KR20170049134A - Base station device, and allocating method for wireless resource - Google Patents

Abstract

The present invention provides a base station device and a resource allocating method. The base station device is capable of using a common wireless resource to be used by each terminal more efficiently by selecting a combination of terminals including a terminal group for precoding a specific wireless resource among a plurality of terminals in a cell according to a multi user (MU)-multi input multi output (MIMO) method to maintain orthogonality between terminal signals so as to commonly allocate the precoded specific wireless resource, and another terminal for allocating the specific wireless resource to be overlapped with the terminal group according to a non-orthogonal multiple access (NOMA) method, and then by performing scheduling for allocating the specific wireless resource.

Description

[0001] Base Station Device and Resource Allocation Method [

The present invention relates to a method and apparatus for controlling a common wireless communication system in consideration of a data transmission rate difference between terminals caused by a distance difference between a base station apparatus and a terminal in a radio environment in which a non-orthogonal multiple access (NOMA) And more particularly to a scheduling method for more efficiently utilizing resources.

Non-orthogonal multiple access (NOMA) using superposition coding of a base station apparatus and SIC (successive interference cancellation) of a terminal is currently being studied in a wide range.

In the case of orthogonal frequency division multiple access (OFDMA), when a base station apparatus transmits a signal to a plurality of terminals, frequency orthogonality between signals is maintained.

On the other hand, in the non-orthogonal multiple access scheme using superposition coding, when a base station transmits signals to a plurality of terminals, the signals are transmitted in a manner that signals are superimposed on each other on the frequency axis.

If the transmission is performed using only superposition coding, it is impossible to demodulate the signals by overlapping the signals of the plurality of terminals. Therefore, the base station transmits the signals with different power ratios allocated to the terminals.

At this time, in the non-orthogonal multiple access scheme, a power ratio is generally allocated to a terminal closer to a base station apparatus and a terminal located farther away. The reason why the power ratio is distributed differently is that a nearby terminal uses SIC The user's signal must be removed.

Here, the SIC refers to a process of demodulating a signal received from the base station apparatus by demodulating and removing the signal of the other terminal.

In a non-orthogonal multiple access scheme, it is general that a signal-to-noise ratio (SINR) of a terminal performing an SIC is higher than a signal-to-noise ratio of a terminal not performing a SIC. Assuming that the amounts are similar, this difference in signal-to-noise ratio leads to a problem of how the base station apparatus allocates radio resources to the terminals.

Up to now, in most non-orthogonal multiple access schemes, the same amount of resource blocks (RBs) are allocated to both UEs based on fairness between UEs according to a PFS (Proportional Fair Scheduling) scheme.

However, the difference in the signal-to-noise ratio between terminals due to the difference in distance from the base station device leads to a difference in data rate between the respective terminals. Thus, the difference in the data rates is such that each terminal receives a large amount of data at the same time This is because it indicates whether there is.

Accordingly, it is possible to estimate that it is more efficient to allocate different amounts of radio resources (resource blocks, RBs) to each mobile station if the data request amount is similar between the mobile stations according to the distance difference from the base station.

As a result, in applying the non-orthogonal multiple access scheme, it is necessary to search a scheduling scheme to more efficiently utilize common radio resources to be used by each mobile station, considering the difference in data rate between the mobile stations according to the difference in distance from the base station I will do it.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a radio communication method and a radio communication method in a radio environment in which a non-orthogonal multiple access (NOMA) And to provide a scheduling scheme for more efficiently utilizing a common radio resource to be used by each terminal in consideration of a data transmission rate difference between the terminals.

According to an aspect of the present invention, there is provided a base station apparatus for transmitting a specific radio resource according to a first communication method among a plurality of terminals based on channel state information received from a plurality of terminals in a cell, A selection unit for selecting a combination of a terminal group for precoding and common assignment so that orthogonality is maintained between the terminal group and another terminal for overlapping allocation of the specific radio resource to the terminal group according to the second communication method; A discrimination unit for discriminating whether each terminal belonging to the terminal group can remove a signal of the other terminal received through the specific radio resource; And pre-coding the specific radio resource according to the first communication scheme and allocating the same precisely to each terminal belonging to the terminal group when it is determined that the signal of the other terminal can be removed, And allocating the specific radio resource to the other terminal by the terminal group in a redundant manner.

More specifically, the combination of the terminals is selected on the basis of information related to the path loss according to the distance from the base station apparatus in the channel state information.

More specifically, the selection unit determines that the path loss value is smaller than the other terminals among the plurality of terminals, and the difference between the path loss values of the respective terminals, And selects two or more terminals having a threshold value or less as the terminal group.

More specifically, when each of the terminals belonging to the terminal group measures a signal-to-noise ratio with respect to a signal of the other terminal, only when the measured signal-to-noise ratio is expected to be equal to or higher than the threshold value, It is determined that it can be removed after demodulating.

More specifically, the threshold value is a signal-to-noise ratio for supporting a data rate required by the other terminal.

More specifically, a signal-to-noise ratio measured with respect to a signal of the other terminal is expected to vary according to a ratio of transmission power between terminals belonging to the combination of the terminals.

According to an aspect of the present invention, there is provided a method for allocating resources according to a first communication method among a plurality of terminals based on channel state information received from a plurality of terminals in a cell, A combination of a terminal group for pre-coding and allocating resources in common for each terminal signal so that orthogonality is maintained between the terminal signals and a terminal composed of other terminals for allocating the specific radio resource to the terminal group in accordance with the second communication method ; Wherein the base station apparatus determines whether each terminal belonging to the terminal group can remove a signal of the other terminal received through the specific radio resource; And if the base station apparatus determines that it is possible to remove the signal of the other terminal, precodes the specific radio resource according to the first communication scheme and assigns it to each terminal belonging to the terminal group in common, And allocating the specific radio resource to the terminal group in a manner that the terminal group is allocated to the other terminal according to the second communication method.

More specifically, the combination of the terminals is selected on the basis of information related to the path loss according to the distance from the base station apparatus in the channel state information.

More specifically, in the selecting step, it is confirmed that the path loss value is smaller than the other terminals among the plurality of terminals, and the difference between the path loss values Is selected as the terminal group.

More specifically, in the determination step, when each of the terminals belonging to the terminal group measures a signal-to-noise ratio with respect to a signal of the other terminal, only when the measured signal-to- noise ratio is expected to be higher than or equal to a threshold value, It is determined that the signal can be removed after demodulating the signal.

Accordingly, in the base station apparatus and the resource allocation method according to an embodiment of the present invention, a specific radio resource is orthogonalized according to an MU (Multi User) -MIMO (Multiple Input Multi Output) scheme among a plurality of terminals in a cell A terminal group for pre-coding and allocating a common radio resource to the terminal group in accordance with a non-orthogonal multiple access (NOMA) scheme; As the scheduling for allocating the specific radio resources is performed by selecting a combination, an effect of increasing the data throughput and cell capacity of the UE in the cell is achieved.

1 is an exemplary diagram illustrating a wireless environment according to an embodiment of the present invention;
FIG. 2 is an exemplary diagram for explaining a transmission power ratio according to an embodiment of the present invention; FIG.
3 is an exemplary diagram for explaining a transmission power and a resource allocation method in a frequency axis according to an embodiment of the present invention;
FIG. 4 is an exemplary diagram illustrating a resource allocation method according to an embodiment of the present invention; FIG.
FIG. 5 is an exemplary diagram illustrating a configuration of a base station apparatus according to an embodiment of the present invention; FIG.
FIG. 6 is an exemplary diagram for explaining allocation of radio resources to a combination of terminals according to an embodiment of the present invention; FIG.
7 is a diagram for explaining an operation flow in a base station apparatus according to an embodiment of the present invention;

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

1 illustrates a wireless environment according to an embodiment of the present invention.

1, a base station apparatus 10 and a plurality of terminals UE0, UE1, UE2, UE3, ..., and UEN located in a cell C are connected to a radio environment according to an embodiment of the present invention. .

The base station apparatus 10 includes a cell C and a base station for providing a mobile communication service to a plurality of terminals UE0, UE1, UE2, UE3, ..., and UEN located in the cell C For example, a NodeB and an eNodeB.

In the case of UEs UE0, UE1, UE2, UE3,..., And UEN, mobile or fixed user nodes such as User Equipment (UE) and Mobile Station (MS)

The radio environment according to an embodiment of the present invention may follow a non-orthogonal multiple access scheme such as a Non-Orthogonal Multiple Access (NOMA) technique for the purpose of increasing frequency capacity in a cell.

As described above, the non-orthogonal multiple access scheme uses a superposition coding function of the base station apparatus 10 to transmit signals to a plurality of terminals in a manner that signals overlap each other on the frequency axis .

When transmission is performed using only superposition coding, it is impossible to demodulate the signals by overlapping the signals of the plurality of terminals. Therefore, the base station apparatus 10 transmits the signals with different power ratios allocated to the terminals.

At this time, in general, the base station apparatus 10 allocates a low power ratio to terminals located closer to the distant terminal. The reason why the power ratio is distributed differently is that a nearby terminal uses SIC (Successive Interference Cancellation) Thereby removing the signal of the user located far away.

In this regard, FIG. 2 shows an example in which the base station apparatus 10 assigns a different transmission power ratio to each terminal.

Referring to FIG. 2, it can be seen that the transmission power ratio of the terminal UE1 closer to the base station apparatus 10 is allocated to the base station apparatus 10 than the UE2 which is a far-away terminal.

FIG. 3 shows a comparison between the transmission power in the orthogonal frequency division multiplexing access (OFDMA) scheme and the non-orthogonal multiple access technique and the resource allocation scheme in the frequency axis.

Referring to FIG. 3, in the application of the non-orthogonal multiple access scheme, the UE 1, which is a terminal located close to the base station apparatus 10, uses the SIC to demodulate the signal, While the UE2 does not use the SIC.

In case of the UE 1, the signal of the UE 2 is demodulated before using the SIC, and this signal is removed from the original signal, leaving only the signal of the UE 1. If this process is performed, the interference is eliminated in the UE 1 and the signal to noise ratio ) Is improved.

On the other hand, since the UE 2 does not use the SIC, it attempts demodulation by using the signal transmitted from the base station apparatus 10 as a general signal demodulation situation without any processing. The reason why the UE 2 does not attempt SIC is that, (10) There is a reason for the allocated transmission power ratio.

That is, in order for the user to try SIC, the intensity of the interference signal should be higher than a certain threshold value, and it is much easier and more realistic to demodulate the stronger signal than to demodulate the weak signal.

For example, the reason for the SIC of the UE 1 is that the base station device 10 has assigned a higher power ratio to the UE 2 located relatively farther from the UE 1, and when a signal sent from the base station device 10 in the UE 1 position reaches, SIC is possible because the intensity is stronger than the intensity of the UE1 signal.

On the other hand, in order for the UE 2 to perform the SIC, the strength of the signal of the UE 1 should be stronger than that of the UE 2, but since the strength of the UE 2 is greater than the strength of the signal of the UE 1, the SIC can not be performed. will be.

In such a non-orthogonal multiple access scheme, it is general that the signal-to-noise ratio (SINR) of the terminal performing the SIC is higher than the signal-to-noise ratio of the terminal not performing the SIC.

Assuming that the amounts of data requested by the two terminals are similar, the difference in the signal-to-noise ratio leads to a problem of how the base station 10 allocates radio resources to the terminals.

On the other hand, in the non-orthogonal multiple access scheme, it is general to allocate the same amount of radio resource (RB) to both UEs based on fairness between UEs according to a PFS (Proportional Fair Scheduling) scheme.

However, the difference in the signal-to-noise ratio between the terminals due to the difference in distance from the base station apparatus 10 leads to a difference in data rates of the respective terminals. The difference in the data rates is caused by how much data It is because it shows whether it can receive.

In this regard, FIG. 4 shows an example of a resource allocation scheme according to an embodiment of the present invention.

4A, the UE 1 and the base station 10, which are located close to the base station 10 and perform the SIC, are positioned relatively far away from each other and are located in the SIC It is possible to confirm that the same amount of radio resources are allocated to the UE 2 which is a terminal that does not perform the radio resource allocation.

In this case, rather than allocating the same amount of radio resources to the UE1 and the UE2 in which the data rate difference due to the difference in distance from the base station apparatus 10 occurs, It would be ideal to allocate radio resources non-uniformly considering the data transmission rate.

However, when the wireless resources are non-uniformly allocated to the two terminals in consideration of the respective data transmission rates, there is a problem in how to utilize the remaining wireless resources in the area shown in (b) of FIG. 5 do.

As a result, when a different amount of radio resources is allocated to each terminal in consideration of a data rate difference between terminals, which may occur due to a difference in distance between the base station apparatus 10 and a terminal in a radio environment to which a non-orthogonal multiple access scheme is applied It is necessary to further solve the problem of how to utilize the remaining radio resources in the (2) area.

5 (b), considering the difference in data rates between the respective terminals caused by the difference in distance between the base station apparatus 10 and the terminals in the radio environment to which the non-orthogonal multiple access scheme is applied, Hereinafter, a configuration of the base station apparatus 10 for implementing the radio resource efficiently will be described in detail.

Meanwhile, the base station apparatus 10 according to an embodiment of the present invention is a method for efficiently allocating different amounts of radio resources to each terminal, and is a method for efficiently allocating different amounts of radio resources to each terminal by using a MU (Multi User) -MIMO (Multi Input Multi Output) The MU-MIMO scheme will be described before a specific description of the base station apparatus 10 will be given.

Unlike the SU (Single User) -MIMO (Multi Input Multi Output) scheme, which allocates radio resources, i.e., time-frequency resources, to one UE, the MU- And allocates them precisely to a plurality of terminals in common.

In order to properly demodulate the data mixed and transmitted in the same time-frequency resource at each terminal, the signals transmitted from the base station apparatus 10 must have orthogonality. The orthogonality of the signals is MU-MIMO precoding, .

In this regard, the operation in the general MU-MIMO scheme can be performed through the following process.

First, when the base station apparatus 10 transmits a reference signal (RS) to each terminal in the cell C, each terminal in the cell C transmits channel state information (CSI) Information to the base station apparatus 10.

On the other hand, the base station apparatus 10 calculates an MU-MIMO precoding matrix using channel state information received from each terminal in the cell C, As a result, it is possible to select a terminal group capable of maximizing the performance of the cell (C) among the MU-MIMO precoding matrices.

Then, the BSC 10 simultaneously allocates the time-frequency resources to each MS belonging to the selected MS.

The MU-MIMO scheme used together with the non-orthogonal multiple access scheme will now be described with reference to the configuration of the base station apparatus 10.

FIG. 5 shows a configuration of a base station apparatus 10 according to an embodiment of the present invention.

5, the base station apparatus 10 according to an exemplary embodiment of the present invention pre-codes specific radio resources according to an MU-MIMO scheme (first communication scheme) so that orthogonality between terminal signals is maintained, (11) for selecting a combination of a terminal group for assigning a specific radio resource to a terminal group and a terminal for other terminals for assigning a specific radio resource to the terminal group according to a non-orthogonal multiple access method (second communication method) A discriminator 12 for discriminating whether each terminal belonging to a combination of terminals can remove a signal of another terminal and an allocator 13 for allocating a specific radio resource to each terminal belonging to a combination of terminals according to the discrimination result Configuration.

Here, the fact that each terminal belonging to the terminal group can remove the signal of the other terminal means that each terminal belonging to the terminal group can be located close to the base station apparatus 10 and use the SIC. In the case of the UE, the UE is located farther away from the Node B than the UE, so that the SIC is not used.

The entire configuration or at least a part of the base station apparatus 10 including the selecting unit 11, the determining unit 12 and the assigning unit 13 may be implemented in the form of a software module or a hardware module, And can be implemented in a combined form.

As a result, the base station apparatus 10 according to an embodiment of the present invention calculates the difference between the data rate of each terminal due to the difference in distance between the base station apparatus 10 and the terminal in the radio environment to which the non-orthogonal multiple access scheme is applied, , It is possible to efficiently allocate different amounts of radio resources to the respective terminals. Hereinafter, each configuration in the base station apparatus 10 for realizing the same will be described in more detail.

The base station apparatus 10 transmits a reference signal RS (RS) to a plurality of terminals UE0, UE1, UE2, UE3, ..., and UEN located in the cell C, The base station apparatus 10 receives the channel state information (CSI) from a plurality of UEs UE0, UE1, UE2, UE3, ..., and UEN by transmitting a reference signal.

6, UE1, UE2, and UE3 among the plurality of terminals UE0, UE1, UE2, UE3, ..., and UEN in the cell C It is assumed that a combination of terminals according to an embodiment of the present invention is selected and specific radio resources are allocated.

Here, UE1 is a terminal located relatively close to the base station apparatus 10, and UE3 is a terminal located relatively far from the base station apparatus 10, as in the non-orthogonal multiple access scheme.

In addition, U3 is a UE located relatively close to the base station 10 as UE1, and it can be expected that radio resources remaining in the (2) region can be allocated to U3.

The selection unit 11 performs a function of selecting a combination of terminals for allocating specific radio resources.

More specifically, the selector 11 selects one of the plurality of terminals UE0, UE1, ..., UE2 using the channel state information received from the plurality of terminals UE0, UE1, UE2, UE3, UE2, UE3, ..., and UEN according to a MU-MIMO scheme, the terminal groups for pre-coding specific radio resources to maintain orthogonality among the respective terminal signals and allocating them in common, And selects a combination of terminals composed of other terminals for redundantly allocating resources to the terminal group.

At this time, the selector 11 pre-codes UE1 and UE3, which are located relatively close to the base transceiver station 10, according to the MU-MIMO scheme so that orthogonality is maintained between the respective terminal signals, And can select a UE, which is a terminal located relatively far away from the base station apparatus 10, as a terminal for redundantly allocating the specific radio resource to the terminal group according to a non-orthogonal multiple access scheme.

Although the terminals belonging to the terminal group are exemplified as two terminals UE1 and UE3, the terminal capable of SIC, which will be described below, is not limited to the terminal groups of the terminal groups for allocating specific radio resources in common according to the MU- Of course.

In this regard, in selecting a combination of terminals, the selecting unit 11 selects one of a plurality of terminals (UE0, UE1, UE2, UE3, ..., and UEN) By allocating different MU-MIMO precoding-related codebooks, non-orthogonal MIMO-related precoding-related codebooks, and different transmission power ratios for each terminal in a combination of terminals for each combination of terminals, A combination of terminals that can guarantee the maximum data rate of the mobile station C can be selected.

Here, the sum of the transmission power allocated to each terminal in the combination of the terminals should not exceed the maximum transmission power supported by the base station apparatus 10.

For reference, the selection operation of combinations of the above terminals can be performed, for example, through the syntax up to the underlined portion in Step 3 of the following [Algorithm 1].

[Algorithm 1]

Step 0:

Assume BS select 3 users for proposed scheme

)Assume N Users exist in cell, (

)

Step 1 : Base station (BS) transmits Reference Signal

Step 2 : All users in cell feedback CSI to BS

Step 3 : For i = 1, ..., N

: set of MU-MIMO pair except

Define

: set of MU-MIMO pair except

For j = 1, ...,

and

For all codebook for

and

For  all available power ratio set

If

and

Store

and

End if

End for

End for

End for

End for

Step 4 : BS transmit signal using above optimal solution

는 Kx2 행렬이며 행의 원소수는

이다. Step 2의

는 SIC를 수행하지 않고 기지국장치(10)으로부터 비직교 다중접속 방식에 따라 무선자원이 할당되는 타 단말을 뜻한다. Step3의 마지막 식은 셀의 데이터전송률을 최대로 하는 코드북과 단말의 조합을 가려내는 과정이다.here,

Is a Kx2 matrix and the number of elements in the row is

to be. Step 2 of

Refers to another terminal to which a radio resource is allocated according to a non-orthogonal multiple access scheme from the base station apparatus 10 without performing SIC. The last equation of Step 3 is a process of extracting a combination of a codebook and a terminal that maximizes a data rate of a cell.

The selection operation for combination of the above terminals performed by the selection unit 11 is a combination of a plurality of terminals with arbitrary terminals and sets all codebooks and all transmission power ratios However, in the case of considering the number of all cases, there is a problem that much time is consumed even if the performance of the base station apparatus 10 is high.

Furthermore, if the number of terminals in the cell C increases, the number of combinations of terminals that can be configured in any terminal also increases, and the number of cases in which consideration is required to select a terminal combination increases exponentially, The above problem can be expected to be further intensified.

As a result, such a problem is included in the number of cases in which even a terminal that can not serve the MU-MIMO scheme can be configured as a terminal group in configuring an arbitrary terminal group related to the MU-MIMO scheme in the combination of terminals .

In order to solve such a problem, the base station apparatus 10 according to an embodiment of the present invention constructs an arbitrary terminal group related to the MU-MIMO scheme in the combination of terminals, The number of cases in which an arbitrary terminal group can be configured is reduced.

In this regard, the selection unit 11 selects a terminal group related to the MU-MIMO scheme based on information (e.g., RSRP) related to the path loss according to the distance from the base station apparatus 10 in the channel state information.

That is, the selecting unit 11 selects a terminal having a smaller path loss value than the other terminals selected in relation to the non-orthogonal multiple access method among the terminals UE0, UE1, UE2, UE3, ..., and UEN in the cell C. [ The number of cases in which an arbitrary terminal group can be configured can be reduced by configuring an arbitrary terminal group related to the MU-MIMO scheme only by the terminal group.

Here, the fact that the path loss value is smaller than that of the other terminals selected in relation to the non-orthogonal multiple access scheme means that the distance from the base station apparatus 10 is closer to that of the other terminals.

Also, the selecting unit 11 selects one of the plurality of terminals UE0, UE1, UE2, UE3, ..., and UEN in the cell C, The number of cases in which an arbitrary terminal group can be configured is further restricted by configuring the terminal group only with terminals whose difference between the path loss values is less than or equal to the threshold value.

Here, if the path loss value between the terminals is less than the threshold value, the distance between the two terminals is close to that of the other terminal. If one terminal in the terminal group is capable of demodulating the other terminal signals , It means that other terminals in the same terminal group can also demodulate other terminal signals.

For reference, the value of the upper threshold for determining whether demodulation is possible for the other terminal signals in the terminal group is as follows. If the ratio of the transmission power used in the non-orthogonal multiple access scheme is very fine, If, on the other hand, the ratio of the transmit power is not precise, the value may be relatively large.

For reference, the selection operation of combinations of the above terminals can be performed, for example, through the syntax up to the underlined part in Step 6 of the following [Algorithm 2].

[Algorithm 2]

Step 0:

Assume BS select 3 users for proposed scheme

)Assume N Users exist in cell, (

)

Step 1 : Base station (BS) transmits Reference Signal

Step 2 : All users in cell feedback CSI to BS

Step 3 : For i = 1 ... N

: set of MU-MIMO pair except

Step 4 : Define

: set of MU-MIMO pair except

Step 5 :

Step 6 :

For j = 1 ... A

and

For all codebook for

and

For  all available power ratio set

If

and

Store

and

End if

End for

End for

End for

End for

Step 7 : BS transmit signal using sub-optimal solution

는 사용자

보다 경로손실이 작은 MU-MIMO 관련 단말 그룹의 집합을 말한다. 따라서

는 Tx2 행렬로 T개의 경우의 수에 대한 단말의 집합을 말하며

의 행의 원소수는

이다. Step6에서 집합

에 속한 두 단말의 기지국장치(10)로부터의 경로손실 차이가

이하일 때, MU-MIMO 관련 단말 그룹으로 선정 된 Ax2 행렬을

라 하면,

의 행의 원소수

이다.Here, in Step 5

User

And MU-MIMO-related terminal groups having a smaller path loss than the terminal groups. therefore

Is a Tx2 matrix and refers to a set of terminals for the number of T cases

The number of rows in

to be. In Step 6 ,

The difference in path loss from the base station apparatus 10 of the two terminals belonging to the

, An Ax2 matrix selected as an MU-MIMO terminal group

In other words,

The number of columns in the row

to be.

MU-MIMO scheme related to selection of the terminal group, why into a condition less than the path loss of the Non-SIC UE as Step5 is not performing SIC than the terminal to perform SIC at a non-orthogonal multiple access techniques As previously mentioned, This is because the distance of the terminal from the base station apparatus 10 is near.

보다 크지 않다라는 조건을 넣었다.In addition, in Step 6 , when selecting an MU-MIMO related terminal group, the difference in path loss between the two terminals

But not more than that.

The reason for adding this condition is that, when the MU-MIMO UEs perform the SIC, if a user having a large path loss among the two users can demodulate the signal of the UE2 according to the non-orthogonal multiple access scheme, Is also likely to successfully demodulate the signal of UE2.

As a result, the terminal groups that can not pass the SIC condition can be removed in advance through this condition.

값은 시스템에 따라 변동이 있을 수 있다. 만약 비 직교 다중 접속 방식에 사용되는 전력 비율 set이 매우 세밀하게 구성되어 있다면

값은 커도 상관이 없을 것이다. 반대로 전력 비율 set이 세밀하지 못하다면

값은 작아야 한다.And

Values may vary from system to system. If the power ratio set used for the non-orthogonal multiple access scheme is very fine-grained

The value will not matter. Conversely, if the power ratio set is not granular

The value should be small.

The determination unit 12 performs a function of determining whether or not each terminal belonging to the terminal group can remove the signal of the other terminal.

More specifically, when the selection of the combination of the terminal groups UE1 and UE3 related to the MU-MIMO scheme and the terminal composed of the other terminals UE2 related to the non-orthogonal multiple access method is completed, It is determined whether or not each terminal belonging to the UEs UE1 and UE3 can remove the signal of the UE2 related to the non-orthogonal multiple access scheme.

The reason that each terminal belonging to the terminal groups UE1 and UE3 removes the signal of the other terminal UE2 related to the non-orthogonal multiple access scheme is that the terminals belonging to the terminal groups UE1 and UE3, Lt; RTI ID = 0.0 > SIC < / RTI >

In this case, when the signal-to-noise ratio of each terminal belonging to the terminal groups UE1 and UE3 is measured in relation to the signal of the other terminal UE2, the determination unit 12 may determine that the measured signal- , It can be determined that the signal of the other terminal UE2 can be removed.

Here, the threshold value of the signal-to-noise ratio used to determine whether to remove the signal from the other terminal can be determined to be a value greater than or equal to a minimum signal-to-noise ratio capable of supporting a data rate required by the other terminal.

That is, the measured signal-to-noise ratio of the signal of the other terminal, which is received at each terminal belonging to the terminal groups UE1 and UE3, is equal to or higher than the threshold value, it is possible to guarantee the data rate required by the other terminal UE2, It means that each terminal belonging to the terminal groups UE1 and UE3 can normally demodulate and remove signals of the other terminal.

The signal-to-noise ratios measured in relation to the signals of the other terminals in the terminals belonging to the terminal groups UE1 and UE3 may be estimated differently depending on the transmission power ratios allocated to the terminals belonging to the terminal groups UE1 and UE3 For example, if the allocated transmission power ratio is low, then the signal-to-noise ratio is predicted to be low, and conversely if the allocated transmission power ratio is large, the signal-to-noise ratio can be predicted to be large.

For reference, the operation of discriminating whether or not the other terminal signals made by the discrimination unit 12 can be removed is performed through the following equations commonly included in Step 3 of [Algorithm 1] and Step 6 of [Algorithm 2] Can be expressed.

""If

"

The assigning unit 13 performs a function of assigning a specific radio resource to each terminal.

More specifically, when it is determined that the terminals belonging to the terminal groups UE1 and UE3 can remove the signals of the other terminals, the assigning unit 13 assigns MUs to the terminals belonging to the terminal groups UE1 and UE3, -MIMO scheme and allocates specific radio resources to the terminal group in accordance with the non-orthogonal multiple access scheme for the other terminal UE2.

As described above, according to the base station apparatus 10 according to an embodiment of the present invention, among the UEs UE0, UE1, UE2, UE3, ..., and UEN in the cell C, A terminal group for pre-coding and allocating a specific radio resource to orthogonality between each terminal signal so as to maintain orthogonality, and a terminal for overlapping allocation of the specific radio resource to the terminal group according to a non-orthogonal multiple access method The number of terminals capable of allocating a limited radio resource in the cell C is increased by selecting a combination of terminals and allocating the specific radio resources to increase the data throughput of the terminal in the cell C and the capacity Can be achieved.

Hereinafter, the operation of the base station apparatus 10 according to an embodiment of the present invention will be described with reference to FIG. 7, after the description of the configuration of the base station apparatus 10 according to an embodiment of the present invention .

FIG. 7 is a flowchart illustrating an operation flow in the base station apparatus 10 according to an embodiment of the present invention.

First, the selector 11 selects channel state information received from a plurality of UEs UE0, UE1, UE2, UE3, ..., and UEN in the cell C according to steps S10 to S40, A terminal group for pre-coding and allocating specific radio resources among a plurality of terminals UE0, UE1, UE2, UE3, ..., and UEN according to MU-MIMO scheme to maintain orthogonality among terminal signals, And selects a combination of terminals composed of other terminals for redundantly allocating the specific radio resource to the terminal group according to the multiple access method.

In this regard, in selecting a combination of terminals, the selecting unit 11 selects one of a plurality of terminals (UE0, UE1, UE2, UE3, ..., and UEN) By allocating different MU-MIMO precoding-related codebooks, non-orthogonal MIMO-related precoding-related codebooks, and different transmission power ratios for each terminal in a combination of terminals for each combination of terminals, A combination of terminals that can guarantee the maximum data rate of the mobile station C can be selected.

At this time, the selector 11 confirms the information (e.g., RSRP) related to the path loss according to the distance from the base station apparatus 10 in the channel state information according to step 'S10', so that the terminal unit 11 related to the MU- .

In this regard, the selecting unit 11 selects the other one of the plurality of UEs UE0, UE1, UE2, UE3, ..., and UEN in the cell C according to the non-orthogonal multiple access scheme By configuring an arbitrary terminal group related to the MU-MIMO scheme only with terminals having a smaller path loss value than the terminal, the number of cases in which an arbitrary terminal group can be configured is reduced.

Here, the fact that the path loss value is smaller than that of the other terminals selected in relation to the non-orthogonal multiple access scheme means that the distance from the base station apparatus 10 is closer to that of the other terminals.

In addition, the selecting unit 11 may select one of the plurality of terminals UE0, UE1, UE2, UE3, ..., and UEN in the cell C in accordance with the non-orthogonal multiple access method The number of cases in which an arbitrary terminal group can be configured is further restricted by configuring the terminal group only with terminals whose difference in path loss value among the terminals with the smallest path loss value is equal to or less than the threshold value.

Here, if the path loss value between the terminals is less than the threshold value, the distance between the two terminals is close to that of the other terminal. If one terminal in the terminal group is capable of demodulating the other terminal signals , It means that other terminals in the same terminal group can also demodulate other terminal signals.

When the selection of the combination of the terminal groups UE1 and UE3 related to the MU-MIMO scheme and the terminal composed of the other terminals UE2 related to the non-orthogonal multiple access method is completed, the determination unit 12 proceeds to step S50 ' Determines whether or not each terminal belonging to the terminal groups UE1 and UE3 can remove the signal of the other terminal UE2 related to the non-orthogonal multiple access method.

The reason that each terminal belonging to the terminal groups UE1 and UE3 removes the signal of the other terminal UE2 related to the non-orthogonal multiple access scheme is that the terminals belonging to the terminal groups UE1 and UE3, Lt; RTI ID = 0.0 > SIC < / RTI >

In this case, when the signal-to-noise ratio of each terminal belonging to the terminal groups UE1 and UE3 is measured in relation to the signal of the other terminal UE2, the determination unit 12 may determine that the measured signal- , It can be determined that the signal of the other terminal UE2 can be removed.

Here, the threshold value of the signal-to-noise ratio used to determine whether to remove the signal from the other terminal can be determined to be a value greater than or equal to a minimum signal-to-noise ratio capable of supporting a data rate required by the other terminal.

That is, the measured signal-to-noise ratio of the signal of the other terminal received at each terminal belonging to the terminal groups UE1 and UE3 is equal to or higher than the threshold value, which can guarantee the data rate required by the terminal. , UE3 can normally demodulate and remove signals from other terminals.

The signal-to-noise ratios measured in relation to the signals of the other terminals in the terminals belonging to the terminal groups UE1 and UE3 may be estimated differently depending on the transmission power ratios allocated to the terminals belonging to the terminal groups UE1 and UE3 For example, if the allocated transmission power ratio is low, then the signal-to-noise ratio is predicted to be low, and conversely if the allocated transmission power ratio is large, the signal-to-noise ratio can be predicted to be large.

If it is determined that the terminals belonging to the terminal groups UE1 and UE3 can remove the signals of the other terminals, the allocating unit 13 determines whether or not each terminal belonging to the terminal groups UE1 and UE3 Specific radio resources are allocated to the UE in common according to the MU-MIMO scheme, and a specific radio resource is allocated to the UEs (UE2) in a redundant manner according to a non-orthogonal multiple access scheme.

As described above, according to the operation flow in the base station apparatus 10 according to the embodiment of the present invention, among the plurality of terminals UE0, UE1, UE2, UE3, ..., and UEN in the cell C, A terminal group for pre-coding specific radio resources according to a MIMO scheme so that orthogonality is maintained between respective terminal signals and allocating them in common, and a terminal group for assigning the specific radio resources to the terminal group redundantly according to a non- The number of terminals capable of allocating a limited radio resource in the cell C is increased by selecting a combination of terminals including the terminal and allocating the specific radio resources to increase the data throughput of the terminal in the cell C, (C) the effect of increasing the capacity is achieved.

Meanwhile, the steps of a method or algorithm described in connection with the embodiments disclosed herein may be embodied directly in hardware, or may be embodied in a computer readable medium, in the form of a program instruction, which may be carried out through various computer means. The computer-readable medium may include program instructions, data files, data structures, and the like, alone or in combination. The program instructions recorded on the medium may be those specially designed and configured for the present invention or may be available to those skilled in the art of computer software. Examples of computer-readable media include magnetic media such as hard disks, floppy disks and magnetic tape; optical media such as CD-ROMs and DVDs; magnetic media such as floppy disks; Magneto-optical media, and hardware devices specifically configured to store and execute program instructions such as ROM, RAM, flash memory, and the like. Examples of program instructions include machine language code such as those produced by a compiler, as well as high-level language code 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.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention.

According to the base station apparatus and the resource allocation method according to the present invention, when a non-orthogonal multiple access (NOMA) scheme is applied to a cell, a data rate Considering the difference, scheduling is carried out in order to more efficiently utilize common radio resources to be used by each mobile station. Therefore, as the mobile station has exceeded the limitations of the prior art, Or is likely to be industrially applicable because it is capable of being practically and practically obvious.

10: base station device
11: Decision section 12: Transmission section
13: Receiving unit 14:
15:
20: terminal
21: Receiving unit 22:
23:

Claims (10)

A terminal group for pre-coding and allocating common radio resources to orthogonality between terminal signals according to a first communication method among the plurality of terminals based on channel state information received from a plurality of terminals in a cell, A selection unit configured to select a combination of terminals including other terminals for redundantly allocating the specific radio resource to the terminal group according to a second communication scheme;
A discrimination unit for discriminating whether each terminal belonging to the terminal group can remove a signal of the other terminal received through the specific radio resource; And
If it is determined that the signal of the other terminal can be removed, precodes the specific radio resource according to the first communication scheme and assigns the common radio resource to each terminal belonging to the terminal group in common, And allocating the specific radio resource to the other terminal to the terminal group in a redundant manner. The method according to claim 1,
In the combination of the terminals,
Wherein the channel state information is selected based on information related to a path loss according to a distance from the base station apparatus in the channel state information. 3. The method of claim 2,
Wherein the selection unit comprises:
Wherein the path loss value is smaller than the other terminals among the plurality of terminals and that the difference between the path loss values of the terminals is less than the threshold value, Group as a group. The method according to claim 1,
Wherein,
When each of the terminals belonging to the terminal group measures a signal-to-noise ratio in relation to the signal of the other terminal, only when the measured signal-to-noise ratio is expected to be equal to or higher than the threshold value, The base station apparatus comprising: 5. The method of claim 4,
The threshold value may be,
And a signal-to-noise ratio to support a data rate required by the other terminal. 5. The method of claim 4,
The signal-to-noise ratio, measured in relation to the signal of the other terminal,
And estimates differently according to a ratio of transmission power between each terminal belonging to a combination of the terminals. A base station apparatus includes a terminal for pre-coding specific radio resources according to a first communication scheme of the plurality of terminals to maintain orthogonality between terminal signals based on channel state information received from a plurality of terminals in a cell, Selecting a combination of terminals and a terminal composed of other terminals for redundantly allocating the specific radio resources to the terminal group according to a second communication scheme;
Wherein the base station apparatus determines whether each terminal belonging to the terminal group can remove a signal of the other terminal received through the specific radio resource; And
When the base station apparatus determines that the signal of the other terminal can be removed, precodes the specific radio resource according to the first communication scheme and assigns it to each terminal belonging to the terminal group in common, And allocating the specific radio resource to the other terminal according to a second communication scheme in a manner of redundantly assigning the specific radio resource to the terminal group. 8. The method of claim 7,
In the combination of the terminals,
Wherein the channel state information is selected based on information related to a path loss according to a distance from the base station apparatus in the channel state information. 9. The method of claim 8,
In the selecting step,
Wherein the path loss value is smaller than the other terminals among the plurality of terminals and that the difference between the path loss values of the terminals is less than the threshold value, And selecting the group as a group. 8. The method of claim 7,
Wherein,
When each of the terminals belonging to the terminal group measures a signal-to-noise ratio in relation to the signal of the other terminal, only when the measured signal-to-noise ratio is expected to be equal to or higher than the threshold value, The resource allocation method comprising the steps of:

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