KR102327696B1 - Precoding apparatus, and interference processing method thereof - Google Patents

Abstract

The present invention is to calculate the precoding information for each remote module according to the interference processing method that reflects the reliability of the estimated channel of each terminal in a communication environment in which remote modules (RAU, Remote Access Unit) and the terminal are located in the same space. disclosed technology for

Description

Precoding device and interference handling method of precoding device

The present invention relates to a multiuser multiple-input multiple-output (MU-MIMO)-based in-building solution. In a communication environment where remote modules (RAU) and a terminal are located in the same space, the It relates to a technology for calculating precoding information for each remote module according to an interference processing method that reflects the reliability of the remote module.

Evolving from 4G LTE/LTE-Advanced system to 5G NR system, based on MU-MIMO (Multiuser Multiple-Input Multiple-Output) technology, cell capacity increase effect becomes easier It is possible to provide a 5G NR service by recycling space-time frequency resources for each “placed location”.

In MU-MIMO technology, in relation to simultaneous service to multiple terminals, the transmitting end consists of one base station module (DU, Digital Unit) and a plurality of remote modules (RAU, Remote Access Unit), and A system in which terminals exist in the same indoor space may be considered.

In this case, the transmitting end may estimate a channel between the transmitting end and the UE through a Sounding Reference Signal (SRS) signal transmitted by the terminals.

In this regard, it may be assumed that the remote modules are located in a distributed or centralized place in the indoor space, and the terminals are randomly located in the same indoor space.

In this case, while some terminals are located relatively close to the transmitting end, some terminals may be located far from the transmitting end, so that channels of terminals located close to the transmitting end can be estimated relatively accurately, while channels of distant terminals are inaccurate. will estimate

Additionally, assuming that the remote modules are located in a distributed manner, it can be expected that the distance between any terminal and each remote module is different.

In this case, even if the terminal is located close to one remote module, it may be located far from some other remote modules, so that remote modules far from the terminal cannot accurately estimate the channel of the corresponding terminal.

In this way, when the transmitting end performs a service using the conventional MU-MIMO precoding technique based on estimated channel information different from the actual channel, the following problem may occur.

Here, as a conventional MU-MIMO precoding technique, a method of removing interference by utilizing orthogonal properties between a channel matrix and a precoding matrix between terminals and a transmitting end may be considered.

Such a precoding technique can completely remove interference when the transmitting end accurately knows the channel information of the terminals, but as in the above situation, some RAUs cannot effectively remove the interference when they have inaccurate channel information. .

This is because the estimated channel of the terminal to be used when the transmitting end performs the precoding calculation operation is different from the channel of the actual terminals, and even if precoding orthogonal to the estimated channel is calculated, the interference is effectively reduced because it is not orthogonal to the actual channel. This means that it cannot be removed, which will eventually lead to performance degradation.

Accordingly, the present invention intends to propose a new MU-MIMO precoding technique that can overcome the problems of the conventional precoding technique.

The present invention was created in view of the above circumstances, and an object of the present invention is to achieve reliability of the estimated channel of each terminal in a communication environment in which remote modules (RAU) and the terminal are located in the same space. The precoding information for each remote module is calculated according to the interference processing method reflecting the

A precoding apparatus according to an embodiment of the present invention for achieving the above object is integrated for each terminal from estimated channel information estimated for each terminal by two or more remote modules based on SRS (Sounding Reference Signal) signal quality a generator generating estimated channel information; a determining unit for determining the reliability of the estimated channel of each terminal from the integrated estimated channel information; and a calculation unit for calculating integrated precoding information for each terminal according to a different interference processing method based on the reliability of the estimated channel determined for each terminal, slicing it into precoding information corresponding to each of the two or more remote modules, and transmitting it characterized in that

Specifically, the precoding apparatus classifies the terminal into at least one group of a channel reliable group having a reliability equal to or greater than a threshold, and a channel unreliable group having a reliability less than a threshold according to the reliability of the estimated channel determined for each terminal, The interference processing method may be defined according to the group classification result.

Specifically, the determining unit may determine the reliability of the estimated channel of each terminal according to whether a signal-to-noise ratio (SNR) of an SRS signal received from each terminal exceeds a threshold value.

Specifically, the calculator may include, when calculating the precoding vector for the UE of interest, when the reliability of the estimated channel for the interfering UE that the UE of interest may interfere with is less than or equal to a threshold, the average interference power to the interfering UE is less than or equal to a certain value It is possible to calculate a precoding vector that suppresses so that .

Specifically, when the reliability of the estimated channel for both the terminal of interest and the interfering terminal to which the terminal of interest may cause interference is equal to or greater than a threshold, the calculator calculates a precoding vector so that orthogonality of the estimated channel between the terminal of interest and the interfering terminal is established. can be calculated.

Specifically, when the reliability of the estimated channel for the UE of interest is less than or equal to a threshold, the calculator may calculate a precoding vector that suppresses the inter-layer interference power of the UE of interest to be less than or equal to a predetermined value.

Specifically, when the reliability of the estimated channel for the terminal of interest is equal to or greater than a threshold, the calculator may calculate a precoding vector such that orthogonality between channels of layers in the terminal of interest is established.

Specifically, the calculator may calculate a precoding vector such that a ratio of noise generated by a channel estimation error to signal power for a target layer of each terminal is maximized.

The interference processing method of the precoding apparatus according to an embodiment of the present invention for achieving the above object is based on SRS (Sounding Reference Signal) signal quality, each from estimated channel information estimated by two or more remote modules for each terminal. A generating step of generating integrated estimated channel information for the terminal; a determination step of determining the reliability of the estimated channel of each terminal from the integrated estimated channel information; and calculating the integrated precoding information for each terminal according to a different interference processing method based on the reliability of the estimated channel determined for each terminal, slicing and transmitting the precoding information corresponding to each of the two or more remote modules. characterized by including.

Specifically, before the calculating step, according to the reliability of the estimated channel determined for each terminal, the method includes at least one group of a channel reliable group having a reliability equal to or greater than a threshold, and a channel unreliable group having a reliability lower than the threshold. The method may further include a classification step of classifying , so that an interference processing method is defined according to the group classification result.

Specifically, in the determining step, the reliability of the estimated channel of each terminal may be determined according to whether a signal-to-noise ratio (SNR) of the SRS signal received from each terminal exceeds a threshold value. .

Specifically, the calculator may include, when calculating the precoding vector for the UE of interest, when the reliability of the estimated channel for the interfering UE that the UE of interest may interfere with is less than or equal to a threshold, the average interference power to the interfering UE is less than or equal to a certain value It is possible to calculate a precoding vector that suppresses so that .

Specifically, in the calculating step, when the reliability of the estimated channel for both the terminal of interest and the interfering terminal to which the terminal of interest may interfere is equal to or greater than a threshold, the precoding vector is established such that orthogonality of the estimated channel between the terminal of interest and the interfering terminal is established. can be calculated.

Specifically, in the calculating step, when the reliability of the estimated channel for the UE of interest is less than or equal to a threshold, a precoding vector for suppressing the inter-layer interference power of the UE of interest to be less than or equal to a predetermined value may be calculated.

Specifically, in the calculating step, when the reliability of the estimated channel for the UE of interest is equal to or greater than a threshold, the precoding vector may be calculated so that orthogonality between channels of layers in the UE of interest is established.

Specifically, in the calculating step, the precoding vector may be calculated such that a ratio of noise generated by a channel estimation error to signal power for a target layer of each terminal is maximized.

Accordingly, according to the precoding apparatus and the interference processing method of the precoding apparatus of the present invention, the interference reflecting the reliability of the estimated channel of each terminal in a communication environment in which remote modules (RAU) and the terminal are located in the same space By calculating the precoding information for each remote module according to the processing method, it is possible to derive the effect of enabling an efficient response to interference generated in an MU-MIMO (Multiuser Multiple-Input Multiple-Output) based in-building service environment. .

1 is an exemplary diagram for explaining a communication environment according to an embodiment of the present invention.
2 and 3 are exemplary views for explaining a precoding technique according to the prior art.
4 is a block diagram for explaining the configuration of a precoding apparatus according to an embodiment of the present invention.
5 and 6 are exemplary views for explaining a precoding technique according to an embodiment of the present invention.
7 to 9 are operational flowcharts for explaining an interference processing method of a precoding apparatus according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

The present invention relates to a multiuser multiple-input multiple-output (MU-MIMO) based in-building solution technology.

In this regard, FIG. 1 exemplarily shows a communication environment according to an embodiment of the present invention.

1, in a communication environment according to an embodiment of the present invention, a system in which one base station module (DU), N _R remote modules (RAU), and N _U terminals are located in the same indoor space. consider

_{Although it describes a system in which NR} remote modules (RAUs) are located distributedly, it is not necessarily applicable only to the system. For example, _{a system in which NR} RAUs are located in the same space can be considered.

Here, to refer to each remote module (RAU) and each terminal, the remote module (RAU) index r∈{1, ... ,N _R }, and the terminal index u∈{1,... ,N _U } is introduced, and it is assumed that all radios (RAUs) have the same number of N antennas and all terminals have the same number of M antennas.

In addition, it is assumed that the number of layers per terminal is also the same as L.

It should be borne in mind that the technique proposed in an embodiment of the present invention can be applied to a system in which a remote module (RAU) or terminals have different numbers of antennas, and similarly, each terminal has a different number of layers. Of course, it can be applied in any situation.

Meanwhile, it is assumed that the total number of layers is less than or equal to the total number of transmit antennas, so that the inequality N _R N≥N _U L must be satisfied. This assumption is an assumption that must be kept even when using conventional techniques related to linear-based precoding, and since the precoding technique proposed in an embodiment of the present invention is also a linear-based precoding calculation technique, it is necessary to keep the assumption. have.

Hereinafter, a problem that occurs when a conventional precoding technique is applied in a communication environment according to an embodiment of the present invention will be described.

In this regard, FIG. 2 exemplarily shows an operation flow when a conventional precoding technique is applied in a communication environment according to an embodiment of the present invention.

First, each terminal u transmits an SRS (Sounding Reference Signal) signal, and each remote module (RAU) estimates a channel between the remote module (RAU) r and the terminal u based on the received SRS signal.

는 리모트모듈(RAU) r 와 단말 u 간 추정 채널을 낼 수 있다.here,

can provide an estimated channel between the remote module (RAU) r and the terminal u.

Each remote module (RAU) estimates the channel for all terminals and then transmits the estimated channel information to the DU end, and information on the link quality between the terminal and the remote module (RAU) (eg SRS reception SNR) is also provided to the base station module. to (DU).

을 산출한다.In this case, the base station module (DU) integrates the estimated channel matrix for all terminals,

to calculate

Here, the integrated estimation channel means an estimation channel between the terminal u and all remote modules (RAUs).

을 산출한다.In addition, the base station module (DU) is an integrated precoding matrix for each terminal u based on the integrated estimation channel of the terminals,

to calculate

은 단말 u 의 l 번째 레이어에 대한 프리코딩 벡터이다.here,

is a precoding vector for the l-th layer of UE u.

로 슬라이스(slice)한 후 다시 리모트모듈(RAU)에게 전송한다.Then, the base station module (DU) W _u is a precoding matrix corresponding to each remote module (RAU),

After slicing, it is transmitted to the remote module (RAU) again.

이후, 각 리모트모듈(RAU) r은 기지국모듈(DU) 로부터 전달받은 프리코딩 정보를 기반으로 송신 신호 벡터,

을 생성한다.in other words,

Then, each remote module (RAU) r based on the precoding information received from the base station module (DU) transmit signal vector,

create

은 각 단말 u 의 심볼 벡터이며, s_u(l) 은 단말 u 의 l번째 레이어에 대한 심볼이다.here,

is a symbol vector of each terminal u, and s _u (l) is a symbol for the l-th layer of terminal u.

을 수신한다.After that, each remote module (RAU) transmits a transmission signal, and each terminal u sends a signal from the remote module (RAU),

receive

은 잡음 벡터이다.here,

is the noise vector.

Note that although terminal u receives a signal from each remote module (RAU), the communication environment in an embodiment of the present invention is _{a system in which NR} remote modules (RAU) cooperate to transmit signals, so the remote module ( It is very convenient to express signals transmitted by RAUs by concatenating them into one matrix or vector.

과

를 각각 단말 u의 실제 통합 채널과 리모트모듈(RAU)들이 협력하여 송신하는 송신 벡터라 하면,

는 아래 [수식 1]과 같이 정의될 수 있다.in other words,

class

If is a transmission vector transmitted by the actual integrated channel of terminal u and the remote modules (RAUs) cooperatively,

can be defined as in [Equation 1] below.

[Formula 1]

Thereafter, each terminal u detects its own signal through the signal of the following [Equation 2] obtained after performing an equalization operation on the received signal.

[Formula 2]

는 각 단말 u의 등화(equalization) 행렬이며,

는 단말 u의 등화 행렬이 곱해진 통합 채널 행렬이며,

는 단말 u의 l번째 레이어에 대한 채널 벡터이다.here,

is the equalization matrix of each terminal u,

is the unified channel matrix multiplied by the equalization matrix of terminal u,

is a channel vector for the l-th layer of UE u.

Meanwhile, representative conventional techniques that can be used when the base station module (DU) calculates the integrated precoding matrix for each terminal u in step ⑥ of FIG. 2 include, for example, Channel Inversion (CI), Regularized CI (RCI), and Block Diagonalization (BD) technique exists.

These conventional techniques have one thing in common, which is that they use orthogonality between the integrated estimation channel and W _{u to remove interference when calculating the UE u's integrated precoding matrix, W u .}

In this regard, FIG. 3 exemplarily shows a flowchart of calculating _{W u} for each terminal u according to the BD technique among conventional techniques.

Steps ③ and ⑤ in FIG. 3 are steps using orthogonality to remove interference (Multiuser Interference, MUI) and inter-layer interference to other terminals, respectively.

에 대해 SVD를 수행하면 좌측 유니터리 행렬(left unitary matrix), 대각 행렬, 우측 유니터리 행렬(right unitary matrix)을 도출할 수 있다.in step ③

If SVD is performed on , a left unitary matrix, a diagonal matrix, and a right unitary matrix can be derived.

와 직교하는 열 벡터들이다. _{Then, the N R} Nth _{column vector from the (N U - 1} )L+1th column vector of the right unitary matrix is

are column vectors orthogonal to .

이 된다.Therefore, a matrix can be created by combining L column vectors among the column vectors, and this matrix is

becomes this

는 단말 u를 제외한 나머지 모든 단말들의 추정 채널과 직교 관계를 갖고 있기 때문에

를 적용하면 타 단말들에게 미치는 MUI를 제거할 수 있다는 점이다(

).Here, it should be noted

Since has an orthogonal relationship with the estimated channels of all terminals except for terminal u

The point is that MUI affecting other terminals can be removed by applying

).

는

를 적용했을 경우 단말 u의 채널을 나타낸 것이다.On the other hand, in step ④

Is

In the case of applying , it represents the channel of terminal u.

를 대각화하며, 그리고, 이를 위해 행렬을 대각화 하는데 사용되는 대표적인 방법인 SVD 기법을 다시 적용한다.Now in step ⑤ to remove the inter-layer interference

, and, for this, the SVD technique, which is a representative method used to diagonalize a matrix, is applied again.

에 대해 SVD를 적용한 후 얻어진 우측 유니터리 행렬,

을

로 설정하고 최종 프리코딩 행렬

을 산출한다.in other words,

Right unitary matrix obtained after applying SVD to

second

set to and the final precoding matrix

to calculate

At this time, each column vector of the right unitary matrix satisfies mutual orthogonality.

That is, using the right unitary matrix means that the column vector in the matrix is applied as a precoding vector corresponding to each layer and inter-layer interference is removed using orthogonality.

The advantage of such a conventional precoding technique is that interference can be almost completely removed when the accuracy of the estimation channel is high.

However, it is difficult to accurately estimate channel information in an actual system.

That is, when the remote modules (RAUs) are distributed, some remote modules (RAUs) are located relatively close to any terminal, while the remaining remote modules (RAU) will be relatively far away.

In this case, the channel will be estimated inaccurately due to poor link quality between remote modules (RAUs) and the terminal, and each remote module (RAU) transmits the estimated channel information to the base station module (DU) and receives it. It is necessary to consider that the base station module (DU) generates an integrated estimation channel generated by integrating the received channel information.

At this time, the combined estimated channel and the combined actual channel will be quite different due to the channels estimated by the remote modules (RAUs) having poor link quality.

That is, even if precoding having orthogonality with the estimated channel is applied, the orthogonality with the actual channel will not be satisfied.

Accordingly, in an embodiment of the present invention, in order to solve the problems of the prior art, a new precoding technique that reflects the reliability of the estimated channel of each terminal is proposed.

Hereinafter, a precoding apparatus according to an embodiment of the present invention will be described in detail with reference to FIG. 4 .

Prior to the description, the description will be continued on the assumption that the precoding apparatus according to an embodiment of the present invention is a configuration implemented in the base station module (DU) in the communication environment described with reference to FIG. 1 above.

As shown in FIG. 4 , the precoding apparatus 100 according to an embodiment of the present invention determines the reliability of the estimated channel of the generating unit 10 for generating the integrated estimated channel information for each terminal, and each terminal. It includes a determining unit 20, a classification unit 30 for classifying a terminal group according to the reliability determination result, and a calculation unit 40 for calculating precoding information.

In addition, the precoding apparatus 100 according to an embodiment of the present invention configures the communication unit 50 responsible for the actual communication function with each remote module (RAU) according to the implementation in the base station module (DU) in the communication environment. may include more.

Here, the communication unit 50 includes, for example, an antenna system, an RF transceiver, one or more amplifiers, a tuner, one or more oscillators, a digital signal processor, a codec (CODEC) chipset, and a memory, but is not limited thereto, and this function is All known circuits to perform may be included.

All or at least part of the configuration of the precoding apparatus 100 may be implemented in the form of a hardware module or a software module, or may be implemented in a form in which a hardware module and a software module are combined.

Here, the software module may be understood as, for example, an instruction executed by a processor that controls an operation in the precoding device 100 , and such an instruction may have a form mounted in a memory in the precoding device 100 . will be.

As a result, the precoding apparatus 100 according to an embodiment of the present invention can calculate the precoding information for each remote module according to the interference processing method reflecting the reliability of the estimated channel of each terminal through the above-described configuration. Hereinafter, the configuration in the precoding apparatus 100 for realizing this will be described in more detail.

The generating unit 10 performs a function of generating integrated estimated channel information.

)를 생성하게 된다.More specifically, the generating unit 10 includes estimated channel information estimated for each terminal based on the SRS (Sounding Reference Signal) signal quality received by each remote module (RAU) from the terminal, and the terminal and the remote module (RAU). Information on inter-link quality (eg, SRS reception SNR) is received from each remote module (RAU), and based on this, integrated estimated channel information (integrated estimated channel matrix,

) will be created.

Meanwhile, here, the operation until the generation unit 10 receives the estimated channel information and information on the link quality between the terminal and the remote module (RAU) (eg, SRS reception SNR) is according to an embodiment of the present invention. 5, which shows a schematic procedure of the precoding technique as an example, corresponds to steps ① to ④, and the operation of generating the integrated estimation channel information corresponds to step ⑤.

The determination unit 20 determines the reliability of the estimated channel of each terminal.

More specifically, when the generation of the integrated estimated channel information for each terminal is completed, the determining unit 20 determines the reliability of the estimated channel of each terminal from the integrated estimated channel information.

In this case, the determining unit 20 may determine the reliability of the estimated channel of each terminal according to whether a signal-to-noise ratio (SNR) of the SRS signal received from each terminal exceeds a threshold value. .

To this end, in an embodiment of the present invention, the error variance value for the estimated channel of the terminals is calculated. Here, the error variance value calculation method may follow, for example, the following method.

과 실제 채널,

간 차이를 채널 추정 오류,

라고 하면, 추정 채널 오류

에 대한 분산 값은 SRS 신호의 신호 대비 잡음 비율 (SNR, Signal to Noise Ratio) 크기에 반비례한다.That is, the estimated channel,

and real channels,

the difference between the channel estimation error,

, the estimated channel error

The variance value for ? is inversely proportional to the signal-to-noise ratio (SNR) magnitude of the SRS signal.

In other words, the larger the received SNR, the more accurately the channel can be estimated. For example, when estimating the channel using the MMSE technique, the relationship between the SRS received SNR size and the error variance value of the estimated channel can be expressed as [Equation 3] below. have.

[Equation 3]

Here, P _SRS denotes SRS transmission power, σ ² denotes noise power, and γ denotes SRS reception SNR.

After calculating the estimated channel error variance, it can be determined whether the corresponding channel information is reliable.

For example, after setting a threshold value for the estimated channel variance value, element values in the estimated channel matrix are compared with the threshold value. If a significant number of element values are greater than or equal to the threshold value, it is determined that the estimated channel information of the terminal is unreliable. can do.

That is, when the above [Equation 3] is used, the threshold value of the SRS received SNR γ is set and the SNR of the received SRS signal is compared with the threshold. It can be determined that there is no

The classification unit 30 performs a function of classifying the terminal group according to the reliability determination result.

More specifically, when the reliability determination for the estimated channel of each terminal is completed, the classification unit 30 classifies each terminal into a terminal group according to the reliability determination result.

In this case, the classification unit 30 may classify the channel reliability group (Ω) having a reliability equal to or greater than a threshold value and a channel unreliability group having a reliability lower than the threshold value (Ψ) according to the reliability of the estimated channel determined for each terminal.

This group classification operation corresponds to step ⑥ of FIG. 5 exemplified above.

The calculator 40 performs a function of calculating the integrated precoding information for each terminal.

More specifically, the calculator 40 calculates the integrated precoding information (integrated precoding matrix, Wu) for each terminal according to different interference processing methods based on the reliability of the estimated channel determined for each terminal.

In other words, the calculator 40 calculates the integrated precoding information (integrated precoding matrix, Wu) for each terminal according to a different interference processing method defined according to the group classification result according to the estimated channel reliability of each terminal. , which corresponds to step ⑦ of FIG. 5 exemplified above.

First, an operation of calculating integrated precoding information for a terminal belonging to a channel reliability group (Ω) will be described as follows.

When the terminal u belongs to the channel reliable group (Ω), it is checked whether there are terminals belonging to the channel unreliable group (Ψ) among the remaining terminals.

If all other terminals also belong to the channel reliability group (Ω), the precoding technique according to an embodiment of the present invention operates in the same way as the conventional technique.

This is because the estimated channels of all terminals are reliably accurate.

However, when at least one terminal among the remaining terminals belongs to the channel unreliable group (Ψ), the conventional technique is applied differently.

First, in order to process the interference on the remaining terminals except for terminal u among terminals belonging to the channel reliability group (Ω), the precoding vector for removing interference by utilizing the orthogonality between the estimated channels of the terminals as in the conventional technique is added. Derive a conditional expression for

On the other hand, a conditional expression for a precoding vector capable of suppressing the average interference intensity to a predetermined value or less is derived for the terminals belonging to the channel unreliable group (Ψ).

에게 미치는 간섭도 처리 해야 한다.On the other hand, in the _{calculation of the precoding vector, w u} (l), the remaining layers other than the l-th layer among the signals of the terminal u as well as the interference to other terminals,

Interference to the person must also be addressed.

Since the estimated channel of UE u is similar to the actual channel (eg, u∈Ω), the inter-layer interference of UE u is handled in the same way as in the prior art.

That is, a conditional expression for a precoding vector capable of removing interference is derived by utilizing the inter-channel orthogonality of the layer.

Finally, the precoding vector, w _u (l), performs an operation to process the signal for the l-th layer of the terminal u.

Note that in this operation, since the estimated channel of terminal u does not perfectly match the real channel even if the reliability is high, a difference exists between the estimated channel and the real channel, and the difference causes noise.

Therefore, an equation capable of maximizing the ratio of noise power that may occur due to the estimated channel and the actual channel to the signal power for the l-th layer of the terminal u is derived. Then, a precoding vector that can satisfy the above conditions, w _u (l), is calculated.

Next, the operation of calculating the integrated precoding information for the terminal belonging to the channel unreliable group (Ψ) is as follows.

When the terminal u belongs to the channel unreliable group (Ψ), since the terminal belonging to the channel unreliable group (Ψ) exists, the precoding technique according to an embodiment of the present invention must always operate differently from the conventional technique.

Even when terminal u belongs to the channel unreliable group (Ψ) (u∈Ψ), the operation to be performed to handle the interference that terminal u has on other terminals is performed when terminal u belongs to the channel unreliable group (Ω). Same as (u∈Ω).

That is, a conditional expression for a precoding vector that allows the interference signal of UE u to be removed for UEs that can trust the estimated channel among other UEs is derived, while the interference signal that affects UEs whose estimated channel is unreliable is that of the interference signal. A conditional expression for the precoding vector is derived so that the power is less than or equal to a certain value.

The reason that the same operation is performed regardless of the group to which the terminal u belongs when processing the interference to other terminals is that the estimated channel information of the remaining terminals is considered, not the estimated channel information of the terminal u.

에게 미치는 간섭을 처리하는 동작은 단말 u가 채널신뢰가능그룹(Ω)에 속한 경우(u∈Ω)와 다르다.On the other hand, when terminal u belongs to the channel unreliable group (Ψ) (u∈Ψ), the remaining layers other than the lth layer among the signals of terminal u,

The operation of handling the interference to the terminal u is different from the case (u∈Ω) when the terminal u belongs to the channel reliability group (Ω).

번째 레이어에 미칠 간섭 전력이 일정 값 이하가 되도록 하는 프리코딩 벡터에 대한 조건식을 도출한다.That is, rather than using the orthogonal property because the estimated channel reliability of terminal u is low

A conditional expression for the precoding vector is derived so that the interference power to the th layer is less than or equal to a predetermined value.

Thereafter, the operation of maximizing the signal-to-noise ratio of the l-th layer of the terminal u is performed in the same manner as when the terminal u belongs to the channel reliability group (Ω) (u∈Ω).

As described above, in the precoding technique according to an embodiment of the present invention, interference is processed by utilizing orthogonality for terminals belonging to the channel reliable group (Ω) as in the conventional technique, but to the terminals belonging to the channel unreliable group (Ψ). This can be summarized as processing the interference so that it becomes less than a certain size without utilizing orthogonality.

Hereinafter, in order to more clearly explain the precoding technique according to an embodiment of the present invention, a scenario is assumed for a case where a terminal belonging to a channel unreliable group (Ψ) exists (Ψ≠), How the coding vector is calculated will be described.

In this regard, in FIG. 6, when N _RAU = 4; N _UE = 4; N = 4, M = L = 4, a scenario in which terminals are grouped based on SRS signal quality received from terminals for each remote module (RAU) and how to calculate a precoding vector for terminals belonging to each group as an example.

In FIG. 6( a ), blue indicates very good quality, green indicates good quality, purple indicates normal quality, and red indicates bad quality for SRS received SNR quality, and then each estimated channel information is determined according to an embodiment of the present invention. It is converted into integrated estimation channel information as shown in FIG. 6(b).

Thereafter, according to the result of performing terminal grouping based on the integrated estimated channel information of each terminal, in FIG. 6(b), terminal 1, terminal 2, and terminal 3 are SNR quality of the SRS signal received from each remote module (RAU). While this is generally higher than the threshold value and belongs to the channel reliability group (Ω), the terminal 4 whose SRS signal quality is below the threshold value belongs to the channel unreliability group (Ψ).

에게 미치는 간섭 처리 조건식 도출, ③ 관심 단말 u의 타겟 레이어 l의 신호 처리 조건식 도출, ④ 도출된 조건 식 반영하여 프리코딩 벡터 산출하는 동작 들을 순차적으로 수행한다.In an embodiment of the present invention, based on the channel reliability of these terminals, ① derivation of an interference processing conditional expression that the terminal of interest u has on the remaining terminal(s) u', ② a layer other than the target layer l among the signals of the terminal of interest u

The following operations are sequentially performed: derivation of an interference processing conditional expression on the target u, ③ deriving a signal processing conditional expression of the target layer l of the terminal u of interest, and ④ reflecting the derived conditional expression to calculate the precoding vector.

To explain this, in FIG. 6(c), the operation of calculating the _{precoding vector w 1} (1) for the first layer of UE 1 among UE 1, UE 2, and UE 3 belonging to the channel reliability group (Ω) is taken as an example. , and in FIG. 6(d), the operation of calculating the _{precoding vector w 4} (1) for the first layer for UE 4 belonging to the channel unreliable group Ψ is taken as an example.

First, the process of deriving the interference processing conditional expression that the terminal of interest u exerts on the remaining terminal(s) u' is described as follows (①).

을 고려한다.For deriving an interference processing conditional expression, a terminal other than terminal u

consider

_{For example, when deriving the precoding vector w 1} (1) for the first layer of UE 1 in FIG. 6 (c), other UEs, UE 2, UE 3, and UE 4 correspond to UE u', _{Similarly, when w 4} (1) is derived in FIG. 6 (d), terminal 1, terminal 2, and terminal 3 correspond to terminal u'.

Here, the interference processing method that can affect the terminal varies according to the group to which the terminal u' belongs.

와 w_{_u}(l) 간에는 직교성이 성립해야 하는데, 이는 아래 [수식 4]와 같이 표현될 수 있다.If u'∈Ω, since the channel reliability of terminal u' is high, in the precoding technique according to an embodiment of the present invention, as in the conventional technique, the estimated channel of terminal u',

Orthogonality must be established between and w _{_u} (l), which can be expressed as [Equation 4] below.

[Equation 4]

조건이 도출된 것을 확인할 수 있는 반면, 도 6 (d)에서 단말 1, 단말 2, 단말 3의 추정 채널은 신뢰할 수 있으므로 w₄(1) 산출 시

조건이 도출된 것을 확인할 수 있다.In FIG. 6 (c), since the estimated channels of terminal 2 and terminal 3 are reliable, _{when calculating w 1} (1)

While it can be confirmed that the condition is derived, in FIG. 6 (d), the estimated channels of terminal 1, terminal 2, and terminal 3 are reliable, so _{when calculating w 4} (1)

It can be confirmed that the condition has been derived.

On the other hand, in the case of u'∈Ψ, an attempt to remove interference using orthogonality is ineffective.

Therefore, in this case, in the precoding technique according to an embodiment of the present invention, w _u (l) is derived so that the interference power to the terminal u' is equal to or less than a predetermined value.

When w _u (l) is applied, the interference signal experienced by the terminal u' will be described as follows.

은 추정 채널,

과 오류 채널

의 합인

으로 구성된다.Here, the actual channel of terminal u',

is the estimated channel,

and error channel

the sum of

is composed of

이며, 따라서, w_u(l)에 의해 단말 u가 단말 u'에게 미칠 간섭 신호는 다음 [수식 5]와 같이 표현될 수 있다.At this time, according to the aforementioned [Equation 2], the relationship between channels before and after the equalization operation is

Therefore, the interference signal that the terminal u will affect the terminal u' by _{w u (l) can be expressed as in Equation 5 below.}

[Equation 5]

과

는 각각 등화 적용 후의 단말 u'의 추정 채널과 오류 채널이다.in the above expression

class

are the estimated channel and error channel of terminal u' after applying equalization, respectively.

The interference processing method to affect the terminal u' belonging to Ψ is to suppress the interference power to the terminal u' to be less than or equal to a predetermined value.

의 모든 원소들의 값을 일정 값 이하로 억제하는 것이다.That is, according to the above [Equation 5],

It is to suppress the values of all elements of , below a certain value.

의 원소들은 사전에 알 수 없는 랜덤 변수이기 때문에 등화 적용 후의 오류 채널

의 원소들 역시 사전에 알 수 없는 랜덤 변수이다.However, the error channel

Since the elements of are random variables that are not known in advance, the error channel after applying equalization

The elements of are also random variables that cannot be known in advance.

를 일정 값 이하로 하는 w_u(l)를 생성하는 것은 불가능하며, 이에 본 발명의 일 실시예에서는 순간적인 간섭 전력 대신 평균 간섭 전력,

을 일정 값 이하가 되도록 억제하는 w_u(l)를 생성한다.Thus, instantaneous power,

_{It is impossible to generate w u} (l) that is equal to or less than a certain value, and therefore, in an embodiment of the present invention, average interference power instead of instantaneous interference power,

_{Generates w u} (l) that suppresses to be below a certain value.

의 원소들은 분포는 평균은 0이고 분산은 SRS 수신 SNR에 의해 결정되는 랜덤 변수들이기 때문에

의 공분산(covariance) 행렬인

는 SRS 수신 정보로 알아낼 수 있고, 따라서

를 일정 값,

이하가 되도록 하는 w_u(l)를 찾는 것은 가능하다.

Since the distributions of the elements of are random variables whose mean is 0 and the variance is determined by the SRS received SNR,

is the covariance matrix of

can be found by the SRS reception information, so

is a constant value,

It is possible to find w _{u (l) such that}

이하로 억제하는 조건식은 다음 [수식 6]과 같이 도출할 수 있다.Through this, the average interference power that will affect the terminal u'

The conditional expression suppressing the following can be derived as follows [Equation 6].

[Equation 6]

이하로 억제하는 조건 식

이 도출된 것을 확인할 수 있다.In FIG. 6 (c), since the estimated channel of UE 4 has low reliability, the average interference power of the interference to UE 4 when _{w 1 (1) is applied is calculated.}

Conditional expression to suppress below

It can be seen that this has been derived.

에게 미치는 간섭 처리 조건식 도출 과정을 설명하면 다음과 같다(②).Next, a layer other than the target layer l among the signals of the UE u of interest

The process of deriving the interference processing conditional expression on the

Before explaining the inter-layer interference processing conditions, a channel vector through which the UE receives the layer is newly introduced.

을 도입하며,

은 단말 u의 신호 중 l번째 레이어가 아닌 다른 레이어인

를 의미한다.For this, a new index into the layer

is introduced,

is a layer other than the l-th layer among the signals of terminal u.

means

은 2, 3, 4 이다.For example, since FIGS. 6 (c) and (d) are examples for w ₁ (1) and w ₄ (1), respectively

is 2, 3, 4.

First, it is possible to examine the derivation of the interference cancellation conditional expression when the terminal u belongs to the channel reliability group (Ω).

When the terminal u belongs to the channel reliability group (Ω), interference is removed by utilizing the orthogonal property as in the conventional technique.

번째 레이어에 대한 등화 추정 채널 벡터,

와 직교하는 프리코딩 조건식을 아래 [수식 7]과 같이 도출한다.That is, the terminal u

equalized estimation channel vector for the th layer,

A precoding conditional expression orthogonal to and is derived as shown in [Equation 7] below.

[Equation 7]

조건이 도출된 것을 확인할 수 있다.For example, in order to remove the inter-layer interference of UE 1 in FIG. 6 ( c )

It can be confirmed that the condition has been derived.

In addition, it is possible to examine the derivation of the interference cancellation conditional expression when the terminal u belongs to the channel unreliable group (Ψ).

When the terminal u belongs to the channel unreliable group (Ψ), the average interference power is suppressed below a certain value, and this conditional expression is similar to [Equation 6] and is given as the following [Equation 8].

[Equation 8]

이 도출된 것을 확인할 수 있다.In FIG. 6 (d), since UE 4 belongs to the channel unreliable group (Ψ), a derived equation for suppressing inter-layer interference

It can be seen that this has been derived.

Next, the process of deriving the signal processing conditional expression of the target layer l of the UE u of interest is described as follows (③).

The magnetic signal processing operation maximizes the ratio of noise generated by a channel estimation error to signal power of a target layer in a received signal.

이므로 타겟 레이어의 신호 전력은

이고 오류 채널로 인한 (평균) 잡음 전력은

이다.After the equalization operation, the relationship between the actual signal channel, the estimated channel, and the error channel is

Therefore, the signal power of the target layer is

and the (average) noise power due to the error channel is

am.

를 계산하기 위해 필요한

정보는 SRS 수신 SNR 정보를 통해 알아낼 수 있다.here

needed to calculate

The information may be found through SRS reception SNR information.

_{The magnetic signal processing conditional expression calculates w u} (l) capable of maximizing the noise component compared to the actual magnetic signal, and it can be derived as [Equation 9] below the corresponding conditional expression.

[Equation 9]

Here, it should be noted that the magnetic signal processing operation is performed the same regardless of the group to which the terminal belongs.

This is because, since there is always a difference between the estimated channel and the actual channel, it is effective to maximize the signal-to-noise ratio not only for terminals with low estimated channel reliability but also for terminals with high estimated channel reliability.

Next, the process of calculating the precoding vector by reflecting the derived conditional expression is described as follows (④)

_{The optimization equation for calculating the precoding vector, w u} (l) for the l-th layer for the terminal u by reflecting the equation derived above can be defined as [Equation 10] below.

[Equation 10]

와

를 w_u(l)에 대해 각각 이차 형식(quadratic form) 형태로 변형한 것이다.The objective function of [Equation 10] above is

Wow

is transformed into a quadratic form for w _{u (l), respectively.}

과

에 대한 함수 식임을 명확하게 보이기 위해서이다. The reason for expressing in quadratic form is that the objective function is w _u (l) and two matrices of _{size N R} NХN _{R N}

class

This is to clearly show that it is a function expression for .

In the precoding technique according to an embodiment of the present invention, a solution obtained by solving the above optimization problem [Equation 10] _{is set to w u} (l). That is, w _u (l) is all of the MUI processing conditions shown in [Equation 4] and [Equation 6] and inter-layer interference processing conditions that vary depending on the group to which the UE belongs as shown in Equations [Equation 7] and [Equation 8]. It can be understood that a vector satisfying the magnetic signal processing condition shown in [Equation 9] was found through the above optimization problem [Equation 10].

On the other hand, the optimization problem related to [Equation 10] can be found through the interior-point algorithm. However, the complexity required to find the solution of problem (10) is very complicated with NP-hard.

Accordingly, various types of complexity reduction schemes can be utilized, and the following exemplary scheme can be presented in an embodiment of the present invention.

First, the reason why the optimization problem [Equation 10] cannot be a convex problem is that the objective function of [Equation 10] is not a convex function.

와 타겟 레이어의 신호 전력을 나타내는 함수,

를 각각 따로 고려할 경우 두 함수 모두 w_u(l)에 대한 convex 함수라는 점이다.However, it should be noted that among the objective functions of [Equation 10], the function representing the noise level,

and a function representing the signal power of the target layer,

Considering each separately, both functions are _{convex functions for w u} (l).

과

은 PSD(positive-semi definite)행렬이기 때문이다.The reason is that the matrix in each numerator and denominator

class

This is because is a positive-semi definite (PSD) matrix.

This is due to the fact that, when expressed in quadratic form, if the corresponding matrix is a PSD matrix, then the function is a convex function.

의 계수(rank)가 1인 점을 적극 활용하는 것이다.[Equation 10] The main idea of transforming the problem into a convex optimization problem is

It takes advantage of the fact that the rank of is 1.

의 계수 (rank)가 1이면

는 단지 하나의 변수에 의해서 정의되는 1차원 convex 함수로 치환할 수 있다.

If the coefficient (rank) of is 1

can be substituted with a one-dimensional convex function defined by only one variable.

Using this fact, the objective function of [Equation 10] determined by _{N RAU N variables in the present specification can be changed to a convex function determined by N RAU} N-1 variables, which is based on the following principle possible.

First, since the function of the molecule is a one-dimensional convex problem, the optimal variable that can maximize the function of the molecule can be found first with very little complexity.

_{Thereafter, N RAU} N-1 variables that minimize the denominator are optimized while the optimal variable is fixed.

As mentioned above, since the denominator function is also a convex function, the N _RAU N-1 optimal variables can be found with little complexity.

Since the precoding technique according to an embodiment of the present invention finds a one-dimensional optimal variable that maximizes a magnetic signal _{and sequentially finds N RAU} N-1 optimal variables that _{minimize a noise component while the value is fixed, N RAU} N The performance cannot be as good as [Equation 10], which finds the optimal variables at the same time.

In order to achieve the same performance, _{after finding the N RAU} N-1 optimal variables that minimize the noise component, the values are fixed again and an iterative process of finding the optimal variables maximizing the magnetic signal is performed.

The calculator 40 performs a function of transmitting the integrated precoding information.

More specifically, the calculator 40 converts the calculated integrated precoding information into precoding information (precoding matrix) corresponding to each remote module (RAU) for each terminal or when the calculation of the integrated precoding information is completed. Slice and deliver to each remote module (RAU).

This corresponds to step ⑧ of FIG. 5 exemplified above.

Meanwhile, in this regard, each remote module (RAU) generates and transmits a transmission signal for each terminal based on the received precoding information (precoding matrix), and each terminal receiving it equalizes the received signal. ), it detects its own signal through the signal obtained through this operation.

This corresponds to steps ⑨ to ⑬ of FIG. 5 exemplified above, and may be understood as the same operation as steps ⑧ to ⑫ described with reference to FIG. 2 as a prior art.

Above, according to the configuration of the precoding apparatus 100 according to an embodiment of the present invention, the reliability of the estimated channel of each terminal in a communication environment in which remote modules (RAU) and the terminal are located in the same space. By calculating the precoding information for each remote module according to the reflected different interference processing methods, the effect of enabling efficient response to interference occurring in the MU-MIMO (Multiuser Multiple-Input Multiple-Output) based in-building service environment is derived. know you can do it.

Hereinafter, an interference processing method of the precoding apparatus 100 according to an embodiment of the present invention will be described with reference to FIG. 7 .

)를 생성한다(S10-S20).First, the generating unit 10 includes estimated channel information estimated for each terminal based on the SRS (Sounding Reference Signal) signal quality received by each remote module (RAU) from the terminal, and the link between the terminal and the remote module (RAU). Receives quality information (eg, SRS reception SNR) from each remote module (RAU) and based on this, integrated estimated channel information (integrated estimated channel matrix,

) is generated (S10-S20).

Next, when the generation of the integrated estimated channel information for each terminal is completed, the determining unit 20 determines the reliability of the estimated channel of each terminal from the integrated estimated channel information ( S30 ).

In this case, the determining unit 20 may determine the reliability of the estimated channel of each terminal according to whether a signal-to-noise ratio (SNR) of the SRS signal received from each terminal exceeds a threshold value. .

Furthermore, when the reliability determination for the estimated channel of each terminal is completed, the classification unit 30 classifies each terminal into a terminal group according to the reliability determination result ( S40 ).

In this case, the classification unit 30 may classify the channel reliability group (Ω) having a reliability equal to or greater than a threshold value and a channel unreliability group having a reliability lower than the threshold value (Ψ) according to the reliability of the estimated channel determined for each terminal.

Furthermore, the calculator 40 calculates integrated precoding information (integrated precoding matrix, Wu) for each terminal according to different interference processing methods based on the reliability of the estimated channel determined for each terminal ( S50 ).

In other words, the calculator 40 calculates the integrated precoding information (integrated precoding matrix, Wu) for each terminal according to different interference processing methods defined according to the group classification result according to the estimated channel reliability of each terminal. .

First, referring to FIG. 8 , an operation of calculating integrated precoding information for a terminal belonging to a channel reliability group Ω will be described as follows.

When the terminal u belongs to the channel reliable group (Ω), it is checked whether there are terminals belonging to the channel unreliable group (Ψ) among the remaining terminals.

If all other terminals also belong to the channel reliability group (Ω), the precoding technique according to an embodiment of the present invention operates in the same way as the conventional technique.

This is because the estimated channels of all terminals are reliably accurate.

However, when at least one terminal among the remaining terminals belongs to the channel unreliable group (Ψ), the conventional technique is applied differently.

First, in order to process the interference on the remaining terminals except for terminal u among terminals belonging to the channel reliability group (Ω), the precoding vector for removing interference by utilizing the orthogonality between the estimated channels of the terminals as in the conventional technique is added. Derive a conditional expression for

On the other hand, a conditional expression for a precoding vector capable of suppressing the average interference intensity to a predetermined value or less is derived for the terminals belonging to the channel unreliable group (Ψ).

에게 미치는 간섭도 처리 해야 한다.On the other hand, in the _{calculation of the precoding vector, w u} (l), the remaining layers other than the l-th layer among the signals of the terminal u as well as the interference to other terminals,

Interference to the person must also be addressed.

Since the estimated channel of UE u is similar to the actual channel (eg, u∈Ω), the inter-layer interference of UE u is handled in the same way as in the prior art.

That is, a conditional expression for a precoding vector capable of removing interference is derived by utilizing the inter-channel orthogonality of the layer.

Finally, the precoding vector, w _u (l), performs an operation to process the signal for the l-th layer of the terminal u.

Note that in this operation, since the estimated channel of terminal u does not perfectly match the real channel even if the reliability is high, a difference exists between the estimated channel and the real channel, and the difference causes noise.

Therefore, an equation capable of maximizing the ratio of noise power that may occur due to the estimated channel and the actual channel to the signal power for the l-th layer of the terminal u is derived. Then, a precoding vector that can satisfy the above conditions, w _u (l), is calculated.

Next, referring to FIG. 9 , an operation of calculating integrated precoding information for a terminal belonging to the channel unreliable group ? is as follows.

When the terminal u belongs to the channel unreliable group (Ψ), since the terminal belonging to the channel unreliable group (Ψ) exists, the precoding technique according to an embodiment of the present invention must always operate differently from the conventional technique.

Even when terminal u belongs to the channel unreliable group (Ψ) (u∈Ψ), the operation to be performed to handle the interference that terminal u has on other terminals is performed when terminal u belongs to the channel unreliable group (Ω). Same as (u∈Ω).

That is, a conditional expression for a precoding vector that allows the interference signal of UE u to be removed for UEs that can trust the estimated channel among other UEs is derived, while the interference signal that affects UEs whose estimated channel is unreliable is that of the interference signal. A conditional expression for the precoding vector is derived so that the power is less than or equal to a certain value.

The reason that the same operation is performed regardless of the group to which the terminal u belongs when processing the interference to other terminals is that the estimated channel information of the remaining terminals is considered, not the estimated channel information of the terminal u.

에게 미치는 간섭을 처리하는 동작은 단말 u가 채널신뢰가능그룹(Ω)에 속한 경우(u∈Ω)와 다르다.On the other hand, when terminal u belongs to the channel unreliable group (Ψ) (u∈Ψ), the remaining layers other than the lth layer among the signals of terminal u,

The operation of handling the interference to the terminal u is different from the case (u∈Ω) when the terminal u belongs to the channel reliability group (Ω).

번째 레이어에 미칠 간섭 전력이 일정 값 이하가 되도록 하는 프리코딩 벡터에 대한 조건식을 도출하며, 단말 u가 채널신뢰가능그룹(Ω)에 속한 경우(u∈Ω)와 동일하게 단말 u의 l번째 레이어의 신호 대비 잡음 비율을 최대화하는 동작을 수행한다.That is, rather than using the orthogonal property because the estimated channel reliability of terminal u is low

The conditional expression for the precoding vector is derived so that the interference power to the second layer is less than or equal to a certain value, and the lth layer of the terminal u is the same as when the terminal u belongs to the channel reliability group (Ω) (u∈Ω). The operation is performed to maximize the signal-to-noise ratio of

As described above, in the precoding technique according to an embodiment of the present invention, interference is processed by utilizing orthogonality for terminals belonging to the channel reliable group (Ω) as in the conventional technique, but to the terminals belonging to the channel unreliable group (Ψ). This can be summarized as processing the interference so that it becomes less than a certain size without utilizing orthogonality.

Then, referring back to FIG. 7 , the calculator 40 converts the calculated integrated precoding information to the precoding information (precoding information corresponding to each remote module RAU) for each terminal or when the calculation of the integrated precoding information is completed. coding matrix) and transmitted to each remote module (RAU) (S60-S70).

Meanwhile, in this regard, each remote module (RAU) generates and transmits a transmission signal for each terminal based on the received precoding information (precoding matrix), and each terminal receiving it equalizes the received signal. ), it detects its own signal through the signal obtained through this operation.

As described above, according to the interference processing method of the precoding apparatus 100 according to an embodiment of the present invention, in a communication environment in which remote modules (RAU) and the terminal are located in the same space, the estimated channel of each terminal is By calculating precoding information for each remote module according to different interference processing methods reflecting reliability, it is possible to efficiently respond to interference that occurs in an MU-MIMO (Multiuser Multiple-Input Multiple-Output) based in-building service environment. It can be seen that .

The interference processing method according to an embodiment of the present invention may be implemented in the form of program instructions that can be executed through various computer means and recorded in a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, etc. alone or in combination. The program instructions recorded on the medium may be specially designed and configured for the present invention, or may be known and available to those skilled in the art of computer software. Examples of the computer-readable recording medium include magnetic media such as hard disks, floppy disks and magnetic tapes, optical media such as CD-ROMs and DVDs, and magnetic such as floppy disks. - includes magneto-optical media, and hardware devices specially configured to store and execute program instructions, such as ROM, RAM, flash memory, and the like. Examples of program instructions include not only machine language codes such as those generated by a compiler, but also high-level language codes that can be executed by a computer using an interpreter or the like. The hardware devices described above may be configured to operate as one or more software modules to perform the operations of the present invention, and vice versa.

Although the present invention has been described in detail with reference to preferred embodiments so far, the present invention is not limited to the above-described embodiments, and without departing from the gist of the present invention as claimed in the following claims, the technical field to which the present invention pertains It will be said that the technical idea of the present invention extends to the extent that any person with ordinary skill in the art can make various changes or modifications.

According to the precoding apparatus and the interference processing method of the precoding apparatus of the present invention, the interference processing method reflecting the reliability of the estimated channel of each terminal in a communication environment in which remote modules (RAU) and the terminal are located in the same space In that it is possible to calculate the precoding information for each remote module according to the It is an invention with industrial applicability because it can be implemented.

100: precoding device
10: generating unit 20: determining unit
30: classification unit 40: calculation unit

Claims (16)

a generator for generating integrated estimated channel information for each terminal from estimated channel information estimated for each terminal by two or more remote modules based on SRS (Sounding Reference Signal) signal quality;
a determining unit for determining the reliability of the estimated channel of each terminal from the integrated estimated channel information; and
A calculation unit for calculating integrated precoding information for each terminal according to a different interference processing method based on the reliability of the estimated channel determined for each terminal, slicing and transmitting the precoding information corresponding to each of the two or more remote modules, ,
The calculation unit,
When calculating the precoding vector for the UE of interest, the precoding vector is calculated so that orthogonality is established, and when the reliability of the estimated channel for the interfering UE that the UE of interest may interfere with is less than or equal to a threshold, the average interference power to be exerted on the interfering UE This is suppressed to be less than or equal to a certain value, and when the reliability of the estimated channel for the terminal of interest is less than or equal to a threshold, a precoding vector for suppressing the inter-layer interference power in the terminal of interest to be less than or equal to a certain value is calculated. precoding device. The method of claim 1,
The precoding device is
According to the reliability of the estimated channel determined for each terminal, the terminal is classified into at least one of a channel reliable group having a reliability equal to or higher than a threshold, and a channel unreliable group having a reliability lower than the threshold, and the interference processing method is determined according to the group classification result. Precoding device, characterized in that it further comprises a classification unit to be defined. The method of claim 1,
The determining unit,
A precoding apparatus, characterized in that the reliability of the estimated channel of each terminal is determined according to whether a signal-to-noise ratio (SNR) of an SRS signal received from each terminal exceeds a threshold value. delete The method of claim 1,
The calculation unit,
Precoding vector is calculated so that orthogonality of the estimated channel between the UE of interest and the interfering UE is established when the reliability of the estimated channel for both the UE of interest and the interfering UE that the UE of interest may interfere with is greater than or equal to a threshold coding device. delete The method of claim 1,
The calculation unit,
When the reliability of the estimated channel with respect to the UE of interest is equal to or greater than a threshold, the precoding apparatus characterized in that the precoding vector is calculated so that orthogonality between channels of layers in the UE of interest is established. The method of claim 1,
The calculation unit,
A precoding apparatus, characterized in that the precoding vector is calculated such that a ratio of noise generated due to a channel estimation error to signal power for a target layer of each terminal is maximized. ◈Claim 9 was abandoned when paying the registration fee.◈ In the interference processing method of a precoding device,
A generating step of generating integrated estimated channel information for each terminal from estimated channel information estimated for each terminal by two or more remote modules based on SRS (Sounding Reference Signal) signal quality;
a determination step of determining the reliability of the estimated channel of each terminal from the integrated estimated channel information; and
A calculation step of calculating the integrated precoding information for each terminal according to a different interference processing method based on the reliability of the estimated channel determined for each terminal, slicing it into the precoding information corresponding to each of the two or more remote modules, and delivering the calculation step and
The calculation step is
When calculating the precoding vector for the UE of interest, the precoding vector is calculated so that orthogonality is established, and when the reliability of the estimated channel for the interfering UE that the UE of interest may interfere with is less than or equal to a threshold, the average interference power to be exerted on the interfering UE This is suppressed to be less than or equal to a certain value, and when the reliability of the estimated channel for the terminal of interest is less than or equal to a threshold, a precoding vector for suppressing the inter-layer interference power in the terminal of interest to be less than or equal to a certain value is calculated. how to deal with interference. ◈Claim 10 was abandoned when paying the registration fee.◈ 10. The method of claim 9,
The method is
Prior to the calculation step, according to the reliability of the estimated channel determined for each terminal, the terminal is classified into at least one group of a channel reliable group having a reliability equal to or greater than a threshold, and a channel unreliable group having a reliability lower than the threshold, and the group classification result Interference processing method, characterized in that it further comprises a classification step for defining the interference processing method according to the. ◈Claim 11 was abandoned when paying the registration fee.◈ 10. The method of claim 9,
The determination step is
An interference processing method, characterized in that the reliability of the estimated channel of each terminal is determined according to whether a signal-to-noise ratio (SNR) of an SRS signal received from each terminal exceeds a threshold value. delete ◈Claim 13 was abandoned when paying the registration fee.◈ 10. The method of claim 9,
The calculation step is
Interference, characterized in that the precoding vector is calculated so that orthogonality of the estimated channel between the UE of interest and the interfering UE is established when the reliability of the estimated channel for both the UE of interest and the interfering UE capable of causing the interference is greater than or equal to a threshold processing method. delete ◈Claim 15 was abandoned when paying the registration fee.◈ 10. The method of claim 9,
The calculation step is
When the reliability of the estimated channel for the UE of interest is greater than or equal to a threshold, the method for processing interference, characterized in that the precoding vector is calculated so that the orthogonality between channels of the layers in the UE of interest is established. ◈Claim 16 was abandoned at the time of payment of the registration fee.◈ 10. The method of claim 9,
The calculation step is
An interference processing method, characterized in that the precoding vector is calculated so that the ratio of noise generated by a channel estimation error to signal power for a target layer of each terminal is maximized.

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