KR20220049852A - Method and apparatus for allocating frequency to plurality of links - Google Patents

Abstract

The present invention relates to a method for frequency allocation to links, which includes the following steps of: allocating a first frequency band to a first link, which is one of links and has a maximum SINR when the first frequency band is allocated, and adding the first link to a first group including frequency-allocated links; calculating the SINR in the event of first frequency band allocation with respect to the links other than the link included in the first group in view of interference attributable to the link included in the first group and determining a second group based on the calculation result; calculating a minimum SINR margin value of the link included in the first group when the first frequency band is allocated to the link included in the second group; and allocating, based on the calculation result, the first frequency band to the link that is included in the second group and provides the largest minimum SINR margin value to the link in the first group.

Description

METHOD AND APPARATUS FOR ALLOCATING FREQUENCY TO PLURALITY OF LINKS

The present disclosure relates to an apparatus and method for allocating frequencies to a plurality of links.

As wireless communication technology develops, the number of wireless terminals including radars, sensors, satellites, and wireless equipment including mobile communication terminals is rapidly increasing. Accordingly, the demand for frequencies allocated to wireless terminals rapidly increases, and research on a frequency allocation technique that can efficiently use a limited frequency while satisfying the service requirements of each terminal is in progress.

Recent frequency allocation techniques include those based on optimization algorithms and machine learning algorithms, but these techniques have high computational complexity and a long time required for the algorithm. Therefore, considering the dynamic characteristics of the network, it may be difficult to apply in practice, and there may be cases in which an actual optimal solution cannot be found.

Accordingly, there is a need for a method for efficiently allocating a limited frequency to a link with low computational complexity.

An object of the present embodiment is to provide a method and apparatus for allocating frequencies so that a plurality of links use overlapping frequencies while satisfying a predetermined SINR or higher.

The technical problems to be achieved by the present embodiment are not limited to the technical problems described above, and other technical problems may be inferred from the following embodiments.

According to the first embodiment, in a method of allocating frequencies to a plurality of links, a first frequency band is allocated to a first link having a maximum SINR when a first frequency band is allocated among a plurality of links, and the first link adding to a first group consisting of links to which frequencies have already been assigned, in consideration of interference caused by links included in the first group, a first frequency band is allocated to the remaining links except for the links included in the first group calculating the SINR when the first frequency band is allocated and determining the second group based on the calculation result. When the first frequency band is allocated to the link included in the second group, The method may include allocating the first frequency band to a link that provides the largest SINR margin minimum value to the first group link among the links included in the second group based on the calculating step and the calculation result.

According to the second embodiment, an apparatus for allocating frequencies to a plurality of links includes a memory storing at least one instruction and executing the at least one instruction to select a first frequency band among the plurality of links. allocating the first frequency band to the first link having the maximum SINR when assigned SINR when the first frequency band is allocated for the remaining links except for links included in the first group in consideration of the calculation result, a second group is determined based on the calculation result, When 1 frequency band is allocated, the minimum SINR margin value of the links included in the first group is calculated, and based on the calculation result, the largest SINR margin minimum value is provided to the links in the first group among the links included in the second group It may include a processor for allocating the first frequency band to the link.

According to the third embodiment, a computer-readable recording medium is a computer-readable non-transitory recording medium recording a program for executing a method of allocating frequencies to a plurality of links in a computer, and is a non-transitory computer-readable recording medium in which the frequency is assigned to the plurality of links. The method of allocating is a method of allocating a first frequency band to a first link having a maximum SINR when a first frequency band is allocated among a plurality of links, and assigning the first frequency band to a first group consisting of links to which frequencies are already assigned. adding to , calculating the SINR when the first frequency band is allocated for the remaining links except for the link included in the first group in consideration of interference due to the link included in the first group, and based on the calculation result to determine the second group, calculating the minimum SINR margin value of the link included in the first group when the first frequency band is allocated to the link included in the second group, and based on the calculation result, the second group The method may include allocating a first frequency band to a link that provides the largest SINR margin minimum value to the first group link among the links included in the group.

Specific details of other embodiments are included in the detailed description and drawings.

The frequency allocation method and apparatus according to the present disclosure can reduce the overall frequency bandwidth allocated to a plurality of links while ensuring a signal-to-interference-plus-noise ratio (SINR) required for each link. In addition, since it is based on a greedy algorithm, which is one of the heuristic algorithms, the computational complexity may be lower than that of an optimization or machine learning-based algorithm, and the frequency of assigning a frequency may be faster.

Effects of the invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims.

1 is a diagram for explaining a wireless network system that can be applied to an embodiment of the present invention.
2 is a flowchart illustrating a method of allocating frequencies to a plurality of links according to an embodiment.
3 is a flowchart illustrating a method of allocating frequencies to a plurality of links according to another embodiment.
4 is a diagram for explaining an overlapping frequency interference index model according to an embodiment.
5 to 7 are diagrams for explaining the performance of a frequency allocating apparatus according to an embodiment.
8 is a block diagram illustrating an apparatus for allocating a frequency according to an embodiment.

Terms used in the embodiments are selected as currently widely used general terms as possible while considering functions in the present disclosure, but may vary depending on intentions or precedents of those of ordinary skill in the art, emergence of new technologies, and the like. In addition, in a specific case, there is a term arbitrarily selected by the applicant, and in this case, the meaning will be described in detail in the corresponding description. Therefore, the terms used in the present disclosure should be defined based on the meaning of the term and the contents of the present disclosure, rather than the simple name of the term.

In the entire specification, when a part "includes" a certain element, this means that other elements may be further included, rather than excluding other elements, unless otherwise stated.

The expression "at least one of a, b, and c" described throughout the specification means 'a alone', 'b alone', 'c alone', 'a and b', 'a and c', 'b and c ', or 'all of a, b, and c'.

A node described throughout the specification means a redistribution point or an endpoint of communication in a wireless network system, and as a basic element of the network, it can be interpreted as a generic term for computers, terminals, and devices belonging to the local network connected to the network.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings so that those of ordinary skill in the art to which the present disclosure pertains can easily implement them. However, the present disclosure may be implemented in several different forms and is not limited to the embodiments described herein.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings.

1 is a diagram for explaining a wireless network system that can be applied to an embodiment of the present invention.

Referring to FIG. 1 , a wireless network system 100 may include a plurality of nodes 110 and links 120 . The plurality of nodes 110 may be disposed in a specific area, and various links 120 may be activated according to the number of antennas and a half-duplex/full-duplex scheme. Each link 120 is a bidirectional link configured in an uplink or downlink direction, and a signal to interference and noise ratio (SINR) requirement for guaranteeing a specific data rate for each link 120 may be given. Each node 110 may transmit/receive data through a frequency band allocated to the link 120 .

Meanwhile, when frequencies are allocated to the plurality of links 120 based on the optimization algorithm, frequencies may be allocated so that interference between the links 120 is minimized. However, in the case of the optimization algorithm, since frequency allocation is determined according to the number of all cases, computational complexity is high. For example, if the number of usable frequency bands is k and the number of nodes 110 is n, the complexity of an operation for frequency allocation may be about k ⁿ . Therefore, it may be difficult to actually implement the frequency allocation method based on the optimization algorithm. On the other hand, the frequency allocation method and apparatus according to an embodiment of the present disclosure is based on a greedy algorithm, and has a lower computational complexity than an optimization algorithm, and thus a required time may be shortened. Specifically, the computational complexity of the frequency allocation method according to an embodiment may be about n ² .

로 정의될 수 있다. 또한, i번째 링크(120)의 SINR(

)는 수학식 1과 같이 나타낼 수 있다.On the other hand, when a set of nodes included in the wireless network system 100 of FIG. 1 is a set of links and a set of links, the total number of nodes (N) and the total number of links (120) (E) are

can be defined as In addition, the SINR of the i -th link 120 (

) can be expressed as in Equation 1.

[Equation 1]

와

는 j번째 링크 송신 단말과 i번째 링크의 수신 단말 사이의 송신 안테나 이득 및 수신 안테나 이득을 각각 나타낸 것이다. 수학식 1에서, i번째 링크가 아닌 다른 링크로 데이터를 송신하는 단말은 i번째 링크의 수신 단말에게 간섭으로 작용할 수 있다.Here, p _i means the transmission power of the terminal (node) transmitting data through the i -th link,

Wow

? denotes the transmit antenna gain and the receive antenna gain between the j -th link transmitting terminal and the i -th link receiving terminal, respectively. In Equation 1, a terminal transmitting data through a link other than the i -th link may act as interference to a receiving terminal of the i -th link.

는 j번째 링크의 송신 단말과 i번째 링크의 수신 단말 사이 무선 채널 이득을 의미하고, σ ² 은 잡음의 전력을 나타낸다. In addition,

denotes a radio channel gain between the transmitting terminal of the j -th link and the receiving terminal of the i -th link, and σ ² denotes the power of noise.

는 j번째 링크의 송신 단말과 i번째 링크의 수신 단말에 할당된 주파수의 중첩에 따른 간섭 지수를 나타내며, i번째 링크에 할당된 주파수 대역의 중심 주파수가 x _i 이고 j번째 링크에 할당된 주파수 대역의 중심 주파수가 x _j 라고 할 때

로 정의된다. 또한, 무선 네트워크 시스템(100)에서 사용할 수 있는 가용 주파수 대역의 집합을 라고 할 때

이다.On the other hand, in Equation 1

represents the interference index according to the overlap of frequencies allocated to the transmitting terminal of the j -th link and the receiving terminal of the i -th link, the center frequency of the frequency band allocated to the i -th link is x _i and the frequency band allocated to the j -th link When the center frequency of is x _j

is defined as In addition, when a set of available frequency bands usable in the wireless network system 100 is

am.

Meanwhile, each link 120 shown in FIG. 1 must be able to achieve an SINR greater than or equal to a predetermined SINR threshold in order to guarantee a specific data rate. Accordingly, the object of the present invention of allocating frequencies to each link by minimizing the total allocated frequency band while exceeding a predetermined SINR threshold can be expressed as Equation (2).

[Equation 2]

는 무선 네트워크 시스템(100)에 할당된 주파수의 최대값이고,

는 무선 네트워크 시스템(100)에 할당된 주파수의 최소값을 나타낸다. 따라서,

는 링크에 할당된 주파수의 총 대역폭을 의미하며, 요구 대역폭으로도 정의될 수 있다. 또한,

는 i번째 링크의 소정의 SINR 임계값을 나타낸다.where x means the set of frequency bands allocated to the link,

is the maximum value of the frequency allocated to the wireless network system 100,

denotes a minimum value of a frequency allocated to the wireless network system 100 . thus,

Means the total bandwidth of the frequency allocated to the link, and may also be defined as a required bandwidth. In addition,

denotes a predetermined SINR threshold of the i -th link.

Meanwhile, the SINR threshold of each link may be determined based on requirements such as the actual minimum data rate, the average data rate, the maximum delay time, and the communication success probability of each node 110 .

2 is a flowchart illustrating a method of allocating frequencies to a plurality of links according to an embodiment.

In step S210, the frequency allocation device allocates the first frequency band to the first link having the maximum SINR when the first frequency band is allocated, and adds the first link to a first group consisting of links to which frequencies are already assigned. can Here, the first frequency band may be a central frequency band among frequency bands included in the available frequency band.

In step S220, the frequency allocation device calculates the SINR when the first frequency band is allocated for the remaining links except for the links included in the first group in consideration of interference due to the links included in the first group, and calculates A second group may be determined based on the result. Meanwhile, step S220 may be to determine, as the second group, a link having an SINR exceeding a first SINR threshold among links other than the links included in the first group. Also, the first SINR threshold may be a different value depending on the link.

The frequency allocating apparatus according to an embodiment calculates the SINR when the first frequency band is allocated in consideration of the interference caused by the links included in the first group for the remaining links except for the first group, the overlapping frequency interference index can be further considered. In this case, the overlapping frequency interference index may be determined according to the minimum frequency interval. Here, the minimum frequency interval may be defined as a center frequency difference between two adjacent frequency bands. Also, the minimum frequency interval may be determined based on at least one of a center frequency of an available frequency band, information about an execution time, and a required bandwidth.

In step S230, when the first frequency band is allocated to the link included in the second group, the frequency allocating apparatus may calculate the minimum SINR margin value of the link included in the first group.

In step S240, the frequency allocating apparatus may allocate the first frequency band to a link that provides the largest SINR minimum value to the link of the first group among the links included in the second group, based on the calculation result.

Meanwhile, the frequency allocation apparatus according to an embodiment updates the first group by adding a link to which the first frequency band is allocated to the first group, and links to which the first frequency band is allocated among links included in the second group. updating the second group by subtracting It may further include the step of allocating.

In addition, in the frequency allocating apparatus according to an embodiment, if there is no link included in the first group or when the maximum SINR margin minimum value is less than 0 as a result of the calculation, the second frequency separated by a predetermined frequency interval from the first frequency band The method may further include allocating a band to at least one of the links other than the links included in the first group. In this case, the predetermined frequency interval may be determined based on the minimum frequency interval and the number of frequency bands already allocated.

Meanwhile, the frequency allocation method according to an embodiment may increase frequency use efficiency by allocating frequencies in consideration of the overlapping frequency interference index model. Therefore, it is possible to allocate frequencies to a plurality of links with a sufficiently small required bandwidth based on the greedy algorithm without going through a complicated optimization process.

3 is a flowchart illustrating a method of allocating frequencies to a plurality of links according to another embodiment.

A frequency allocation method according to an embodiment of the present disclosure may allocate a frequency based on a greedy algorithm based on received signal strength information, an overlapping frequency interference index, and a predetermined SINR threshold. Here, the received signal strength information may be calculated through Equation 3 based on the transmit power of all links 110 of the wireless network system 100 , transmit/receive antenna gain, radio channel gain information, and the like.

[Equation 3]

,

및

는 수학식 1의

,

및

와 각각 대응된다.Here, a _ij represents the strength of a received signal received by the receiving terminal of the i -th link from the transmitting terminal of the j -th link, and p _j means the transmission power of the terminal transmitting data through the j -th link.

,

and

is in Equation 1

,

and

and each correspond to

In step S310, the frequency allocation method allocates the kth frequency band to the first link having the maximum SINR when the kth frequency band included in the available frequency band is allocated among the plurality of links, and assigns the first link to the first group can be added to Here, k is an index for a frequency band, and may be an integer increasing by 1 from 1. If the first frequency band f ₀ included in the available frequency band is allocated, k = 1, and in this case, the link to which the first frequency band is allocated may be a link determined according to Equation (4).

[Equation 4]

)의 원소 중 중앙값일 수 있다.Here, e means the index of the link having the maximum SINR, and x _e means the frequency band allocated to the e -th link. On the other hand, the first frequency band ( f ₀ ) is a set (

) may be the median of the elements.

)에 추가할 수 있다. 제1 그룹(

)은 이미 주파수가 할당된 링크들이 포함된 그룹으로 정의된다. If the link capable of having the maximum SINR when the first frequency band is allocated is the first link, the frequency allocation method assigns the first link to the first group (

) can be added to first group (

) is defined as a group that includes links that have already been assigned a frequency.

)에 포함된 링크를 제외한 나머지 링크에 대하여, 제1 그룹(

)에 포함된 링크로 인한 간섭을 고려하여 제k 주파수대역이 할당되었을 때의 SINR을 계산할 수 있다. 이때, 주파수 할당 방법은 수학식 1에 기초하여 각 링크에 제k 주파수 대역이 할당되었을 때, 각 링크의 SINR(

)을 계산할 수 있다. In step S320, the frequency allocation method is the first group (

) for the remaining links except for the links included in the first group (

), the SINR when the k -th frequency band is allocated can be calculated in consideration of the interference caused by the link included in the . In this case, the frequency allocation method is based on Equation 1, when the k -th frequency band is allocated to each link, the SINR (

) can be calculated.

)에 포함된 링크를 제외한 나머지 링크 중에서, i번째 링크의 SINR(

)이 제1 SINR 임계값(

)보다 크면, i번째 링크를 제2 그룹(

)으로 결정할 수 있다. 여기서 제1 SINR 임계값(

)은 링크마다 다른 값일 수 있다. 따라서, 서로 다른 QoS(Quality of Service)를 요구하는 노드들에 대하여 서로 다른 SINR 임계값에 따라 주파수를 할당할 수 있는 효과가 있다.In step S330, the frequency allocation method is the first group (

), the SINR of the i -th link (

) is the first SINR threshold (

), the i -th link is assigned to the second group (

) can be determined. where the first SINR threshold (

) may be a different value for each link. Accordingly, there is an effect that frequencies can be allocated according to different SINR thresholds to nodes requiring different quality of service (QoS).

)으로 결정할 수 있다. 다시 말해, 제2 그룹(

)에 포함된 링크들은 제1 링크에 할당된 제1 주파수 대역을 동일하게 할당받을 수 있는 후보 링크들을 의미한다. 이때, 제2 그룹(

)으로 결정될 i번째 링크의 SINR(

)는 수학식 5와 같이 소정의 SINR 임계값(

) 이상의 SINR을 가져야 한다.For example, if k = 1 in step S320, links that do not have significant interference due to the first link even when the first frequency band is allocated in the same way as the first link are grouped into the second group (

) can be determined. In other words, the second group (

) means candidate links that can be equally allocated the first frequency band allocated to the first link. At this time, the second group (

) of the i -th link to be determined as (

) is a predetermined SINR threshold (

) must have an SINR greater than or equal to .

[Equation 5]

는 주파수가 이미 할당된 링크들이 포함된 제1 그룹을 나타내며,

는 제1 그룹(

)에 포함된 링크를 제외한 나머지 링크들의 집합으로, 주파수가 아직 할당되지 않은 링크들이 포함된 그룹이다.here

represents the first group including links to which frequencies have already been assigned,

is the first group (

) is a set of links other than the links included in ), and is a group including links to which frequencies have not yet been assigned.

)에 포함된 j번째 링크에 제k 주파수 대역을 할당하였을 때, 제1 그룹(

)에 포함된 링크들의 SINR 마진 최소값(μ _j )을 계산할 수 있다. In step S340, the frequency allocation method is based on Equation 6, the second group (

) when the k -th frequency band is allocated to the j -th link included in the first group (

), the minimum SINR margin value ( μ _j ) of the links included in the link can be calculated.

[Equation 6]

)에 포함된 i번째 링크의 SINR(

)와 i번째 링크에 대한 소정의 SINR 임계값(

)의 차이(

)를 SINR 마진으로 정의할 수 있고, 제2 그룹(

)에 포함된 각 링크에 제k 주파수 대역이 할당되었을 때, 각 링크에 대한 SINR 마진 최소값(μ)을 구할 수 있다. where the first group (

) of the ith link included in the SINR (

) and a given SINR threshold for the i -th link (

) difference (

) can be defined as the SINR margin, and the second group (

When the kth frequency band is allocated to each link included in ), the minimum SINR margin value ( μ ) for each link can be obtained.

)에 포함된 링크 중 제1 그룹(

)에 포함된 링크에게 가장 큰 SINR 마진 최소값을 제공하는 링크에 제k 주파수를 할당하고 제1 그룹(

) 및 제2 그룹(

)을 업데이트할 수 있다. 예를 들어, k=1인 경우 제2 그룹(

)에 포함된 각 링크에 제1 주파수 대역을 할당하였을 때, 제1 그룹에 포함된 링크의 SINR 마진 최소값(μ)을 계산한 후, 제2 그룹(

)의 링크 중에서 가장 큰 SINR 마진 최소값(μ)을 제공하는 링크에 제1 주파수 대역을 할당하는 것이다. 이렇게 되면 제2 그룹(

)에 포함된 링크 중 제1 그룹(

)에 포함된 링크들에 가장 작은 간섭을 미치는 링크에 주파수를 할당할 수 있다. 이를 수학식으로 표현하면 수학식 7과 같다.In step S350, the frequency allocation method is the second group (

) among the links included in the first group (

), assign the kth frequency to the link that provides the largest SINR margin minimum to the link included in the first group (

) and the second group (

) can be updated. For example, if k = 1, the second group (

), when the first frequency band is allocated to each link included in the second group (

) to allocate the first frequency band to a link that provides the largest SINR margin minimum value ( μ ) among links of . In this case, the second group (

) among the links included in the first group (

), it is possible to allocate a frequency to the link that has the least interference to the links included in the . This can be expressed as Equation (7).

[Equation 7]

)에 포함된 링크 중 SINR 마진 최소값(μ)이 최대가 되는 링크의 인덱스를 나타낸 것이고, x _e 는 e번째 링크에 할당된 주파수 대역을 의미한다. e is the second group (

. _ _{_} _

)에 포함된 링크가 존재하지 않거나, 제2 그룹(

)에 포함된 링크들에 제k 주파수를 할당하였을 때, 제1 그룹(

)에 포함된 링크의 SINR 마진 최소값(μ)이 0보다 작은 경우, 주파수 할당 방법은 단계 S370을 수행할 수 있고, 그렇지 않은 경우 단계 S320을 다시 수행할 수 있다. 제2 그룹(

)에 포함된 링크가 존재하지 않는 것(

)은 제k 주파수를 할당하였을 때 소정의 SINR를 만족할 수 있는 링크가 존재하지 않는다는 것을 의미할 수 있다. 또한, 제2 그룹(

)에 포함된 링크들에 제k 주파수를 할당하였을 때, 제1 그룹(

)에 포함된 링크의 SINR 마진 최소값(μ)이 0보다 작은 것(

)은 제2 그룹(

)에 포함된 링크를 제k 주파수에 할당하였을 때, 이미 주파수가 할당된 다른 링크들에 미치는 간섭이 너무 크다는 것을 의미할 수 있다. 이러한 경우, 제k 주파수에 링크를 추가로 할당하면 소정의 SINR를 보장할 수 없으므로, 다른 주파수에 링크를 할당해야 한다.In step S360, if the second group (

) does not exist, or the second group (

) when the k -th frequency is allocated to the links included in the first group (

), when the minimum SINR margin value ( μ ) of the link included in the link is less than 0, the frequency allocation method may perform step S370, otherwise, step S320 may be performed again. 2nd group (

) does not exist (

) may mean that there is no link that can satisfy a predetermined SINR when the k -th frequency is allocated. In addition, the second group (

) when the k -th frequency is allocated to the links included in the first group (

) where the minimum SINR margin ( μ ) of the link included in ) is less than 0 (

) is the second group (

), when a link included in the k -th frequency is assigned, it may mean that the interference on other links to which the frequency is already assigned is too large. In this case, since a predetermined SINR cannot be guaranteed when a link is additionally allocated to the k -th frequency, a link must be allocated to another frequency.

)에 포함된 링크의 수가 무선 네트워크 시스템(100)에 포함된 링크의 수(E)와 동일하면, 주파수 할당 방법은 복수의 링크에 주파수가 모두 할당된 것으로 판단하고 주파수 할당 방법을 종료할 수 있다. 만약, 그렇지 않은 경우 단계 S380을 수행할 수 있다. 즉, 주파수 할당 방법은

을 만족할 때까지 반복해서 수행될 수 있다.In step S370, if the first group (

), if the number of links included in the wireless network system 100 is the same as the number of links ( E ) included in the wireless network system 100, the frequency allocation method may determine that all frequencies are allocated to the plurality of links and end the frequency allocation method. . If not, step S380 may be performed. That is, the frequency allocation method is

It can be repeated until it is satisfied.

In step S380, the frequency allocation method may increase the frequency band index k by one. Here, the frequency allocation method may determine the center frequency of each frequency band allocated to the link based on Equation (8) in order to lower the interference index between frequencies.

[Equation 8]

는 최소 주파수 간격을 의미하며, 수학식 8에 따라 가용 주파수의 집합은

로 정의될 수 있다. here

is the minimum frequency interval, and according to Equation 8, the set of available frequencies is

can be defined as

4 is a diagram for explaining an overlapping frequency interference index model according to an embodiment.

4 is a graph exemplarily illustrating an overlapping frequency interference index model, comparing an actual measured distribution model, a linear approximated distribution model, and an exponentially approximated distribution model.

=

)에 따른 수학식 1의 중첩 주파수 간섭 지수

를 결정할 수 있다.The difference in the interference effect value between the mathematical approximation model and the actual measurement model may affect the frequency use efficiency and the transmission rate for each link. For example, in the case of the linear approximation distribution model of FIG. 4 , a value higher than the actual interference index value is provided, which means that the interference index is considered high, and thus the predicted performance is lower than the actual transmission rate when allocating frequencies for each link. Therefore, it can be an efficient model for service applications that need to preserve a specific transmission rate for each link. The frequency allocation method according to an embodiment is based on any one of the overlapping frequency interference index modeling results disclosed in FIG. 4 , the minimum frequency interval (

=

) overlapping frequency interference index of Equation 1 according to

can be decided

이므로 간섭 지수가 1이 된다. 즉, 같은 중심 주파수가 할당된 링크는 서로의 수신 신호가 그대로 상대방에게 간섭으로 영향을 미칠 수 있다. 또한, 두 링크에 할당된 주파수가 약 10㎒가 이격 되면(

) 간섭 지수

가 0에 수렴하여 간섭의 영향이 거의 없는 것을 확인할 수 있다. Meanwhile, referring to FIG. 4, when the same center frequency is allocated to different links,

Therefore, the interference index becomes 1. That is, in links to which the same center frequency is allocated, each other's received signals may affect the other by interference. In addition, when the frequencies allocated to the two links are separated by about 10 MHz (

) interference index

converges to 0, and it can be seen that there is little influence of interference.

=

)에 따른 간섭 지수

를 SINR 계산시 반영함으로써, 소정의 SINR을 보장하면서 효율적으로 주파수를 할당할 수 있다. Frequency allocation device according to an embodiment is the minimum frequency interval (

=

) according to the interference index

By reflecting in the SINR calculation, it is possible to efficiently allocate a frequency while guaranteeing a predetermined SINR.

5 to 7 are diagrams for explaining the performance of a frequency allocating apparatus according to an embodiment.

5 is a diagram for comparing the performance of a frequency allocation method based on an optimization algorithm and a frequency allocation method according to an embodiment. The frequency allocation method based on the optimization algorithm of FIG. 5 is a method implemented based on Korean Patent No. 10-1907678, and the result is shown as "Convex Opt." in FIG. Meanwhile, in FIG. 5 , the result of the frequency allocation method according to an embodiment of the present disclosure is shown as “Proposed”.

For the performance experiment, it is assumed that each node 110 uses the same parabolic antenna of 1 GHz or 7 GHz in the wireless network system 100 in which 62 and 80 nodes 110 are disposed, and each link ( 120), the SINR threshold was set to 30 dB. As a result, it can be confirmed that the frequency allocation method according to an embodiment of the present disclosure requires a narrower required bandwidth (Required BW) compared to the prior art, so that the frequency use efficiency is higher.

Specifically, referring to FIG. 5A , when allocating frequencies to the links 120 connected to 62 nodes 110 , the required bandwidth of the frequency allocation method according to an embodiment depends on the type of the parabolic antenna. 40.75 MHz and 25 MHz respectively. This is less than 126 MHz and 54.625 MHz in "Convex Opt." On the other hand, it can be seen that the required bandwidth is reduced when using the 7 GHz para bowling antenna than when using the 1 GHz para bowling antenna. In addition, in the case of maximum SINR (Max SINR), minimum SINR (Min SINR), and average SINR (Avg SINR), it can be seen that “Convex Opt.” based on the optimization algorithm is higher than “Proposed”. However, since the minimum SINR of the frequency allocation method according to an embodiment of the present disclosure exceeds the SINR threshold of 30 dB of each link 120, it can be confirmed that the SINR required for each link is satisfied.

Referring to FIG. 5B , when a frequency is allocated to a link 120 connected to 80 nodes 110 , the required bandwidth of the frequency allocation method according to an embodiment is each according to the type of the parabolic antenna. 65.5 MHz and 30 MHz. This is less than 199.25 MHz and 65.5 MHz in "Convex Opt."

Accordingly, it can be seen that, in the case of the frequency allocation method according to an embodiment, the required bandwidth is reduced as compared with the frequency allocation method based on the optimization algorithm through FIGS. 5A and 5B .

)에 따른 요구 대역폭을 도시한 그래프이다. 구체적으로, 도 6의 (a)는 62개의 노드(110)에 연결되는 링크(120)에 주파수를 할당하는 경우를 나타낸 것이고, 도 6의 (b)는 80개의 노드(110)에 연결되는 링크(120)에 주파수를 할당하는 경우를 나타낸 것이다. 6 shows the minimum frequency spacing (

) is a graph showing the required bandwidth according to Specifically, (a) of FIG. 6 shows a case of allocating frequencies to the links 120 connected to 62 nodes 110 , and FIG. 6( b ) shows links connected to 80 nodes 110 . A case in which a frequency is allocated to (120) is shown.

)과 요구 대역폭 간에 선형적 관계가 있다고 보기는 어렵다. 이는 최소 주파수 간격(

)이 좁으면 하나의 주파수에 중첩하여 할당되는 링크의 수가 감소하기 때문에, 모든 링크에 주파수를 할당하기 위해서 비교적 많은 수의 주파수 대역이 필요하게 되는 반면, 최소 주파수 간격 (

)이 넓은 경우, 하나의 주파수에 중첩하여 할당되는 링크의 수가 비교적 증가하여 비교적 적은 수의 주파수 대역이 필요하기 때문이다.Referring to (a) and (b) of Figure 6, the minimum frequency interval (

) and the required bandwidth, it is difficult to see a linear relationship. This is the minimum frequency interval (

) is narrow, the number of links allocated to overlap one frequency decreases, so a relatively large number of frequency bands are required to allocate frequencies to all links, whereas the minimum frequency interval (

This is because, when ) is wide, a relatively small number of frequency bands is required because the number of links allocated to overlap one frequency is relatively increased.

)을 가질 때, 도 6의 (b)에 나타난 요구 대역폭이 도 6의 (a)에 나타난 요구 대역폭보다 넓은 것을 확인할 수 있다. 한편, 일 실시 예에 따른 방법으로 복수의 링크에 주파수를 할당하는 데 소요되는 시간은 62개 노드의 경우 1분, 80개 노드의 경우 2분 이내일 수 있다.On the other hand, when the number of nodes 110 increases, the number of links 120 may also increase, and accordingly, the required bandwidth may also increase. Therefore, the same minimum frequency interval (

), it can be seen that the required bandwidth shown in (b) of FIG. 6 is wider than the required bandwidth shown in (a) of FIG. 6 . Meanwhile, the time required for allocating frequencies to a plurality of links by the method according to an embodiment may be within 1 minute for 62 nodes and within 2 minutes for 80 nodes.

)에 따른 알고리즘 수행 시간을 도시한 그래프이다. 도 7을 참고하면, 최소 주파수 간격(

)이 1MHz 이내로 좁아지는 경우, 일 실시 예에 따른 주파수 할당 방법의 실행 시간이 급격하게 증가하는 것을 확인할 수 있다. 7 is a minimum frequency interval of a frequency allocation method according to an embodiment (

) is a graph showing the algorithm execution time according to Referring to Figure 7, the minimum frequency interval (

) is narrowed to within 1 MHz, it can be seen that the execution time of the frequency allocation method according to an embodiment is rapidly increased.

8 is a block diagram illustrating an apparatus for allocating a frequency according to an embodiment.

The frequency allocating apparatus 800 may include a memory 810 and a processor 820 , according to an embodiment. In the frequency allocating apparatus 800 shown in FIG. 8, only the components related to this embodiment are shown. Accordingly, it can be understood by those of ordinary skill in the art related to the present embodiment that other general-purpose components may be further included in addition to the components shown in FIG. 8 .

The memory 810 is hardware for storing various types of data processed in the frequency allocating device 800 . For example, the memory 810 may store the data processed by the frequency allocating device 800 and data to be processed. there is. The memory 810 may store at least one instruction for an operation of the processor 820 . Also, the memory 810 may store a program or an application to be driven by the frequency allocating device 800 . The memory 810 is a random access memory (RAM), such as dynamic random access memory (DRAM), static random access memory (SRAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), CD- It may include ROM, Blu-ray or other optical disk storage, a hard disk drive (HDD), a solid state drive (SSD), or flash memory.

The processor 820 may control the overall operation of the frequency allocator 800 and process data and signals. The processor 820 may generally control the frequency allocating apparatus 800 by executing at least one instruction or at least one program stored in the memory 810 . The processor 820 may be implemented as a central processing unit (CPU), a graphics processing unit (GPU), an application processor (AP), or the like, but is not limited thereto.

The processor 820 allocates a first frequency band to a first link having a maximum SINR when a first frequency band is allocated among the plurality of links, and assigns the first link to a first group consisting of links to which frequencies are already assigned. can be added Here, the first frequency band may be a central frequency band among frequency bands included in the available frequency band.

In addition, the processor 820 calculates the SINR when the first frequency band is allocated with respect to the remaining links except for the links included in the first group in consideration of interference due to the links included in the first group, and the calculation result The second group may be determined based on . In this case, the processor 820 may determine, as the second group, a link having an SINR exceeding the first SINR threshold among the links other than the links included in the first group, and the first SINR threshold is determined according to the link. may be different values.

Meanwhile, with respect to the remaining links except for the first group, calculating the SINR when the first frequency band is allocated in consideration of the interference caused by the links included in the first group is calculating the SINR in consideration of the overlapping frequency interference index. and the overlapping frequency interference index may be determined according to the minimum frequency interval.

When the first frequency band is allocated to the link included in the second group, the processor 820 calculates a minimum SINR margin value of the link included in the first group, and based on the calculation result, the link included in the second group Among them, the first frequency band may be allocated to a link that provides the largest SINR margin minimum value to the first group of links.

Meanwhile, the processor 820 updates the first group by adding the link to which the first frequency band is allocated to the first group, and removes the link to which the first frequency band is allocated from among the links included in the second group to obtain the second Groups can be updated. In addition, if there is a link included in the second group and the minimum value of the largest SINR margin is 0 or more as a result of the calculation, the first frequency band may be allocated to at least one of the links included in the second group.

In addition, if the link included in the first group does not exist or the minimum value of the largest SINR margin is less than 0 as a result of the calculation, the processor 820 selects a second frequency band spaced apart by a predetermined frequency from the first frequency band for the first time. It can be assigned to at least one of the links other than the links included in the group.

Here, the predetermined frequency interval may be determined based on the minimum frequency interval and the number of frequency bands already allocated, and the minimum frequency interval is based on at least one of a center frequency of an available frequency band, information about execution time, and a required bandwidth; can be decided.

The processor according to the above-described embodiments includes a processor, a memory for storing and executing program data, a permanent storage such as a disk drive, a communication port for communicating with an external device, a touch panel, a key, a button, etc. user interface devices, and the like. Methods implemented as software modules or algorithms may be stored on a computer-readable recording medium as computer-readable codes or program instructions executable on the processor. Here, the computer-readable recording medium includes a magnetic storage medium (eg, read-only memory (ROM), random-access memory (RAM), floppy disk, hard disk, etc.) and an optically readable medium (eg, CD-ROM). ), and DVD (Digital Versatile Disc)). The computer-readable recording medium may be distributed among network-connected computer systems, so that the computer-readable code may be stored and executed in a distributed manner. The medium may be readable by a computer, stored in a memory, and executed on a processor.

This embodiment may be represented by functional block configurations and various processing steps. These functional blocks may be implemented in any number of hardware and/or software configurations that perform specific functions. For example, an embodiment may be an integrated circuit configuration, such as memory, processing, logic, look-up table, etc., capable of executing various functions by the control of one or more microprocessors or other control devices. can be hired Similar to how components may be implemented as software programming or software components, this embodiment includes various algorithms implemented in a combination of data structures, processes, routines, or other programming constructs, including C, C++, Java ( It can be implemented in a programming or scripting language such as Java), assembler, or the like. Functional aspects may be implemented in an algorithm running on one or more processors. In addition, the present embodiment may employ the prior art for electronic environment setting, signal processing, and/or data processing. Terms such as “mechanism”, “element”, “means” and “configuration” may be used broadly and are not limited to mechanical and physical configurations. The term may include the meaning of a series of routines of software in association with a processor or the like.

The above-described embodiments are merely examples, and other embodiments may be implemented within the scope of the claims to be described later.

Claims (10)

Among the plurality of links, the first frequency band is allocated to a first link having a maximum signal-to-interference-plus-noise ratio (SINR) when the first frequency band is allocated, and the first link is already in frequency. adding to a first group of assigned links;
In consideration of interference due to the link included in the first group, the SINR when the first frequency band is allocated for the remaining links except for the link included in the first group is calculated based on the calculation result determining a second group;
calculating a minimum SINR margin value of a link included in the first group when the first frequency band is allocated to a link included in the second group; and
allocating the first frequency band to a link that provides the largest SINR margin minimum value to the links of the first group among the links included in the second group based on the calculation result; How to allocate frequencies. According to claim 1,
The step of determining the second group based on the calculation result,
determining, as the second group, a link having an SINR exceeding a first SINR threshold among links other than the links included in the first group;
wherein the first SINR threshold is a different value depending on the link. According to claim 1,
updating the first group by adding a link to which the first frequency band is allocated to the first group;
updating the second group by removing a link to which the first frequency band is allocated from among the links included in the second group; and
The method further comprising: allocating the first frequency band to at least one of the links included in the second group when a link included in the second group exists and the minimum value of the largest SINR margin is greater than or equal to 0 as a result of the calculation , a method of allocating frequencies to multiple links. According to claim 1,
If the link included in the first group does not exist or the minimum value of the largest SINR margin as a result of the calculation is less than 0,
The method of allocating frequencies to a plurality of links, further comprising allocating a second frequency band spaced apart from the first frequency band by a predetermined frequency interval to at least one of the links other than the links included in the first group . 5. The method of claim 4,
The predetermined frequency interval is
A method of allocating frequencies to a plurality of links, the method being determined based on a minimum frequency interval and a number of frequency bands already allocated. 6. The method of claim 5,
The minimum frequency interval is
The method according to claim 1, wherein the determination is made based on at least one of a center frequency of an available frequency band, information about a running time, and a required bandwidth. According to claim 1,
Calculating the SINR when the first frequency band is allocated with respect to the remaining links except for the first group in consideration of interference due to the links included in the first group,
SINR is calculated by considering the overlapping frequency interference index,
The method of allocating frequencies to a plurality of links, wherein the overlapping frequency interference index is determined according to a minimum frequency interval. According to claim 1,
The method of allocating frequencies to a plurality of links, wherein the first frequency band is a central frequency band among frequency bands included in an available frequency band. a memory for storing at least one instruction; and
By executing the at least one command,
Among the plurality of links, the first frequency band is allocated to a first link having a maximum signal-to-interference-plus-noise ratio (SINR) when the first frequency band is allocated, and the first link is already in frequency. add to the first group of assigned links;
In consideration of interference due to the link included in the first group, the SINR when the first frequency band is allocated for the remaining links except for the link included in the first group is calculated based on the calculation result determine a second group;
when the first frequency band is allocated to the link included in the second group, calculating a minimum SINR margin value of the link included in the first group;
a plurality of including a processor for allocating the first frequency band to a link that provides the largest SINR margin minimum value to the links of the first group among the links included in the second group based on the calculation result A device that assigns a frequency to a link in As a computer-readable non-transitory recording medium in which a program for executing a method of allocating frequencies to a plurality of links in a computer is recorded,
A method of allocating frequencies to the plurality of links,
Among the plurality of links, the first frequency band is allocated to a first link having a maximum signal-to-interference-plus-noise ratio (SINR) when the first frequency band is allocated, and the first link is already in frequency. adding to a first group of assigned links;
In consideration of interference due to the link included in the first group, the SINR when the first frequency band is allocated for the remaining links except for the link included in the first group is calculated based on the calculation result determining a second group;
calculating a minimum SINR margin value of a link included in the first group when the first frequency band is allocated to a link included in the second group; and
and allocating the first frequency band to a link that provides the largest SINR margin minimum value to the first group link among the links included in the second group based on the calculation result. .

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