit.

Step 12, based on the optimized input parameters corresponding to each vector modulator in the interference signal reconstruction unit, respectively performing gain and phase adjustment on each reference signal after the second transmission signal separation to obtain a cancellation signal for eliminating the self-interference signal;

the optimized input parameters of each vector modulator are obtained by sequentially carrying out variable step length optimization training on the I-path input parameters and the Q-path input parameters of each vector modulator according to the optimal parameter direction;

it should be noted that fig. 3 is an internal structural diagram of the vector modulator provided by the present invention, and as shown in fig. 3, the vector modulator includes two-way modulation of an I-way and a Q-way, where an essential function of the vector modulator is to implement variable gain and variable phase shift on any input radio frequency signal within a limited bandwidth, two I-way and Q-way control signals form a two-dimensional plane, which can be used to define an amplitude of a radio frequency signal gain and a phase of the gain, further, the optimization input parameters include an I-way optimization input parameter and a Q-way optimization input parameter, and the gain and phase adjustment is to adjust power and phase of the signal.

It should be further noted that fig. 4 is a flow chart of a working timing sequence of the self-interference reconstruction unit provided by the present invention, as shown in fig. 4, the working timing sequence of the self-interference reconstruction unit is divided into a training phase and a data transmission phase, where the training phase indicates that the I-path input parameters and the Q-path input parameters of the vector modulators in each tap structure are subjected to step-size-variable search training according to the optimal parameter direction, so as to obtain the I-path optimized input parameters and the Q-path optimized input parameters of each vector modulator in the training phase.

Further, in a data transmission stage, the I-path optimized input parameter and the Q-path optimized input parameter of each vector modulator obtained in the training stage are kept unchanged, and the second transmission signal is separated in the interference signal reconstruction unit to obtain a plurality of reference signals, where each reference signal is input to a corresponding vector modulator, and further, based on the I-path optimized input parameter and the Q-path optimized input parameter corresponding to each vector modulator, the power and the phase of each corresponding reference signal are adjusted, respectively, and the adjusted signals are combined at the output unit of the interference signal reconstruction unit to obtain a cancellation signal for canceling the self-interference signal.

And 13, combining the cancellation signal and the self-interference signal to cancel the self-interference signal.

Specifically, the cancellation signals corresponding to the vector modulators are combined at the output end, and then the combined cancellation signals and the self-interference signals are superimposed in the combiner, so that the self-interference signals are cancelled, and self-interference elimination in a full-duplex analog domain is realized.

According to the embodiment of the invention, through the scheme, self-interference elimination of a full-duplex analog domain is realized, and in the process of training and optimizing I/Q input parameters of a vector modulator, the current optimal parameter direction is selected for iterative optimization, compared with a traditional local search method, global search traversal can be avoided, the iteration times are effectively reduced, and in the iterative process, the step length is reduced in the process of continuously approaching the optimal point, so that compared with a fixed-step greedy search algorithm, the problems of limited search precision due to overlarge step length or low convergence speed due to undersize step length can be solved, compared with a traditional gradient descent method, the problem of difficult descent due to undersize gradient can be effectively overcome at the position far away from the optimal point, the problem of easy oscillation due to overlarge gradient can be effectively overcome at the position near the optimal point, and the convergence speed is effectively improved.

In one embodiment, the step 12: based on the optimized input parameters corresponding to each vector modulator in the interference signal reconstruction unit, respectively performing gain and phase adjustment on each reference signal after the second transmission signal is separated, to obtain a cancellation signal for canceling the self-interference signal, including:

step 121, separating the second transmission signal in the interference signal reconstruction unit to obtain a plurality of reference signals, wherein each reference signal is input to a vector modulator;

and step 122, respectively adjusting the power and the phase of the reference signal corresponding to each vector modulator based on the I-path optimized input parameter and the Q-path optimized input parameter corresponding to each vector modulator, and combining the adjusted signals at the output unit of the interference signal reconstruction unit to obtain a cancellation signal for eliminating the self-interference signal.

It should be noted that, the second transmit signal is separated in the interference signal reconstruction unit to obtain a plurality of reference signals, where each of the reference signals is input to each TAP structure, and then the power and the phase of each corresponding reference signal are adjusted based on the I-path optimized input parameter and the Q-path optimized input parameter corresponding to each vector modulator, so as to obtain the power gain and the phase of the adjusted reference signal, where a relational expression for adjusting the power gain and the phase is:

i＝G cosθ

q＝-Gsinθ

wherein I represents an I-path optimized input parameter, Q represents a Q-path optimized input parameter, G is a power gain of an adjusted reference signal, and θ is a phase of the adjusted reference signal, thereby obtaining adjusted signals output by each vector modulator, wherein the adjusted signals are combined at an output unit of the interference signal reconstruction unit, so as to obtain a cancellation signal for canceling the self-interference signal.

According to the embodiment of the invention, based on the scheme, the I-path input parameter and the Q-path input parameter of the vector modulator are realized, the power and the phase of the corresponding reference signal are adjusted, and the offset signal with the same power and the opposite phase as the self-interference signal is obtained, so that the elimination of the self-interference signal in the analog domain is realized.

In one embodiment, the optimized input parameters corresponding to each vector modulator are obtained based on the following steps:

step 21, obtaining input parameters, search step length and minimum step length of a vector modulator to be optimized, wherein the vector modulator to be optimized is obtained by selecting in each vector modulator;

it should be noted that, a vector modulator in a tap structure that needs to be optimized at present is selected from each parallel tap structure as the vector modulator to be optimized, and the radio frequency switch in the tap structure that needs to be optimized is set to be in an on state, and the radio frequency switches in the other tap structures are set to be in an off state.

It should be further noted that the input parameters include an I-path input parameter and a Q-path input parameter, the I-path input parameter and the Q-path input parameter are preset initialization parameters, and may be specifically set according to an actual situation, and the search step length and the minimum step length may be specifically set according to the actual situation, which is not limited specifically herein.

Step 22, based on the input parameters, performing cancellation processing on the self-interference signal to obtain a residual self-interference signal;

it should be noted that, in the training phase, the first transmit signal and the second transmit signal obtained by separating the original transmit signal through the power divider are separated in the interference signal reconstruction unit to obtain a plurality of reference signals, and the reference signals input to the vector modulator to be optimized may be adjusted by using the input parameters.

Specifically, based on the I-path input parameter and the Q-path input parameter, gain and phase adjustment is performed on a reference signal input into the vector modulator to be optimized, that is, power and phase of the second transmission signal are adjusted to obtain an initial training cancellation signal, and then the initial training cancellation signal and the self-interference signal are combined in a combiner to obtain the residual self-interference signal.

Step 23, collecting initial output power of the residual self-interference signal;

specifically, the initial output power of the residual self-interference signal is collected by a power detection device, for example: assuming that the I input parameter is I and the Q input parameter is Q, the initial output power can be represented as P (I, Q).

Step 24, forming a plurality of mutually different auxiliary input parameters based on the search step length and the input parameters;

specifically, based on the search step length, the I-path input parameter and the Q-path input parameter are adjusted, for example, the search step length is added to the I-path input parameter or subtracted from the I-path input parameter, so as to combine the I-path input parameter and the adjusted Q-path input parameter, and combine the adjusted I-path input parameter and the adjusted Q-path input parameter, so as to form a plurality of mutually different auxiliary input parameters.

Wherein the plurality of mutually different auxiliary input parameters comprise a first auxiliary input parameter, a second auxiliary input parameter, a third auxiliary input parameter and a fourth step auxiliary parameter; the input parameters comprise I-path input parameters and Q-path input parameters; the step 24 includes:

step 241, performing I-way addition on the I-way input parameter and the search step length, and forming the first auxiliary input parameter based on a result obtained by the I-way addition and the Q-way input parameter;

step 242, performing an I-path subtraction on the I-path input parameter and the search step length, and forming the second auxiliary input parameter based on a result obtained by the I-path subtraction and the Q-path input parameter;

step 243, performing Q-path addition on the Q-path input parameters and the search step length, and forming the third auxiliary input parameter based on a result obtained by the Q-path addition and the I-path input parameters;

and 244, performing Q-path subtraction on the Q-path input parameters and the search step length, and forming the fourth auxiliary input parameters based on a result obtained by the Q-path subtraction and the I-path input parameters.

It can be understood that, assuming that the search step is a, the I-path input parameter is I, the Q-path input parameter is Q, the I-path input parameter is I and the search step is a are added, a first auxiliary input parameter (I + a, Q) is formed based on the result I + a obtained by the addition and the Q-path input parameter Q, the I-path input parameter is I and the search step is a are subtracted, a second auxiliary input parameter (I-a, Q) is formed based on the result I-a obtained by the subtraction and the Q-path input parameter Q, the Q-path input parameter is Q and the search step is a are added, a third auxiliary input parameter (I, Q + a) is formed based on the I-path input parameter I and the result Q + a obtained by the addition, a Q-path input parameter is Q and the search step is a are subtracted, and a is formed based on the result Q-a obtained by the subtraction and the I-path input parameter I and the result Q-a obtained by the subtraction.

Step 25, performing cancellation processing on the self-interference signal based on each auxiliary input parameter to obtain an auxiliary residual self-interference signal corresponding to each auxiliary input parameter, so as to acquire auxiliary output power corresponding to each auxiliary residual self-interference signal;

wherein the auxiliary residual self-interference signal comprises a first residual self-interference signal, a second residual self-interference signal, a third residual self-interference signal and a fourth residual self-interference signal; the auxiliary output power comprises a first auxiliary output power, a second auxiliary output power, a third auxiliary output power, and a fourth auxiliary output power; the step 25 includes:

step 251, performing cancellation processing on the self-interference signal respectively based on the first auxiliary input parameter, the second auxiliary input parameter, the third auxiliary input parameter, and the fourth auxiliary input parameter to obtain a first residual self-interference signal corresponding to the first auxiliary input parameter, a second residual self-interference signal corresponding to the second auxiliary input parameter, a third residual self-interference signal corresponding to the third auxiliary input parameter, and a fourth residual self-interference signal corresponding to the fourth auxiliary input parameter;

step 252, collecting a first auxiliary output power corresponding to the first residual self-interference signal, a second auxiliary output power corresponding to the second residual self-interference signal, a third auxiliary output power corresponding to the third residual self-interference signal, and a fourth auxiliary output power corresponding to the fourth residual self-interference signal.

It can be understood that, following the above examples of steps 541 to 544, based on the first auxiliary input parameter (i + a, q), the second auxiliary input parameter (i-a, q), the third auxiliary input parameter (i, q + a), and the fourth auxiliary input parameter (i, q-a), respectively adjusting the power and the phase of the reference signal input to the vector modulator to be optimized, so as to obtain a first cancellation signal corresponding to the first step-length auxiliary input parameter, a second cancellation signal corresponding to the second step-length auxiliary input parameter, a third cancellation signal corresponding to the third step-length auxiliary input parameter, and a fourth cancellation signal corresponding to the fourth step-length auxiliary input parameter;

and superposing the first offset signal, the second offset signal, the third offset signal and the fourth offset signal with the self-interference signal to obtain a first residual self-interference signal corresponding to the first offset signal, a second residual self-interference signal corresponding to the second offset signal, a third residual self-interference signal corresponding to the third offset signal and a fourth residual self-interference signal corresponding to the fourth offset signal, and then acquiring, by a power detection device, first auxiliary output power P (i + a, q) corresponding to the first residual self-interference signal, second auxiliary output power P (i-a, q) corresponding to the second residual self-interference signal, third auxiliary output power P (i, q + a) corresponding to the third residual self-interference signal and fourth auxiliary output power P (i, q-a) corresponding to the fourth residual self-interference signal.

Step 26, based on the initial output power and each auxiliary output power, performing step-size-variable iterative optimization on the input parameters to obtain optimized input parameters corresponding to the vector modulator to be optimized;

specifically, the step of comparing the initial output power and each auxiliary output power, and then determining whether the I-path input parameter and the Q-path input parameter are locally optimal parameters based on the comparison result, if not, adjusting the I-path input parameter and the Q-path input parameter of the vector modulator based on the initial output power and each auxiliary output power to obtain new I-path input parameter and Q-path input parameter, and returning to execute the step of performing cancellation processing on the self-interference signal based on the I-path input parameter and the Q-path input parameter to obtain a residual self-interference signal, so as to optimize the new I-path input parameter and the Q-path input parameter again, and otherwise, if the initial output power is locally optimal and the search step size is greater than the minimum step size, for example, reducing the search step size by one time, returning to execute the step of forming a plurality of mutually different auxiliary input parameters based on the search step size and the input parameter based on the search step size and the new input parameter, until the search step size is not greater than the minimum step size, and obtaining an optimized I-path input parameter and a Q-path input parameter of the vector of the modulator.

Step 27, selecting a new vector modulator to be optimized from the vector modulators except the vector modulator after the optimization; the optimized input parameters corresponding to the optimized vector modulator are kept unchanged; and returning to execute the steps of obtaining the input parameters, the search step length and the minimum step length of the vector modulator to be optimized until all the vector modulators are optimized, and obtaining the optimized input parameters corresponding to all the vector modulators.

Specifically, after the vector modulator to be optimized is optimized, a new vector modulator to be optimized is selected from the vector modulators except the vector modulator subjected to optimization, a radio frequency switch in a tap structure of the new vector modulator to be optimized is turned on, and then the step of obtaining the input parameters, the search step length and the minimum step length of the vector modulator to be optimized is executed in return, so as to perform iterative optimization on the new vector modulator to be optimized, in the process of optimizing the new vector modulator to be optimized, the I-path optimized input parameters and the Q-path optimized input parameters corresponding to the vector modulator subjected to optimization are kept unchanged, the radio frequency switches are kept in an on state, and the radio frequency switches in the tap structures corresponding to the remaining vector modulators are in an off state, at this time, in the process of calculating the residual self-interference signal, gain and phase adjustment is performed on the vector modulator to be optimized currently according to the I-path input parameter and the Q-path input parameter of the vector modulator to be optimized currently, gain and phase adjustment is performed on the reference signal input to the vector modulator to be optimized currently according to the I-path optimized input parameter and the Q-path optimized input parameter corresponding to the vector modulator to be optimized currently, and each adjusted signal is combined at the output end of the interference signal reconstruction unit to obtain a cancellation signal, so that the self-interference signal is subjected to cancellation processing until all the vector modulators are optimized and completed progressively, and the I-path optimized input parameter and the Q-path optimized input parameter corresponding to each vector modulator are obtained.

According to the embodiment of the invention, through the steps, in the process of optimizing the I/Q input parameters of the vector modulator, compared with a traditional local search method, the method can avoid global search traversal, select the current optimal direction for iteration, effectively reduce the iteration times, and reduce the step length in the process of continuously approaching the optimal point in the iteration process, so that compared with a fixed-step greedy search algorithm, the method can solve the problems of limited search precision due to too large step length or low convergence speed due to too small step length, so that the power of the residual self-interference signal can be quickly reduced.

In one embodiment, the step 26: based on the initial output power and each auxiliary output power, performing variable step size iterative optimization on the input parameters to obtain optimized input parameters corresponding to the vector modulator to be optimized, including:

step 261, comparing the initial output power with each auxiliary output power to judge whether the input parameter is a local optimum parameter based on a comparison result;

and 262, if the vector modulator to be optimized is a locally optimal parameter and the search step is larger than the minimum step, narrowing the search step based on the minimum step, and returning to execute a step of forming a plurality of mutually different auxiliary input parameters based on the search step and the input parameters based on a new search step until the search step is not larger than the minimum step to obtain the optimized input parameters corresponding to the vector modulator to be optimized.

Step 263, if the self-interference signal is not the local optimal parameter, adjusting the input parameter of the vector modulator based on the initial output power and each auxiliary output power to obtain a new input parameter, and returning to perform the step of performing cancellation processing on the self-interference signal based on the input parameter to obtain a residual self-interference signal;

wherein, in step 263: adjusting input parameters of the vector modulator based on the initial output power and each of the auxiliary output powers to obtain new input parameters, including:

step 2631, if the initial output power is less than or equal to the first auxiliary output power and the initial output power is less than or equal to the second auxiliary output power, keeping the I-channel input parameter unchanged;

step 2632, in a case that the initial output power is greater than the first auxiliary output power or greater than the second auxiliary output power, if the first auxiliary output power is less than or equal to the second auxiliary output power, subtracting the search step size from the I-path input parameter to obtain a new I-path input parameter; if the first auxiliary output power is larger than the second auxiliary output power, adding the I path input parameter and the search step length to obtain a new I path input parameter;

step 2633, if the initial output power is less than or equal to the third auxiliary output power and the initial output power is less than or equal to the fourth auxiliary output power, keeping the Q-channel input parameter unchanged;

step 2634, in a case that the initial output power is greater than the third auxiliary output power or greater than the fourth auxiliary output power, if the third auxiliary output power is less than or equal to the fourth auxiliary output power, adding the Q-path input parameters and the search step length to obtain new Q-path input parameters; and if the third auxiliary output power is greater than the fourth auxiliary output power, subtracting the search step length from the Q-path input parameter to obtain a new Q-path input parameter.

Specifically, the initial output power is compared with each of the auxiliary output powers, and using the above example, if the initial output power P (I, Q) is less than or equal to the first auxiliary output power P (I + a, Q), the second auxiliary output power P (I-a, Q), the third auxiliary output power P (I, Q + a), and the fourth auxiliary output power P (I, Q-a), it is proved that the current I-path input parameter and Q-path input parameter are local optimal parameters, and then the search step length is compared with the minimum step length, and if the search step length is greater than the minimum step length, the search step length is reduced based on the minimum step length, and preferably, the search step length is reduced by one time, so as to return to execute the step of forming a plurality of auxiliary input parameters different from each other based on the search step length and the input parameter based on the new search step length, until the search step length is not greater than the minimum step length, and obtain the I-path optimized input parameter and the Q-path optimized input parameter of the vector modulator.

Additionally, in the first auxiliary output power P (I + a, Q), the second auxiliary output power P (I-a, Q), the third auxiliary output power P (I, Q + a), and the fourth auxiliary output power P (I, Q-a), if at least one auxiliary output power is smaller than the initial output power, the current I input parameter and Q input parameter are not locally optimal parameters, and further, based on the initial output power and each of the auxiliary output powers, the I input parameter and/or the Q input parameter of the vector modulator are/is adjusted, specifically, the adjusting process is as follows:

adjustment for the I-way input parameter I:

if the initial output power P (I, q) is less than or equal to the first auxiliary output power P (I + a, q) and the initial output power P (I, q) is less than or equal to the second auxiliary output power P (I-a, q), keeping the I-path input parameter I unchanged.

In case the initial output power P (i, q) is greater than the first auxiliary output power P (i + a, q) or the initial output power P (i, q) is greater than the second auxiliary output power P (i-a, q): if the first auxiliary output power P (I + a, q) is less than or equal to a second auxiliary output power P (I-a, q), adding the I-way input parameter I and the search step length a, that is, a new I-way input parameter I = I + a; if the first auxiliary output power P (I + a, q) is greater than the second auxiliary output power P (I-a, q), the I-way input parameter I and the search step length a are subtracted from each other, that is, a new I-way input parameter I = I-a.

Adjustment of Q-way input parameter Q:

if the initial output power P (i, Q) is less than or equal to the third auxiliary output power P (i, Q + a) and the initial output power P (i, Q) is less than or equal to the fourth auxiliary output power P (i, Q-a), keeping the Q-path input parameter Q unchanged.

In case the initial output power P (i, q) is greater than the third auxiliary output power P (i, q + a) or the initial output power P (i, q) is greater than the fourth auxiliary output power P (i, q-a): if the third auxiliary output power P (i, Q + a) is less than or equal to the fourth auxiliary output power P (i, Q-a), adding the Q-path input parameter Q and the search step length a, that is, new Q-path input parameter Q = Q + a; if the third auxiliary output power P (i, Q + a) is greater than the fourth auxiliary output power P (i, Q-a), subtracting the Q-path input parameter Q from the search step length a, that is, subtracting a new Q-path input parameter Q = Q-a.

Further, after new I-path input parameters and Q-path input parameters are obtained, the execution steps are returned to: and performing cancellation processing on the self-interference signal based on the I-path input parameter and the Q-path input parameter to obtain a residual self-interference signal, and performing variable step length iterative optimization on a new I-path input parameter and the Q-path input parameter until an I-path optimized input parameter and a Q-path optimized input parameter of the vector modulator are obtained.

Fig. 5 is a schematic diagram of a relationship between the I-path input parameter and the Q-path input parameter in the vector modulator provided by the embodiment of the present invention and the power of the residual self-interference signal, as shown in fig. 5, in the conventional gradient descent method, the gradient is too small to descend at a position far from the optimal point, and the gradient is too large to oscillate at a position near the optimal point, which makes the algorithm difficult to converge. As shown in fig. 6, fig. 6 is a schematic flow chart of variable step size search for the I-path input parameter and the Q-path input parameter of the vector modulator provided in the embodiment of the present invention, and the initial output power of the current residual self-interference signal is collected by setting the I-path input parameter and the Q-path input parameter, the search step size, and the minimum step size in the vector modulator, and based on the search step size, a plurality of auxiliary output powers adjacent to the initial output power and the plurality of auxiliary output powers are collected, so as to determine whether the I-path input parameter and the Q-path input parameter are local optimal parameters, and thereby perform variable step size iterative optimization on the I-path input parameter and the Q-path input parameter in the vector modulator in the direction of the local optimal parameter, so that the problem that the I-path input parameter and the Q-path input parameter are difficult to drop due to a gradient can be effectively overcome at a position far from the optimal point, and the problem that the I-path input parameter and the Q-path input parameter are easy to generate oscillation due to be too large gradient can be effectively overcome at a position near the optimal point, and the convergence speed can be effectively improved.

The full-duplex analog domain self-interference elimination apparatus provided by the present invention is described below, and the full-duplex analog domain self-interference elimination apparatus described below and the full-duplex analog domain self-interference elimination method described above may be referred to correspondingly.

Fig. 7 is a schematic structural diagram of a full-duplex analog domain self-interference cancellation apparatus provided in the present invention, and as shown in fig. 7, the full-duplex analog domain self-interference cancellation apparatus according to the embodiment of the present invention includes:

an obtaining module 71, configured to obtain a first transmit signal and a second transmit signal obtained by separating an original transmit signal, where the first transmit signal enters a receiving link after spatial isolation to form a self-interference signal, and the second transmit signal is input to an interference signal reconstructing unit of a full-duplex analog domain self-interference cancellation apparatus;

an adjusting module 72, configured to perform gain and phase adjustment on each reference signal obtained after the second transmit signal is separated based on an optimized input parameter corresponding to each vector modulator in the interference signal reconstruction unit, to obtain a cancellation signal for canceling the self-interference signal; the optimized input parameters of each vector modulator are obtained by sequentially carrying out variable step length optimization training on the I-path input parameters and the Q-path input parameters of each vector modulator according to the optimal parameter direction;

a cancellation module 73, configured to combine the cancellation signal and the self-interference signal to cancel the self-interference signal.

The full-duplex analog domain self-interference elimination device further comprises:

collecting initial output power of the residual self-interference signal;

if the local optimal parameters are the local optimal parameters and the search step length is larger than the minimum step length, the search step length is reduced based on the minimum step length, so that the step of forming a plurality of mutually different auxiliary input parameters based on the search step length and the input parameters is returned to be executed based on a new search step length until the search step length is not larger than the minimum step length, and the optimized input parameters corresponding to the vector modulator to be optimized are obtained.

the plurality of mutually different auxiliary input parameters comprise a first auxiliary input parameter, a second auxiliary input parameter, a third auxiliary input parameter and a fourth step auxiliary parameter; the input parameters comprise I-path input parameters and Q-path input parameters;

the auxiliary residual self-interference signal comprises a first residual self-interference signal, a second residual self-interference signal, a third residual self-interference signal and a fourth residual self-interference signal; the auxiliary output power includes a first auxiliary output power, a second auxiliary output power, a third auxiliary output power, and a fourth auxiliary output power.

if the initial output power is less than or equal to the first auxiliary output power and the initial output power is less than or equal to the second auxiliary output power, keeping the I-path input parameter unchanged.

When the initial output power is greater than the first auxiliary output power or the initial output power is greater than the second auxiliary output power, if the first auxiliary output power is less than or equal to the second auxiliary output power, adding the I path input parameters and the search step length to obtain new I path input parameters; if the first auxiliary output power is larger than the second auxiliary output power, subtracting the I path input parameter from the search step length to obtain a new I path input parameter;

under the condition that the initial output power is greater than the third auxiliary output power or the initial output power is greater than the fourth auxiliary output power, if the third auxiliary output power is less than or equal to the fourth auxiliary output power, adding the Q-path input parameters and the search step length to obtain new Q-path input parameters; and if the third auxiliary output power is greater than the fourth auxiliary output power, subtracting the Q-path input parameter from the search step length to obtain a new Q-path input parameter.

The adjustment module 72 is further configured to:

the optimized input parameters comprise I-path optimized input parameters and Q-path optimized input parameters.

The adjustment module 72 is further configured to:

separating the second transmitting signal in the interference signal reconstruction unit to obtain a plurality of reference signals, wherein each reference signal is respectively input into a vector modulator;

It should be noted that, the apparatus provided in the embodiment of the present invention can implement all the method steps implemented by the method embodiment and achieve the same technical effect, and detailed descriptions of the same parts and beneficial effects as the method embodiment in this embodiment are omitted here.

The above-described embodiments of the apparatus are merely illustrative, and 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 position, or may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment. One of ordinary skill in the art can understand and implement it without inventive effort.

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

1. A method for eliminating self-interference in a full-duplex analog domain is characterized by comprising the following steps:

acquiring a first transmitting signal and a second transmitting signal after the original transmitting signal is separated, wherein the first transmitting signal enters a receiving link after being isolated in a spatial domain to form a self-interference signal, and the second transmitting signal is input to an interference signal reconstruction unit of a full-duplex analog domain self-interference elimination device;

based on the optimized input parameters corresponding to the vector modulators in the interference signal reconstruction unit, respectively performing gain and phase adjustment on each reference signal after the second transmission signal is separated, so as to obtain a cancellation signal for eliminating the self-interference signal;

and combining the cancellation signal and the self-interference signal to cancel the self-interference signal.

2. The method according to claim 1, wherein before the performing gain and phase adjustment on each reference signal separated from the second transmission signal based on the optimized input parameters corresponding to each vector modulator in the interference signal reconstruction unit to obtain the cancellation signal for canceling the self-interference signal, the method further comprises:

collecting initial output power of the residual self-interference signal;

3. The method for self-interference cancellation in full-duplex analog domain according to claim 2, wherein the step-size-variable iterative optimization of the input parameters based on the initial output power and each of the auxiliary output powers to obtain optimized input parameters corresponding to the vector modulator to be optimized includes:

4. The full-duplex analog domain self-interference cancellation method according to claim 3, wherein the plurality of mutually different auxiliary input parameters includes a first auxiliary input parameter, a second auxiliary input parameter, a third auxiliary input parameter, and a fourth step auxiliary parameter; the input parameters comprise I-path input parameters and Q-path input parameters;

performing I-path subtraction on the I-path input parameters and the search step length, and forming second auxiliary input parameters based on a result obtained by the I-path subtraction and the Q-path input parameters;

5. The full-duplex analog domain self-interference cancellation method according to claim 4, wherein the auxiliary residual self-interference signal comprises a first residual self-interference signal, a second residual self-interference signal, a third residual self-interference signal, and a fourth residual self-interference signal; the auxiliary output power comprises a first auxiliary output power, a second auxiliary output power, a third auxiliary output power, and a fourth auxiliary output power;

6. The method for full-duplex analog-domain self-interference cancellation according to claim 5, wherein the adjusting the input parameters of the vector modulator based on the initial output power and each of the auxiliary output powers to obtain new input parameters comprises:

under the condition that the initial output power is greater than the third auxiliary output power or the initial output power is greater than the fourth auxiliary output power, if the third auxiliary output power is less than or equal to the fourth auxiliary output power, adding the Q-path input parameters and the search step length to obtain new Q-path input parameters; and if the third auxiliary output power is greater than the fourth auxiliary output power, subtracting the search step length from the Q-path input parameter to obtain a new Q-path input parameter.

7. The full-duplex analog domain self-interference cancellation method according to claim 2, wherein the optimized input parameters include an I-way optimized input parameter and a Q-way optimized input parameter;

8. A full-duplex analog domain self-interference elimination apparatus, comprising:

the acquisition module is used for acquiring a first transmission signal and a second transmission signal after the separation of an original transmission signal, wherein the first transmission signal enters a receiving link after being isolated in a spatial domain to form a self-interference signal, and the second transmission signal is input to an interference signal reconstruction unit of the analog domain self-interference elimination device;

an adjusting module, configured to perform gain and phase adjustment on each reference signal obtained after the second transmit signal is separated based on an optimized input parameter corresponding to each vector modulator in the interference signal reconstruction unit, to obtain a cancellation signal for canceling the self-interference signal; the optimized input parameters of each vector modulator are obtained by sequentially carrying out variable step length optimization training on the I path input parameters and the Q path input parameters of each vector modulator according to the optimal parameter direction;